The use of modular total knee prostheses in femoral defects in traumatic and revision patients: a prospective case series

Abstract

Background: Management of distal femoral bone defects represents a great challenge, whether these defects are caused by failed total knee arthroplasties or trauma. One method of management is the use of modular hinged total knee implants with distal femoral replacement, depending on the present defects. Such prostheses can be used in revision surgery, acute comminuted distal femoral fracture, or distal femoral fracture with nonunion. This study aimed to analyze the functional outcome and possible complications of the use of modular total knee prostheses in revision surgery or traumatic injuries in patients with femoral defects. Methods: This study was a prospective case series of nononcologic femoral endoprosthetic reconstructions for either revision total knee arthroplasty (TKA) or traumatic femoral defects in eight patients (n=8) from 2015 to 2020. Patient cases were categorized as failed TKA (n=4) or traumatic (n=4). Traumatic patient cases were either distal femoral fractures with nonunion (n=2) or periprosthetic fractures (n=2). Mean follow-up was 2.75 yr (range from 6 mo to 4 yr). Clinical outcomes and ambulatory status (able to walk or not) were assessed. Knee Society Scores (KSS) were calculated, and the range of motion (ROM) was assessed. Results: In this group of patients, modular endoprosthetic replacement provided immediate pain relief, early mobilization, and weightbearing. KSS was improved in all patients. ROM was 70 to 90 degrees in four patients, and 90 to 110 degrees in four patients. None of the patients developed soft-tissue infection or implant loosening during the follow-up period. Conclusions: Short-term clinical outcomes for the use of modular endoprosthetic total knee implants in the management of distal femoral defects in either traumatic injury or revision surgery result in good functional outcome and patient satisfaction. Level of Evidence: Level III.