Volar and dorsal mid-shaft forearm plating using DCP and LC-DCP: interference with the interosseous membrane and forearm-kinematics.

PURPOSE

To clarify if dorsal plate osteosynthesis of the forearm shaft is associated with impingement of the interosseous membrane (IOM) and if rotational kinematics of the forearm are influenced.

BACKGROUND

Forearm fractures are treated by separate incisions. Osteosynthesis via one approach in proximal forearm fractures was associated with higher rates of synostosis. It has been claimed that this is due to IOM impingement.

MATERIALS AND METHODS

16 forearms of fresh frozen cadavers were dissected until only radius, ulna and the IOM remained. To preserve physiological forearm rotation, the elbow joint, the distal radio-ulnar joint and the carpus remained intact. In group 1, LC-DC and DC plates were placed on the flexor aspect of the respective bone. In group 2, the plates were placed ulnodorsal and radiodorsal. The distance between the plates and their effect on the IOM were investigated in a newly designed forearm simulator and measured in 30 degrees, 60 degrees and 90 degrees of pronation and supination respectively.

RESULTS

The IOM was affected in neither group. There was no interference of the kinematics in group 1. In group 2, plate contact appeared in one pair in both types of plate. The plates were significantly closer in all positions in group 2. There was no difference between the various plates in the two groups.

CONCLUSION

Dorsal plate osteosynthesis of the forearm shaft is not associated with an impingement of the IOM. Malpositioning of the plates is more likely to be of more effect in dorsal plate positioning and leads to interference with the kinematics.