title: Pectoralis minor tendon in the rotator interval: arthroscopic, magnetic resonance imaging findings, and clinical significance.
abstract: BACKGROUND
  Although insertional variation of the pectoralis minor on the rotator interval has been reported, more detailed characteristics as seen on magnetic resonance imaging (MRI) or arthroscopy and clinical significance have been rarely discussed. This study evaluated the prevalence of tendinous insertion of the pectoralis minor by arthroscopy and diagnostic performances of MRI and suggests its clinical implication in rotator cuff repair.
  
  
  METHODS
  The study prospectively recruited 99 consecutive patients for arthroscopic exploration of pectoralis minor insertion. Preoperative MRIs were evaluated to detect tendinous insertion of the pectoralis minor by 2 independent, blinded observers, and these results were correlated with arthroscopy as the gold standard. During arthroscopy, the effect of this variation on supraspinatus tendon tear and repair was evaluated.
  
  
  RESULTS
  Tendinous insertion of the pectoralis minor was found in 11 patients (11%) at arthroscopy. The sensitivity and specificity of MRI were 64% (95% confidence interval [CI], 31%-89%), the specificity was 82% (95% CI, 72%-89%), and the accuracy was 80% (95% CI, 72%-88%). Intraobserver and interobserver reliability tests showed moderate agreements. In 7 patients, it tethered the retracted supraspinatus tendon from mobilization and gave rise to tension on the repaired cuff, which warranted complete resection of the pectoralis minor tendon for a tension-free cuff repair.
  
  
  CONCLUSIONS
  Tendinous insertion of the pectoralis minor existed with 11% prevalence in our series and could be preoperatively detected on MRI. During arthroscopic rotator cuff repair, it can be an obstacle to supraspinatus tendon mobilization and repair.
authors.affiliation: Department of Orthopaedic Surgery, Eulji Hospital, Eulji University School of Medicine, Seoul, South Korea.
authors.forename: Tae Kang
authors.initials: TK
authors.lastname: Lim
authors.affiliation: Department of Orthopaedic Surgery, Ilsan-Paik Hospital, Inje University School of Medicine, Seoul, South Korea.
authors.forename: Kyoung Hwan
authors.initials: KH
authors.lastname: Koh
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Young Cheol
authors.initials: YC
authors.lastname: Yoon
authors.affiliation: Department of Orthopaedic Surgery, Eulji Hospital, Eulji University School of Medicine, Seoul, South Korea.
authors.forename: Jae Hyun
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Orthopaedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea. Electronic address: shoulderyoo@gmail.com.
authors.forename: Jae Chul
authors.initials: JC
authors.lastname: Yoo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001182:Arthroscopy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010369:Pectoralis Muscles / Q000002:abnormalities*; D011446:Prospective Studies; D015203:Reproducibility of Results; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D012680:Sensitivity and Specificity; D013710:Tendons / Q000002:abnormalities*; D014945:Wound Healing
keywords: Pectoralis minor; rotator interval; tendinous insertion