Orthopaedic Surgery, Mayo Clinic, Rochester,Minnesota, United States.

Orthopaedic Surgery, Hospital Universitario la Paz, Madrid, Spain.

Radiology Department, Hospital Universitario la Paz, Madrid, Spain.

Purpose: Controversy persists regarding the amount of deformity that can be accepted before considering surgery for proximal

humerus fractures. The purpose of this study was to determine the effect of initial fracture pattern and displacement on the outcome of proximal humerus fractures treated non-operatively.

Material and Methods: Ninety-three consecutive patients treated non-operatively after sustaining a proximal humerus fracture were followed prospectively for one year. Results were rated using the ASES score, Neer rating system, and the DASH and SF-36 questionnaires. Radiographs and CT scans with 3-D reconstruction were obtained at the time of fracture and at one year for all patients. Displacement of individual fragments was measured with dedicated software on digitized images corrected for  magnification, and initial displacement was correlated with final outcome.

Results: Non-operative treatment resulted in an unsatisfactory Neer rating and/or loss of 10 or more points in the DASH score in 25% of the shoulders. There were 2 nonunions and 6 cases of AVN. 93% of the fractures belonged to one of four patters: posteromedial (varus) impaction (54%), lateral (valgus) impaction (14%), isolated greater tuberosity (16%), and anteromedial impaction (9%). Posteromedial impaction fractures, poorer outcomes were noted with more than 30 degrees of varus. In lateral impaction fractures, poorer outcomes were noted with angular head displacement over 25 degrees. Displacement of the greater tuberosity over 10 mm correlated with worse outcomes for both fracture types.Lateral impaction fractures had worse outcomes.

Conclusion: Most proximal humerus fractures follow predictable patters with a continuous spectrum of displacement. Head and tuberosity displacement strongly correlate with outcome. Measurements of fracture displacement on plain radiographs and CT scans may be used to predict outcome.