Fractures of the Proximal Humerus David Rothberg, MDa,*, Thomas Higgins, MDb KEYWORDS Proximal humerus fracture Neer classification Fibular strut Shoulder arthroplasty KEY POINTS Proximal humeral fractures are common. Classification systems have evolved to develop treatment guidelines. Bone quality must be considered for treatment. Surgical stabilization may require augmentation. Arthroplasty must be considered especially in the elderly. INTRODUCTION common osteoporotic extremity fracture after hip fractures and distal radius fractures.1 Greater Proximal humeral fractures are common, with low- than 70% of these fractures occur in patients older energy injuries occurring in the elderly population than 60 years, with a 4:1 female/male ratio and an and less frequent higher-energy fractures striking incidence steadily increasing after the age of 40 young people. The decision to pursue operative years. or nonoperative treatment is driven by the func- Independent risk factors for proximal humeral tional goals and the degree of displacement of fractures include a recent decline in health status, the proximal humeral anatomic parts. Operative insulin-dependent diabetes mellitus, infrequent management is based on the ability to obtain walking, indicators of neuromuscular weakness, and maintain reduction, vascularity of the articular diminished femoral neck bone density, height/ segment, quality of soft-tissue attachments, and weight loss, previous falls, impaired balance, and bone porosity. Despite much study, the optimal maternal history of hip fractures.2 In a 3-decade treatment of significantly displaced fracture population-based study of osteoporotic proximal patterns remains controversial. humeral fractures, Palvanen and colleagues3 found that the incidence in patients older than 60 EPIDEMIOLOGY years increased by 13.7% per year of age. When adjusted for age, the incidence of proximal Fractures of the proximal humerus are common, humeral fracture increased in women by 243% occurring in 4% of the population. They are most and in men by 153%. This increase was attributed commonly attributed to low-energy falls, with to the expanding elderly population as well as the a smaller subset of high-energy injuries affecting increasing incidence in the risk factors mentioned a younger population, but overall incidence previously. Based on the observed trends, they increases as bone mineral density decreases. calculated that the incidence of proximal humeral Proximal humeral fractures are the third most fractures would triple by 2030. No disclosures relevant to this article. a Orthopaedic Traumatology, University of California at Davis, 4860 Y Street, Suite 3800, Sacramento, CA 95817, USA; b University Orthopaedic Center, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA * Corresponding author. E-mail address: [email protected] Orthop Clin N Am 44 (2013) 9–19 http://dx.doi.org/10.1016/j.ocl.2012.08.004 0030-5898/13/$ – see front matter Ó 2013 Elsevier Inc. All rights reserved. orthopedic.theclinics.com 10 Rothberg & Higgins ANATOMY whereas the posterior humeral circumflex is intact in 85%. In magnetic resonance imaging angiog- The 4 basic osseous structures that serve as the raphy studies, Hettrich and colleagues5 showed basis for restoration of normal anatomy after that the posterior humeral circumflex artery may reduction are the articular surface proximal to the perfuse up to 64% of the humeral head, which anatomic neck, greater tuberosity, lesser tuber- explains the clinical finding of perfusion after frac- osity, and humeral shaft. The articular segment ture. Studies using different evaluation tools have has no muscular attachments. The supraspinatus, shown contradicting findings, but there seems to infraspinatus, and teres minor muscles attach to be fracture-specific predictors of humeral head the greater tuberosity; the subscapularis attaches ischemia. Hertel and colleagues6 showed that to the lesser tuberosity; and the deltoid, pectoralis humeral head ischemia could be predicted with major, teres major, and latissimus dorsi attach to a 97% positive predictive value when the meta- the humeral shaft. The normal osseous relation- physeal head extension length was less than 8 ships define goals for reduction. In the coronal mm, when there was disruption of the medial hinge plane the humeral head is inclined to the shaft by between the humeral head and shaft, and when a neck shaft angle of 130 to 150 . The humeral there was an anatomic neck component (Fig. 1). head center is offset medially 4 to 14 mm from the center of the shaft and À2 to 10 mm posteriorly. EVALUATION The most proximal aspect of the humeral head Mechanism of Injury articular surface is 8 mm from the tip of the greater tuberosity. In the sagittal plane, the humeral head History reveals one or a combination of mecha- is retroverted to the shaft by 0 to 55 . nisms occurring to produce a fracture of the prox- Given the propensity for avascular necrosis of imal humerus: (1) direct blows in the setting of the humeral head after proximal humeral fracture, high-energy trauma, (2) falls from standing height, the perfusion of this area has been the focus of (3) axial loads, (4) excessive internal rotation and much study. The primary vascular supply to the adduction forces. humeral head is through the anterior humeral circumflex artery. In a latex injection dissection Clinical Evaluation study, Gerber and colleagues4 showed the ante- After evaluation for concomitant upper extremity, rior humeral circumflex artery to originate from neck, and chest wall injuries, as may be present the axillary artery at 1 cm distal to the pectoralis in high-energy trauma, a thorough neurovascular major, running between the short head of the examination is performed. Motor evaluation of biceps and the coracobrachialis and reaching the the brachial plexus innervation is performed by surgical neck of the humerus at the inferior border evaluating the deltoid, biceps, triceps, and wrist of the subscapularis. The most important branch, flexors/extensors and hand intrinsics motor exam- the anterolateral branch, traverses under the long ination. So-called pseudoparalysis, thought to be head of the biceps adjacent to the lateral border secondary to swelling and pain, may make this of the intertubercular groove, entering the head examination difficult, and the presence of deltoid at the transition of the intertubercular groove and function does not always rule out an axillary nerve the greater tuberosity. Once the vessel penetrates injury. Axillary nerve neuropraxia is the most the head, it runs as the arcuate artery, posterome- common deficit in the setting of proximal humeral dially within the epiphysis, supplying all but a small fracture. Sensation is evaluated through der- portion of the posteroinferior portion of the epiph- matomal light touch examination, and careful ysis and the adjacent posterior portion of the evaluation of perfusion to the hand should be greater tuberosity. The posterior humeral circum- documented as well. flex artery arises from the axillary artery and perfuses the posteroinferior portion of the epiph- Associated Injury ysis and the posterior greater tuberosity anasto- mosing with the anterior humeral circumflex Vascular injury to the axillary artery, although rare, artery in the region of the joint capsule and greater may have devastating consequences if not identi- tuberosity.4 fied. It may present as obvious acute ischemia or Further study into the humeral head blood subtly as increasing pain, loss of sensation, and supply after fracture shows that, although the axillary swelling with ecchymosis. The axillary anterior humeral circumflex artery is the main artery is at risk as it crosses medial to the head blood supply, the head may stay perfused despite and surgical neck of the humerus and may be its frequent disruption. The anterior humeral damaged by direct laceration from displaced circumflex artery is disrupted in 80% of fractures, fracture fragments or by traction to the upper Fractures of the Proximal Humerus 11 Fig. 1. Hertel’s radiographic criteria. Metaphyseal extension is the measured distance from the head–neck junc- tion to the inferior extent of the medial cortex. (A) Metaphyseal extension greater than 8 mm. (B) Metaphyseal extension less than 8 mm. The medial hinge is evaluated at the medial calcar. (C) Intact medial hinge. (D) Medial hinge displaced greater than 2 mm. (Adapted from Hertel R, Hempfing A, Stiehler M, et al. Predictors of the humeral head ischemia after intracapsular fracture of the proximal humerus. J Shoulder Elbow Surg 2004; 13:427–33; with permission.) extremity. Prompt arteriography and subsequent role of the rotator cuff tear in the functional repair is necessary and may be timed with fracture recovery of proximal humeral fractures is incom- fixation to prevent further injury. pletely defined. Two reports on the functional A significant factor in the outcome of proximal outcome in conservatively treated proximal humeral fractures is associated injury to the humeral fractures with rotator cuff tears are incon- brachial plexus. Neurologic injury associated with clusive with respect to outcome; therefore, proximal humeral fracture is most common in the advanced imaging for complete evaluation of the axillary nerve distribution. Large fracture fragment rotator cuff in the setting of proximal humeral frac- displacement with associated hematoma devel- ture cannot be recommended at this time. opment and