[Recent post-traumatic luxation of the trapeziometacarpal joint. Apropos of 8 cases]

Eight cases of acute traumatic dislocation of the trapezio-metacarpal joint treated by percutaneous pinning without ligamentoplasty are reported in order to evaluate this method.

Eight patients, two women aged 32 to 38 and six men aged 17 to 43, were treated for acute traumatic dislocation of the trapezio-metacarpal joint between 1986 and 1993. The injury happened in a road traffic accident in five cases, during a fight in one case, and in a fall in two cases. The mechanism of injury could be determined only twice as a longitudinal force applied on the first metacarpal bone with the trapeziometacarpal joint in flexion. The dominant hand was injured in five cases. The metacarpal base was always dislocated dorsally. Closed reduction was always easy but remained unstable. On the initial radiographs, one patient had a small fragment avulsed from the volar aspect of the metacarpal base, another had a small osteochondral fragment avulsed from the joint surfaces and two patients presented asymptomatic degenerative changes with osteophytes.

All patients were treated on the day of injury by reduction and stabilization by one (in four cases) or two (in four cases) percutaneous Kirchner wires followed by a scaphoid-type cast for six weeks. In only one case an arthrotomy was performed to remove a small osteochondral fragment lodged in the joint, and showed a disruption of the dorsal ligament. All patients were followed-up until the tenth postoperative week, and five of them were reviewed for this study between eight and seventy-eight months (mean 27.5 months) after injury. Enquiries were made about return to work, pain, stability, and range of motion, keypinch and grasp compared with the uninjured side. The joint was examined radiographically with particular attention to the presence of subluxation and degenerative changes.

One patient with a dislocation of the five carpometacarpal joints had reflex algodystrophy; she was not seen for review. Five patients had a completely satisfactory early result at ten week's follow-up examination that maintained at late review for this study. There were no symptoms, no subluxations on the radiographs, and the patients had returned to work between ten to sixteen weeks (mean 11 weeks) post injury. The two patients with degenerative changes on the initial radiographs had early unsatisfactory results with early dorsal subluxation, loss of strength of 30 per cent, but no limitation of joint motion and pain in one case.

Acute traumatic dislocation of the trapezio-metacarpal joint is an uncommon injury; it may be associated with a small fragment of bone avulsed from the volar aspect of the metacarpal base or from the articular surfaces. Péquignot and coll. in 1988, and Fontes in 1992 recommended opened reduction and ligamentous reconstruction in acute injuries. Our experience indicates that closed reduction followed by stabilization by percutaneous pinning gives satisfactory results. An arthrotomy may be necessary when an osteochondral fragment avulsed causes incoercibility.

Closed reduction followed by stabilization by percutaneous pinning gives good results in the treatment of acute traumatic dislocation of the trapezio-metacarpal joint. It finds its limits with patients with degenerative changes on the initial radiographs, and in this case ligamentous reconstruction, arthrodesis or arthroplasty might be advocated.