ACL deficiency and varus osteoarthritis: high tibial osteotomy alone or combined with ACL reconstruction?

This study investigates the mid- to long-term clinical and radiological outcome in patients with symptomatic varus osteoarthritis (OA) and deficiency of the anterior cruciate ligament (ACL) and analyzes whether there are differences between isolated high tibial osteotomy (HTO) or combined single-stage HTO and ACL reconstruction (ACLR).

26 patients who underwent HTO alone (group 1) and 26 patients who underwent single-stage HTO and ACLR (group 2) because of varus OA and ACL deficiency were examined at a mean of 5.8 years (SD 3.6 years) post-operatively. Assessment at follow-up (FU) was performed using a questionnaire including clinical scores (Lysholm, IKDC) and the KT-2000 arthrometer to examine anterior knee stability. Radiographic knee alignment and signs of OA according to the classification of Kellgren and Lawrence (KL) were assessed pre-operatively and at FU.

Eighty-one percent of all patients reported an improvement of pain and 79% an improvement of instability without significant group difference. Significant worse results were observed in group 1 for the Lysholm score (group 1: 69.4, SD 15.7; group 2: 78.3, SD 16.4; p = 0.020) and the IKDC score (group 1: 64.8, SD 13.0; group 2: 74.0, SD 15.6; p = 0.006). No group difference was found for the KT-2000 examination. A significant post-operative increase of radiographic OA could be seen in both groups without significant group difference (KL pre-operative: 2.3, SD 0.63; KL FU: 2.8, SD 0.74; p < 0.001). The radiographic leg alignment at FU showed a significant lower valgus alignment in group 1 (group 1: 0.4 degree, SD 3.3 degree; group 2: 2.1 degree, SD 2.1 degree; p = 0.039). The rate of post-operative complications was low with 4%, and no significant group differences were found.

This study shows that HTO alone can improve pain and even subjective knee stability. Additional ACLR was in the mid term not associated with a higher increase of OA or a higher rate of post-operative complications in our study collective.