S86.009A Unspecified injury of unspecified Achilles tendon, initial encounter

ICD-10-CM Code S86.009A: Unspecified injury of unspecified Achilles tendon, initial encounter

ICD-10-CM code S86.009A identifies an unspecified injury of an unspecified Achilles tendon during an initial encounter. The Centers for Medicare & Medicaid Services lists this exact code and description in a billing and coding article. Clinical literature describes Achilles tendon issues as painful overuse injuries or acute ruptures, establishing the clinical background for this diagnosis. 1 2 3

Plain-language overview

Achilles tendinopathy is a painful overuse injury of the Achilles tendon that presents with localized pain, swelling, and loss of function, while acute Achilles tendon rupture represents a distinct injury category with an estimated incidence ranging from 11 to 37 per 100,000 population. 1 2

What this code represents

The Centers for Medicare & Medicaid Services identifies S86.009A as Unspecified injury of unspecified Achilles tendon, initial encounter, and also lists S86.009D for a subsequent encounter for the same unspecified injury. 3

Documentation considerations

Clinical evaluation of Achilles tendinopathy involves assessing a combination of localized pain, swelling of the Achilles tendon, and loss of function to establish the diagnosis, and pain on palpation of the tendon is a reliable test for diagnosing midportion Achilles tendinopathy. 1

Documenting an acute Achilles tendon rupture involves recognizing a bimodal age distribution with a first peak in patients between 25 and 40 years of age and a second peak in those over 60, with high-energy sports injuries responsible for the first peak. 2

What the sources add

The CMS source provides the exact alphanumeric code and official description for billing purposes, whereas the clinical literature from PMC provides the underlying clinical concepts of Achilles tendinopathy and acute rupture that inform the medical documentation. 1 2 3

Coverage and utilization context

The Centers for Medicare & Medicaid Services includes the S86.009A diagnosis code within an article titled Billing and Coding: Routine Foot Care, demonstrating its administrative appearance in payer guidance. 3

Clinical context

Achilles tendon rupture accounts for 20% of all large tendon ruptures, and men are 2 to 12 times more prone to Achilles tendon rupture than women, with a mean age of 39.8 years at the time of injury among 826 analyzed patients. 2

Achilles tendinopathy is not purely an athletic injury, given that 65% of injuries diagnosed in a general practice setting are not sport related, and approximately 30% of patients have bilateral pain. 1

Sources

1. Current Clinical Concepts: Conservative Management of Achilles Tendinopathy — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
2. Treatment of Acute Achilles Tendon Rupture — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
3. Article - Billing and Coding: Routine Foot Care (A56680) — cms.gov; accessed 2026-07-25.