title: Risk Factors for Ulnar Nerve Instability Resulting in Transposition in Patients With Cubital Tunnel Syndrome.
abstract: OBJECTIVE
  To assess the incidence of ulnar nerve instability in patients undergoing in situ decompression and to identify preoperative risk factors to predict the need for transposition.
  
  
  METHODS
  Using our surgical database, we retrospectively identified 363 patients who were candidates for in situ ulnar nerve decompression for the treatment of cubital tunnel syndrome over a 5-year period. During this time, the 3 participating surgeons considered ulnar nerve instability to be a contraindication for in situ ulnar nerve decompression. We collected demographic data including sex, age, weight, height, and body mass index. We recorded the number of patients who underwent ulnar nerve transposition owing to ulnar nerve instability and evaluated whether ulnar nerve instability was diagnosed before, during, or after surgery.
  
  
  RESULTS
  Of the 363 patients who were considered for in situ ulnar nerve decompression, 76 patients (21%) underwent ulnar nerve transposition secondary to ulnar nerve instability. Twenty-nine patients (8%) were identified with instability before surgery, and 44 patients (12%) were identified with instability during surgery following in situ decompression. Three patients (1%) were not diagnosed with instability until after surgery and subsequently underwent secondary transposition. Patients who underwent transposition owing to instability were more likely to be male and to be younger.
  
  
  CONCLUSIONS
  A notable percentage of patients with a stable nerve before surgery will have ulnar nerve instability following decompression. Identification of factors correlating to instability and the potential need for transposition can aid surgeons and patients in preoperative planning.
authors.affiliation: Rothman Institute, Thomas Jefferson University, Philadelphia, PA. Electronic address: jonas.matzon@rothmaninstitute.com.
authors.forename: Jonas L
authors.initials: JL
authors.lastname: Matzon
authors.affiliation: Rothman Institute, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Lutsky
authors.affiliation: Rothman Institute, Thomas Jefferson University, Philadelphia, PA.
authors.forename: C Edward
authors.initials: CE
authors.lastname: Hoffler
authors.affiliation: Rothman Institute, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Nayoung
authors.initials: N
authors.lastname: Kim
authors.affiliation: Rothman Institute, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Maltenfort
authors.affiliation: Rothman Institute, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Pedro K
authors.initials: PK
authors.lastname: Beredjiklian
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D020430:Cubital Tunnel Syndrome / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016067:Nerve Transfer; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D014459:Ulnar Nerve / Q000601:surgery*; D020424:Ulnar Neuropathies / Q000209:etiology*; D055815:Young Adult
keywords: Cubital tunnel syndrome; ulnar nerve decompression; ulnar nerve instability; ulnar nerve transposition