(Materialise) – As guest speaker in our latest webinar series on hip and lower extremities applications, Dr. med. Simon Weidert discusses his experience with a patient-specific implant in acetabular defect reconstruction; his first with Materialise’s aMace solution.
Dr. Weidert is a consultant at the trauma orthopedic department and head of the computer-aided surgery and simulation research group, in the Munich University Hospital in Germany. He mainly works on primary and trauma surgeries and has great interest in 3D printed applications. 3D-printed anatomical models for the use of pelvic fractures are already standard in his hospital.
Examining the acetabular defect
The case discussed by Dr. Weidert is that of a 33-year-old male patient. The patient’s injuries were caused by a motor vehicle accident that occurred over two years ago in an Eastern European country. His extensive injuries comprised several fractures, including an acetabular fracture (which caused shortening of the leg), peroneal nerve injury, radial nerve injury, and injury in his left knee ligament. The acetabular fracture could not be treated due to the patient’s condition at the time, and had been left to heal as such.
The patient’s mobility was largely confined to a wheelchair. Using crutches was extremely difficult because of the “dropped foot” resulting from the peroneal nerve injury and because of his recent radial nerve reconstruction, causing the need for support from others. He had a T-shaped fracture with a dislocated postero-caudal segment that had healed in a faulty position. The femoral head had destroyed the acetabular rim in the postero-cranial part and the new hip center was more than three centimeters higher than its original anatomical center. This resulted in a Paprosky type 3A defect.
Defining an ambitious strategy
Classic strategies such as tantalum grafts and bone grafts were first considered for treatment. But as bone loss was so high, reconstruction of the acetabulum would be very difficult. Still, Dr. Weidert and his team wanted to find a solution to help their young patient, and decided a new approach was necessary: they contacted Materialise and sent them the patient’s CT scans.
As part of the preoperative analysis provided by Materialise, the report showed a quantitative representation of the bone loss and the deformation of the acetabulum.
Starting from this analysis, the acetabular reconstruction was planned. In the report Materialise provided a proposal of the implant position and orientation, and the screw configuration. The surgeon had full control over the design and within a few phone calls with Materialise an optimal reconstruction was discussed.
Image Credit: materialise