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Femoral Component Offset:


- Discussion:
    - see acetabular component, reestablishment of acetabular floor, and component position;
    - see: preoperative and post operative radiographic eval
    - femoral offset is measured from the distance between the center of the femoral head and a line drawn down center of femoral shaft;
    - note that increasing offset may have the unwanted effect of increasing rotational torque on the stem (leading to aseptic loosening);
    - offset may be increased by:
           - increasing stem varus from the typical 135 deg;
                    - references:
                           - Are Gender-specific Femoral Stems Needed?
                           - The effectiveness of dual offset stems in restoring offset during total hip replacement
                           - Do post-operative changes of neck-shaft angle and femoral component anteversion have an effect on clinical outcome following uncemented total hip arthroplasty?
           - lateralization:
                    - shifting the neck trunion medially;
                    - lateralization of the femoral shaft restores offset, reduces femoropelvic impingement, and increases abductor tension.
                    - lateralization also increases the lever arm for the abductor muscles;
                    - lateralization may be required with medialization of the cup
                    - increasing modular neck length (which will also increase verticle offset and leg length)
                    - references:
                            - Effect of femoral component offset on polyethylene wear in total hip arthroplasty.
                            - Benefit of cup medialization in total hip arthroplasty is associated with femoral anatomy
                            - The anatomic basis for concept of lateralized femoral stems: a frontal plane radiographic study of proximal femur.
                            - Total hip replacement: increasing femoral offset improves functional outcome



- references:
           - Total hip replacement: increasing femoral offset improves functional outcome.
           - A relationship between stem orientation and function following total hip arthroplasty.
           - Femoral component offset. Its effect on strain in bone-cement.
           - Effect of femoral offset on range of motion and abductor muscle strength after total hip arthroplasty.
           - Reconstructed Hip Joint Position and Abductor Muscle Strength After Total Hip Arthroplasty.
           - The influence of femoral offset on health-related quality of life after total hip replacement
           - Managing Length and Stability: The Role of the Modular Neck
           - Effect of femoral offset on pain and function after total hip arthroplasty.
           - Total hip arthroplasty: leg length inequality impairs functional outcomes and patient satisfaction.
           - Femoral offset: Anatomical concept, definition, assessment, implications for preoperative templating and hip arthroplasty
           - The effect of femoral offset modification on gait after total hip arthroplasty