(P 90) MEGAPROSTHESIS CONVERSION FROM FAILED OSTEOARTICULAR ALLOGRAFT VERSUS PRIMARY RECONSTRUCTION FOR DISTAL FEMUR AND PROXIMAL TIBIA TUMORS: A PROPENSITY MATCHED-PAIR ANALYSIS

Author(s)

TA

Taha Aksoy, MD

Department of Orthopaedics, University of Miami
Miami, Florida, United States

Co-Author(s)

HM

Hannah Mosher, BS

University of Miami Miller School of Medicine
Miami, Florida, United States
Sergio J. Torralbas Fitz, MSc

Biostatistician
University of Miami
Miami, Florida, United States
Jean G. Louka, MD

Orthopaedic Oncology Fellow
Department of Orthopaedics, University of Miami
Baltimore, Maryland, United States
Erik J. Geiger, MD

Orthopaedic Oncologist
Department of Orthopaedics, University of Miami
Miami, Florida, United States
FH

Francis J. Hornicek, Jr., MD, PhD

Sylvester Comprehensive Cancer Center, University of Miami, Miami, FL, USA; Miller School of Medicine, University of Miami, Miami, FL, USA
Miami, Florida, United States
BC

Brooke Crawford, MD

Department of Orthopaedics, University of Miami
Miami, Florida, United States
HT

H.T. Temple, MD

Professor of Orthopedic Surgery, oncologist
1.University of Miami , Miller School of Medicine, Department of Orthopedic Surgery
Miami, Florida, United States

Objective: Osteochondral allografts have been used to reconstruct osseous defects following periarticular tumor resection around the knee joint. Despite radiologically progressing into a Charcot-type joint, they provided biological solutions and good functional outcomes. However, high long-term failure rates have led to their decline as primary treatment options. When osteoarticular allografts fail, treatment options become limited and depend on the condition of the limb. The aim of this study is to compare failed allograft conversion into megaprosthesis with primary megaprosthesis for reconstruction following tumor resection.

Methods: This retrospective study included patients who underwent osteoarticular allograft reconstruction then conversion to megaprosthesis for tumors of the distal femur or proximal tibia. These patients were matched 1:2 with patients who received megaprosthesis as the primary reconstruction method after segmental resection using propensity scores based on age, gender, BMI, diagnosis, resected segment ratio and implant size. Outcomes assessed included MSTS scores, range of motion (ROM), extensor lag, complications, revisions, amputations, subsequent surgeries and implant survival.

Results: Twenty-three conversion patients were matched with 46 primary megaprosthesis patients. Revision rates were higher in the conversion group (31.8% vs. 19.5%, p=0.43), while amputation rates were similar (4.6% vs 5.0%, p=1.0). No significant differences were found in failure modes or implant survival (p>0.7). MSTS scores were higher in the primary group (25.3 vs 23.2, p=0.079). Time to revision was longer in the conversion group (10.36 vs 8.21 years, p=0.537), though they trended toward less ROM and extensor lag and a higher number of future surgeries.

Conclusion: While functional results were superior with primary reconstruction, megaprosthesis conversion from osteoarticular allograft provided comparable outcomes with reasonable complication rates and implant survival, proving its feasibility.