Surgical treatment of displaced proximal humerus fractures with a short intramedullary nail

BackgroundThe Polaris nail is an intramedullary device for treating displaced proximal humerus fractures with few published studies to support its use. Results of a consecutive series of patients treated with the Polaris nail are presented.MethodsEighteen patients with a mean age of 71 years (range, 37-84) were treated for twelve 2- and six 3-part fractures. Radiographic results for all patients were evaluated. Thirteen patients with an average follow-up of 42 months (range, 24-84) were available for functional evaluation.ResultsSeventeen of 18 patients healed. Postoperatively, the neck/shaft angle collapsed an average 11° (range, 5-30°) into varus. Nine of 18 patients had final neck/shaft angles <120° and were considered radiographic malunions. The mean Constant and American Shoulder and Elbow Surgeons (ASES) scores were 61 (range, 20-100) and 67 (range, 10-100), respectively. Forward elevation averaged 118°. Patients had an average 5/8 positive rotator cuff signs. Seven patients underwent reoperation for loss of fixation or prominent hardware, and 1 required revision to a hemiarthroplasty.ConclusionThis study shows a higher than reported percentage of unsatisfactory results using the Polaris nail. The device violates the rotator cuff and is unable to resist the deforming forces that can lead to loss of fixation and varus collapse.