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Background and objectives : Anterior cruciate ligament reconstruction (ACLR) often results in quadricep atrophy. The purpose of this study was to compare the bilateral thickness of each quadricep component before and after ACLR. Materials and Methods: Cross-sectional study design. In 14 patients who underwent ACLR, bilateral quadricep muscle thicknesses were measured using a portable ultrasound device, 1 h before and 48-72 h after ACLR. Two-way analysis of variance (ANOVA) was used to compare muscle thickness pre- and post-ACLR between the limbs. Results: The primary finding was that the vastus intermedius (VI) muscle was significantly smaller in the reconstructed limb after ACLR compared to that in the healthy limb (Reconstructed limb; RCL = Pre-operated (PRE): 19.89 ± 6.91 mm, Post-operated(POST): 16.04 ± 6.13 mm, Healthy limb; HL = PRE: 22.88 ± 6.07, POST: 20.90 ± 5.78 mm, F = 9.325, p = 0.009, η 2 p = 0.418). Conclusions: The results represent a selective surgical influence on the quadricep muscle thickness. These findings highlight the need of advanced strengthening exercises in order to restore VI thickness after ACLR.

Background: A femoral bone tunnel in ACL reconstruction can be constructed from the outside in or from the inside out. When doing it inside out, the approach can be via the anteromedial (AM) portal or through the tibial bone tunnel. It has been suggested that better results might be expected by doing it anteromedially. Clinical results after femoral tunnel drilling via the AM or transtibial (TT) techniques in reconstruction of anterior cruciate ligament (ACL) are presented., Methods: Three hundred patients with ACL injuries were chosen for this study from previously collected data on ACL reconstructions. They were divided into two groups: 150 patients treated with AM drilling and 150 treated with TT drilling. In the AM group, the reconstructions were performed using a semitendinosus graft with the Tape Locking Screw (TLS™) technique (n = 87) or Retrobutton™ femoral and BioScrew™ tibial fixation with a semitendinosus-gracilis graft (n = 63). In the TT group, the fixation method used was Rigidfix™ femoral and Intrafix tibial fixation with a semitendinosus-gracilis graft. The evaluation methods were clinical examination, knee scores (Lysholm, Tegner and IKDC) and instrumented laxity measurements (KT-2000™). Our aim was to evaluate if there was better rotational stability and therefore better clinical results when using AM drilling compared to TT drilling., Results: After excluding revision ACL reconstructions, there were 132 patients in the AM group and 133 in the TT group for evaluation. At the 2-year follow-up, there were 60 patients in the AM group (45.5%) and 58 in the TT group (43.6%). There were no statistically significant differences between the groups in any of the evaluation methods used., Conclusion: Both drilling techniques resulted in improved patient performance and satisfaction. We found no data supporting the hypothesis that the AM drilling technique provides better rotational stability to the knee., Trial Registration: ISRCTN registry with study ID ISRCTN16407730. Retrospectively registered Jan 9th 2020.

Purpose: The aim of this study was to assess the functional and clinical results of patients who underwent ACL reconstruction surgery and were divided into subpopulations related to ACL-associated lesions and focused on ALL-associated lesion., Methods: Our retrospective analysis included 62 patients who underwent standard ACL reconstruction surgery in our hospital from 2014 to 2016. The mean follow-up period was 21 months (range 11-35). We divided the sample into two subpopulations due to the presence or absence of ALL tear at the preoperative MRI. In 42 patients out of 62 (68%), ALL lesion was evident. We evaluated in both subpopulations the ACL failure rate, the functional outcomes rated with IKDC, KOOS, Lysholm scores and the clinical assessment of anteroposterior and rotatory instability with the Lachman test and pivot-shift test., Results: The overall re-injury rate in our cohort of patients was 4.8% with a smaller but not a significant difference between the two groups. A statistically significant difference was observed for the three functional scores, favoring the isolated ACL-lesion group (p < 0.05). Similarly, a better Lachman score was observed in the isolated ACL-lesion group, without statistical significance (p = 0.77); overall, the rate of positive test was lower in the isolated ACL-lesion group. We observed a significant difference of residual rotatory instability (positive pivot-shift test) in the two subpopulations (p = 0.036), and 9% of patients in the ACL + ALL lesion group showed residual jerk or subluxation., Conclusion: The additional ALL reconstruction/repair surgery should always be considered in patients with evident ALL tear at the preoperative MRI.

Background: Although knee immobilization may deteriorate the mechanical parameters of the anterior cruciate ligament, such as stiffness and failure strength, it is unknown whether it induces laxity in the whole joint. We examined the effects of immobilization on anterior-posterior joint laxity and mechanical properties of the anterior cruciate ligament, as well as histological and gene expression profiles of the joint capsule in rat knee joints., Methods: Unilateral rat knees were immobilized using an external fixator. Non-immobilized contralateral knees were used as controls. After 3 weeks, anterior-posterior laxity in the whole joint (i.e., a complex of bones, ligaments, and capsule) and stiffness and failure strength in the anterior cruciate ligament were examined using a universal testing machine. Moreover, the knee joint capsule was histologically analyzed, and the expression levels of genes related to collagen turnover in the posterior joint capsule were examined., Findings: Joint immobilization slightly but significantly increased anterior-posterior laxity compared with the contralateral side. Unexpectedly, the stiffness and failure strength of the anterior cruciate ligament were not altered by immobilization. There was no correlation found between anterior cruciate ligament stiffness and anterior-posterior joint laxity. In the posterior joint capsule, thinning of the collagen fiber bundles accompanied by a decrease in COL3A1 gene expression was observed after immobilization., Interpretation: These results suggest that 3 weeks of joint immobilization alters the biomechanical integrity in the knee joint without altering the mechanical properties of the anterior cruciate ligament. Changes in the joint capsule may contribute to the immobilization-induced increase in anterior-posterior laxity., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The current study looks to: (i) investigate postural stability following anterior cruciate ligament (ACL) reconstruction, as assessed by Y-Balance Test, by comparing single-leg balance of the injured limb against those of controls and the uninjured limb; (ii) analyze the relationship between postural stability symmetry with localized cartilage matrix changes and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Bilateral knee MRI of 36 patients who underwent ACL reconstruction were performed before surgery, 6 months, 1 year, and 2 years, postoperatively. Postural stability was evaluated based on Y-Balance Test at 1 and 2 years. ACL patients were also split into three groups based on postural stability symmetry at 2 years and symmetry thresholds associated with elevated risks of lower extremity injury. Voxel-based relaxometry employing analysis of covariance was used to analyze localized differences in cartilage composition at all time-points (using quantitative magnetic resonance [MR] T1ρ and T2 mapping) between the three groups. The ACL patients displayed no significant deficits in postural stability. Compared with symmetric patients, those with asymmetric postural stability at 2 years had significantly prolonged cartilage T1ρ-indicating deterioration of the cartilage matrix-specifically in the injured knee's medial tibia as early as 6-month post-reconstruction. Prolonged T1ρ in asymmetric patients persisted up to 2 years, where the group also reported worse KOOS. Our results demonstrate an association between early stages of cartilage matrix deterioration and postural stability symmetry that may manifest in elevated lower extremity injury risk and worse patient-reported outcomes. Quantitative MR, in combination with local analysis performed with voxel-based relaxometry, is a tool to further study this relationship. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:1132-1140, 2020., (© 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Introduction: Rehabilitation after anterior cruciate ligament (ACL) reconstruction is critical to patient outcome. Despite its importance; however, hospital-based rehabilitation is limited, with barriers, including distance and cost. With recent technological advancements, wearable devices have actively been used to address these barriers. In this study, we propose a randomized controlled trial protocol investigating the efficacy and feasibility of home-based rehabilitation after ACL reconstruction using a smart wearable device providing electrical stimulation that allows knee exercise., Methods and Analysis: This is a protocol proposal for a prospective, single-center, randomized, controlled study. We plan to recruit adults discharged after ACL reconstruction; the recruited subjects will be randomly allocated to 1 of 2 groups, using a computer-generated randomization method: the intervention (n = 20) or control group (n = 20). The intervention group will receive a 6-week home-based rehabilitation program using smart wearable device. The control group will undergo a 6-week self-exercise program as normal. The following outcomes will be assessed at baseline, 2 weeks, and 6 weeks post the 6-week intervention program: quadriceps strength of the affect side as measured by a dynamometer (primary outcome); range of motion; root mean square of quadriceps muscle using surface electromyography; knee function using questionnaire; quality of life; subject's satisfaction score using questionnaire; frequency and duration of exercise; and knee pain. An intention-to-treat analysis will be conducted for the primary outcome., Discussion: This study is a prospective, single-center, randomized, controlled study. This study aims to research the feasibility and efficacy of a 6-week, structured home-based rehabilitation program for patients after ACL reconstruction using a smart wearable device. The findings of this study will help to establish a home-based rehabilitation program to better recovery in patients with ACL reconstruction., Trial Registration Number: This protocol was registered in ClinicalTrials.gov, under the number NCT04079205.

Objectives: The aim of this study was to describe the characteristics and long-term outcome of surgically and conservatively treated cats with cranial cruciate ligament disease (CCLD)., Methods: A retrospective cohort study of cats with CCLD, diagnosed at two university animal hospitals between January 2011 and December 2016, was performed. Signalment, history, treatment and follow-up information were retrieved. Cat owners were contacted for additional long-term follow-up information. The cases were divided into two groups: one conservatively managed and one surgically treated with the lateral fabellotibial suture technique. A quality of life questionnaire, the Feline Musculoskeletal Pain Index (FMPI), was distributed to the owners of cats alive at follow-up for assessment of chronic pain as a long-term outcome. Univariable statistical methods were used to evaluate the data., Results: Fifty cats were identified and were followed for a median of 41 months after diagnosis of CCLD. Seven cats (14%) developed bilateral CCLD. Twenty-eight cats (56%) were treated conservatively and 22 (44%) surgically. All surgically treated cats in which arthrotomy was performed (19/22) had total cranial cruciate ligament rupture and 9/19 (47%) had meniscal injuries. Postoperative surgical complications were recorded in 6/22 cats (27%). Owners of 24/29 (83%) cats still alive at follow-up completed the FMPI questionnaire. The conservatively treated cats had a lower FMPI score, indicating less chronic pain, than those cats treated surgically ( P = 0.017)., Conclusions and Relevance: Conservatively treated cats with CCLD experienced less chronic pain at long-term follow-up than surgically treated cats. Bilateral disease is not uncommon in cats with CCLD.

Introduction: Symptomatic osteoarthritis (OA) in the knee is defined as the presence of OA radiographic features in combination with knee symptoms. Pain has not been shown to correlate meaningfully to radiographic severity. We aimed to determine the relationship between a tear of the anterior cruciate ligament (ACL) with knee symptoms and radiographic OA., Methods: A within-person, between-knee cross-sectional study of 37 participants from the Osteoarthritis Initiative (OAI) with a complete or partial ACL tear detected on magnetic resonance imaging in 1 knee (index knee) were included. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS) and radiographs of both knees, 1 with an ACL tear and one without (control knee) were scored for OA severity (Kellgren-Lawrence Grading) and symptoms. A generalized estimating equation with linear regression was used to compare symptom scores within individuals as well as to radiographic severity., Results: Thirty-seven individuals (40% female, average age = 60.7years, body mass index = 31.0 kg/m 2 ) reported no difference in knee symptoms (WOMAC pain odds ratio [OR] =1.92, 95%CI 0.699-5.248, P = .21; KOOS symptoms OR = 2.12, 95%CI 0.740-6.065, P = .09), stiffness (OR = 1.67, 95%CI 0.653-5.583, P = .35) or functional disability (OR = 1 0.97, 95%CI 0.515-7.508, P = .32) in the knee that exhibited an ACL tear compared to the control knee. Only knee function and disability (WOMAC Disability OR = 1.12, 95%CI 1.003-1.249, P = .04) were associated with radiographic severity between index and control knees., Conclusion: Individuals did not report an increase in knee pain, stiffness or disability in their ACL-deficient knee. Only disability was associated with worsening severity of radiographic OA in ACL-deficient knees., (© 2020 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

Background: Partial lesions of the anterior cruciate ligament (ACL) are more common than is generally thought, accounting for about 10-12% of ACL injuries. Selective reconstruction may be considered as an option in isolated bundle rupture. The purpose of this study is to evaluate both subjective and objective clinical results, as well as functional recovery time, after selective arthroscopic single-bundle reconstruction in a consecutive series of patients affected by partial ACL rupture., Materials and Methods: Thirty-six patients undergoing selective reconstruction of a single ACL bundle were retrospectively evaluated from a series of 354 ACL reconstructions performed over a 3-year period. Although the suspicion of partial lesions was present at clinical and magnetic resonance imaging (MRI) evaluation, final diagnosis was obtained during arthroscopy. All patients were operated using the same technique and type of fixation, and undergoing the same functional recovery protocol., Results: Mean follow-up was 64 months (48-84 months). All patients but one achieved good functional recovery and returned to their sports within a mean period of 6.1 months. A single patient complained of postoperative instability 1 year after the index operation and needed further surgery. No complications were recorded., Conclusions: Selective reconstruction of partial ACL injury is a method to bear in mind because it offers quick functional recovery. Specific technical and diagnostic steps should be performed and discussed with patients preoperatively., Level of Evidence: Level 4, retrospective study.

Background: Anterior tibial subluxation (ATS) in extension after anterior cruciate ligament (ACL) injury highlights an increased anterior position of the tibia relative to the femur. Recent studies demonstrated that subluxation is sometimes irreducible and the normal tibiofemoral relationship is not restored by ACL reconstruction (ACLR), which raises concerns regarding clinical outcomes after ACLR., Hypothesis: Excessive preoperative ATS in extension is associated with inferior knee stability after anatomic ACLR., Study Design: Cohort study; Level of evidence, 3., Methods: From March 2016 to January 2017, a total of 487 consecutive patients with clinically diagnosed noncontact ACL injuries who underwent primary anatomic ACLR were retrospectively analyzed. Of these patients, 430 met the criteria for inclusion in this study. Anterior subluxation of the lateral and medial compartments (ASLC and ASMC) in extension relative to the femoral condyles was measured on preoperative magnetic resonance imaging. Twenty patients (study group) who demonstrated excessive (>10 mm) ASLC and ASMC in extension were matched 1:2 to 40 participants (control group) who showed minimal or no (<3 mm) ASLC and ASMC in extension. The amount of ASLC and ASMC in extension relative to the femoral condyles at 2 years postoperatively was the primary outcome. Moreover, the Lysholm score, IKDC grade (International Knee Documentation Committee), and stability assessments (pivot-shift test and KT-1000 arthrometer side-to-side difference) were evaluated preoperatively and at the last follow-up visit., Results: The preoperative mean ASLC and ASMC in extension of the study group were both significantly larger than those of the control group (study group vs control group: ASLC, 13.5 mm vs 1.2 mm; ASMC, 12.4 mm vs 1.0 mm; P < .05). Moreover, patients in the study group showed significantly larger posterior tibial slope than the patients in the control group (17.8°± 2.5° vs 9.5°± 1.5°; P < .05). At the final follow-up visit, the mean ASLC and ASMC of the study group were 8.1 mm and 7.3 mm, which were significantly larger than those of the control group (ASLC, 0.9 mm; ASMC, 0.7 mm; P < .05). In addition, the study group showed inferior knee stability when compared with the control group in terms of both the pivot-shift test (study group vs control group: 2 grade 2, 10 grade 1, and 8 grade 0 vs 1 grade 1 and 39 grade 0; P < .05) and the KT-1000 arthrometer side-to-side difference (study group vs control group: 4.4 ± 1.2 mm vs 1.5 ± 0.6 mm; P < .05). Furthermore, the study group showed significantly lower mean Lysholm score (study group vs control group: 80.3 ± 6.3 vs 93.3 ± 4.3, P < .05) and IKDC grading results (study group vs control group: 3 grade C, 16 grade B, and 1 grade A vs 3 grade B and 37 grade A; P < .05) as compared with the control group., Conclusion: In this short-term study, the excessive (>10 mm) preoperative ATS in extension after ACL injury was associated with inferior knee stability after anatomic ACLR.

Background: Lubricin, a mucinous glycoprotein, plays a chondroprotective role as a constituent of synovial fluid. Structural analogs have been synthesized to mimic the structure and function of native lubricin in an effort to recapitulate this effect with the goal of delaying progression of osteoarthritis (OA)., Purpose: To investigate the efficacy of intra-articular injections of lubricin mimetics in slowing or preventing the progression of posttraumatic OA by using a rat anterior cruciate ligament transection model., Study Design: Controlled laboratory design., Methods: Four lubricin mimetics were investigated, differing from one another in their binding orientations and steric interactions. Eighty skeletally mature Sprague-Dawley rats underwent bilateral anterior cruciate ligament transections and were randomly allocated to receive intra-articular injections (50 µL/injection) of 1 of the 4 mimetics in the right knee and equal volumes of saline injection in the contralateral knee (control). All rats were euthanized 8 weeks postoperatively and assessed via biomechanical analysis, which evaluated comparative friction coefficients across the 4 groups, and histological evaluation of articular cartilage, osteophytes, and synovitis. The Osteoarthritis Research Society International (OARSI) histopathological assessment system was used to evaluate the degree of articular cartilage degeneration and osteophytes, while synovitis was assessed through a semiquantitative scoring system. Binding efficacy of the 4 mimetics was assessed in vitro and in vivo through the immunohistochemical localization of polyethylene glycol. Articular cartilage degeneration and synovitis scoring data analyses were performed with generalized estimating equation modeling., Results: Injection of the group 3 mimetic (random 24 + 400 + 30) directly correlated with improved OARSI scores for femoral articular cartilage degeneration when compared with saline-injected contralateral control knees ( P = .0410). No lubricin mimetic group demonstrated statistically significant differences in OARSI scores for tibial articular cartilage degeneration. Injection of the group 4 mimetic (AB 24 + 400 + 30) led to a statistically significant difference in osteophyte OARSI score ( P = .0019). None of the 4 lubricin mimetics injections incited an additive synovial inflammatory response. Immunohistochemical staining substantiated the binding capacity of all 4 mimetics, while in vivo experimentation revealed that the group 1 and 3 mimetics were still retained within the joint 4 weeks after injection. There were no differences in friction coefficients between any pair of groups and no significant trends based on lubricin mimetic structure., Conclusion: We demonstrated that the tribosupplementation of a traumatically injured knee with a specific lubricin structural analog may attenuate the natural progression of OA., Clinical Relevance: The current lack of efficacious clinical options to counter the onset and subsequent development of OA suggests that further investigation into the synthesis and behavior of lubricin analogs could yield novel translational applications.

The choice of grafts for anterior cruciate ligament (ACL) reconstruction is a critical issue in sports medicine. Previous studies have revealed that scaffolds prepared from a single material could not achieve complete integration between the graft and autogenous bone tunnel. To solve this problem, we hypothesize that combining degradable scaffolds with nondegradable scaffolds can produce a novel hybrid ligament with the advantages of both types of scaffolds. In this study, a bone morphogenetic protein 7 (BMP-7)-loaded polycaprolactone (PCL) nanofibrous membrane was first manufactured as the degradable part of the hybrid ligament by using layer-by-layer (LbL) self-assembly. Then, we fabricated a multifunctional novel hybrid ligament by rolling up this nanofibrous membrane and polyethylene terephthalate (PET) mesh fabric (nondegradable part) into a "swiss roll" structure. The in vitro experimental results showed that this hybrid ligament could significantly improve the biocompatibility of pure PET ligament and further promote cell mineralization. The in vivo experimental results showed that this unique structure significantly promoted the integration of hybrid ligaments and bone tunnels, thereby achieving real "ligamentization" after ACL reconstruction surgery. These results suggest that this novel hybrid biomimetic artificial ligament scaffold provides a new direction for graft selection for ACL reconstruction.

Objective: To evaluate the feasibility of point-of-care knee ultrasonography (POCUS) compared with knee magnetic resonance imaging (MRI) for diagnosing anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) tears in patients with acute knee trauma., Material and Methods: A prospective study was conducted in a tertiary hospital emergency department; acute (within 1-week) knee trauma patients with suspected ACL or PCL tear were recruited. Two POCUS performers (a board-certified emergency physician and a musculoskeletal radiologist) independently evaluated the ACL and PCL using POCUS. Findings were classified as normal appearance or ligament tear. Final radiology reports of knee MRI were used as the reference standard. We calculated the diagnostic values (sensitivity, specificity, and accuracy) for POCUS obtained by both POCUS performers. Kappa values (k) were calculated for inter-observer agreement between the two POCUS performers., Results: Sixty-two patients were enrolled. Compared with the reference standard, POCUS showed acceptable sensitivity (90.6-100%), specificity (90.0-97.7%), and accuracy (91.9-96.8%). Inter-observer agreement between the two POCUS performers was excellent (k = 0.853-0.903)., Conclusion: POCUS demonstrates excellent precision as compared to MRI in the diagnosis of ACL and PCL tears. The findings of POCUS could be used for immediate diagnosis and further pre-operative imaging in patients with acute knee trauma., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: To compare the effect of independent suture tape reinforcement on the dynamic elongation and stiffness behavior as well as ultimate strength of tripled smaller-diameter and quadrupled soft-tissue grafts for anterior cruciate ligament reconstruction (ACLR) with tibial screw fixation in a biomechanical in vitro study., Methods: Tripled smaller-diameter (8 mm) and quadrupled (9 mm) bovine tendon grafts with and without suture tape reinforcement (n = 8 in each group) were tested using femoral suspensory and tibial interference screw fixation. The suture tape was femoral sided and fixed independent from the graft by passing it through the suspensory button and securing the 2 open tibial strands with a secondary interference screw. Dynamic testing was performed in position and force control at 250 N and 400 N, followed by pull to failure with the mode of failure noted. Dynamic elongation, stiffness, and ultimate strength were analyzed., Results: Tripled constructs showed a significantly worse structural performance than quadrupled constructs at higher loads. Reinforcement of tripled and quadrupled grafts substantially decreased total elongation by 56% (4.54 ± 0.75 mm vs 2.01 ± 0.50 mm, P < .001) and 39% (3.25 ± 0.49 mm vs 1.98 ± 0.51 mm, P < .001), respectively, by significantly increasing dynamic stiffness. No statistical significance was found between the reinforced groups. Failure loads of reinforced tripled (1,074 ± 148 N vs 829 ± 100 N, P = .003) and quadrupled (1,125 ± 157 N vs 939 ± 76 N, P = .023) grafts were also significantly improved., Conclusions: Independent reinforcement of soft-tissue grafts with suture tape strengthened the performance especially of tripled smaller-diameter grafts for ACLR with tibial screw fixation by significantly improving dynamic elongation at increased stiffness and ultimate strength. Quadrupled reinforced grafts showed no over-constraining and structurally behaved similarly to tripled grafts with reinforcement., Clinical Relevance: Independent reinforcement for ACLR may provide an option for protecting autografts or allografts against irreversible lengthening during the maturation and remodeling phases of healing., (Copyright © 2019 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Anterior cruciate ligament injuries are commonly combined with meniscal tears. This study was performed to analyze the kinematics and kinetics of knees with anterior cruciate ligament deficiency with or without a combined medial or/and lateral meniscal injury during level walking. In all, 29 patients with unilateral anterior cruciate ligament deficiency and 15 healthy male volunteers were recruited. Among these patients, 12 had isolated unilateral anterior cruciate ligament injuries (ACLD group), 5 had combined anterior cruciate ligament and lateral meniscal injuries (ACLDL group), 5 had combined anterior cruciate ligament and medial meniscal injuries (ACLDM group), and 7 had combined anterior cruciate ligament and medial/lateral meniscal injuries (ACLDML group). A subject-specific musculoskeletal multibody dynamics model was utilized to estimate the tibiofemoral joint kinematic and kinetic behaviors based on the experimental data measured by using an optical tracking system. Regardless of the presence or absence of meniscal injury, the knees with anterior cruciate ligament deficiency exhibited significantly less extension than the control knees at the terminal stance (range of extension: ACLD, 4.84° ± 4.31°; ACLDL, 6.65° ± 5.73°; ACLDM, 5.21° ± 4.77°; ACLDML, 6.91° ± 4.30°; control, 12.35° ± 5.52°; P  < 0.05). A lower extension moment and adduction moment in all anterior cruciate ligament deficiency affected knees were detected during the terminal stance when compared with control knees ( P  < 0.05). The ACLDML group showed significantly lower proximal-distal compressive forces and anterior-posterior shear forces (approximately 0.5-1.5 body weight; P  < 0.05) compared to the other 4 groups, while the anterior-posterior and medial-lateral shear forces tended to increase in the ACLD, ACLDL, and ACLDM groups at the mid to terminal stance. Significant lower adduction-abduction and internal-external moment peaks were observed in ACLDML groups, but not in the ACLD, ACLDL and ACLDM groups. These results indicate that the combination of an anterior cruciate ligament injury and meniscal injury could alter the kinematics and kinetics of anterior cruciate ligament deficiency affected knees depending on the presence and type of the meniscal tear.

Background: Proprioceptive recovery has received an increased amount of attention after undergoing anterior cruciate ligament (ACL) reconstruction. However, ACL reconstruction without rehabilitation training could not significantly improve the reduction and function of the proprioceptor. This study aimed to explore whether nerve growth factor (NGF) could cause proprioceptive changes after ACL reconstruction through histopathological and electrophysiological evaluations., Methods: A total 28 mature New Zealand white rabbits were used in the study, 24 to develop the model of ACL injury and ACL reconstruction. These included the experimental group (n=12; injected with NGF 20 µg/week at the second month after surgery) and the experimental control group (n=12), and 4 for blank control group. In the 4th, 8th, and 12th months, the changes in ACL nerves were measured by somatosensory evoked potentials (SEPs) and electromyogram (EMG). Furthermore, gold chloride staining was performed to detect the changes in morphology and quantity of the proprioceptors in ACL., Results: Electrophysiological tests showed that the incubation of SEPs and EMG in both the experimental group and the experimental control group were prolonged, and the amplitude decreased when compared with the blank control group (all, P<0.05). Also, in comparison to the experimental control group, the experimental group injected with NGF had a shorter incubation and higher amplitude (all, P<0.05). Furthermore, histopathology analysis revealed that the number of proprioceptors in the experimental group injected with NGF was significantly increased, and the atypical structure was reduced (all, P<0.05)., Conclusions: The results showed the injection of NGF (injected with 20 µg/week in the second month after surgery) could improve joint function rehabilitation by promoting function and quantity of proprioception after ACL reconstruction.

Background and Objective: In the available literature there are no reports on the effectiveness of Kinesio Taping (KT) in the conservative treatment of patients with anterior instability of the knee. The purpose of the present research was to evaluate the influence of the selected KT technique in limiting the anterior translation of the tibia by performing a biomechanical analysis of the gait cycle of patients with anterior instability of the knee., Methods: A total of 31 patients qualified for the single group study. In all patients, a total tear of the anterior cruciate ligament was diagnosed. The research tool was a three-dimensional motion analysis BTS SMART system. The effectiveness of KT of the knee with an anterior cruciate ligament tear was assessed based on angular changes in the movement of the knee in three planes of motion during specific phases of the gait cycle., Results: The results show that KT does not significantly affect angular values of the knee joint in the sagittal and transverse planes of the affected and healthy limb during selected phases of the gait cycle., Conclusions: Due to only observed changes in the frontal plane, the KT method should be modified to also improve knee function in other planes.

Purpose: This is a systematic review and meta-analysis of current evidence that aims at comparing the clinical outcomes of remnant-preserving anterior cruciate ligament reconstruction (ACLR) and standard ACLR., Methods: A systematic review of randomized controlled studies and cohort studies comparing remnant-preserving ACLR with standard ACLR with a minimum level of evidence of II was performed. Studies were included by strict inclusion and exclusion criteria. Extracted data were summarized as preoperative conditions, postoperative clinical outcomes, and postoperative complications. When feasible, meta-analysis was performed with RevMan5.3 software. Study methodological quality was evaluated with the modified Coleman methodology score (CMS)., Results: Eleven studies ( n  = 466 remnant-preserving and n  = 536 standard) met the inclusion criteria. The mean modified CMS for all included studies was 85.8 (range: 77-92 on a 100-point scale). In total, 466 patients underwent remnant-preserving ACLR by 3 different procedures: standard ACLR plus tibial remnant tensioning ( n  = 283), selective-bundle augmentation ( n  = 49), and standard ACLR plus tibial remnant sparing ( n  = 134). Remnant-preserving ACLR provided a superior outcome of postoperative knee anterior stability (WMD = -0.42, 95% CI, -0.66, -0.17; P < 0.01) and Lysholm score (WMD = 2.01, 95% CI, 0.53 to 3.50; P < 0.01). There was no significant difference between the two groups with respect to second-look arthroscopy (OR = 1.38, 95% CI, 0.53, 3.62; P =0.51), complications (OR = 1.24 95% CI, 0.76, 2.02; P =0.39), International Knee Documentation Committee (IKDC) subject scores, IKDC grades, Lachman test, and pivot-shift test., Summary/conclusion: Remnant-preserving ACLR promotes similar graft synovial coverage and revascularization to standard ACLR. Equivalent or superior postoperative knee stability and clinical scores were observed for remnant-preserving ACLR compared with standard ACLR. No significant difference in the total complication rate between the groups was evident., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2019 Han Wang et al.)

Background: Within the emergency department (ED) setting, anterior cruciate ligament (ACL) rupture is commonly misdiagnosed, leading to improper treatment and potential meniscal injury and total joint replacement. Utilizing traditional clinical tests to diagnosis ACL rupture leads to the correct diagnosis in about 30% of cases. The lever sign is a new and effective clinical test used to diagnose ACL rupture with 100% sensitivity., Objective: We aim to study if the lever sign used in the ED setting is more sensitive to diagnose ACL rupture than traditional tests., Methods: Patients between 12 and 55 years of age were examined utilizing either traditional methods or the lever sign. Diagnostic findings in the ED were compared with those of a sports medicine specialist using magnetic resonance imaging as the diagnostic standard. A survey was given to ED providers to collect data on diagnosis and physician confidence in diagnosis., Results: The sensitivity of the lever sign was 100% (94.7% accuracy, 93.75% specificity), whereas the sensitivity of the anterior drawer/Lachman test was 40% (87.5% accuracy, 100% specificity). Physician confidence in diagnosis was higher utilizing the lever sign vs. the anterior drawer/Lachman test at 8.45 (±1.82) compared with 7.72 (±1.82) out of 10, respectively. There was no statistically significant association between diagnostic accuracy with either test and level of training of the ED provider., Conclusion: Implementation of the lever sign in the ED setting resulted in a higher sensitivity, higher physician confidence in screening test diagnosis, and a decrease in the number of undiagnosed ACL ruptures., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Handball is one of the most popular team sports in Germany, as well as one of the most dangerous ones. Injury rates in Germany are higher amongst handball professionals than in soccer, with the knee being the most commonly injured joint. To prevent injuries, a functional inert stability is necessary, but definitions and objective measures are lacking., Objectives: Establishing valid reference data of functional knee stability in amateur handball players with use of an established test battery giving objective measures METHODS: 261 athletes (f:130; m:131), mean age 25.1 ± 5.8 y were screened during the preseason. The test battery consisted of double and single-leg counter movement jumps, balance tests, agility, parkour, quick feet test and plyometric jumps., Results: Significant differences between males and females were noted in regard to balance scores (favour for females p ≤ 0.001), as well as jump height, agility and speed tests (favour for males [p ≤ 0.002-0.001])., Conclusion: The noted differences once again bring focus to the interindividual presence of risk factors, because female and male handball athletes have gender-specific ground levels. These attributes have to be considered in further screening and prevention programs, as well as in the context of the return-to-sports decision after injury. The given data may serve as objective reference measures.

Background: There is currently no consensus among orthopaedic surgeons as to when patients with anterior cruciate ligament reconstruction are ready to return to sport or whether or not patients should wear a functional knee brace during athletic activity. The purpose of the present study was to determine the effects of time since return to sport and of a functional knee brace on hop distance and loading symmetry during hop testing in patients with anterior cruciate ligament reconstruction., Methods: Twenty-eight patients with anterior cruciate ligament reconstruction completed hop testing after being released to return to sport and again 3 months later, both with and without wearing a custom fit extension constraint functional knee brace. The loadsol® captured plantar loading data (100 Hz) to quantify peak impact force, loading rate, and impulse during the final landing of every hop test. A limb symmetry index was calculated between surgical and non-surgical limbs for hop distance and loading measures., Findings: Wearing a knee brace increased hop distance symmetry during the single and crossover hop tests and peak impact force symmetry on each test (all p < 0.05). While single (p = 0.022) and triple (p = 0.002) hop distance symmetry increased with time, there was no effect of time on any loading symmetry outcomes., Interpretation: These results support using a functional knee brace during athletic activities for improving symmetry in the early return to sport period. These results also support previous findings that while hop distance symmetry improves with time, asymmetrical landing mechanics do not and should be addressed clinically., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: The current gold standard for the treatment of an anterior cruciate ligament (ACL) rupture is reconstruction with tendon graft. Recently, two surgical ACL repair techniques have been developed for treating an acute ACL rupture: Dynamic Intraligamentary Stabilization (DIS, Ligamys®) and Internal Brace Ligament Augmentation (IBLA, InternalBrace™). We will conduct a single-blind, multi-center, randomized controlled trial which compares DIS, IBLA and reconstruction for relative clinical efficacy and economic benefit., Methods: Subjects, aged 18-50 years, with a proximal, primary and repairable ACL rupture will be included. DIS is preferably performed within 4 weeks post-rupture, IBLA within 12 weeks and reconstruction after 4 weeks post-rupture. Patients are included in study 1 if they present within 0-4 weeks post-rupture and surgery is feasible within 4 weeks post-rupture. Patients of study 1 will be randomized to either DIS or IBLA. Patients are included in study 2 if they present after 4 weeks post-rupture and surgery is feasible between 5 and 12 weeks post-rupture. Patients of study 2 will be randomized to either IBLA or reconstruction. A total of 96 patients will be included, with 48 patients per study and 24 patients per study arm. Patients will be followed-up for 2 years. The primary outcome is change from baseline (pre-rupture) in International Knee Documentation Committee score to 6 months post-operatively. The main secondary outcomes are the EQ-5D-5 L, Tegner score, Lysholm score, Lachman test, isokinetic and proprioceptive measurements, magnetic resonance imaging outcome, return to work and sports, and re-rupture/failure rates. The statistical analysis will be based on the intention-to-treat principle. The economic impact of the surgery techniques will be evaluated by the cost-utility analysis. The LIBRƎ study is to be conducted between 2018 and 2022., Discussion: This LIBRƎ study protocol is the first study to compare DIS, IBLA and ACL reconstruction for relative clinical efficacy and economic benefit. The outcomes of this study will provide data which could aid orthopaedic surgeons to choose between the different treatment options for the surgical treatment of an acute ACL rupture., Trial Registration: This study is registered at ClinicalTrials.gov; NCT03441295. Date registered 13.02.2018.

Objective: The purpose of this study was to determine the effects of lower extremity motor control exercises on knee proprioception, muscle strength, and functional level in patients with anterior cruciate ligament reconstruction (ACL-R)., Materials and Methods: Thirty-two of the 57 patients with ACL-R using tibialis anterior allografts were divided into two groups. Group I: lower extremity motor control exercises were added to the standard rehabilitation program. Group II: standard rehabilitation program was applied. Effects of lower extremity motor control exercises on quadriceps and hamstring muscles strength, knee joint position sense, and hop test were evaluated., Results: There were no differences in muscle strength and endurance of the quadriceps and hamstring between the operative and nonoperative sides in Group I ( p > 0.05) while there were significant differences in strength of the quadriceps and hamstring between the operative and nonoperative sides in Group II ( p < 0.05). There were significant differences in the endurance of the quadriceps and hamstring and knee joint position sense at 15°, 45°, and 75° between the operative sides of the patients in both groups ( p < 0.05)., Conclusions: The neuromuscular control exercises program was found to be more effective in reducing the difference in strength while the standard program was found to be more effective in reducing the difference in endurance between the operated knee and the other knee. This study revealed that neuromuscular control exercises should also be used to improve knee proprioception sense following ACL-R., Competing Interests: All authors have no conflicts of interest with respect to the data collected and procedures used within this study., (Copyright © 2019 Defne Kaya et al.)

Purpose: To evaluate the effects of different stitching methods and suture diameters on the graft fixation of soft tissue human quadriceps tendon grafts for anterior cruciate ligament (ACL) reconstruction., Methods: The Krackow locking stitch (K), whipstitch (W), and baseball stitch (B) were combined with either a 2× no. 2 (#2) or a 1× no. 5 (#5) braided composite suture for graft fixation of 36 human quadriceps tendons in 6 groups. Biomechanical testing was performed using a cyclic protocol with loads between 0 and 100 N. The maximum load until failure, cyclic elongation, and failure mode were recorded., Results: The highest mean maximum load to failure was observed in the 2 Krackow stitch groups. The K#2 group had significantly higher load to failure values compared with those of the W#2 and B#2 groups (K#2, 553 ± 82 N vs W#2, 392 ± 107 N, P = .0349; K#2 vs B#2 366 ± 118 N, P = .0129). The mean cyclic elongation was lowest in the Krackow groups (K#2, 10.59 ± 2.63 mm; K#5, 13.66 ± 2.3 mm). The regular failure mode was the rupture of the suture for the Krackow stitch (8 of 12) and suture pullout for the whipstitch (11 of 12) and baseball stitch groups (12 of 12)., Conclusions: The double Krackow stitch with no. 2 braided composite suture exhibits a high maximum load to failure combined with a low amount of elongation in a biomechanical study for human quadriceps tendon soft tissue graft fixation. Unlike the whipstitch and the baseball stitch, it can solidly prevent suture pullout., Clinical Relevance: A safe soft tissue graft fixation technique is especially important for quadriceps tendon grafts with their laminar anatomical structure and physiologically varying diameter. Unlike other grafts for ACL replacement, it fully relies on the soft tissue suture fixation to resist the pullout force., (Copyright © 2019 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Purpose: Few studies describe the specific results of anterior cruciate ligament reconstruction with pedicled hamstring graft (HG). Our goal was to report the isokinetic, clinical, and functional outcomes over the post-operative year following pedicled hamstring ligamentoplasty., Methods: Twenty-four patients with ACL rupture (mean age 27.4 years) were included prospectively. The technique used a four-stranded HG transplant pedicled to the tibia. The functional result (Lysholm knee score and subjective IKDC score), clinical result (KT-1000, Lachman test, joint amplitudes, objective IKDC score), and isokinetic complication occurrence were analyzed at six months and 12 months follow-up. The functional results, clinical parameters, and complications were analyzed at 30 months follow-up. The comparison of the variables with the various regressions was carried out by a Wilcoxon sign test., Results: Twenty-one patients were reviewed at six, nine, 12, and 30 months. The mean Lysholm knee score was 90/100 at six months, 96/100 at one year, and 95/100 at 30 months. The mean subjective IKDC score was 77/100 and 89/100 at six and 12 months, and 91/100 at 30 months. The mean difference in laxity compared with the healthy knee was 1.4 mm at six months, 1.9 mm at 12 months, and 2 mm at 30 months. The objective IKDC score was A or B for all patients at 12 and 30 months. The average quadriceps strength deficit decreased from 27 to 16% between six and 12 months post-operative (p = 0.0091) and the average flexor deficit from 23 to 12% (p = 0.0084). No complications were identified., Conclusion: The abovementioned technique allows reaching functional, clinical, and isokinetic results comparable with the standard techniques while preserving the mechanical and biological interest of tibial insertion.

Purpose: Clinicians have different techniques and varying levels of experience with the pivot shift test, introducing variability into its performance. The purpose of this study was to evaluate the influence of teaching and repetition on the success rate and anterior translation of the lateral knee compartment during the pivot shift test in a cadaveric ACL injury model., Methods: Twenty-five participants (five each of medical students, orthopaedic surgery residents, physical therapists, athletic trainers, sports medicine fellows) were recruited and a senior orthopaedic surgeon served as gold standard examiner. Each participant performed 20 pivot shift tests on lower extremity cadaveric specimens with ACL deficiency and lateral meniscectomy: 5 prior to education (baseline), 10 after watching an instructional video (passive teaching), and 5 after an interactive education session (active teaching). The anterior translation of the lateral knee compartment was recorded during each pivot shift test using electromagnetic tracking system., Results: For medical students and orthopaedic surgery residents, significant improvement in success rate was found when compared to baseline (12% and 24%, respectively) after both passive (36% and 60%, respectively) and active teaching (52% and 72%, respectively) (p < 0.5). Medical students and residents were the only participants that independently achieved significant increases in anterior translation of the lateral knee compartment, each tripling the respective baseline value (p < 0.5). In the entire study population, significant increases in anterior translation of the lateral knee compartment and success rate of the pivot shift test were seen with continuous repetition (p < 0.5). However, the standard deviation of anterior translation of the lateral knee compartment was more than twice the gold standard examiner's standard deviation, indicating a high degree of variability., Conclusion: Teaching of the pivot shift test plays a major role in the development of a proper technique. However, variability persisted despite teaching and repetition. New methods may be needed to improve the teaching of the pivot shift test.

Cranial cruciate ligament disease (CCLD) is a complex trait. Ten measurements were made on orthogonal distal pelvic limb radiographs of 161 pure and mixed breed dogs with, and 55 without, cranial cruciate partial or complete ligament rupture. Dogs with CCLD had significantly smaller infrapatellar fat pad width, higher average tibial plateau angle, and were heavier than control dogs. The first PC weightings captured the overall size of the dog's stifle and PC2 weightings reflected an increasing tibial plateau angle coupled with a smaller fat pad width. Of these dogs, 175 were genotyped, and 144,509 polymorphisms were used in a genome-wide association study with both a mixed linear and a multi-locus model. For both models, significant (pgenome <3.46×10-7 for the mixed and< 6.9x10-8 for the multilocus model) associations were found for PC1, tibial diaphyseal length and width, fat pad base length, and femoral and tibial condyle width at LCORL, a known body size-regulating locus. Other body size loci with significant associations were growth hormone 1 (GH1), which was associated with the length of the fat pad base and the width of the tibial diaphysis, and a region on CFAX near IRS4 and ACSL4 in the multilocus model. The tibial plateau angle was associated significantly with a locus on CFA10 in the linear mixed model with nearest candidate genes BET1 and MYH9 and on CFA08 near candidate genes WDHD1 and GCH1. MYH9 has a major role in osteoclastogenesis. Our study indicated that tibial plateau slope is associated with CCLD and a compressed infrapatellar fat pad, a surrogate for stifle osteoarthritis. Because of the association between tibial plateau slope and CCLD, and pending independent validation, these candidate genes for tibial plateau slope may be tested in breeds susceptible to CCLD before they develop disease or are bred., Competing Interests: The authors have declared that no competing interests exist.

We aimed to investigate how increased or decreased femoral antetorsion would affect the biomechanics of the knee in an anterior cruciate ligament (ACL)-deficient cadaveric model. We hypothesized that external or internal rotation of the distal femur, achieved through a femoral osteotomy, would affect the magnitude of tibiofemoral translation and rotation. Navigated measurements of tibiofemoral translation and rotation during the anterior drawer, Lachman, and pivot shift tests were performed on six whole-body cadaveric specimens in each of the following four conditions: native, ACL-deficient knee, ACL-deficient knee and 20-degree internal distal femur rotation, and ACL-deficient knee and 20-degree external distal femur rotation. Increased femoral antetorsion significantly reduced anterior tibial translation in the ACL-deficient knee during the anterior drawer, Lachman, and pivot shift tests ( p  < 0.05). Conversely, decreasing femoral antetorsion resulted in an increase in anterior tibial translation in the anterior drawer (nonsignificant), Lachman ( p  < 0.05), and pivot shift ( p  < 0.05) tests. Internally rotating the distal femur significantly reduced the magnitude of tibial rotation during the pivot shift test in the ACL-deficient knee ( p  < 0.05), whereas external rotation of the distal femur significantly increased tibial rotation ( p  < 0.05). The magnitude of femoral antetorsion affects tibiofemoral translation in an ACL-deficient cadaveric mode. Internally rotating the distal femur 20 degrees reduced the magnitude of tibial translation and rotation similar to that of the native knee, whereas externally rotating the distal femur aggravated translational and rotational instability., Competing Interests: None., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Functional knee braces are frequently prescribed by physicians to ameliorate the function of individuals with anterior cruciate ligament (ACL) injuries. These braces have been shown in the literature to potentially enhance knee stability by augmenting muscle activation patterns and the timing of muscle response to perturbations. However, very few techniques are available in the literature to quantify how those modifications in lower-limb muscle activity influence stability of the knee. The aim of the present study was to quantify the effect of an off-the-shelf functional knee brace on muscle contributions to knee joint rotational stiffness in ACL-deficient and ACL-reconstructed patients. Kinematic, electromyography, and kinetic data were incorporated into an electromyography-driven model of the lower extremity to calculate individual and total muscle contributions to knee joint rotational stiffness about the flexion-extension axis, for 4 independent variables: leg condition (contralateral uninjured, unbraced ACL injured, and braced ACL injured); knee flexion (5°-10°, 20°-25°, and 30°-35°); squat stability condition (stable and unstable); and injury status (ACL deficient and ACL reconstructed). Participants had significantly higher (P < .05, η2 = .018) total knee joint rotational stiffness values while wearing the brace compared with the control leg. A 2-way interaction effect between stability and knee flexion (P < .05, η2 = .040) for total joint rotational stiffness was also found.

Background: Although anterior cruciate ligament (ACL) tear-prevention programs may be effective in the (secondary) prevention of a subsequent ACL injury, little is known, yet, on their effectiveness and feasibility. This study assesses the effects and implementation capacity of a secondary preventive motor-control training (the Stop-X program) after ACL reconstruction., Methods and Design: A multicenter, single-blind, randomized controlled, prospective, superiority, two-arm design is adopted. Subsequent patients (18-35 years) with primary arthroscopic unilateral ACL reconstruction with autologous hamstring graft are enrolled. Postoperative guideline rehabilitation plus Classic follow-up treatment and guideline rehabilitation plus the Stop-X intervention will be compared. The onset of the Stop-X program as part of the postoperative follow-up treatment is individualized and function based. The participants must be released for the training components. The endpoint is the unrestricted return to sport (RTS) decision. Before (where applicable) reconstruction and after the clearance for the intervention (aimed at 4-8 months post surgery) until the unrestricted RTS decision (but at least until 12 months post surgery), all outcomes will be assessed once a month. Each participant is consequently measured at least five times to a maximum of 12 times. Twelve, 18 and 24 months after the surgery, follow-up-measurements and recurrence monitoring will follow. The primary outcome assessement (normalized knee-separation distance at the Drop Jump Screening Test (DJST)) is followed by the functional secondary outcomes assessements. The latter consist of quality assessments during simple (combined) balance side, balance front and single-leg hops for distance. All hop/jump tests are self-administered and filmed from the frontal view (3-m distance). All videos are transferred using safe big content transfer and subsequently (and blinded) expertly video-rated. Secondary outcomes are questionnaires on patient-reported knee function, kinesiophobia, RTS after ACL injury and training/therapy volume (frequency - intensity - type and time). All questionnaires are completed online using the participants' pseudonym only. Group allocation is executed randomly. The training intervention (Stop-X arm) consists of self-administered home-based exercises. The exercises are step-wise graduated and follow wound healing and functional restoration criteria. The training frequency for both arms is scheduled to be three times per week, each time for a 30 min duration. The program follows current (secondary) prevention guidelines. Repeated measurements gain-score analyses using analyses of (co-)variance are performed for all outcomes., Trial Registration: German Clinical Trials Register, identification number DRKS00015313 . Registered on 1 October 2018.

Purpose: To assess the relationship between the KiRA triaxial accelerometer and the KT-1000 measurements in the intact, anterior cruciate ligament (ACL) deficient, and ACL reconstructed knee joint for the quantification of the Lachman test. Moreover, the intra- and inter-examiner repeatability of the KiRA device will be determined. It was hypothesized that the side-to-side difference of the anterior tibial translation as measured by the KiRA device would be equivalent to the one measured by the KT-1000 during the Lachman test., Methods: Sixty patients were divided into three groups and have been prospectively included in the present study. Group&#95;A composed of 20 patients with a diagnosis of an isolated ACL tear. Group&#95;B composed of 20 patients who underwent ACL reconstruction with a Single-Bundle Lateral Plasty (SBLP) technique with at least 20 years of follow-up. Group&#95;C was the control group and included 20 patients with no history of ACL lesion. Lachman test has been performed at manual-maximum load on both sides, the involved and the contralateral and analyzed with the two different devices., Results: The KiRA device in terms of side-to-side difference resulted not statistically different from the measurement of the KT-1000 arthrometer for the three study groups (n.s): Group&#95;A: (4 ± 2 mm KiRA, 4 ± 2 mm KT1000), Group&#95;B: (4 ± 2 mm KiRA, 4 ± 2 mm KT-1000), Group&#95;C: (4 ± 2 mm KiRA, 4 ± 2 mm KT-1000), an excellent intra- (ICC = 0.88-0.89) and inter-examiner (ICC = 0.79) agreement was found for KiRA measurements., Conclusion: The KiRA (I+, Italy) device offers a valid method to quantify the Lacham test., Level of Evidence: II.

Purpose: To translate, cross-culturally adapt and validate the scale to Lithuanian., Methods: The process of translation and cultural adaptation followed the recommendations of international guidelines. All included patients were after unilateral ACL reconstruction. Study participants completed Tegner Activity Scale, IKDC and ACL-RSI-Lt questionnaires. Reliability, construct validity and internal consistency were measured., Results: Study included sixty-five patients after ACL reconstruction: mean age 25.55 ± 6.77, mean height 180.91 ± 11.78 cm, mean weight 79.12 ± 14.88 kg and mean BMI 24.01 ± 2.90. The ACL-RSI-Lt showed excellent internal consistency (Cronbanch's alpha 0.94). Scale scores were correlated with IKDC score (r = 0.637, p < 0.001) and IKDC subscales (r = 0.530-0.581, p < 0.001) and Tegner activity score (r = 0.303-0.493, p < 0.001). Tegner activity score before injury was significantly higher than after ACLR (6.95 ± 1.49 vs. 6.1 ± 1.37, p < 0.001)., Conclusions: The ACL-RSI is successfully translated into Lithuanian (ACL-RSI-Lt). It is valid and reliable scale to evaluate the psychological impact of returning to sports in Lithuanian patients after ACLR surgery., Competing Interests: The authors have declared that no competing interests exist.

Background: Pretension of the viscoelastic graft by cyclic knee motion has been confirmed to decrease the graft creep and improve the outcome of anterior cruciate ligament (ACL) reconstruction. The purpose of the present study was to investigate the effect of cyclic knee motion on the elongation of the four-strand hamstring tendon autograft in situ and to explore the stable level cycle, in which the tendon length achieved a stable level., Methods: The study was performed with 53 consecutive patients undergoing transtibial ACL reconstruction with four strand hamstring tendon from Aug 2013 to Apr 2015. 43 males and 10 females were included with mean age of 29 ± 10 years. The pretension of the tendons was operated by cyclical knee motion ranging from 0 to 110°after the femoral fixation with Endo-button. The tendon length after 10, 20, 30 and 40 cycles was measured respectively and compared by repeated measure ANOVA. Then multivariate logistic regression was used to investigate the effect of the patients' parameters (age, gender, height, body weight, tendon length, etc.) on the elongation of the graft and the stable level cycle., Results: The mean lengthening of the graft at 10, 20, 30 and 40 times was 3.0 ± 1.4 mm, 4.3 ± 1.5 mm, 4.8 ± 1.7 mm and 4.8 ± 1.8 mm respectively. No significant correlation was found between the elongation and the patients' parameters. There was significant difference of the tendon length from 0 to 30 cycles (F = 264.8, df = 1.95, p<0.001). However, the tendon length achieved a stable level after 30 cycles and the median elongation from 30 cycles to 40 cycles was 0 (0-1) mm with no significant difference (F = 2.039, p = 0.159). The male and female tendon length achieved to a stable level at 20 cycles and 30 cycles respectively but with no significant difference (p = 0.074)., Conclusions: The four-strand hamstring tendon was elongated after cyclic knee motion and the elongation achieved a stable level after 30 cycles for the transtibial technique. Both of the tendon elongation and the stable level cycle were not correlated with patients' gender, age, preoperative duration, graft diameter and length.

Objectives: To evaluate postural regulation and stability among patients who underwent anterior cruciate ligament reconstruction (ACLR) and rehabilitation over a two-year follow-up period., Design: Longitudinal; SETTING: Biomechanics laboratory; PARTICIPANTS: 30 ACLR patients (32.0 ± 12.2 years, 14 males) with isolated ACL rupture., Main Outcome Measures: Postural regulation was tested before ACLR, as well as at six-weeks, twelve-weeks, six-months, one-year and two-years post-ACLR and standardized rehabilitation. Postural regulation was measured for stability indicator (ST), weight distribution index (WDI), synchronization (foot coordination) and sway intensities (postural subsystems)., Results: Significant time effects (pre-vs. two-years postoperative) were found for WDI (η p 2  = 0.466), synchronization (η p 2  = 0.368), mediolateral weight distribution (η p 2  = 0.349), ST (η p 2  = 0.205), visual/nigrostriatal systems (η p 2  = 0.179) and peripheral-vestibular system (η p 2  = 0.102). The largest difference (preoperative: η p 2  = 0.180) to the matched sample was calculated for WDI. The most significant differences to the matched sample were observed for ST (preoperative: η p 2  = 0.126; six-weeks postoperative: η p 2  = 0.103) and WDI (preoperative: η p 2  = 0.180; six-weeks postoperative: η p 2  = 0.174)., Conclusion: ACLR and rehabilitation influence postural subsystems, postural stability, weight distribution and foot synchronization. Normalization of mediolateral weight distribution requires one year following ACLR. The ACLR leads to a suppression of the somatosensory and cerebellar system which was compensated by a higher activity of the visual and nigrostriatal systems., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Objective: The objective was to compare muscle activation and knee mechanics during gait between participants with non-traumatic knee osteoarthritis (OA), post-traumatic knee OA, and healthy adults., Design: Participants with non-traumatic knee OA (n = 22), post-traumatic knee OA (n = 19), and healthy adults (n = 22) completed gait trials for this observational, cross-sectional study. Post-traumatic OA group had a history of traumatic anterior cruciate ligament (ACL) rupture. Surface electromyography (EMG) measured activation of seven lower extremity muscles. Motion capture cameras and force plates measured motion and force data. Principal component analysis (PCA) determined waveform characteristics (principal components) from EMG, knee angle, and knee external moment waveforms. Analysis of variance (ANOVA) examined group differences in principal component scores (PC-scores). Regression analyses examined if a variable that coded for OA group could predict PC-scores after accounting for disease severity, alignment, and lateral OA., Results: There was lower gastrocnemius EMG amplitudes (P < 0.01; ANOVA) in the post-traumatic OA group compared to healthy group. Non-traumatic OA group had higher vastus lateralis, vastus medialis, and rectus femoris EMG compared to post-traumatic OA group (P = 0.01 to 0.04) in regression analyses. Also, non-traumatic OA group had higher and prolonged lateral hamstring EMG compared to healthy (P = 0.03; ANOVA) and post-traumatic OA (P = 0.04; regression) groups respectively. The non-traumatic OA group had lower knee extension (P < 0.05) and medial rotation (P < 0.05) moments than post-traumatic and healthy groups., Conclusions: Muscle activation and knee mechanics differed between participants with non-traumatic and post-traumatic knee OA and healthy adults. These OA subtypes had differences in disease characteristics that may impact disease progression., (Copyright © 2019 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Background: The Lower Extremity Functional Scale evaluates the functional status of patients that have lower extremity conditions of musculoskeletal origin. Regional Arabic dialects often create barriers to clear communication and comparative research. We aimed to cross-culturally adapt the Lower Extremity Functional Scale in modern standard Arabic that is widely used and understood in the Middle East and North Africa region, and assess its psychometric properties., Methods: Cross-cultural adaptation followed a combination of recommended guidelines. For psychometric evaluation 150 patients with anterior cruciate ligament injury and 65 asymptomatic individuals were recruited. All measurement properties as indicated by the Consensus-based Standards for the selection of health status Measurement Instruments recommendations were evaluated, including content-relevance analysis, structural validity, longitudinal reproducibility, anchor- and distribution-based methods of responsiveness, as well as the longitudinal pattern of change of Lower Extremity Functional Scale in anterior cruciate ligament injured patients' functional status., Results: The questionnaire presented excellent internal consistency (α = 0.96), reliability (0.80-0.98), and good convergent validity (ρ = 0.85). For reproducibility testing: minimal detectable change was 9.26 points; for responsiveness assessment: minimal clinically important difference was 9 points and presented moderate effect sizes (Glass'Δ = 0.71, Cohen's d = 0.81). Its unidimensionality was not confirmed and an exploratory factor analysis indicated a 2-factor solution explaining 78.1% of the variance., Conclusion: The Arabic Lower Extremity Functional Scale presented acceptable psychometric properties comparable to the original version. The Arabic version of Lower Extremity Functional Scale can be used in research and clinical practice to assess the functional status of Arabic-patients suffering an anterior cruciate ligament injury., Competing Interests: The authors have declared that no competing interests exist.

The presentation and clinical course of mucoid degeneration of the anterior cruciate ligament (MD-ACL) are poorly documented within the literature. Subsequently, it is under-diagnosed and the optimal management strategy remains ill-defined. Here, we characterize the syndrome associated with MD-ACL and compare the natural clinical course with the outcomes of arthroscopic management. Thirty-one patients with radiological features of MD-ACL over a 2-year period had their clinical notes retrospectively reviewed. Seven patients underwent arthroscopic debridement of the ACL for MD. These were followed up for a minimum of 2 years and an average of 2.8 years from surgery. The remainder were managed conservatively ( n  = 24) and were followed up for a minimum of 2 years and an average of 4.0 years. The notch width index (NWI) and associated pathology was noted. Primary outcome measures were presence of knee pain and use of analgesia. Secondary outcome measures were the Oxford and Lysholm knee scores. The most commonly reported symptoms were posterior knee pain (77.4%) and limitation of terminal flexion (58.1%). All patients who underwent arthroscopic debridement were pain and analgesia free at follow-up. Of the patients who did not undergo arthroscopic surgery, three patients had knee replacement surgery and three were lost to follow-up. The remaining patients, 14/18 (77.8%), reported knee pain and regular analgesia use at follow-up, which was significantly more than the arthroscopic debridement group ( p  < 0.01). The knee scores were significantly better in the arthroscopic debridement group at follow-up (Oxford knee score: 45 vs 34; Lysholm: 92 vs 67; p  < 0.01). Furthermore, the postoperative improvement in the Oxford knee and Lysholm scores compared with preoperatively was 12.1 and 31.8 points, respectively ( p  < 0.01). The NWI was increased in patients with mild-to-severe osteoarthritis (0.266 vs 0.273; p  < 0.05). MD-ACL should be considered in patients who report posterior knee pain, limitation of terminal flexion, and it can be associated with other knee pathologies. MD-ACL can be successfully managed with arthroscopic radio frequency debulking with improvement in quality of life at follow-up., Competing Interests: None declared., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Background: Protective knee braces are used for rehabilitation or prevention. Due to poor patient compliance or slippage, the brace might be misaligned with the knee axis., Objectives: Does a misaligned knee brace stress the anterior cruciate ligament?, Study Design: It is an experimental study., Methods: A strain sensor was implanted on the anterior cruciate ligament in eight limbs. The limbs were mounted in a knee simulator, muscle forces were applied and a cyclic motion from 10° to 60° flexion was performed under three conditions: unbraced, braced and with a misaligned brace., Outcome Measures: The outcome measures were anterior cruciate ligament strain and three-dimensional kinematics of the knee joint., Results: The correctly aligned brace significantly reduced the anterior cruciate ligament strain at 10° compared to the unbraced condition from 0% to -1.54% (standard deviation = 1.4). The misaligned brace neutralised the effect of bracing to -0.06% (standard deviation = 1.1) anterior cruciate ligament strain. At 60° flexion angle, bracing had no statistically significant effect on the anterior cruciate ligament strain compared to the unbraced knee: -2.58% (standard deviation = 0.8) versus -1.64% (standard deviation = 1.0). The anterior cruciate ligament in the misaligned braced knee at 60° flexion with a strain of -1.1% (standard deviation = 0.9) was significantly more stressed than in the correctly aligned condition. An effect of bracing on knee kinematics was not detected., Conclusion: A correctly aligned knee brace reduced anterior cruciate ligament strain. By contrast, a misaligned brace tended to increase the anterior cruciate ligament strain compared to the unbraced knee., Clinical Relevance: The correct alignment of the brace was identified as a key factor decisively influencing the effectiveness of bracing.

Background: Osteoarthritis (OA) of the knee joint is a common disease accompanied by pain and impaired mobility. Despite some recent concerns on the lack of correlation between the medial load and the knee adduction moment (KAM), KAM is routinely considered as a surrogate measure of medial load and hence a marker where its reduction is the main focus of preventive and treatment interventions., Research Question: Determine the relative sensitivity of the tibiofemoral medial-lateral contact load partitioning to changes in the knee adduction angle (KAA) versus KAM., Methods: Using a lower extremity hybrid musculoskeletal (MS) model driven by gait kinematics and kinetics, we compute here in asymptomatic subjects the sensitivity of the knee joint biomechanical response (muscle and ligament forces) in general and medial/lateral load partitioning in particular to the relative changes in the reported KAA versus changes in reported KAM (both by one standard deviation)., Results: As KAA increased (at constant KAM), so did the passive moment resistance of the knee joint which as a result and at all stance periods substantially reduced forces in lateral hamstrings while increasing those in medial hamstrings. At 25% and 75% stance as two highly loaded periods of gait, the drop in KAA (from + SD to -SD while at constant KAM) drastically reduced the medial contact force by 44% and 30% and the medial over lateral contact load and area ratios by 92% and 79% as well as 64% and 51%, respectively. In contrast, the equivalent alterations in KAM (by ± SD at constant KAA) had lower and less consistent effects (<7%) showing much smaller sensitivity to changes in KAM alone. Ligament forces altered at various stance periods with inconsistent trends; peak values of 418 N in the anterior cruciate ligament (90% carried by the posterolateral bundle) and 1056 N in the patellar tendon were computed both at 25% stance and minimum KAA., Significance: These findings indicate a poor correlation between KAM and tibiofemoral load distribution suggesting instead that KAA and knee alignment should be in focus as the primary marker of knee joint load partitioning and associated prevention and treatment interventions., (Crown Copyright © 2019. Published by Elsevier B.V. All rights reserved.)

Unicompartmental knee arthroplasty (UKA) in anterior cruciate ligament deficiency (ACLD) has been debated for decades after the development of highly cross-linked polyethylene. This study aims to evaluate the effect of posterior tibial slope on restoring adequate knee stability and flexion after UKA in patients with ACLD. A total of 15 fresh cadaveric knees were divided into three groups: intact ACL, partial ACLD, and complete ACLD. Fixed-bearing UKAs including 3-D-printed tibial inserts with the slopes ranging from 3° to 12° were performed using computer-assisted navigation. Blinded evaluation of knee motion and anterior knee translation with knees flexed 20° and 90° was conducted using KT-arthrometry and stress radiography. A 1° slope increase translated the knees anteriorly by 0.85 mm and 0.76 mm in 20° and 90° of knee flexion for a complete ACLD ( R = 0.7 and 0.8, respectively, p < 0.001) compared to 0.5-0.6 mm for the normal and partial ACLD groups, respectively. Setting a slope of 5-8° of UKA for an intact ACL maintained both the stability and the motion of native knees. No significant changes of knee translation and flexion ability were observed after leveling the slopes at 5-7° and 5-6° for partial and complete ACLD, respectively ( p > 0.05 for all comparisons). In conclusion, UKA in complete ACLD knees is challenging since 1° of slope change nearly doubles the degree of knee translation compared to ACL-intact knees. The optimum posterior tibial slopes for fixed-bearing UKA patients with partial and complete ACLD are 5-7° and 5-6°, respectively.

Knee osteoarthritis (KOA) is associated with muscle weakness, but it is unclear which structures are involved in the muscle changes. This study assessed morphological alterations and the expression of genes and proteins linked to muscular atrophy and neuromuscular junctions (NMJs) in KOA, induced by anterior cruciate ligament transection (ACLT) in rats. Two groups of rats were assessed: control (without intervention) and KOA (ACLT surgery in the right knee). After 8 weeks, quadriceps, tibialis anterior (TA) and gastrocnemius muscles were analyzed (area of muscle fibers, NMJ, gene and protein expression). KOA group showed atrophy in quadriceps (15.7%) and TA (33%), with an increase in atrogin-1 and muscle RING-finger protein-1 (MuRF-1). KOA group showed quadriceps NMJ remodeling (reduction area and perimeter) and decrease in NMJ diameter in TA muscle. The expression of nicotinic acetylcholine receptor (nAChR) γ-nAChR increased and that of α-nAChR and muscle specific tyrosine kinase (MuSK) declined in the quadriceps, with a decrease in ε-nAChR in TA. MuRF-1 protein expression increased in quadriceps and TA, with no changes in neural cell adhesion molecule (NCAM). In conclusion, ACLT-induced KOA promotes NMJ remodeling and atrophy in quadriceps and TA muscles, associated with inflammatory signs and changes in muscle gene and protein expression.

Introduction: An anterior cruciate ligament (ACL) injury affects knee proprioception and sensorimotor control and might contribute to an increased risk of a second ACL injury and secondary knee osteoarthritis. Therefore, there is a growing need for valid, reliable and responsive knee proprioception tests. No previous study has comprehensively reviewed all the relevant psychometric properties (PMPs) of these tests together. The aim of this review protocol is to narrate the steps involved in synthesising the evidence for the PMPs of specific knee proprioception tests among individuals with an ACL injury and knee-healthy controls., Methods and Analysis: The Preferred Reporting Items for Systematic reviews and Meta-Analyses will be followed to report the review. A combination of four conceptual groups of terms-(1) construct (knee proprioception), (2) target population (healthy individuals and those with an ACL injury managed conservatively or with a surgical reconstruction), (3) measurement instrument (specific knee proprioception tests) and (4) PMPs (reliability, validity and responsiveness)-will be used for electronic databases search. PubMed, AMED, CINAHL, SPORTDiscus, Web of Science, Scopus, the Cochrane Central Register of Controlled Trials and ProQuest will be searched from their inception to November 2018. Two reviewers will independently screen titles, abstracts and full text articles, extract data and perform risk of bias assessment using the updated COnsensus-based Standards for the selection of health Measurement INstruments risk of bias checklist for the eligible studies. A narrative synthesis of the findings and a meta-analysis will be attempted as appropriate. Each PMP of knee proprioception tests will be classified as 'sufficient', 'indeterminate' or 'insufficient'. The overall level of evidence will be ascertained using an established set of criteria., Ethics and Dissemination: Ethical approval or patient consent is not required for a systematic review. The review findings will be submitted as a series of manuscripts for peer-review and publication in scientific journals., Prospero Registration Number: CRD42018108014., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Injuries of the anterolateral ligament (ALL) are fairly common in patients with ruptures of the anterior cruciate ligament (ACL). Before considering repair or reconstruction of the ALL, the lack of knowledge with regard to the biomechanical behavior of this ligament must be considered. The purpose of this study was to analyze the strain of the ALL induced by tibial internal rotation at different flexion angles and find out the strain distribution features., Methods: The ALLs of ten fresh-frozen cadaver knees were dissected. All specimens underwent tibial internal rotation from 0° to 25° at 30°, 60°, 90°, and 120° of knee flexion. Strain distribution of the ALL during internal rotation was recorded by digital image correlation (DIC). The overall strain and sub-regional strain were measured., Results: The strain of the ALL increased with increasing tibial internal rotation. With 25° of internal rotation, the overall strain at each flexion angle was 12.89 ± 2.73% (30°), 15.32 ± 2.50% (60°), 18.94 ± 2.34% (90°), and 20.10 ± 3.27% (120°). The sub-regional strain was significantly different at all flexion angles. The strain of the distal 1/3 of the ALL was the greatest, followed by the middle 1/3, while the proximal 1/3 was the smallest (all P < 0.001)., Conclusion: The ALL resisted internal rotation of the tibia by becoming more tense with increasing rotation. A significantly high strain was observed in the distal portion near the tibial insertion site of the ALL, which may suggest that this region is prone to injury with excessive internal rotation., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Background: Despite advances in technology, graft rupture rates reported in the literature following anterior cruciate ligament (ACL) surgery range from 1.8% to 18%. Recent anatomical studies have identified a lateral structure, the anterolateral ligament (ALL), as a potential source of residual pivoting following ACL reconstruction. The purpose of this report is to review the history surrounding the ALL and recent anatomic studies, identify its biomechanical and clinical implications, and develop a practical approach to utilizing it during ACL reconstruction., Methods: An extensive review of the historical and current literature surrounding the identification of the ALL, its biomechanical function, reconstruction, and outcomes of ALL reconstruction was performed., Discussion: After the storm of media coverage surrounding the "new ligament" known as the ALL, much attention was focused on cadaveric dissection, biomechanical analysis, and reconstruction of this structure. Several techniques have been described, and currently studies are being performed both retrospectively and prospectively to evaluate the added benefit of ALL reconstruction to the rotational stability of the knee and outcomes after ACL reconstruction., Conclusion: The ALL is a lateral-based structure that provides rotational stability to the knee in the presence of ACL deficiency. Reconstruction of this ligament may provide added benefit to stability and outcomes following ACL reconstruction in certain patient populations. Further randomized controlled trials are needed to elucidate the true benefit of ALL reconstruction and those patients who should undergo this added procedure.

Purpose: To investigate whether single femoral, single tibial tunnel anatomic double-bundle anterior cruciate ligament (ACL) reconstruction is equal to or superior to double femoral, double tibial tunnel ACL double-bundle anatomic reconstruction in terms of restoring the stability and functions of the knee joint., Methods: A prospective clinical study was performed to compare 30 cases of single-tunnel ACL double-bundle anatomic reconstruction to 28 cases of double-tunnel ACL double-bundle anatomic reconstruction, with average follow-up of 36 months. All graft tendons were hamstring tendon autografts. Tunnel placements in all the cases were made anatomically. Clinical results were collected after reconstruction. Graft appearance, meniscus status and cartilage state under arthroscopy were compared and analyzed., Results: Tunnel placements were in the anatomic positions in both groups. On the lateral pivot-shift test performed at 36 months postoperatively, there was no significant difference between groups. Clinical results such as International Knee Documentation Committee score, Tegner activity scale, and range of motion showed no significant differences between the groups. The mean thickness of anteromedial graft was reduced by 10.3% and that of the posterolateral graft was reduced by 11.1% from the original graft thickness evaluated by magnetic resonance imaging. No new meniscal tears were found either group; however, cartilage damage occurred in the double-tunnel group at 39.3%, and this rate was significantly higher than that in the single-tunnel group (10.0%)., Conclusion: Single femoral, single tibial tunnel anatomic double-bundle ACL reconstruction has the same effectiveness as the double femoral, double tibial tunnel in restoring the knee's stability and functions.

Little effort has been directed towards the consequence of an injury on joint angular velocity. We hypothesized that the magnitude of knee joint angular velocity would be decreased after injury. Four injury groups were investigated in an ovine model: (1) anterior cruciate ligament (ACL) and medial collateral ligament (MCL) transection (ACL/MCL Tx) (n = 5), (2) lateral meniscectomy (Mx) (n = 5), (3) partial ACL transection (p-ACL Tx) (n = 5), and (4) partial-ACL and MCL transection (p-ACL/MCL Tx) (n = 5). The magnitude of the angular velocities decreased in the subjects of all groups at multiple points of the gait cycle. The maximum angular velocities during stance and the maximum extension angular velocities during swing were decreased in 15/20 and 17/20 subjects, respectively. There were strong correlations between morphological osteoarthritis scores and the reduction in the maximum extension angular velocities during swing 40 weeks post-p-ACL Tx and 20 weeks post-ACL/MCL Tx. There was no correlation between the decrease of the angular velocity and morphological osteoarthritis scores in the Mx group and the p-ACL/MCL Tx group. The reduction in angular velocity may be a helpful addition as a surrogate measure of OA risk after ACL injury, and could have clinical significance after further investigation in humans.

Purpose: Anterior cruciate ligament (ACL) ruptures are common and are frequently reconstructed using a patellar tendon (PT) autograft. Unfortunately, the time course of PT healing after ACL reconstruction is not particularly well understood. Thus, the primary objective of this study was to use shear wave elastography (SWE) to evaluate the extent to which shear wave speed (SWS) is associated with time after ACL reconstruction., Methods: Longitudinal SWE images were acquired from lateral, central, and medial regions of the PT from two groups: 30 patients who had undergone ACL reconstruction with a PT autograft within the preceding 40 months, and 30 age-matched asymptomatic control subjects. SWE images were acquired at 20° and 90° of passive flexion from both knees. In each subject group, statistical analyses assessed changes in mean SWS with time post-surgery, as well as differences in mean SWS between PT regions and limbs., Results: In the ACL reconstruction patients, mean SWS increased with time post-surgery in the lateral region of the involved knee (p = 0.025) and decreased with time post-surgery in the central region of the contralateral knee (p = 0.022)., Conclusion: The findings suggest that there is an association between the mechanical properties of the PT and time post-surgery in both the involved and contralateral limbs after ACL reconstruction. These changes are likely due to maturation of the donor site tissue and changes in gait/loading patterns following ACL rupture and reconstruction., Level of Evidence: Level II - Prospective Cohort., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The collagen density is not detected in the patellar tendon (PT), posterior cruciate ligament (PCL), and anterior cruciate ligament (ACL) in clinic. We assess the technical feasibility of three-dimension multiecho fat saturated ultrashort echo time cones (3D FS-UTE-Cones) acquisitions for single- and bicomponent T2⁎ analysis of bound and free water pools in PT, PCL, and ACL in clinic. The knees of five healthy volunteers and six knee joint samples from cadavers were scanned via 3D multiecho FS-UTE-Cones acquisitions on a clinical scanner. Single-component fitting of T2⁎ M and bicomponent fitting of short T2⁎ (T2⁎ S ), long T2⁎ (T2⁎ L ), short T2⁎ fraction (Frac&#95; S ), and long T2⁎ fraction (Frac&#95; L ) were performed within tendons and ligaments. Our results showed that biexponential fitting was superior to single-exponential fitting in PT, PCL, and ACL. For knee joint samples, there was no statistical difference among all data in PT, PCL, and ACL. For volunteers, all parameters of bicomponent fitting were statistically different across PT, PCL, and ACL, except for T2⁎ S , T2⁎ L , and T2⁎ M resulting in flawed measurements due to the magic angle effect. 3D multiecho FS-UTE-Cones acquisition allows high resolution T2⁎ mapping in PT, PCL, and ACL of keen joint samples and PT and PCL of volunteers. The T2⁎ values and their fractions can be characterized by bicomponent T2⁎ analysis that is superior to single-component T2⁎ analysis, except for ACL of volunteers.