M35.7 classifies hypermobility syndrome — a connective tissue condition characterized by excessive joint laxity beyond normal range, often associated with chronic pain, recurrent subluxations, and generalized ligamentous laxity including familial ligamentous laxity.

Documentation tips

What should appear in the chart to support M35.7.

Source · Editorial brief grounded in 5 cited references ↓

• Record a Beighton score (0–9) with specific positive findings (e.g., thumb-to-forearm, elbow/knee hyperextension) to support the hypermobility diagnosis and distinguish it from EDS criteria.
• Explicitly state whether systemic features of Ehlers-Danlos syndrome are absent — this protects the M35.7 selection and satisfies the Type 1 Excludes rule.
• Document recurrent joint events by site and frequency (e.g., 'patellar subluxations x3 in past year, bilateral') to justify associated joint-specific codes billed alongside M35.7.
• If using M35.7 as a proxy for hypermobility spectrum disorder (HSD), note that in the record — HSD has no dedicated ICD-10-CM code, and M35.7 is the accepted clinical workaround.
• Capture functional impact and conservative care history (PT, bracing, prior imaging) to support medical necessity for orthopedic evaluation and therapeutic services.

Related CPT procedures

Procedure codes commonly billed with M35.7. 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 M35.7 and adjacent codes.

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

• Billing M35.7 and Q79.62 (hypermobile EDS) on the same claim violates the Type 1 Excludes rule — these codes can never be used together; choose one based on whether formal EDS criteria are met.
• Using M35.7 for a localized hypermobile joint (e.g., a single hypermobile thumb) is a miscoding — M35.7 reflects a systemic or generalized syndrome, not isolated joint laxity.
• Assuming M35.7 covers all connective tissue hypermobility without provider documentation of the syndrome; the diagnosis must be explicitly documented — 'loose joints' alone is insufficient.
• Omitting secondary joint-specific codes (e.g., M25.5x for arthralgia, M25.3x for instability) when the orthopedic visit is driven by a specific joint complaint — M35.7 alone may not capture the full clinical picture.
• Confusing the MS-DRG assignment: M35.7 maps to DRG 557/558 (Tendonitis, Myositis and Bursitis), which may surprise coders expecting a connective tissue DRG — verify payer grouper logic before submission.

Clinical context

Source · Editorial summary grounded in 5 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 M35 (laterality / anatomic variants).