title: Quantification of the exposure of the glenohumeral joint from the minimally invasive to more invasive subscapularis approach to the anterior shoulder: a cadaveric study.
abstract: BACKGROUND
  There are multiple techniques to approach the glenohumeral joint. Our purpose was to quantify the average area of the glenohumeral joint exposed with 3 subscapularis approaches and determine the least invasive approach for placement of shoulder resurfacing and total shoulder arthroplasty instruments.
  
  
  METHODS
  Ten forequarter cadaveric specimens were used. Subscapularis approaches were performed sequentially from split, partial tenotomy, and full tenotomy through the deltopectoral approach. Glenohumeral joint digital photographs were analyzed in Image J software (National Institutes of Health, Bethesda, MD, USA). Shoulder resurfacing and total shoulder arthroplasty instruments were placed on the humeral head, and anatomic landmarks were identified.
  
  
  RESULTS
  The average area of humeral head visible, from the least to the most invasive approach, was 3.2, 8.1, and 11.0 cm2, respectively. The average area of humeral head visible differed significantly according to the approach. Humeral head area increased 157% when the subscapularis split approach was compared with the partial tenotomy approach and 35% when the partial approach was compared with the full tenotomy approach. The average area of glenoid exposed from least to most invasive approach was 2.0, 2.3, and 2.5 cm2, respectively. No significant difference was found between the average area of the glenoid and the type of approach. Posterior structures were difficult to visualize for the subscapularis split approach. Partial tenotomy of the subscapularis allowed placement of resurfacing in 70% of the specimens and total arthroplasty instruments in 90%.
  
  
  CONCLUSIONS
  The subscapularis splitting approach allows adequate exposure for glenoid-based procedures, and the subscapularis approaches presented expose the glenohumeral joint in a step-wise manner.
  
  
  METHODS
  Anatomy study, cadaver dissection.
authors.affiliation: Department of Orthopaedics & Rehabilitation, San Antonio Military Medical Center, Fort Sam Houston, TX, USA. Electronic address: jaime.l.bellamy.mil@mail.mil.
authors.forename: Jaime L
authors.initials: JL
authors.lastname: Bellamy
authors.affiliation: Department of Orthopaedics & Rehabilitation, San Antonio Military Medical Center, Fort Sam Houston, TX, USA.
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Johnson
authors.affiliation: Department of Orthopaedics & Rehabilitation, San Antonio Military Medical Center, Fort Sam Houston, TX, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Beltran
authors.affiliation: Orthopaedic Trauma Service, United States Army Institute of Surgical Research, Fort Sam Houston, TX, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Hsu
authors.affiliation: Orthopaedic Trauma Service, United States Army Institute of Surgical Research, Fort Sam Houston, TX, USA.
authors.lastname: Skeletal Trauma Research Consortium STReC
mesh_terms: D000328:Adult; D000368:Aged; D019643:Arthroplasty, Replacement / Q000295:instrumentation / Q000379:methods*; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D018482:Muscle, Skeletal / Q000601:surgery; D012782:Shoulder / Q000601:surgery; D012785:Shoulder Joint / Q000601:surgery*; D014481:United States
keywords: Glenohumeral joint; cadaver; full tenotomy; partial tenotomy; shoulder resurfacing; subscapularis split; total shoulder arthroplasty