[Treatment of basal joint osteoarthritis by Swanson's trapezium implant arthroplasty].

BACKGROUND: Goal of the present study was the evaluation of clinical and radiological results after treatment of the first carpometacarpal joint by trapezium resection and implantation of a Swanson silicone prosthesis by means of a retrospetive study. However, up to now, only a few long-term data for this surgical technique are available.

METHODS AND PATIENTS: Retrospectively the results of 100 trapezium resections in 72 patients with subsequent joint replacement by a Swanson silicone prosthesis have been followed up over 8.6 years on average. Besides the range of motion, the strengh in grip, tip pinch and key pinch were measured. The quality of pain was determined using a visual analogus pain scale from 1-10. The postoperative subjective satisfaction of patients was recorded as well as the DASH, Mayo, modified Wrist and Krimmer scores. In follow-up X-ray controls, subluxations of the silicone implants as well as bony abnormalities were evaluated.

RESULTS: The postoperative range of motion of the trapeziometacarpal joint in radial abduction was measured with 52° and at palmar abduction with 39°. The average grip strength amounted to 16.5 kg. This represented 80% of the value of the contralateral side. In tip pinch the force value was 3.3 kg, corresponding to 70% of that of the opposite side and in key pinch, it was 3.5 kg, corresponding to 71% of the healthy contralateral side. The DASH score was recorded with 22.5 points. Postoperative pain symptoms on the visual analogue pain scale were recorded at 2.4 points. The majority of the patients were satisfied or very satisfied after the surgical treatment. In X-ray controls, subluxations of the silicone implants could be detected in 54 cases (61.4%) as well as bony abnormalities in 41 cases (46.6%). However, there was no correlation between the radiological findings and patient satisfaction.

CONCLUSION: Trapezium resection and joint replacement with a silicone prosthesis achieves good results. However, the high number of radiographic subluxations of the prothesis and bone abnormalities as a cause of foreign body reactions limits these results. Therefore, despite the good clinical findings, this method will not been conducted any more in our patient population.