Ultra-Short Anatomic and Conventional Cementless Stems Cementless Stems in Patients Younger Than Fifty-Five Years Old
Condition: Hip Replacement, Total; Osteonecrosis of Femoral Head; Coxarthrosis
MeSH terms: Osteonecrosis; Osteoarthritis, Hip
Study type: Interventional
Phase: Phase 4

Summary: 
      As clinical and radiographic performance of an ultra-short anatomic cementless stem have been
      investigated only two randomized controlled studies, well-designed trials should aim for a
      thorough comparison of the outcomes of ultra-short and conventional cementless stems. The
      purpose of this study was to compare the outcomes of ultra-short and conventional stems in
      the same young patients who underwent simultaneous bilateral sequential total hip
      arthroplasties.
    

Detailed description: 
      Conventional cementless femoral stems are known to provide a high rate of satisfactory
      clinical outcomes at long-term follow-ups. However, they may have potential clinical
      consequences related to stress shielding, thigh pain, periprosthetic fractures,
      proximal/distal dimensional mismatch, an easier access pathway for wear debries and removal
      during revision. In an effort to reduce the risk of stress shielding, thigh pain,
      periprosthetic fracture, proximal/distal stem mismatch, and to facilitate removal of well
      fixed stem, a new ultra-short anatomic metaphyseal-fitting cementless femoral stem was
      developed. It was designed to provide closely mimicking the original functioning hip. The
      absence of the diaphyseal anchorage attempt proximal load transfer to reduce stress
      shielding, thigh pain and proximal distal/mismatch. Furthermore, it attempts to preservation
      of the femoral canal and femoral elasticity and ease of revision. The question thus arises
      whether it is possible to obtain strong and long-lasting fixation of the femoral component
      without diaphyseal anchoring.

      As clinical and radiographic performances of this ultra-short stem have been investigated
      only in a few studies and at short-term follow-ups, it remains to be elucidated whether an
      ultra-short stem shows a low incidence of implant loosening, stem misalignment,
      intraoperative fractures and revision rate. The purpose of this randomized controlled study
      to compare: (1) the clinical results, including Harris hip score, thigh pain, Western Ontario
      and McMaster Universities Osteoarthritis (WOMAC) Index score, and patients' satisfaction; (2)
      radiographic results, including stress shielding, implant loosening, stem misalignment; and
      (3) intraoperative fractures and revision rates of cementless total hip arthroplasty using an
      ultra-short anatomic metaphyseal-fitting cementless femoral stem versus a conventional
      metaphyseal and diaphyseal fitting anatomi proximal porous-coated cementless stem in the same
      patients who underwent bilateral simultaneous sequential total hip arthroplasty under one
      anesthetic.
    

Intervention name(s): Total hip replacement
Intervention type(s): Procedure
Intervention description(s): Simultaneous bilateral sequential total hip arthroplasties under the same anesthetic.
Randomization to treatment with an ultra-short or a convnetional cementless stem was accomplished with use of study numbers in sealed envelope, which were opened in the operating room before the skin incision was made.
The pore size was 250㎛. A 28-mm-diameter Biolox forte ceramic femoral head (CeramTec AG, Polchingen, Germany) ) was used in all hips. A cementless cup and a 28mm internal-diameter Biolox forte ceramic liner was used in all hips in both groups.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment