title: The use of the impingement test as a predictor of outcome following subacromial decompression for rotator cuff tendinosis.
abstract: OBJECTIVE
  To evaluate the use of the impingement test as a predictor of outcome following subacromial decompression for patients with rotator cuff tendinosis.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  An impingement test was administered to each patient immediately before surgery. Patients underwent a subacromial decompression and were assessed postoperatively at 3 and 6 months. The primary outcome measure was the Western Ontario Rotator Cuff Index (WORC).
  
  
  RESULTS
  Thirty patients (mean age, 47.0 years; range, 29.4 to 71.2 years) took part in this study. There was no significant correlation between the classic impingement test (Neer's impingement sign before and after subacromial injection of local anesthetic) and the change in WORC score (r = -.174, P =.358). Similar results were obtained for the aggregate impingement test (pain at rest plus Neer's impingement sign plus Hawkins sign plus resisted abduction) before and after subacromial injection of local anesthetic (r = -.208, P =.270). When divided into categories of improvement following the classic impingement test (worse 0%-25%, 26%-50%, 51%-75%, 76%-100% better), there was no significant difference between groups for outcome as indicated by WORC score (P =.203). Results were similar for the aggregate impingement test (P =.271).
  
  
  CONCLUSIONS
  The impingement test is a poor tool for predicting the success of subacromial decompression. There are 6 assumptions discussed that must hold true in order for the impingement test to be a useful predictor of outcome following subacromial decompression. If one or more of these assumptions are not met, or are only partially met, the impingement test would be rendered invalid as a predictor of outcome, as this study suggests.
authors.affiliation: Fowler. Kennedy Sport Medicine Clinic, University of Western Ontario, London, Ontario, Canada. akirkley@julian.uwo.ca
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kirkley
authors.forename: Robert B
authors.initials: RB
authors.lastname: Litchfield
authors.forename: Dianne M
authors.initials: DM
authors.lastname: Jackowski
authors.forename: Ian K
authors.initials: IK
authors.lastname: Lo
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010808:Physical Examination / Q000379:methods*; D011446:Prospective Studies; D011788:Quality of Life; D017006:Rotator Cuff / Q000601:surgery*; D011795:Surveys and Questionnaires; D052256:Tendinopathy / Q000601:surgery*; D017211:Treatment Failure; D016896:Treatment Outcome