The arcuate ligament revisited: role of the posterolateral structures in providing static stability in the knee joint.

PURPOSE: To determine the involvement of the posterolateral structures including the lateral collateral ligament, the popliteus muscle-tendon unit, the arcuate ligament (popliteofibular ligament, fabellofibular ligament, popliteomeniscal fascicles, capsular arm of short head of the biceps femoris and anterolateral ligament) and the posterior cruciate ligament in providing restraint to excessive recurvatum, tibial posterior translation and external tibial rotation at 90° of flexion. METHODS: Ten fresh-frozen cadaveric knees were tested with dial test, posterior drawer test and recurvatum test. The values were collected, using a surgical navigation system, on intact knees, following a serial section of the posterolateral corner (lateral collateral ligament, arcuate ligament and popliteus muscle-tendon unit), followed by the additional section of the posterior cruciate ligament. RESULTS: The mean tibial external rotation, recurvatum and posterior drawer were, respectively, measured at 9° ± 4°, 2° ± 3° and 9 ± 1 mm on intact knees. These values increase to 12° ± 5°, 3° ± 2° and 9 ± 1 mm after cutting the lateral collateral ligament; 17° ± 6° (p < 0.05), 3° ± 2° and 10 ± 1 mm after sectioning the arcuate ligament; 18° ± 7°, 3° ± 2° and 10 ± 1 mm after sectioning the popliteus muscle-tendon unit and 27° ± 6° (p < 0.05), 5° ± 3° (p < 0.05) and 28 ± 2 mm (p < 0.05) after the additional section of the posterior cruciate ligament. CONCLUSION: Among the different structures of the posterolateral corner, only the arcuate ligament has a significant role in restricting excessive primary and coupled external rotation. The popliteus muscle-tendon unit is not a primary static stabilizer to tibial external rotation at 90° of knee flexion. The posterior cruciate ligament is the primary restraint to excessive recurvatum and posterior tibial translation. The posterior cruciate ligament and the arcuate ligament have predominant role for the posterolateral stability of the knee. The functional restoration of these ligaments is an important part of the surgical treatment of posterolateral ligamentous injuries.

Efficiency of locking-plate fixation in isolated talonavicular fusion.

INTRODUCTION: Talonavicular (TN) fusion is an effective means of treating hindfoot deformity and pain. At the cost of a certain limited morbidity, it allows lasting stabilization of all of the torque joints. Non-union rates, however, are high, due to insufficient mechanical stability of the fixation. The present study assessed radiological and clinical results in TN fusion fixed by two retrograde compression screws and a dorsal locking plate. MATERIAL AND METHOD: A retrospective single-surgeon study recruited 26 TN fusions performed in 25 patients (13 male, 12 female; mean age, 54.6±15.4years) between March 1st, 2010 and February 28th, 2014. Mean follow-up was 14.9±8.7months. Bone fusion and anatomic results were assessed on dorsoplantar, lateral and Méary weight-bearing radiographs. RESULTS: Radiologic fusion was achieved in all cases, at a mean 2.7±0.7months. Mean TN coverage angle was 21.7±10.5° preoperatively and 3.8±1.8° at follow-up. Mean AOFAS score improved significantly, from 37.2±11.8 (range, 20-53) preoperatively to 79.4±11.4 (range, 45-98) at follow-up. CONCLUSION: TN fusion fixed by two retrograde compression screws and a dorsal locking plate provided a high rate of consolidation without loss of angular correction and with satisfactory clinical results. LEVEL OF EVIDENCE: IV. TYPE OF STUDY: Retrospective.

Prevalence of knee stiffness after arthroscopic bone suture fixation of tibial spine avulsion fractures in adults.

BACKGROUND: Tibial spine avulsion fractures (TSAFs) occur chiefly in adolescents. Few published data are available on outcomes after arthroscopic surgical treatment of TSAFs in adults. OBJECTIVES: To evaluate outcomes of consecutive patients with TSAFs managed by arthroscopic bone suture followed by a standardised non-aggressive rehabilitation programme. HYPOTHESIS: Arthroscopic bone suture followed by non-aggressive rehabilitation therapy reliably produces satisfactory outcomes in adults with TSAF. METHODS: Thirteen adults were included. Outcomes were evaluated based on the Tegner score, International Knee Documentation Committee (IKDC) score, anterior-posterior knee laxity, passive and active motion ranges, and radiological appearance. RESULTS: After a mean follow-up of 41±27months (12-94months), all 13 patients had healed fractures without secondary displacement. No patient had knee instability. Post-operative stiffness was noted in 5 patients (2 with complex regional pain syndrome and 3 with extension lag), 1 of whom required surgical release. The mean IKDC score was 91.3±11.7. The mean Tegner score was 5.46±1.37 compared to 6.38±0.70 before surgery. Mean tibial translation (measured using the Rolimeter) was 1.09±1.22mm, compared to 5.9±1.85mm before surgery. CONCLUSION: The outcomes reported here support the reliability of arthroscopic bone suture for TSAF fixation. Nevertheless, a substantial proportion of patients experienced post-operative stiffness, whose contributory factors may include stunning of the quadriceps due to the short time from injury to surgery and the use of a gentle rehabilitation programme. LEVEL OF EVIDENCE: IV, retrospective study of treatment outcomes.

Dual mobility cup in revision total hip arthroplasty: dislocation rate and survival after 5 years.

BACKGROUND: Dislocation is a common complication of total hip arthroplasty (THA), particularly when performed as revision surgery. Dual mobility cups (DMCs) minimize the risk of instability when implanted during primary THA. However, their usefulness and survival in revision THA remain unclear. We therefore conducted a retrospective study to assess DMC stability and survival at a minimal follow-up period of 5years after revision THA. HYPOTHESIS: The dislocation rate associated with DMCs for revision THA is similar to that seen after primary THA. MATERIALS AND METHODS: Cup exchange with implantation of a DMC was performed in 71 patients (74 hips) between 2000 and 2007, for the following reasons: recurrent dislocation (n=22), aseptic loosening (n=38), and infection (n=14). The DMCs were cemented in 47 cases and cementless in 27 cases. The clinical variables (Merle d'Aubigné-Postel score and Harris Hip Score) and radiological findings were collected retrospectively from the medical records and compared with those obtained at the last follow-up visit. RESULTS: Of the 74 cases, 2 were lost to follow-up. At last follow-up, the mean Merle d'Aubigné-Postel score was 15.2 (11-18) and the mean Harris Hip Score was 80.4 (51-98). Of the 8 failures, 2 (2/72, 2.7%) were related to mechanical factors (1 case each of aseptic loosening and dislocation) and 6 were changed because of infection (recurrent infection, n=4). Mechanical failure was not linked to a specific reason for revision THA. A radiolucent line was visible in 4 cases but this finding was not associated with clinical manifestations. When failure was defined as cup revision for any non-infectious complication, 5-year implant survival was 99% (95% confidence interval, 93-100%). DISCUSSION: Use of a DMC in revision THA was associated with a slightly higher dislocation rate (1/72, 1.4%) than in primary THA, whereas 5-year survival was comparable. Cemented DMCs were not associated with a greater risk of loosening. CONCLUSION: DMCs are useful to decrease the risk of dislocation in revision THA performed for any reason. The low rate of loosening indicates that DMCs do not result in high stresses at the bone-implant interface. LEVEL OF EVIDENCE: IV, retrospective study.

Rapid chondrolysis following an unoperated lateral meniscus tear in a young professional rugby player.

Rapid chondrolysis following a lateral meniscectomy is a rare complication. We present the first reported case of rapid chondrolysis of the lateral compartment, which developed 6 months after a meniscus tear that was not surgically treated in a young 18-year-old professional rugby player. The possible hypotheses to explain this complication are presented, and certain previously published causes were excluded (iatrogenic during surgery, undiagnosed increased rotatory instability, chondrotoxicity of bupivacaine). Overloading of the cartilage surface of the lateral compartment from meniscal extrusion can cause cartilage necrosis.

Endoscopic repair of partial-thickness undersurface tears of the gluteus medius tendon.

UNLABELLED: Partial-thickness tear of the gluteus medius and minimus muscles has recently been recognized as a cause of chronic trochanteric pain resistant to medical treatment. The present article reports an original endoscopic technique of identification and repair. It uses a standard arthroscope at 30°, with the patient in lateral decubitus, without fluoroscopy. In case of partial-thickness undersurface tear, careful hook palpation followed by bursa exploration enables the pathological tendon to be diagnosed. A trans-tendinous approach then allows debridement, with systematic resection of the bone structures implicated in the impingement, followed by side-to-side tendon suture. LEVEL OF EVIDENCE: Level IV (case series).

Medial unicompartmental knee arthroplasty: does tibial component position influence clinical outcomes and arthroplasty survival?

INTRODUCTION: In several recent studies, unicompartmental knee arthroplasty (UKA) produced better functional outcomes than did total knee arthroplasty with 10-year prosthesis survival rates greater than 95%. Nevertheless, UKA is still widely viewed as producing inconsistent results. Tibial component loosening is the leading cause of failure. We consequently sought to identify tibial component position criteria associated with outcomes of medial UKA. MATERIAL AND METHODS: We conducted a retrospective multicentre study of 559 medial UKAs performed between 1988 and 2010 in 421 patients (262 females and 159 males) with a mean age of 69.51±8.72 years at surgery. We recorded the following radiographic parameters: joint space height, obliquity and slope of the tibial implant, whether the tibial component was perpendicular to the femoral component, and lower limb malalignment. The International Knee Society (IKS) score was used to assess clinical outcomes. Mean follow-up at re-evaluation was 5.17±4.33 years. RESULTS: The mean 10-year prosthesis survival rate was 83.7±3.5%. Factors associated with decreased prosthesis survival were a greater than 2-mm change in joint space height, a greater than 3° change in tibial component obliquity, a slope value greater than 5° or a change in slope greater than 2°, and more than 6° of divergence between the tibial and femoral components. Residual mechanical varus of 5° or more was also associated with mechanical failure. The only factor associated with worse functional score values was joint space elevation by more than 2mm. DISCUSSION: The high level of accuracy required for optimal positioning of the tibial component during medial UKA indicates a need for considerable technical expertise and emphasises the conservative nature of the procedure. Optimal positioning is crucial to restore normal knee kinematics and to prevent implant wear and lesions to adjacent compartments. LEVEL OF EVIDENCE: IV, retrospective study.