RESUMO
BACKGROUND: The objective of this study is to determine the time-dependent dissipation of extrinsic wrist ligament tension following the application external fixation with axial distraction of the wrist in a cadaveric model. METHODS: Six paired fresh-frozen cadaveric specimens underwent mechanical testing simulating external fixation with 1 arm of each pair osteotomized to simulate a distal radius fracture. The change in tension was then recorded over 24 hours. RESULTS: The rate of stress relaxation decreased with time. The average loss in tension in the control arms and osteotomized arms was 55% and 59%, respectively, over a 24-hour period. There was no statistically significant difference in the stress relaxation behavior between the 2 groups. CONCLUSION: This study further supports the recommendation that comminuted distal radius fractures treated with an external fixator should have Kirschner wire augmentation or other additional means of fixation to help maintain fracture length and alignment. The results of this study call in to question the efficacy of ligamentotaxis alone through external fixation as the sole means of maintaining reduction of displaced, unstable distal radius fractures.
Assuntos
Fixadores Externos , Ligamentos Articulares/fisiopatologia , Estresse Mecânico , Articulação do Punho/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Cadáver , Feminino , Fixação de Fratura , Humanos , Masculino , Pessoa de Meia-Idade , Fraturas do Rádio/fisiopatologia , Fraturas do Rádio/terapiaRESUMO
We present 2 cases of symptomatic nondissociative dorsal intercalated segment instability (CIND-DISI) collapse after trapeziectomy and partial trapezoidectomy for pantrapezial arthritis. Preoperative radiographs showed normal carpal alignment in 1 case and a mild DISI alignment in the other. After surgery both developed increased CIND-DISI and carpal symptoms that differed from their original thumb-base problems. One required carpal realignment and fusion; to date the other has responded to nonsurgical treatment. Such problems may be recognized insufficiently by surgeons and thus may be more common than the current literature suggests.
