الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
A fracture pattern which places the humeral head at risk of avascular necrosis may be more likely to benefit from arthroplasty surgery rather than internal fixation compared to a pattern whereby the risk of devascularisation is low. The principal blood supply to the head has been shown to originate from the anterior humeral circumflex artery through the arcuate branch, although more recent work suggests the role of the posterior humeral circumflex artery is greater than previously thought. The presence of certain fracture patterns has been demonstrated to be associated with a higher risk of humeral head necrosis: a medial metaphyseal head extension less than 8 mm, disruption of the posteromedial hinge and any fracture pattern that disrupts the anatomical humeral head. The presence of any of these features should prompt the clinician to consider arthroplasty surgery as a more reliable treatment option.
Neer first described the use of hemiarthroplasty for proximal humeral fractures reporting a 98% satisfactory or excellent rate. The procedure provides immediate stability and provides patients with reliable pain relief following surgery. However its ability to restore normal shoulder kinematics and function is debated.
Indications for hemiarthroplasty include fracture dislocations and humeral head splitting fractures. A head splitting fracture in a young patient can pose a real treatment dilemma as the surgeon wants to avoid arthroplasty but this may not be technically feasible. The use of hemiarthroplasty in the management of displaced three and four part fractures is controversial and dependent on both patient and fracture factors.