PubMed · 649201
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C H Wynn-Jones. 1978. A simple external fixation method using wire and bone cement.. https://doi.org/10.1016/s0020-1383(77)80057-0
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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.
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.
This experimental study was conducted to determine the best scaphoid position, measured as the radioscaphoid (RS) angle for optimum wrist motion after scapho-trapezio-trapezoid (STT) and scaphocapitate (SC) fusion and to assess the implications of radial styloidectomy on motion after STT fusion. STT and SC fusions were simulated in six fresh cadaver hands with the scaphoid in horizontal, neutral, and vertical positions with respect to the long axis of the radius seen on lateral x-rays. RS angle and wrist motion were measured on x-ray films before and after each simulated arthrodesis. Radial deviation and wrist extension increased as the RS angle increased (i.e., increased as the scaphoid became more nearly vertical). Ulnar deviation and flexion decreased as the scaphoid became more nearly horizontal. We found no statistically significant differences in RS angle between SST and SC fusions with respect to ulnar deviation, flexion, or extension. However, radial deviation was more sensitive to RS angle after STT fusion than after SC fusion, but the differences were not statistically significant. The ideal radioscaphoid angle (range) for maximal wrist motion when STT fusion is performed is 41 to 60 degrees; when SC fusion is performed, it is 30 to 57 degrees. Motion is not improved by radial styloidectomy after simulated STT fusion.