NeuFlex and Swanson metacarpophalangeal implants for rheumatoid arthritis: prospective randomized, controlled clinical trial.

PURPOSE: To compare postoperative range of motion (ROM) and function in a randomized prospective trial of Swanson and NeuFlex metacarpophalangeal (MCP) joint implants. METHODS: A total of 33 patients who had rheumatoid arthritis underwent primary MCP arthroplasty of all 4 fingers in 40 hands; 20 received Swanson implants and 20 received NeuFlex implants. Exclusion criteria included diagnosis of other connective tissue disorders and previous MCP joint surgery. All participants followed the same postoperative rehabilitation protocol. The primary outcome measure was active MCP flexion. Secondary outcomes included active MCP extension, arc of motion, ulnar drift, function (Jamar grip strength and Sollerman hand function test), and the Michigan Hand Questionnaire. Patients were assessed preoperatively and 12 months postoperatively. RESULTS: Patients' mean age was 62.5 years (Swanson) and 58.1 years (NeuFlex) (p = .03). A total of 19 of 20 hands (Swanson) and 14 of 20 hands (NeuFlex) were from female patients. Preoperative active ROM was not significantly different. At follow-up, both groups demonstrated increased active extension and arc of motion (p < .001), reduced active flexion and improved ulnar deviation (p < .001), increased mean Sollerman and Michigan Hand Questionnaire domain scores (p < .001), and improved grip strength (p = .03). Active MCP flexion was significantly greater in all 4 digits of hands with NeuFlex implants compared with Swanson implants. The NeuFlex group demonstrated a greater total arc of motion in the little finger. Implant groups were not significantly different by individual digit for active MCP extension, ulnar drift, and composite flexion. Functional outcomes did not differ between groups. Patients with Swanson implants reported higher Michigan Hand Questionnaire scores in the function and aesthetics domains. CONCLUSIONS: Both implant groups obtained satisfactory clinical improvement after MCP reconstruction of the hand. The NeuFlex group demonstrated superior ROM, whereas the Swanson group had better self-reported function and aesthetics, but not objectively measured function. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic I.

Insufficient flexion of the metacarpophalangeal joint of the little finger following Swanson silicone arthroplasty for rheumatoid arthritis.

Twenty-one patients with rheumatoid arthritis who underwent Swanson metacarpophalangeal (MP) arthroplasty from 1994 to 1999 were assessed for active flexion of individual MP joints an average of 59 months (range 27-114 months) postoperative. Published articles of Swanson MP arthroplasty were reviewed. Experienced hand surgeons were surveyed regarding outcomes of metacarpophalangeal arthroplasty. The MP joint of the little finger displayed significantly less flexion than that of the middle and index finger. Seven of eight published studies which present active MP flexion by individual digit demonstrated less flexion in the little finger compared to the index, middle, and ring finger. Half of surgeons surveyed reported that MP range of motion is shifted toward a more extended position, that MP flexion is limited in the ulnar digits, and that an implant that encourages MP flexion would be helpful. Our experience with this cohort, a review of published literature, and a survey of international experts suggest that Swanson arthroplasty frequently results in a range of flexion of the MP joint of the little finger that may be insufficient for its principal functions.