A Simplified Method for Determining the Safe Zone in Proximal Radial Plate Fixation

The radial head and neck feature a unique anatomical structure, whereby the application of a plate in certain areas can lead to impingement, subsequently restricting the forearm rotation. Various techniques have been suggested to identify the appropriate region for plate fixation. We propose an alternative method to locate a safe zone for plate placement and conduct a comparative analysis with previously established methods.

The study included 30 embalmed cadavers. All specimens demonstrated a full passive range of forearm rotation. A plate was positioned on the most anterior aspect of the radial head/neck with the forearm in full pronation (anteroposterior position) and on the most posterior aspect with the forearm in full supination (P-S position). We assessed the range of motion to identify proximal radioulnar joint impingement and compared the plate's positioning to the safe zone described by Caputo and Smith.

All specimens maintained a full passive range of motion following plate fixation in all positions. The plate placement fell within the boundaries of Caputo's radial styloid direction and Smith's Lister's tubercle direction. The average plating zone measured 94°.

Positioning the plate at the most anterior aspect during forearm pronation or at the most posterior aspect during forearm supination may serve as an alternative method for identifying a safe fixation zone that avoids proximal radioulnar joint impingement. Using this technique, all specimens demonstrated a full passive range of motion after plate placement, and the plates were positioned within the standard safe zone of the proximal radius.