Accuracy of OPS™ Femoral Neck Resection Study
Condition: Primary Total Hip Arthroplasty
Study type: Observational

Summary: 
      The primary objective of this study is to determine the accuracy of the Optimized Positioning
      System (OPS™) planning and delivery tools using different types of surgical approaches.
    

Detailed description: 
      Total Hip Replacement (THR) is the gold standard for treatment of severe arthritis of the hip
      as it relieves pain, restores function of the joint and improves quality of life for
      patients. The restoration of hip mechanics can be influenced by the selected femoral stem
      design and also by choices made by the surgeon during the surgical implantation. The
      combination of femoral neck resection level and angle are key factors, particularly in
      cementless hip arthroplasty, in determining post-operative leg length and femoral
      anteversion. Historically, an estimation of prosthesis sizing and positioning has been made
      via a process of manual or digital templating either pre or intraoperatively using images of
      the implants positioned over the standard AP and lateral view hip x-rays taken in advance of
      surgery with generic instruments used during the surgery to execute the femoral head
      resection at the planned level. This process has a number of limitations. The OPS™ system
      utilizes detailed pre-operative imaging including a CT scan to generate a plan for the
      femoral neck resection level and angulation based on the anatomy of the individual patient.
      Following validation of this plan by the operating clinician, a patient specific femoral
      guide instrument is generated to help facilitate the reliable delivery of the planned
      resection intraoperatively. The purpose of this study will be to evaluate the use of the
      patient-specific femoral instrument in the hands of two surgeons using different prosthesis
      combinations and surgical approaches. A total number of 40 participants will be enrolled.
      Participants in this study will return for a single post-operative visit at 6 weeks to have
      X-rays taken and to enable any post-operative study hip related complications to be recorded.
      Once this has been completed, participants will be routinely followed-up by their orthopaedic
      surgeon as required in accordance with standard clinical practice.
    

Intervention name(s): Primary Total Hip Replacement with Trinity cup and TriFit TS stem via posterolateral surgical approach.; Primary Total Hip Replacement with Trinity cup and MetaFix stem via direct anterior surgical approach
Intervention type(s): Device; Device
Intervention description(s): The participant will undergo surgery using the hip prostheses and surgical approach used by their surgeon Investigator. A patient specific femoral guide, generated by the OPS™ plan preoperatively, will be used during the surgical step of femoral neck resection. These are not study specific procedures as the OPS™ system is already in use by the surgeon Investigator in their standard of practice.; The participant will undergo surgery using the hip prostheses and surgical approach used by their surgeon Investigator. A patient specific femoral guide, generated by the OPS™ plan preoperatively, will be used during the surgical step of femoral neck resection. These are not study specific procedures as the OPS™ system is already in use by the surgeon Investigator in their standard of practice.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Study participants will be recruited from the clinic registry at each of the
        investigational sites of those patients requiring a primary hip replacement. Those who meet
        the inclusion/exclusion criteria will be invited to enrol into the study.
      
Keywords: Femoral neck resection, offset, leg lenght, femoral anteversion