The relationship between trapezium union, CMC joint instability and function following pollicisation

Forty-four pollicisations were assessed radiologically for union and stability of the trapezium as well as for stability of the carpometacarpal (CMC) joint. These parameters were compared with conventional clinical measures for strength, range of motion and function. The union rate of the trapezium was 82%. For those with non-union, the relative risk of trapezial instability was 35.0. Patients with trapezial union demonstrated significantly higher grip strength. For those with union, the relative risk of instability at the CMC joint was 1.4. Those with a stable CMC joint demonstrated significantly higher grip strength and functional results. This study suggests that the aim of obtaining union of the new trapezium is of benefit in the procedure of pollicisation