Search

Lateral ligament ankle sprains are common and the anatomy on imaging studies is vital for accurate diagnosis. The lateral fibulotalocalcaneal ligament (LFTCL) complex consists of the inferior fascicle of the anterior talofibular ligament (ATFL) which is connected by arciform fibres with the calcaneofibular ligament (CFL). The superior fascicle of ATFL is an independent structure that should be assessed individually. MRI evaluation of these distinct fascicles and the arciform fibres has not been described. The aim of this study is to identify the anatomical relationship of these components of the LFTCL complex in healthy individuals on MRI.Thirty ankles from healthy volunteers were imaged using 3D volumetric MRI. The ATFL fascicles and size were evaluated. Presence of arciform fibres connecting the inferior ATFL fascicle and CFL to form the LFTCL complex and anatomical relationship around the lateral ligament complex were assessed.Both the superior and inferior ATFL fascicles were observed in 26 (86.7%) ankles. The superior ATFL fascicle was significantly larger in all specimens (39% longer and 80.7% wider). For the specimens with a single fascicle, this was similar in size to the superior fascicle observed in the other 26 specimens. These measurements were not affected by age or gender. Arciform fibres of the LFTCL complex were identified in 22 (84.6%) specimens with two ATFL fascicles and three (75%) ankles with a single ATFL fascicle. Connecting fibres from the ATFL to PTFL were observed in 19 (63.3%) ankles while connections between the CFL and PTFL were identified in 21 (70%) ankles. Five ankles had a perforating artery visualized in the intervening space between the superior and inferior ATFL fascicles (a branch of the lateral tarsal artery of the dorsalis pedis artery).Two distinct ATFL fascicles may be identified in the majority of ankles on MRI. Isolated injury to the superior fascicle identified on MRI may be useful when diagnosing patients presenting with symptoms of subtle instability without overt ankle laxity on clinical examination. The current study is the first to identify the arciform fibres of the LFTCL complex supporting isolated ATFL repair in the presence of intact LFTCL complex.Level III.

Background The treatment of meniscus injuries combined with anterior cruciate ligament (ACL) reconstruction would be important to improve outcomes after ACL reconstruction. However, the effects of treatment methods for meniscus after ACL reconstruction have not been thoroughly investigated. The objective of this study was to investigate the effects of treatment methods for meniscus on clinical and radiological outcomes at 2 years after ACL reconstruction. Methods Three-hundred and eighteen patients with primary ACL reconstruction using autologous hamstring tendon registered in our multicenter study database and who were followed up for 2 years were included. They were then divided into 3 groups, the no meniscal lesion/untreated group (n = 149), the meniscal repair group (n = 139), and the meniscal resection group (n = 30). Patient-based subjective evaluations (Lysholm score, Knee injury and Osteoarthritis Outcome score and International Knee Documentation Committee subjective score), objective evaluations (Lachman test, pivot shift test and KT measurement), and radiological measurements (medial and lateral joint space width) were compared among the 3 groups preoperatively and at 2 years follow-up. Results All subjective scores and objective evaluations significantly improved in all groups without significant differences among the groups postoperatively. Regarding radiological findings, the medial joint space width significantly decreased only in the resection group during the 2-year period, and the medial joint space width in the resection group was significantly smaller than that of the other groups at the 2-year follow-up. Moreover, the medial joint space width significantly decreased during the 2-year period when MM was resected. Conclusions In radiological findings, medial meniscus resection decreased medial joint space width two years after ACL reconstruction. On the other hand, treatment methods for meniscus neither significantly affected subjective nor objective findings until the 2-year follow-up. Level of evidence Ⅱ, Cohort study.

BACKGROUND Arthroscopic debridement is a common surgical treatment for patients with anterolateral impingement (ALI) of the ankle. Although they often have a history of ankle sprain, information regarding the role of ankle instability in ALI is limited. The aims of this review were to 1) assess the clinical outcomes of arthroscopic surgical treatment for ALI of the ankle and 2) review the data regarding anterior talofibular ligament (ATFL) injury and lateral ankle instability in patients who underwent arthroscopic surgery for ALI. METHOD A literature search of Pubmed and EMBASE was performed. Studies that met the following inclusion criteria were reviewed: (1) human clinical studies investigating patients who underwent arthroscopic surgery for ALI; (2) results with at least one scoring system with minimum follow-up of six months. The quality of each study was evaluated using the Oxford CEBM tool to assess the level of evidence and the grade of recommendation. The data of patient characteristics, intra-operative findings and clinical outcomes were extracted. RESULTS Eight articles were included in this systematic review, all of which were graded level 4 with grade C recommendation. In total, 203 patients with a mean age of 32 years (ranging from 11 to 74) were analysed. AOFAS score was used in 6 studies and scored 90.1 on average at follow-up. Two other studies used original scores. One study reported arthroscopic findings of the ATFL and another study reported on residual instability after surgery. New ankle sprains during follow-up period were reported in 8.3 to 20.0% of patients in 4 studies. DISCUSSION This review showed good clinical results of arthroscopic debridement with a grade C recommendation. Reports regarding arthroscopic observation of the ATFL and residual instability after surgery were lacking. Further investigation of what we are still calling "ALI" should be made with higher level of evidence focusing more on ATFL injury and its effect on clinical outcomes.

A human hand is a complex biomechanical system, in which bones, ligaments, and musculotendon units dynamically interact to produce seemingly simple motions. A new physiological hand simulator has been developed, in which electromechanical actuators apply load to the tendons of extrinsic hand and wrist muscles to recreate movements in cadaveric specimens in a biofidelic way. This novel simulator simultaneously and independently controls the movements of the wrist (flexion/extension and radio-ulnar deviation) and flexion/extension of the fingers and thumb. Control of these four degrees of freedom (DOF) is made possible by actuating eleven extrinsic muscles of the hand. The coupled dynamics of the wrist, fingers, and thumb, and the over-actuated nature of the human musculoskeletal system make feedback control of hand movements challenging. Two control algorithms were developed and tested. The optimal controller relies on an optimization algorithm to calculate the required tendon tensions using the collective error in all DOFs, and the action-based controller loads the tendons solely based on their actions on the controlled DOFs (e.g., activating all flexors if a f lexing moment is required). Both controllers resulted in hand movements with small errors from the reference trajectories (< 3.4◦); however, the optimal controller achieved this with 16% lower total force. Owing to its simpler structure, the actionbased controller was extended to enable feedback control of grip force. This simulator has been shown to be a highly repeatable tool (< 0.25 N and < 0.2◦ variations in force and kinematics, respectively) for in vitro analyses of human hand biomechanics.

Background:The biomechanical function of the anterolateral structure (ALS), which includes the anterolateral joint capsule and anterolateral ligament (ALL), remains a topic of debate.Hypothesis:The ALS contributes to knee joint stability during the Lachman test and the pivot-shift test in anterior cruciate ligament (ACL)–deficient knees.Study Design:Controlled laboratory study.Methods:Fourteen fresh-frozen hemipelvis lower limbs were used. For 7 specimens, the anterior one-third of the ALS and the residual ALS were cut intra-articularly with a radiofrequency device. Subsequently, the ACL was cut arthroscopically. For the other 7 specimens, the ACL was cut first, followed by the anterior one-third of the ALS and the residual ALS intra-articularly. During the procedures, the iliotibial band (ITB) was kept intact. At each condition, the anterior tibial translation (ATT) during the manual Lachman test and the acceleration of posterior tibial translation (APT) and the posterior tibial translation (PTT) during the manual pivot-shift test were measured quantitatively with an electromagnetic measurement system. The mean values of those parameters were compared among 6 groups (ACL intact, one-third ALS cut, all ALS cut, ACL cut, ACL/one-third ALS cut, and ACL/all ALS cut).Results:The mean ATTs during the Lachman test and the mean APTs and PTTs in the ACL-cut conditions (ACL cut, ACL/one-third ALS cut, and ACL/all ALS cut) were significantly larger than those under the ACL-intact conditions (ACL intact, one-third ALS cut, all ALS cut) ( P < .01). However, no statistically significant differences were observed among the intact, one-third ALS–cut, and all ALS–cut conditions, within the ACL-intact or ACL-cut conditions.Conclusion:Intra-articular dissection of the ALS did not increase the ATT during the Lachman test or the APT and PTT during the pivot-shift test under the intact condition of the ITB, regardless of the integrity of the ACL. When the ITB is intact, the ALS does not have a significant role in either anterior or dynamic rotatory knee stability, while the ACL does.Clinical Relevance:Recent growing interest about ALL reconstruction or ALS augmentation may not have a large role in controlling either anterior or dynamic rotatory knee instability in isolated ACL-deficient knees.

Background: Recently reported anterolateral structure reconstructions (ALSRs) to augment intra-articular anterior cruciate ligament reconstruction (ACLR) use various femoral attachment sites, and their biomechanical effects are still unknown. Hypothesis: ALSR concomitant with ACLR would control anterolateral rotational instability better than ACLR alone, and if ALSR had different femoral attachment sites, there would be different effects on its control of anterolateral rotational instability. Study Design: Controlled laboratory study. Methods: Twelve fresh-frozen hemipelvis lower limbs were included. Anterior tibial translation during the Lachman test and tibial acceleration during the pivot-shift test were measured with a 3-dimensional electromagnetic measurement system in situations with the (1) ACL and ALS intact, (2) ACL and ALS cut, (3) ALSR without ACLR (ALSR alone), (4) ACLR without ALSR (ACLR alone), and (5) ALSR with ACLR. Three femoral attachment sites were used for ALSR: F1, 2 mm anterior and 2 mm distal to the lateral epicondyle; F2, 4 mm posterior and 8 mm proximal to the lateral epicondyle; and F3, over-the-top position for the lateral extra-articular tenodesis. The Steel test and Wilcoxon signed rank test were used for statistical analysis. Results: Anterior tibial translation during the Lachman test in the ACL and ALS–cut state was significantly larger than it was in the ACL and ALS–intact state, while its difference disappeared after ACLR. As for the pivot-shift test, additional ALSR with F2 to ACLR significantly decreased the acceleration ( P = .046), although additional ALSR with F1 and F3 showed no significant effect. Conclusion: ALSR with the femoral attachment site 4 mm posterior and 8 mm proximal to the lateral epicondyle in addition to ACLR played a role in reducing anterolateral rotational instability the most effectively among the measured attachment sites. Clinical Relevance: The present data will contribute to determine the appropriate femoral attachment site for ALSR to better control anterolateral rotational instability after ACL reconstruction.

Purpose: Subcutaneous patient-controlled analgesia (PCA) has been widely used for orthopedic surgeries including total knee arthroplasty (TKA). This study aims to clarify the usefulness of subcutaneous PCA in the early phase after TKA. Methods: Our subjects consisted of 88 osteoarthritis knee patients who underwent primary TKA, and were classified into two groups: 42 patients received a subcutaneous PCA (containing fentanyl and droleptan) after operation (PCA group), and 46 patients were managed without a subcutaneous PCA (control group). We compared the incidence of side effects for 3 days postoperatively, measuring the number of times patients used adjuvant analgesia and range of motion on day 7 between the two groups. 34 of 42 patients in the PCA group tolerated PCA use until POD 3 (continuation sub-group), while 8 patients could not continue PCA (interruption sub-group). Demographic data of the two sub-groups were compared. Results: The mean number of times adjunctive analgesics were used by the PCA group (3.7 ± 2.2) was significantly less than in the control group (5.4 ± 2.8) (p = 0.0049). There were no significant differences in the frequency of side effects between the two groups. There was no significant difference in range of motion between the two groups. Comparing the continuation and interruption sub-groups, patients over 80 years old were at risk to discontinue a subcutaneous PCA (p = 0.0319, odds ratio 5.4). Conclusion: These findings demonstrate that subcutaneous PCA would be a safe postoperative pain regimen for TKA patients, but the effect was not enough to promote early functional recovery. Levels of evidence: Therapeutic, Level Ⅱ. Keywords: Subcutaneous patient controlled analgesia (PCA), Total knee arthroplasty (TKA). postoperative pain control

Background Inversion ankle sprains, or lateral ankle sprains, often result in symptomatic lateral ankle instability, and some patients need lateral ankle ligament reconstruction to reduce pain, improve function, and prevent subsequent injuries. Although anatomically reconstructed ligaments should behave in a biomechanically normal manner, previous studies have not measured the strain patterns of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) after anatomical reconstruction. This study aimed to measure the strain patterns of normal and reconstructed ATFL and CFLs using the miniaturization ligament performance probe (MLPP) system. Methods The MLPP was sutured into the ligamentous bands of the ATFLs and CTLs of three freshly frozen cadaveric lower-extremity specimens. Each ankle was manually moved from 15° dorsiflexion to 30° plantar flexion, and a 1.2-N m force was applied to the ankle and subtalar joint complex. Results The normal and reconstructed ATFLs exhibited maximal strain (100) during supination in three-dimensional motion. Although the normal ATFLs were not strained during pronation, the reconstructed ATFLs demonstrated relative strain values of 16–36. During the axial motion, the normal ATFLs started to gradually tense at 0° plantar flexion, with the strain increasing as the plantar flexion angle increased, to a maximal value (100) at 30° plantar flexion; the reconstructed ATFLs showed similar strain patterns. Further, the normal CFLs exhibited maximal strain (100) during plantar flexion-abduction and relative strain values of 30–52 during dorsiflexion in three-dimensional motion. The reconstructed CFLs exhibited the most strain during dorsiflexion-adduction and demonstrated relative strain values of 29–62 during plantar flexion-abduction. During the axial motion, the normal CFLs started to gradually tense at 20° plantar flexion and 5° dorsiflexion. Conclusion Our results showed that the strain patterns of reconstructed ATFLs and CFLs are not similar to those of normal ATFLs and CFLs.

Background Measuring the strain patterns of ligaments at various joint positions informs our understanding of their function. However, few studies have examined the biomechanical properties of ankle ligaments; further, the tensile properties of each ligament, during motion, have not been described. This limitation exists because current biomechanical sensors are too big to insert within the ankle. The present study aimed to validate a novel miniaturized ligament performance probe (MLPP) system for measuring the strain patterns of the anterior talofibular ligament (ATFL) during ankle motion. Methods Six fresh-frozen, through-the-knee, lower extremity, cadaveric specimens were used to conduct this study. An MLPP system, comprising a commercially available strain gauge (force probe), amplifier unit, display unit, and logger, was sutured into the midsubstance of the ATFL fibers. To measure tensile forces, a round, metal disk (a “clock”, 150 mm in diameter) was affixed to the plantar aspect of each foot. With a 1.2-Nm load applied to the ankle and subtalar joint complex, the ankle was manually moved from 15° dorsiflexion to 30° plantar flexion. The clock was rotated in 30° increments to measure the ATFL strain detected at each endpoint by the miniature force probe. Individual strain data were aligned with the neutral (0) position value; the maximum value was 100. Results Throughout the motion required to shift from 15° dorsiflexion to 30° plantar flexion, the ATFL tensed near 20° (plantar flexion), and the strain increased as the plantar flexion angle increased. The ATFL was maximally tensioned at the 2 and 3 o’clock (inversion) positions (96.0 ± 5.8 and 96.3 ± 5.7) and declined sharply towards the 7 o’clock position (12.4 ± 16.8). Within the elastic range of the ATFL (the range within which it can return to its original shape and length), the tensile force was proportional to the strain, in all specimens. Conclusion The MLPP system is capable of measuring ATFL strain patterns; thus, this system may be used to effectively determine the relationship between limb position and ATFL ankle ligament strain patterns.

Background There are few reports in terms of detailed biomechanics of the deltoid ligament, and no reports have measured the biomechanics of each ligamentous band, due to the difficulty in inserting sensors into the narrow ligaments. This study aims to measure the strain pattern of the deltoid ligament bands using a miniaturization ligament performance probe (MLPP) system. Methods The MLPP was sutured into the ligamentous bands of the deltoid ligament in 6 fresh-frozen lower extremity cadaveric specimens. The strain was measured using a round metal disk (clock) fixed on the plantar aspect of the foot. The ankle was manually moved from 15° of dorsiflexion to 30° plantar flexion, and a 1.2-N-m force was applied to the ankle and subtalar joint complex. The clock was then rotated every 30° to measure the strain of each ligamentous band at each endpoint. Results The tibionavicular ligament (TNL) begins to tense at 10° plantar flexion and the tension becomes stronger as the angle increases; the TNL works most effectively in plantar flex-abduction. The tibiospring ligament (TSL) begins to tense gradually at 15° plantar flexion and the tension becomes stronger as the angle increases. The TSL works most effectively in the abduction. The tibiocalcaneal ligament (TCL) begins to tense gradually at 0° dorsiflexion, and the tension becomes stronger as the angle increases. The TCL works most effectively in pronation (dorsiflexion-abduction). The superficial posterior tibiotalar ligament (SPTTL) begins to tense gradually at 0° dorsiflexion, and the tension becomes stronger as the angle increases, with the SPTTL working most effectively in dorsiflexion. Conclusion Our results provide a better understanding of the biomechanical function of the superficial deltoid ligament and could help in improving repair and reconstruction procedures.

Objectives To compare the effects of anterior cruciate ligament (ACL) injuries and the preoperative period on functional status in different sports using preoperative patient data from the Multicenter Arthroscopic Knee Surgery (MAKS) study, a multicentre prospective cohort study of patients who underwent ACL reconstructions and meniscal surgeries conducted in 2013. Methods Of the 1648 patients registered in the MAKS study cohort, 826 underwent unilateral primary ACL reconstruction. These patients were divided into three groups based on sports activity type: contact, fighting and non-contact. The patients were further divided into two subgroups according to preoperative period data: acute (≤3 months) and chronic (>3 months). We standardised the preoperative evaluation items (Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) subjective form, and Lysholm score) and surgical records. Results The mean Lysholm score in the non-contact group was statistically significantly better than that in the fighting group. The two KOOS subcategories were statistically significantly superior in the non-contact group than in the fighting group. In the contact group, acute cases showed statistically significantly lower IKDC subjective scores and lower scores in two KOOS subcategories than the chronic cases. In the fighting group, chronic cases showed better IKDC subjective scores and scores for three KOOS subcategories than the acute cases. In the non-contact group, chronic cases showed better IKDC subjective scores and scores for all KOOS subcategories than the acute cases. Conclusion When athletes with ACL injuries are divided by sport type into fighting, contact and non-contact groups, the functional status of fighting sport athletes was more negatively influenced by ACL injury than those of non-contact sport athletes. When divided into acute and chronic phases, overall acute cases showed lower scores than the chronic cases in all sport types. In acute cases, the functional status of fighting sport athletes was more negatively influenced than non-contact sport athletes, whereas in chronic cases, there were no differences among the different sport types. The sport types and postinjury period should be considered for decision-making on therapeutic measures of patients with ACL injuries. Level of evidence Level II.

Purpose Discoid meniscus often causes mechanical problems and needs surgical treatment at an early age. However, many aspects of its morphological development and changes remain unknown. The purpose of this study was to investigate the insertion of the femoral anterior cruciate ligament (ACL) via the behind-ACL approach and the morphology of the lateral femoral condyle to which the ACL attaches to clarify the morphological characteristics of the knee with discoid lateral meniscus (DLM). Method Sixty-six patients with meniscus injury who underwent arthroscopic surgery were retrospectively reviewed. Preoperative plane radiographs were reviewed. To evaluate the shape of the femoral condyle, the ratio of the medial and lateral condyles, obliquity of the inter-epicondylar line, and the prominence ratio were assessed. From the arthroscopic observation using the behind-ACL approach, the insertion of the femoral ACL was classified as low, middle, and high based on the height from the deepest area of the articular surface to the direct insertion, including fibrous extension from the joint surface at 90° flexion. Results Twenty-nine patients had DLM (DLM group), and 37 patients had a semilunar meniscal injury (non-DLM group). The ratio of the lateral femoral condyle, obliquity of the inter-epicondylar line, and prominence ratio in the DLM group were significantly smaller than those in the non-DLM group. On the other hand, no significant difference in the ratio of the medial femoral condyle was observed. Arthroscopic evaluation revealed that the femoral ACL was significantly inserted lower in the DLM group than in the non-DLM group. Conclusion The femoral ACL with DLM was inserted close to the femoral joint surface with morphological abnormality in the knees with DLM related to hypoplasic of the lateral femoral condyle.

Exact knowledge of risk factors for residual anterolateral rotatinoal instability (ALRI) after anterior cruciate ligament (ACL) reconstruction is limited. The purpose of this study was to analyse possible risk factors for ALRI after ACL reconstruction.Quantitative assessment of the pivot shift phenomenon by measuring tibial acceleration was performed in 46 patients during primary double-bundle ACL reconstructions. The absolute value of the acceleration of the injured knee after provisional fixation of the ACL grafts ('absolute residual acceleration') and the subtraction of the acceleration of the uninjured knee from absolute residual acceleration ('relative residual acceleration') were defined as indicators for residual ALRI. The associations between these indicators and nine candidate risk factors were analysed using univariate and multiple regression analyses.Multiple regression analysis revealed that absolute residual acceleration was positively associated with both preoperative acceleration difference between injured and uninjured knees (β = 0.469, P 0.001) and tibial acceleration of the uninjured knee (β = 0.597, P 0.001). Relative residual acceleration was also positively associated with preoperative acceleration difference between injured and uninjured knees (β = 0.446, P 0.001), but was negatively associated with tibial acceleration of the uninjured knee (β = -0.763, P 0.001).Patients with larger preoperative side-to-side difference of the pivot shift phenomenon have higher risk for both absolute and relative residual ALRIs after ACL reconstruction, whereas patients with larger pivot shift phenomenon in their uninjured knees are at higher risk for absolute residual ALRI but not for relative residual ALRI.

Surgical treatment is sometimes required to treat the chronic lateral instability of the ankle to prevent the development of articular cartilage damage [1–3] and to prevent performance deterioration especially in toe-off phase. Recently, arthroscopic repair/reconstruction surgery for lateral instability of the ankle has been rapidly developing.

Bilateral chronic Achilles tendon rupture is a rare condition which is commonly associated with a predisposing factor such as long-term steroid therapy. Treatment of such patients requires special consideration since tendon fibers are usually weak due to steroid therapy and tendon ends are retracted. However, no consensus is available regarding the optimal surgical procedure. Ambulation after surgery is another problem; according to the literature, patients usually wore casts bilaterally and were kept non-weight bearing for several weeks after surgery, which means patients were usually not able to walk for several weeks after surgery. We present the case of bilateral chronic Achilles tendon ruptures in a patient on steroid therapy, which provided achievement of a good functional outcome with 1-year follow up through Achilles tendon reconstruction and early functional rehabilitation. This rehabilitation included starting to walk the day after surgery using patellar tendon bearing braces with wedges.

Several kinds of anterolateral ligament (ALL) reconstructions to augment intra-articular anterior cruciate ligament reconstruction to better control anterolateral rotational instability (ALRI) have been reported. However, the optimal femoral attachment site for ALL reconstruction is still unclear. The purpose of this study was to investigate the effects of different femoral attachment sites on the tension changes through knee motions in different situations in order to determine a recommended femoral attachment site for ALL reconstruction. Six fresh-frozen cadaveric knees were included. ALL reconstructions were performed with three different femoral attachment sites (F1: 2 mm anterior and 2 mm distal to the lateral epicondyle, F2: 4 mm posterior and 8 mm proximal to the lateral epicondyle and F3: position for the lateral extra-articular tenodesis). The graft tension changes were measured by a graft tensioning system during knee flexion–extension and manual maximum internal/external tibial rotation in the following situations: (1) intact, (2) ALL cut, (3) ALL and ACL cut and (4) ALL cut and ACL reconstructed. Effects of the different femoral attachment sites, the route superficial or deep to the LCL, and the situations of (1) to (4) were calculated via repeated-measures analysis of variance. The tension of F1 was higher in flexion and lower in extension, whereas the tension of F2 and F3 was higher in extension and lower in flexion. F2 showed the smallest tension change. Situations of (1) to (4) did not affect tension changes. The graft tension became higher with internal rotation and lower with external rotation regardless of femoral attachment sites or situations. With F2—4 mm posterior and 8 mm proximal to the lateral epicondyle—the reconstructed ALL had the least tension change with only a slight increase in tension as the knee extended. This result indicates that F2 is recommended for ALL reconstruction to better control ALRI, which will help determine the optimal femoral tunnel position for ALL reconstruction.

Background: Some types of meniscus tear, especially lateral meniscus tear, have been reported to be associated with rotatory knee laxity. However, precise information regarding the effect of meniscus repair on rotatory laxity is limited. The purpose of this study was to investigate the effects of lateral and medial meniscus repair on rotatory laxity in anterior cruciate ligament (ACL) injured knees. Methods: Forty-one patients who underwent ACL reconstruction were included in the study. The tibial acceleration during the pivot shift test was measured using a triaxial accelerometer preoperatively under anesthesia and intraoperatively before and after medial and lateral meniscus repair and ACL reconstruction during surgery. Effects of meniscus tear and its repair on rotatory laxity were analyzed. Results: Preoperative measurements revealed that patients with lateral meniscus tear showed significantly higher tibial acceleration compared to the patients without meniscus tear (P = 0.006). Intraoperative measurements revealed that medial and lateral meniscus repair significantly reduced tibial acceleration by 1.46 m/s2 (P = 0.002) and 1.91 m/s2 (P < 0.001), respectively. Conclusion: In ACL injured knees, knees with lateral meniscus tear showed greater rotatory laxity compared to the knees without meniscus tear. In addition, lateral meniscus repair, and to a lesser degree medial meniscus repair, reduced rotatory laxity during ACL reconstruction surgery. Therefore, the meniscus should be repaired as much as possible for its role as a secondary stabilizer of rotatory laxity. Besides, the effect of meniscus repair on rotatory laxity should be considered when the indication of anterolateral augmentation is determined.

To investigate the risk factors for residual pivot shift test after anterior cruciate ligament (ACL) reconstruction based on a multicenter prospective cohort study. This study included patients who were registered in the Multicenter Arthroscopic Knee Surgery Study, a prospective longitudinal multicenter cohort study, and who underwent primary ACL reconstruction using autologous hamstring tendon graft between 2013 and 2016. The exclusion criteria included prior injuries or surgeries in the contralateral knee, prior ligamentous injuries in the involved knee, grade 2 or 3 concomitant ligament injuries, and inflammatory or other forms of osteoarthritis. Data from the preoperative period and at 1-year follow-up were used for further analysis, and patients with incomplete data, re-injury and loss to follow-up were also excluded. Logistic regression analysis was conducted with age, gender, Lachman test, pivot shift test, KT measurement, hyperextension, single-bundle vs. double-bundle, meniscus injury sites, and meniscus treatments as the independent variables, and postoperative pivot shift test was used as the dependent variable. Three hundred and sixty-eight patients were included in the study. Hyperextension knee (P = 0.025) and a preoperative pivot shift test under anesthesia (P = 0.040) were identified as risk factors for a postoperative pivot shift via logistic regression analysis. There were no statistically significant differences in the other variables. The results from a multicenter cohort study indicated that knee hyperextension and greater preoperative pivot shift under anesthesia were risk factors for residual pivot shift at 1 year after ACL reconstruction. In cases with a preoperative high-grade pivot shift and knee hyperextension, additional anterolateral structure augmentation might be considered in order to eliminate pivot shift and eventually obtain better outcomes after ACL reconstruction. II.

The meniscus roots are critical for meniscus function in preserving correct knee kinematics and avoiding meniscus extrusion and, consequently, in the progression of osteoarthritis. Several techniques exist for medial meniscus posterior root tear repair; however, current surgical techniques have been proved to fail to reduce meniscus extrusion, which has been shown to be associated with development of osteoarthritis, although significant improvements in the postoperative clinical findings have been achieved. This Technical Note describes an arthroscopic technique for the medial meniscus posterior root tear in which a pullout repair is augmented by a centralization technique to restore and maintain the medial meniscus function by efficiently reducing meniscus extrusion.

The purposes of this study were to investigate (1) meniscus status and clinical findings in anterior cruciate ligament (ACL)-injured patients to clarify associations between the meniscus posterior root tear (PRT) and knee instability, and (2) magnetic resonance imaging (MRI) findings of the PRT to clarify sensitivity and specificity of MRI and prevalence of meniscus extrusion. Three hundred and seventeen patients with primary ACL reconstruction were included. PRTs for both medial and lateral sides were confirmed by reviewing surgical records. Preoperative MRI was reviewed to evaluate sensitivity and specificity of the PRT and meniscus extrusion width (MEW). Clinical information regarding the number of giving-way episodes, preoperative KT-1000 measurements and preoperative pivot shift was also assessed. Thirty-nine patients had a lateral meniscus (LM) PRT, whereas only four patients had a medial meniscus PRT. One hundred and seventeen patients had no meniscus tear (control). Twenty-eight patients (71.8%) showed positive signs of the LMPRT based on at least one view of MR images, with the coronal view showing the highest sensitivity. MEW in the LMPRT group was significantly larger than that in the control group. The preoperative pivot shift test grade in the LMPRT group was significantly greater than that in the control group. There were no significant differences in other parameters. In ACL-injured patients, the LMPRT was associated with ALRI as well as with meniscus extrusion. The coronal view of MRI was useful in identifying the LMPRT, although its sensitivity was not high. Therefore, surgeons should prepare to repair PRTs at the time of ACL reconstruction regardless of MRI findings, and they should make every effort to repair the LMPRT. III.

Background: Fatigue is thought to impact performance and may be a factor in injury mechanism. However, the full impact of a potentially fatiguing task on performance is unclear. Objective: To explore changes in maximum voluntary torque and electromyographic (EMG) activity following a sixty second isometric maximum voluntary contraction (MVC) of the quadriceps muscles and to follow the time course of any changes observed. Method: 21 subjects (14 males and 7 females) were recruited. Torque during brief maximum voluntary isometric contractions of the quadriceps muscle group was recorded in right and left legs using a Cybex Norm Isokinetic Dynamometer before, during and at intervals after a 60 second isometric fatigue task. EMG activity of the vastus medialis, rectus femoris and vastus lat eralis was also recorded synchronously. Results: Mean peak torque was significantly ( p < 0.05) lower in both legs at the end of the fatigue task. However, 10 minutes following the cessation of the task, it had increased and was significantly higher than the pre-fatigue level. It remaine d higher until the end of the protocol (30 mins post fatigue). The EMG amplitudes decreased slightly compared to pre-fatigue values during the fatigue task, a few of which were significantly low er than those of the pre-fatigue task. Following the fatigue task, EMG amplitudes increased gradually and were significantly h igher than those of the pre-fatigue task in all the muscles at the final time point. Median frequencies decreased significantly dur ing the fatigue task and were similar to pre-fatigue values by 5mins post-fatigue. Conclusion: This study has revealed that both torque and EMG rise following a sustained isometric 60 second hold to higher levels than pre-hold and that this rise is maintained for up t o 30 minutes. This rise however, was not associated with increased muscle firing frequency. The mechanisms behind this rise rem ain to be elucidated.