HCPCS code L1720 – Tachdjian trilateral Legg-Perthes orthosis

Key takeaways

HCPCS code L1720 bills a custom-fabricated trilateral Legg-Perthes orthosis of the Tachdjian type, a pediatric brace for Legg-Calvé-Perthes disease.

The code is always custom fabricated, so an off-the-shelf or prefabricated hip brace can never be billed under it.

Valid diagnosis pairings sit in the M91 series, with M91.11 or M91.12 expected once imaging names the affected hip.

L1720 is on the CMS DMEPOS Master List but not on the required prior authorization or written-order-before-delivery lists.

Every code from L1700 to L1755 treats the same disease, so the brace design in the fitting note decides which one you bill.

HCPCS code L1720 covers the Tachdjian trilateral Legg-Perthes brace

HCPCS code L1720 is the Level II code for a trilateral Legg-Perthes orthosis of the Tachdjian type, custom fabricated. It bills a one-leg brace built for a child with Legg-Calvé-Perthes disease.

The code sits in the L-code series of the CMS HCPCS Level II system. Payers handle it as Durable Medical Equipment, Prosthetics, Orthotics, and Supplies, known as DMEPOS.

The design is what the code describes. Billing L1720 for any other Legg-Perthes brace is a coding error, even when the diagnosis is identical. Billing it for an adult hip brace is a bigger one. L1720 describes a pediatric device, unrelated to hip replacement or osteoarthritis.

Official descriptor and device specifications

The official descriptor reads: Legg perthes orthosis, trilateral, (tachdijan type), custom fabricated. The CMS files misspell the surgeon’s name, Mihran Tachdjian, so search by the code number rather than by the name. Confirm the wording against the current CMS HCPCS annual release file before each coding year.

The Tachdjian orthosis is worn on the affected leg only. A plastic trilateral socket at the top of the thigh carries body weight through the ischial tuberosity, so the femoral head is unloaded. A single medial upright with a knee lock runs down to a stirrup fixed to the shoe.

The brace holds the hip in about 30 degrees of abduction or more, with internal rotation. The opposite shoe carries a lift to level the pelvis. Those figures come from the original description by Tachdjian and Jouett, published in 1968.

Custom fabricated, never off the shelf

A custom-fabricated orthosis is built from raw materials over a cast, model, or measurements of one patient. An off-the-shelf device comes in set sizes and needs only minor adjustment. No prefabricated version of the Tachdjian brace has its own HCPCS code.

All five codes in the L1700-L1755 range are custom fabricated, so fabrication method never separates them. The fitting note has to name the trilateral Tachdjian design, and the fabrication records have to show the brace was built for this child.

What L1720 covers and what it excludes

L1720 covers one complete custom-fabricated Tachdjian brace, including the socket, the upright, the knee joint, and the shoe attachment. It does not cover:

• Off-the-shelf or prefabricated hip braces: a prefabricated postoperative hip abduction orthosis bills under L1686, not L1720.
• Adult postoperative hip braces: a custom-fabricated postoperative hip abduction orthosis bills under L1685.
• Dynamic hip abduction orthoses: the Rancho hip action type with pelvic control and thigh cuffs bills under L1680.
• Other Legg-Perthes designs: Toronto, Newington, Scottish Rite, and patten-bottom braces each have their own code.
• Adult hip diagnoses: osteoarthritis, an artificial hip joint, or hip dislocation do not support this pediatric brace.

The shoe lift on the opposite side is part of how the brace works. Check the payer’s policy before billing it as a separate item.

Why a child with Legg-Calvé-Perthes disease needs this brace

Legg-Calvé-Perthes disease interrupts the blood supply to the femoral head in a growing child. The bone softens, then remodels as that supply returns.

Treatment aims to keep the femoral head seated in the acetabulum through the remodeling, so it heals round rather than flattened. The condition mostly appears between ages 4 and 10, and boys are affected around four times as often as girls.

The Tachdjian design does two jobs at once. Abduction and internal rotation contain the femoral head, and the ischial socket takes weight off it. The child keeps walking, which a hip spica cast would not allow.

That clinical aim is also the billing argument. The physician note has to name the diagnosis, the disease stage, the affected side, and why containment with unloading suits this child.

L1720 coverage criteria

Medicare covers L1720 under the orthotics benefit when a physician documents that the brace is medically necessary. No national coverage determination is written for Legg-Perthes orthoses.

Medicare DMEPOS claims go to one of two DME MAC contractors, based on where the beneficiary lives. Noridian handles Jurisdictions A and D, and CGS Administrators handles Jurisdictions B and C across the rest of the country. Check the Medicare Coverage Database for any policy article your contractor publishes on hip or Legg-Perthes orthoses.

Medicare is rarely the payer here. Legg-Calvé-Perthes disease is a pediatric condition, so most L1720 claims go to a state Medicaid program or a commercial plan. Confirm the policy and any approval step before the brace is fabricated.

Where the L1720 payment rate comes from

Medicare pays L1720 from the DMEPOS fee schedule, which CMS updates every January 1. The Physician Fee Schedule does not carry orthotic L-codes, so a search there returns no rate.

Pull the current allowable from the CMS DMEPOS fee schedule files for the beneficiary’s state. Three points shape what you are paid:

• Purchase, not rental: a custom-fabricated brace is made for one patient, so it is billed as a purchase.
• Regional variation: fee schedule amounts differ by state and between rural and non-rural areas.
• Assignment: participating suppliers accept assignment and cannot bill the family above the allowed amount.

Medicaid and commercial rates follow each program’s own fee schedule. Check them with the payer before quoting a figure to the family.

Only M91 diagnosis codes support an L1720 claim

The crosswalk is narrow. Valid pairings sit in the M91 series, which covers juvenile osteochondrosis of the hip and pelvis. Legg-Calvé-Perthes disease itself codes to M91.1x, juvenile osteochondrosis of the head of the femur. Documented pelvic involvement codes to M91.0 instead.

Adult hip codes do not belong on this claim. Osteoarthritis (M16.1x), an artificial hip joint (Z96.64x), or a hip dislocation will not support a pediatric Legg-Perthes brace.

Check laterality on every L1720 claim. The Tachdjian brace is built for one leg, so the side of the diagnosis should match the side of the brace. Take the side from the radiology report and the physician order, then code it.

L1720 documentation requirements

The claim itself is a few lines. The record behind it is what gets paid, or recovered at audit. Keep these documents in the patient file:

• Standard written order: patient name, order date, device description, quantity, and the treating practitioner’s name, NPI, and signature.
• Medical necessity notes: the LCP diagnosis, the disease stage, the affected side, the child’s age, and the reason for containment and unloading.
• Fabrication and fitting records: measurements, the cast or model used, the trilateral Tachdjian design, and each adjustment the orthotist made.
• Proof of delivery: a signed and dated receipt confirming the family received the brace.
• Supplier qualifications: enrollment and accreditation certificates held on file under the DMEPOS supplier standards.

CMS requires the written order before the claim is submitted. The CMS Master List entry for L1720 does not place it on the face-to-face and written-order-before-delivery list. That list changes, so check the current DMEPOS order requirements.

A medical-necessity review looks for age, stage, and side in the physician’s note, not only the orthotist’s. Timing matters as well, because the payer check comes before fabrication and the order before the claim. The timeline below puts each record in sequence.

Modifiers used with L1720

L1720 needs few modifiers. Report the side, and add a liability modifier only when coverage is in doubt.

An Advance Beneficiary Notice, or ABN, protects the supplier when Medicare may deny the brace as not reasonable and necessary. Issue it before delivery and keep the signed copy in the patient file.

Neighboring HCPCS codes in the L1700-L1755 range

Every code in the range treats the same disease. They differ only by brace design, which makes the choice a documentation question rather than a clinical one. A Newington-type brace for the same child bills under L1710, for example.

All five are custom fabricated, so that phrase never tells you which code to use. Read the fitting note, find the design name, then match it. The sibling guides to HCPCS code L1730 and HCPCS code L1755 cover the Scottish Rite and patten-bottom braces.

Common reasons L1720 claims are denied

Most L1720 denials trace back to a missing or mismatched document in the supplier’s own file. The table maps the usual triggers to their fixes.

When a claim does deny, the remittance tells you which element failed. Reading the medical billing denial codes on the response saves a blind resubmission. The CARC and RARC pair names the missing element.

Run this check before you submit

• Standard written order signed and dated, and on file before the claim goes out.
• Physician note names the Legg-Calvé-Perthes diagnosis, the disease stage, the affected side, and the child’s age.
• Diagnosis code is from the M91 series and carries laterality wherever imaging identified the affected hip.
• Fitting record names the trilateral Tachdjian design and the measurements taken.
• Signed proof of delivery is filed against the patient record.
• Payer confirmed, because most of these children are covered by Medicaid or a commercial plan.

A clear superbill helps when a family has to claim from an out-of-network plan themselves. It carries the code, the diagnosis, the date of service, and the charge.

Where Pabau fits into an L1720 claim

Orthotic billing usually fails on assembly. The order sits in one system and the fitting note in another. The delivery receipt sits in a drawer, and the claim goes out before anyone links them.

Pabau, the practice management platform we build, keeps those records on one patient file. Clinical notes, consent, fitting documentation, and delivery confirmation live on the record the billing team works from.

Claims then go out from that record through Pabau’s claims management, and each one is tracked through to payment. Code, modifier, and diagnosis choices stay with your coders.

Keep every L1720 record on one patient file

Pabau holds clinical notes, orders, fitting records, and delivery confirmations on one patient record. The claim then goes out from that record, so your team stops rebuilding files at audit time.

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Conclusion

L1720 describes one pediatric brace: a custom-fabricated, one-leg Tachdjian orthosis for Legg-Calvé-Perthes disease. It pairs with one family of diagnosis codes, and it has no off-the-shelf version.

The claims that fail usually fail on design or sequence. Name the trilateral design in the fitting note and the side in the diagnosis. File the order and the delivery receipt before billing, and most of these claims pay on first submission.

Book a demo to see how Pabau keeps orthotic documentation and claim submission on one patient record.

Continue your research

Need to understand the full DMEPOS billing process? What is medical billing covers the end-to-end workflow from claim creation to payment posting.

Dealing with claim denials on orthotic codes? Denial management in healthcare explains how to analyze CARC codes, build an appeals workflow, and track denial rates by payer.

Managing billing compliance across a multi-provider practice? Medical billing compliance outlines the documentation standards and internal audit steps that protect DMEPOS suppliers from post-payment recovery.

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