Preoperative Predictors for Noncopers
to Pass Return to Sports Criteria After ACL Reconstruction.

Hartigan EH,
Zeni J, Di Stasi S, Axe MJ, and Snyder-Mackler L. J Appl Biomech.

Following anterior
cruciate ligament (ACL) rupture, it is often suggested that an athlete may be
able to return to sport 6 months post-surgery, regardless if the athlete is a
coper (can continue high-level activates without needing an ACL reconstruction)
or noncoper (lacks the ability to stabilize and limit instability without reconstruction).
This timeframe, however, has never been verified through a prospective study.
Therefore, Hartigan and colleagues completed a study to determine which
preoperative variables predict the ability of a noncoper to return to sport at
6 months. The study also sought to determine if patients who had strength gains
preoperatively would have better outcomes postoperatively. Patients were
eligible for inclusion if they were classified as a noncoper (classification
completed by a physical therapist), 15-55 years old, either contact or
non-contact ACL rupture confirmed by magnetic resonance imaging, 3 mm or
greater anterior translation between limbs using a KT-1000 arthrometer, and
were within 10 months of injury. A total of 38 patients (11 females, 27 males,
mean 28.6 year old) attended 10 preoperative physical therapy sessions. Rehabilitation
consisted of isotonic and isokinetic quadriceps strengthening exercises (wall slides,
step exercises, etc). Three months following ACL
reconstruction and after meeting 4 clinical milestones (knee effusion of grade
1 or less, full knee range of motion, quadriceps strength index of at least
80%, and no pain with hopping while braced) athletes were allowed to attempt to
pass return to sport criteria. Return to sport criteria consisted of 90% quadriceps
strength symmetry between injured and noninjured limb and a score of 90% on
both the KOS-ADLS and global rating scale. Gait
analysis was performed in each patient using a three-dimensional, eight-camera
motion analysis system and force platform. Quadriceps force measurements were
recorded with a maximum, isometric contraction on a dynamometer. Overall, age,
quadriceps strength, and knee flexion moments during gait on the involved limb
were significantly different between those who passed and failed the return to
play criteria. The results demonstrated older patients, patients with weaker
quadriceps, and patients with less knee flexion during walking were less likely
to pass return to sport criteria. When considering age, quadriceps strength,
and knee flexion moments the authors could correctly predict 69% of the patients
who passed and 82% of patients who failed to meet the return to sport criteria
at 6 months post ACL reconstruction. Improved quadriceps strength after
physical therapy was also significantly predictive of return to activity at 6

these results are important for clinicians to be aware of when determining
return to sport rehabilitation and timeframes. Perhaps this data is most useful
as a guide to clinicians on what factors to focus on the most, in hopes of
returning their athletes to play. While age is not a modifiable factor and
debate exists over how modifiable knee flexion moments during gait are, the
major focus of preoperative rehabilitation should focus on increasing
quadriceps strength. Furthermore, future research should explore how these
factors would influence passing or failing return to sport during more sport
specific activities (running, cutting, etc.). While age is not modifiable, it
is a significant predictor of an athletes’ ability to pass return to sport
criteria, and should be something which clinicians discuss with their athletes
both pre and post-surgery to develop more appropriate return to sport timelines
for the individual athlete. Tell us what you think. What factors do you focus
on preoperatively with your ACL reconstruction patients? Do you counsel your
patients on unmodifiable factors, such as age, and discuss how that factor may
impact the overall recovery timeline?

Written by:
Kyle Harris
Reviewed by:  Stephen Thomas


Hartigan EH, Zeni J Jr, Di Stasi S, Axe MJ, & Snyder-Mackler L (2012). Preoperative Predictors for Noncopers to Pass Return to Sports Criteria After ACL Reconstruction. Journal of Applied Biomechanics, 28 (4), 366-73 PMID: 22983930