Functional results and survivorship after medial unicompartmental knee arthroplasty: A single center experience from Saudi Arabia

Abstract

BACKGROUND: Isolated involvement of the medial compartment of the knee in degenerative disease is encountered in about 25% of patients with gonarthrosis. We aim to show that in a well-selected group of such patients, medial unicompartmental knee arthroplasty (UKA) is a good option. OBJECTIVES: Review the functional outcomes of patients undergoing UKA and determine the long-term survivorship of the implants and complications of the procedure. DESIGN: Analytical retrospective chart review. SETTING: Academic tertiary care medical center and tertiary care private hospital in the western region of Saudi Arabia. PATIENTS AND METHODS: We selected patients who underwent medial UKAs by the same surgeon between December 1988 and December 2009. The life table approach and the Kaplan-Meier statistical method were used to estimate the survival rate (5-30 years) with revision as the endpoint. Functional outcome scores were determined according to the Knee Society Clinical Rating System. MAIN OUTCOME MEASURES: Change in performance scores for pain, walking, and range of movement. Survivorship of the implants with removal of the implant as the endpoint; post-operative complications. SAMPLE SIZE: 218 implants on 142 patients. RESULTS: The survival rate of UKA was 94.7% at 10 years (95% CI 0.906-0.970), 80.9% at 20 years (95%CI 0.724-0.871), and 77.8% at 30 years (95%CI 0.669-0.855). The average grand total functional score increased from 61 (maximum 200) at 0 months to above 150 at ≥6 months. CONCLUSION: UKA is a good option for isolated medial compartment gonarthrosis with excellent functional outcome and good survivorship in selected patients. LIMITATION: Single center experience, retrospective. We lost 6.0% of patients during follow-up. Comparison with other treatment modalities is based on literature review and not on our own data.