Unilateral hip osteoarthritis that developed secondary to a cause other than trauma or dysplasia — such as metabolic disease, inflammatory arthritis, or avascular necrosis — affecting one hip only.

Documentation tips

What should appear in the chart to support M16.7.

Source · Editorial brief grounded in 6 cited references ↓

• Document the affected side explicitly (right or left hip) in the assessment — M16.7 has no laterality subcharacter, so the chart must carry that detail for audit defense and future specificity.
• Name the underlying secondary cause (e.g., senile osteoporosis, gout, avascular necrosis, prior inflammatory arthritis) so a secondary diagnosis code can be added — this supports medical necessity and DRG MCC/CC capture.
• Record imaging findings that confirm degenerative change: joint space narrowing, osteophyte formation, subchondral sclerosis, or cyst formation on X-ray or MRI.
• Distinguish secondary from primary OA in the assessment note — 'secondary osteoarthritis of the right hip due to age-related osteoporosis' is audit-proof; 'hip OA' is not.
• If the contralateral hip is unaffected, document that explicitly to justify unilateral coding and avoid queries about whether M16.6 (bilateral secondary) should apply.

Related CPT procedures

Procedure codes commonly billed with M16.7. 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 M16.7 and adjacent codes.

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

• Defaulting to M16.9 (osteoarthritis of hip, unspecified) when the record clearly documents a secondary etiology — M16.7 is always more specific and should be used instead.
• Confusing M16.7 with M16.5x (unilateral post-traumatic osteoarthritis): if the OA is attributable to a prior fracture, dislocation, or other hip injury, post-traumatic codes take precedence over M16.7.
• Using M16.7 when dysplastic OA is documented — developmental dysplasia as the underlying cause maps to M16.31 (right) or M16.32 (left), not M16.7.
• Forgetting to add the code for the secondary cause (e.g., M81.0 for osteoporosis) — M16.7 captures the arthritic manifestation but does not encode the precipitating condition.
• Applying M16.7 to bilateral secondary OA — bilateral cases require M16.6, not M16.7.

Clinical context

Source · Editorial summary grounded in 6 cited references ↓

Inclusion & exclusion notes

Per the official ICD-10-CM Tabular List.

Source · CDC ICD-10-CM Official Tabular List · 2026

Sibling codes

Other billable codes under M16 (laterality / anatomic variants).