Scapular neck length and implications for reverse total shoulder arthroplasty: An anatomic study of 442 cadaveric specimens.
OBJECTIVE
Reverse total shoulder arthroplasty (RTSA) may be used to treat a variety of pathologic shoulder conditions, but complications such as scapular notching continue raise concerns. Variable anatomy surrounding the glenoid may have implications for future RTSA design, but at present the anatomy of the scapular neck in the human population has not been clearly defined.


METHODS
442 human scapulae from the Hamann-Todd Osteological Collection were measured for scapular neck length (SNL) and scapular neck angle (SNA). SNL was defined as the distance from the most lateral portion of the infraglenoid tubercle to the most inferolateral portion of the glenoid fossa. The SNA was measured according to Gerber et al. previously. The mean, standard deviation and ranges for SNL and SNA were calculated and compared based on sex and race, and interobserver variability was calculated.


RESULTS
The mean SNL was 1.06 cm ± 0.33 cm (0.37-2.43 cm). Males demonstrated a larger SNL (1.08 cm ± 0.33 cm) than females (1.01 cm ± 0.32 cm) (P < 0.12), and Caucasians (1.09 cm ± 0.33 cm) demonstrated a significantly larger SNL than African-Americans (1.00 cm ± 0.32) (P < 0.01). The mean SNA was 106.7° ± 11.0° (76.9-139.4°). No significant correlation was found between SNL and SNA (Pearson Correlation Coefficient = 0.018) (P < 0.702).


CONCLUSIONS
Scapular neck length and SNA vary widely within the population but there appears to be a tendency towards increased SNL in males and Caucasians.


CONCLUSIONS
The anatomy of the scapular neck may have significant implications for RTSA design, surgical planning, and reduction of associated complications.
The Cleveland Shoulder Institute, Department of Orthopaedics, University Hospitals of Cleveland, Cleveland, OH 44024, USA.
Chad M
CM
Fortun
The Cleveland Shoulder Institute, Department of Orthopaedics, University Hospitals of Cleveland, Cleveland, OH 44024, USA.
Jonathan J
JJ
Streit
The Cleveland Shoulder Institute, Department of Orthopaedics, University Hospitals of Cleveland, Cleveland, OH 44024, USA.
Steven A
SA
Horton
Department of Orthopedics, Henry Ford Hospital, Detroit, MI 48202, USA.
Stephanie J
SJ
Muh
The Cleveland Shoulder Institute, Department of Orthopaedics, University Hospitals of Cleveland, Cleveland, OH 44024, USA.
Robert J
RJ
Gillespie
The Cleveland Shoulder Institute, Department of Orthopaedics, University Hospitals of Cleveland, Cleveland, OH 44024, USA.
Reuben
R
Gobezie
Notching; reverse total shoulder arthroplasty; scapular neck angle; scapular neck length