title: Knot impingement after rotator cuff repair: is it real?
abstract: OBJECTIVE
  The purpose of this study was to compare morphologic features of the acromion after 2 different repair methods (single-row [SR] repair with a minimum of 4 knots and suture-bridge [SB] repair with minimal knots) in medium to large rotator cuff tears.
  
  
  METHODS
  From May 2005 to July 2012, 1,693 rotator cuff repairs were performed, among them medium to large tears requiring more than 2 anchors for repair; those who had 6-month postoperative magnetic resonance imaging (MRI) scans were included (221 shoulders). They were divided into 2 groups; group A (SR repair) and group B (SB repair). Acromial morphologic characteristics were evaluated using MRI 6 months postoperatively. An acromial defect was defined as an irregular defect or erosion on the flat acromion. Clinical measurements were performed using the American Shoulder and Elbow Surgeons (ASES) score, Constant score, visual analogue scale (VAS) pain score, and range of motion (ROM).
  
  
  RESULTS
  Erosion in the acromion was observed in 2 of 118 patients (1.7%) in group A and in 1 of 103 (1%) patients in group B. There was no statistically significant difference between the 2 groups (P = .796). A statistically significant improvement was observed in the clinical scores measured (P = .0043). ROM was not fully recovered to the preoperative level at 6 months postoperatively. Acromioplasty was performed in 2 of 3 patients with acromial erosion. There was acromial erosion in one patient in group A without performing subacromial decompression.
  
  
  CONCLUSIONS
  Our study showed that there was no difference in acromial erosion in high-profile knots made by an SR compared with double-row (DR) SB low-profile repairs.
  
  
  METHODS
  Level III, retrospective comparative study.
authors.affiliation: Department of Orthopaedic Surgery, Samsung Medical Center, Sungkyunkwan University, Seoul, Korea.
authors.forename: Young Eun
authors.initials: YE
authors.lastname: Park
authors.affiliation: Department of Orthopaedic Surgery, National Medical Center, Seoul, Korea.
authors.forename: Min Soo
authors.initials: MS
authors.lastname: Shon
authors.affiliation: Department of Orthopaedic Surgery, Wonkwang University Sanbon Hospital, Gyeonggi-do, Korea.
authors.forename: Tae Kang
authors.initials: TK
authors.lastname: Lim
authors.affiliation: Department of Orthopaedic Surgery, Seoul Medical Center, Seoul, Korea.
authors.forename: Kyoung Hwan
authors.initials: KH
authors.lastname: Koh
authors.affiliation: Department of Orthopaedic Surgery, Samsung Medical Center, Sungkyunkwan University, Gyeongsangnam-do, Korea.
authors.forename: Sung-Weon
authors.initials: SW
authors.lastname: Jung
authors.affiliation: Department of Orthopaedic Surgery, Samsung Medical Center, Sungkyunkwan University, Seoul, Korea. Electronic address: shoulderyoo@gmail.com.
authors.forename: Jae Chul
authors.initials: JC
authors.lastname: Yoo
mesh_terms: D000174:Acromion / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D001178:Arthroplasty; D001182:Arthroscopy / Q000009:adverse effects / Q000379:methods*; D019299:Decompression, Surgical; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D017006:Rotator Cuff / Q000601:surgery; D000070636:Rotator Cuff Injuries; D012421:Rupture / Q000601:surgery; D053441:Suture Anchors; D013536:Suture Techniques; D013537:Sutures / Q000009:adverse effects*; D016896:Treatment Outcome; D014945:Wound Healing