Take These 5 Steps to Get the Digits Right and Code Hammertoes
Learn which modifiers to append to your claim. A hammertoe is a deformity of a lesser toe — most often the second, third, or fourth — where the middle joint bends abnormally, causing the toe to curl downward like a claw or hammer. This usually develops due to a chronic imbalance between the muscles and tendons in the foot, which can be exacerbated by ill-fitting footwear. Over time, the abnormal pull on the joint can lead to pain, corns, calluses, and even difficulty walking, making what seems like a minor problem a major disruption to daily life. Hammertoes are deceptively complex from a coding standpoint. What looks like a simple toe surgery can involve multiple structures, multiple toes, and multiple codes. Accurate coding is essential for demonstrating medical necessity, obtaining prior authorization, and ensuring full reimbursement — especially when more than one toe is treated. Understanding Hammertoes Is the First Step Hammertoe symptoms often start subtly. Patients may notice an abnormal bend in the middle joint, followed by pain on the toe tip, knuckle, or ball of the foot. As the toe rubs against shoes, corns and calluses can form, further increasing discomfort. Wearing shoes — especially tight, narrow shoes, or high heels — becomes painful and, in more advanced cases, the toe becomes rigid and claw-like, permanently locked in its curled position. Several factors can contribute to hammertoes. Chronic pressure from tight shoes, structural predispositions like a long second toe or high arches, and muscle or tendon imbalance are common culprits. Arthritis can also damage joints and accelerate deformity. Treatment ranges from conservative to surgical. Early intervention often involves wider, softer shoes, padding, or splints to reduce pressure and allow the toe to move freely. When conservative care fails or the deformity becomes fixed and painful, surgical correction may be needed to realign or fuse the joint. Step 1: Nail Down the Diagnosis The ICD-10-CM code set features the following codes for hammertoe: Always document which toe and which foot is affected. Specificity is your shield against denials. While M20.40 exists, it’s rarely appropriate to report the code. If the laterality isn’t documented, your claim will be vulnerable to denials. Also, remember that hammertoes often come with corns or callosities, which are coded with L84 (Corns and callosities) or even ulcerations, coded with the L97.- (Non-pressure chronic ulcer of lower limb, not elsewhere classified) code category. If those conditions are treated at the same encounter, code them as well. These added diagnoses often strengthen medical necessity. Step 2: Hammer in the Correct CPT® Code Hammertoe procedures can range from minor tendon releases to complex bony reconstructions. The correct code selection depends on which structure was addressed, the approach, and which toe was operated on. Below are procedure codes for bony procedures: Procedures performed on soft tissues include: You’ll notice that 28011’s descriptor includes the phrase “multiple tendons.” This means that the code is appropriate when the physician operates on multiple tendons in the same toe — not if the provider operates on multiple tendons in multiple toes. If the podiatrist treats tendons in two different toes, then you’ll report 28010 or 28011 for each toe appended with the appropriate T modifiers. You’ll also append modifier 59 (Distinct procedural service) or XS (Separate structure, a service that is distinct because it was performed on a separate organ/structure) as needed. Beware NCCI edits: Open or percutaneous tenotomies on the same toe in the same surgical field as a hammertoe correction are typically bundled together, according to the National Correct Coding Initiative (NCCI) edits. For example, 28010 is listed as a column 2 code for 28285, which means you will only report 28285 if the physician performs hammertoe correction and a percutaneous tenotomy on the same toe during the same session. Make sure to check NCCI edits before reporting the procedures separately. Additionally, these codes carry a 90-day global period. You need to factor in this time period when or if to report post-op procedures. Step 2.5: Tackle Toe Modifiers Payers want to know exactly which toe was treated. T modifiers often replace RT (Right side) and LT (Left side) modifiers for toe procedures, especially under Medicare. Here’s a look at the different toe modifiers: Left foot: Right foot: Add a T modifier to every claim line for most payers. Other payers will accept four modifiers per line, in which case, you would change the units to 4. However, if your payer requires you to report additional toes as separate services, append 59 or XS on the second and subsequent toes. Step 3: Make Sure the Documentation Stands Up The podiatrist should document their encounter accurately and with the details you’ll need to report the appropriate codes for reimbursement. For example, the documentation needs to specify the toe or toes affected and treated as well as which feet were affected. The documentation should clearly indicate the procedure performed, as well as the reason for the treatment, such as chronic pain, deformity, or failed conservative care. Look for technical details that specify incisions, body structures addressed, whether fixation was used, and the type of closure. Lastly, the documentation should dictate each toe’s work separately if the provider is seeking reimbursement for treatment on more than one toe. Step 4: Think Ahead to Maintain Compliance Make sure you and your providers are taking the necessary actions to maintain compliance. These actions can include obtaining prior authorization, which is often required for procedures. Prior authorization needs to include ICD-10-CM and CPT® codes. The provider should also document risks, such as comorbidities like diabetes or peripheral artery disease (PAD) that elevate risk. Additionally, with clean, CPT®-aligned operative notes, the physician can ensure the coding and billing team will be ready in the event of an audit. The operative notes should be written in a way that assumes the reader is unfamiliar with the procedure they are reading. Step 5: Make a Quick Reference Chart Make a chart for common procedures, modifiers, and diagnoses that you can easily reference while moving through your workflow. Of course, double-check your code selections against the CPT® and ICD-10-CM code books to ensure you’re assigning the most appropriate codes for the services provided and documented diagnoses. Below is an example of a quick reference chart: Bony procedures: 28285, 28270, 28126 — Arthrodesis/Arthroplasty/fusion/phalangectomy Soft tissue procedures: 28272, 28232, 28234, 28010, 28011 — Capsulotomy or tenotomy ICD-10-CM: M20.41, M20.42, M20.40 — Hammertoe (by laterality); add L84 or L97, if applicable Toe modifiers: TA-T4 (L), T5-T9 (R) Other modifiers: 59/XS Final Thoughts Coding hammertoes isn’t just about choosing a code — it’s about telling the full clinical story. Documenting which toe, what structures, and why the procedure was performed builds a claim that’s clean, defensible, and audit-ready. When done well, the provider’s documentation shows payers not just what was done, but why it mattered — and that’s how your podiatrist gets paid fairly for their work, one toe at a time. Tonia Silva, CPC, CPMA, CPPM, Contributing Writer
