M21.27 Flexion deformity, ankle and toes

ICD-10-CM Diagnosis Code M21.27: Flexion Deformity, Ankle and Toes

ICD-10-CM code M21.27 represents a flexion deformity of the ankle and toes, classified under the broader parent category of flexion deformities. The terminology record is active and does not contain narrower concepts. Clinical literature notes that ankle equinus involves limited dorsiflexion and can impact gait and mobility. 1 2

Plain-language overview

ICD-10-CM code M21.27 carries the preferred name flexion deformity, ankle and toes, and its semantic type is designated as an anatomical abnormality within the terminology system. 1

What this code represents

The diagnosis code M21.27 represents a flexion deformity of the ankle and toes, and this specific terminology record does not list any narrower subordinate concepts beneath it. 1

Coding details

Code M21.27 is a child of the parent concept M21.2, which is the general category for flexion deformities in the ICD-10-CM coding hierarchy, and the record status is active. 1

Code M21.27 expands into laterality-specific codes, including M21.271 for the right ankle and toes, M21.272 for the left ankle and toes, and M21.279 for an unspecified ankle and toes. 4

Clinical context

Ankle equinus describes a position of limited dorsiflexion, and this condition can significantly impact a patient's gait and mobility during both stance and swing phases. 2

Ankle equinus can result from osseous limitations, neuromuscular disorders, or soft tissue contractures, including overtightening of the gastrocnemius-soleus complex. 2

Documentation considerations

Clinical documentation for ankle equinus describes a clinical diagnosis where patients may present with varying degrees of deformity, and no specific degree of dorsiflexion loss is defined for diagnosis. 2

What the sources add

While the terminology record establishes the formal code hierarchy and active status, the clinical literature provides operational context regarding the functional impact and underlying mechanisms of ankle equinus. 1 2

Sources

1. ICD-10-CM M21.27 terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-27.
3. M21.27 - Flexion deformity, ankle and toes | ICD-10-CM — unboundmedicine.com; accessed 2026-07-27.
4. M21.27 — medcode.ch; accessed 2026-07-27.