Protective and Risk Factors for Humerus Head Necrosis After Proximal Humerus Fracture Treated with Internal Locking Plate.

backgroundProximal humerus fractures (PHF) are common and lead to post-traumatic humerus head necrosis (HHN) in 3-35% after ORIF with an internal locking plate. Few studies focus on this condition and risk factors remain a discussion topic. Hertel's criteria for initial head ischemia right after fracture (fracture complexity, medial hinge displacement and short metaphyseal head extension) have recently been correlated to HHN, but there is still a clear lack of evidence on the topic. Due to its anatomical similarities to the proximal femur, some authors argue that PHF may as well benefit from early surgery to avoid head necrosis.

methodsIn this 10-year retrospective study, we assessed 305 patients from a single center. All cases were treated with a PHILOS plate through a deltopectoral approach. The mean follow-up time was 467 days. The primary endpoint was HHN.

resultsHHN was diagnosed in 12 patients (4%), 10 of which were diagnosed within the first year and one case 4 years after surgery. A positive correlation (

conclusionWe conclude that fracture complexity (four-part and C-fractures) as well as disruption of the medial hinge with a metaphyseal head extension smaller than 8 mm are relevant risk factors for humerus head necrosis. A combination of these criteria generated an high risk pattern with a 32% rate of HHN. Though often difficult to achieve, perfect reduction was a clear protective factor and reduced HHN to 0%. Perfect reduction may be key to inosculation and, therefore, salvage of the humerus head, especially in high risk cases. Surgery timing did not correlate with HHN. LEVEL OF EVIDENCE: Level 3, retrospective cohort study.