[Errors and complications in compression-distraction osteosynthesis].

Anatomic characteristics of the lunate, the pisiform and the capitate were compared in order to support the use of a pisiform transplant or the intercarpal fusion by Graner in advanced stages of Kienböck's disease. Fifty lunate and pisiform bone pairs and 20 wrist specimens served for morphological and functional investigations. In view of the present results, the pisiform, after a rotation of 90 degrees, should be implanted in the lunate box with its longitudinal diameter oriented to the dorsopalmar plane. Despite the small pisiform volume, maintainance of carpal height is assured by its relatively large dorsopalmar diameter. The rotated position permits use of existing soft tissue structures and improves the conditions of force transmission. Measurements comparing the radii of curvature of the original lunate and the substitute pisiform surfaces show a good correspondence proximally and a reduction of the articular congruity distally, due to the flatness of the pisiform surface. The palmar convexity of the pisiform adapts better to the distal radius facet than the capitate head, which replaces the lunate in Graner's surgical procedure.

Arthrodesis↗

PubMed1992

Distribution of pressures and forces on the wrist after simulated intercarpal fusion and Kienböck's disease.

Limited intercarpal fusion has been recommended for the treatment of Kienböck's disease. The effects of a simulated scapho-trapezio-trapezoid (STT) fusion and simulated Kienböck's disease on the biomechanics of the radio-ulno-carpal joint were investigated. The percent force, the centroid of the force, and the percent contact area in each fossa were determined. It was found that a STT fusion with the scaphoid in a neutral or extended position unloads the lunate fossa. STT fusion in flexion does not affect lunate load. It is concluded from this biomechanical experiment that STT fusion with the scaphoid in a neutral or extended position unloads the radiolunate joint regardless of the condition of the lunate. This load is shifted to the radioscaphoid articulation.

Arthrodesis↗

PubMed1992

A comparison of scaphoid-trapezium-trapezoid fusion and four-bone tendon weave for scapholunate dissociation.

The contact characteristics of the radiocarpal joint (area, pressure, and ratios of scapholunate area, pressure and force transmitted) were determined with the use of pressure-sensitive film in seven normal wrists after ligament sectioning to create scapholunate instability, with reconstruction involving a scaphoid-trapezium-trapezoid fusion, and with reconstruction involving a four-bone tendon weave procedure. The results demonstrated that the scaphoid-trapezium-trapezoid fusion significantly altered the contact characteristics of the wrist, transferring load, pressure, and area to the radioscaphoid joint, thereby unloading the lunate. In contrast, the tendon weave reconstruction produced characteristics similar to those of the normal joint.

Arthrodesis↗