抄録
Objective: To compare the clinical outcome of the Swanson versus the AVANTA silastic implant arthroplasty procedures of the metacarpophalangeal (MCP) joints for patients with rheumatoid arthritis of the hands.
Methods: A total of 48 Swanson and 70 AVANTA implants were inserted into 38 hands of 34 patients (1 male, 33 female). The mean age of the patients at surgery was 61.9±4.8 years in the Swanson group and 61.0±6.2 years in the AVANTA group, respectively. The average follow-up period was 60.7±20.5 and 21.3±9.1 months in the Swanson and the AVANTA groups, respectively. Pre- and postoperative clinical evaluations included active MCP extension and flexion, grip strength, pinch ability, ulnar deviation, osteolytic or sclerotic changes demonstrated by radiography, and overall hand function as assessed by use of the HAQ, Hand20, and DASH scoring systems. Statistical analyses were performed using the Mann-Whitney U test.
Results: The mean postoperative active extension was −13.3°±16.2° in the Swanson group, and −10.7°±10.2° in the AVANTA group (p = 0.72). Flexion was 58.6°±19.8° in the Swanson group, and 59.3°±21.5° in the AVANTA group (p = 0.78). According to the Parkkila criteria, the Grade I and more radiographic osteolysis was seen in the Swanson group (71.9%) as compared to the AVANTA group (62.9%), respectively. The functional scores at the final follow-up were 1.4±0.7 and 1.2±0.8 (p = 0.48) for the HAQ-DI, 57.8±23.1 and 44.5±25.1 (p = 0.19) for the Hand20, and 54.9±21.6 and 41.8±21.6 (p = 0.12) for the DASH disability score in the Swanson group and the AVANTA group, respectively. There were three implant fractures in the Swanson group. No patients had revision surgery during the follow-up period.
Conclusion: Although the AVANTA group was more inclined to obtain a greater range of motion and better functional outcome compared to the Swanson group, there was no statistically significant difference between the two groups. The Swanson group may be associated with a higher implant failure rate due to the silastic mechanical property of the prosthesis, which was identified due to a longer period of follow-up compared to the AVANTA group.
