THE ANATOMIC FEATURES OF PROXIMAL RADIUS AND THEIR IMPLICATION FOR OSTEOSYNTHESIS WITH PLATE

Abstract

Purpose: Treatment of radial head fractures of Mason Type II and III involving the neck of the radius is still controversial, especially in the presence of comminution. ORIF often gives unsatisfactory results because of the difficulty in restoring the head-neck off-set and the radial head inclination relative to its neck. In these cases radial head replacement may be indicated ; however, there are no long-term studies on complications and survival of the implant. Recently precontoured plates for the proximal radius has been introduced but no trials have determined whether they are able to restore the normal anatomy of the radius. The latter is still partially unknown because no studies have analyzed the morphology of posterolateral aspect of radial head and neck (“safe zone”). Our study was aimed at:

1. determining the possible presence of anatomical variations of the safe-zone and

2. analyzing the anatomical congruence of precontoured plates to this zone.

Material and Methods: Measurements, performed on 44 cadaver dry radii of adults, included: length of the radius, diameters and height of the radial head, and height and diameter of the neck of the radius. The radius of bending of the safe zone was also calculated.

Results: The morphological evaluation of the “safe zone” of the radius revealed 3 different morphological types of this zone:

• (flat) (25 %),

• (slightly concave) (63,6 %) and

• (markedly concave) (11,4 %),

Adherence of a precoundered plate (Acumed) to the bone surface of the safe zone was performed independently by three of us, and the gap between plate and bone was measured. Plate adaptability was good in Type B, scarce in Type C and absent in Type A.

Conclusion: In conclusion, we identified 3 different morphologies of the safe zone, not previously described, and we found that the precountered plates now available can ensure a good restoration of anatomy only in the half of the human radii.