[Early results of NeuFlex silastic implant in MCP arthroplasty]

For the reconstruction of destroyed metacarpophalangeal (MP) joints in rheumatoid arthritis, the Swanson silicon spacer is still the golden standard. However, long-term follow-up reveals an increasing number of complications, particularly mechanical failure. In order to deal with these problems a number of new, biomechanically different silicone implants have been designed. Among these, the NeuFlex prosthesis has a preflexed hinge of 30 degrees in relation to the shaft axis, a more palmar lying center of rotation and a rectangular hinge with a collarlike platform against the bony surfaces. In a prospective study, the early results of the first thirteen patients operated with the NeuFlex arthroplasty are reported. All patients suffered from rheumatoid arthritis with destruction of the MP joints. The mean follow-up was 12.3 months. A total of 37 joints were replaced. All patients were female with an average age of 56 years. Postoperative reduction of pain, measured on a visual analog scale with the maximum of 10 (VAS), decreased from 6.6 to 0.7 (p < 0.001). Jamar grip strength improved from 4.2 kg preoperatively to 9.9 kg postoperatively (p < 0.005). Range of motion improved from 37 degrees to 57 degrees (p < 0.0001) as a result of a reduction in active extension deficit which reduced from 35 degrees to 15 degrees postoperatively. Ulnar drift was reduced from 20.2 degrees to 3.4 degrees at follow-up (p < 0.005). Radiological evaluation showed no implant failure, no subsidence, and no signs of inflammatory reaction. Overall the NeuFlex silicone implants show encouraging early results which must be confirmed in the long term.