gms | German Medical Science

Objectives: To investigate whether biologicals affect the risk of aseptic loosening after total hip/knee arthroplasty (THA/TKA) in patients with rheumatoid arthritis (RA) compared with conventional disease modifying antirheumatic drugs (DMARDs).

Methods: We retrospectively identified all patients suffering from RA who underwent THA/TKA at our academic centre between 2002 and 2015 and linked them with an existing prospective observational RA database at our institution. All participants fulfilled the 1987 ACR, or more recently, the 2010 ACR/EULAR classification criteria for RA. Based on their antirheumatic medication, patients were divided into two groups, patient under therapy with traditional DMARDs and patients under therapy with biologicals. The risk of aseptic loosening was estimated using radiographic signs of component loosening (RCL). Logistic regression, with location of TJA as a covariate was used to compare RCL rates in patients under therapy with traditional DMARDs versus patients under therapy with biologicals. Chi-square test was employed to compare RCL rates in the TKA group and in the THA group. Furthermore, we assessed the time until RCL in both groups using the Kaplan Meier method and applied the Log-Rank test to compare survival distributions.

Results and Conclusion: We identified 155 patients (120 female, 35 male), who met the inclusion criteria and were retrospectively enrolled in the study. TKA was performed in 103 cases and THA in 52 cases. Mean age at implantation was 59 ± 13 years. Mean follow-up time was 69 ± 43 months. Overall, 39 of 103 (37.9 %) patients under therapy with traditional DMARDs showed signs of RCL, compared to 9 of 52 (17.3 %) patients under therapy with biologicals (p = 0.009). This difference in RCL rates between DMARDs and biologicals was more pronounced in the TKA group with 25 of 71 (35%) patients under DMARDS compared with 3 of 32 (9%) of patients under biologicals showing signs of RCL (p = 0.006). In the THA group, 14 of 32 (43.7%) patients under DMARDS and 6 of 20 (30%) patients under biologicals showed signs of RCL (p = 0.32). Sixteen patients underwent revision surgery during follow-up. Aseptic loosening was the most common reason with seven patients in the DMARD group versus two in the biologicals group.

Total joint replacement in RA patients is associated with a high rate of RCL as well as revisions for aseptic loosening. Biologicals may reduce the incidence of aseptic loosening after THA/TKA in patients with rheumatoid arthritis compared with traditional DMARDs.