Clinical History, Examination and Blood Test Results

  • Discussion case 7 is a 72-year old female who presented due to reduced function and minimal pain in her left hip on a background of a previous left total hip replacement, dislocation of the left hip and abductor repair on the left side. She was able to mobilise at presentation with the use of a walking stick.

  • On clinical examination;

    • Broad based Trendelenburg gait

    • Positive Trendelenburg sign on the left side

    • Good range of movement in both hips

    • Able to straight leg raise with both legs

    • Reduced right knee flexion to 90 degrees due to right total knee replacement

    • Intact foot sensation bilaterally

  • Imaging was ordered to assess the cause for her reduced hip function.


Imaging Results

PRE-OP RADIOGRAPHS

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PRE-OP MRI (Coming Soon)

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The plain film pre-operative radiographs demonstrate the increased horizontal femoral offset on the left compared to the contralateral side.

 

PRE-OP CT

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The pre-operative CT scan once again demonstrates the increased horizontal femoral offset. There is no evidence of component loosening.

 

Diagnosis

  • Dehiscence of the left hip abductor muscles plus an increased offset left total hip replacement requiring abductor muscle repair.


planning

  • This patient was recommended to undergo a LARS ligament repair of her left hip abductor muscles. This procedure requires intensive physiotherapy post-operatively and an abductor brace to try and maximise the chance for success. The success rate is approximately 60%.

  • Planning of this procedure was required. In this case the abductor reconstruction is complicated by her increased femoral offset on the left hand side. This was done during the primary procedure to increase stability of the joint. The disadvantage of an increased femoral offset in abductor repair is that it places additional stress on the abductor tendon repair. In order to prevent this and increase the chances of success, it was planned that the acetabular component would be revised to medialise the cup in order to reduce the horizontal femoral offset. A dual mobility bearing was planned to not compromise stability of the joint. Further, if medialisation of the acetabular component could not correct for the increased offset enough, the plan was made to revise the femoral component to further reduce the horizontal offset in the joint to reduce the force through the tendon repair.

  • After correction of the femoral offset, LARS tendon repair would be completed. This involves dissection of the gluteus medius muscle to free it from surrounding scar tissue. Suturing of an artificial ligament graft and fixing this graft onto the great trochanter with bio-absorbable screws.


Treatment

  • The patient underwent revision surgery. The acetabular component was revised in order to reduce the horizontal femoral offset thus reducing the force on the abductor muscles.

  • A new dual mobility bearing was used to reduce dislocation risk.

  • The femoral component did not need to be revised in this instance as horizontal femoral offset reduction was achieved with revision of the acetabular component.

  • LARS ligament repair was then completed as planned using bio-absorbable screws.

INTRAOPERATIVE IMAGES

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Image one is the previous abductor repair. Image two demonstrates the step of fixing the tendon to the trochanter. The tendon is then reflected over the trochanter, as shown in picture three. The final image demonstrates the graft sewn onto the abductor tendon.

 

Imaging Outcomes

POST-OP RADIOGRAPHS

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TWO YEAR POST-OP RADIOGRAPHS

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The immediate post-operative radiographs demonstrate a new acetabular shell with two screws for fixation. There is a large dual mobility bearing in situ. Note the two bio-absorbable screws within the greater trochanter as part of the LARS ligament repair.

There is no obvious displacement of the acetabular or femoral components with the bio-absorbable screws still being in situ.

POST-OPERATIVE VIDEO

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This video was taken at one-year post LARS ligament abductor repair. It is demonstrating the Trendelenburg test which in this patients case is negative. It has been slowed down and looped.


Clinical Outcomes

  • 4-days post-operatively the patient was doing well. It was explained to her the importance of walking with a wide based gait and offloading the repair of the hip abductor muscles by using crutches for six-weeks. Additionally, she was supplied with a Newport abduction brace.

  • At 3-weeks post-operatively the wound had healed well and she was able to walk with a slightly abducted left hip with the aid of crutches as advised. She was able to achieve this without the use of the brace, maintaining hip abduction at all times.

  • At 7-weeks post-op the patient started an intensive regimen of physiotherapy, starting with 2-sessions per day for a period of 6-weeks with the aim to build the strength in her deep hip muscles, gluteus minimus and quadratus femoris.

  • At 8-weeks post-op, she was reviewed once again having completed some intensive physiotherapy. At this stage she was able to walk with the aid of two crutches without the brace. She was advised to progress to walking with a single crutch for a further three months. Hydrotherapy was introduced to the physiotherapy regimen. Low resistance exercises such as use of an exercise bike was advised.

  • At 4-months post-op she was able to straight leg raises and walk with a single stick. She had a slight Trendelenburg gait at this stage.

  • At 2-years post op the Trendelenburg test was negative. The patient was very happy with her reconstructed and revised left hip.


Learning Points

  • Dehiscence of hip abductors from the greater trochanter can be surgically repaired using a LARS ligament repair with a graft – Successful in 60% of patients.

  • Intensive planning is required to ensure the patient is suitable for tendon repair. Horizontal femoral offset is an important parameter which requires optimisation to prevent excessive stress on the abductors of the hip to increase the chance of success. Total hip revision may be required for this.

  • Physiotherapy is a key component post-operatively to ensure success of an abductor tendon repair. The patient has to understand that this is as important as the procedure for a successful recovery.