Anterior knee pain following ACL reconstruction

1. Anterior knee pain (AKP) is a potential complication of ACL Reconstruction (ACLR) with hamstring tendon (HT) autograft.

2. Patients with AKP following ACLR with HT autograft have decreased isokinetic strength and functional pain 4 months post-operatively, but not at 7 months, compared to patients without AKP. 

Evidence Rating Level: 2 (Good)

Anterior knee pain (AKP) following anterior cruciate ligament reconstruction (ACLR) is a common complaint, with an estimated prevalence of 2.7 to 20%, more often seen in patellar tendon (PT) autografts than hamstring tendon (HT). AKP can increase the risk of deficits in quadriceps and hamstring strength, but the functional repercussions of AKP are not well-elucidated, particularly for HT autografts. Therefore, this cohort study compared patients with and without AKP after an HT ACLR, in terms of isokinetic knee strength and functional outcomes, at 4 and 7 months post-operation. The study population consisted of 330 patients from a single centre in France, undergoing ACLR between 2015 and 2020. Patients were divided into AKP and no AKP groups at 4 months post-op. At follow-up, the outcomes were measured using the limb symmetry index (LSI) for knee extensors and flexors, and the 100-point Lysholm score for functional rating of pain during activity. The results showed that AKP was reported in 14.8% of patients. At 4 months, the quadriceps LSI at 60°/s and 180°/s, and the hamstring LSI at 60°/s were significantly lower in the AKP group (p < 0.05), whereas the hamstring LSI at 180°/s was not different between the groups (p = 0.32). The Lysholm score was significantly lower in the AKP group as well (85.4±9.4 vs 96±7.2, p < 0.05). At 7 months however, there were no significant differences in LSI of the quadriceps or hamstring at 60°/s and 180°/s, and no difference in Lysholm score (93.1±6.3 for AKP vs 91.3±7 for no AKP, p = 0.17). Overall, this study demonstrated that AKP can be a complication of ACLR with HT autograft, and is associated with decreased isokinetic strength and functional pain at 4 months post-operatively, but not at 7 months.

Click to read the study in PLOSONE

Image: PD

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