Enlightenment on Knee Flexors Strength Loss in Cases of Posterior Knee Pain After Anterior Cruciate Ligament Reconstruction.

Abstract

The persistence and the recurrence of posterior medial knee pain (PKP) after anterior cruciate ligament reconstruction (ACLR) using hamstring tendon graft are often overlooked during rehabilitation. Cross-sectional observational study. The study aimed (1)to evaluate the prevalence of these types of PKP before 4months post-ACLR, (2)to measure their consequences on the knee flexors strength, and (3)to evaluate the role of the type of ACLR. From a cohort of patients operated on with hamstring tendon procedures, the persistent and the recurrent PKP were sought at 4months post-ACLR. The evolution of isokinetic muscle strength recovery in PKP subjects was compared with those of nonpainful subjects. The functional deficit was measured at 6/7months post-ACLR by a hop test. Three hundred seventeen subjects (25.8 [6.0]y) were included. At 4months post-ACLR, 2 populations were identified based on the recurrent onset of PKP (PKP+, n = 40) or the absence of knee pain (PKP-, n = 277). The prevalence of PKP was 8.3%. At the fourth month post-ACLR, the PKP+ group had a higher flexor strength deficit compared with the PKP- group (limb symmetry index at 60°/s: 67.2% [12.4%] vs 84.3% [12.6%]; P < .05). At 6/7months, the loss of strength persisted (limb symmetry index at 60°/s: 82.3% [13.4%] vs 87.7% [12.8%]; P < .05). The hop test deficit was comparable, and no difference was shown according to the type of graft. Persistent and recurrent PKP during the rehabilitation period were not uncommon and were associated with a worsening of flexors strength loss on the ACLR side.