Silicone rubber implants for arthrosis of the scaphotrapezial trapezoidal joint.

Degenerative changes of the scaphotrapezial trapezoidal (ST) joint commonly cause pain and weakness. These patients do not respond to conservative treatment, and for several years effort has been made to find an easy way to relieve symptoms. In a previous report a silicone interposition arthroplasty was described and considered to be a useful method. However, the durability of the elastomer was insufficient, and implant fractures and migration of fragments occurred. Since then the procedure has been modified, and high performance Silastic has been used for interposition. Ten patients have been reviewed, with a follow-up from 6 to 36 months (average 15 months). All patients have had lasting relief from pain and consider they have full hand function, without stiffness or limited thumb or wrist motion. Roentgenographic reviews have neither revealed deterioration nor dislocation or migration of the implant. Untoward bone reactions have not been observed. Implant hemiarthroplasty is indicated only when the degenerative changes are solely confined to the ST joint.