M. Rittmeister et al., Metacarpophalangeal joint arthroplasty in rheumatoid arthritis: results ofSwanson implants and digital joint operative arthroplasty, ARCH ORTHOP, 119(3-4), 1999, pp. 190-194
We discuss 69 metacarpophalangeal (MP) implant arthroplasties performed in
30 patients with rheumatoid arthritis. The follow-up averaged 5 years. We s
tudied 19 finger joint prostheses by Condamine, digital joint operative art
hroplasty (stabilized version; DJOA) and 50 flexible silicone Swanson impla
nts. We used a new comprehensive scoring system to evaluate the MP alloarth
roplasties. Such a scoring system incorporates clinical and radiological da
ta. The outcome following MP joint replacement with DJOA was never evaluate
d as 'good'; in 11 joints the result was 'fair', and in 8 joints, 'poor'. A
s regards MP arthroplasty with Swanson implants, the results were evaluated
as 'good' in 40 joints, as 'fair' in 10 joints, and in none as 'poor'. In
our series, DJOA did not provide stability in arthritic MP joints. In all j
oints replaced with DJOA, dislocation of the articulating surfaces and sign
s of loosening were present. We regard three factors as being the main caus
es contributing to the poor outcome of DJOA when used as MP replacements. F
irstly, the proximal prosthetic component is poorly matched to the anatomic
al shape of the metacarpal bone (conisation of the bone). Secondly, adequat
e coaptation cannot be achieved with this prosthetic design, even in the pr
esence of extensive soft-tissue reconstruction. Thirdly, the use of polyeth
ylene in MP joint replacements is questionable. In contrast, the silicone S
wanson implants in our series provided superior results when used as MP imp
lants in the rheumatoid hand.