The most common mechanism of injury in a proximal humerus fracture is trauma to the arm or shoulder, such as occurs with a fall onto an outstretched hand. Fractures of the proximal humerus usually involve the humeral shaft, surgical neck, or the sites of muscle attachment (greater or lesser tuberosities). Fractured bones may remain in alignment (nondisplaced fracture) or fragments may separate and become misaligned (displaced fracture). Displaced fractures most commonly involve the surgical neck of the humerus. The degree of fracture displacement is dependent upon the direction of pull of the muscles that attach to the tuberosities. Greater tuberosity fractures account for 15% of proximal humerus fractures, and are associated with anterior shoulder dislocations one-third of the time. Shoulder dislocation may occur with proximal humeral fracture (fracture-dislocation).
Athletes and older individuals, particularly post-menopausal women with osteoporosis, are at greater risk of sustaining proximal humerus fractures. Among younger individuals, high-impact sports activity is a frequent cause. Proximal humerus fractures are twice as common in women as in men, largely due to the increased incidence of osteoporosis in women.
Proximal humerus fractures account for 5% of all fractures. Incidence increases with age. Proximal humerus fracture is a major cause of morbidity in individuals age 65 and older.
Swelling (edema) and bruising (ecchymosis) may be evident on the arm, around the shoulder and chest wall. The full extent of ecchymosis may not be visible until 24 to 48 hours after injury. If the fracture is displaced, there may be an obvious deformity of the arm, and muscle spasms may be present. Upon examination, the individual is usually unable to lift the arm without assistance.
Thorough neurologic testing of the muscles of the forearm, wrist, and hand should be performed to determine if nerve injury has occurred. Electromyography (EMG) may need to be performed if nerve injury is suspected. Radial and ulnar pulses of the affected arm should be checked as a weak or absent pulse could indicate vascular injury.
Plain x-rays in a trauma series (anteroposterior [AP], lateral views in scapular plane, and axillary views) show most fractures of the humerus and define extent and type of injury. Axillary views allow assessment of tuberosity fragments and dislocation of the head of the humerus. CT scans may be necessary to check for a fracture-dislocation.
The goals of treatment are to control pain with non-steroidal anti-inflammatory drugs (NSAIDs), analgesics, and/or narcotic pain medication during the recovery period and to restore function of the injured arm. The majority of proximal humerus fractures are nondisplaced and do not occur within the joint (intra-articular). To treat a nondisplaced humerus fracture, the arm is placed in a sling or shoulder immobilizer.
Surgical approaches will differ depending on the degree of bone separation, location, presence of osteoporosis, and whether the bone has broken into several pieces (comminuted fracture). Surgical treatment may be closed reduction with percutaneous fixation, open reduction with internal fixation (ORIF), or humeral head replacement (shoulder reconstruction, shoulder hemiarthroplasty). ORIF may involve the insertion of wires, pins, screws, or an intramedullary rod or nail to realign fracture fragments. This procedure is more commonly used in younger individuals. Prosthetic shoulder replacement may be necessary for comminuted three- and four-part fractures, fractures that split the humeral head and in older persons. The rotator cuff may need to be reconstructed if the fracture occurred near the attachments.
The goals of rehabilitation following a proximal humerus fracture are first to decrease pain and then to return the individual to full function with a pain-free shoulder. Protocols for rehabilitation must be based upon stability of the fracture and whether fracture management was operative or nonoperative.
The amount and intensity of therapy required will be determined somewhat by the pre-injury occupational and leisure activities that the individual wishes to resume.
Bone healing may occur within 6 to 12 weeks; however, bone strength and the ability of the humerus to sustain a heavy load may take up a year to return.
Most humerus shaft fractures require a year for complete recovery. The prognosis will depend on the individual’s age, overall health status, adherence to rehabilitation, and stability of the fracture if surgery is performed. Patient compliance, medical comorbidities and time between injury and treatment may affect outcome. |
