CPT® Code 29435

The CPT® Code 29435 refers to the application of a patellar tendon bearing (PTB) cast, which is a specialized type of orthopedic cast used primarily for the treatment of stable fractures of the distal tibia. This cast is particularly beneficial as it allows for knee flexion while providing necessary stabilization to the bone during weight-bearing activities. The PTB cast is often utilized as an initial treatment option for such fractures, but it is more commonly employed as a replacement for a long leg cast approximately 4 to 6 weeks after the initial injury. The design of the PTB cast promotes bone healing by facilitating muscular action and intermittent axial compression at the fracture site, which are essential for stimulating bone growth. The application process involves placing the cast in sections over a protective stockinette and minimal padding to ensure comfort and support. The knee is flexed to a right angle during the application, allowing the plaster to be molded flat over the upper calf, creating a triangular cross-section that wraps around the patella while leaving an indentation over the patellar tendon. This specific molding technique is crucial for the cast's effectiveness, as it helps to prevent rotation of the proximal tibia when the patient is weight-bearing. The edges of the cast are carefully trimmed into a wing shape around the femoral condyles, further enhancing stability. Regular follow-up is necessary, with cast changes occurring at 4 to 6-week intervals, and fracture healing can be monitored through X-ray imaging, either with the cast in place or after its removal.