Skip to content
HCC Buddy home

M08.959 ICD-10-CM Code: Juvenile arthritis, unspecified, unspecified hip

M08.959 maps to CMS-HCC V28 93. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · HCC coding software

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

FY 2026 Apr update / Diseases of the musculoskeletal system and connective tissue (M00-M99) / Inflammatory polyarthropathies (M05-M14)

M08.959

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Juvenile arthritis, unspecified, unspecified hip

A type of arthritis that develops in children affecting the hip, but the specific hip (left or right) is not documented or is bilateral.

Buddy the Bee presenting code insight

Buddy Insight

Juvenile arthritis affecting the hip represents a significant chronic inflammatory condition that can impact mobility, growth, and quality of life in pediatric patients.

CMS-HCC V28

HCC 93

Code-level coefficient reference

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 056

Code-level coefficient reference

ESRD/PACE

HCC 40

Code-level coefficient reference

RXHCC

HCC 83

Code-level coefficient reference

Code Book Path

Official
M08.9Juvenile arthritis, unspecified
M08.95Juvenile arthritis, unspecified, hip
M08.959Juvenile arthritis, unspecified, unspecified hip

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for M08.959 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for M08.959 in this effective period.

Related Child Codes

Official
M08.951Juvenile arthritis, unspecified, right hip
M08.952Juvenile arthritis, unspecified, left hip

Includes

Official

ICD-10-CM does not list Includes notes for M08.959 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for M08.959 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for M08.959 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for M08.959 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for M08.959 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Patient age at onset (must be under 16 years old)
Evidence of chronic arthritis lasting at least 6 weeks
Hip joint involvement with inflammatory signs
Exclusion of other causes of arthritis

MEAT Support

HCC Buddy guidance
Patient age at onset (must be under 16 years old)
Evidence of chronic arthritis lasting at least 6 weeks
Hip joint involvement with inflammatory signs
Exclusion of other causes of arthritis

Audit Caution

HCC Buddy guidance
Failing to verify patient age at onset was under 16 years
Using this code when laterality is documented in the record
Coding acute arthritis without evidence of chronicity (6+ weeks)
Not distinguishing from other forms of juvenile arthritis when type is specified

Common Mistakes

HCC Buddy guidance
M08.951/M08.952 — Use when laterality (right/left hip) is specified
M08.00-M08.09 — Unspecified juvenile rheumatoid arthritis with specific joint involvement
M08.20-M08.29 — Juvenile rheumatoid arthritis with systemic onset
M25.551/M25.552 — Pain in hip, not inflammatory arthritis

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is M08.959 an HCC code?

Yes. M08.959 (Juvenile arthritis, unspecified, unspecified hip) maps to HCC 93, Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.617. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: M08.959 is billable and maps to V28 HCC 93, Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
M08.959
Description
Juvenile arthritis, unspecified, unspecified hip
HCC (V28)
HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders
RAF reference coefficient
0.617
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 93, Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders
0.617
ESRDHCC 40, Rheumatoid Arthritis and Inflammatory Connective Tissue Disease
Not separately weighted
RxHCCHCC 83, Rheumatoid Arthritis and Other Inflammatory Polyarthropathy
Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work M08.959 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for M08.959

For M08.959 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

  • MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
  • EEvaluate: test results, medication response, or physical findings reviewed by the provider
  • AAssess: explicit mention in the assessment or plan with acknowledgment of status
  • TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed M08.959 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

Get the V28 mapping + MEAT cheat sheet

One printable reference: check representative V28 mappings and the documentation reminders your note needs. Free, no card.

Free PDF. No card. Unsubscribe anytime.

What This Code Means

M08.959 is the ICD-10-CM diagnosis code for juvenile arthritis, unspecified, unspecified hip. A type of arthritis that develops in children affecting the hip, but the specific hip (left or right) is not documented or is bilateral. M08.959 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering inflammatory polyarthropathies (m05-m14).

Under the CMS-HCC V28 risk adjustment model, M08.959 maps to Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders (HCC 93) with a source-labeled community, non-dual, aged reference coefficient of 0.617. No V24 mapping is shown for M08.959; use the applicable model and payment year when reviewing the V28 mapping. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Use this code only when laterality cannot be determined from the medical record. Because M08.959 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for M08.959 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Use this code only when laterality cannot be determined from the medical record
  • •If both hips are affected, code both M08.951 and M08.952 instead of using the unspecified code

Clinical Significance

Juvenile arthritis affecting the hip represents a significant chronic inflammatory condition that can impact mobility, growth, and quality of life in pediatric patients. This diagnosis requires ongoing monitoring and specialized care to prevent joint damage and functional impairment.

Documentation Requirements

  • ✓Patient age at onset (must be under 16 years old)
  • ✓Evidence of chronic arthritis lasting at least 6 weeks
  • ✓Hip joint involvement with inflammatory signs
  • ✓Exclusion of other causes of arthritis
  • ✓Functional assessment and mobility evaluation
  • ✓Current treatment regimen and response
  • ✓Joint imaging studies (X-ray, MRI, or ultrasound)
  • ✓Laboratory results if available (ESR, CRP, ANA)

Commonly Confused Codes

  • •M08.951/M08.952: Use when laterality (right/left hip) is specified
  • •M08.00-M08.09: Unspecified juvenile rheumatoid arthritis with specific joint involvement
  • •M08.20-M08.29: Juvenile rheumatoid arthritis with systemic onset
  • •M25.551/M25.552: Pain in hip, not inflammatory arthritis
  • •M16.0-M16.9: Osteoarthritis of hip, typically in adults

Child Codes

M08.951Juvenile arthritis, unspecified, right hip
HCC 93
M08.952Juvenile arthritis, unspecified, left hip
HCC 93
M08.959Juvenile arthritis, unspecified, unspecified hip
HCC 93

Code Hierarchy

└M08Juvenile arthritis└M08.9Juvenile arthritis, unspecified└M08.95Juvenile arthritis, unspecified, hip└M08.959Juvenile arthritis, unspecified, unspecified hip
└M08.959Juvenile arthritis, unspecified, unspecified hip

Because M08.959 maps to an HCC category, the documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment.

M08.959 maps to CMS-HCC V28 category 93, Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for M08.959. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

Work M08.959 in HCC Buddy

Open M08.959 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

Open in Code BookOpen in EncoderStart Pro