Long-term outcomes of Kudo type-5 unlinked surface-replacing total elbow arthroplasty for rheumatoid arthritis: a 15-year average follow-up study.

Background: Total elbow arthroplasty (TEA) has been used for various conditions including rheumatoid arthritis (RA). While the Kudo TEA has been associated with favorable short-term outcomes, there is limited information on the longer term outcomes of this device. The aim of this study was to investigate the average 15-year outcome of Kudo type-5 TEA in patients with RA.

Methods: For this retrospective cohort study, we reviewed 29 elbows in 28 patients (Larsen grade III, n = 8; IV, n = 19; V, n = 2) with RA who underwent Kudo type-5 TEA between 1999 and 2010. The patients were followed up for a mean of 15 (range: 10-21) years. We investigated the survival with setting revision/removal as the endpoints. The risk factors for revision/loosening were assessed.

Results: There was a significant improvement in elbow flexion after Kudo TEA. Preoperative and postoperative Mayo Elbow Performance Score improved significantly from 60.3 to 94.7. Complications included intraoperative medial humeral epicondyle fracture (n = 2), postoperative dislocations (n = 4), deep infections (n = 1), and persistent ulnar nerve neuropathy (n = 1). Aseptic loosening was observed in 7 elbows (24.1%; humerus, n = 3; ulna, n = 3; both sides, n = 1). The causes of the 5 revisions were postoperative dislocation (n = 1), deep infection (n = 1), aseptic loosening of the humerus (n = 2), and aseptic loosening of the ulna (n = 1). All 5 elbows underwent revision of the ulnar component (n = 2) or the linked TEA (n = 3). The survival rate was 81% at 15 years after surgery with setting revision/removal as the endpoints. A deviation of ulnar component insertion angle of over 5° in any plane was associated with more revision compared to those with accurately placed implants.

Conclusion: The Kudo type-5 elbow showed good results for up to 15 years of follow-up. However, excessive deviation of insertion angle of the ulnar component (over 5°) was associated with more revision. Due to the small sample size, robust statistical analysis of risk factors for postoperative complications or revision could not be performed, and further research is warranted to resolve this limitation.