Background: The aim was to evaluate if concomitant injury to the rotator cuff is important for functional outcome in proximal humerus fractures, and to relate loss of function to malunion of the fractures.
Materials and methods: A total of 76 patients treated conservatively for proximal humerus fracture were included in this cohort study. Performing an MRI: examination at the time of injury and after 12 months, tears of the rotator cuffs were classified as partial- or full thickness. The fractures were classified, according to the AO classification, and the degree of tubercle displacement and humeral head inclination evaluated at 12 months. Constant score was used as outcome measure.
Results: Magnetic resonance imaging (MRI) examinations confirmed 22 rotator cuff tears (four full thicknesses) diagnosed at the time of injury, and 10 additional tears (three full thicknesses) at one year. Functional loss at one year significantly corresponded to the tears at the time of injury (P = 0.004), varus malunion of the head and displacement of tubercles (P < 0.001).
Interpretation: Partial- as well as full thickness tears of the rotator cuff are important for functional outcome. Skeletal deterioration seems even more important.