The trapeziometacarpal joint is often affected by arthritis and treated by surgical methods. The significant forces to which this joint is subjected challenge even the most sturdy prosthetic materials. Short-term complications of arthroplasty are caused by inadequate bony resection and instability. Serious long-term problems results from implant wear and the host tissues' response to the implant. Although silicone elastomer prostheses are generally well tolerated, wear-induced microparticles (15 micron or less) incite an intense inflammatory and destructive synovial response. This "silicone synovitis" typically presents more than two years after arthroplasty and is characterized by pain, swelling, and lytic lesions visible on roentgenogram. The silicone microparticles are generated by cyclic physiologic bearing, shear, and compression forces for which these implants have not been tested. The destructive synovitis is arrested by synovectomy, implant removal, and curettage of the lytic defects. Functional salvage requires conversion to resection arthroplasty or arthrodesis. Patients with silicone implant arthroplasty must be followed indefinitely, at frequent intervals, by clinical examination and roentgenograms. Overall, however, experience indicates that resection arthroplasty is the most predictable and functional procedure for the nonrheumatoid basal thumb joint.