Intraoperative injury to the medial collateral ligament (MCL) is a rare but important potential complication of total knee arthroplasty (TKA). Our group recently published a retrospective review of 45 intraoperative injuries to the MCL that were managed with intraoperative repair (1). Specifically, for mid-substance lacerations, end-to-end suture repair was performed; for avulsions, screw/washer constructs or suture anchors were used for reattachment. Additionally, patients wore an unlocked hinged knee brace for 6 weeks postoperatively. The study included both posterior-stabilized  and cruciate-retaining  TKAs.
In our study, at a mean follow-up of 99 months, there were no subjective complaints or physical exam findings of instability. Mean Hospital for Special Surgery knee score increased from 47 preoperatively to 85 postoperatively. Five TKAs required intervention for stiffness (4 manipulations under anesthesia and 1 revision) and two required revision for aseptic loosening. Notably, in all three knees undergoing re-operation, the MCL was noted to be in continuity.
Overall, we believe that these findings suggest that management of intraoperative MCL injury with primary repair is a reasonable option. As Dr. Lee points out, additional constraint comes with the disadvantages of the potential for an increased polyethylene wear rate (2), increased stresses at the bone-cement/cement-implant interface (2-4), and removal of additional host bone stock. These potential disadvantages of increased constraint are not likely to display themselves until long-term follow-up—follow-up that neither our study nor studies using increased restraint have yet achieved. On the other hand, if failure of direct repair of the MCL were to occur, it might be expected to occur early. Moreover, an increase in articular constraint also typically increases the cost and complexity of the operation, and an implant with greater constraint may not always be available intraoperatively.
One apparent disadvantage of our protocol was postoperative stiffness, with several patients requiring manipulation and even revision surgery. Such results have not been reported in other series of direct repair. We attribute these findings in part to use of the hinged knee brace, which may have decreased mobility during the first 6 postoperative weeks. While all but two knees in our study eventually achieved 90 degrees of flexion, these findings do suggest a potential risk of postoperative bracing in this setting. Unfortunately, we do not know if the brace was necessary or critical to our overall good reported results.
Unfortunately there are no studies that directly compare primary repair of the MCL to increasing implant constraint. However, the available literature suggests that both are reasonable options with good supporting evidence for management of this complication. At the end of the day, the decision to attempt primary repair or convert to increased constraint may be based on the intraoperative findings, the quality of the soft tissues, the ability to repair the ligament, the experience of the surgeon, or even the availability of a constrained implant at the time of surgery. The next step in better understanding how to manage these injuries may be a prospective, randomized trial. However, the relatively rare occurrence of these injuries [reported at between 0.5% and 3% (1,3,5-7)] could make such a trial difficult to perform.
Conflicts of Interest: Dr. Bohl reports grants from MAOA, CSRS outside the submitted work; Dr. Della Valle reports personal fees from Depuy Orthopaedics Inc., Smith & Nephew, Zimmer-Biomet, CD Diagnostics, SLACK Inc., Wolters Kluver outside the submitted work; and he is a committee and/or board member of AAHKS, the Knee Society, the Hip Society, and Mid-America Orthopaedic Association.
- Bohl DD, Wetters NG, Del Gaizo DJ, et al. Repair of Intraoperative Injury to the Medial Collateral Ligament During Primary Total Knee Arthroplasty. J Bone Joint Surg Am 2016;98:35-9. [Crossref]
- Callaghan JJ, O'Rourke MR, Liu SS. The role of implant constraint in revision total knee arthroplasty: not too little, not too much. J Arthroplasty 2005;20:41-3. [Crossref]
- Hartford JM, Goodman SB, Schurman DJ, et al. Complex primary and revision total knee arthroplasty using the condylar constrained prosthesis: an average 5-year follow-up. J Arthroplasty 1998;13:380-7. [Crossref]
- Rosenberg AG, Verner JJ, Galante JO. Clinical results of total knee revision using the Total Condylar III prosthesis. Clin Orthop Relat Res 1991.83-90.
- Donaldson WF 3rd, Sculco TP, Insall JN, et al. Total condylar III knee prosthesis. Long-term follow-up study. Clin Orthop Relat Res 1988.21-8.
- Lachiewicz PF, Falatyn SP. Clinical and radiographic results of the Total Condylar III and Constrained Condylar total knee arthroplasty. J Arthroplasty 1996;11:916-22. [Crossref]
- Sculco TP. Total condylar III prosthesis in ligament instability. Orthop Clin North Am 1989;20:221-6.
Cite this article as: Bohl DD, Della Valle CJ. Repair: a viable option for management of medial collateral ligament injury during primary total knee arthroplasty. Ann Joint 2017;2:1.