Primary repair of intraoperative disruption of the medical collateral ligament during total knee arthroplasty.

BACKGROUND

Intraoperative disruption of the medial collateral ligament during total knee arthroplasty is an uncommon complication that is frequently treated by implanting a prosthesis with varus-valgus constraint. To our knowledge, no data have been published on primary repair or reattachment of the medial collateral ligament and implantation of a minimally constrained posterior-stabilized or cruciate-retaining prosthesis. This retrospective study evaluates the hypothesis that satisfactory clinical results, at a minimum of two years, can be achieved with immediate repair or reattachment of the medial collateral ligament and without a constrained total knee prosthesis.

METHODS

Of 600 knees treated with primary total knee arthroplasty, sixteen (in fourteen patients) sustained either a midsubstance disruption of the medial collateral ligament or an avulsion of the ligament from bone during the procedure. Preoperatively, all patients had either neutral or varus alignment and an intact medial collateral ligament. Midsubstance tears were treated with direct primary repair, and avulsions of the ligament off the tibia or femur were treated with suture-anchor reattachment to bone. All patients wore a hinged knee brace, with no limit to the range of motion, for six weeks postoperatively. Clinical and radiographic data were gathered prospectively as part of a database that was ongoing throughout the period of study; the cohort of patients was assembled retrospectively by searching that database.

RESULTS

No patients were lost to follow-up. The mean duration of follow-up was forty-five months (range, twenty-four to ninety-five months). The Hospital for Special Surgery knee scores increased from a mean of 47 points (poor) preoperatively to a mean of 93 points (excellent) at the time of final follow-up. On physical examination, no patient had a Hospital for Special Surgery score in the fair or poor range and all patients had regained normal stability in the coronal plane both at full extension and at 30 degrees of flexion. No patient required knee-bracing beyond the initial six-week postoperative period. The range of motion at the time of final follow-up averaged 108 degrees (range, 85 degrees to 125 degrees ), although one knee required manipulation under anesthesia to obtain a satisfactory range of motion. No arthroplasties required revision. Radiographic examination demonstrated appropriate limb alignment in all patients at the time of final follow-up.

CONCLUSIONS

Intraoperative disruption of the medial collateral ligament can be treated with primary repair or reattachment of the ligament to bone and postoperative bracing with good results; this avoids the potential disadvantages associated with the use of varus-valgus constrained implants.