Mechanisms of Injury
Signs and Symptoms
Imaging and Other Diagnostic Studies
Pathoanatomy and Applied Anatomy
Management of Expected Adverse Outcomes and Unexpected Complications
General Adverse Outcomes and Complications
Implant-Specific Adverse Outcomes and Complications
Author’s Preferred Treatment
Summary, Controversies, and Future Directions
My preferred method of operative treatment for diaphyseal humeral fractures is intramedullary nailing (Fig. 36-32). The technique offers the significant advantages of being minimally invasive and respecting the biology while it can accommodate all humeral shaft fractures. Unfortunately, it should be admitted that humeral nailing, in general, has not so far reproduced the results that have established the technique as the “gold standard” treatment for femoral and tibial diaphyseal fractures6,7,16,58,72,143,163,242,284,296,314 possibly because of the complexity of the humeral anatomy and the unique biomechanical characteristics of the arm. In addition, there has been no consensus regarding the fundamental principles of the surgical technique of humeral nailing (e.g., selection of antegrade or retrograde technique, reamed or unreamed nailing, avoidance of complications) or the important technical aspects (such as biomechanical requirements of the humeral nail or nail selection criteria).96
In an effort to improve the efficacy and outcomes of intramedullary nailing of diaphyseal humeral fractures I have proposed that humeral nails must be differentiated in two categories based on their biomechanical properties: “fixed” nails that use screws for interlocking their end opposite to the entry portal and “bio” nails that provide interlocking distal to the insertion site without screws.97 Important considerations that differentiate humeral nailing from the nailing of the femur and tibia and should be taken into account to justify the use of “bio” nailing in the humerus are the following:
All of these parameters enhance the role of “bio” nailing in the management of humeral shaft fractures. However, it is my opinion that both “fixed” and “bio” nails are reliable implants for the humerus but that each type of nail must be used correctly. “Fixed” nails provide optimum stability with the proximal and distal locking screws and, if their design allows, the site of insertion (antegrade or retrograde technique) depends on surgeon preference. The stability provided by “bio” nails depends on their distal locking facility. Stability can be achieved in the Seidel nail if the distal expanding fins engage the endosteum, in the Marchetti-Vincenzi nail if the pins are long enough to diverge and embed into the humeral head, and in the Fixion nail if its expanded body fits tightly in the distal canal. The benefit of “bio” nailing, my preferred technique, is the avoidance of distal locking screws, a procedure that is time-consuming and difficult in the humerus, endangers the radial and lateral cutaneous nerves in antegrade nailing, and the axillary nerve in retrograde nailing.23,26,151,170,173,197,257
Iatrogenic injury of the rotator cuff has been considered responsible for suboptimal clinical outcomes and shoulder joint discomfort after antegrade humeral nailing.79,247,315 However, apart from ongoing efforts to find less traumatic approaches to the proximal humerus or invent new implants that avoid violating the rotator cuff,70,221,285 it is my opinion that the consequences from the approach through the rotator cuff can be eliminated if96,97:
There is supportive evidence that antegrade intramedullary nailing, if performed correctly, may not be responsible for shoulder joint complications.82,84,92,150,200,211,220,253,263,285
Iatrogenic injury of vulnerable soft tissues (axillary nerve, circumflex artery, long head of biceps, deltoid) around the proximal humerus by the proximal locking screws in antegrade nailing and “fixed” retrograde nailing3,27,78,167,173,235 can be reduced by the use of necessary screws only and avoidance of an AP proximal locking screw if possible. Alternative proximal locking options for antegrade nailing that aim to reduce the problems from the proximal locking screws have been proposed but have not been validated with further studies.92,95 Problems from the proximal locking screws during antegrade nailing in middle and distal diaphyseal humeral fractures can be eliminated with the use of the retrograde technique. In these cases the nail can be shorter so that the proximal locking screws can be inserted just below the surgical neck of the humerus and avoid injury to the axillary nerve.96 Another good reason for choosing the retrograde technique for fractures located at the mid-distal humeral diaphysis is the biomechanical evidence that nailing from short to longer bone segments can improve the mechanical properties of the fixation construct because of better nail/bone interface purchase.169 This information is more valid for “bio” nails without distal locking screws and supports the use of retrograde nailing in more distal fractures.
In retrograde nailing, the entry portal must be wide enough to accommodate the eccentric insertion of the nail. The narrow humeral canal at the distal humerus can be enlarged with staged reaming because in this area there are no vulnerable soft tissues that can be harmed by the reamers. However, extra care is needed for the avoidance of fissuring or fractures at the supracondylar area, and meticulous washing out of the reaming debris must be performed at the end of the procedure.24,96
My last recommendation regarding the use of intramedullary nailing for the management of diaphyseal humeral fractures refers to the timing of surgery. As I do not favor humeral reaming and dynamization cannot be applied effectively in the arm, union of a humeral fracture relies a lot on the fracture hematoma. Therefore, the chances of uncomplicated healing for humeral shaft fractures are maximized if nailing is performed in fresh fractures, which in my practice is up to 2 to 4 weeks from accident. In cases where the fracture union progress seems delayed or can be characterized as delayed (3 to 6 months), I use “fixed” intramedullary nailing and percutaneous autologous concentrated stem cells at the fracture site.94
Established nonunion of a humeral shaft fracture is usually atrophic and in my opinion requires surgical debridement, autologous corticocancellous bone grafting, and rigid fixation that can be provided effectively by compression plating.
I treat open fractures without significant contamination with a U-slab and antibiotics for a few days (maximum 10 to 12 days), until the wound allows definitive treatment with intramedullary nailing. For open fractures with severe contamination and soft tissue compromise, I use external fixation with conversion to nailing or plating with the timing of the conversion depending on the extent and location of the soft tissue injury.
For pathologic fractures I also use intramedullary nailing (usually “fixed”) that offers a reliable, quick, and atraumatic solution that serves as palliative treatment.92,95