A Comparison of Two Different Surgical Techniques in Hip Resurfacing Arthroplasty
Condition: Osteonecrosis; Femoral Neck Fracture; Implant Failure
MeSH terms: Osteonecrosis; Femoral Neck Fractures
Study type: Interventional

Summary: 
      The purpose of the study is to compare two different surgical techniques in hip resurfacing
      arthroplasty (RHA), comparing bloodflow and metabolism in the femoral head, as well as
      implant migration, periprosthetic bone mineral density, gait function and patient recovery.
    

Detailed description: 
      BACKGROUND:

      6700 total hip replacements are performed each year in Denmark due to osteoarthritis. Young
      patients sustain a substantial risk of early implant failure due to high-activity daily
      living, and among patients younger than 55 years at surgery 20 percent need revision surgery
      within ten years. Revision surgery is more complicated than primary surgery and associated
      with decreased implant longevity due to decreased bone stock. Resurfacing hip arthroplasty
      (RHA), restores the anatomy of the hip as only the articulating joint surfaces are replaced,
      and thus more bone is left to ensure a better opportunity of successful revision surgery
      later on. The clinical midterm evaluation of RHA survival is promising, but two major
      complications leading to early revision, namely osteonecrosis and femoral neck fracture, has
      raised concern regarding the influence of surgical technique on the vascularity of the
      femoral head. RHA is commonly performed through a posterolateral surgical approach. By this
      technique muscle tendons are spilt resulting in decreased patient mobility for several weeks
      after surgery, but more importantly, the blood supply is compromised as a large artery has to
      be ligated. This is speculated to decrease the blood supply to femoral head and neck and
      thereby increase the risk of osteonecrosis, femoral neck fracture, and implant failure. With
      a new surgical technique facilitating an anterolateral approach to the hip joint the blood
      supply is left intact as well as the muscle tendons.

      HYPOTHESIS:

      An anterolateral surgical approach in resurfacing hip arthroplasty will 1) preserve the blood
      supply to the femoral head and neck and improve implant longevity, and 2) spare the muscle
      tendons and ease patient recovery.

      METHOD and FACILITIES:

      50 patients, aged 30 to 60 years, with osteoarthrosis of the hip will be randomised to a RHA
      inserted by either an anterolateral or a posterolateral surgical approach. Primary points of
      evaluation are 1) blood supply to the femoral head and neck measured intraoperatively by
      Laser Doppler flowmetry and postoperatively by microdialysis established during surgery.
      Secondary points of evaluation are 1) implant fixation measured by radiostereometric analysis
      (RSA), and 2) periprosthetic bone mineral density (BMD) measured by dual energy x-ray
      absorptiometry (DEXA), 3) gait analysis and 4) clinical scores of function, pain and
      activities of daily living (Harris Hip Score , Visual Analogue Scale).
    

Intervention name(s): Surgical approach (ReCap Hip Resurfacing System)
Intervention type(s): Procedure
Intervention description(s): two different surgical approaches in hip resurfacing arthroplasty
Other intervention name(s): ReCap Hip Resurfacing System
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: osteonecrosis; femoral neck fracture; implant fixation; implant failure; periprosthetic bone mineral density; gait function; gait analysis; patient recovery