This prospective study evaluated the muscle strength recovery during a two year follow-up, assessed the relationship between different funtional outcome measurements and compared the outcome between younger(
$<$
25 years) and older (
$\geq$
25 years) patients. Progress in isokinetic muscle performance was measured at all follow-up intervals up to two years postoperatively. The Cincinnati functional score showed significant improvement between all follow-up intervals. Correlation analysis showed a significant relationship between the patients' subjective assessment of knee function and muscle strength and the triple jump test. The older age group had a significant slower recovery than the younger group up to one year postoperatively.
