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Carpometacarpal dislocation: an aid to diagnosis
1Department of Orthopaedic Surgery, University of Manchester, Hope Hospital, Salford, UK.
Injury
|January 1, 1992
Summary
Diagnosing fifth carpometacarpal dislocation can be challenging. Measuring the angle between the second and fifth metacarpals on true lateral hand radiographs aids detection, with increased angles indicating dislocation or subluxation.
Area of Science:
- Orthopedic surgery
- Radiology
- Hand anatomy
Background:
- Carpometacarpal (CMC) joint dislocations can be difficult to diagnose using standard radiography.
- Overlapping structures in hand radiographs can obscure CMC joint pathology.
Purpose of the Study:
- To evaluate a novel radiographic measurement for diagnosing fifth carpometacarpal dislocation.
- To establish the utility of the carpometacarpal angle in identifying subtle joint instability.
Main Methods:
- Utilized true lateral hand radiographs.
- Measured the angle between the long axes of the second and fifth metacarpal bones.
- Compared measurements in patients with fifth CMC dislocation to a control group.
Main Results:
- Patients with fifth CMC dislocation exhibited an increased carpometacarpal angle (mean 38.5 degrees) compared to controls (mean 9.8 degrees).
- A smaller increase in this angle suggests potential subluxation, requiring further investigation.
Conclusions:
- The carpometacarpal angle measurement on true lateral radiographs is a valuable tool for diagnosing fifth carpometacarpal dislocation.
- This measurement can help identify subtle subluxations that may otherwise be missed, prompting further examination under anesthesia.
