ICD 10 Coding Alert

Know rigid or flexible, acquired or congenital, for accurate Dx documentation.

It's a common and all-too-painful condition. But because hammertoe can have different etiologies and manifestations, coding for it isn't always as straightforward as you'd think.

So, read through this guide to help set your hammertoe coding straight. And once you've learned how to code it correctly, keep reading to learn the exact code needed to document the surgery used to correct it.

Zero in on the Basics of Hammertoe

Your toes two through five have two joints, and hammertoe is a bend in the first joint closer to the foot, says M. Dolores Farrer, DPM, MBA, wound care consultant and owner of Owner of Lagniappe Wound Care Consultants, LLC in Columbia, South Carolina. This bend results in a curled position that resembles a hammer.

Causes:  Hammertoes usually develop over time due to tight shoes or arthritis, according to Farrer. Hammertoe can also develop from motor nerve damage that causes the ligaments and tendons to become unbalanced and curl the toes downward. Hammertoe is very common in diabetics with motor neuropathy.

A hammertoe can also develop when a bunion starts moving over laterally, to the outside of your foot, and then the second toe has to get out of the way and ends up on top of the big toe, Farrer adds. Feet with high arches also often develop hammertoes.

Diagnosing: Podiatrists diagnose hammertoe by performing a physical exam of the foot to study the contracture of the toes and using imaging techniques like X-rays to identify the degree of the deformity.

There are two types of hammertoes:

• Flexible hammertoe: If the patient's toe can still be moved at the joint, then it's a flexible hammertoe. This type is considered an earlier, milder form of the condition.
• Rigid hammertoe: If the tendons in the patient's toe have become rigid, then they will press the joint out of alignment and the toe can't move. Rigid hammertoe is considered more developed than flexible hammertoe.

Turn to These ICD-10 Codes for Acquired Hammertoe

Your ICD-10 options for acquired hammertoe include the following:

• M20.40 - Other hammer toe(s) (acquired), unspecified foot
• M20.41 - Other hammer toe(s) (acquired), right foot
• M20.42 - Other hammer toe(s) (acquired), left foot.

Caution: In the ICD-10 manual, an Excludes1 note for M20- lists the following codes you should never use at the same time as M20.40-M20.42:

• Acquired absence of fingers and toes (Z89.-)
• Congenital absence of fingers and toes (Q71.3-, Q72.3-)
• Congenital deformities and malformations of fingers and toes (Q66.-, Q68-Q70, Q74.-).

Note: If the patient's hammertoe is congenital, then you would report a code from category Q66- (Other specified congenital deformities of feet).

Expect to See These Treatment Options for Hammertoe

To treat hammertoe, there are some cushions, pads, and straps that the patient can use to protect the joint or pull down the toe when wearing a shoe, but these are only temporary solutions, Farrer says.

To fix hammertoe permanently the patient will need surgery, and for rigid hammertoe, surgery is the only possible treatment option. During the procedure, the surgeon will roughen up the cartilage on the base of the middle phalanx to promote arthrofibrosis, and the complex is then straightened and fixed with a K-wire.

"Most times the head of the proximal phalynx is removed," says Arnold Beresh, DPM, CPC, CSFAC in Newport News, Virginia. "The toe is not always fused with a K-wire. There are now many different implants to be used between the proximal and middle phalynx," he adds.

CPT^® code: When a podiatrist performs a flexible or rigid hammertoe correction, you can report this procedure with 28285 (Correction, hammertoe (eg, interphalangeal fusion, partial or total phalangectomy)).