title: Shoulder stiffness after rotator cuff repair: risk factors and influence on outcome.
abstract: OBJECTIVE
  The aims of this study were to determine the incidence of postoperative stiffness after rotator cuff repair and to evaluate postoperative stiffness with respect to its risk factors and its influence on outcome.
  
  
  METHODS
  We included 288 patients (mean age, 59.5 ± 8.4 years) who underwent surgical repair of full-thickness rotator cuff tears. Postoperative range of motion was measured serially 3 months, 6 months, and at least 1 year (mean, 22.8 ± 13.1 months) after surgery. Simultaneously, functional outcome was evaluated using the pain visual analog scale (VAS) and the American Shoulder and Elbow Surgeons (ASES) score, and cuff healing was confirmed by computed tomography arthrography or ultrasonography at least 1 year after surgery (mean, 13.5 ± 2.7 months). We calculated the serial incidence of postoperative stiffness at each follow-up visit, assessed the risk factors for postoperative stiffness at each period, and then evaluated the correlation of stiffness with cuff healing and functional outcome.
  
  
  RESULTS
  The incidence of postoperative stiffness was 18.6% (54/288) at 3 months, 2.8% (8/288) at 6 months, and 6.6% (19/288) at final follow-up. Mean age was higher in the stiffness group at all times (all P < .05). Preoperative stiffness affected postoperative stiffness only at 3 months (P = .04). Larger tear size, higher grade of fatty infiltration (FI), and open or mini-open surgery were correlated with stiffness only at final follow-up (all P < .05). More patients with final postoperative stiffness showed retear (17/19, 89.5%) compared with those without stiffness (49/269, 18.2%, P < .001), and retear was an independent factor for late postoperative stiffness. Pain VAS was higher in the stiffness group at 3 months and final follow-up (all P < .01), and ASES score was lower in the stiffness group only at final follow-up (P = .03).
  
  
  CONCLUSIONS
  Old age is an important risk factor for postoperative stiffness throughout the follow-up period. Early postoperative stiffness is affected by preoperative stiffness. However, late postoperative stiffness, especially newly developed stiffness, is closely related to retear and significantly worse functional outcome after surgical repair, even though we could not find the cause-effect relation. When a patient complains about newly developed stiffness in the late postoperative period, retear should be considered.
  
  
  METHODS
  Level IV, therapeutic case series.
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam-si, Korea.
authors.forename: Seok Won
authors.initials: SW
authors.lastname: Chung
authors.forename: Cao Ba
authors.initials: CB
authors.lastname: Huong
authors.forename: Sae Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Joo Han
authors.initials: JH
authors.lastname: Oh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D020127:Recovery of Function; D012307:Risk Factors; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D012782:Shoulder / Q000601:surgery*; D013708:Tendon Injuries / Q000534:rehabilitation* / Q000601:surgery; D016896:Treatment Outcome