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

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.

Conflict of interest: None.