A Study of Biomechanics of Dislocating Hips and Asymptomatic Non-dislocating Hips


  • Study type

  • Study IDs

  • Describes the nature of a clinical study. Types include:

    • Observational study — observes people and measures outcomes without affecting results.
    • Interventional study (clinical trial) — studies new tests, treatments, drugs, surgical procedures or devices.
    • Medical records research — uses historical information collected from medical records of large groups of people to study how diseases progress and which treatments and surgeries work best.
  • Site IRB
    • Rochester, Minnesota: 17-008412
    Sponsor Protocol Number: CSP2017-02

About this study

The primary objective of this study is to determine whether the functional cup orientation for dislocating hips differs from the functional cup orientation for asymptomatic non-dislocating hips.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. If you need assistance understanding the eligibility criteria, please contact the study team.

See eligibility criteria

Inclusion Criteria:

  • Patients who understand the conditions of the study and are willing to participate in a single two-hour visit to the clinical site.
  • Patients who are male and female, 30 years of age or older.
  • Patients with a pre-primary THR diagnosis of osteoarthritis or avascular necrosis.
  • Patients with a 32mm or 36mm diameter THR bearing.
  • For Group 1, Patients who have had a single or first episode of dislocation beyond 6 weeks following their primary THR.
  • For Group 1, Patients who have had a single episode or multiple episodes of dislocation following their primary THR, but have not been revised.
  • For the Group 2, Patients who are beyond 1 year post-operative following their primary THR and have had no incidence of hip dislocation following their primary THR.
  • For the Group 2, Patients who are asymptomatic based upon their pain, feeling of "popping out", and range of motion in the primary THR hip.
  • Patients who have been deemed eligible for the study as determined by a blinded radiograph reviewer.
  • Patients who have consented to participate in the study.

Exclusion Criteria:

  • Patients who aren’t able to clearly describe the activity in which their dislocation occurred (applicable to "dislocator group").
  • Patients with a lipped polyethylene liner.
  • Patients who are reluctant to flex as far forward as possible during the seated x-ray with their legs abducted.
  • Patients with abductor insufficiency.
  • Patients whose index hip is short by >5mm, or have offset reduced by >10mm in comparison to the contralateral side as measured on radiographs.
  • For the Group 1, Patients who had a spinal fusion or spinal surgery post-dislocation.
  • For the Group 2, Patients with evidence of hip joint instability (e.g., pain, feeling of "popping out", and limited range of motion, ball and socket joint laxity) of the joint.
  • Patients who have a neurological disorders which may interfere or adversely affect gait or weight bearing (e.g., Parkinson’s, muscular dystrophy, multiple sclerosis).
  • Patients who have cerebral dysfunction (e.g., stroke).
  • Patients who have a medical history of femoral neck fracture, hip fracture.
  • Patients who have a medical history of rheumatoid arthritis.
  • Patients who are a known drug or alcohol abuser, or have a psychological disorder.
  • Patients who are currently involved in any personal injury litigation, medical-legal or worker’s compensations claims.
  • Patients who are unable to provide informed consent.
  • Patients who are unable to comply with all the required study procedures.

FINAL EXCLUSIONS - following consent to participate in the study:

  • If the subject isn’t flexed enough in the picture taken by radiology to achieve the positioning specified in the Imaging Protocol, or if the subject answers to being "apprehensive" or "significantly apprehensive" in the flexed seated position on the Apprehension Questionnaire
  • A combined anteversion5 (CT measured supine cup anteversion + stem anteversion to the posterior condyles) that is outside of the range of 25 – 50.

Participating Mayo Clinic locations

Study statuses change often. Please contact us for help.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

David Lewallen, M.D.

Open for enrollment

Contact information:

Jonathan Furuseth




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