Unspecified lordosis localized to the lumbosacral region, representing an abnormal anterior curvature at the L5-S1 junction without a documented specific etiology or subtype.

Documentation tips

What should appear in the chart to support M40.57.

Source · Editorial brief grounded in 4 cited references ↓

• Specify the region by name — 'lumbosacral' or 'L5-S1 junction' — in the assessment to justify M40.57 over M40.56 (lumbar) or M40.50 (site unspecified).
• Record imaging findings that confirm the curvature: Cobb angle measurement, degree of lumbar lordosis on standing lateral X-ray, and the vertebral levels involved.
• If an underlying condition (e.g., spondylolisthesis, obesity, hip flexor contracture) contributes to the lordosis, document it explicitly and sequence it first per 'Code First' instructions at M40.
• Document whether the lordosis is postural or structural, and whether it is symptomatic — this determines whether a more specific M40 subcategory applies and whether a symptom code should be added.
• Note any conservative treatment history (physical therapy, bracing, orthotics) to support medical necessity for ongoing evaluation and management.

Related CPT procedures

Procedure codes commonly billed with M40.57. 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 M40.57 and adjacent codes.

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

• Confusing M40.56 (lumbar region) with M40.57 (lumbosacral region) — if the curve apex or clinical documentation centers on L5-S1 or the sacral base angle, use M40.57; if it centers on L1-L5, use M40.56.
• Assigning M40.57 when the lordosis is congenital — congenital kyphosis and lordosis is coded to Q76.4, which is an Excludes1 condition under M40 and cannot coexist with M40.57.
• Failing to sequence the underlying disease first when lordosis is a manifestation — the 'Code First' note at M40 requires the primary condition (e.g., ankylosing spondylitis, neuromuscular disease) to appear before M40.57 on the claim.
• Using M40.57 when postprocedural lordosis is documented — postprocedural kyphosis and lordosis belongs under M96.- and is Excludes1 at M40.
• Defaulting to M40.57 when M40.47 (other lordosis, lumbosacral region) is more accurate — if the provider characterizes the lordosis type but it doesn't fit postural or secondary categories cleanly, review M40.4x before settling on the unspecified subcategory.

Clinical context

Source · Editorial summary grounded in 4 cited references ↓

Sibling codes

Other billable codes under M40.5 (laterality / anatomic variants).