Medial calcar of proximal humeral fracture as landmark in restoration of humeral length in case of hemiarthroplasty

Purpose

Several methods to restore the appropriate length of the humerus in the case of proximal humeral fractures treated by hemiarthroplasty have been previously published. Our study evaluates the possibility of using the medial calcar of humerus for humeral length reconstruction not based on preoperative planning.

Methods

Preparations of 320 dry humeral bones were used for the purpose of the study. Points of interest were marked on each bone: the most proximal point of the humeral head, the crest of greater tuberosity, diameters of the head, the anatomical and surgical necks. Proximal parts of bones were then scanned from two angles with a digital camera and all measurements were performed on calibrated photographs. We compared accuracy in humeral length reconstruction using insertion of the pectoralis major and the area of medial calcar where usually a fracture develops.

Results

The distance between the top part of the humeral head and the insertion of pectoralis major was 54.1 ± 6.0 mm. The distance between the lateral margin of the anatomical neck and the medial calcar was 51.4 ± 4.3 mm. We compared these data with diameters of the humeral head.

Conclusions

The site of the fracture can be used for the reconstruction of the humeral length with greater accuracy than area of the pectoralis major insertion. We suggest that to obtain the final distance between the lateral margin of the artificial head and medial calcar of the fracture 2–3 mm should be added to the diameter of the head.