title: Delayed-onset ulnar neuritis after release of elbow contractures: clinical presentation, pathological findings, and treatment.
abstract: BACKGROUND
  Little information exists regarding delayed-onset ulnar neuritis (DOUN) after arthroscopic release of elbow contractures.
  
  
  OBJECTIVE
  To describe, in a large cohort of patients, the clinical presentation of and risk factors for developing DOUN after arthroscopic release of elbow contractures.
  
  
  METHODS
  Case-control study; Level of evidence, 3.
  
  
  METHODS
  A retrospective study of 565 consecutive arthroscopic releases of elbow contractures was conducted. Essentially, DOUN was defined as ulnar neuritis or neuropathy, or worsening of pre-existing ulnar nerve symptoms, that developed postoperatively in patients with normal neurological examination findings immediately after surgery. After inclusion and exclusion criteria were met, 235 contracture releases in patients who had not undergone any ulnar nerve surgery remained and were used for the analysis of risk factors with a multivariate logistic regression analysis.
  
  
  RESULTS
  Twenty-six patients (11%) developed DOUN. The patients fell into 1 of 3 distinct groups. Fifteen (58%) presented with rapidly progressive DOUN, characterized by rapidly progressive sensorimotor ulnar neuropathy, increasing pain at the cubital tunnel during end-range flexion and/or extension, and rapidly deteriorating range of motion within the first week after surgery. Urgent ulnar subcutaneous nerve transposition was performed within 1 or 2 days of diagnosis. Eight (31%) presented with nonprogressive DOUN, characterized by mild sensory ulnar neuropathy, neither motor weakness nor substantial pain at the cubital tunnel, or loss of motion. Three (12%) presented with slowly progressive DOUN, characterized by the insidious onset of mild ulnar neuropathy. Significant risk factors for DOUN included a diagnosis of heterotopic ossification (odds ratio, 31; 95% CI, 5-191; P < .001), preoperative neurological symptoms (odds ratio, 6; 95% CI, 2-19; P = .001), and preoperative arc of motion (odds ratio, 0.97 per degree of motion; 95% CI, 0.96-0.99; P = .02).
  
  
  CONCLUSIONS
  Delayed-onset ulnar neuritis is an important complication of arthroscopic release of elbow contractures. We recommend a high index of suspicion and monitoring patients with progressive loss of elbow motion and end-range pain for evidence of subclinical ulnar neuritis.
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA Department of Orthopaedics and Traumatology, University of Turin Medical School, Turin, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Blonna
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA Department of Orthopaedic Surgery, Penn Sports Medicine Center, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: G Russell
authors.initials: GR
authors.lastname: Huffmann
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA odriscoll.shawn@mayo.edu.
authors.forename: Shawn W
authors.initials: SW
authors.lastname: O'Driscoll
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001182:Arthroscopy / Q000009:adverse effects*; D016022:Case-Control Studies; D002648:Child; D003286:Contracture / Q000601:surgery*; D004551:Elbow Joint / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009999:Ossification, Heterotopic / Q000150:complications; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D012307:Risk Factors; D020424:Ulnar Neuropathies / Q000209:etiology* / Q000473:pathology
keywords: DOUN; delayed-onset ulnar neuritis; elbow contracture release