Application of a patellar tendon-bearing cast to the lower leg, allowing knee flexion while immobilizing the foot and ankle for tibia or fibula shaft fracture management.

Verified May 8, 2026 · 5 sources ↓

Medicare: $139.28
Work RVU: 1.15
Global, days: 0
Region: Foot & ankle

Drawn from CMSAAPCFindacodeWcb

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 5 cited references ↓

Specify 'patellar tendon-bearing cast' by name — generic 'short leg cast' documentation will not support 29435
Document the clinical indication: fracture location (tibia/fibula shaft), laterality, and fracture stability status
Record that the knee is positioned to allow flexion, confirming the PTB design was applied
Note the date of application and the provider who applied the cast
If a same-day E/M is billed, document the separately identifiable decision-making that warrants modifier 25
For workers' comp and state fee schedule claims, confirm documentation meets payer-specific requirements per applicable state guidelines

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

25 Significant separate E/M 50 Bilateral procedure 52 Reduced services 76 Repeat, same physician 77 Repeat, another physician LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 5 cited references ↓

CPT 29435 covers the application of a patellar tendon-bearing (PTB) cast — a below-knee cast designed to offload weight through the patellar tendon and proximal tibia, freeing the knee to flex while stabilizing the distal leg and foot. It's used in functional fracture bracing for tibial shaft fractures, typically after initial swelling has resolved and the fracture has achieved early stability. The PTB cast is a specific construct distinct from a standard short leg cast (29405) or walking cast (29425); the design intent and bearing surface must be documented to support the code.

The global period is 000, meaning no pre- or post-operative visits are bundled. Any E/M service on the same date as cast application requires modifier 25 to demonstrate a separately identifiable evaluation. Because this is a casting code — not a fracture care code — 29435 does not include fracture reduction or manipulation. If closed reduction is performed the same day, that procedure is billed separately under the appropriate fracture care code.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU vs. total RVU

The work RVU (1.15) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (4.17) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	1.15
Practice expense RVU	2.78
Malpractice RVU	0.24
Total RVU	4.17
Medicare national rate	$139.28
Global period	0 days

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Setting	Medicare rate (national)
Office (PFS non-facility) Procedure performed in physician's office	$139.28
HOPD (APC 5102) Hospital outpatient department	$285.75
ASC (PI P3) Ambulatory surgical center (freestanding)	$93.65

Common denial reasons

The recurring reasons claims for CPT 29435 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Operative note or procedure note says 'short leg cast' without specifying the patellar tendon-bearing design, triggering downcoding to 29405
Same-day E/M denied for missing modifier 25 when cast application and office visit are billed together
Laterality not specified — some payers require LT or RT on lower extremity casting codes
Fracture care code and 29435 billed same-day without supporting documentation that they represent distinct, separately billable services
Place of service mismatch — HOPD and ASC payment rates differ substantially; billing under the wrong POS causes payment discrepancy

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01What separates 29435 from a standard short leg cast code like 29405?

The PTB cast is engineered to transfer weight-bearing load through the patellar tendon and proximal tibial flare, keeping the knee mobile. A standard short leg cast (29405) makes no such design provision. You must document the PTB construct explicitly — if the note just says 'short leg cast,' expect downcoding.

02Can I bill 29435 and a fracture care code on the same date?

Yes, if they represent distinct services. Fracture care codes (e.g., 27750 for closed tibial shaft fracture without manipulation) include cast application in their global package, so billing 29435 separately on the same date as a fracture care code will trigger bundling edits unless the cast is a subsequent application, not the initial treatment cast.

03Do I need modifier LT or RT for 29435?

CMS does not mandate laterality modifiers on casting codes, but many commercial payers and state workers' comp fee schedules do. Appending LT or RT is low-risk and prevents denials from payers that require it.

04Is modifier 50 appropriate if both legs need PTB casts?

Bilateral application of PTB casts is clinically rare, but if it occurs, report 29435 with modifier 50 for Medicare. Some commercial payers want two line items with LT and RT instead. Check payer policy before submitting.

05The global period is 000 — what does that mean practically?

A 000-day global means only the day of the procedure is bundled. Any visit the next day or later is billable separately. A same-day E/M still needs modifier 25 to get paid alongside the cast application.

06Can a PA or NP apply the cast and bill under 29435?

Yes, provided scope-of-practice laws in your state allow it and the supervising physician arrangement meets payer requirements. Bill under the performing provider's NPI with the appropriate supervision level documented. Some payers require the supervising physician's NPI as well.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira Scribe

Mira's AI scribe captures the cast type by name ('patellar tendon-bearing cast'), the bearing surface design, knee position, laterality, and the fracture indication from dictation. It flags notes that use generic language like 'short leg cast' without PTB specificity — the most common reason 29435 gets downcoded to 29405 on audit. If an E/M is dictated the same day, the scribe prompts for modifier 25 documentation to protect that charge.

See how Mira captures CPT 29435 documentation