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Transtibial pullout repair yields beneficial clinical outcomes in patients with medial meniscus (MM) posterior root tear. However, the relationship between repaired meniscal root healing status and postoperative clinical outcomes remains unclear. We aimed to evaluate changes in articular cartilage damage and clinical scores after pullout repair using two simple stitches (TSS). Thirty-three patients who underwent pullout repair using TSS were assessed. Healing status was assessed by a semi-quantitative second-look arthroscopic scoring system comprising three evaluation criteria (width of bridging tissues, stability of the repaired root, and synovial coverage), 1 year postoperatively. MM medial extrusion (MMME) and cartilage damage were assessed preoperatively and 1 year postoperatively. The medial compartment was divided into 8 zones (A-H) for comparison of preoperative and 1-year postoperative cartilage damage. Clinical outcomes were evaluated using the Knee Injury and Osteoarthritis Outcome score, Lysholm score, International Knee Documentation Committee scores, and visual analogue scale pain score. Although cartilage damage did not aggravate significantly in most medial compartment areas, MMME progressed at 1 year postoperatively. No statistical differences were observed in cartilage damage between the central-to-medial area of the medial femoral condyle and the medial tibial plateau area at 1 year postoperatively. Regarding semi-quantitative healing scores, the stability score was significantly correlated with the International Cartilage Repair Society grade at 1 year postoperatively. All 1-year and 2-year clinical scores significantly improved compared with the preoperative scores. Regarding TSS repair, stability of repaired meniscal root negatively correlated with cartilage damage in the medial compartment loading area. All 1-year and 2-year clinical scores significantly improved than those of the preoperative scores. Achieving MM stability is crucial for suppressing cartilage degeneration. IV case series study. [ABSTRACT FROM AUTHOR]

Awareness of the value of aquatic exercise (AE) in the postoperative rehabilitation has increased, and several inherent advantages of AE, such as adjustment of both resistance and muscle strengthening parameters makes good rationale for its inclusion in postoperative rehabilitation. This study aimed to determine and compare the benefits of AE and land-based exercise (LBE) on pain, functionality, and quality of life after arthroscopic partial meniscectomy (APM). This randomized controlled study included 30 middle-aged (35–50), physically active patients who were randomized into LBE (n = 15) and AE (n = 15) groups after APM for a degenerative meniscal tear. Visual analogue scale (VAS), Short Form-36 (SF-36), single-leg hop test and Lysholm questionnaire scores in addition to isokinetic muscle strength values were evaluated at baseline, at fourth week immediately after cessation of exercise program and at eighth week follow-up visits. The exercise sessions were conducted in 1-h sessions per day, three days a week for a total of four weeks. Significant improvement was observed in the VAS, single-leg hop test, Lysholm questionnaire, and most of SF-36 subscale scores in both groups at both fourth and eighth follow-ups. Isokinetic dynamometer revealed significant improvement in the peak torque values for extension at angular velocities of 60° and 180° at both follow-ups in the AE group. LBE group showed significant improvement in the peak torque value for extension only at an angular velocity of 60° only at fourth week follow-up. There was no significant difference between groups for any of these parameters at any of the follow-ups. Both AE and LBE programs had significantly improved pain, function, isokinetic muscle strength, and quality of life in patients after APM. Either type of exercise is essential as part of the rehabilitation protocol for good clinical outcomes after APM and should not be neglected (level II). NCT04925726. [ABSTRACT FROM AUTHOR]

Background: Different methods are available to assess the healing status of repaired root for medial meniscus posterior root tears (MMPRT) using second-look arthroscopy. However, few studies are comparing them or validating their usefulness. Therefore, it was hypothesized that the semi-quantitative arthroscopic score might correlate more with 1-year clinical outcomes in patients with MMPRT than the qualitative evaluation.Methods: Data of 61 patients who underwent MMPRT pullout repair and second-look arthroscopy were retrospectively evaluated. The semi-quantitative arthroscopic scoring system was divided into three evaluation criteria: scores from 0 to 10 points include the width of the bridging tissue, stability of the repaired root, and synovial coverage. The qualitative evaluation was classified into 4 status; complete healing, lax healing, scar tissue healing, and failed healing according to the stability and mobility of the repaired root. Multivariate linear regression analyses were used to identify predictors of 1-year postoperative clinical outcomes, including Knee Injury and Osteoarthritis Outcome, Lysholm, or International Knee Documentation Committee scores. Spearman's correlation analysis was used to analyze the correlation between second-look arthroscopic score/qualitative evaluation and 1-year postoperative clinical outcomes. In addition, the optimal cutoff point of semi-quantitative arthroscopic score was determined by receiver operating characteristic (ROC) curve. The Mann-Whitney U test was used to compare clinical outcomes between patients with semi-quantitative arthroscopic scores ≥8 and scores <8.Results: All clinical scores significantly improved at 1 year postoperatively. A good correlation was observed between the semi-quantitative score and clinical scores, but none between qualitative evaluation and clinical scores. The optimal cutoff point of semi-quantitative second-look arthroscopic score was 8 points. Significantly, better clinical outcomes were observed in patients with semi-quantitative scores ≥8 points.Conclusions: All 1-year postoperative clinical scores were significantly improved. The semi-quantitative arthroscopic scores correlate more with 1-year clinical outcomes in patients with MMPRT than the qualitative evaluation.Level Of Evidence: IV case series study. [ABSTRACT FROM AUTHOR]

Purpose: The proximal tibiofibular joint (PTFJ) is easily ignored, although many diseases of the knee are caused by PTFJ injuries. Therefore, studying PTFJ biomechanics is very important. The effects of PTFJ injury on ankle function have been reported. However, few studies have assessed the effects of PTFJ injury on the knee joint. This study was performed to describe the biomechanical effects of PTFJ on the knee joint according to a three-dimensional finite element model.Methods: The knee joint of a healthy volunteer was scanned by CT and MRI. CT and MRI scanning data in DICOM format were imported into Mimics software. Subsequently, 3D models of the normal and PTFJ injured knee, including the bone, cartilage, meniscus and ligament structures were established, and their validity was verified on the basis of available studies in literature. The biomechanical changes in the two knee models under different conditions were compared.Results: The validity of the intact model was verified. No significant difference was observed in tibial mobility in the two models under the conditions of 134 N forward, 10 N·m internal rotation and 10 N·m valgus load. After application of 134 N backward, 10 N·m varus and external rotation load with respect to the tibia, the posterior movement of the tibia and the varus and external rotation angles of the tibia were 3.583±0.892 mm, 4.799±0.092° and 18.963±0.027° in the normal knee model, and 5.127±1.224 mm, 5.277±0.104° and 21.399±0.031° in the PTFJ injury model, respectively, and a significant statistical difference was observed.Conclusions: PTFJ played an important role in maintaining the posterolateral stability of the knee joint and thus deserves more attention in clinical operations. [ABSTRACT FROM AUTHOR]

Background: A meniscal repair is often performed on radial/flap or longitudinal tears of the lateral meniscus (LM) combined with anterior cruciate ligament reconstruction (ACLR). However, it is unknown if meniscal extrusion changes over time after repair. This study evaluated whether meniscal extrusion of the LM is maintained after repair or progresses with time using magnetic resonance imaging (MRI).Methods: Among 574 patients who underwent primary anatomic ACLR, 123 patients followed up for more than 2 years were retrospectively analyzed. Forty patients with concomitant radial/flap tears of the LM (group R), 43 with longitudinal LM tears (group L), and 40 with intact LM (group C, matched-control group) were included. Clinical findings (pain, range of motion, swelling, and anterior laxity), lateral joint space on radiograph, and meniscal extrusion on MRI were assessed. Lateral/posterior meniscal extrusions were examined preoperatively, within 3 weeks after surgery, and at the final follow-up, and the absolute values and relative values (the preoperative values as baseline) were assessed respectively.Results: There were no significant differences in the clinical and roentgenographic findings among the groups. No difference was observed in the relative values within 3 weeks after surgery among three groups, although the absolute values were larger in the repaired groups than in group C. At the final follow-up, however, the lateral extrusion in group L had progressed significantly, compared with that in group C (P = 0.033), while no significant difference was detected in the lateral extrusion between groups R and C (P = 0.177). The posterior extrusion in groups R and L had progressed significantly compared with that in group C (P < 0.001).Conclusions: LM extrusion could not be improved even immediately after meniscal repair, and it progressed laterally and posteriorly for more than 2 years after surgery. [ABSTRACT FROM AUTHOR]

• Low-dose radiation therapy (LDRT) decreased the expression of pro-inflammatory factor MMP13 in chondrocytes. By contrast, COL2 protein expression was increased. • LDRT induced large transcriptomic changes in both chondrocytes/synoviocytes, especially in mitochondrial activities. Gene set variation analysis demonstrated inverted U-shaped response in several categories, such as mitochondrial unfolded protein responses and extracellular matrix interactions. • Growth differentiation factor 15 (GDF15), which is a mitohormetic signaling factor, was increased after LDRT and mediated the anti-inflammatory effects. • OA rats treated with LDRT exhibited a decreased OA severity and reduced osteoclast activity when compared with the no-irradiation group. The use of low-dose radiation therapy (LDRT) for osteoarthritis (OA) are rarely implemented, except in some European regions. Its clinical effects are controversial but little is known about how LDRT affects actual disease progression. We conducted a preclinical study to reveal the potential underlying mechanisms related to its disease modifying abilities. Using primary cultured human chondrocytes and synovium-derived cells obtained from OA patients, the effects of LDRT were measured by quantitative real-time PCR, western blotting, and mRNA sequencing. For in vivo validation, a surgically-induced isolated OA model was used after anterior cruciate ligament transection or surgical destabilization of the medial meniscus. LDRT decreased the expression of pro-inflammatory factor matrix metalloproteinase 13 (MMP13) in chondrocytes. By contrast, collagen type 2 (COL2) protein expression was increased. LDRT induced large transcriptomic changes in both chondrocytes/synoviocytes, especially in mitochondrial activities. Gene set variation analysis demonstrated inverted U-shaped response in several categories, such as mitochondrial unfolded protein responses and extracellular matrix interactions. Growth differentiation factor 15 (GDF15), which is a mitohormetic signaling factor, was increased after LDRT and mediated the anti-inflammatory effects. Aggrecan was increased in synoviocyte's medium and TNF-α was decreased in chondrocyte's medium after LDRT. Conversely, knockdown of GDF15 did not result in decreased MMP13 expression by LDRT. Next, OA rats treated with LDRT exhibited a decreased OA severity when compared with the no-irradiation group at 10 weeks post-surgery (mean OARSI score 3.7 in 0 Gy, 2.8 in 0.5 Gy, and 1.8 in 1 Gy; p = 0.003). Osteoclast activity was significantly reduced in the LDRT group. Taken together, these data show that LDRT could mitigate osteoarthritis progression by exerting its anti-inflammatory effects via mitochondrial function modulation. [ABSTRACT FROM AUTHOR]

• Virtual fracture clinics may reduce unnecessary appointments for benign injuries. • Virtual clinics are the only effective method by which NHS trusts might achieve BOAST standards for 72-hour senior review. • Discharging by letter alone is a valid alternative to traditional telephone discharge from virtual fracture clinic. • A letter-only discharge process could be utilised where staffing limitations are a stumbling block to implementation of virtual fracture clinic. Telephone consult has become the accepted discharge method for virtual fracture clinic (VFC) within the United Kingdom. Telephone consultations are time consuming; many orthopaedic units lack the resources and staff to deliver large numbers of daily telephone consultations which may block the development of an effective VFC. Our study aim was to validate a letter only VFC discharge process for safety and efficacy. A letter only discharge VFC was instigated in response to the COVID-19 pandemic (April 2020). No ethical approval was required, the protocol was designed as a phased service evaluation and improvement project after change in practice. After smaller pilot audits, a comprehensive review of discharges outcomes from the VFC August-September 2021 (Phase 1) and January-March 2022 (Phase 2) was completed. Electronic letters, AE (accident and emergency) attendances and PACS database images (radiography and scans) taken over a 12 month follow up were analysed for failed discharges and adverse outcomes. Of 4810 patients reviewed in VFC, 1140 were discharged (24%). Mean patient age; 35 years (range 2–98), two thirds of patients were adults (>16 years). 116 (10%) returned with symptoms related to their initial presentation usually within the first few weeks via contact with the VFC helpline. Of the returning patients 65 were discharged again with the same advice, 48 underwent further imaging (CT/ MRI/ US scanning). 6 patients (0.5%) underwent surgery for problems relating to the initial injury; 2 knee meniscal repair/debridement, 1 ACL reconstruction, 1 fixation fifth metatarsal non-union, 2 shoulder arthroscopy. All surgeries were performed on elective timescales between 4 and 12 months after injury. Discharging letters detailed rehabilitation and symptom resolution timeframes. Our approach did not result in high return rates or adverse events (unexpected operations) in comparison to published traditional telephone discharge VFC. Units with limited staffing resources wishing to implement a VFC could safely adopt this approach as an alternative to telephone discharge. [ABSTRACT FROM AUTHOR]

Background: Medial meniscus (MM) posterior root repairs lead to favorable clinical outcomes in patients with MM posterior root tears (MMPRTs). However, there are few comparative studies in evaluating the superiority among several pullout repair techniques such as modified Mason-Allen suture, simple stitch, and concomitant posteromedial pullout repair. We hypothesized that an additional pullout suture at the MM posteromedial part would have clinical advantages in transtibial pullout repairs of the MMPRTs. The aim of this study was to compare the clinical usefulness among several types of pullout repair techniques in patients with MMPRTs.Methods: Eighty-three patients who underwent arthroscopic pullout repairs of the MMPRTs were investigated. Patients were divided into three groups using different pullout repair techniques: a modified Mason-Allen suture using FasT-Fix all-inside meniscal repair device (F-MMA, n = 28), two simple stitches (TSS, n = 30), and TSS concomitant with posteromedial pullout repair using all-inside meniscal repair device (TSS-PM, n = 25). Postoperative clinical outcomes and semi-quantitative arthroscopic meniscal healing scores (0-10 points) were evaluated at second-look arthroscopies.Results: No significant differences among the three groups were observed in patient demographics and preoperative clinical scores, except for preoperative Lysholm scores. At second-look arthroscopies, there were no significant differences among the three techniques in postoperative clinical outcomes and meniscal healing scores.Conclusions: This study demonstrated that the TSS-PM pullout repair technique did not show better scores in postoperative clinical outcomes and meniscal healings compared with the F-MMA and TSS techniques. Our results suggest that the concomitant posteromedial pullout suture may have no clinical advantage in the conventional pullout repairs for the patients with MMPRTs. [ABSTRACT FROM AUTHOR]

Background: Medial meniscus posterior root tear (MMPRT) causes medial meniscus extrusion (MME) and leads to subchondral insufficiency fracture of the knee (SIFK). However, the progression of SIFK after MMPRT pullout repair remains unknown. This study aimed to investigate the progression of SIFK and compare clinical outcomes in patients with SIFK to those without SIFK after MMPRT pullout repair. We hypothesized that the progression of SIFK would be prevented by MMPRT pullout repair, and clinical outcomes would improve in all patients.Methods: The SIFK grade (1-4) was evaluated using T2-fat suppression magnetic resonance imaging. Thirty-eight patients without SIFK (n = 22) and with low-grade SIFK (1 and 2; n = 16) who underwent MMPRT pullout repair were included. Preoperative factors, such as the duration from injury to the time of magnetic resonance imaging/surgery (weeks), femorotibial angle (degree), MME (mm), and clinical outcomes were evaluated, as well as the progression of SIFK.Results: SIFK was identified in only 9 patients (grade 1) postoperatively. Significantly improved clinical outcomes were observed in all patients. Preoperative femorotibial angle, MME, and duration from injury to the time of magnetic resonance imaging/surgery were 177.1 ± 1.5°, 3.2 ± 1.6 mm, and 6.4 ± 7.0/10.1 ± 7.5 weeks, respectively. No significant difference in preoperative factors and clinical outcomes was observed between patients with SIFK and those without SIFK.Conclusions: MMPRT pullout repair prevented the progression of low-grade SIFK and improved clinical outcomes in all patients, although bone contusions (grade 1 SIFK) were not completely healed within 1 year. MMPRT pullout repair could be a good treatment option for optimizing clinical outcomes in patients with low-grade SIFK. [ABSTRACT FROM AUTHOR]

Background: Severe chondral lesions and varus knee alignment are associated with poor outcomes following transtibial pullout repair for medial meniscus posterior root tears and meniscus tear is strongly associated with body mass index. The prognostic factors in well-aligned knees (femorotibial angle < 180°) with mild chondral lesions are unknown. Therefore, we investigated the prognostic factors in these patients. We hypothesized that high body mass index would lead to poor clinical outcomes following pullout repair of medial meniscus posterior root tears.Methods: We retrospectively reviewed the files of 28 patients who had undergone pullout repair of medial meniscus posterior root tears between October 2016 and December 2017. We recorded the baseline characteristics (age, gender, height, weight, and body mass index) and the time between injury and surgery. We recorded the International Knee Documentation Committee scores, Knee injury and Osteoarthritis Outcome Scores, and pain visual analog scale scores. Using magnetic resonance imaging preoperatively and 1 year after surgery, we measured the medial meniscus body width and absolute and relative medial meniscus extrusion. Pearson correlation and multivariate linear regression analyses were used to assess potential associations between these factors and clinical outcomes.Results: Age positively correlated (coefficient = 0.49, P < 0.01) and body mass index negatively correlated with the postoperative International Knee Documentation Committee score (coefficient = -0.64, P < 0.01). In multivariate linear regression analysis, body mass index was a significant factor leading to poor postoperative International Knee Documentation Committee score (R2 = 0.29, P < 0.05).Conclusions: Body mass index > 30 kg/m2 is a risk factor for unfavorable clinical outcomes following pullout repair of medial meniscus posterior root tears in well-aligned knees.Level Of Evidence: III, Comparative retrospective study. [ABSTRACT FROM AUTHOR]

Background: Medial meniscus (MM) posterior root repairs show favorable clinical outcomes in patients with MM posterior root tears (MMPRTs). However, there is no useful magnetic resonance imaging (MRI) finding to determine a functionally good meniscal healing following MM posterior root repairs. We hypothesized that a characteristic postoperative MRI finding can predict a good meniscal healing following pullout repairs. The aim of this study was to investigate a clinical usefulness of several MRI findings for estimating an actual meniscal healing following MMPRT repairs.Methods: Fifty eight patients who had a posteromedial painful popping of the injured knee and underwent an arthroscopic pullout repair for the MMPRT were included. Arthroscopic meniscal healing was assessed according to the Furumatsu scoring system at 1 year postoperatively. We evaluated postoperative MRI-based meniscal healing using signal intensity, continuity, suspension bridge-like sign of the MM posterior root, and MM medial extrusion on coronal images. Postoperative clinical outcome evaluations were performed at second-look arthroscopy.Results: Twenty three patients showed good arthroscopic healing scores (≥7 points). Thirty five patients had moderate/poor arthroscopic healing scores (<7 points). At 1-year follow-up period, clinical outcome scores were significantly higher in the good healing group than in the moderate/poor healing group. A characteristic meniscal shape, termed "suspension bridge sign", was highly observed in the good meniscal healing group (83%) compared with in the moderate/poor healing group (26%, P < 0.001). High signal intensity and continuity of the MM posterior root and MM medial extrusion showed no differences between both groups.Conclusions: Our study demonstrated that the MRI-based suspension bridge sign can predict an arthroscopically favorable meniscal healing following the MM posterior root repair. The suspension bridge-like MRI finding of the MM would be a useful indicator to evaluate the actual meniscal healing in patients who underwent pullout repairs for MMPRTs. [ABSTRACT FROM AUTHOR]

This study focuses on the relationship between meniscectomy and osteochondral junction health, and their integrity on cartilage lubrication. Using a previously published multi-component joint computational model, we explored the impact of increasing degree of meniscectomy and osteochondral flow conductivity on joint lubrication. Results suggest a greater effect of meniscectomy on joint lubrication when the osteochondral junction is healthy. However, the impact is less pronounced when the osteochondral junction is already diseased due to compromised lubrication capability. This research provides a first-time quantitative analysis of this interaction, which highlights the importance of adequately evaluating the osteochondral junction's condition before meniscectomy surgery. It also suggests that reducing post-surgery activity level may be beneficial for patients with diseased junctions undergoing meniscectomy. [ABSTRACT FROM AUTHOR]

This review article aims to reinforce anatomical concepts about meniscal tears while linking associated treatment options. The main teaching points start with the basic meniscal anatomy and key differences between the medial and lateral menisci. Subsequently, various meniscal tear patterns along with their associated history and physical exam findings will be discussed with corresponding illustrations and MR images. Additional discussion will involve the different surgical repair techniques (with arthroscopic correlates), their indications with pertinent imaging findings, imaging related to previous meniscal tear repairs, and novel surgical techniques. Lastly, keys to evaluating for retear with an emphasis on MRI arthrogram findings will be reviewed. While each of these topics is not discussed in totality, the key points of the review article will enforce key concepts and help radiologists evaluate the menisci on imaging. • MRI is the imaging modality of choice for evaluation of suspected meniscal tears. • The meniscal tear patterns are radial, horizontal, vertical, oblique, and complex. • Surgical management options include partial meniscectomy and meniscal repair. • More novel techniques include meniscal transplantation and scaffolding. • Meniscal re-tears are best evaluated with MR arthrography. [ABSTRACT FROM AUTHOR]

Background: For the surgical treatment of severe partial articular surface tendon avulsion (PASTA) lesions, 2 repair techniques, i.e., arthroscopic trans-tendon repair and arthroscopic repair after conversion to a full thickness tear, are widely used, and a satisfactory clinical outcome with both has been reported. The purpose of this study was to investigate integrity of the repaired rotator cuff based on second-look arthroscopy and to compare the above two repair techniques.Methods: Thirty-seven shoulders underwent PASTA lesion repair arthroscopically, with 20 shoulders receiving second-look arthroscopy. According to the repair technique, the shoulders were divided into 2 groups, which were 10 shoulders with trans-tendon repair (group P) and 10 shoulders with repair after conversion to a full thickness tear (group C). Second-look arthroscopy was done at a minimum of 3 months after initial surgery, with the mean interval until second-look arthroscopy being 5.6 months (3-13) in group P and 5.1 months (3-9) in group C. The reasons for second-look arthroscopy were pain with contracture in 15 patients, as well as pain in 4 patients and muscle weakness at abduction in one patient.Results: In group P, there was complete rotator cuff continuity in 3 shoulders, partial continuity in 4, and failure in 3, while group C had complete continuity in 8 shoulders, partial continuity in 1, and failure in 1. Adhesions of the subacromial bursa were seen in all shoulders, while contracture of the posterior capsule was noted in 5 shoulders from group P and 9 shoulders from group C, and contracture of the rotator interval was identified in 7 shoulders from group P and 9 shoulders from group C.Conclusions: Second-look arthroscopy revealed that the integrity of the rotator cuff after trans-tendon repair of severe PASTA lesions was often unsatisfactory in patients with symptomatic shoulder. On the other hand, complete continuity was seen in most shoulders underwent repair after conversion to a full thickness tear. [ABSTRACT FROM AUTHOR]

Background: Arthroscopic partial meniscectomy may cause knee osteoarthritis, which may be related to altered joint loading. Previous research has failed to demonstrate that exercise can reduce medial compartment knee loads following meniscectomy but has not considered muscular loading in their estimates.Research Question: What is the effect of exercise compared to no intervention on peak medial tibiofemoral joint contact force during walking using an electromyogram-driven neuromusculoskeletal model, following medial arthroscopic partial meniscectomy?Methods: This is a secondary analysis of a randomized controlled trial (RCT). 41 participants aged between 30-50 years with medial arthroscopic partial meniscectomy within the past 3-12 months, were randomly allocated to either a 12-week, home-based, physiotherapist-guided exercise program or to no exercise (control group). Three-dimensional lower-body motion, ground reaction forces, and surface electromyograms from eight lower-limb muscles were acquired during self-selected normal- and fast-paced walking at baseline and follow-up. An electromyogram-driven neuromusculoskeletal model estimated medial compartment contact forces (body weight). Linear regression models evaluated between-group differences (mean difference (95% CI)).Results: There were no significant between-group differences in the change (follow-up minus baseline) in first peak medial contact force during self-selected normal- or fast-paced walking (0.07 (-0.08 to 0.23), P = 0.34 and 0.01 (-0.19 to 0.22), P = 0.89 respectively). No significant between-group difference was found for change in second peak medial contact force during normal- or fast-paced walking (0.09 (-0.09 to 0.28), P = 0.31 and 0.02 (-0.17 to 0.22), P = 0.81 respectively). At the individual level, variability was observed for changes in first (range -26.2% to +31.7%) and second (range -46.5% to +59.9%) peak tibiofemoral contact force.Significance: This is the first study to apply electromyogram-driven neuromusculoskeletal modelling to an exercise intervention in a RCT. While our results suggest that a 12-week exercise program does not alter peak medial knee loads after meniscectomy, within-participant variability suggests individual-specific muscle activation patterns that warrant further investigation. [ABSTRACT FROM AUTHOR]

Background: Partial meniscectomy dramatically increases the risk for post-traumatic, tibiofemoral osteoarthritis after anterior cruciate ligament reconstruction (ACLR). Concomitant medial meniscus surgery influences walking biomechanics (e.g., medial tibiofemoral joint loading) early after ACLR; whether medial meniscus surgery continues to influence walking biomechanics two years after ACLR is unknown.Research Question: Does medial meniscus treatment at the time of ACLR influence walking biomechanics two years after surgery?Methods: This is a secondary analysis of prospectively collected data from a clinical trial (NCT01773317). Fifty-six athletes (age 24 ± 8 years) with operative reports, two-year biomechanical analyses, and no second injury prior to two-year testing participated after primary ACLR. Participants were classified by concomitant medial meniscal status: no medial meniscus involvement (n = 36), partial medial meniscectomy (n = 9), and medial meniscus repair (n = 11). Participants underwent biomechanical analyses during over-ground walking including surface electromyography; a validated musculoskeletal model estimated medial compartment tibiofemoral contact forces. Gait variables were analyzed using 3 × 2 ANOVAs with group (medial meniscus treatment) and limb (involved versus uninvolved) comparisons.Results: There was a main effect of group (p = .039) for peak knee flexion angle (PKFA). Participants after partial medial meniscectomy walked with clinically meaningfully smaller PKFAs in both the involved and uninvolved limbs compared to the no medial meniscus involvement group (group mean difference [95%CI]; involved: -4.9°[-8.7°, -1.0°], p = .015; uninvolved: -3.9°[-7.6°, -0.3°], p = .035) and medial meniscus repair group (involved: -5.2°[-9.9°, -0.6°], p = .029; uninvolved: -4.7°[-9.0°, -0.3°], p = .038). The partial medial meniscectomy group walked with higher involved versus uninvolved limb medial tibiofemoral contact forces (0.45 body weights, 95% CI: -0.01, 0.91 BW, p = 0.053) and truncated sagittal plane knee excursions, which were not present in the other two groups.Significance: Aberrant gait biomechanics may concentrate high forces in the antero-medial tibiofemoral cartilage among patients two years after ACLR plus partial medial meniscectomy, perhaps explaining the higher osteoarthritis rates and offering an opportunity for targeted interventions.Level Of Evidence: Level III. [ABSTRACT FROM AUTHOR]

Study Objective: Arthroscopic knee procedures are increasingly being performed in an outpatient setting. Appropriate intraoperative anesthesia is vital to prevent complications such as unanticipated hospital admission. We examined differences in complications between general (GA) vs neuraxial anesthesia (NA) as the primary anesthetic for patients undergoing arthroscopic knee procedures.Design: This was a retrospective cohort study. We queried the National Surgical Quality Improvement Program for arthroscopic knee procedures performed between 2007 and 2016. We compared postoperative complication rates between propensity-matched cohorts (NA vs GA). The anesthesia groups were matched based on age, race, BMI, gender, diabetes, smoking history, COPD, CHF, functional status, HTN, ASA class, steroid use, bleeding disorder history, and readmission status. Univariable and multivariable logistic regression were used to compare factors associated with inpatient admission - defined as hospital length of stay >1 day.Patients: A total of 57,494 patients were included - 55,257 GA and 2237 NA patients.Main Results: Among the matched cohorts, NA patients were significantly more likely to be admitted to the hospital postoperatively (p < 0.001). Neuraxial anesthesia (OR 5.93, 95% CI 4.90-7.21) use was also significant in the final multivariable regression model for inpatient admission. Additional significant predictors for inpatient admission included history of bleeding disorder (OR 5.44, 95% CI 2.14-12.76), Asian race (OR 6.47, 95% CI 4.90-8.56), COPD (OR 3.10, 95% CI 1.94-4.82), diabetes (OR 1.90, 95% CI 1.43-2.49), and increased operation time (OR 3.01, 95% CI 2.69-3.37).Conclusions: NA was significantly associated with inpatient admission following knee arthroscopy. Further research should focus on examining the reason for this association and methods to reduce inpatient admission for patients undergoing arthroscopic knee procedures using neuraxial anesthesia. [ABSTRACT FROM AUTHOR]

A 54-year old woman with primary osteoarthritis and a tibial bone marrow lesion underwent subchondroplasty with injectable calcium phosphate. Post-operatively, the patient's symptoms worsened, and she lost the ability to bear weight. Follow-up MRI revealed previously absent, diffuse STIR hyperintensity in the tibia extending far beyond the surgical site. Twelve months post-operatively, symptoms spontaneously resolved. As the prevalence of subchondroplasty grows it will be important to recognize potential complications. To the authors' best knowledge this is the first report of significantly worsening pain and difficulty bearing weight corresponding with diffuse hyperintense T2 signal in the tibia after a calcium phosphate subchondroplasty. • Subchondroplasty is emerging as an alternative to knee replacement. • As the procedure gains popularity, it is important to recognize complications. • Follow-up magnetic resonance imaging showed increased intensity in the tibia. • First report of worsening pain with imaging changes after subchondroplasty. • Further study evaluating post-operative imaging and complications is needed. [ABSTRACT FROM AUTHOR]

Abstract Site-specific and depth-dependent properties of cartilage were implemented within a finite element (FE) model to determine if compositional or structural changes in the tissue could explain site-specific alterations of chondrocyte deformations due to cartilage loading in rabbit knee joints 3 days after a partial meniscectomy (PM). Depth-dependent proteoglycan (PG) content, collagen content and collagen orientation in the cartilage extracellular matrix (ECM), and PG content in the pericellular matrix (PCM) were assessed with microscopic and spectroscopic methods. Patellar, femoral groove and samples from both the lateral and medial compartments of the femoral condyle and tibial plateau were extracted from healthy controls and from the partial meniscectomy group. For both groups and each knee joint site, axisymmetric FE models with measured properties were generated. Experimental cartilage loading was applied in the simulations and chondrocyte volumes were compared to the experimental values. ECM and PCM PG loss occurred within the superficial cartilage layer in the PM group at all locations, except in the lateral tibial plateau. Collagen content and orientation were not significantly altered due to the PM. The FE simulations predicted similar chondrocyte volume changes and group differences as obtained experimentally. Loss of PCM fixed charge density (FCD) decreased cell volume loss, as observed in the medial femur and medial tibia, whereas loss of ECM FCD increased cell volume loss, as seen in the patella, femoral groove and lateral femur. The model outcome, cell volume change, was also sensitive to applied tissue geometry, collagen fibril orientation and loading conditions. [ABSTRACT FROM AUTHOR]

Anterior cruciate ligament (ACL) and meniscus injuries are highly correlated with post-traumatic knee osteoarthritis (PTOA). The aim of this study was to examine whether early intervention with low-intensity pulsed ultrasound (LIPUS) at an intensity of 0.1 W/cm2 helps delay PTOA progression. A PTOA model was established by ACL transection and meniscectomy in male Sprague-Dawley rats. LIPUS intervention (1.0 MHz, 0.1 W/cm2) started on the third day after surgery and continued for 4 consecutive wk. Histopathological analyses and immunoassays of collagen type II and matrix metallopeptidase 13 in joints were conducted. Results indicated that compared with the sham treatment, LIPUS significantly reduced Mankin scores, inflammatory cells and matrix metallopeptidase 13 expression and increased collagen type II expression in rats with PTOA (p < 0.05). Early intervention with LIPUS has beneficial effects on delaying cartilage degradation by reducing synovial inflammation and matrix metallopeptidase 13 expression, as well as enhancing collagen type II expression in cartilage. [ABSTRACT FROM AUTHOR]

Environmental disruption of the circadian rhythm is linked with increased pain due to osteoarthritis (OA). We aimed to characterize the role of the clock gene in OA-induced pain more systemically using both genetic and pharmacological approaches. Genetically modified mice, (bmal1f/fNav1.8CreERT mice), generated by deleting the critical clock gene, bmal1 , from Nav1.8 sensory neurons, were resistant to the development of mechanical hyperalgesia associated with OA induced by partial medial meniscectomy (PMM) of the knee. In wild-type mice, induction of OA by PMM surgery led to a substantial increase in BMAL1 expression in DRG neurons. Interestingly, pharmacological activation of the REV-ERB (a negative regulator of bmal1 transcription) with SR9009 resulted in reduction of BMAL1 expression, and a significant decrease in mechanical hyperalgesia associated with OA. Cartilage degeneration was also significantly reduced in mice treated with the REV-ERB agonist SR9009. Based on these data, we also assessed the effect of pharmacological activation of REV-ERB using a model of environmental circadian disruption with its associated mechanical hyperalgesia, and noted that SR9009 was an effective analgesic in this model as well. Our data clearly demonstrate that genetic disruption of the molecular clock, via deletion of bmal1 in the sensory neurons of the DRG, decreases pain in a model of OA. Furthermore, pharmacological activation of REV-ERB leading to suppression of BMAL1 expression may be an effective method for treating OA-related pain, as well as to reduce joint damage associated with this disease. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to analyze the association between the prevalence of meniscal and chondral lesions and the timing of surgery in patients undergoing primary anterior cruciate ligament (ACL) reconstruction to determine a safe time for surgery.Methods: This retrospective study involved 226 patients (91 females and 135 males; median age, 29 years) undergoing primary ACL reconstruction. Time interval from ACL injury to surgery (median, 4 months; range, 1-420 months) and concomitant meniscal and cartilage lesions in ACL reconstruction were reviewed. Receiver operating characteristic (ROC) curve analysis was used to determine the precise threshold interval to surgery to prevent meniscal or cartilage lesions. The risk of lesion occurrence after each cutoff period was determined using odds ratio (OR).Results: The incidences of medial meniscus (MM), lateral meniscus (LM), and cartilage lesions were 43.8%, 32.7%, and 27.4%, respectively. ROC analysis revealed that patients who waited for more than 6, 4, and 5 months for ACL reconstruction had a significantly greater risk of associated MM, LM, and chondral lesions, respectively. Patients who underwent ACL reconstruction ≥7 months after injury had OR of 4.1 (p < 0.001) for the presence of MM lesion as compared with those who underwent reconstruction within 6 months. Similarly, patients who underwent ACL reconstruction ≥5 months after injury had OR of 1.9 (p = 0.023) for the presence of LM lesion as compared with those who underwent reconstruction within 4 months, and patients who underwent ACL reconstruction ≥6 months after injury had OR of 2.9 (p < 0.001) for chondral lesion as compared with those who underwent reconstruction within 6 months.Conclusion: ACL reconstruction should be performed within approximately 6 months after the injury to prevent associated meniscal or chondral lesions. [ABSTRACT FROM AUTHOR]

We investigated the effects of isolated meniscectomy on tibiofemoral skeletal kinematics and cartilage contact arthrokinematics in vivo . We recruited nine patients who had undergone isolated medial or lateral meniscectomy, and used a dynamic stereo-radiography (DSX) system to image the patients’ knee motion during decline walking. A volumetric model-based tracking process determined 3D tibiofemoral kinematics from the recorded DSX images. Cartilage contact arthrokinematics was derived from the intersection between tibial and femoral cartilage models co-registered to the bones. The kinematics and arthrokinematics were analyzed for early stance and loading response phase (30% of a gait cycle), comparing the affected and intact knees. Results showed that four patients with medial meniscectomy had significantly greater contact centroid excursions in the meniscectomized medial compartments while five patients with lateral meniscectomy had significantly greater cartilage contact area and lateral shift of contact centroid path in the meniscectomized lateral compartments, comparing to those of the same compartments in the contralateral intact knees. No consistent difference however was identified in the skeletal kinematics. The current study demonstrated that cartilage-based intra-articular arthrokinematics is more sensitive and insightful than the skeletal kinematics in assessing the meniscectomy effects. [ABSTRACT FROM AUTHOR]

Tissue-engineered meniscus regeneration is a very promising treatment strategy for meniscus lesions. However, generating the scaffold presents a huge challenge for meniscus engineering as this has to meet particular biomechanical and biocompatibility requirements. In this study, we utilized acellular meniscus extracellular matrix (AMECM) and demineralized cancellous bone (DCB) to construct three different types of three-dimensional porous meniscus scaffold: AMECM, DCB, and AMECM/DCB, respectively. We tested the scaffolds' physicochemical characteristics and observed their interactions with meniscus fibrochondrocytes to evaluate their cytocompatibility. We implanted the three different types of scaffold into the medial knee menisci of New Zealand rabbits that had undergone total meniscectomy; negative control rabbits received no implants. The reconstructed menisci and corresponding femoral condyle and tibial plateau cartilage were all evaluated at 3 and 6 months (n = 8). The in vitro study demonstrated that the AMECM/DCB scaffold had the most suitable biomechanical properties, as this produced the greatest compressive and tensile strength scores. The AMECM/DCB and AMECM scaffolds facilitated fibrochondrocyte proliferation and the secretion of collagen and glycosaminoglycans (GAGs) more effectively than did the DCB scaffold. The in vivo experiments demonstrated that both the AMECM/DCB and DCB groups had generated neomeniscus at both 3 and 6 months post-implantation, but there was no obvious meniscus regeneration in the AMECM or control groups, so the neomeniscus analysis could not perform on AMECM and control group. At both 3 and 6 months, histological scores were better for regenerated menisci in the AMECM/DCB than in the DCB group, and significantly better for articular cartilage in the AMECM/DCB group compared with the other three groups. Knee MRI scores (Whole-Organ Magnetic Resonance Imaging Scores (WORMS)) were better in the AMECM/DCB group than in the other three groups at both 3 and 6 months. At both 3 and 6 months, RT-PCR demonstrated that aggrecan, Sox9, and collagen II content was significantly higher, and mechanical testing demonstrated greater tensile strength, in the AMECM/DCB group neomenisci compared with the DCB group. [ABSTRACT FROM AUTHOR]

We determined the biomechanical responses of chondrocytes to indentation at specific locations within the superficial zone of cartilage (i.e. patellar, femoral groove, femoral condylar and tibial plateau sites) taken from female New Zealand white rabbits three days after a partial meniscectomy in the lateral compartment of a knee joint. Confocal laser scanning microscopy combined with a custom indentation system was utilized to image chondrocyte responses at sites taken from ten contralateral and experimental knee joints. Cell volume, height, width and depth changes, global, local axial and transverse strains and Young׳s moduli were determined. Histological assessment was performed and proteoglycan content from the superficial zone of each site was determined. Relative to contralateral group cells, patellar, femoral groove and lateral femoral condyle cells in the experimental group underwent greater volume decreases ( p < 0.05), due to smaller lateral expansions (with greater decreases in cell height only for the lateral femoral condyle cells; p < 0.05) whereas medial femoral and medial tibial plateau cells underwent smaller volume decreases ( p < 0.05), due to less deformation in cell height ( p < 0.05). Proteoglycan content was reduced in the patellar ( p > 0.05), femoral groove, medial femoral condyle and medial tibial plateau experimental sites ( p < 0.05). The findings suggest: (i) cell biomechanical responses to cartilage loading in the rabbit knee joint can become altered as early as 3 days after a partial meniscectomy, (ii) are site-specific, and (iii) occur before alterations in tissue mechanics or changes detectable with histology. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effects of arthroscopic irrigation on cartilage superficial zone lubricin and surface friction. Arthroscopic partial meniscectomy is one of the most commonly performed orthopedic surgeries in the United States, but rates of osteoarthritis progression following this procedure are high. The effect of arthroscopic irrigation on articular surface lubrication has not been previously considered as a contributing factor in outcomes after arthroscopy. Fourteen bovine stifle joints were randomized to receive arthroscopic irrigation ( n =7) or no treatment ( n =7). Full-thickness osteochondral explants from these joints underwent friction testing to measure static and dynamic coefficients of friction. Following mechanical testing, samples were fixed and stained for lubricin. Percent integrated density, a measure of the amount of lubricin in the superficial zone (0–100 µm depth), was determined. Static and dynamic coefficients of friction were found to be significantly greater in arthroscopy specimens compared to controls ( p =0.02 and p <0.001, respectively). Percent integrated density of lubricin in the superficial zone was significantly lower in arthroscopy specimens compared to controls ( p <0.001). [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is a degenerative disease associated with joint inflammation, articular cartilage degeneration and subchondral hypertrophy. Small molecules which both ameliorate chondrocyte OA phenotype and activate bone marrow-derived mesenchymal stem cells (BMSCs) chondrogenesis under inflammatory conditions have the therapeutical potential for OA treatment. In this study, we characterized a novel small molecule which could ameliorate OA progression via novel regulating mechanisms. Docosahexaenoic acid (DHA), a bioactive molecule, was screened from a small molecule library and showed anti-inflammatory and chondroprotective effects in OA chondrocytes, as well as ameliorated IL-1β impaired BMSCs chondrogenesis in Wnt/β-catenin and NF-κB signaling dependent manners. Furthermore, Malat1 was found to be the key mediator of DHA-mediating anti-inflammation chondroprotection and chondrogenesis. DHA also rescued cartilage loss and damage in a surgery-induced OA mice model. The elevation of serum Malat1 levels caused by OA was also downregulated by DHA treatment. Taken together, our findings demonstrated that DHA, with a dual-signaling repression property, exerted its anti-inflammation, chondroprotection and chondrogenesis function possibly via regulating Malat1 level, suggesting that it may be a possible drug candidate for OA patients with elevated MALAT1 expression levels. [Display omitted] [ABSTRACT FROM AUTHOR]

• When the meniscus width dropped progressively in the range of 8-12 mm, the peak stress in the knee joint increased slowly. • The biomechanical environment of the knee joint is significantly deteriorated when the lateral meniscus is retained insufficiently (width <8 mm). • The peak stress position shifted from medial to lateral when the width of the residual lateral meniscus was reduced. • Impingement of the medial femoral intercondylar cartilage with the medial tibial eminence was observed when the meniscus width was reduced to 2 mm. Incidence of osteoarthritis and genu valgus is higher after partial meniscectomy of the discoid lateral meniscus. We aimed to provide a biomechanical reference for slowing the development of osteoarthritis and genu valgus after complete discoid lateral meniscus (CDLM) surgery. Computed tomography and magnetic resonance images of the knee were used to establish a finite element model of the knee. The discoid lateral meniscus model was cut at 2-mm intervals to obtain 10 lateral meniscus models of different widths (2–20 mm). The instantaneous stress peak and knee valgus angle were obtained by finite element analysis under the same coaxial load. When the residual width of the lateral meniscus was greater than 12 mm, the peak stress of the knee joint and angle of genu valgus did not significantly change from preoperative levels. The contact stress peak increased slightly as the width decreased from 12 to 8 mm. When the width was reduced from 8 to 0 mm, the contact stress peak increased significantly. For partial meniscectomy in CDLM patients, meniscus width of 8–10 mm provides a better biomechanical environment. This may reduce risk of early knee degeneration and valgus from excessive meniscectomy in conventional surgery. [ABSTRACT FROM AUTHOR]

Adult spinal deformity (ASD) patients maintain upright posture by compensating through their spine, pelvis and lower extremities. Little data exist quantifying the contribution of lower extremity compensation through the hips, knees, and ankles to maintain upright posture. Evaluate the effect of the lower limb compensation by numerically unfolding patients. Multicenter, prospective cohort. A total of 288 patients surgically treated for complex ASD with preoperative full body images. Horizontal distance between vertebra centroid and ankle. Surgical ASD patients were enrolled into a prospective study based on three criteria deformity severity (PI-LL>25°, TPA>30°, SVA>15cm, TCobb>70° or TLCobb>50°), procedure complexity (>12 levels fused, 3CO or ACR) and/or age (>65 and >7 levels fused). Preop full-body images were evaluated and age and PI-adjusted normative values were used to model spine alignment based upon three configurations: COMP (all lower extremity compensatory mechanisms maintained), PARTIAL (removal of ankle dorsiflexion and knee flexion, maintained hip extension), UNCOMP (ankle, knee, and hip compensation eliminated by reset PT to the age and PI norms). The three configurations were compared, and COMP alignment was stratified by TPA percentiles to investigate the offsets from each vertebra to the ankle joint acting as a surrogate of the gravity line in free-standing position. A total of 288 patients met inclusion criteria (60±15yo, 70.5% female, 27.4±5.9 BMI). COMP spine deformity magnitude included PI-LL 15±24, TPA 24±14, and SVA 65±69mm. As the model transitioned from COMP to UNCOMP alignment, the initial posterior translation of the pelvis decreased significantly to an anterior translation vs the ankle (P.Shift 30 to -7.6 mm). This was associated with a decrease in pelvic retroversion (PT 24.1 to 16.1), hip extension (SFA 203 to 200), knee flexion (KA 5.5 to -0.4), and ankle dorsiflexion (AA 5.3 to 3.7). As a result, the anterior malalignment of the trunk significantly increased SVA (65 to 120mm) and G-SVA (C7-Ankle from 36 to 127 mm), leading to a three-fold increase in bending moments sustained by the ankle joint. The stratification of the COMP position by TPA percentiles revealed that as the deformity increases, the vertebrae above T8 translate anteriorly, those below T10 move posteriorly, with the T8-T10 segment remaining ∼3cm posterior to the ankle joint independently of the deformity severity. Removal of lower limbs' compensation revealed an unsustainable truncal malalignment with a three-fold increase of bending moments at the ankle joints. Combined, lower limb compensations permit "reducing" the SVA by two-fold and the C7-ankle SVA by three-fold. From a mechanical point of view, this compensation permits maintaining the trunk center of mass (T9) at a fixed offset of ∼3 cm from the ankle joint. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background Knee osteoarthritis is common in people who have undergone partial meniscectomy, and a higher external knee flexion moment during gait may be a potential contributor. Although the peak external knee flexion moment has been shown to increase from 3 months to 2 years following partial meniscectomy, mechanisms underpinning the increase in the peak knee flexion moment are unknown. Methods Sixty-six participants with partial meniscectomy completed three-dimensional gait (normal and fast pace) and quadriceps strength assessment at baseline (3 months following partial meniscectomy) and again 2 years later. Variables included external knee flexion moment, vertical ground reaction force, knee flexion kinematics, and quadriceps peak torque. Findings For normal pace walking, the main significant predictors of change in peak knee flexion moment were an increase in peak vertical ground reaction force (R 2 = 0.55), mostly due to an increase in walking speed, and increase in peak knee flexion angle (R 2 = 0.19). For fast pace walking, the main significant predictors of change in peak knee flexion moment were an in increase in peak vertical ground reaction force (R 2 = 0.51) and increase in knee flexion angle at initial contact (R 2 = 0.17). Change in peak vertical force was mostly due to an increase in walking speed. Interpretation Findings suggest that increases in vertical ground reaction force and peak knee flexion angle during stance are predominant contributors to the 2-year change in peak knee flexion moment. Future studies are necessary to refine our understanding of joint loading and its determinants following meniscectomy. [ABSTRACT FROM AUTHOR]

Purpose This study was performed to quantitatively evaluate postoperative changes in cartilage by T2 mapping after arthroscopic partial medial meniscectomy. Material and Methods The study enrolled 17 patients with 20 knees that underwent arthroscopic partial medial meniscectomy. MRI was performed preoperatively and at six months postoperatively, with subjects evaluated by T 2 mapping of the central part of the medial condyle of the femur in the sagittal plane. Regions of interest (ROIs) were set at 10 points between the point of intersection of the anatomical axis of the femur and the articular surface of the medial condyle and posterior area approximately 90 degrees to the anatomical axis. Pre- and postoperative T 2 values at each ROI were evaluated. Results Postoperative T 2 values were significantly longer than preoperative values at approximately 20, 30, 40, and 50 degrees to the anatomical axis of the femur. The maximum change between pre- and postoperative T 2 values was + 6.65% at 30 degrees to the anatomical axis. Conclusions Mechanical stress at positions approximately 20, 30, 40, and 50 degrees relative to the anatomical axis of the femur increased soon after arthroscopic medial meniscectomy. These findings indicate the start of degeneration, via disorganization of collagen arrays, of the articular cartilage and increased water content. [ABSTRACT FROM AUTHOR]

Background Few studies have examined whether chondral lesions encountered in patients undergoing meniscectomy should be surgically treated. The primary aim of the ChAMP (Chondral Lesions And Meniscus Procedures) Trial is to determine whether there is a difference in knee pain between patients undergoing debridement versus observation of chondral lesions encountered during arthroscopic meniscectomy. This paper describes the rationale and study design for the ChAMP Trial. Methods/Design The ChAMP Trial is a randomized controlled trial of patients aged 30 and older undergoing partial meniscectomy and randomly allocated to debridement (CL-Deb, N = 98) or observation (CL-Obs, N = 92) of chondral lesions identified during surgery and deemed to be significant (Outerbridge Grade II-IV). Patients and data collectors were unaware of treatment allocation until completion of the study. Patients with surgically insignificant (Outerbridge Grade I) chondral lesions or no chondral lesions were included as a third non-randomized comparison group (NoCL, N = 76). The primary outcome is the difference in knee pain assessed by WOMAC (Western Ontario and McMaster Universities Arthritis Index) between the CL-Deb and CL-Obs groups at 1-year after surgery. Secondary outcomes include 1-year differences in additional measures of knee pain, function, symptoms, activity, and quality of life assessed by the WOMAC, KOOS (Knee Injury and Osteoarthritis Outcome Score), visual analog pain scale, and physical exam; as well as general health assessed with the SF-36 (Short-form Health Survey). Increased intraoperative costs associated with the addition of chondral debridement will also be assessed. Discussion This study will add to the scant literature regarding management of chondral lesions in patients undergoing meniscectomy and might provide treatment guidance for clinicians and their patients. [ABSTRACT FROM AUTHOR]

Since meniscal geometry affects the cartilage contact pressures, it is essential to carefully define the geometry of the synthetic meniscal implant that we developed. Recently, six independent modes of sizeand shape-related geometry variation were identified through 3D statistical shape modeling (SSM) of the medial meniscus. However, this model did not provide information on the functional importance of these geometry characteristics. Therefore, in this study finite element simulations were performed to determine the influence of anatomically-based meniscal implant size and shape variations on knee cartilage contact pressures. Finite element simulations of the knee joint were performed for a total medial meniscectomy, an allograft, the average implant geometry, six implant sizes and ten shape variations. The geometries of the allograft and all implant variations were based on the meniscus SSM. Cartilage contact pressures and implant tensile strains were evaluated in full extension under 1200 N of axial compression. The average implant induced cartilage peak pressures intermediate between the allograft and meniscectomy and also reduced the cartilage area subjected to pressures >5 MPa compared to the meniscectomy. The smaller implant sizes resulted in lower cartilage peak pressures and compressive strains than the allograft, yet high implant tensile strains were observed. Shape modes 2, 3 and 6 affected the cartilage contact stresses but to a lesser extent than the size variations. Shape modes 4 and 5 did not result in changes of the cartilage stress levels. The present study indicates that cartilage contact mechanics are more sensitive to implant size than to implant shape. Down-sizing the implant resulted in more favorable contact mechanics, but caused excessive material strains. Further evaluations are necessary to balance cartilage contact pressures and material strains to ensure cartilage protection and longevity of the implant. [ABSTRACT FROM AUTHOR]

Mechanical signals experienced by chondrocytes (articular cartilage cells) modulate cell synthesis and cartilage health. Multi-scale modeling can be used to study how forces are transferred from joint surfaces through tissues to chondrocytes. Therefore, estimation of chondrocyte behavior during certain physical activities, such as walking, could provide information about how cells respond to normal and abnormal loading in joints. In this study, a 3D multi-scale model was developed for evaluating chondrocyte and surrounding peri- and extracellular matrix responses during gait loading within healthy and medial meniscectomy knee joints. The knee joint geometry was based on MRI, whereas the input used for gait loading was obtained from the literature. Femoral and tibial cartilages were modeled as fibril-reinforced poroviscoelastic materials, whereas menisci were considered as transversely isotropic. Fluid pressures in the chondrocyte and cartilage tissue increased up to 2 MPa (an increase of 30%) in the meniscectomy joint compared to the normal, healthy joint. The elevated level of fluid pressure was observed during the entire stance phase of gait. A medial meniscectomy caused substantially larger (up to 60%) changes in maximum principal strains in the chondrocyte compared to those in the peri- or extracellular matrices. Chondrocyte volume or morphology did not change substantially due to a medial meniscectomy. Current findings suggest that during walking chondrocyte deformations are not substantially altered due to a medial meniscectomy, while abnormal joint loading exposes chondrocytes to elevated levels of fluid pressure and maximum principal strains (compared to strains in the peri- or extracellular matrices). These might contribute to cell viability and the onset of osteoarthritis. [ABSTRACT FROM AUTHOR]

Meniscal tears are common injuries, and while partial meniscectomy is a frequent treatment option, general meniscus loss is a risk factor for the development of osteoarthritis. The goal of this study was to measure the in vivo tibiofemoral cartilage contact patterns in patients with meniscus tears in relation to biomarkers of cartilage catabolism in the synovial fluid of these joints. A combination of magnetic resonance imaging and biplanar fluoroscopy was used to determine the in vivo motion and cartilage contact mechanics of the knee. Subjects with isolated medial meniscus tears were analyzed while performing a quasi-static lunge, and the contralateral uninjured knee was used as a control. Synovial fluid was collected from the injured knee and matrix metalloproteinase (MMP) activity, sulfated glycosaminoglycan, cartilage oligomeric matrix protein, prostaglandin E2, and the collagen type II cleavage biomarker C2C were measured. Contact strain in the medial compartment increased significantly in the injured knees compared to contralateral control knees. In the lateral compartment, the contact strain in the injured knee was significantly increased only at the maximum flexion angle (105°). The average cartilage strain at maximum flexion positively correlated with total MMP activity in the synovial fluid. These findings show that meniscal injury leads to loss of normal joint function and increased strain of the articular cartilage, which correlated to elevated total MMP activity in the synovial fluid. The increased strain and total MMP activity may reflect, or potentially contribute to, the early development of osteoarthritis that is observed following meniscal injury. [ABSTRACT FROM AUTHOR]

This study investigated the effect of mechanical anchoring on the development of fiber organization and anisotropy in anatomically shaped tissue engineered menisci. Bovine meniscal fibrochondrocytes were mixed with collagen and injected into molds designed to produce meniscus implants with 12 mm extensions at each horn. After a day of static culture, 10 and 20 mg/ml collagen menisci were either clamped or unclamped and cultured for up to 8 weeks. Clamped menisci were anchored in culture trays throughout culture to mimic the native meniscus horn attachment sites, restrict contraction circumferentially, and encourage circumferential alignment. Clamped menisci retained their size and shape, and by 8 weeks developed circumferential and radial fiber organization that resembled native meniscus. Clamping also increased collagen accumulation and improved mechanical properties compared to unclamped menisci. Enhanced organization in clamped menisci was further reflected in the development of anisotropic tensile properties, with 2-3 fold higher circumferential moduli compared to radial moduli, a similar ratio to native meniscus. Ten and 20 mg/ml clamped menisci had similar levels of organization, with 20 mg/ml menisci producing larger diameter fibers and significantly better mechanical properties. Collectively, these data demonstrate the benefit of using bio-inspired mechanical boundary conditions to drive the formation of a highly organized collagen fiber network. [ABSTRACT FROM AUTHOR]

Meniscal damage and meniscectomy lead to subsequent osteoarthritis (OA) of the knee joint through multiple and diverse mechanisms, yet the interaction of these mechanisms remains unknown. Therefore, the aim of this review is to suggest the multi-scale, multi-faceted components involved between meniscal injury or meniscectomy and the initiation of OA. There is evidence of structural, mechanical, and biological changes after meniscal damage, all of which can be greatly affected by the presence of local or systemic inflammation. Meniscal damage or resection causes changes in knee mechanics during walking, resulting in altered cartilage loading. Because cartilage is mechanically sensitive, these loading changes can initiate a catabolic effect, culminating in tissue degeneration. The evidence suggests that the addition of elevated inflammation at the time of meniscal damage or meniscectomy results in an accelerated progression toward cartilage degradation. Initial cartilage degradation produces inflammation and pain in conjunction with structural changes to the joint, thus perpetuating the cycle of altered cartilage loading and subsequent degradation. Furthermore, the inflammation secondary to obesity and aging introduces an increased risk of developing OA following meniscal injury. Therefore, an overall route between meniscal damage or resection and OA is presented here in a manner that considers two distinct pathways; these pathways reflect the absence or presence of conditions that cause elevated inflammation. [ABSTRACT FROM AUTHOR]

Meniscal properties for computational methods have already been proposed. However, it is well known that there is high intra subject variability in the material properties of soft tissues and that disruption of the fiber network alters the biomechanics of the meniscus. Therefore, the objective of this study was to establish a non invasive method to determine the material properties of the individual menisci and their attachments using inverse FE-analyses. In a previous study, the 3D displacements of the meniscus and its attachments under axial joint loads were determined for intact porcine knees. To simulate the experimental response in individual FEanalyses (n=5), an anisotropic, hyperelastic meniscus matrix was embedded in a poroelastic model. During a particle swarm optimization, the difference between the force applied to the meniscus during the experiment and the femoral surface reaction force of the FE model at equilibrium was minimized by varying four material parameters. Afterwards, a prediction error was determined to describe how well the material parameter fit to each of the three displacement directions. Additionally, the stresses occurring in the meniscus were evaluated. The error of the material parameter optimization was on average 6.5±4.4%. The best fitting material parameter combination revealed an error of 1.2%. The highest stresses occurred in the region between the pars intermedia and posterior horn of the meniscus. The individual material properties of the meniscus were successfully obtained with a combination of previously reported, noninvasively measured 3D displacements and inverse FE-analyses. The methodology presented in this study is a promising contribution to the detection of degeneration within the meniscus. [ABSTRACT FROM AUTHOR]

Background: Current evidence suggests limiting arthroscopic meniscectomy to those patients with no or early arthritis however outcomes of arthroscopic meniscectomy with patients of a higher body mass index (BMI) are not as widely available. The aim of this study was to determine if patient reported outcome scores for arthroscopic meniscectomy are adversely affected by the degree of knee osteoarthritis or patient BMI. Methods: All patients who underwent arthroscopic meniscectomy within the NHS in Scotland between the 6th of February and 29th of April 2012 were audited as part of the Scottish Government Musculoskeletal Audit and were eligible for inclusion within this study. A total of 270 patients returned both their pre-operative and post-operative EuroQol 5Q5D5L descriptive questionnaire and Knee injury and Osteoarthritis Outcomes Scores. Patients were stratified according to BMI, degree of osteoarthritis, history of injury, and duration of knee symptoms. Results: Pre-operative to post-operative EuroQol index scores [0.642 ± 0.253 to 0.735 ± 0.277, median ± SD] and Knee injury and Osteoarthritis Outcome Scores [44.63 ± 18.78 to 62.28 ± 24.94, median ± SD] improved across all patients (p < 0.0001). This was irrespective of degree of BMI, history of injury, or duration of symptoms. There was no such improvement in patients with moderate to severe osteoarthritis. Those patients with a BMI > 35 kg/m² had lower post-operative scores than the pre-operative scores of those of BMI <30 kg/m². Conclusions: Arthroscopic meniscectomy is beneficial regardless of patient BMI, duration of symptoms, history of injury, or in the presence of early osteoarthritis. [ABSTRACT FROM AUTHOR]

The article describes the case of a 6-year-old girl who suffered from severe valgus knee deformity resulting from chondronecrosis after using a radiofrequency (RF) device. Her knees gave out while running and magnetic resonance imaging (MRI) showed a complete lateral discoid meniscus. The article discusses clinical long-term results of lateral discoid meniscectomy in children and the concern about thermal damage to cartilage caused by RF devices.

Tissue engineering is a promising field of study toward curing the meniscal deficient stifle; however the ideal cell type for this task is not known. We describe here the extraction of synoviocytes and meniscal fibrochondrocytes from arthroscopic debris from six dogs, which were cultured as tensioned bioscaffolds to synthesize meniscal-like fibrocartilage sheets. Despite the diseased status of the original tissues, synoviocytes and meniscal fibrochondrocytes had high viability at the time of removal from the joint. Glycosaminoglycan and collagen content of bioscaffolds did not differ. Meniscal fibrochondrocyte bioscaffolds contained more type II collagen, but collagen deposition was disorganized, with only 30-40% of cells viable. The collagen of synoviocyte bioscaffolds was organized into sheets and bands and 80-90% of cells were viable. Autologous, diseased meniscal fibrochondrocytes and synoviocytes are plausible cell sources for future meniscal tissue engineering research, however cell viability of meniscal fibrochondrocytes in the tensioned bioscaffolds was low. [ABSTRACT FROM AUTHOR]

People following arthroscopic partial medial meniscectomy (APM) are at increased risk of developing knee osteoarthritis. High impact loading and peak loading early in the stance phase of gait may play a role in the pathogenesis of knee osteoarthritis. This was a secondary analysis of longitudinal data to investigate loading-related indices at baseline in an APM group (3 months post-surgery) and a healthy control group, and again 2 years later (follow-up). At baseline, 82 participants with medial APM and 38 healthy controls were assessed, with 66 and 23 re-assessed at follow-up, respectively. Outcome measures included: (i) heel strike transient (HST) presence and magnitude, (ii) maximum loading rate, (iii) peak vertical force (Fz) during early stance. At baseline, maximum loading rate was lower in the operated leg (APM) and non-operated leg (non-APM leg) compared to controls (p⩽0.03) and peak Fz was lower in the APM leg compared to non-APM leg (p⩽0.01). Over 2 years, peak Fz increased in the APM leg compared to the non-APM leg and controls (p⩽0.01). Following recent APM, people may adapt their gait to protect the operated knee from excessive loads, as evidenced by a lower maximum loading rate in the APM leg compared to controls, and a reduced peak Fz in the APM leg compared to the non-APM leg. No differences at follow-up may suggest an eventual return to more typical gait. However, the increase in peak Fz in the APM leg may be of concern for long-term joint health given the compromised function of the meniscus. [ABSTRACT FROM AUTHOR]

Background Knee osteoarthritis is common following arthroscopic partial meniscectomy and a higher external peak knee adduction moment is believed to be a contributor. The peak knee adduction moment has been shown to increase over 2 years (from 3-months post-arthroscopic partial meniscectomy). The aim of this study was to evaluate mechanisms underpinning the increase in peak knee adduction moment over 2 years observed in people 3-months following arthroscopic partial meniscectomy. Methods Sixty-six participants with medial arthroscopic partial meniscectomy were assessed at baseline and again 2 years later. Parameters were evaluated at time of peak knee adduction moment as participants walked barefoot at their self-selected normal and fast pace for both time points. Findings For normal pace walking, an increase in frontal plane ground reaction force-to-knee lever arm accounted for 30% of the increase in peak knee adduction moment (B = 0.806 [95% CI 0.501–1.110], P < 0.001). For fast pace walking, an increase in the frontal plane ground reaction force magnitude accounted for 21% of the increase in peak knee adduction moment (B = 2.343 [95% CI 1.219–3.468], P < 0.001); with an increase in tibia varus angle accounting for a further 15% (B = 0.310 [95% CI 0.145–0.474], P < 0.001). Interpretation Our data suggest that an increase in lever arm and increase in frontal plane ground reaction force magnitude are contributors to the increased knee adduction moment observed over time in people following arthroscopic partial meniscectomy. [ABSTRACT FROM AUTHOR]

Abstract: The menisci fulfill key biomechanical functions in the tibiofemoral (knee) joint. Unfortunately meniscal injuries are quite common and most often treated by (partial) meniscectomy. However, some patients experience enduring symptoms, and, more importantly, it leads to an increased risk for symptomatic osteoarthritis. Over the past decades, researchers have put effort in developing a meniscal substitute able to prevent osteoarthritis and treat enduring clinical symptoms. Grossly, two categories of substitutes are observed: First, a resorbable scaffold mimicking biomechanical function which slowly degrades while tissue regeneration and organization is promoted. Second, a non resorbable, permanent implant which mimics the biomechanical function of the native meniscus. Numerous biomaterials with different (material) properties have been used in order to provide such a substitute. Nevertheless, a clinically applicable cartilage protecting material is not yet emerged. In the current review we provide an overview, and discuss, these different materials and extract recommendations regarding material properties for future developmental research. [Copyright &y& Elsevier]

Background: Postoperative knee joint chondrolysis is a rare but serious complication. The aim of our study is to report the clinical presentation, the early, mid and long-term outcomes of rapid chondrolysis after a partial lateral meniscectomy in elite athletes. Methods: Clinical records of 10 consecutive cases of rapid chondrolysis after partial lateral meniscectomy in eight professional athletes were retrospectively reviewed. There were seven males and one female with a mean age of 25.2 years (range 20-32 years) at index procedure. An initial conservative approach to its treatment was attempted in all cases. Arthroscopic lavage was advocated in two cases. Patients were clinically reviewed at last follow-up with comparative X-rays, a subjective IKDC, a Lysholm and Tegner scale. Results: All patients resumed their pre-injury level of activity at a mean 8 (±2.45) months after the index procedure. At a mean of 82(± 36) months of follow-up, the mean subjective IKDC, Lyshom and Tegner scale were respectively 82.64 (±8.61), 86.6 (±6.44), 9 (±1.41). All knees demonstrated joint space narrowing scored Kellgren and Lawrence II (n = 1) III (n = 4) or IV (n = 5) on conventional radiographs. Conclusion: By reviewing the common factors in each of these cases we believe that rapid chondrolysis occurs primarily due to the excessive loading of the articular cartilage in the lateral compartment of the knee. In this series, although the results in the medium term were good, the long-term outcome must be guarded due to the high rate of radiographic osteoarthritis of the lateral compartment seen in this population. Study design: Retrospective case series, Level IV. [ABSTRACT FROM AUTHOR]