The distal part of the interosseous membrane (IM) may contribute to ankle joint stability and therefore partly explain the results of a study that reported no difference in outcome in patients with low Weber C fractures treated with or without a syndesmotic screw. The aim of the current study was to compare the strength of the IM to the interosseous ligament (IL).
Six paired cadaveric lower extremities were stripped, leaving only the IM and the IL intact. The tibia was fixed and a load was applied via a steel plate to the lateral surface of the fibula to displace it with respect to the tibia along the line of the fibers of the IM and IL. In group one the interosseous ligament was sectioned and the interosseous membrane was mechanically tested until failure. In group two, the interosseous membrane was sectioned and the interosseous ligament was tested.
The interosseous membrane was 30% stronger than the interosseous ligament (1040 ± 183 N versus 798 ± 322 N, respectively; mean ± SD).
The current biomechanical study found that the IM was 30% stronger than the IL. The interosseous membrane has considerable strength and may play a role in ankle stability.
