Lower extremity performance following ACL rehabilitation
in the KANON-trial: impact of reconstruction and predictive value at 2 and 5

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,

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.

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

Related Posts:

Ericsson YB, Roos EM, & Frobell RB (2013). Lower extremity performance following ACL rehabilitation in the KANON-trial: impact of reconstruction and predictive value at 2 and 5 years. British Journal of Sports Medicine, 47 (15), 980-5 PMID: 24029859