This study investigates the use of a 3D-printed titanium metatarsal prosthesis designed using finite element analysis (FEA) to treat a patient with a first metatarsal bone defect. The prosthesis features a lightweight, durable design with a microporous surface for bone integration, along with a polyethylene sesamoid for weight-bearing.
Prosthesis Design and FEA Optimization:
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Model A: The initial prosthesis was a direct replica of the healthy metatarsal.
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Model B: Optimized through FEA to reduce weight by 63% without compromising strength. FEA simulations showed that Model B experienced lower displacement and stress compared to Model A.
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Microporous Structure: The titanium prosthesis was designed with a microporous surface to encourage bone growth and improve long-term stability.
Manufacturing Process:
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The prostheses were produced using Direct Metal Laser Sintering (DMLS) for titanium and CNC machining for the polyethylene sesamoid.
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Both components were sterilized and prepared for surgery.
Surgical Procedure:
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The patient underwent a two-step procedure: removal of the previous bone cement filling and implantation of the 3D-printed prosthesis.
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The prosthesis was securely fixed using screws and locking structures, and the operation was completed smoothly with minimal blood loss.
Postoperative Evaluation:
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X-rays and CT Scans confirmed the proper placement and stability of the prosthesis.
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Clinical Scores: The AOFAS score improved from 48 pre-surgery to 88 at 15 months, and the VAS pain score dropped from 7 to 1.
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Plantar Pressure Tests: Showed effective pressure distribution, with pressure on the affected side being better managed by the polyethylene sesamoid.
Conclusion:
The 3D-printed titanium prosthesis, optimized for lightweight design and bone integration, successfully restored the patient's foot function. The microporous structure and polyethylene sesamoid effectively supported weight-bearing and improved comfort. This approach offers a promising alternative to traditional bone grafting methods for large metatarsal defects, showcasing the potential of 3D printing and FEA in personalized orthopedic implants.