Cemented Hemiarthroplasty of the Hip in a Patient with Ipsilateral Knee Arthrodesis: Surgical Difficulties and Techniques

INTRODUCTION: Standard references such as knee and lower leg position cannot be used in patients with knee arthrodesis with destroyed distal femur anatomy. The resulting component malposition can culminate in dislocation, decreased range of motion, impingement, and wear. To our knowledge, no cases on surgical techniques have been reported in such patients. We describe a simple technique that guides a surgeon in assessing the femoral stem version in such cases. CASE REPORT: A 80-year-old female sustained right sided neck of femur fracture. She had a history of bone tumor, which was treated with resection and arthrodesis. Subsequently, the patient developed osteomyelitis which healed gradually. The difficulties, in this case, were inability to flex the knee, to determine the trans-epicondylar axis and to use the ankle as a reference. Using lesser trochanter as reference neutral rotation of the limb was determined and K wire was inserted in distal femur of the patient. A post-operative computed tomography (CT) was done to assess the stem version. CONCLUSION: Our main aim in presenting this case was to emphasize on the surgical technique. A pre-operative CT scan should be done to evaluate the distal femur anatomy and calculate the lesser trochanter versions of the normal limb. We recommend the use of K wire inserted into the distal femur after determining the neutral version of the limb and comparing the lesser trochanter profile with the normal side.