Anterior Cruciate Ligament (ACL) reconstruction surgery is one of the most damaging experiences an athlete can go through. Although orthopedic surgical techniques have improved greatly in the past few decades, recovery is still slow (6 – 12 months) and re-injury rates for athletes are higher than most (20-40%)
It has been shown that the main reason for these high re-injury rates is lack of rehabilitation protocol completion before release to athletics. If an athlete does complete published protocols for ACL reconstruction return to play, their likelihood for re-rupture could reduce by 15%. Clearly the first thing therapists, trainers, coaches, and parents can do to ensure their athlete is best suited for return to play is to make sure they've completed standard protocols.
There are difficulties to this standard protocol methodology, however:
1: The protocols are difficult to achieve & assess: Challenging physical procedures exist within return to play protocols from ACL reconstruction including quality assessed single leg triple hop tests, single leg squats and change of direction.
Some practitioners make insufficient subjective analyses for appropriate release. Since assessing movement quality is subjective there is great variability from practitioner to practitioner in their ability and commitment to encouraging proper movements. The solution to this variability is utilization of a video posture analyzer but these units are expensive and inefficient and, therefore, hard to find.
Up to 70% of healthy athletes are unable to pass qualitative standards for ACL return to play. Specificity for return to play protocol completion is low because many athletes cannot complete the tests even without knee injury. Of those who do complete protocols, the best athletes are able to manipulate their performance to satisfy the test application rather than attaining quantifiable maximums. This means that the tests are better suited to determine which athletes have better mechanical values but not which athletes are better prepared for return to play. Indeed, in other assessment protocol, it has been shown that athletes who perform better on qualitative tests are more likely to become injured because their athletic prowess results in more playing time.
2: Return to play protocols rarely include equipment considerations: Most ACL injuries are non-contact. A significant number of non-contact ACL injuries occur due to improper footwear. On the field, wearing grass shoes on turf fields can greatly increase knee torque, and on the court, wearing non-court shoes can be just as detrimental.
Simply encouraging athletes to get the proper shoes can go a long way toward their re-injury prevention.
3: ACL "mechanism of injury" is poorly understood: Three main documented mechanisms of injury for an ACL rupture are:
Muscle weakness – Weakness is not an injury mechanism. Certainly it could be a precursor to ACL injury exposure but many people have general muscle weaknesses that don't result in injury.
Excessive Knee Valgus – It is unlikely that knee valgus is the mechanism or even the cause of ACL rupture. Indeed, the greater valgus a person experiences, the more flexible that individual's ligaments are. This doesn't mean that excessive valgus is desirable but it is more likely the result of injury not the injury mechanism. Instead, the true mechanical injury mechanism for ACL rupture is excessive tibial internal rotation. This rotation puts immediate tensile stress on the ACL. Coupled with some level of valgus, tibial internal rotation will cause the ACL to rupture. Tibial internal rotation is controlled by foot to ground contact integrity. If the foot is unable to mitigate ground contact forces, the heel will strike the ground hard. Respondent forces will transfer directly upward to the ankle joint which will twist (tibial internal rotation) before the ground force ever reaches the knee to cause valgus. Valgus is the result of ACL rupture, not the cause.
Skateboarders routinely land high jumps in positions of excessive valgus and never rupture their ACL because they make no heel impact and rotational torque is transferred through the wheels instead of the knees.
Assessing "Dominance" is complicated – It is well known that three biomechanical "dominance" factors often indicate increased risk for ACL rupture. These factors are ligament dominance, quadriceps dominance, and leg dominance. Presumably the dominance factors describe tendencies toward force production or reception during movement – particularly deceleration. Therapists and trainers will use subjective mechanical evaluations to determine if a risky dominance exists. Without an objective measure of force production or tensile strength to the accused tissues, it's difficult to deduce which dominance exists within which athletes. While it is possible to test for tissue dominance, it is expensive, time consuming, and not practical to implement on the vast majority of amateur athletes who suffer ACL injuries.
4: The Most Successful Protocol is Largely Ignored: There is only one recovery factor which consistently shows success in reducing ACL reconstruction re-injury. Time. Athletes who wait longer after surgery to return to high level activity have more success in minimizing re-injury than those who try to hurry the process. Surgical procedures and therapy processes have gotten good enough that they can get ACL sufferers back in action as quickly as 3 to 4 months. Indeed there is frequently competition between practitioners touting the ability to get athletes back to their desired play faster and faster. Data consistently show, however, athletes who complete return to play protocols and don't initiate unguided physical activity at least 9 to 12 months post-surgery have a significantly lower re-injury rate than all other variable measures.
Unfortunately patients can be impatient. They return to their activity too soon for appropriate tissue repair and re-education and put themselves into high risk situations.
By assessing the effectiveness of current return to play protocols from ACL reconstruction surgery, practitioners can better determine what factors will have a greater impact for reducing this injury's recurrence. Simple improvements like ensuring proper footwear, teaching appropriate ground contact, encouraging athletes to give appropriate time to recovering injuries, and improving overall athlete strength and conditioning will yield better results than the current 20-40% re-injury rates. We can be doing a better job, the question is will we.