Listened to your podcast on post-op knee rehab and read the article by Derek. It was great, thanks for the information. I understand the individualistic nature of rehabilitation and have taken a lot of key points away from both the podcast and article… However, is there any papers you recommend for referencing when the objective measures mentioned in the podcast should be hit? (i.e. at so and so weeks quad index of 80%, less than 15% difference in hop tests etc.). Or are these more general measures you’d want the athlete to hit prior to partaking in sports specific drills, and thus returning to practice… and not so much “you must have an 80% quad index before you run” (as an example).
There’s so many reviews out there, just wanting to make sure I am interpreting your information correctly and referencing the best available evidence. I’ve bookmarked the papers from Derek’s article.
Hey Alex, so there is a lot to this and I will try and be thorough in my response as a lot of these recommendations are based way more on opinion than clinical evidence and there are layers to each. I’m going to take these point by point with some general comments as well.
Indexes in general
I do think there is utility in indexes but there are a few problems with them as they can most certainly give a false sense of security. First, there is the assumption that uninjured athletes can pass the expected indexes as well and there was a paper from Greenburg last year that would question if that is the case. If “normal” athletes cannot pass the criteria we may need to evaluate what constitutes “normal” for return to sport. If you have an athlete that is generally weak that can also inflate your LSI as you are comparing a weak leg to a weaker leg. This is why you started seeing some recommendations come out in terms of strength to bodyweight. But even here it almost becomes the “screening” question of where to we draw the line. There is a very recent paper from Iwame the put the number at 1.45nm/Kg testing with an isokinetic dynamometer. That of course is operating under the assumption that a clinic 1) has an isokinetic dynamometer 2) uses said dynamometer. Unfortunately, there are some other papers from Greenburg that state most only use MMT for which and index is worthless. What is interesting is we have all of these papers arguing which graft is better looking at index outcomes that seem to forget that the rehab has way more influence on functional recovery than anything that happens in surgery. Turns out for the most part, we just suck at rehab. The Toole paper is the go to for this demonstration. In the introduction of this paper you will also find many of the references to different opinions on strength indexes.
Part of this is also related to what passing these indexes allows an athlete to do. I would likely take the stance that return to competition should not happen prior to nine months just from what we know on the religamentization process. The index can used as a barometer for the introduction of sport specific drills, practice activities, then competition. But this is also contingent on what sport the athlete plays and even then the demands of their unique position i.e. a cornerback has entirely different COD demands than a basketball center. But the center can likely start working on their jumper from a stationary spot long before doing any COD drills (or I would argue even running).
Strength Indexes
I will circle back to the set of Greenburg papers on how both surgeons and PTs (in their paper it was OCS and FAAOMPT which should mean those individuals know better) do not adequately assess strength. Not many centers have an isokinetic dynamometer but there does need to be some metric in place as a proxy. The isometric testing is getting more popular but I have not seen any paper with true norms set. I try and base the 80% number off 1) an isokinetic dynamometer at 60 deg/sec 2) isometric testing 3). OKC knee extension 4) Leg press in that order of what I have access to. That being said, if an athlete is kicking out 50% of bodyweight on their nonsurgical leg, I don’t care if they are 100% LSI I’m probably holding off on some higher level activities. This gets harder to discern without some form of dynamometer though.
Hop tests
Here I think there is some nuance in when jumping/landing/COD gets introduced. We tend to treat some of these timelines like something magically happens that makes it okay to start jumping/landing at 12 weeks when we should probably start exposing athletes to forms of these drills earlier on. If an athlete has not jumped in 3 months and we hop test them there is probably as much a “learning effect” there as anything to do with strength/biomechanics. Plus, all of our tests are pretty linear in the normal battery. That’s great, except plenty of sports have athletes jumping in different directions so I don’t know how much we are really getting out of that information.
I say all of this to end with “most of this is based on opinions of clinicians and this is really complex.” We are actually submitting to present on this exact topic as CSM next year so we’ll see if it gets accepted or if we need another year of “neuromuscular control drills” s/p ACL reconstruction.
Thank you for taking the time to post this thorough and prompt response, you have clarified a lot of my uncertainties. It’s interesting how “linear” RTS programs for post-operative care seem to be marketed as… like you said, it’s as if athletes are to go to bed one night and wake up the next day magically be ready to perform jumping tasks/objective tests with minimal to no prior graded exposure. Suppose it highlights the ambiguity to rehab as it pertains to each individual surgery and person, as not one cookie cutter program will work the same for everyone… let alone the same person twice.