This study aims to evaluate and compare the functional outcomes and survival rates of unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) with an external fixator for medial compartment osteoarthritis (OA).
Two cohorts of patients aged less than 60 years who had undergone either a cemented medial mobile-bearing UKA or an HTO with an external fixator were included in the study. The first cohort consisted of patients undergoing a series of 197 consecutive medial UKA procedures (UKA group). The second cohort consisted of 60 consecutive patients undergoing HTO with an external fixator (HTO group).
Each patient was evaluated based on the Oxford Knee Score (OKS), the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Subjective International Knee Documentation Committee (IKDC) score/questionnaire. A clinical evaluation was conducted on the day of the surgery (T0) and at the follow-up visit (T1) (minimum follow-up time was 60 months). Complications and failures resulting from the surgery were recorded for each patient.
Only the age of the patients at the pre-operative time differed significantly between the two groups, with the HTO group being significantly younger (47.78 ± 8.01 versus 55.88 ± 2.28).
After the final follow-up visit, all clinical scores improved significantly in both groups (p < 0.05).
IKDC and Oxford scores were higher for the UKA group (p < 0.05). In the HTO group, three complications occurred (5%), including two superficial infections and one deep infection. On the other hand, the UKA group reported four complications (2%): three aseptic mobilisations and one infection requiring revision surgery. There were no statistically significant differences between the two groups in terms of the complication rate (p = 0.208)
In young patients (< 60 years) with an isolated medial knee (OA), both HTO and UKA led to good to excellent clinical results with a low rate of complications at mid-term follow-up; both surgical procedures may be considered in this patient population, but further long-term follow-up is needed.