Purpose of the study: Treatment of recent laxity of the posterior cruciate ligament is not standardized. The purpose of this work was to analyze results of reconstruction with adjunction of a synthetic ligament for major recent isolated or combined laxity of the posterior cruciate ligament (triades, pentades or dislocations). Our hypothesis was that the synthetic ligament acts like a tutor for healing of the torn ligament.
Material and methods: This retrospective analysis included 14 patients (1 woman and 13 men), mean age 27 years. All were competition athletes except one who did not practice sports. Three quarters of the patients were traffic accident victims. The series included three isolated posterior ligament tears, six combined laxities, and five knee dislocations. Average posterior laxity was 24 mm preoperatively. The procedure was performed 7 to 53 days after the accident. Arthroscopic reconstruction was performed for six patients and arthrotomy for eight. All associated lesions were repaired during the same procedure except for two cases (one anterior cruciate ligament and one popliteal tendon). Posterior cruciate ligament repair was achieved with the adjunction of a polyester ligament (LARS) using a one or two strand technique. Patients were reviewed at 36 months mean follow-up (10 - 88 months). The IKDC score was determined. A posterior drawer was measured manually with Telos at 70 degrees.
Results: Five stiff knees required either mobilization under anesthesia or arthrolysis. One tear occurred late after the accident during a new trauma. Subjectively, two patients were very satisfied, eight satisfied and three disappointed. Mean knee motion measurements were 6/0/130 degrees . A differential posterior drawer persisted in twelve knees. The Telos measurement of posterior drawer changed from a mean 24 mm to a mean 8 mm. The overall IKDC score was A: 0, B: 7, C: 3, and D: 2. Persistent posterior laxity was the predominant cause of poor scores. Outcome was less satisfactory for all items of posterolateral laxity. There was no difference between the 2- and 4-strand techniques. There were no cases of morbidity (synovitis, spontaneous tear) directly related to the synthetic ligament.
Discussion: The gain in posterior laxity was substantial. Results depended on associated lesions, particularly lateral involvement (stiffness, IKDC score) rather than the repair technique. The synthetic ligament appeared to play the role of a tutor: a single strand measuring 6 mm in diameter is sufficient. This technique spares tendon stock and could be proposed for major posterior cruciate ligament laxity. A longer follow-up will be necessary to confirm the durable stability.