Shoulder Fractures and Separations
There are three primary bones that make up the shoulder complex. The clavicle (or collarbone) connects the sternum and the main part of the skeleton to the scapula (or shoulder blade). The scapula is only held in place by the acromioclavicular (AC) joint between the clavicle and scapula and muscles that attach it to the chest wall. Suspended from the scapula is the humerus. It is only held to the scapula by thin ligaments and muscles/tendons that compress the humeral head (ball) into the glenoid (socket). Fractures of any of these bones or a separation of the AC joint can affect the attachment of the arm to the rest of the body. This can potentially limit mobility and use of the shoulder.
Bones of the shoulder
Fractures of the clavicle are one of the more common fractures (4% of all fractures) and are frequently in young active people. Because of its suspension between the arm and chest wall, it can easily break from a fall on the point of the shoulder or outstretched arm. The clavicle is also not covered by muscles and is easily felt directly under the skin. This makes it susceptible to a direct blow and subsequent fracture. Many fractures have some amount of displacement. The weight of the arm pulls the outer part of the clavicle down. This causes the top of the fractured bone to be prominent and the shoulder to droop.
X-Ray and photo of clavicle fracture with the inner (medial) fragment prominent at the top and the outer (lateral) fragment with the arm drooping down
Despite the displacement of the fracture in many people, the fracture is often managed without surgery. The fracture will not remain in place if reduced. The weight of the arm and pull of the muscles will cause the fracture to return to its original position. Therefore, either the fracture is allowed to heal in the current position or it is surgically reduced and held with a metal plate or screws. Up to 2 cm (almost one inch) of displacement can be accepted in younger patients. Despite the lack of direct contact between the bones, the body is able to bridge the gap and heal the fracture in most circumstances. However, the bony prominence at the fracture site may persist. The clavicle is the last bone in the body to stop growing around age 21 and can remodel or straighten itself as it grows. In pediatric patients, surgery is rarely necessary. Despite significant displacement, the fracture will heal and the deformity will remodel with growth. A sling is worn for approximately 4 weeks. There is a risk of re-fracture for up to one year after the injury until the bone has sufficiently strengthened.
In adults, there is no potential for remodeling so the prominence will be more evident. Shortening of the fracture may also affect strength and endurance. Up to 5% of displaced fractures in adults will not heal. This risk is greater in smokers, females and fractures with multiple fragments. Fractures that are 100% displaced or shortened by over 2 cm should be treated with surgical open reduction and internal fixation (ORIF). Either a metal plate or internal screw can be used for fixation. Fractures with less displacement are occasionally treated with surgery for patients requiring more normal strength and endurance in the shoulder or cannot tolerate immobilization in a sling for a month.
Clavicle fracture ORIF
In contrast to the frequency of clavicle fractures, scapula fractures are uncommon. They are usually associated with significant trauma including rib fractures, spine fractures or injuries to the lung and major blood vessels. These fractures typically heal well as they are surrounded by muscle and have a good blood supply. Only fractures that are displaced by more than 1 cm (half an inch), angled more than 40 degrees, or involve the joint surface require surgical treatment. This requires a large exposure to lift the muscles away from the scapula, align the fracture and apply several large contoured plates to wrap around the edge of the scapula.
Scapula fracture CT scan – typical appearance with multiple fragments
Scapula fracture open reduction and internal fixation – multiple plates needed for repair
Proximal Humerus Fractures
Fractures of the top (proximal) portion of the humerus are the third most common type of fracture in the elderly (behind wrist and hip). The bone of the humeral head frequently becomes softer as a result of osteoporosis. A low energy fall can easily result in a fractured shoulder. It is twice as common in women due to the association with osteoporosis. Fractures can also occur in younger patients but is associated with a greater degree of trauma. Fractures through the proximal humerus usually involve 4 separate areas of the bone. Most commonly, fractures will occur at the base of the humeral head through a weaker area of the bone called the surgical neck. Fractures may also extend through the areas of the bone where the rotator cuff inserts (greater and lesser tuberosities) resulting in two additional fracture fragments. The fourth fragment is the rest of the humeral bone (shaft). The amount of displacement and angulation of the fragments determines the treatment. The majority (85%) of proximal humerus fractures are minimally displaced and treated without surgery. Up to 5 mm (quarter of an inch) of displacement of the tuberosities and up to 40 degrees of angulation of the humeral head can be accepted without requiring surgery in older patients.
Humeral Head Lesser Tuberosity Greater Tuberosity Surgical Neck
Fracture pattern for proximal humerus fractures
Fractures of the proximal humerus usually result in some loss of overhead movement despite the method of treatment. In minimally displaced fractures, a sling is worn for 4 to 6 weeks but early range of motion is started after a few weeks to reduce the amount of stiffness that occurs. Physical therapy is often required for several months to improve mobility.
Displaced fractures, especially in younger patients, are often managed with an open reduction and internal fixation (ORIF). Occasionally, the fractures can be reduced into a better position without surgically opening the shoulder. If so, pins can be inserted through the skin to hold the fragments in position. To provide better stability, the fracture may be opened, placed back into its original position and held with a metal plate and screws. Insertion of a metal rod with locking screws through the rod is another alternative for some fracture patterns. After placement of the rod or plate, physical therapy for shoulder range of motion can be started immediately to reduce the risk of stiffness. The plate and screws are strong enough to hold the fragments in position for the shoulder to be moved.
Examples of ORIF of the proximal humerus with a plate.
ORIF of proximal humerus fracture with a rod and screws
Significantly displaced fractures of the proximal humerus in elderly patients are treated with a shoulder replacement. The blood supply to the humeral head may be damaged by the fracture and the bone may subsequently die. One risk of ORIF is failure of the fracture to heal because of the poor blood supply or avascular necrosis where the bone dies and collapses. This risk increases with advancing age and severity of the fracture. To avoid the potential complication, the humeral head can be replaced (hemiarthroplasty) and the fractured tuberosities repaired around the replacement prosthesis. Recently, reverse shoulder replacement in elderly patients has yielded better results for these fractures as the range of motion is frequently improved.
Reverse replacement for fracture
AC joint separations
A shoulder separation refers to a separation of the joint between the clavicle and the acromion process of the scapula, the acromioclavicular or AC joint. These injuries often occur from a fall directly on the point of the shoulder. As the scapula is pushed downward by the blow to the shoulder, the clavicle is displaced upward. The ligaments that support the joint are stretched and eventually torn. The end of the clavicle will become prominent as it shifts upward. The amount of displacement is used to categorize the fracture and determines the treatment. A Type 1 sprain has no displacement and only some tenderness at the joint. These heal well and treatment is based on symptoms. A Type 2 separation is a result of partial tearing of the ligaments with 25% displacement of the joint. These also heal well without specific treatment. A Type 3 separation is due to complete tearing of all the ligaments with up to 100% displacement of the joint. Even though there may be a significant prominence noted on top of the shoulder because of the displaced clavicle, these also heal well in most people. Elite non-contact athletes or heavy laborers may have problems from the displacement and require surgical repair. Type 4-6 separations are more severe displacements often greater than 100% and require surgical repair. During surgery the clavicle is reduced back to the acromion and held in place with a tendon graft and heavy sutures. This can be done with the arthroscope or open. There is less scarring if done arthroscopically, but a slightly greater incidence of residual prominence of the distal clavicle as the repair may stretch out over time.
AC joint separations
Appearance of 100% displaced AC separation on right side
Arthroscopic repair of torn AC ligaments with tendon graft and heavy sutures
Key points to treating shoulder fractures and separations:
1. Many fractures and separations can be treated without surgery.
2. Many shoulder fractures result in some loss of shoulder motion, even in the best of circumstances.
3. Surgical treatment of shoulder fractures is a difficult procedure because there are often multiple fragments displaced around a complex joint.
4. Choosing a specialist in managing these fractures will provide the best scenario for improving shoulder function long-term.
5. You have the ability to choose your surgeon. Nearly all shoulder fractures are not repaired urgently and usually you can be released from the emergency room. You do not have to be treated by the “on call” doctor who may have little experience in treating these injuries. Contact a shoulder specialist with experience in managing these complex fractures. Fractures and separations can be repaired up to 3 weeks after the initial injury.