Osteonecrosis of the Humeral Head

Osteonecrosis of the humeral head (ONHH) is thought to occur when the vascularity of the proximal part of the humerus is impaired. Traumatic ONHH can be seen after humeral neck fractures, shoulder dislocations, or surgery of the shoulder. However, the majority of ONHH related to humeral neck fractures is quickly revascularized with creeping substitution without collapse, and the clinical impact of ONHH in fracture cases is relatively small compared to the fracture itself. Nontraumatic ONHH is an uncommon disease. Before steroid-associated osteonecrosis had been recognized, nontraumatic osteonecrosis could be caused by vascular occlusion due to systemic diseases, such as Gaucher’s disease, sickle-cell disease, caisson disease, and collagen vascular diseases. Since Heimann and Freiberger first reported two cases with steroid-induced ONHH, the number of reports about it increased, and steroid is the most frequently observed etiology of nontraumatic ONHH nowadays. Steroid-associated ONHH often manifests itself as multiple or multifocal osteonecrosis with an incidence of 3% in osteonecrosis patients. The shoulder is one of the major affected sites of osteonecrosis secondary to the hip and knee. Plain radiographs are essential for the diagnosis of ONHH and staging. However, MRI is useful for the early diagnosis of ONHH and evaluation of the extent of the necrotic lesion. Staging is the most objective criterion in determining the treatment methods. Conservative treatment can be effective in stages I and II (precollapse stages) when patients’ symptoms are relatively mild. When symptoms persist and collapse progresses despite conservative treatment, surgical interventions including core decompression, vascularized bone grafting, arthroscopic debridement, and shoulder arthroplasty are considered.