Determination of radiographic guidelines for percutaneous fixation of proximal humerus fractures using a cadaveric model

The humeral heads of whole body cadaveric shoulders underwent fluoroscopic evaluation with the head divided into three zones on both anteroposterior (AP) and axillary views creating nine zones. Five AP and three axillary fluoroscopic images in different rotational positions were assessed for pin penetration. All images were evaluated for pin penetration and the AP view was evaluated for lesser tuberosity location. Pins placed appropriately below the subchondral bone did not appear to penetrate the joint on any fluoroscopic image. Pins placed 2 mm beyond the articular surface were appropriately viewed exiting the head on most views (64%) but falsely appeared within the head on several others (36%). Pins perforating the posterior head were problematic for accurate detection on AP views (missed in 87%), but this was avoided by externally rotating the humerus to 60°. Articular penetration cannot always be appreciated radiographically and special efforts are necessary to avoid this problem including the use of various rotational views as well as the use of appropriate orientation such as the lesser tuberosity position.