Foreign body reaction after modified silicone rubber arthroplasty of the first carpometacarpal joint

Twenty patients who had been treated with a silicone rubber trapezial implant for degenerative changes in the first carpometacarpal joint were evaluated radiologically and clinically. After a mean follow up of 4.5 years, 11 of the 20 required reoperation and removal of the prosthesis for persisting pain and weakness. In all hands in which the prosthesis remained radiographs showed bone resorption or carpal bone cysts typical of silicone particle synovitis. In the light of these results we now do not recommend this procedure for the treatment of arthritis of the first carpometacarpal joint

Intraneural edema following exposure to vibration

Peripheral neuropathy represents a well-known complication from long-term exposure to vibration. In the present study an experimental model is presented with the purpose of analyzing the formation of intraneural edema following vibration exposure. Vibration (82 Hz, peak-to-peak amplitude 0.21 mm) was induced in the hind limb of rats by the use of vibrating electric motors during 4 h/d for 5 d. Tracer techniques (with albumin Evans blue and horseradish peroxidase) were used to study the permeability of intraneural microvessels after the vibration exposure on day 5. It was found that the vibration trauma in this model induced epineurial edema in the sciatic nerve. It is hypothesized that the formation of intraneural edema may be an important pathophysiological factor in the occurrence of vibration-induced neuropathy