Multi-process manufacturing framework: A cost-effective approach for pediatric prosthetic knee joints in above-knee amputations

Existing manufacturing methods for pediatric knee joints can be expensive and resource-intensive, which makes them inaccessible to low and middle-income countries. This challenge is further complicated for toddlers aged 3–5, which is a crucial time for their rapid growth and may necessitate frequent knee joint replacements. This issue demands a framework that can suggest a suitable combination of manufacturing methods for reliable pediatric prosthetic knee joints at an affordable price. This study investigated a multi-process manufacturing approach for a typical polycentric 4-bar knee joint based on Geometric Complexity Score (GCS), Mechanical Strength Requirements (MSR), and Affordability. The GCS matrix identified Additive Manufacturing (AM) as preferable for highly complex parts and Subtractive Manufacturing (SM) for moderately and least complex parts. The MSR analysis categorized components based on stress levels, with the highest stress observed in the pin (147.27 MPa under loading condition 1 and 108.07 MPa under loading condition 2) and the lowest in the washer (4.1384 MPa and 2.71 MPa, respectively). The affordability study evaluated that the production cost index for AM, SM, and the hybrid approach was 0.186, 1, and 0.277, respectively. The results demonstrated that a multi-process manufacturing approach, utilizing AM for complex geometries and SM for simpler components, offers an optimal balance of affordability, strength, and manufacturability. This study paves the way for creating cost-effective, pediatric prosthetic knee joints, enhancing accessibility and quality of life for amputees. Further research is required to refine the design and assess long-term performance through clinical trials.