Disillusioning midterm results after UNI 2 total wrist arthroplasty in RA Patients

Total wrist arthroplasty attempts to produce a stable, pain free joint. Avoidance of arthrodesis is a strong impetus. Early results of the Universal total wrist arthroplasty KMIy in wrist arthritis were at least as encouraging as were reports with other implants. The five to ten year outcomes showed a 45% revision rate with arthrodesis rate below 10%. Our question was wether results withstand over time.

Material and method

Between 2002 and 2012, 12 rheumatoid patients all but one female had cementless UNI 2 total wrist arthroplasty - the only implant used by a single surgeon - on 14 wrists, average age of 68, 55 years (range 37–84 y.). Indication was panarthritis of the carpus with Simmen Grade I and II without major bone loss intact tendons without active synovitis or infection. No patient was dependent on walking aids. At follow-up average 6.9 years the only question was on the status of the implant whether radiological and mechanical stable or not. Two patients were lost to follow-up due to death for other medical reasons.

Results

During the follow-up 9 wrists or 75% of the surviving got clinically symptomatic with increasing pain, local swelling and radiovolar drift of the carpus. There was in any instance polyethylene wear accentuated on the radius, synovitis and secondary carpal tunnel syndrome. After an average of 5 years revision rate rose markedly. Radiologic and mechanical loosening of the carpal component was seen 7 times. Surgery - twice there was only the change of the polyethylene component necessary. Three times the carpal component had to be changed in combination with cancellous bone adjunct. Finally, 4 revisions ended in arthrodesis, two of those in first revision. At present, two more patients with three implants are due to reoperation. Thus, arthroplasty showed complication in 75% and mobility was lost in 33% of the surviving.

Discussion

Early results of the universal total wrist arthroplasty KMIy in rheumatoid arthritis were encouraging. Midterm results show an array of problems focussing on the carpal component. These studies generally sum up degenerative, posttraumatic and rheumatoid arthritis cases. To our knowledge ours is the only focusing on RA patients only.

The majority of publications delude oneself to believe in total wrist arthroplasty in this category of patients. The authors own experience is much more deceiving. In our department total wrist arthroplasty in rheumatoid patients is no longer the treatment of choice.