What Do I Do if I Cut the MCL?
In the abstract from his presentation at ICJR’s Pan Pacific Orthoapedic Congress, Dr. Craig Della Valle offers advice on managing intraoperative laceration or avulsion of the medial collateral ligament.
By Craig J. Della Valle, MD
Intraoperative laceration or avulsion of the medial collateral ligament (MCL) is a known complication of total knee arthroplasty (TKA). Although this is a relatively rare complication, it has been reported to have a prevalence of up to 8% in certain high-risk groups such as morbidly obese patients.
How Do I Identify the Problem?
Incompetence of the MCL can be surprisingly difficult for the surgeon to recognize. Signs that the MCL has been cut or avulsed include:
- Acute increase in surgical exposure
- Knee accommodating thicker and thicker polyethylene liner trials
- Knee still feeling unstable
- Gross laxity observed on the medial side
What Do I Do If I Think This Has happened?
Try to determine if the MCL has been lacerated at the joint line (usually secondary to the saw when cutting the proximal tibia) or avulsed from its insertion (almost always occurs off of the tibial insertion).
If you have a joint line laceration, identify the proximal and distal ends if you can. Primarily repair them to one another (if you can) with a running, locking stitch placed in either side. You can augment this repair with autograft, allograft, or synthetic graft-type material.
If you are not confident in your side-to-side (or end-to-end) repair, the other option is to capture the proximal (femoral) side of the lacerated MCL and repair it over a post and washer into the proximal tibia. This usually provides robust fixation.
If you have an avulsion form the proximal tibia, capture the proximal (femoral) side of the MCL and repair it over a post/washer placed into the proximal tibia or use suture anchors.
What is controversial is whether the use of a knee with varus/valgus constraint is necessary or whether a primary repair alone is adequate. My bias is that the MCL has excellent healing potential, and in my experience, a lacerated or avulsed MCL heals reliably.
Leopold et al  reported on 16 lacerations of the MCL treated with primary repair and a hinged knee brace for 6 weeks. All lacerations healed. Our present experience with primary repair (Del Gaizo et al, AAOS 2012, unpublished) includes 45 knees with no failures.
Although increased constraint is attractive, in general it is a more expensive, more complicated, and more costly solution.
How Do I Prevent This From Happening?
- Careful exposure on the medial side of the knee including a release around the postero-medial corner to allow for a retractor to be placed in the interval between the MCL and the proximal tibia during the tibial cut
- Careful use of the saw during the tibial cut
- Avoid levering on the MCL to protect against an avulsion
Craig J. Della Valle, MD, is Professor of Orthopaedic Surgery at Rush University Medical Center, Chicago, Illinois.
- Leopold SS, McStay C, Klafeta K, Jacobs JJ, Berger RA, Rosenberg AG. Primary repair of intraoperative disruption of the medical collateral ligament during total knee arthroplasty. J Bone Joint Surg Am. 2001 Jan;83-A(1):86-91.