title: Interest of an intraoperative limb-length and offset measurement device in total hip arthroplasty.
abstract: BACKGROUND
  Total hip arthroplasty (THA) seeks to restore a stable, mobile and pain-free joint. This requires good implant positioning and peroperative restoration of limb-length and femoral offset.
  
  
  OBJECTIVE
  A mechanical measurement device (length and offset optimization device [LOOD]) fixed to the pelvis can optimize lower-limb length and offset control during THA performed on a posterolateral approach.
  
  
  METHODS
  Two prospective THA series were compared: 32 using the LOOD and 26 without. Patients with more than 5mm preoperative limb-length discrepancy were excluded. The intraoperative target was to restore individual anatomy. Radiographic analysis was based on pre- and postoperative AP pelvic weight-bearing views in upright posture, feet aligned, with comparison to peroperative LOOD data.
  
  
  RESULTS
  Mean deviation from target length (i.e., pre- to postoperative length differential) was 2.31 mm (range, 0.04-10.6mm) in patients operated on using the LOOD versus 6.96 mm (0.01-178 mm) without LOOD (P=0.0013). Mean deviation from target offset was 3.96 (0.45-13.50) mm with LOOD versus 10.16 (0.93-28.81) without (P=0.0199). There was no significant difference between operative and radiographic measurements of length deviation using LOOD (P=0.4); those for offset, however, differed significantly (P=0.02).
  
  
  CONCLUSIONS
  The LOOD guides control of limb-length and offset during THA on a posterolateral approach. Reliability seems to be better for limb-length than for offset. It is a simple and undemanding means of controlling limb-length and offset during THA.
  
  
  METHODS
  III, prospective case-control study.
authors.affiliation: Bégin Military Teaching Hospital, 69, avenue de Paris, 94160 Paris, France. Olive.barbier@gmail.com
authors.forename: O
authors.initials: O
authors.lastname: Barbier
authors.forename: D
authors.initials: D
authors.lastname: Ollat
authors.forename: G
authors.initials: G
authors.lastname: Versier
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D016022:Case-Control Studies; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D007430:Intraoperative Care; D007870:Leg Length Inequality / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D016896:Treatment Outcome