Lateral meniscal cysts: long-term clinical and radiological results of a partial meniscectomy and percutaneous decompressive needling.

INTRODUCTION: The aim of this study was to describe clinical and radiological long-term results of an arthroscopic partial meniscectomy associated with an outside-in decompressive needling of the cyst for lateral parameniscal cyst. METHODS: Eighteen patients with symptomatic parameniscal cysts treated between April 2002 and September 2009 were retrospectively included in the study. All patients underwent arthroscopic partial meniscectomy (preserving peripheral rim) and needling of the cyst using a 20-gauge needle. Pre- and post-operative IKDC, Tegner, and Lysholm scores were used to evaluate clinical results. Radiological results were obtained from pre- and post-operative radiographies and post-operative MRI scans. Both supine and weight bearing MRI examinations were performed. Kellgren-Lawrence and WORMS scales were used to evaluate osteoarthritis development of the knee. RESULTS: The mean follow-up period was 11.6 ± 2.6 years (range 7-15). Horizontal lesions were found in 56% of patients. All patients fully recovered. Mean Lysholm scores passed from mean pre-operative value 52 ± 16.9 to post-operative 85 ± 11.9 (P < 0.01) and mean IKDC scale score changed from 49.5 ± 14.7 to 67 ± 23.5 (P < 0.01). Mean Tegner scores did not change significantly. Post-operative radiographies showed a Kellgren-Lawrence scale grade 0 in six patients (33%), a grade I in eight (44%), a grade II in three (17%), and a grade III in one patient (6%). No patients were found with a Kellgren-Lawrence scale grade IV. No significant differences with pre-operative radiographies were found (chi-square = 1.867; df = 3; P = 0.60) in osteoarthritis development of the knee. Reported WORMS scores had an average of 12.4 ± 5.1. No recurrence of any cysts was observed. DISCUSSION: Different treatments for lateral meniscal cysts have been proposed, but proper management of the cyst is still controversial. The results of this study suggest that the outside-in needling of the cyst associated with partial meniscectomy is a highly effective, simple, and repeatable technique. Excellent clinical outcomes were reported at a mean follow-up of 11.6 ± 2.6 years (range 7-15). Imaging evaluation showed no significant evolution to osteoarthritis of the knee. CONCLUSIONS: Partial arthroscopic meniscectomy associated with percutaneous decompressive needling of the cyst wall under arthroscopic visualization showed positive clinical and radiological long-term results. Neither traditional radiographies nor innovative standing MRIs showed findings of osteoarthritis.

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.

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.

ACL reconstruction with hamstrings: how different technique and fixation devices influence bone tunnel enlargement.

BACKGROUND: Bone tunnel enlargement after anterior cruciate ligament (ACL) reconstruction is well documented in the literature. The cause of this tunnel enlargement is unclear, but is thought to be multifactorial, with mechanical and biological factors playing a role. AIM: The aim of this prospective study was to evaluate how the different techniques may affect the bone tunnel enlargement and clinical outcome. PATIENTS AND METHODS: Forty-five consecutive patients undergoing ACL reconstruction with autologous doubled semitendinosus and gracilis tendons entered this study. They were randomly assigned to enter group A (In-Out technique, with cortical fixation and Interference screw) and group B (Out-In technique, metal cortical fixation on the femour and tibia). At a mean follow-up of 10 months, all the patients underwent CT scan exam to evaluate the post-operative diameters of both femoral and they underwent tibial tunnels clinical examination after 24 months. RESULTS: The mean femoral tunnel diameter increased significantly from 9.05±0.3 mm to 10.01±2.3 mm in group A and from 9.04±0.8 mm to 9.3±1.12 mm in group B. The mean increase in femoral tunnel diameters observed in group A was significantly higher than that observed in group B (p < 0.05) The mean tibial tunnel diameter increased significantly from 9.03±0.04 mm to 10.68±2.5 mm in group A and from 9.04±0.03 mm to 10.±0.78 mm in group B. The mean increase in tibial tunnel diameters observed in group A was significantly higher than that observed in group B (p < 0.05). No clinical differences were found between two groups and no correlations between clinical and radiological results were found in any patients of both groups. CONCLUSIONS: Results of the study suggest that different mechanical fixation devices could influence tunnel widening. The lower stiffness of the fixation devices is probably responsible of the tunnel widening through the fixation devices's micromotions in the femoral and tibial tunnels.

Accuracy of manual instrumentation of tibial cutting guide in total knee arthroplasty.

PURPOSE: The aim of this study was to evaluate the accuracy of conventional instrumentation for tibial resection in total knee arthroplasty (TKA) as assessed by a computer-based navigation system during each phase of the surgical procedure. The hypothesis is that conventional instrumentation fails to achieve optimal accuracy in final implant positioning, thus leading to surgical errors. METHODS: Forty primary TKAs were performed. The resection guide was placed using an extramedullary guide. Accurate guide positioning was assessed by the navigation system prior to the osteotomy. The alignment measurement was repeated after resection and after component implantation in order to quantify the deviation caused by the manual positioning of the prosthetic components. A deviation ≥2° was considered unsatisfactory. RESULTS: In the frontal plane, unsatisfactory results observed were as follows: 15 % with reference to manual positioning of the resection guide and 10 % with reference to definition of the resection plane with a tendency towards varus malalignment. In the sagittal plane, unsatisfactory results were as follows: 45 % with reference to manual positioning of the resection guide and 40 % with reference to definition of the resection plane with a trend of decreased tibial slope angle. The deviation between bone resection and subsequent implant placement was ≥2° in none of the cases. CONCLUSIONS: The study confirms the hypothesis that conventional instrumentation fails to achieve optimal accuracy in the positioning of the tibial component. During each phase of the surgical procedure, a tendency towards varus malalignment and a decreased tibial slope angle were observed. LEVELS OF EVIDENCE: II.

Computer-assisted surgery: a teacher of TKAs.

INTRODUCTION: The hypothesis of this study is that computer-aided navigation experience could improve the ability to better place components in the coronal plane and to improve visual/spatial awareness based on the ability of navigation to provide instant feedback. The purpose of this study is to demonstrate the educational role of the navigation system to obtain a better alignment of the prosthetic components with standard instrumentation after a computer-aided navigation experience. MATERIALS AND METHODS: One hundred fifty patients were operated by the same surgeon, with more than 5 years experience with TKA. They were equally divided in three groups: group A (operated with non-navigated technique by surgeon without computer-assisted experience); group B (operated with computer-assisted surgery by the same surgeon); group C (operated with non-navigated technique by the same surgeon after the computer-navigated experience). We evaluated by full-length weight-bearing radiographs the overall alignment of the lower limb in the coronal plane. The optimum placement of the components was considered when the angle was within the limits of ±3° varus/valgus on the coronal x-rays. Comparison between groups was done using one-way ANOVA followed by post hoc Bonferroni test and Pearson chi-square statistics for proportions of optimum placement (P<0.05). RESULTS: In the group A 34 patients (68%) had the optimum placement on the coronal x-rays; in the group B they were 46 (92%) and in the group 41 (82%). The difference is statistically significant in comparing group A and Group B (<0.001), group A and group C (P=0.04), but not for group B and C (P=0.2). CONCLUSION: We believe that the navigation system has an educational role to improve the ability of surgeon of positioning prosthetic components precisely in the coronal plane.