Patient-Specific Implants
Background
Since 1977, we have designed over 2400 custom implants for patients at HSS. General indications for these patient-specific implants include small stature, severe deformity, complex revision, and clinical problems where no known solution exists.
Examples
Example 1: Extra Small Total Knee Replacement
Pre-op radiographs of 12-year-old with juvenile rheumatoid arthritis in need of bilateral knee replacements
Pre-op 3D CT reconstruction
Pre-op 3D CT reconstruction with implants
Manufactured components
Post-op radiographs
Example 2: Swan Neck Hip Stem
A patient with developmental dysplasia of the hip (DDH) needs a total hip replacement. Engineers are tasked by the patient's surgeon to virtually insert an off-the-shelf, or standard, femoral component into a 3D reconstruction of the patient's CT scan. Due to this patient's femoral deformity, an ideal fit of the standard implant would cause a leg length discrepancy. If this off-the-shelf implant was inserted deeper to maintain limb length, proximal bone would have to be removed. Therefore, a custom implant must be designed. A swan neck hip stem is designed with a varus neck and maintains limb length without sacrificing bone stock. Figure 1 shows a swan neck hip stem next to an off-the-shelf prosthesis and Figure 2 shows a post-op x-ray of a swan neck hip stem.
Swan-neck hip stem video [0.7MB wmv]
Figure 1. Off-the-shelf (left) and custom swan neck hip prostheses (right)
Figure 2. Post-op radiograph of custom swan neck hip prosthesis
Example 3: Coronoid Replacement
Failed internal fixation (plate and screws) of comminuted fracture of the coronoid process.
Pre-op 3D CT reconstruction
Designed a coronoid replacement (hemiarthroplasty) that resurfaces the olecranon & coronoid, articulates with the humerus, and spares the intact medial coronoid tubercle.
1 yr follow-up