Have the radiographic characteristics of total knee arthroplasty recipients in rheumatoid arthritis changed after the induction of biologic disease modifying antirheumatic drugs?

Objectives: Whether the characteristics of patients with rheumatoid arthritis (RA) undergoing total knee arthroplasty (TKA) have changed in the era of biologic disease-modifying antirheumatic drugs (bDMARDs) is unclear. We compared the radiographic findings of the knees in TKA recipients with RA before and after the introduction of bDMARDs.

Methods: Consecutive patients who underwent primary TKA between 1999 and 2002 (115 knees; 79 patients, group A) and between 2013 and 2017 (117 knees; 95 patients, group B) were retrospectively evaluated. Clinical data, including disease duration, medication, C-reactive protein, erythrocyte sedimentation rate, and rheumatoid factor, were collected. The Larsen classification, joint space narrowing (JSN), bone erosion, and geode and osteophyte formation were evaluated on preoperative radiographs.

Results: Osteophyte formation was significantly increased, and bone erosion and geode formation were significantly decreased in group B. In addition, medial-dominant JSN was significantly increased, and bicompartmental JSN was significantly decreased in group B. Medial-dominant JSN was positively and bone erosion was negatively associated with osteophyte formation.

Conclusions: Following the introduction of bDMARDs, typical radiographic findings of rheumatoid knees have decreased, and secondary osteoarthritis-like changes, characterized by osteophyte formation and medial-dominant JSN, have increased in the knees of TKA recipients.