[Shape-memory osteosynthesis for trapeziometacarpal joint arthrodesis].

PURPOSE OF THE STUDY: Arthrodesis of the trapeziometacarpal joint is the method of choice in the treatment of degenerative arthritis of this joint. This procedure was indicated most frequently in middle-age patients doing hard manual labor. Methods for achieving a solid fusion of the trapeziometacarpal joint are known and often reported in the literature. Frequently, they are associated with some failure rate, particularly as concerns bone union. Our study presents a simple and effective method verified in cadaver specimens and then currently used at our department.

MATERIAL AND METHODS: The procedure for arthrodesis of the trapeziometacarpal joint was verified fist in fixed wrist and hand specimens at the Institute of Anatomy, 1 st Faculty of Medicine, Charles University in Prague. If the original shape of the basal thumb joint between the trapezium and the metacarpal is maintained, it allows for correct reduction and subsequent arthrodesis in a required position. In patients, surgical treatment included the use of implants, two DePuy shape-memory staples, which facilitate sufficient fragment compression and provide stable fixation. The staples were inserted in pre-drilled and gauged tunnels in the body of the trapezium and in the proximal metaphysis of the fist metacarpal.

RESULTS: Between 2011 and 2014, the procedure was used in 14 patients diagnosed with primary arthritis of the trapeziometacarpal joint. The group comprised nine women and five men, the average age was 52 years and the range was 44 to 69 years. Surgery was most frequently carried out on the dominant upper extremity (85%); there was no bilateral surgery. The average follow-up was 18.3 months (range, 5 to 39 months). Solid fusion was recorded at 7 weeks after surgery in all patients except for the one still treated at the time of this paper submission. All patients were free of pain, ten reported satisfaction with grip strength and hand function, the rest would have preferred improvement in fine motor skills of the thumb. All of them found the cosmetic appearance of the hand satisfactory..

DISCUSSION: The methods generally used for trapeziometacarpal joint arthrodesis are reported to carry some risk of pseudarthrosis development. A lot of modifications have been described, from conventional procedures using AO lag screws or Kirschner wires to up-to-date plate systems involving angle-stable fixation. Total fusion of the trapeziometacarpal joint is disputable in patients with rheumatoid arthritis from the technical point of view as well as the relevance of indication criteria. Some authors consider this procedure a contraindication for patients with rheumatoid arthritis. The use of joint replacement in treating trapeziometacarpal joint arthritis is another complex issue.

CONCLUSIONS: An arthrodesis of the trapeziometacarpal joint based on careful assessment of indication criteria proved to be a simple, effective and low-cost method of stable osteosynthesis that provided good conditions for solid fusion of the trapezium with the base of the fist metacarpal. It allowed for sufficient abduction and opposition of the thumb, thus permitting satisfactory hand grip strength and full involvement in everyday life activities and occupations. It provided stability of the thumb, its painless movement and good cosmetic looks.