Compatibility of Retrograde Intramedullary Nails With Knee Prostheses: A Comprehensive Analysis.

BACKGROUND: Periprosthetic distal femoral fractures pose major challenges in orthopaedic surgery, particularly among aging populations with total knee arthroplasties. Retrograde intramedullary nailing has emerged as a viable fixation option due to its biomechanical stability, less invasive nature, and facilitation of early weight-bearing. However, the compatibility between retrograde nails and various knee prostheses remains a critical determinant of surgical success. This review consolidated existing knowledge and evaluated current nail-prosthesis compatibility and options for lateral femoral periprosthetic plating and provided a compatibility matrix for fixation options for these complex fractures.

METHODS: An evidence-based review was conducted to evaluate the compatibility of retrograde intramedullary nails with total knee arthroplasty prostheses. Additionally, currently available lateral distal femoral plates were evaluated. Data were synthesized from key studies, technical specifications from major manufacturers, and recent advancements in nail and prosthesis design. Technical parameters such as intercondylar dimensions, posterior notch geometry, nail diameter, and proximal sagittal nail bend angles were analyzed. The findings were summarized in comprehensive tables, cross-referencing nail systems with prosthesis models to identify optimal combinations and highlight potential challenges.

RESULTS: The analysis identified critical factors influencing nail-prosthesis compatibility, including nail diameter, intercondylar width, and posterior notch geometry. These findings were synthesized into detailed tables categorizing prosthesis compatibility by manufacturer, model, and technical specifications.

CONCLUSIONS: This paper provides a comprehensive resource for optimizing retrograde nail selection based on prosthesis-specific geometries, addressing a critical aspect of managing periprosthetic distal femoral fractures. Although advancements in nail and prosthesis designs have improved compatibility, variations in posterior notch placement and intercondylar dimensions highlight the importance of preoperative planning.