Stability of scaphotrapeziotrapezoid novel arthrodesis apparatus / 中国组织工程研究

ABSTRACT

BACKGROUND: Traditional scaphotrapeziotrapezoid limited intercarpal arthrodesis contains Kirschner wire, U-shaped nail, AO/ASIF steel plate and so on. Long-term plaster external fixation was needed following surgery. USA-designed arthrodesis apparatus is mainly suitable for European and people from USA, but not fit for Asian.OBJECTIVE: To simulate scaphotrapeziotrapezoid limited intercarpal arthrodesis, and to test the stability of the novel arthrodesis apparatus developed by the group according to anatomic form of dorsal joint fovea of Chinese scaphotrapeziotrapezoid.DESIGN, TIME AND SETTING: The observational study was performed at the Laboratory of Biomechanics of the Department of Orthopaedics, Nantong University from April 2006 to March 2007.MATERIALS A total of 40 fresh forearm samples of corpses that were not subjected to antiseptic treatment were used for this study. Radiograph verified that these samples did not develop wrist joint affection or abnormal alinement.METHODS: The cadaver models were imitated limited intercarpal instability before scaphotrapeziotrapezoid arthrodesis used circular plate. Then, simulated flexion 50°, extenion 35°, ulnar deviation 30°, radial deviation 10° ultimate activities (50000).CT scan and 3-D reconstruction should be taken before and after motion.MAIN OUTCOME MEASURES: The index of the radial-scapho angle (RSA), radial-scapho distance (RSD), scapho length(SL), trapezium-trapezoid inclination (TTI), trapezium-trapezoid width (TTW) were measured.RESULTS: Prior to motion RSA, RSD, SL, TTW and TTI were (38.725±2.230) °, (18.988±1.216) mm, (1.686±0.191) cm,(27.360±1.571) mm and (114.975±2.293) °. Following motion RSA, RSD, SL, TTW and TTI were (38.800±2.388) °,(19.215±1.443) mm, (1.683±0.209) cm, (27.718±1.910) mm, (115.300±3.023) °. No significant difference in above-described indexes was determined before and after motion (P > 0.05).CONCLUSION: The novel STT limited intercarpal arthrodesis apparatus shows confidential stability. Thus, wrist joint can do exercises in an early stage at the range of 35 dorsal extension, 50 palmar flexion, 10 radial deviation and 30 ulnar deviation.