Pengembangan Prototipe Megaprostesis Femur Distal dengan Ruang Tandur Tulang untuk Mengatasi Defek Osteoartikular Pasca Operasi Reseksi Tulang Femur Distal: Desain Prototipe, Kajian Biomekanik, Analisis Antropometri Ekstremitas Bawah dan Implementasi pa = Development of a Prototype of Distal Femur Megaprosthesis with Bone Plantation Chamber to Overcome Osteorticular Defects After Distal Femur Bone Resection : Prototype Design, Biomechanical Study, Lower Extremity Anthropometric Analysis and Implementation