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Complications and Special Considerations

Fracture of the proximal humerus presents a therapeutic challenge. Numerous complications have been reported. Most common complications include AVN, malunion, neurovascular injury, and adhesive capsulitis (frozen shoulder). Hardware failure, infection, and nonunion are less common.

AVN is a common complication following three- and four-part fractures. The incidence of AVN of the humeral head ranges from 21% to 75% . Although the exact mechanism leading to necrosis is not known, it seems that disruption of the anterior humeral circumflex artery and its branches during the injury play a critical role in development of this complication. The treatment of choice for symptomatic AVN is a humeral head arthroplasty.

Malunion is a complication occurring after inadequately closed reduction or failed open treatment. The treatment is often challenging because of excessive scarring and retraction of the fragments. Angulation or rotational malunions are treated with osteotomy and internal fixation. If malunion is associated with AVN or post-traumatic degeneration, humeral head arthroplasty or total shoulder replacement may be considered.

Neurovascular injuries occur as an associated injury during proximal humerus fracture or as a complication of surgical treatment particularly percutaneous pinning. The main trunk of the axillary nerve and posterior humeral circumflex artery is at risk during placement of the greater tuberosity pins. The anterior branch of the axillary nerve can be damaged during placement of the proximal lateral pin, and musculocutaneous nerve, cephalic vein, and biceps tendon can be injured during the anterior pin placement.

Rehabilitation is an essential part of the therapeutic plan for a proximal humerus fracture. Early range of motion exercises help prevent adhesive capsulitis (frozen shoulder) that impede adequate motion necessary for optimal function. Initial management consists of an early, staged exercise program. Patients with a frozen shoulder unresponsive to
conservative treatment may be considered for arthroscopic debridement of glenohumeral joint and subacromional space and selective capsular release combined with manipulation under general anesthesia. Manipulation under general anesthesia as a stand-alone procedure has also been described and has demonstrated improvement in range of motion.

Although manipulation under anesthesia was effective in terms of joint mobilization, the method can cause iatrogenic intra-articular damage such as iatrogenic superior labrum anterior-posterior lesions, partial tears of the subscapularis tendon, anterior labral detachments with a small osteochondral defect, or tears of the middle glenohumeral ligament .

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