Two-stage Operations for Treating Floating Knee Periprosthetic Fractures: A Case Report and Literature Review

Abstract

Periprosthetic fractures (PPFs) in total knee arthroplasty (TKA) are challenging for orthopedic surgeons. A floating knee injury around TKA, especially with component loosening, attributes more complexities in management for the joint reconstruction surgeons. Here, we report a case of floating PPFs around the total knee prosthesis. A 54-year-old female patient suffered from major trauma in a motor vehicle crash. The resuscitation protocol was initiated quickly in the Emergency Department. After primary and secondary surveys, bilateral multiple rib fractures, hemothorax, facial bone fractures, and head concussion syndrome were confirmed. The patient also had a floating periprosthetic open fracture around her left total knee prosthesis (Gustilo Type II). This high-energy trauma resulted in comminuted fractures in the base of her femoral and tibial components, both of which were loosened and displaced. The extensor mechanism of the left knee was also disrupted due to the fracture of the tibial tuberosity. Urgent wound debridement with bridging external fixation across her left knee was performed soon after her vital signs were stabilized. Instead of replacing the distal femur and proximal tibia with mega-prosthesis, we planned a two-staged operation to preserve bone stock given her relatively young age. She received a 1st-stage operation with dual buttress plate fixation for both the femur and tibia around her prosthesis. After 4 months, solid bone union occurred. The 2nd-stage operation involved the removal of hardware and revision TKA with a Zimmer condylar constraint knee system 9 months after the trauma episode. In the outpatient department follow-up, the patient was pain free, with an acceptable range of motion. She can now walk smoothly without an assistive device. We offered an alternative to treat floating knee PPF around the total knee prosthesis, with better preservation of the bone stalk, lower constraint level, and good clinical outcome.

Keywords

• floating total knee
• periprosthetic fracture
• total knee arthroplasty