ICD-10-CM · General

M71.80

M71.80 classifies a bursopathy that is neither bursitis nor a standard bursal cyst but falls under a specified type of bursal pathology — used only when the affected site is not documented or cannot be determined.

Verified May 8, 2026 · 3 sources ↓

Status
Billable
Chapter
13
Related CPT
5
Region
General
Drawn from CDCICD10DataAAPC

Documentation tips

What should appear in the chart to support M71.80.

Source · Editorial brief grounded in 3 cited references ↓

  • Record the anatomic site of the bursa by name (e.g., subacromial, prepatellar, trochanteric) — any documented site forces a more specific M71.8x code and avoids the unspecified default.
  • Specify the type of bursopathy in the assessment: inflammation, fibrosis, bursal hypertrophy, or villonodular change, so reviewers understand why M71.8x was chosen over standard bursitis (M71.1x).
  • If ultrasound or MRI was performed, document the bursal structure identified on imaging and its location; radiology findings that name a site upgrade coding specificity.
  • Note the clinical history distinguishing this from infectious bursitis (M71.0x) or bursal cyst (M71.3x), since those categories carry different code families and payer rules.
  • When the bursopathy affects a prosthetic joint area, confirm whether a complication code (T84 series) better describes the condition before defaulting to M71.80.

Related CPT procedures

Procedure codes commonly billed with M71.80. 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 M71.80 and adjacent codes.

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

  • Using M71.80 when the site is actually documented — any named joint or anatomic region in the note requires M71.81 through M71.89 instead; the unspecified-site code is not a shortcut.
  • Confusing M71.80 ('other specified bursopathy, unspecified site') with M71.9 ('bursopathy, unspecified') — M71.80 requires a clinician to have identified a specific type of bursopathy; M71.9 is used when the type itself is unknown.
  • Assigning M71.80 for standard bursitis — routine inflammatory bursitis belongs in M71.1x (other infective bursitis) or M70.x (soft tissue disorders related to use/pressure), not M71.80.
  • Failing to check payer LCD/NCD requirements before submitting M71.80 with injection or aspiration CPT codes — unspecified-site diagnoses often trigger automatic medical necessity review or denial.

Clinical context

Source · Editorial summary grounded in 3 cited references ↓

M71.80 sits at the bottom of the M71.8x subcategory, which covers bursopathies that are 'other specified' — meaning the clinician has identified a distinct bursal condition (not simple bursitis, not a basic bursal cyst) but has not documented or cannot assign a named anatomic site. The '0' as the final character signals unspecified site, making this a last-resort code when site documentation is genuinely absent.

In orthopedic practice, this code surfaces when encounter notes describe atypical bursal inflammation, fibrosis, or bursal hyperplasia without tying the finding to a specific joint or region. Before assigning M71.80, exhaust site-specific options: M71.81–M71.89 cover shoulder, elbow, wrist, hand, hip, knee, ankle/foot, and other specified sites respectively. If imaging or clinical notes identify a location — even broadly (e.g., 'periarticular knee region') — a site-specific code is required.

M71.80 is billable and valid for FY2026 claims, but payers frequently scrutinize unspecified-site codes for medical necessity. Pair it with procedure codes for bursal aspiration, injection, or imaging only when the operative or progress note genuinely lacks anatomic specificity. If the encounter documents a site after the fact, amend the code.

Sibling codes

Other billable codes under M71.8 (laterality / anatomic variants).

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 3 cited references ↓

01When is M71.80 the correct code versus M71.9?
Use M71.80 when the clinician has identified a specific type of bursopathy (e.g., bursal fibrosis, villonodular bursitis) but has not documented the anatomic site. Use M71.9 when neither the type nor the site is specified — M71.9 is the true 'unknown everything' code.
02Does M71.80 require a 7th character extension?
No. M71.80 is a Chapter 13 M-code (musculoskeletal); 7th-character extensions (A/D/S) apply to injury S-codes, not to M-codes. Submit the six-character code as written.
03Can M71.80 support medical necessity for a bursal injection or aspiration?
It can, but unspecified-site codes draw payer scrutiny. If the procedure note identifies the joint being injected, code to the site-specific M71.8x equivalent instead; M71.80 on an injection claim without further documentation is a common audit trigger.
04What distinguishes M71.80 from the M70.x bursitis codes?
M70.x codes (e.g., M70.50 trochanteric bursitis) cover bursitis related to use, overuse, or pressure and all carry laterality. M71.80 is reserved for pathologically distinct bursal conditions (not standard overuse bursitis) where site is undocumented. If the condition is overuse bursitis at a known site, M70.x is correct.
05Is M71.80 valid for FY2026 claims?
Yes. M71.80 is a billable, valid code in the FY2026 ICD-10-CM code set (effective October 1, 2025), per the CDC ICD-10-CM Tabular List 2026.
06What site-specific alternatives should be checked before coding M71.80?
Review M71.81 (shoulder), M71.82 (elbow), M71.83 (wrist), M71.84 (hand), M71.85 (hip), M71.86 (knee), M71.87 (ankle and foot), and M71.88 (other site). If any named location appears in the note, one of these codes replaces M71.80.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

  1. 01CDC ICD-10-CM Tabular List 2026 (effective Oct 1, 2025)
  2. 02
    icd10data.com
    https://www.icd10data.com/ICD10CM/Codes/M00-M99/M70-M79/M71-/M71.80
  3. 03
    aapc.com
    https://www.aapc.com/codes/icd-10-codes/M71

Mira AI Scribe

Mira AI Scribe captures the bursal structure identified on exam or imaging (name, region, laterality), the character of the pathology (inflammatory, fibrotic, hypertrophic), and any prior treatment attempts. That documentation determines whether M71.80 or a site-specific M71.8x subcategory applies — preventing an unspecified-site code from triggering a medical necessity denial on bursal aspiration or injection claims.

See how Mira captures M71.80 documentation

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