Summary & Overview
CPT 29435: Walking Cast for Tibia and Fibula Shaft Fractures
CPT code 29435 represents the application of a walking cast that immobilizes the lower leg and foot while permitting knee flexion, commonly used for tibia and fibula shaft fractures. Nationally, this code captures a commonly performed orthopaedic procedure that enables stabilized weight-bearing to promote fracture healing while maintaining knee mobility. Accurate coding affects clinical documentation, billing consistency, and payer coverage determinations for fracture management.
Key payers addressed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context for use of a walking cast, comparisons to related cast application codes, common billing modifiers encountered, and typical sites of service for this procedure. The publication also summarizes relevant ICD-10 diagnoses that commonly pair with this code and highlights operational considerations for orthopaedic surgery practices.
This summary is written for a national audience and focuses on the code definition, typical clinical indications, and the aspects of billing and documentation that influence claim adjudication and reporting across major public and private payers.
Billing Code Overview
CPT code 29435 describes the application of a walking cast that immobilizes the lower leg and foot while allowing knee motion. The cast is used in the treatment of tibia and fibula shaft fractures and includes an anterior segment that extends over the knee while covering the lower leg. The device design applies controlled pressure at the fracture site to stimulate callus formation during ambulation.
Service type: Cast application for lower leg fracture (walking cast / weight-bearing immobilization)
Typical site of service: Hospital outpatient department, ambulatory surgery center, or orthopedic clinic / procedure room
Clinical & Coding Specifications
Clinical Context
A 34-year-old male presents to the emergency department after a motorcycle collision with persistent pain, swelling, and deformity of the lower leg. Imaging confirms a closed mid-shaft fracture of the right tibia (S82.301A). The orthopaedic surgeon performs a closed reduction in the ED and applies a walking cast that immobilizes the lower leg and foot while allowing knee flexion to promote weight-bearing-induced mechanical stimulation of callus formation. The procedure occurs in an ambulatory surgical center or hospital outpatient department depending on associated services and patient comorbidities. Post-application workflow includes verification of cast fit and neurovascular status, patient education on weight-bearing precautions and cast care, scheduling of orthopedic follow-up for radiographic monitoring, and documentation of the procedure, laterality (use RT or LT as applicable), and diagnosis. Typical providers include orthopaedic surgeons and emergency medicine physicians with orthopedic subspecialty care coordinating follow-up.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
RT | Right side | Applied when the procedure is performed on the right lower extremity |