Perbandingan Luaran Fungsional Dan Radiologis Antara Teknik Masquelet Konvensional Dan Masquelet Modifikasi Dengan Kombinasi Umbilical Cord-Derived Mesenchymal Stem Cells Pada Kasus Defek Kritis Tulang Panjang Akibat Trauma = Functional and Radiological Outcomes of Conventional Masquelet Compared With Modified Masqueled Technique Using Combination of Umbilical Cord-Derrived Mesenchymal Stem Cells in Critical-Sized Long Bone Defect