Bilateral osteoarthritis of both hips caused by underlying developmental hip dysplasia, where abnormal socket coverage accelerates cartilage breakdown and leads to secondary degenerative joint disease.

Documentation tips

What should appear in the chart to support M16.2.

Source · Editorial brief grounded in 5 cited references ↓

• Explicitly state that the hip OA is caused by or resulting from dysplasia — 'bilateral hip OA secondary to developmental hip dysplasia' is the language that justifies M16.2 over M16.0.
• Include radiographic findings that confirm both the dysplastic anatomy (e.g., shallow acetabulum, lateral center-edge angle, Tönnis angle) and the arthritic changes (joint space narrowing, osteophytes, subchondral sclerosis).
• Document the history of hip dysplasia with onset or prior diagnosis date; if previously treated (e.g., pediatric casting, osteotomy), note that history to establish the structural etiology.
• Record functional impact bilaterally — pain with weight-bearing, reduced walking tolerance, ROM deficits in both hips — to support medical necessity for imaging and procedural authorization.
• If imaging was performed, reference the specific study (e.g., AP pelvis X-ray, CT arthrogram) and quantify findings (Kellgren-Lawrence grade, degree of joint space narrowing) for both sides.

Related CPT procedures

Procedure codes commonly billed with M16.2. 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 M16.2 and adjacent codes.

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

• Assigning M16.0 (bilateral primary OA of hip) when the note documents hip dysplasia as the cause — M16.0 is idiopathic; dysplasia-driven OA belongs in M16.2.
• Using M16.2 when only one hip has dysplastic OA — unilateral dysplastic OA requires M16.31 (right) or M16.32 (left), not M16.2.
• Dropping to M16.9 (osteoarthritis of hip, unspecified) because the coder couldn't confirm dysplasia from the note — query the provider rather than downcode; specificity is auditable.
• Coding bilateral hip dysplasia without documented OA under M16.2 — dysplasia alone does not satisfy this code; the arthritic sequela must be confirmed and documented.
• Failing to capture the underlying dysplasia diagnosis as an additional code when relevant for a more complete clinical picture, particularly in surgical cases where payers may want the full etiology chain.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

Sibling codes

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