What are the potential complications of this fracture?
Complications are events or conditions which make the process of recovering from the fracture more complex. Although most of them are rare, much of the management of the injury is directed at avoiding or reducing the extent of complications. More detail on complications is provided in A Patients Guide to Adult Fractures. Here we will focus on complications that have a major effect on the management of shoulder fractures.
Related Document: A Patient's Guide to Adult Fractures
Injuries to the brachial plexus were referred to above. If the injury is complete the prognosis for full recovery is poor as the nerves have a long way to grow before they re-attach to their "targets" in the hand and forearm. Even after surgery to repair the nerves the outcome cannot be predicted. More often the injury is a stretch and recovery is slow but complete. If a brachial plexus injury does not fully recover, the treatment depends on the disability and the needs of the patient. Muscle transfer operations to restore the function of the elbow and hand may be needed.
Injury to the axillary nerve after a dislocation also usually recovers. This nerve is close to the upper end of the humerus and may be damaged during surgery for ORIF.
After an open fracture there is a risk that the contamination at the time of the injury will result in a bacterial infection. After surgery on a fracture the risk of surgical site infection is 2% or less.
If the wound remains swollen, tender and red longer than normal an infection must be suspected. A fever may occur and pus may accumulate in the wound or drain from it. Culture of the pus or blood cultures may isolate the bacteria causing the infection. This problem requires high doses of antibiotics for an extended period.
Usually it is also necessary to repeat surgery to remove contaminated and non-viable tissue, wash out the wound and drain it. Antibiotic beads are often placed in the wound so there is a high local concentration of the drug.
With early aggressive management it is usually possible to suppress or eliminate the infection until the fracture heals. At that point removal of any remaining metal implants usually allows the infection to heal completely with no long term sequellae. Where an infection of bone is incompletely healed, it may be quiescent for some years and flare up later when the patient is stressed.
After dislocation of the glenohumeral joint the ligaments may be pulled off the front of the glenoid and do not re-attach securely. The shoulder is then at risk for repeated dislocations, each of which will further stretch and damage the structures that normally prevent dislocation.
This situation frequently results in surgery to reconstruct or re-attach the ligaments. Recurrent instability may also occur at the acromioclavicular joint and the sternoclavicular joint if they have been injured. Treatment of these problems depends on the individual situation.
Related Document: A Patient's Guide to Shoulder Dislocations
Malunion means that the fracture heals in an incorrect position. This is frequently asymptomatic; the shoulder-blade often unites with fragments overlapping or rotated. However, because it acts primarily as a site of attachment for muscle the new shape does not affect function and is rarely noticeable. The collarbone is just under the skin and any malunion can be felt as a swelling or overlap. In rare cases spicules of bone from an angulated clavicle fracture may work their way through the skin and may need to be trimmed off.
The worst problems with malunion occur in relation to joints. If an avulsion fracture of the greater tuberosity heals malunited it may impinge on the acromion process in abduction. This situation can be treated with surgery to recess the tuberosity back into position and fix it. If the fracture involves the joint surface itself malunion may mean that the joint surface is irregular. This predisposes to early post traumatic arthritis. If the malunited fracture involves glenoid it may be possible to operate to move the fragment back into position and make the joint surface smoother. Because of problems with the blood supply this may not be advisable in the case of malunited fractures of the head of the humerus.
When a fracture has failed to heal and will not heal without further intervention it is called a nonunion. This is unusual in all the bones of the shoulder girdle except the collarbone. Even there it is rare but can be troublesome with pain and tenderness limiting function of the arm. Treatment involves surgery, bone grafting and fixing the fracture with a plate and screws. This procedure is successful in healing the fracture 90% of the time. Because of the possibility of nonunion and concerns about malunion of the collarbone some surgeons are recommending ORIF for the initial injury in selected patients. When a collarbone has been treated in this way the plate is usually just under the skin. It is uncomfortable especially with shoulder straps and it may be necessary to do a second operation to remove the plate. Nonunion in proximal humeral fractures occurs in the context of fixation failure (see below).
Metal that is repeatedly stressed will feventually undergo fatigue failure. We do this commonly with wire, wiggling it up and down until it breaks. This is true of metal implants used in fracture treatment - the "wiggle" is supplied by micro-movement at the fracture site. It is a race between the bone healing and the metal failing, which the bone usually wins.
In cases of delayed or non union, cases where the fixation is weak, or cases where the shoulder is loaded early before the bone has healed, the hardware may fail. This is the reason for restrictions on using the shoulder too early. Even though the shoulder may feel painless and strong, if it is still dependent on the metal for its strength, it makes no sense to test that strength.
Hardware failure can sometimes be treated nonoperatively by resting and immobilizing the shoulder and expecting healing to progress. Often it requires repeat surgery. The restrictions on activity imposed by the surgeon and physical therapists are aimed at avoiding this complication.
Another problem that is specific to the shoulder region is the quality of the bone. Many fractures occur in the elderly with osteoporotic bone. Bone that is osteoporotic does not hold screws well and loss of fixation can occur when screws pull out of the head of the humerus. Modern plate designs with locking screws are aimed to avoid this problem but this is only partly successful. Failure of fixation for whatever cause makes nonunion or malunion more likely.
Post Traumatic Arthritis
Where a joint has not moved for a long time, where the joint surface was damaged as part of the injury or where the joint surface is irregular one, can expect the joint surface to wear out prematurely. This is called post traumatic arthritis. The shoulder will become aching and painful to move or load; the range of motion of the joint will become restricted; and the x-rays show loss of joint surface, spurs, and loose bodies in the joint.
This process takes years but may be a severe functional problem in a younger patient. The symptoms can be treated with pain medication and anti-inflammatory medication (NSAIDs) and physical therapy may be helpful in retaining range of motion. In cases with severe pain a shoulder replacement may be the outcome.
Injury often causes bleeding into a joint. This blood clots (coagulates) but remains in the joint. Eventually the clot is transformed into scar tissue. If the joint remains immobile while this scar tissue forms, it may adhere to different parts of the joint and bind them together (adhesions). This will result in loss of range of motion (stiffness) of the joint and sometimes pain when the scar is stretched. With three joints involved in a shoulder injury it is not unusual for one or more of them to stiffen up during the recover process particularly if the shoulder needs to be immobilized for a long period.
Preventing this stiffness is the reason for early pendulum exercises or circus movements of the shoulder. At the earlier stage of blood clot, the tissue has no strength and can easily be stretched. It is painless too; the developing adhesion has no nerve supply at that stage. Later on the adhesions may also be stretched but this is an altogether different affair, both slow and uncomfortable, and may not be completely successful.