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CPT 29405: Short Leg Cast for Lower Leg Fracture or Severe Ankle Sprain

Headline: CPT code 29405: Short leg cast application for lower leg fractures and severe ankle sprains

Lead: CPT code 29405 denotes application of a short leg cast that immobilizes the lower leg from just below the knee to the foot while leaving the toes free. The code captures a common orthopaedic immobilization procedure used for tibia and fibula fractures and significant ankle sprains, and it is relevant across acute and outpatient care settings.

CPT code 29405 represents placement of a short leg cast for stabilization and immobilization of lower leg fractures or severe ankle sprains. Nationally, this code matters because cast application is a high-volume, procedure-driven service that impacts emergency, urgent care, and outpatient orthopedic workflows and resource planning.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context, typical sites of service, and the operational considerations tied to this code. The publication also provides benchmarking and reimbursement context, common modifier usage, and guidance on documentation elements necessary to support billing for immobilization procedures where available.

This summary equips clinical, coding, and revenue-cycle stakeholders with a focused reference on CPT code 29405, emphasizing clinical indications, care settings, and the payer landscape relevant to cast application services.

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Billing Code Overview

CPT code 29405 describes application of a short leg cast to the lower leg to treat a fracture of one or both bones of the lower leg (tibia and/or fibula) or a severe ankle sprain. The short leg cast extends from just below the knee down over the foot while leaving the toes free.

Service type: Cast application / immobilization

Typical site of service: Emergency department, urgent care, ambulatory surgery center, or outpatient orthopedic clinic

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CPT 29405: Short Leg Cast for Lower Leg Fracture or Severe Ankle Sprain

Headline: CPT code 29405: Short leg cast application for lower leg fractures and severe ankle sprains

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Get alerted when payer policies referencing 29405 are released or updated.

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Billing Code Overview

Service type: Cast application / immobilization

Typical site of service: Emergency department, urgent care, ambulatory surgery center, or outpatient orthopedic clinic

Clinical & Coding Specifications

Clinical Context

A 42-year-old patient presents to the emergency department after slipping on wet pavement and reporting severe left lower-leg pain and inability to bear weight. Physical exam reveals localized tenderness over the tibia and fibula with swelling and deformity. Radiographs confirm a nondisplaced tibial shaft fracture without neurovascular compromise. The orthopedic clinician elects to apply a short-leg (below-knee) cast to stabilize the fracture for pain control and immobilization while arranging definitive follow-up care.

The clinical workflow includes triage and triage imaging (plain radiographs), orthopedic evaluation, informed consent, cast application using stockinette, padding, plaster or fiberglass material, molding and trimming, post-application neurovascular check, patient education on cast care and weight-bearing status, and documentation of procedure, time, and laterality. Typical follow-up occurs in orthopedic clinic within 1–2 weeks for reassessment and repeat imaging as needed.

Coding Specifications

Modifier	Description	When to Use
`RT` / `LT`	Right side / Left side	Use to indicate laterality when casting a single lower leg; e.g., `LT` for left short-leg cast.
`25`	Significant, separately identifiable E/M service by the same physician on the same day	Use when a significant evaluation is performed and documented on the same day as cast application.
`52`	Reduced services	Use when a full cast application is not completed as described (partial or abbreviated procedure).
`53`	Discontinued procedure	Use when casting is initiated but discontinued due to unforeseen circumstances.
`59`	Distinct procedural service	Use when a separate, distinct procedure is performed on the same date that is not normally reported together.
`76`	Repeat procedure by same physician	Use when the cast application is repeated by the same physician during the same encounter.
`77`	Repeat procedure by another physician (not in provided list)	Not listed in input; excluded per rules.
`78`	Unplanned return to the operating/procedure room by the same physician following initial procedure (not common for simple cast)	Use if an unplanned return to procedure area occurs for cast revision under the same encounter.
`52`	Reduced services	(Note: listed once above) Duplicate entries avoided — use as above.
`22`	Increased procedural services	Use when the application required substantially greater work than typical (extensive manipulation or complicated molding) and documentation supports the increased complexity.
`59`	Distinct procedural service	(Note: listed above) Avoid duplication — see above.

Taxonomy Code	Specialty	Notes
`207K00000X`	Orthopedic Surgery	Orthopedic surgeons commonly apply and oversee casts for lower leg fractures.
`207L00000X`	Podiatry	Podiatrists may apply short-leg casts for ankle and distal tibia/fibula injuries.
`2080P0003X`	Emergency Medicine	Emergency physicians frequently perform initial cast application in the ED setting.
`163W00000X`	Nurse Practitioner	NPs in orthopedics or urgent care often apply casts under protocol.
`363A00000X`	Physician Assistant	PAs in orthopedics or emergency medicine commonly perform cast applications.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`S82.201A`	Unspecified fracture of shaft of right tibia, initial encounter for closed fracture	Tibial shaft fractures are commonly immobilized with a short-leg cast.
`S82.202A`	Unspecified fracture of shaft of left tibia, initial encounter for closed fracture	Left-sided tibial shaft fracture treated with short-leg cast.
`S82.401A`	Unspecified fracture of lateral malleolus of right fibula, initial encounter for closed fracture	Distal fibula (lateral malleolus) fractures often receive short-leg casting for immobilization.
`S82.402A`	Unspecified fracture of lateral malleolus of left fibula, initial encounter for closed fracture	Left lateral malleolus fracture commonly managed with below-knee cast.
`S93.401A`	Sprain of unspecified ligament of ankle, initial encounter	Severe ankle sprains with instability may be immobilized in a short-leg cast.
`S82.841A`	Other fracture of medial malleolus, right lower leg, initial encounter for closed fracture	Medial malleolus fractures frequently require short-leg casting for stabilization.
`S82.842A`	Other fracture of medial malleolus, left lower leg, initial encounter for closed fracture	Left medial malleolus fracture treated with cast immobilization.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`29405`	Application of short leg cast (below-knee)	Primary procedure code for application of a short-leg cast; used to immobilize fractures of the tibia/fibula or severe ankle sprains.
`20690`	Application of unna boot; includes debridement and dressing	May be used in the same clinical course for soft-tissue management or adjunctive immobilization techniques, though not typically billed on the same day as definitive cast application.
`29075`	Application of external fixator, distal tibia/fibula (temporary external fixation)	Performed when temporary stabilization using external fixation is required prior to or instead of casting in more severe fractures.
`99070`	Supplies and materials (except spectacles), non-covered items used in the patient’s treatment	Used to bill non-implant supplies associated with cast materials if payer allows separate supply reimbursement.
`11042`	Debridement, subcutaneous tissue (for wound management)	May be performed prior to casting if open wounds require debridement before immobilization.

CPT 29305: Hip Spica Body Cast for Trunk and One Leg Immobilization

CPT-29325-HIP-SPICA-BODY-CAST-APPLICATION

CPT 29325: Hip Spica / Trunk and Leg Body Cast Application

CPT-29345-LONG-LEG-CAST-APPLICATION-IMMOBILIZATION

CPT 29345: Long Leg Cast Application, Leg and Knee Immobilization

CPT-29355-LONG-LEG-AMBULATORY-CAST-APPLICATION

CPT 29355: Long Leg Ambulatory Cast Application

CPT-29358-LONG-LEG-BRACE-CAST-FEMUR-FRACTURE-IMMOBILIZATION

CPT 29358: Long Leg Brace-Type Cast for Femur Fracture

CPT-29365-CYLINDER-CAST-LEG-KNEE-IMMOBILIZATION-FRACTURE

CPT 29365: Cylinder Cast for Leg and Knee Immobilization

CPT-29425-LOWER-LEG-CAST-APPLICATION-TIBIA-FIBULA-ANKLE

CPT 29425: Lower Leg Cast Application for Tibia/Fibula Fracture or Severe Ankle Sprain

CPT-29435-WALKING-CAST-LOWER-LEG-TIBIA-FIBULA-FRACTURE

CPT 29435: Walking Cast for Tibia and Fibula Shaft Fractures

CPT-29440-REMOVABLE-WALKER-OR-HEEL-PAD-FOR-LEG-CAST

CPT 29440: Addition of Removable Walker or Heel Pad to Leg Cast

CPT-29445-TOTAL-CONTACT-WALKING-CAST-FOR-DIABETIC-ULCER-OFFLOADING

CPT 29445: Total Contact Walking Cast for Diabetic Foot Ulcer

Showing 1–10 of 11

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

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Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

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Clinical & Coding Specifications

Clinical Context

Coding Specifications

Modifier	Description	When to Use
`RT` / `LT`	Right side / Left side	Use to indicate laterality when casting a single lower leg; e.g., `LT` for left short-leg cast.
`25`	Significant, separately identifiable E/M service by the same physician on the same day	Use when a significant evaluation is performed and documented on the same day as cast application.
`52`	Reduced services	Use when a full cast application is not completed as described (partial or abbreviated procedure).
`53`	Discontinued procedure	Use when casting is initiated but discontinued due to unforeseen circumstances.
`59`	Distinct procedural service	Use when a separate, distinct procedure is performed on the same date that is not normally reported together.
`76`	Repeat procedure by same physician	Use when the cast application is repeated by the same physician during the same encounter.
`77`	Repeat procedure by another physician (not in provided list)	Not listed in input; excluded per rules.
`78`	Unplanned return to the operating/procedure room by the same physician following initial procedure (not common for simple cast)	Use if an unplanned return to procedure area occurs for cast revision under the same encounter.
`52`	Reduced services	(Note: listed once above) Duplicate entries avoided — use as above.
`22`	Increased procedural services	Use when the application required substantially greater work than typical (extensive manipulation or complicated molding) and documentation supports the increased complexity.
`59`	Distinct procedural service	(Note: listed above) Avoid duplication — see above.

Taxonomy Code	Specialty	Notes
`207K00000X`	Orthopedic Surgery	Orthopedic surgeons commonly apply and oversee casts for lower leg fractures.
`207L00000X`	Podiatry	Podiatrists may apply short-leg casts for ankle and distal tibia/fibula injuries.
`2080P0003X`	Emergency Medicine	Emergency physicians frequently perform initial cast application in the ED setting.
`163W00000X`	Nurse Practitioner	NPs in orthopedics or urgent care often apply casts under protocol.
`363A00000X`	Physician Assistant	PAs in orthopedics or emergency medicine commonly perform cast applications.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`S82.201A`	Unspecified fracture of shaft of right tibia, initial encounter for closed fracture	Tibial shaft fractures are commonly immobilized with a short-leg cast.
`S82.202A`	Unspecified fracture of shaft of left tibia, initial encounter for closed fracture	Left-sided tibial shaft fracture treated with short-leg cast.
`S82.401A`	Unspecified fracture of lateral malleolus of right fibula, initial encounter for closed fracture	Distal fibula (lateral malleolus) fractures often receive short-leg casting for immobilization.
`S82.402A`	Unspecified fracture of lateral malleolus of left fibula, initial encounter for closed fracture	Left lateral malleolus fracture commonly managed with below-knee cast.
`S93.401A`	Sprain of unspecified ligament of ankle, initial encounter	Severe ankle sprains with instability may be immobilized in a short-leg cast.
`S82.841A`	Other fracture of medial malleolus, right lower leg, initial encounter for closed fracture	Medial malleolus fractures frequently require short-leg casting for stabilization.
`S82.842A`	Other fracture of medial malleolus, left lower leg, initial encounter for closed fracture	Left medial malleolus fracture treated with cast immobilization.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`29405`	Application of short leg cast (below-knee)	Primary procedure code for application of a short-leg cast; used to immobilize fractures of the tibia/fibula or severe ankle sprains.
`20690`	Application of unna boot; includes debridement and dressing	May be used in the same clinical course for soft-tissue management or adjunctive immobilization techniques, though not typically billed on the same day as definitive cast application.
`29075`	Application of external fixator, distal tibia/fibula (temporary external fixation)	Performed when temporary stabilization using external fixation is required prior to or instead of casting in more severe fractures.
`99070`	Supplies and materials (except spectacles), non-covered items used in the patient’s treatment	Used to bill non-implant supplies associated with cast materials if payer allows separate supply reimbursement.
`11042`	Debridement, subcutaneous tissue (for wound management)	May be performed prior to casting if open wounds require debridement before immobilization.

CPT 29305: Hip Spica Body Cast for Trunk and One Leg Immobilization

CPT-29325-HIP-SPICA-BODY-CAST-APPLICATION

CPT 29325: Hip Spica / Trunk and Leg Body Cast Application

CPT-29345-LONG-LEG-CAST-APPLICATION-IMMOBILIZATION

CPT 29345: Long Leg Cast Application, Leg and Knee Immobilization

CPT-29355-LONG-LEG-AMBULATORY-CAST-APPLICATION

CPT 29355: Long Leg Ambulatory Cast Application

CPT-29358-LONG-LEG-BRACE-CAST-FEMUR-FRACTURE-IMMOBILIZATION

CPT 29358: Long Leg Brace-Type Cast for Femur Fracture

CPT-29365-CYLINDER-CAST-LEG-KNEE-IMMOBILIZATION-FRACTURE

CPT 29365: Cylinder Cast for Leg and Knee Immobilization

CPT-29425-LOWER-LEG-CAST-APPLICATION-TIBIA-FIBULA-ANKLE

CPT 29425: Lower Leg Cast Application for Tibia/Fibula Fracture or Severe Ankle Sprain

CPT-29435-WALKING-CAST-LOWER-LEG-TIBIA-FIBULA-FRACTURE

CPT 29435: Walking Cast for Tibia and Fibula Shaft Fractures

CPT-29440-REMOVABLE-WALKER-OR-HEEL-PAD-FOR-LEG-CAST

CPT 29440: Addition of Removable Walker or Heel Pad to Leg Cast

CPT-29445-TOTAL-CONTACT-WALKING-CAST-FOR-DIABETIC-ULCER-OFFLOADING

CPT 29445: Total Contact Walking Cast for Diabetic Foot Ulcer

Showing 1–10 of 11

References

1.CPT® Codes and Descriptions. AAPC. Retrieved Jul 29, 2026.
2.HCPCS Quarterly Update. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.
3.ICD-10-CM Full Code List. Centers for Medicare & Medicaid Services (CMS). Retrieved Jul 29, 2026.

Published by

Trek Health powers OpenPayer with a leading commercial payer intelligence platform, seamlessly converting fragmented payer data into actionable insights for provider organizations.

OpenPayer

CPT 29405: Short Leg Cast for Lower Leg Fracture or Severe Ankle Sprain

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Billing Code Overview

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CPT 29405: Short Leg Cast for Lower Leg Fracture or Severe Ankle Sprain

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Billing Code Overview

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References

Clinical & Coding Specifications

Clinical Context

Coding Specifications

Related Diagnoses

Related CPT Codes

Related Codes

References