Biological DMARDs May Reduce Aseptic Loosening Following Total Joint Arthroplasties

Biologic disease-modifying antirheumatic drugs (bDMARDs) vs traditional DMARDs are associated with significantly lower rates of radiological signs of component loosening (RCL) following total joint arthroplasties (TJA), among patients with rheumatoid arthritis (RA). This effect is particularly marked following total knee arthroplasty (TKA) vs total hip arthroplasty (THA), according to study findings published in Rheumatology.

Investigators assessed the effects of bDMARDs vs traditional DMARDs on risk for aseptic loosening following TKA or THA among patients with RA.

A retrospective cohort study was conducted including 155 consecutive TJAs performed between 2002 and 2015 at the Medical University of Vienna in Vienna, Austria. As sufficient numbers of patients with revision surgery procedures were lacking, RCL was used to estimate risk for aseptic loosening.

A total of 103 TKAs and 52 THAs were identified among 96 patients.

Patients treated with traditional DMARDs were significantly older at implantation (61±12 years) vs patients treated with bDMARDs (55±2 years; P =.02), though follow-up duration was significantly shorter among patients treated with traditional DMARDs (58±39 months vs 74±7 months; P =.03).

Among the 96 patients, 102 TJAs were treated exclusively with traditional DMARDs and 33 were treated with bDMARDs and traditional DMARDs. Additionally, 20 TJAs originally treated with exclusively traditional DMARDs switched to treatment with bDMARDs with or without traditional DMARDs.

Overall, 31% of patients showed signs of RCL (28 radiolucencies occurring after TKA and 20 after THA). A significantly greater RCL incidence rate was noted following treatment with traditional DMARDs (35%) vs bDMARDs (21%; P =.026).

When investigators assigned patients who had received traditional DMARDs exclusively for at least 1 month to the traditional DMARD group, no significant difference in RCL incidence between the traditional and bDMARD groups was found (P =.704).

However, when assigning patients who had received bDMARDs at least once during follow-up to the bDMARD group, a significant difference in RCL incidence between the traditional and bDMARD groups was found (P =.012).

Study limitations included its retrospective design, underpowered sample size, and potential bias due to differences among patient characteristics and treatments during such an extended study period.

“We conclude that treatment with biological DMARDs seems to reduce the risk of RCL

in RA patients undergoing TJA. This risk reduction seems to be more pronounced after TKA than after THA. Whether this effect of biological DMARDS on the risks of RCL could also be observed in patients undergoing TJA for [osteoarthritis] can only be hypothesized. Additional prospective studies are needed to further investigate these first findings,” the study authors stated.