Post-traumatic osteoarthritis of the left hip occurring unilaterally, where documented prior trauma — fracture, dislocation, or significant soft-tissue injury — is the established cause of joint degeneration.

Documentation tips

What should appear in the chart to support M16.52.

Source · Editorial brief grounded in 6 cited references ↓

• Explicitly name the prior traumatic event (e.g., 'left acetabular fracture 2018') and link it causally to the current OA diagnosis — 'post-traumatic' must appear in or be clearly implied by the note.
• Specify laterality as 'left hip' by name; do not rely on side-of-body indicators alone to support the 6th-character selection.
• Record radiographic findings that confirm OA: joint space narrowing, osteophytes, subchondral sclerosis, or cystic changes on AP pelvis or dedicated left hip views.
• Document functional limitations and conservative treatment history (PT, NSAIDs, injections) when building a surgical authorization record — payers often require this before approving arthroplasty.
• If the contralateral hip carries a different OA etiology, document both hips independently so each can be coded with the appropriate specificity.

Related CPT procedures

Procedure codes commonly billed with M16.52. 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 M16.52 and adjacent codes.

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

• Defaulting to M16.12 (primary OA, left hip) when the note mentions a prior injury but the physician has not explicitly attributed the OA to that trauma — confirm the causal link before upgrading to M16.52.
• Using M16.52 when both hips are post-traumatically arthritic; bilateral post-traumatic hip OA requires M16.4, not two unilateral codes.
• Dropping to the unspecified code M16.50 when laterality is clearly documented — M16.52 is the billable, most-specific code and should always be used when the left hip is named.
• Confusing M16.52 with M16.7 (other unilateral secondary OA, hip) — post-traumatic OA has its own dedicated subcategory (M16.5x) and should not be defaulted to the 'other secondary' bucket.
• Omitting the prior-trauma etiology from the problem list entirely, leaving only a generic 'hip pain' code that won't support medical necessity for advanced imaging or surgical intervention.

Clinical context

Source · Editorial summary grounded in 6 cited references ↓

Sibling codes

Other billable codes under M16.5 (laterality / anatomic variants).