Aim: To study the influence of anterior cruciate ligament (ACL) deficiency upon functional outcome after Coventry high tibial osteotomy, four to seven years after the surgery.

Method: One hundred and thirty-five patients (142 knees) each underwent a Coventry high-tibial osteotomy with staple fixation, performed by a single surgeon for medial arthrosis of the knee. During the study period, six patients (seven knees) proceeded to total knee arthroplasty and three patients died from unrelated causes. Nine patients were lost to follow-up. Comparisons were drawn between those patients with an intact ACL (ACLi) and those with ACL deficiency (ACLd).

Results: One hundred and seventeen patients (122 procedures) were available for review (100 males, median age 49 years, range: 29years to 70 years). The median follow up period was 64 months (range 37 to 80 months). The ACLd group was significantly younger (median age was 44 versus 51, p< 0.05) and reported significantly less pain and difficulty with stairs, shopping and rising to stand than the ACLi group. Seventy-eight percent of ACLd patients underwent previous surgical procedures on the affected knee. Ninety-six percent of the ACLd group and 89% of the ACLi group were either enthusiastic or satisfied with the outcome of the surgery. The mean Knee Society Score was 83 and 79 (respectively). All six revisions of the knee arthroplasties were in the ACLi group.

Conclusions: High tibial osteotomy was performed at a younger age for those patients with an absent anterior cruciate ligament. These patients had a subjectively better functional medium-term outcome, despite having had a greater number of surgical procedures prior to the osteotomy and having an ACL-deficient joint.