Repair of Intraoperative Injury to the Medial Collateral Ligament During Primary Total Knee Arthroplasty

Background: Optimal treatment for intraoperative injury to the medial collateral ligament (MCL) during primary total knee arthroplasty remains controversial. While some advocate primary ligament repair and a period of bracing, others suggest conversion to a knee prosthesis with increased intrinsic constraint. The purpose of this study was to characterize the outcomes of primary repair followed by bracing.

Methods: We performed a retrospective review of consecutive primary total knee arthroplasties to identify patients with intraoperative MCL laceration or avulsion treated with primary repair. Midsubstance lacerations were treated with end-to-end suture repair, whereas a screw-and-washer construct, suture, and/or suture anchors were used for reattachment of avulsions. All patients were instructed to wear an unlocked hinged knee brace for six weeks postoperatively. Patients were evaluated at a minimum of two years postoperatively for evidence of instability or other modes of failure and complications.

Results: An intraoperative MCL injury occurred during forty-eight (1.2%) of the 3922 total knee arthroplasties that had been performed. One patient died less than two years postoperatively, one was lost to follow-up, and one underwent an intraoperative conversion to a constrained total knee arthroplasty, leaving forty-five total knee arthroplasties available for study. There were twenty-four midsubstance lacerations and twenty-one avulsions; thirty-five of these injuries occurred during a cruciate-retaining total knee arthroplasty and ten, during a posterior-stabilized total knee arthroplasty. At a mean of ninety-nine months (range, twenty-four to 214 months), there were no symptoms or physical examination findings of instability. The mean Hospital for Special Surgery knee score increased from 47 preoperatively to 85 at the time of follow-up (p < 0.001). Five knees required intervention for stiffness (four manipulations and one revision), and two required revision for aseptic loosening.

Conclusions: Our results suggest that intraoperative MCL injury can be treated with primary repair followed by hinged knee bracing without the need for increased prosthetic constraint. Stiffness, however, was a common complication.

Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.