Although most proximal humeral fractures occur in the elderly, a significant number also occur in younger individuals as well. When due to low-energy trauma many of these fractures are minimally displaced and stable, often allowing nonoperative management. However, when due to high-energy trauma, these fractures are generally significantly displaced, angulated, and malrotated and have fractures of the tuberosity and therefore benefit from operative intervention.

The Neer (1) classification system is commonly used to describe these fractures and is effective in relating both the severity of the injury and appropriate surgical management. In this system, the four anatomic regions of the proximal humerus (humeral shaft, humeral head, greater and lesser tuberosities) are identified, and the involvement of these structures in the fracture and degree of displacement are taken into consideration. Fractures therefore are generally classified as either one-, two-, three-, or four-part fractures, depending upon the number of fracture fragments present.

In this classification system, a fragment is considered displaced when it comes to rest 10 mm or more from its anatomic position or is angulated by more than 45 degrees from its original position (isolated fractures of the greater tuberosity may be an exception and may require operative reduction and fixation if superior displacement is 5 mm or more). One-part fractures are essentially nondisplaced fractures and are generally amenable to closed treatment. Two-part fractures can represent a variety of different fracture patterns, the most common of which has a displaced fracture of the surgical neck with the humeral head and tuberosities remaining intact but separated from the shaft. In three-part fractures, generally one of the tuberosities is fractured and displaced from the proximal humerus and the head and remaining tuberosity is displaced from the shaft. Four-part fractures involve separation of both tuberosities from the head, as well as displacement of the head (either with a fracture of the surgical or anatomic neck) from the shaft.

The classification also describes those injuries associated with dislocation of the head from the glenoid, in addition to a combination of fractures, and identifies these as having a significantly worse prognosis. It is apparent that the greater the number of fragments in a fracture, the greater the risk of avascular necrosis (AVN) of the
humeral head. As a result, three- and four-part fractures have the highest risk of AVN. For quite some time, it was widely accepted that most two- and only some three-part fractures were best treated with internal fixation, while some three- and most four-part fractures were best treated with prosthetic replacement. One exception to this rule was valgus-impacted four-part fractures in young patients with good bone stock. Surgical repair of these fractures have been associated with predictable success. With the advent of locking plate technology in general, and proximal humeral locking plates in particular, open reduction internal fixation (ORIF) of nearly all displaced proximal humeral fractures is becoming more common and the functional outcome of these patients seems to be improving as a result.

It is now widely accepted that most unstable two-, three-, and four-part fractures are best managed with surgical intervention to restore useful shoulder function. Few patients, regardless of age or associated medical conditions, will not benefit from surgical treatment of an unstable proximal humerus fracture. Specific indications for ORIF include open fractures, those that cannot be reduced closed, and fractures with associated neurovascular compromise and those that are not amenable to closed reduction and percutaneous fixation. Young patients with good bone stock, especially those with multiple injuries who may need to rely more on their upper extremities (UE) for ADLs, are also excellent candidates for ORIF with locking plates. Specific contraindications to surgery occur in patients with little hope of functional recovery, such as debilitated elderly patients or those with neurologic lesions that preclude useful muscle function of the extremity. The presence of severe rotator cuff arthropathy is a relative contraindication to repair and may be an indication for prosthetic shoulder replacement.

In recent years, lack of predictability in greater tuberosity healing in fractures of the elderly has resulted in some advocating primary reverse arthroplasty in acute four-part fractures in the elderly. The rationale is that lack of greater tuberosity healing can dramatically effect shoulder function adversely, and the reverse prosthesis is predominantly deltoid powered, making tuberosity healing, while desirable, not essential for a functioning shoulder.

Most proximal humeral fractures occur in elderly women after low-energy single-level falls. Generally, the bone of the proximal humerus is osteoporotic and provides for poor fixation when conventional plates and screws are used (2, 3). Hawkins et al. (2, 3) pointed out that the soft-tissue attachments of the rotator cuff tendons are usually strong in spite of poor adjacent bone quality. They demonstrated that these soft tissues provide excellent sites of fracture fixation when tension band wiring techniques are used. Furthermore, tension band wiring does not violate the subacromial space or lead to postoperative impingement and minimizes the stripping and interference with blood supply associated with plates. Nowadays, it is common for the proximal humeral locking plates to be used, with or without tension band wiring techniques, to address these injuries in the elderly. In younger patients, bone quality is usually superior, and this allows excellent fixation with plates (locking or nonlocking) and screws. Fractures in young patients that occur as a result of high-energy trauma can have severe metaphyseal comminution making repair more difficult. This metaphyseal comminution creates instability that precludes the use of the isolated screw and tension band technique, as it leads to excessive shortening with loss of deltoid power and inferior subluxation of the humeral head. In such cases, plates are needed to restore and maintain the normal length of the humerus. In the past, small fragment plates such as the cloverleaf plate were found to fit the proximal humerus well and provided for multiple screw purchase in the humeral head. Well-contoured locking plates that have a low profile have more or less replaced the use of conventional plates for the treatment of these difficult fractures. In many cases, a tension band wiring can be used in conjunction with plates to help neutralize the pull of the rotator cuff, which can significantly enhance the security of the fixation. In summary, two-part fractures (generally the greater or lesser tuberosity) in both young and old patients without significant comminution can usually be managed with a tension band wiring technique. Three- and four-part fractures, proximal humeral nonunions, and fractures with metaphyseal comminution are better treated with precontoured specialty plates featuring locking screw technology possibly in combination with tension band wiring technique.