Abstract
Anterior cruciate ligament reconstruction has become a standard procedure with a documented good and excellent outcome of 70–90%. Important variables of outcome after surgery consist of objective and subjective variables. It is important to examine the relationship between commonly used knee rating systems and functional tests to assess whether there is a correlation between rating systems and functional performance. The purpose of this study was to determine if a correlation exists between four commonly used knee rating systems (Lysholm, Tegner, IKDC, Noyes) and commonly performed dunctional tests: single and timed hop, vertical jump and isometric, isokinetic and eccentric muscle strength.
44 consecutive patients (31 males and 13 females) were selected (mean age 27.9 years). All subjects were tested prior and 12 month following anterior cruciate ligament reconstruction. The subjects completed the above knee rating scores. The patients were then evaluated performing the following tests: single leg hop for distance, timed hop and vertical jump. Muscle strength was assessed using a Biodex dynamometer. Isometric strength was examined at 30 and 60 degrees of flex-ion. Isokinetic testing (concentric and eccentric) was performed at 120 and 180 degrees/sec. Their results of functional testing were expressed as percentage of the contralateral non involved limb.
A positive correlation was found between single leg hop, Lysholm (r=0.53, p< 0.05). IKDC (r=0.30, p< 00002) and Noyes score (r=0.45, p< 0.01). A positive correlation was found between vertical jump, Lysholm (r=0.21, p< 0002), IKDC (r=0.31, p< 0.0001) and Noyes score (r=0.31, p< 0.0001). There was no correlation between timed hop and knee scores. A negative correlation (r=0.25–0.46) was noted between eccentric peak extension torque at 120 degrees/sec and 180 degrees/sec (r=0.230.26). However it only reached significance (p< 0.04) between IKDC and eccentric torque at 120 degrees/sec and 180 degrees/sec (p< 0.01). In addition there was a moderate negative correlation (r=0.26, p< 0.0004)) between Lysholm score and eccentric peak torque at 180 degrees/sec. No correlations were found for isokinetic and isometric torque for the knee flexors.
Knee rating systems seem to reflect functional capabilities and subjective satisfaction of patients prior and post ACL reconstruction. Isokinetic strength does not seem to be an important predictor of knee function.
The abstracts were prepared by David AF Morgan. Correspondence should be addressed to him at davidafmorgan@aoa.org.au
Declaration of interest: a
