Archives of Orthopaedic and Trauma Surgery - 2026-03-30 - Journal Article
Lateral unicompartmental knee arthroplasty through a medial parapatellar approach: surgical technique and mid-term results in 108 patients.
Leggieri F, Braconi L, Chirico M, Salari P, Baldini A
Topics
Key Takeaway
Lateral UKA via medial parapatellar approach achieved 97.2% 7-year survivorship with 99.0% of patients meeting KSS-Knee PASS thresholds at mean 47.6 months in 108 patients.
Summary Depth
Choose how much analysis to show on this article page.
Summary
This single-surgeon retrospective series evaluated implant survivorship and functional outcomes of lateral UKA performed through a medial parapatellar approach in 108 patients between 2016 and 2023. Four failures occurred (3.7%): two OA progression, one aseptic loosening, one periprosthetic fracture; 7-year survivorship was 97.2% (95% CI 94.2–100%). PASS thresholds were met by 99.0% for KSS-Knee and 86.1% for KSS-Function, with older age independently predicting failure to achieve functional PASS (OR 1.3/year, p=0.036).
Key Limitation
Absence of a concurrent lateral parapatellar approach control group makes it impossible to attribute the outcomes to approach selection rather than surgeon experience or patient selection.
Original Abstract
INTRODUCTION
Lateral unicompartmental knee arthroplasty (L-UKA) is typically performed through a lateral parapatellar approach. Few studies of L-UKA performed through a medial approach are published. We aimed to present surgical tips, and mid-term clinical results and survivorships of L-UKA performed through a medial approach.
METHODS
We retrospectively reviewed single-centre single-surgeon data from L-UKA using medial parapatellar approach between 2016 and 2023. Patients with follow-up < 12 months were excluded. Primary endpoint was implant survivorship (time from index surgery to revision or last follow-up). Secondary endpoints included the rates of patients achieving Patient Acceptable Symptom State (PASS) thresholds: ≥ 67.5 for Knee Society Score-Knee (KSS-K) and ≥ 70.5 for Knee Society Score-Function (KSS-F). Survival analysis was used for implant survivorship. Logistic regression was performed for factors potentially associated with failure to achieve the PASS thresholds. Significance was set at P < 0.05.
RESULTS
Among 110 patients initially identified, two died before 12-month follow-up and were excluded from clinical outcome analysis, leaving 108 patients for functional assessment at a mean 47.6 months ± 24.5 of follow-up (range 12–96.7 months). No complications were reported during hospitalization. There were four failures (3.7%) overall: two cases (1.8%) of OA progression, one (0.9%) of aseptic loosening, and one case (0.9%) of periprosthetic fracture of the medial condyle requiring revision surgery. All 110 patients were included in survival analysis, with the 2 patients who died before 12 months included as censored data at time of death. The overall 7-year survivorship was 97.2% (95% CI 94.2–100%), declining to 92.1% at 84 months when the last revision occurred. PASS thresholds were achieved by 99.0% patients for KSS-Knee and by 86.1% for the KSS-F. Patient age was a significant predictor of failure to achieve functional PASS thresholds (OR = 1.3 per year, 95% CI 1.0–1.6, p = 0.036).
CONCLUSIONS
L-UKA performed through a medial parapatellar approach yielded excellent clinical outcomes and survivorship at mid-term follow-up.
LEVEL OF EVIDENCE
IV (retrospective case series).