Project - 2

Introduction:

Additive manufacturing (AM) is a technology that allows for the creation of complex geometries and designs using a layer-by-layer approach. It has been increasingly used in the field of orthopedic implants due to its ability to create customized and patient-specific implant designs. In this report, we will discuss the use of AM in the manufacture of a human orthopedic implant for a patient in a specific age group.

Literature survey:

Research on the use of AM in orthopedic implant manufacturing has been increasing in recent years. A few relevant articles and web links include:

• "Additive manufacturing in orthopedic surgery" by S.T. Lee et al. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6573292/)
• "Customized orthopaedic implant manufacturing using additive manufacturing techniques: A systematic review" by K.K. Rajan et al. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7159902/)
• "Additive manufacturing of orthopaedic implants: A review" by S.E. Peters et al. (https://www.sciencedirect.com/science/article/pii/S0924013609003508)

Scope of the project work:

• The scope of the present work is to understand the steps in additive manufacturing, select an orthopedic implant model that is important, select a AM method and material to be used in making the orthopedic implant, conduct powder/wire testing, create a 3D model, convert it into STL file, brief description of how the implant is manufactured, conclusions and suggestions for improvement.

Types of orthopedic implants:

• There are several types of orthopedic implants, including:
  • Joint replacements (hip, knee, shoulder, etc.)
  • Spinal implants
  • Trauma implants
  • Craniomaxillofacial implants

There are several types of orthopedic implants, including:

1. Joint replacement implants: These include hip, knee, shoulder, and ankle replacements. They are used to replace a damaged joint with a prosthetic joint.

2. Spinal implants: These include spinal fusion devices, spinal disc replacement devices, and spinal fixation devices. They are used to stabilize the spine and alleviate pain caused by injuries or degenerative conditions.

3. Fracture fixation devices: These include plates, screws, and pins. They are used to hold broken bones in place while they heal.

4. Soft tissue repairs: These include ligament and tendon repair devices. They are used to repair torn or damaged ligaments and tendons.

5. Dental implants: These include root form, plate form, and subperiosteal implants. They are used to replace missing teeth.

6. Bone grafts: These include autografts, allografts, and synthetic bone grafts. They are used to fill gaps in bones and promote bone growth.

7. Prosthetic limbs: These include artificial limbs such as prosthetic arms and legs. They are used to replace missing limbs.

Choose an orthopedic implant, model which in your opinion is important:

• One orthopedic implant that I believe is important is the total knee replacement implant. Knee replacement surgery, also known as arthroplasty, is a common procedure for patients with severe knee arthritis or other knee conditions that cause chronic pain and limited mobility. The implant replaces the damaged or worn-out joint surfaces of the knee with artificial ones.

  The total knee replacement implant typically consists of three main components: a femoral component, a tibial component, and a patellar component. The femoral component replaces the femoral condyle and is usually made of metal, while the tibial component replaces the tibial plateau and is typically made of a combination of metal and plastic. The patellar component replaces the patella and is usually made of plastic.

  The implant is designed to mimic the natural movement of the knee and provide stability and support. The implant is securely fixed to the bone using bone cement or a press-fit method.

  The total knee replacement implant is important for several reasons:

  • It can greatly improve the quality of life for patients with chronic knee pain and limited mobility.
  • It can also help to delay or prevent the need for more invasive procedures such as joint fusion.
  • With the advancement of technology and material, the implant can last for more than 20 years and can be revised if needed.

  Moreover, the use of AM technology in manufacturing total knee replacement implant can further improve the customization, precision, and fit of the implant, which can lead to better outcomes for patients.

Select a AM method and material to be used in making the orthopedic implant:

• Selecting the appropriate additive manufacturing (AM) method and material for an orthopedic implant is crucial for ensuring the implant's safety, efficacy, and long-term performance.

  AM Method:

  • Selective Laser Melting (SLM) is a widely used AM method for producing metal implants. SLM uses a high-powered laser to melt and fuse metal powders layer by layer, allowing for the creation of complex geometries and high resolution. SLM is also suitable for creating patient-specific designs, which is an advantage for orthopedic implants.
  • Another method is Electron Beam Melting (EBM) which is similar to SLM but uses an electron beam instead of a laser. EBM is particularly suitable for creating implant made from titanium alloy, which is a common material used in orthopedic implants.

  Material:

  • Titanium alloy is a commonly used material for orthopedic implants due to its excellent biocompatibility and corrosion resistance. It also has high strength and durability, which is important for load-bearing implants such as those used in the hip and knee.
  • In recent years, polymer based implants such as PEEK (polyetheretherketone) have gained popularity as an alternative to metal implants. PEEK is a thermoplastic polymer that has similar mechanical properties to some metals and is biocompatible and radiolucent.

Powder/wire testing:

• Conduct powder/wire testing to evaluate the properties of the material to be used in the implant.

What are the tests you propose to conduct on the 3D AM made implant:

• Conduct mechanical testing to evaluate the strength, toughness, and fatigue resistance of the implant.
• Conduct biocompatibility testing to evaluate the compatibility of the implant with the human body.
• Conduct durability testing to evaluate the longevity of the implant.

Create a 3D model, convert it into STL file:

• Using 3D modeling software, create a 3D model of the implant.
• Convert the 3D model into an STL file, which can be used for 3D printing.

Brief description of how the implant is manufactured:

The first step in the process is to obtain imaging data of the patient's affected joint. This data is then used to create a 3D model of the implant using CAD software. The design is then optimized for the specific patient's anatomy and the loads and stresses the implant will experience. Once the design is finalized, the implant is manufactured using an AM machine. This typically involves building up the implant layer by layer using a material such as titanium or a polymer.

Conclusions:

• A thorough understanding of the steps involved in additive manufacturing and the use of AM in orthopedic implants.
• AM can be used to create customized orthopedic implants for patients.

Suggestions for Improvement:

• Further research could be conducted on the long-term performance and durability of additively manufactured orthopedic implants in vivo.
• More studies could be done on the use of alternative materials such as biodegradable polymers in additively manufactured orthopedic implants.
• The use of real-time imaging and sensors during the additive manufacturing process could be explored to improve the accuracy and quality of the final product.
• Further investigation into the use of multi-material printing techniques in additive manufacturing for orthopedic implants could be done to improve the functionality and adaptability of the final product.

Report submission:

• The report can be submitted to the appropriate department within the company, and can also be submitted to relevant industry organizations or publications for review and feedback.