Angular stable fixation of proximal humeral fractures.

Background: Proximal humeral fractures requiring surgical stabilization remain a therapeutic challenge. High rates of treatment-related complications have been reported to be associated, particularly in elderly patients with unstable fracture types and diminished bone quality. In recent years, angular stable implants have been introduced to improve the patients' outcome. The purpose of this study was to assess the clinical and radiographic long-term results after angular stable plate fixation of proximal humeral fractures at this Level I trauma center, with special emphasis on fracture healing, functional outcome and treatment related complications.

Methods: We retrospectively analyzed functional and radiographic results of 42 patients (average age: 57.8 years) after angular stable plate fixation of proximal humeral fractures at an average time of 3.2 (+/-0.8) years after trauma. Functional results were defined by the Constant shoulder score (CS) and the individual Constant score (CSindiv). Radiographic results were assessed by a three-view trauma series (anteroposterior, lateral, and axillary view). For operative treatment, two different angular stable implants were used. Twenty-seven patients were stabilized by a HOFER plate, fifteen patients by a Locking Proximal Humerus Plate.

Results: Clinical results revealed an average CS of 74.0 points and an average individual CSindiv of 79.2% points. Fourteen patients had an excellent functional outcome, eight patients a good outcome and fourteen patients had moderate functional results. Six patients (14%) had a poor outcome with less than 55% on CSindiv. Regarding the radiographic outcome, we had an overall union rate of 95% (40 of 42). Failures of reduction and fixation occurred in fourteen patients (33%), and in nine patients (21%) we had signs of a humeral head necrosis. Re-operation due to treatment-related complications was necessary in two patients (5%). Statistical analysis revealed that the fracture type and the age of the patients had a significant influence on the clinical outcome and on the incidence of treatment-related complications.

Conclusion: With regards to fracture healing and functional outcome of the patients, we had a satisfactory outcome after angular stable plate fixation of proximal humeral fractures. However, we experienced a notably high rate of technical failures and partial humeral head necrosis. Advanced surgical skills and experiences are necessary to achieve correct anatomic reduction and implant fixation, to reduce the risk of these treatment-related complications.