title: Hip Arthroscopy for Atypical Posterior Hip Pain: A Comparative Matched-Pair Analysis.
abstract: BACKGROUND
  Femoroacetabular impingement (FAI) most commonly manifests as anterior groin pain. Patients occasionally have posterior pain but otherwise have clinical and radiographic evidence of FAI.
  
  
  OBJECTIVE
  To compare outcomes of hip arthroscopy for FAI in patients with atypical posterior pain versus a matched group with the typical anterior pain presentation.
  
  
  METHODS
  Cohort study; Level of evidence, 3.
  
  
  METHODS
  Patients undergoing primary hip arthroscopy for FAI were identified from a clinical repository between January 2012 and 2014. Of 503 patients during the study period, 31 (6.2%) had posterior hip or buttock pain reproduced with flexion, adduction, and internal rotation (FADDIR) and were classified as "atypical," while those with anterior hip or groin pain were classified as "typical." Atypical patients were matched in a 1:2 cohort to the typical group based on sex, age, and body mass index (BMI). Postoperative patient-reported outcomes included visual analog scale (VAS) for pain, modified Harris Hip Score (mHHS), and Hip Outcome Scores with Activities of Daily Living (HOS-ADL) and Sports-Specific (HOS-SS) subscales.
  
  
  RESULTS
  Of the 31 atypical patients, 28 (90.3%) were available for a minimum 2-year follow-up (mean ± SD, 2.6 ± 0.6 years). These patients were matched with 56 typical patients. No differences were noted between typical and atypical cohorts in preoperative demographic or radiographic parameters. Postoperatively, both groups demonstrated significant improvements in mHHS (atypical 60.1 ± 12.4 to 78.8 ± 12.9; typical 60.0 ± 12.3 to 76.9 ± 13.6; P < .001), HOS-ADL (atypical 68.5 ± 17.0 to 88.6 ± 11.0; typical 69.2 ± 17.1 to 86.8 ± 14.7; P < .001), and HOS-SS (atypical 42.0 ± 25.5 to 71.0 ± 26.2; typical 44.4 ± 24.9 to 71.3 ± 27.3; P < .001). No differences were found in 2-year score improvements between the atypical and typical cohorts (mHHS 18.7 ± 13.4 vs 16.9 ± 13.1, P = .48; HOS-ADL 20.1 ± 16.8 vs 17.6 ± 14.6, P = .19; HOS-SS 29.0 ± 30.2 vs 26.9 ± 27.3, P = .93). Also, no significant differences were found in VAS pain improvement (5.0 ± 3.2 vs 5.6 ± 2.8, P = .56) or postoperative satisfaction (79.5 ± 5.5 vs 77.5 ± 4.1, P = .78).
  
  
  CONCLUSIONS
  Atypical posterior hip pain is an uncommon presentation of FAI. Patients demonstrate similar significant improvements after hip arthroscopy in outcome scores, postoperative pain, and satisfaction compared with patients who have classic anterior groin pain.
authors.affiliation: Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Levy
authors.affiliation: Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Cvetanovich
authors.affiliation: Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Kuhns
authors.affiliation: Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Mitchell J
authors.initials: MJ
authors.lastname: Greenberg
authors.affiliation: Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Alter
authors.affiliation: Department of Orthopedic Surgery, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Shane J
authors.initials: SJ
authors.lastname: Nho
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D018771:Arthralgia / Q000209:etiology / Q000517:prevention & control / Q000601:surgery*; D001182:Arthroscopy; D015331:Cohort Studies; D005260:Female; D057925:Femoracetabular Impingement / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D006621:Hip Joint / Q000601:surgery; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D010147:Pain Measurement; D011859:Radiography; D016059:Range of Motion, Articular; D016896:Treatment Outcome; D064232:Visual Analog Scale
keywords: anterior groin pain; atypical hip pain; femoroacetabular impingement; hip arthroscopy; posterior hip pain