Artikel
Three dimentional kinematic analysis of scapholunate joint during axial-loaded extended wrist position
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Autoren
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Junya Hojo
- Heisei Memorial Hospital, Kashihara, Japan
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Shohei Omokawa
- Nara Medical University, Department of Hand Surgery, Kashihara, Japan
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Hiroshi Ono
- Nishi Nara Central Hospital, Hand Center, Nara, Japan
| Veröffentlicht: | 6. Februar 2020 |
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Gliederung
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Objectives/Interrogation: Wrist injuries are most frequently caused by falls on an outstretched hand, resulting in bone fracture or ligament injury when the wrist joint is loaded in an extended position. We hypothesized that kinematic change would occur in the scapholunate joint when the wrist joint is loaded in an extended and pronated position. The purpose of this study was to investigate changes in the lengths of simulated scapholunate ligaments during wrist extension with axial loading and to clarify whether loading changes scapholunate joint kinematics.
Methods: The dominant arms of 9 volunteers with healthy wrists were studied. We mounted a compression device onto the elbows in an inverted position. A 0-kg and 7-kg load each was applied during low-dose radiation CT imaging and a bone model was produced. We marked the insertion sites for the 3 scapholunate ligaments stabilizing the scapholunate joint: proximal scapholunate ligament(P-SL), volar scapholunate ligament(V-SL), dorsal scapholunate ligament(D-SL). Each ligament was virtualized and the length of each simulated ligament was measured.
Results and Conclusions: The length of P-SL was 4.82mm at 0kg and 4.85mm at 7kg. The length of V-SL was 3.66mm at 0kg, and 3.79mm at 7kg. The Length of P-SL and V-SL increased under the loaded condition compared with the unloaded condition but this difference was not statistically significant. The length of D-SL was 4.05mm at 0kg, 3.94mm at 7kg. The length of D-SL decreased significantly under the loaded condition compared with the unloaded condition.
The dorsal SL ligament is an important ligament stabilizing the scaphoid bone and lunate bone, but it was thought that the compression force is generated on the dorsal side by the load and the length of the D-SL is shortened. Although not significant, the V-SL extends, there is a possibility that the ligament were stretched during axial loading. This results may support that there may be a progressive tearing of the SL ligaments from palmar to dorsal, eventually leading to a complete scapholunate dissociation.
