Abstract
I never considered this to be a significant problem if it is noticed. (back to that later)
Aaron Rosenberg's report seems to have agreed, but at the last members meeting of the Knee Society, Boston, September 2009, others had experience that contradicted my view.
With their experience, ultimately the results were very substantially compromised. This video and presentation show you how to avoid a bad result, actually obtain a perfect result, if you or your student assistant, resident or fellow, bags the MCL.
There are three important points. (1) One needs to recognise the occurrence. (2) The setting is usually varus and so direct end-to-end repair cannot be depended upon. (3) Use of a semitendinosis tenodesis, together with an imperfect, distracted direct repair works perfectly well!
(1) Recognition: The setting is usually varus, but I have had one case in which the chief resident, working with the fellow succeeded in getting the MCL in a valgus knee! In this usually tight varus setting the key feature is that at some point in the case, before component placement, one notices that the exposure is all of a sudden better! Now, the guilty resident or just a passive assisting resident/fellow will usually disagree. The extension space is not so obviously lax, but the flexion space is. Secondly, you do not feel an intact ligament in flexion. And, to prove it I have had to do a little more exposure of the superficial MCL to show the tear. There are at least three mechanisms. Most common is a saw cut. Next is possibly injury with the scalpel or cutting cautery during exposure, and last is damage essentially pre-operatively by a very sharp medial osteophyte which has thoroughly abraded the ligament.
Laxity in full flexion is not necessarily obvious as the posterior capsular integrity helps hide the instability. Again, the really intact ligament is well felt, and in the situation of laceration, the tibia pulls forward more on the medial side, the medial flexion space opens, and what was usually a tight exposure gets suddenly better.
(2) When varus is the setting, I have found it impossible or at least uncomfortable to depend upon direct repair. When the soft tissues are needing to be released or simply undergoing more stress than usual and a lot more than on the lateral side, I see it as unwise to expect or depend upon only a medial repair to hold.
(3) The semitendinosis tenodesis has worked essentially perfectly in every one of my cases. These patients have had no post-operative instability and they have had better than average to extremely good ROM.
A presumably key point is not to alter the patient's post-operative regimen! And, to avoid some passive alteration of PT, I advise specifically that the surgeon or those in his/her team do not mention the occurrence to the patient, the family or the PT! I put the whole story in the op-note, and weeks later I will specifically tell the patient what the staple in place is all about.
