Fixed-Bearing Medial Unicompartmental Knee Arthroplasty in Patients Younger Than 55 Years of Age at 4-19 Years of Follow-Up: A Concise Follow-Up of a Previous Report

• Published in: The Journal of arthroplasty 2021-03, Vol.36 (3), p.917-921
• Main Authors: Calkins, Tyler E., Hannon, Charles P., Fillingham, Yale A., Culvern, Chris C., Berger, Richard A., Della Valle, Craig J.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; arthroplasty; Arthroplasty, Replacement, Knee - adverse effects; Child; Child, Preschool; Follow-Up Studies; Humans; knee; Knee Joint - diagnostic imaging; Knee Joint - surgery; Knee Prosthesis; medial; medial fixed-bearing arthroplasty; Middle Aged; Osteoarthritis, Knee - surgery; Retrospective Studies; Treatment Outcome; unicompartmental arthroplasty; Young Adult; young patients
• ISSN: 0883-5403; 1532-8406
• DOI: 10.1016/j.arth.2020.09.042

Unicompartmental knee arthroplasty (UKA) is an effective alternative to total knee arthroplasty (TKA) in isolated unicompartmental disease; however, mid-term to long-term results in young patients are unknown. The purpose of this study is to determine the mid-term outcomes of fixed-bearing medial UKA in patients less than 55 years of age. Seventy-seven fixed-bearing medial UKAs in patients less than 55 years of age (mean 49.9, range 38-55) from a previously published report were retrospectively reviewed at a mean follow-up of 11.2 years (range 4.1-19.2). Eleven knees were converted to TKA (14.3%) at 0.7-13.8 years postoperatively. The indications for revision included 7 for unexplained pain (9.1%), 2 for grade 4 arthritic progression (1 isolated lateral and 1 lateral and patellofemoral compartments; 2.6%), 1 for polyethylene wear (1.3%), and 1 for femoral component loosening (1.3%). Predicted survivorship free from component revision was 90.4% (95% confidence interval 86.9-93.9) at 10 years and 75.1% (95% confidence interval 66.2-84.0) at 19 years. The mean Knee Society Score improved from a mean of 51.9-88.6 points (P < .001). Of the 52 knees with 4-year minimum radiographs, 3 (5.8%) developed isolated grade 4 patellofemoral arthritis that was asymptomatic, and no knees had evidence of component loosening or osteolysis. Fixed-bearing medial UKA is a durable option for young patients with unicompartmental arthritis, with good clinical outcomes at mid-term follow-up. Unexplained pain was the most common reason for revision to TKA.