The femoral component chosen for the primary THA was not suitable for this patient as it created an excessive offset and resulting tension of the soft tissue, leading to the failure of the abductor muscle repair shortly after surgery. Pre-operative templating would have permitted the identification of a more appropriate offset measurement. A variety of alternative prostheses could have been trialled on-screen in order to select one with a shorter offset before going into the OR.
This patient’s unusual physiognomy would not have been apparent through external examination or in the OR. Using an unsuitable implant led to the early failure of the abductor muscle repair and, ultimately, the need for revision surgery just one year after the primary THA. Digital templating would also have revealed that this patient has extremely small bones, not always obvious when radiographs are viewed in the traditional way.
“Pre-op templating would have permitted the identification of a more appropriate offset.”
- Mr. Grant Shaw, Orthopaedic Surgeon
Case Details
A young (mid 50s), fit, female patient presented as ‘bitterly disappointed’ with initial hip replacement surgery. One year after surgery, she was still unable to walk without a stick, and the surgeon who assessed her described her condition as, “…the worst case of Trendelenburg gait I have seen”. The obvious Trendelenburg gait was a clear indication of a weakened or damaged gluteus medius muscle due to these muscles being cut and subsequently reattached during the THA surgery, which used the anterior-lateral approach.
The diagnosis for this patient was that the abductor muscle repair had failed very soon after surgery (she was able to recall the moment when the abductor muscle detached just two days post-surgery). A digital pre-operative plan was created prior to the revision surgery, which enabled the surgeon to identify a more suitable prosthesis and correct the previously excessive offset. The abductor muscle was reattached during the procedure.
Measurements of the primary post operative x-ray show that the right femoral offset was 42 mm compared with 32 mm on the left – suggesting that the original right femoral offset was also likely to be about 32 mm. This increase in offset would have put the abductor muscles under extra tension after surgery. The repair was therefore more vulnerable to failure, especially in the case of a young active patient keen to ‘get on with her life’.
Revision surgery was performed to restore the correct offset and so achieve the correct muscular tension. A cemented Stryker Exeter stem, size #0, 35.5 offset #0, Head 22, was used, and the abductors were repaired with soft tissue anchors.
Our thanks go to Mr. Grant Shaw, Orthopaedic Surgeon at Queen Alexandra Hospital in Portsmouth, United Kingdom, for contributing this case.