title: Traumatic posterior hip subluxation in American football.
abstract: BACKGROUND
  Traumatic posterior hip subluxation is a potentially devastating injury that is often misdiagnosed as a simple hip sprain or strain. The purpose of the present study was to outline the injury mechanism, pathoanatomy, clinical and radiographic findings, and treatment of traumatic hip subluxation in an athletic population.
  
  
  METHODS
  Over a nine-year period, eight participants in American football who had sustained a traumatic posterior hip subluxation were evaluated and treated. The injury mechanism, clinical findings, and radiographic findings were reviewed. The mean duration of follow-up was thirty-four months.
  
  
  RESULTS
  The most common mechanism of injury was a fall on a flexed, adducted hip. Physical examination revealed painful limitation of hip motion. Initial radiographs demonstrated a characteristic posterior acetabular lip fracture. Initial magnetic resonance images revealed disruption of the iliofemoral ligament, hemarthrosis, and a viable femoral head. Two players were treated acutely with hip aspiration, and all eight players were treated with a six-week regimen of toe-touch weight-bearing with use of crutches. Six players recovered and returned to the previous level of competition. Two players had development of severe osteonecrosis and ultimately required total hip arthroplasty.
  
  
  CONCLUSIONS
  The pathognomonic radiographic and magnetic resonance imaging triad of posterior acetabular lip fracture, iliofemoral ligament disruption, and hemarthrosis defines traumatic posterior hip subluxation. Patients in whom large hemarthroses are diagnosed on magnetic resonance images should undergo acute aspiration, and all players should be treated with a six-week regimen of toe-touch weight-bearing with use of crutches. Patients who have no sign of osteonecrosis on magnetic resonance imaging at six weeks can safely return to sports activity. Patients in whom osteonecrosis is diagnosed at six weeks are at risk for collapse and joint degeneration, and they should be advised against returning to sports.
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Claude T
authors.initials: CT
authors.lastname: Moorman
authors.forename: Russell F
authors.initials: RF
authors.lastname: Warren
authors.forename: Elliott B
authors.initials: EB
authors.lastname: Hershman
authors.forename: John F
authors.initials: JF
authors.lastname: Crowe
authors.forename: Hollis G
authors.initials: HG
authors.lastname: Potter
authors.forename: Ronnie
authors.initials: R
authors.lastname: Barnes
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: O'Brien
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Guettler
mesh_terms: D000058:Accidental Falls; D000293:Adolescent; D000328:Adult; D019644:Arthroplasty, Replacement, Hip; D001696:Biomechanical Phenomena; D003446:Crutches; D003937:Diagnosis, Differential; D005271:Femur Head Necrosis / Q000209:etiology / Q000601:surgery; D005500:Follow-Up Studies; D005538:Football / Q000293:injuries*; D006617:Hip Dislocation / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D006801:Humans; D008023:Ligaments, Articular / Q000293:injuries; D008279:Magnetic Resonance Imaging; D008297:Male; D010808:Physical Examination; D026741:Physical Therapy Modalities; D011379:Prognosis; D016059:Range of Motion, Articular; D012307:Risk Factors; D013396:Suction; D016896:Treatment Outcome; D014743:Videotape Recording; D016474:Weight-Bearing