Ericsson YB, Roos EM, and Frobell RB. Br J Sports Med. 2013; 47: 980-985.
Take Home Message: A patient with an anterior cruciate ligament (ACL) rupture will regain muscle strength and the ability to perform functional movements regardless of whether or not the ACL is reconstructed.
Despite nonsurgical treatment options, ACL reconstruction (ACLR) is the standard of care following an ACL rupture. Interestingly, the effect of ACLR on the muscle strength and functionality is not well understood. Therefore, Ericsson and colleagues completed a prospective cohort study to (1) compare muscle strength and functional performance after a standard rehabilitation protocol between patients with and without an ACLR. They also assessed if muscle strength and functional performance predict patient-reported outcomes at 2 and 5 years after injury or a delayed ACLR among patients that did not immediately receive an ACLR. This study was an ancillary study of the KANON trial, which is the only randomized controlled trial to directly compare both traditional ACLR and an optional delayed ACLR. The authors included 45 patients who had undergone ACLR within 10 weeks of injury (single bundle, patellar tendon or hamstring tendon grafts, performed by 1 of 4 senior surgeons) and 42 patients who were initially treated nonsurgically (23 patients went on to receive an ACLR at 31 to 244 weeks post injury). All patients completed a goal-oriented rehabilitation program, supervised by a single physical therapist. Following completion of all rehabilitation goals (~ 37 weeks post-injury) patients completed tests for muscle strength and functionality. All tests were completed using both the injured and uninjured sides. Tests performed were quadriceps and hamstring strength tests, 1-legged hop test, square hop test, vertical hop test, one-leg rise test, and closed eye one-legged balance test. The authors reported the tests results for each leg and in terms of the limb symmetry index (injured leg results/non-injured leg results x 100) with ≥ 90% defined as satisfactory. All patients also completed the Knee Injury and Osteoarthritis Outcome Score to assess subjective pain and function at 2 and 5 years post injury. Overall, there were no major differences in muscle strength or functional performance between the 2 groups. Performance of the vertical hop test and one-leg rise test were predictors of the need for delayed ACLR over 5 years and subjective pain and function at 2 and 5 years, respectively.
Overall, these results are intriguing because it highlights that we must be vigilant to always understand how our treatment decisions impact the patient in terms of time spent rehabilitating as well as the long-term implications on the patients overall health. The results presented here suggest that patients with and without an ACLR may have similar muscular strength and ability to perform functional movements at ~37 weeks post injury. Also interesting, is the concept that researchers may have found 2 tests (one-leg rise and vertical hop test) which clinicians could use to identify patients who may need an ACLR in the future, although more research is needed to verify this. Another intriguing concept that stems from this research is that perhaps the decision to undergo nonsurgical treatment would actually decrease the amount of time between injury and return to participation for at least some patients. While this is an inviting idea, more research must be completed to understand the long-term impact this will have on the joint. It would also be ideal in this situation to have a screening tool to decipher which patients respond best to this treatment. In conclusion, despite no strength or functional differences between patients with and without an early ACLR the vertical hop test may be a good clinical indicator of if the patient may need a delayed ACLR.
Questions for Discussion: Do you currently consider or counsel your patients on the potential merits of nonsurgical treatment of ACL injuries? If so, what indicators, if any, do you look or test for to see if the patient may respond favorably?
Written by: Kyle Harris
Reviewed by: Jeffrey Driban
Baseline Variables and Outcomes After ACL Surgery: The Swedish National Anterior Cruciate Ligament Register