M89.121 Complete physeal arrest, right proximal humerus

ICD-10-CM Code M89.121: Complete Physeal Arrest, Right Proximal Humerus

ICD-10-CM code M89.121 identifies a complete physeal arrest located in the right proximal humerus. The available public sources establish this specific code through a Medicare billing article and provide clinical context regarding physeal injuries. A physeal growth arrest with a consecutive bone bridge can occasionally occur after an injury of the proximal humeral physis. 2 3

Plain-language overview

A physeal growth arrest with a consecutive bone bridge can occasionally occur after an injury of the proximal humeral physis. The available sources do not provide a plain-language definition of the physis or explicitly state the physiological meaning of a complete arrest. 2

What this code represents

Code M89.121 represents the diagnosis of complete physeal arrest in the right proximal humerus. A Centers for Medicare and Medicaid Services billing article lists this code alongside distinct codes for the left proximal humerus and for partial physeal arrest. 3

Coding details

The Centers for Medicare and Medicaid Services article explicitly lists M89.121 for complete physeal arrest of the right proximal humerus, M89.122 for the left proximal humerus, and M89.123 for partial physeal arrest of the right side. The sources do not provide further category hierarchy or billable specificity guidelines. 3

Documentation considerations

The available sources do not explicitly state the documentation elements needed to assign code M89.121. The Centers for Medicare and Medicaid Services article distinguishes M89.121 from codes for the left side and for partial physeal arrest, but it does not outline specific clinical documentation rules. 3

Clinical context

Epiphyseal injuries of the proximal humerus are documented as the most common injuries of the shoulder and upper arm among adolescents. The clinical source notes that physeal injuries of the proximal humerus requiring surgery occur at an average age of 11.8 years. 2

A study of open reduction for proximal humerus fractures in adolescents included patients with open proximal humeral physes. The study evaluated clinical and radiological outcomes to determine the incidence of physeal damage in patients who undergo operative treatment. 1

What the sources add

The clinical literature source adds context about physeal injuries and growth arrest, while the Centers for Medicare and Medicaid Services source provides the specific administrative code M89.121. These sources establish the clinical background and the official billing label separately. 1 2 3

Coverage and utilization context

The Centers for Medicare and Medicaid Services article includes M89.121 in a billing and coding context for sedimentation rate testing. The source text does not explicitly state that inclusion indicates its use in administrative claims processing, nor does it state that inclusion does not guarantee coverage for any specific service. 3

Sources

1. Open reduction of proximal humerus fractures in the adolescent population — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
2. Physeal injuries of the proximal humerus: long-term results in seventy two patients — pmc.ncbi.nlm.nih.gov; accessed 2026-07-25.
3. Article - Billing and Coding: Sedimentation Rate, Erythrocyte (A57657) — cms.gov; accessed 2026-07-25.