A50.51 ICD-10-CM Code: Clutton's joints
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FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Infections with a predominantly sexual mode of transmission (A50-A64)
A50.51
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceClutton's joints
Clutton's joints is a painless swelling of the knees and other large joints that occurs in children with congenital syphilis. This condition results from inflammation caused by syphilis infection passed from mother to child before birth.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
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Inclusion Terms
Official- Any congenital syphilitic condition specified as late or manifest two years or more after birth.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for A50.51 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for A50.51 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for A50.51 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for A50.51 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for A50.51 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for A50.51 in this effective period.
Buddy Documentation Tip
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is A50.51 an HCC code?
No. A50.51 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
A50.51 is the ICD-10-CM diagnosis code for clutton's joints. Clutton's joints is a painless swelling of the knees and other large joints that occurs in children with congenital syphilis. This condition results from inflammation caused by syphilis infection passed from mother to child before birth. A50.51 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering infections with a predominantly sexual mode of transmission (a50-a64).
A50.51 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Clutton's joints is a manifestation of late congenital syphilis and should be coded with A50.51 specifically; verify documentation confirms this is congenital syphilis rather than acquired syphilis.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for A50.51 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Clutton's joints is a manifestation of late congenital syphilis and should be coded with A50.51 specifically; verify documentation confirms this is congenital syphilis rather than acquired syphilis
- •This code is typically used in pediatric cases; ensure the patient age and clinical presentation align with congenital syphilis diagnosis, and consider coding the underlying congenital syphilis condition as well