Tuberosity position correlates with fatty infiltration of the rotator cuff after hemiarthroplasty for proximal humeral fractures.

HYPOTHESIS: This study investigates the correlation between tuberosity positioning, fatty infiltration of the rotator cuff, and clinical outcome after hemiarthroplasty for proximal humeral fracture.

MATERIALS AND METHODS: Twenty patients with a mean age of 70.8 +/- 9.9 years were evaluated at a mean of 19.8 +/- 9.4 months. Evaluation included assessment of the Constant score (CS); Disabilities of the Arm, Shoulder and Hand (DASH) score; radiographic evaluation; and computed tomography to classify healing of the tuberosities and changes in the rotator cuff. Fatty degeneration of the cuff was classified according to the Goutallier classification as stage 0 to 4. Tuberosity positioning was classified as mal-positioning of less than 0.5 cm., 0.5 to 1 cm., >1.0 cm., or not healed.

RESULTS: The mean Constant Score (CS) of patients with greater tuberosity displacement of <0.5 cm was significantly higher than the CS of patients with > or =0.5 cm displacement and non-united greater tuberosities. The CS of patients with greater tuberosity displacement of 0.5 to 1 cm was significantly higher than that in patients with non-united greater tuberosities. For the lesser tuberosity, patients with displacement of <0.5 cm showed significantly higher outcome scores than patients with displacement of >1 cm and non-united lesser tuberosities. There was a significant correlation between fatty infiltration of the supraspinatus and infraspinatus muscles and greater tuberosity malposition and between fatty infiltration of the subscapularis and lesser tuberosity malposition.

CONCLUSION: Fatty infiltration of the cuff was significantly associated with lower clinical scores. Tuberosity positioning and healing are critical for improved clinical outcomes after hemiarthroplasty for proximal humeral fractures.