title: Reliability and clinical outcomes of preoperative evaluations in modern total hip resurfacing and total hip arthroplasty in patients with osteonecrosis of the femoral head.
abstract: BACKGROUND
  Modern total hip resurfacing has been associated with excellent intermediate outcome in patients with osteonecrosis hip who are under 60 years., Up to 30-50% necrosis area in X-ray and MRI are theoretically acceptable to perform total hip resurfacing. However, both of plain X-ray and MRI still are uncertain information to precisely support decision making for either hip resurfacing or hip arthroplasty.
  
  
  OBJECTIVE
  Double setup operations (resurfacing or arthroplasty) were developed (i) to evaluate the reliability of preoperative evaluation based on plain X-ray and MRI comparing to the intra-operative finding after the completion of bone surface cut in hip resurfacing femoral procedure and (ii) to examine the early outcome for this double set up techniques.
  
  
  METHODS
  Between September 2004 to December 2008, 45 osteonecrosis hips (40 patients) were managed with double setup in which was either total hip resurfacing or total hip arthroplasty. The final intraoperative decisions were performed and then the comparison of the reliability of pre-operative evaluation was done. Outcomes assessment was examined based on Harris Hip score, Oxford hip score, university of California Los Angeles (UCLA) activity score, Short form-12 score, complications, and radiographic alignment including radiolucencies.
  
  
  RESULTS
  Twenty-five hips finally were performed with total hip resurfacing and the rest twenty hips were performed with total hip arthroplasty. Preoperative evaluation plans were unchanged from arthroplasty to resurfacing by intra-operative evaluation in 20 of 33 hips, representing the approximate reliability 61%. All 13 cases whose preoperative plans were changed had preoperative radiographic necrotic head involvement more than 50%, cystic change > 1.5 cm in size, superior head collapse more than 8 mm. The follow-up mean time was 28.6 months (5-50). All postoperative functional scores at the last follow-up (HHS, Oxford, UCLA, SF12) were significantly improved from preoperative functional score (p < 0.001). Pulmonary embolism was found in one patient with sickle cells induced osteonecrosis hip and no further complication after recovery. There was no postoperative infection, fracture neck of femur, DVT, nerve palsy, radiographic change.
  
  
  CONCLUSIONS
  Double setup operations were found efficacious to provide reliable information for the resurfacing surgeons to avoiding the too early total hip arthroplasty in the young patients. As a result, the patients can preserve their femoral heads at best.
authors.affiliation: Department of Orthopedic Surgery, Police General Hospital, Bangkok, Thailand. virojlarb@gmail.com
authors.forename: Viroj
authors.initials: V
authors.lastname: Larbpaiboonpong
authors.forename: Thana
authors.initials: T
authors.lastname: Turajane
authors.forename: Thaworn
authors.initials: T
authors.lastname: Sisayanarane
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods*; D002140:California; D005260:Female; D005271:Femur Head Necrosis / Q000000981:diagnostic imaging / Q000601:surgery*; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011859:Radiography; D015203:Reproducibility of Results; D016896:Treatment Outcome