Intraoperative injury to the medial collateral ligament (MCL) is a rare but important complication of total knee arthroplasty (TKA). Surgeons face two basic choices when it happens: intraoperatively converting to a more constrained TKA prosthesis, or primary repair of the MCL followed by protective bracing.
The retrospective review by Bohl et al. in the January 6, 2016 edition of The Journal of Bone & Joint Surgery does not compare those options head-to-head, but with an average follow-up of more than 8 years, it provides solid evidence that intraoperative repair followed by bracing is a successful long-term strategy.
The authors followed 45 TKAs that sustained either an intraoperative midsubstance MCL tear or an avulsion; 35 injuries occurred during a cruciate-retaining procedure, and 10 during a posterior-stabilized TKA. At a mean final follow-up of 99 months:
- There were no symptoms on physical examination of coronal-plane instability
- All patients were capable of community ambulation without an assistive device, and
- The mean HSS knee score had increased from 47 preoperatively to 85.
Five knees (11%) required intervention for stiffness. Although the authors emphasize that “in all cases the brace was set to allow full range of motion of the knee,” bracing may nevertheless have promoted stiffness by inhibiting range of motion in a cohort that included large proportions of obese and morbidly obese patients. This particular finding suggests that range-of-motion exercises should be emphasized after similar surgeries.
