M72.1 captures fibroblastic thickening of the skin overlying the dorsal interphalangeal or metacarpophalangeal joints — the fibrous plaques clinically known as knuckle pads or Garrod's pads.

Documentation tips

What should appear in the chart to support M72.1.

Source · Editorial brief grounded in 8 cited references ↓

• Identify the affected joint(s) by name — specify which finger(s) and whether the MCP or PIP joint is involved.
• Distinguish dorsal fibrous plaques (knuckle pads → M72.1) from palmar nodules or cords (Dupuytren's → M72.0); conflating the two is the single most common coding error in this code family.
• Document whether knuckle pads coexist with Dupuytren's contracture — if both are present and independently diagnosed, both M72.1 and M72.0 can be reported.
• Note functional impact (grip limitation, skin breakdown, pain) to support medical necessity for physical therapy or procedural intervention.
• Record prior conservative care attempted (splinting, corticosteroid injection, PT) when submitting for surgical or procedural authorization.

Related CPT procedures

Procedure codes commonly billed with M72.1. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

Common coding pitfalls

The recurring mistakes coders make with M72.1 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

• Coding M72.0 (Dupuytren's) when the documented finding is dorsal knuckle pad thickening — the two fibromatoses are anatomically and clinically distinct and explicitly separated in the Tabular List.
• Assuming M72.1 requires a laterality digit — it does not; the code is complete at five characters for right, left, or bilateral presentation.
• Reporting M72.9 (fibroblastic disorder, unspecified) when the provider clearly documents knuckle pads — M72.1 is the specific billable code and should be used when documentation supports it.
• Omitting a finger-level modifier on associated procedure codes when payer policy requires digit-specific identification — the diagnosis M72.1 carries no built-in laterality, so procedural specificity must come from CPT modifiers (e.g., F1–F9).

Clinical context

Source · Editorial summary grounded in 8 cited references ↓

Sibling codes

Other billable codes under M72 (laterality / anatomic variants).