Total knee arthroplasty in a patient with a fused ipsilateral hip

Kevin Koo, Khang Chiang Pang, Wilson Wang

Many patients undergoing total knee replacement for joint degeneration may have cartilage wear in other joints and thus may already have had various other surgical procedures performed for these. To date, there is no data or description in the medical literature detailing how to perform a total knee replacement in a patient who previously underwent an ipsilateral hip fusion. We describe how this is done in a patient who had her ipsilateral hip fused in 30° of flexion. This presents a surgical challenge because the knee can only be flexed to 70° if done in the conventional supine position. This not only makes exposure more difficult but can also lead to complications including component malpositioning and extensor mechanism problems, such as patellar tendon rupture. We present this case study and describe, with the aid of a series of intra-operative photographs, how this can be performed, with special focus on patient positioning to optimize knee exposure in a patient with a previous hip fusion. The modifications made during surgery allowed the knee replacement to be carried out uneventfully. The patient recovered well and was able to return to her usual activities. We had to make various modifications to the intra-operative positioning in order to carry out the surgery. We hope these practical pointers will help clinicians faced with a similar situation in the future.