Podiatry Coding & Billing Alert

Support repair code with other bone conditions for maximum benefit.

Your practice may come across many cases of chronic ankle pain, but you will need to keep your eyes peeled to differentiate them from an impingement syndrome such posterior tibial impingement also known as os trigonum syndrome in your podiatrist’s documentation. These tips will help you come out unscathed while reporting the posterior tibial impingement repair procedure.

Background: Posterior ankle impingement syndrome (PAIS) is a term used to describe a musculoskeletal disorder created from the repeated abutment of the posterior process of the talus or os trigonum between the tibia and calcaneus during plantar flexion of the ankle. When the os trigonum is the cause, it is described as os trigonum syndrome. Podiatrists might refer to this condition as os trigonum syndrome, talar compression syndrome, posterior ankle impingement (PAI) syndrome, or posterior tibiotalar impingement syndrome (PTTIS). 

Go to 28120 for Surgical Os Trigonum Repair

Mostly, your podiatrist will advise conservative treatment of ankle impingement syndromes. This will entail anti-inflammatory medication, activity modification, cast immobilization, physical therapy, shoe gear modifications, heel lifts and local corticosteroid injections. When conservative measures fail with the persistence of symptoms such as swelling, tenderness, limitation of motion and weakness, the podiatrist will consider surgical management to excise the small bone.

The primary goal of operative treatment for posterior ankle impingement is excision of the impeding anatomical structure. One should remove a fractured os trigonal or posterolateral talar process in its entirety. The podiatrist makes an incision behind the ankle, identifies the os trigonum, and dissects it free of its surrounding soft-tissue attachment. 

When you encounter a surgical excision, you can directly opt for a direct CPT® code 28120 (Partial excision [craterization, saucerization, sequestrectomy, or diaphysectomy] bone [e.g., osteomyelitis or bossing]; talus or calcaneus).

Watch out: As the os trigonum is an accessory bone and CPT® has no specific code for removing the same, check whether your payer will accept code 28120 in absence of osteomyelitis or other diseased bone conditions. You can then report code 28899 (Unlisted procedure, foot or toes). Make sure you include a detailed procedure note in your documentation explaining the excision of an accessory foot bone.

Make Sure Os Trigonum Excision Stands On Sound Diagnosis

You have coded the procedure right, but it may stand the test of payer scrutiny if the claim is not accompanied by accurate diagnosis codes. This is all the more important here since there is no direct and specific diagnosis code for os trigonum syndrome.

You will have to choose the ICD-9 code to match the clinical findings in the documentation. Mostly, you will be looking at codes such as 726.70 (Enthesopathy of ankle and tarsus, unspecified) or 726.71 (Achilles bursitis or tendonitis). Experts say one of the possible code for os trigonum may be 755.69 (Other congenital anomalies of lower limb including pelvic girdle). “I would use the ICD-9 code for accessory bone of the foot, which is 755.67 (Congenital anomalies of foot not elsewhere classified),” suggests Arnold Beresh, DPM, CPC, Peninsula Foot and Ankle Specialists PLC in Hampton, Va. The ICD-10 crosswalks for the given codes will be Q74.2 (755.69) and Q66.89 (755.67).

As os trigonum is usually excised because of symptoms related to fracture, your other non-specific options can also be fracture (closed) as ICD-9 codes 825.21, 825.20 (Fracture of unspecified bone[s] of foot [except toes], closed), or 825.29 (Other fracture of tarsal and metatarsal bones, closed). The ICD-10 equivalents to these codes are S92.109A, S92.909A, and S92.209A or S92.309A, respectively. Additionally, because pain and soft tissue inflammation are generally reported with os trigonum syndrome, you may want to add the secondary findings, signs, and/or symptoms of ICD-9 codes 729.5 (Pain in limb), 726.70 (Enthesopathy of ankle and tarsus, unspecified), 726.71 (Achilles bursitis or tendinitis), and/or 726.8 (Other peripheral enthesopathies). The ICD-10 crosswalks for these codes are respectively M79.609, M76.899 or M77.40, M76.60, and M77.8. Ensure that you match the ICD-9 code with the clinical findings, signs, and/or symptoms.

Get Max Mileage From Allied Repair Services

As the os trigonum impacts the tendon of the ankle, if the podiatrist reconstructs the patient’s tendon, you should code 28238 (Reconstruction [advancement], posterior tibial tendon with excision of accessory tarsal navicular bone [e.g., Kidner type procedure]).

You can also go for other tendon repair codes depending upon the exact procedure performed by the podiatrist. You can opt from 27690 (Transfer or transplant of single tendon [with muscle redirection or rerouting]; superficial [e.g., anterior tibial extensors into midfoot]), 27691 (... deep [e.g., anterior tibial or posterior tibial through interosseous space, flexor digitorum longus, flexor hallucis longus, or peroneal tendon to midfoot or hindfoot]), 28262 (Capsulotomy, midfoot; extensive, including posterior talotibial capsulotomy and tendon[s] lengthening [e.g., resistant clubfoot deformity]), 28730 (Arthrodesis, midtarsal or tarsometatarsal, multiple or transverse), or 28737 (Arthrodesis, with tendon lengthening and advancement, midtarsal, tarsal navicular-cuneiform [e.g., Miller type procedure]).

Note: Remember, payers consider 28238 a component of the tendon repair codes mentioned before and you cannot get paid separately for 28238 it if the podiatrist did any of these five procedures.

Code it yourself: The podiatrist attends to a patient with chronic plantar fascial pain in the right foot and a chronic posterior right ankle pain, secondary to os trigonum. The podiatrist decides to opt for surgical intervention after the patient’s lack of response to conservative treatment. The podiatrist documents the diagnosis as painful chronic plantar fasciitis, heel spur syndrome, right and painful accessory bone, posterior aspect of the right subtalar joint, posterior os trigonum syndrome due to a severe ankle injury. The podiatrist performs an excision of os trigonum, posterior aspect of the right subtalar joint and a plantar fascial release, heel spur excision, open, right.

To report the procedure, you would bill two codes in your claim: 

• 28120-59-RT

• 28119-51-RT (Ostectomy, calcaneus; for spur, with or without plantar fascial release)

Don’t forget your diagnosis code for os trigonum 755.69 or 755.67 to support 28120, and which you should base on medical findings and symptoms.