title: Shoulder position increases ulnar nerve strain at the elbow of patients with cubital tunnel syndrome.
abstract: BACKGROUND
  Previous studies have shown that the shoulder internal rotation elbow flexion (SIREF) test, which is a modified elbow flexion (EF) test, has significantly higher sensitivity than the EF test in patients with cubital tunnel syndrome (CubTS). Here, we hypothesized that this increase in sensitivity was due to increase in the ulnar nerve strain around the elbow introduced by the additional shoulder position.
  
  
  METHODS
  Ulnar nerve strain at the elbow was intraoperatively measured at both the EF test and SIREF test positions in 20 patients with CubTS before simple decompression. Statistical analysis was performed with the Wilcoxon signed rank test at a confidence level of 99% (P < .001).
  
  
  RESULTS
  Mean ulnar nerve strain in the EF test position was 18.9% ± 12.1%, whereas that in the SIREF test position was 24.7% ± 14.0%. Ulnar nerve strain was higher in the SIREF than in the EF test position in all cases, and the difference was significant (mean, 5.8% ± 0.9%; 95% confidence interval, 3.90%-7.73%).
  
  
  CONCLUSIONS
  This study indicated that increased sensitivity in the SIREF test compared with the EF test was due to the increase in ulnar nerve strain around the elbow. To the best of our knowledge, this is the first study showing that shoulder position changes the ulnar nerve strain around the elbow in living patients with CubTS.
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, Tokyo, Japan; Department of Orthopaedic Surgery, Kawasaki Municipal Kawasaki Hospital, Kawasaki, Kanagawa, Japan; Department of Orthopaedic Surgery, Institute of Rheumatology, Tokyo Women's Medical University, Shinjuku, Tokyo, Japan. Electronic address: ochi@1998.jukuin.keio.ac.jp.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Ochi
authors.affiliation: Department of Orthopaedic Surgery, Kawasaki Municipal Kawasaki Hospital, Kawasaki, Kanagawa, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Horiuchi
authors.affiliation: Department of Orthopaedic Surgery, Kawasaki Municipal Kawasaki Hospital, Kawasaki, Kanagawa, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Horiuchi
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, Tokyo, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Iwamoto
authors.affiliation: Department of Orthopaedic Surgery, National Hospital Organization Saitama Hospital, Wako, Saitama, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Morisawa
authors.affiliation: Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, Tokyo, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Sato
mesh_terms: D000328:Adult; D000368:Aged; D020430:Cubital Tunnel Syndrome / Q000503:physiopathology* / Q000601:surgery; D019299:Decompression, Surgical; D004550:Elbow / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010808:Physical Examination; D011187:Posture; D016059:Range of Motion, Articular; D012399:Rotation; D012785:Shoulder Joint / Q000503:physiopathology*; D013180:Sprains and Strains / Q000503:physiopathology* / Q000601:surgery; D014459:Ulnar Nerve / Q000503:physiopathology* / Q000601:surgery
keywords: Cubital tunnel syndrome; elbow flexion test; nerve strain; shoulder abduction; shoulder internal rotation; shoulder internal rotation elbow flexion test; ulnar nerve palsy; ulnar neuropathy