Abstract
Intramedullary lengthening, in cases of extensive humeral shortening, offers the advantages of preventing external-fixator-associated problems. The humeral cavity, as the main parameter in nailing, however, has been neglected in recent literature. It was hypothesized that available implants might be too large and therefore increase the risk of intraoperative fractures. The aim of this cross-sectional study was to describe the humeral canal and how it might affect the choice of implant and the surgical approach. Thirty humeri (15 female, 15 male) from clinical patients and anatomical specimens were studied. Specifically, the medullary cavity width (MCW), cortical thickness (CoT), and the course of the medullary canal were examined. The smallest MCW diameters were found at the distal third of the humeral shaft with mean diameters of 10.15 ± 1.96 mm. CoTs of female humeri were significantly smaller than those of male humeri (p < 0.001). The mean angles of the pro- and recurvatum were 4.01 ± 1.68° and 10.03 ± 2.25°, and the mean valgus bending was 3.37 ± 1.58°. Before implanting a straight lengthening nail into a doubly curved humerus, X-rays and, in selected cases, CT-scans should be performed. The unique size and course of the humeral canal favors an antegrade approach in cases of intramedullary lengthening.
Highlights
Limb lengthening goes back to the work of Ilizarov, who initially introduced an external apparatus for bone fragment fixation and lengthening in the early 1950s [1]
The purpose of this study was to describe the anatomy of the humeral canal and its clinical relevance in fitting a straight nail down the doubly curved humeral bone
While safety spots for intramedullary nailing and locking screws are well-known in clinical practice, the shape of the humeral cavity has been neglected as an important parameter in preoperative planning [17,18]
Summary
Limb lengthening goes back to the work of Ilizarov, who initially introduced an external apparatus for bone fragment fixation and lengthening in the early 1950s [1]. Carries the risk of pin infection, perioperative nerve and soft tissue irritation, and discomfort during treatment [2]. In 2015, an expert review depicted intramedullary nailing and lengthening for the humerus [3]. Disability, and functionality scores showed improvements with these interventions [4,5,6,7]. A similar consolidation index to external lengthening was seen [8]. The main advantage of intramedullary implants is that they ensure Range-of-Motion (ROM) during the lengthening phase at pre-surgery levels [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
