Flexible implant resection arthroplasty of the proximal interphalangeal joint in patients with systemic inflammatory arthritis

Forty proximal interphalangeal joint silicone elastomer flexible implant arthroplasties in 19 patients with systemic inflammatory arthritis were reviewed. The follow-up period averaged 94 months. Before surgery, the average arc of motion was 26 degrees for the 20 digits with boutonniere deformities and 23 degrees for the 16 digits with swan-neck deformities. Eight digits had moderate (grade 2) pain, and four digits had severe (grade 3) pain. After surgery, the deformity was completely corrected in six digits. Digits with a preoperative boutonniere deformity (20 digits) achieved the same (26 degrees) arc of motion after surgery, whereas those with a preoperative swan-neck deformity (16 digits) actually lost 18 degrees. Six digits had moderate pain and one digit had severe pain at the final follow-up evaluation. Thirteen digits (7 patients) with a boutonniere deformity before surgery and a concurrent or previous silastic metacarpophalangeal arthroplasty had significantly better results than those without. Overall, there were 12 good, 18 fair, and 10 poor results. Based on this study, flexible silicone implant arthroplasty has a limited role in the treatment of proximal interphalangeal joints affected by systemic inflammatory arthritis. When performing the arthroplasty, attention should be directed first toward correction of the deformity at the metacarpophalangeal joint.