What factors can reduce the need for repeated revision for humeral loosening in revision total elbow arthroplasty?

ABSTRACT

BACKGROUND: This study aimed to determine the re-revision rate in a cohort of patients who underwent revision total elbow arthroplasty (rTEA) for humeral loosening (HL) and identify factors contributing to re-revision. We hypothesized that proportional increases in the stem and flange lengths would stabilize the bone-implant interface significantly more than a disproportional increase in stem or flange length alone. Additionally, we hypothesized that the indication for the index arthroplasty would impact the need for repeated revision for HL. The secondary objective was to describe the functional outcomes, complications, and presence of radiographic loosening after rTEA. METHODS: We retrospectively reviewed 181 rTEAs performed from 2000-2021. We included 40 rTEAs for HL performed on 40 elbows that either required a subsequent revision for HL (10 rTEAs) or had a minimum of 2 years of clinical or radiographic follow-up. One hundred thirty-one cases were excluded. Patients were grouped based on stem and flange length to determine the re-revision rate. Patients were divided based on re-revision status into the single-revision group and the re-revision group. The stem-to-flange length (S/F) ratio was calculated for each surgical procedure. The mean length of clinical and radiographic follow-up was 71 months (range, 18-221 months and 3-221 months, respectively). RESULTS: Rheumatoid arthritis was statistically significant in predicting re-revision total elbow arthroplasty for HL (P = .024). The overall re-revision rate for HL was 25% at an average of 4.2 years (range, 1-19 years) from the revision procedure. There was a significant increase in stem and flange lengths from the index procedure to revision, on average by 70 ± 47 mm (P < .001) and 28 ± 39 mm (P < .001), respectively. In the cases of re-revision (n = 10), 4 patients underwent an excisional procedure; in the remaining 6 cases, the size of the re-revision implant increased on average by 37 ± 40 mm for the stem and 73 ± 70 mm for the flange (P = .075 and P = .046, respectively). Furthermore, the average flange in these 6 cases was 7 times shorter than the average stem (S/F ratio, 6.7 ± 2.2). This ratio was significantly different from that in cases that were not re-revised (P = .03; S/F ratio, 4.2 ± 2). Mean range of moion was 16° (range, 0°-90°; standard deviation, 20°) extension to 119° (range, 0°-160°; standard deviation, 39°) flexion at final follow-up. Complications included ulnar neuropathy (38%), radial neuropathy (10%), infection (14%), ulnar loosening (14%), and fracture (14%). None of the elbows were considered radiographically loose at final follow-up. CONCLUSION: We show that a primary diagnosis of rheumatoid arthritis and a humeral stem with a relatively short flange relative to the stem length significantly contribute to re-revision of total elbow arthroplasty. The use of an implant where the flange can be extended beyond one-fourth of the stem length may increase implant longevity.