Clinical Results of Lateral Unicompartmental Knee Arthroplasty: Minimum 2-Year Follow-up

Abstract

BackgroundWe investigated the clinical results and early complications after lateral unicompartmental knee arthroplasty (UKA) using the Zimmer unicompartmental high-flex knee (ZUK) prosthesis with a minimum follow-up of 2 years.MethodsTwenty-seven patients (30 cases) who underwent lateral UKA with the ZUK prosthesis between January 2011 and February 2014 were selected for this study. The mean age of the patients was 63.3 years at the time of surgery, and the mean followup was 3 years and 2 months (range, 24 to 48 months). A retrospective investigation method was used to evaluate the clinical and radiographic results with use of the Knee Society (KS) clinical rating system and plain radiography.ResultsThe mean KS pain score was improved from 17.9 points (range, 10 to 30 points) preoperatively to 40.5 points (range, 30 to 45 points) at the final follow-up (p < 0.001). The mean KS knee score and function score significantly increased from 63.2 points (range, 48 to 70 points) and 68.6 points (range, 35 to 80 points), respectively, preoperatively to 86.0 points (range, 74 to 95 points) and 92.4 points (range, 60 to 100 points), respectively, at the final follow-up (p < 0.001). The mean range of motion of the knee was recovered from 127.1° (range, 110° to 135°) preoperatively to 131.6° (range, 120° to 135°) at the final follow-up. The mean tibiofemoral angle changed from 6.2° of valgus (range, 0.1° to 11.4° of valgus) preoperatively to 3.4°of valgus (range, 0.2° to 9.5° of valgus) at the final follow-up. The overall results classified based on the KS knee score were "excellent" in 21 cases and "good" in 8 cases. Revision total knee arthroplasty was required in one case because of consistent pain on the medial side of the knee after surgery.ConclusionsThe early clinical results of lateral UKA using the ZUK prosthesis were satisfactory for improvement of pain, knee score, function score, and recovery of knee motion. Therefore, the lateral UKA could be a useful method in the treatment of osteoarthritis in the lateral compartment of the knee. Long-term survivorship remains to be confirmed through ongoing follow-up.

Disease progression, aseptic loosening and bearing dislocations are the main revision indications after lateral unicompartmental knee arthroplasty: a systematic review

“…Data from 32 studies were available to compare mobile-bearing vs. fixed-bearing implants; 10 studies (n ¼ 2,268) with mobile-bearing implants [14,18,28,32,33,37,38,41,50,53], 18 studies (n ¼ 1,469) with fixed-bearing [8,26,[42][43][44][45][46][47][48][49]27,30,31,[34][35][36]39,40] and 4 additional studies that reported outcomes for both (n ¼ 1,743 mobile-bearing, n ¼ 790 fixed-bearing) [25,29,46,51]. 18 studies had a moderate risk of bias [8,18,[44][45][46][47][48][49][50]53,26,31,33,34,37,39,42,…”

Early results of fixed-bearing unicompartmental knee replacement designed for the lateral compartment

“…To date, there are only few published reports on the clinical outcome and survivorship of fixed-bearing lateral UKR with large variability in clinical results and longevity [ 17 , 18 , 29 – 35 ]. The primary objective of this study was to assess the clinical effectiveness of the FLO partial knee replacement in a large cohort of patients.…”

Lateral Knee Osteoarthritis

“…The advantages of this technique lie in the low loss of blood during the operation and a low rate of complications. [37,38] The results of medial and lateral partial arthroplasty are similar. Partial arthroplasty is contraindicated in patients with involvement of other compartments of the knee, presence of instability, inflammatory arthritis, and fixed valgus deformity.…”