title: Biomechanical comparison of lesser tuberosity osteotomy versus subscapularis tenotomy in total shoulder arthroplasty.
abstract: BACKGROUND
  Total shoulder arthroplasty is traditionally performed through an anterior deltopectoral exposure with subscapularis tenotomy. Postoperative subscapularis dysfunction is common and adversely affects clinical outcomes. Consequently, surgeon interest in lesser tuberosity osteotomy has grown in an effort to improve subscapularis repair strength. This study investigated the biomechanical strength of subscapularis tenotomy vs lesser tuberosity osteotomy in the setting of total shoulder arthroplasty.
  
  
  METHODS
  Uncemented humeral prostheses were placed in 20 paired upper extremities from 10 cadavers. For each respective cadaver, 1 limb underwent lesser tuberosity osteotomy and the contralateral limb underwent subscapularis tenotomy. The cadaveric specimens then underwent cyclic displacement and maximum load to failure testing.
  
  
  RESULTS
  The subscapularis tenotomy specimens exhibited significantly less cyclic displacement (0.8 mm) than the osteotomy group (1.8 mm), with a 95% confidence interval (CI) for the difference of 0.5 to 1.5 mm (P = 0.002). The maximum load to failure was 439 ± 96 N for tenotomy and 447 ± 89 N for osteotomy (95% CI for the difference of -58 to 75), which was not significant (P = .78).
  
  
  CONCLUSIONS
  Lesser tuberosity osteotomy was not significantly stronger than subscapularis tenotomy in maximum load to failure testing, with minimal clinical significance set at 100 N. Subscapularis tenotomy repair showed statistically significant less cyclic displacement than lesser tuberosity osteotomy. Further research is needed to clarify how the biomechanical results immediately after subscapularis tenotomy and lesser tuberosity osteotomy correlate with clinical outcomes.
authors: Department of Orthopedics, Mayo Clinic, Rochester, MN, USA.
authors: Steven A
authors: SA
authors: Giuseffi
authors: Prasit
authors: P
authors: Wongtriratanachai
authors: Hiromichi
authors: H
authors: Omae
authors: Akin
authors: A
authors: Cil
authors: Mark E
authors: ME
authors: Zobitz
authors: Kai-Nan
authors: KN
authors: An
authors: John W
authors: JW
authors: Sperling
authors: Scott P
authors: SP
authors: Steinmann
mesh_terms: D000368:Aged; D019643:Arthroplasty, Replacement / Q000379:methods*; D001696:Biomechanical Phenomena; D002102:Cadaver; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D006811:Humerus / Q000601:surgery*; D008297:Male; D010027:Osteotomy / Q000379:methods*; D016059:Range of Motion, Articular / Q000502:physiology; D017006:Rotator Cuff / Q000601:surgery; D012680:Sensitivity and Specificity; D012785:Shoulder Joint / Q000601:surgery*; D058971:Tenotomy / Q000379:methods*