A proximal humerus fracture is a break in the upper portion of the humerus. This injury is relatively common, representing about five to six percent of all adult fractures. It is seen frequently in the elderly, often linked to low-energy falls and underlying conditions like osteoporosis. Understanding the anatomy, severity, and management of this injury is key to recovery.
Anatomy and Definition of the Fracture
The proximal humerus forms the ball component of the shoulder’s ball-and-socket joint, articulating with the socket of the shoulder blade, or scapula. This upper end features the humeral head and two bony bumps: the greater and lesser tuberosities. These tuberosities serve as attachment points for the rotator cuff muscles, which stabilize the shoulder and facilitate movement.
Fractures often occur at the surgical neck, the narrow area just below the tuberosities and the most frequently fractured site in older individuals. The anatomical neck is a less common fracture site, located directly beneath the humeral head. Fractures in this region can lead to significant issues due to their proximity to the shoulder joint, tendons, and nerves.
Identifying the Injury: Causes and Symptoms
The mechanisms that cause a proximal humerus fracture differ depending on the patient’s age. In older adults, the most frequent cause is a low-energy fall from a standing height onto an outstretched arm or directly onto the shoulder. This is often compounded by reduced bone density.
In younger individuals, the injury typically results from high-energy trauma, such as a motor vehicle accident or a fall from a significant height. Patients experience severe pain and immobility immediately following the injury. Visible signs include rapid swelling and substantial bruising that can spread down the arm and across the chest.
A physical examination is performed, followed by medical imaging to confirm the diagnosis and determine the extent of the damage. Standard X-rays are usually sufficient, but a computed tomography (CT) scan may be ordered to better visualize fragment displacement and assess the joint surface. The clinical evaluation also includes a neurovascular assessment, as the proximity of the fracture to the axillary nerve and artery means that nerve damage, though uncommon, is a possibility.
Classifying the Severity of the Break
The severity of a proximal humerus fracture is determined by the number of bone fragments and the degree of separation between them. The Neer classification system is commonly used, dividing the proximal humerus into four segments: the humeral head, the greater tuberosity, the lesser tuberosity, and the shaft. This system guides the appropriate treatment plan.
Classification is based on the number of displaced segments. Displacement is defined as a separation greater than one centimeter or an angulation of more than 45 degrees. The simplest and most common injuries are minimally displaced, or one-part, fractures, which account for the vast majority of cases.
More complex injuries are classified as two-, three-, or four-part fractures, depending on how many segments meet the criteria for displacement. For instance, a two-part fracture involves one displaced segment, while a four-part fracture is a severe injury where all four segments are significantly separated and malrotated. This standardized system communicates the complexity of the injury, directly impacting treatment decisions.
Treatment Options and Rehabilitation
The treatment path for a proximal humerus fracture is linked directly to the severity of the break. The majority of these fractures, specifically those that are non-displaced or minimally displaced, are managed without surgery. Non-operative management involves immobilizing the arm, typically in a sling, for a short period to allow for initial bone healing.
During this phase, patients perform gentle exercises for the elbow, wrist, and hand to prevent stiffness. The primary goal of non-operative treatment is to maintain acceptable alignment while protecting the blood supply to the humeral head. This approach is often as effective as surgical intervention for less complex fractures, particularly in older patients.
Operative management is reserved for displaced fractures, such as three-part or four-part injuries, where fragments are significantly separated or the joint surface is involved. Surgical options include Open Reduction and Internal Fixation (ORIF), where the surgeon realigns and secures the fragments with plates, screws, or pins. If there is severe comminution or compromised blood flow to the humeral head, a shoulder replacement, or arthroplasty, may be necessary to restore function.
Rehabilitation through physical therapy is a crucial part of the recovery process. The timeline for recovery is lengthy, frequently requiring six to twelve months for a return to near-normal function. Physical therapy begins with passive and assisted range-of-motion exercises, such as pendulum exercises, initiated early depending on fracture stability. Strengthening exercises, focusing on the rotator cuff and surrounding muscles, are progressively introduced once X-rays confirm bone healing, often starting around six to eight weeks.