title: High preoperative range of motion is a significant risk factor for dislocation in primary total hip arthroplasty.
abstract: Dislocation after total hip arthroplasty (THA) is multifactorial and is dependent on surgical, implant, and patient factors. We hypothesized that high preoperative hip range of motion is an important variable contributing to instability after THA. We retrospectively reviewed 3379 THAs performed during a 21-year period. Average follow-up was 6.6 years. We examined the effect of surgical approach, femoral head size, and preoperative range of motion on dislocation rates. Patients with a posterior approach and 115 degrees or greater of combined preoperative flexion, adduction, and internal rotation dislocated at a significantly higher frequency than those with less than 115 degrees of combined motion (odds ratio, 1.9; P = .007). High preoperative motion in conjunction with a posterior approach and femoral head size less than 32 mm had the highest dislocation rate in our sample (5.9%). Preoperative range of motion is an important variable that should be taken into consideration during operative planning to help reduce the risk of dislocation.
authors.affiliation: Joint Replacement Surgeons of Indiana Research Foundation Center for Hip and Knee Surgery, Mooresville, Indiana 46158, USA.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Krenzel
authors.forename: Michael E
authors.initials: ME
authors.lastname: Berend
authors.forename: Robert A
authors.initials: RA
authors.lastname: Malinzak
authors.forename: Philip M
authors.initials: PM
authors.lastname: Faris
authors.forename: E Michael
authors.initials: EM
authors.lastname: Keating
authors.forename: John B
authors.initials: JB
authors.lastname: Meding
authors.forename: Merrill A
authors.initials: MA
authors.lastname: Ritter
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D005260:Female; D005500:Follow-Up Studies; D006617:Hip Dislocation / Q000453:epidemiology*; D006621:Hip Joint / Q000503:physiopathology* / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery; D057234:Preoperative Period; D011475:Prosthesis Failure; D016059:Range of Motion, Articular / Q000502:physiology*; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult