Influence of the scaphotrapeziotrapezoid joint on the results of total trapeziometacarpal prostheses.

INTRODUCTION

Scaphotrapeziotrapezoid (STT) joint osteoarthritis may influence the outcome after trapeziometacarpal prosthesis (TMP) implantation. The literature regarding its clinical and radiological assessment is unclear. The aim of our study was to determine by means of a pre- and post-intervention CT study whether the degree of STT involvement influences the clinical-functional or radiological results after TMP implantation, and to establish whether or not STT osteoarthritis could be a contraindication for the use of these implants.

METHODS

Prospective study of 60patients with trapeziometacarpal osteoarthritis grade III-IV operated between 2017 and 2022. The Van Cappelle functional test, pain, strength and mobility were evaluated. Simple radiology study and CT scan evaluating STT pre and post-surgery. The results were analyzed in relation to the joint space. Recording of complications and statistics.

RESULTS

A total of 50 patients completed the study, mean age 59years, mean follow-up 56months, 36Isis® and 14Touch® were implanted. Significant improvement was observed in all variables. The STT joint space didn't change after the intervention, and no statistical association was found between the STT joint space and the different clinical-functional variables. Three cases (6%) suffered STT pain and none required surgical revision. No infections, dislocations or loosening. Four De Quervain's tenosynovitis and two perimplant ossifications were observed. Survival of the implants was 100%.

CONCLUSIONS

The use of TMP in patients with trapeziometacarpal osteoarthritis has excellent short and medium-term results, regardless of STT involvement, so it should not be a contraindication for osteoarthritis at this level.