Clinical History, Examination and Blood Test Results

  • Discussion case 3 presents a 71-year old gentleman who presented with worsening pain in his left hip, left knee and back.

  • This pain is on a background of;

    • Slipped upper femoral epiphysis in 1960.

    • A previous left hip arthrodesis in 1969.

  • Prior to the presentation, he was able to swim three times per week, taking ibuprofen for any exacerbation of his pain.

  • On examination;

    • Arthodesed left hip.

    • Bilateral grade III knee effusions with medial joint line tenderness worse on the right.

  • MRI scans were arranged of the lumbar spine, hips and right knee;

    • MRI of lumbar spine and hips – To determine if the patient would be a suitable candidate for a reversal of the left hip arthrodesis.

    • MRI of right knee – To determine the need for a right knee replacement.


Imaging Results

PRE-OP AP PELVIS

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PRE-OP RIGHT KNEE

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Pre-op radiograph shows a fracture in the arthrodesis prosthesis with metallic fragments projecting over the left proximal femur. There is a complete loss of joint space with remodelling in the left hip joint and some mild degenerative change in the right hip.

Right knee films were taken to assess for a cause of right knee pain. This demonstrated some considerable lateral compartment degenerative changes.

 

PRE-OP MRI

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Left hip MRI scan reveals gross fatty atrophy of all the muscles surrounding the left hip, more marked in the left adductor muscles. The gluteal insertions appear intact.

 

Clinical history continued

  • The left hip and lumbar spine MRI were promising, revealing a reduced muscle bulk with good insertions.

  • This patient was reviewed by our physiotherapy team using an ultrasound scan to assess contraction of his left hip abductors;

    • Atrophy of the left quadriceps, hamstrings, calf and the gluteus maximus muscle.

    • Palpation revealed good contraction of the gluteus medius muscle in isometric hip abduction.

  • A CT scan was ordered to plan for his hip replacement. Planning is required to size the femoral stem and a dual mobility socket.

  • An EOS scan and a 3D MRI CT fusion was also utilised to help in the planning of the left hip replacement.


Imaging Results Continued

PRE-OP CT

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PRE-OP EOS

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This pre-operative CT was used in the planning of this patients’ hip replacement. It demonstrated a bone on bone appearance to the left hip, with osseous bars projecting from the anterior and posterior wall of the acetabulum into the corresponding femoral head and lesser trochanter. There is a changed morphology to the femoral head. Left iliopsoas has lost roughly 50% of its volume and there is grade 3 fatty atrophy in gluteus medius and maximus. Some degenerative changes are seen in the right hip.

EOS scan used to assess for any pre-operative leg length discrepancy in a functional position to aid in the planning of the procedure.

 

PRE-OP 3D MRI/CT FUSION

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This MRI CT fusion was used to produce a 3D model of the patients left proximal femur to help plan the procedure.

 
 

PRE-OP VIDEO

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This video was taken on the morning of the operation to demonstrate how the patient was mobilising prior to the procedure.


Diagnosis

  • Left hip arthrodesis causing significant pain requiring a conversion to a left arthroplasty.


Treatment

  • This patient underwent reversal of his left hip arthrodesis after one year of meticulous planning and physiotherapy.

    • Posterior approach

    • Dissection of the joint with 4-stay sutures

    • Removal of the old metal pin

    • Osteotomy

      • Femoral fracture

      • 2 cables used

    • True floor of acetabular socket identified

      • 56mm Trident titanium hemispherical shell inserted - 1 screw for good fixation

      • Restoration dual mobility bearing 28mm/48mm

    • Femoral implant

      • Restoration 155mm length/15mm diameter femoral stem used with a 25mm body + 0

      • Biolox delta ceramic femoral head 28mm

      • Joint stable

    • Wash ++

    • Vicryl, monocryl and glue to close

    • Post-operatively

      • Partial weight bearing for 6-weeks as pain allows

      • Clexane

      • Radiograph and EOS to assess implant position


Imaging Outcomes

7-WEEK POST-OP RADIOGRAPH

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4-MONTH POST-OP RADIOGRAPH

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There is reduced bone density of the left greater trochanter, presumably relating to the previous conversion of the arthrodesis to THR. Cerclage wires are containing an oblique periprosthetic fracture of the posterior left femoral shaft. These post-operative radiographs demonstrated an adequate position of the implants.

No movement of the implant is seen. There is some callus formation surrounding the periprosthetic fracture.

 

POST-OP EOS

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Post-operative EOS measurements revealed a functional leg length discrepancy of 3mm when standing, mainly due to an oblique pelvis.

 

Clinical Outcomes

  • This patient was reviewed in clinic at 7-weeks post-op;

    • Wound had healed with primary intension

    • Orthotics measured a 1.5cm leg length discrepancy and organised a shoe raise

    • He was walking comfortably with a single crutch

    • On examination his left hip flexion was limited to 40 degrees, following which the pelvis takes over. The abductors were contracting in resisted abduction.

  • The patient then returned at 4-months post-op;

    • He was pleased he had undergone the reversal of his arthrodesis

    • Functional EOS imaging reveals a leg length discrepancy of only 3mm when standing


Learning Points

  • Arthrodesis reversal requires meticulous planning and pre-operative assessment especially of hip muscle strength.

  • Physiotherapy input pre-operatively is required to build muscle bulk surrounding the arthrodesed hip and to help in the assessment of post-operative function.

  • 3D MRT CT fusion can be used to plan the position of an implant within the patients 3D bony anatomy.