Is Unicompartmental Arthroplasty an Acceptable Option for Spontaneous Osteonecrosis of the Knee?

Abstract

Background The literature suggests survivorship of unicompartmental knee arthroplasties (UKAs) for spontaneous osteonecrosis of the knee ranges from 93% to 97% at 10 to 12 years. However, these data arise from small series (23 to 33 patients), jeopardizing meaningful conclusions. Questions/purposes We determined (1) the longer-term survivorship of UKAs in a larger group of patients with spontaneous osteonecrosis of the knee; (2) their subjective, symptomatic, and functional outcomes; and (3) the percentage of failures and reasons for failures to identify relevant indications, contraindications, and technical parameters for treatment with a modern implant design. Methods We retrospectively evaluated all 84 patients with late-stage spontaneous osteonecrosis of the knee who had a medial UKA from 1998 to 2005. All patients had preoperative MRI to confirm the diagnosis, exclude metaphyseal involvement, and confirm the absence of major degenerative changes in the lateral and patellofemoral compartments. The mean age of the patients at surgery was 66 years and mean BMI was 28.9. We conducted KaplanMeier survival analysis using revision for any reason as the end point. Minimum followup was 63 months (mean, 98 months; range, 63-145 months). Results Ten-year survivorship was 89%. Ten revisions were performed; the most common reasons were subsidence of the tibial component (four) and aseptic loosening of the tibial component (three). No patient underwent revision for progression of osteoarthritis in the lateral or patellofemoral compartments. Conclusions Our data suggest spontaneous osteonecrosis of the knee may be an indication for UKA, provided secondary osteonecrosis of the knee is ruled out, preoperative

Minimally Invasive Unicompartmental Knee Arthroplasty for Spontaneous Osteonecrosis of the Knee

“…Ten revisions were performed; the most common reasons for failure being subsidence or aseptic loosening of the tibial component. No patient underwent revision for progression of osteoarthritis in the lateral or patellofemoral compartments. Similarly, Langdown et al .…”

“…Therefore, UKA seems to be an appropriate procedure, particularly for patients older than 60 years with unaffected lateral and patellofemoral compartments. Some surgeons believe joint arthroplasty is the only appropriate treatment for SONK with secondary articular collapse.…”

“…(C) Radiograph of the knee after UKA surgery. (d) UKA at 2.5 year follow-up on a long hip to ankle film.surgeons believe joint arthroplasty is the only appropriate treatment for SONK with secondary articular collapse12,13,15 .Recently, several studies have shown excellent functional outcome and survivorship of UKA after treating SONK.Bruni et al reported 84 patients with late-stage SONK with a mean follow-up of 98 months. The overall prosthesis survival was 89%.…”

Good survivorship of all-polyethylene tibial component UKA at long-term follow-up

“…All patients presented a varus deformity ( Table 2). All pre-and post-operative radiographic measurements were taken using a recognised technique [10]. Reason for revision was accurately documented based on radiographic and clinical evaluation and intra-operative direct inspection.…”

Early Failure in Medial Unicondylar Arthroplasty: Radiographic Analysis on the Importance of Joint Line Restoration

“…An independent observer (GR), expert in this field, blindly evaluated pre-and post-operative radiographs, measuring the femoro-tibial angle (FTA), tibial plateau angle (TPA) and posterior tibial slope (PTS): measurements were performed on digital A-P and lateral radiographs three times, on three different days, using previously reported techniques [38]. (Intra-observer variability, FTA = 0.87, TPA = 0.83, PTS = 0.80).…”