M77.8

Enthesopathy at a peripheral site that does not map to any more specific code in the M77 category — covering elbow, wrist, carpus, forearm, hand, upper arm, pelvis, and multi-site presentations not classified elsewhere.

Verified May 8, 2026 · 4 sources ↓

Status: Billable
Chapter: 13
Related CPT: 10
Region: Multi-region

Drawn from CDCICD10DataAAPCUnboundmedicine

Documentation tips

What should appear in the chart to support M77.8.

Source · Editorial brief grounded in 4 cited references ↓

Name the exact anatomical site (e.g., 'right wrist extensor insertion,' 'bilateral elbow enthesopathy') — this confirms M77.8 is appropriate rather than the unspecified M77.9.
Document that the pathology is at the tendon or ligament insertion point, not within the bursa, to defend against downcoding to M71.9x or a bursitis code.
Record imaging findings that support enthesopathy — ultrasound showing tendon insertion thickening, calcification, or Doppler hyperemia; or MRI/X-ray showing bony reaction at the enthesis.
Include onset, duration, and aggravating factors (repetitive use, occupation, sport) to establish medical necessity for conservative and procedural interventions.
If multiple sites are involved, list each site explicitly so that M77.8's 'multiple sites' index entry is supported and a payer cannot argue unspecified coding.

Related CPT procedures

Procedure codes commonly billed with M77.8. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

20550 $60.46

Injection into a single tendon sheath, ligament, or aponeurosis (such as the plantar fascia) — one anatomical site per unit.

20551 $60.46

Injection of a therapeutic substance into the origin or insertion point of a single tendon, used to treat tendinitis, enthesopathy, or localized inflammation at the bone-tendon junction.

73070 $29.39

Radiographic examination of the elbow joint using a minimum of 2 views to evaluate bone structure and surrounding tissues.

73080 $33.07

Radiologic examination of the elbow, complete, requiring a minimum of three views.

73100 $34.40

Radiologic examination of the wrist with a minimum of two views.

73110 $42.75

Radiologic examination of the wrist, complete, requiring a minimum of three views

97110 $29.06

Therapeutic exercise billed per 15-minute unit, targeting strength, endurance, range of motion, or flexibility with direct one-on-one patient contact.

76881 View procedure details

76882 View procedure details

97530 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M77.8 and adjacent codes.

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

Defaulting to M77.9 (enthesopathy unspecified) when the site is actually documented — if the note says 'wrist enthesopathy' or 'elbow tendinopathy at insertion,' M77.8 is the correct pick, not M77.9.
Using M77.8 for lateral or medial epicondylitis, which have their own specific codes (M77.11/M77.12 and M77.01/M77.02 respectively) — M77.8 is not correct for those named diagnoses.
Coding M77.8 when the pathology is actually a bursitis: Excludes1 under M77 prohibits using any M77 code with bursitis NOS (M71.9x).
Assigning M77.8 for spinal enthesopathy (e.g., Achilles insertion at calcaneus is peripheral and may fit, but thoracic or lumbar enthesopathy routes to M46.0x — verify the anatomical region before coding).
Confusing M77.8 with M77.5x (other enthesopathy of foot and ankle) — foot and ankle enthesopathies that don't meet plantar fasciitis criteria should go to M77.50–M77.52, not M77.8.

Clinical context

Source · Editorial summary grounded in 4 cited references ↓

M77.8 is the catch-all billable code for peripheral enthesopathies that fall outside the named conditions in M77 (lateral epicondylitis M77.1x, medial epicondylitis M77.0x, plantar fasciitis M77.3x, metatarsalgia M77.4, other foot/ankle enthesopathy M77.5x). Use it when the documented site is the elbow region (non-specific), wrist, carpus, forearm, hand, upper arm, pelvis, or when multiple sites are involved simultaneously and no single dominant site drives coding.

Before assigning M77.8, confirm the pathology involves a tendon or ligament insertion — not a bursa. Bursitis NOS maps to M71.9x (Excludes1 under M77). Osteophyte without enthesopathy context maps to M25.7. Spinal enthesopathy routes to M46.0x. If the enthesopathy is truly unspecified with no anatomical detail, M77.9 is appropriate — but M77.8 is correct when the site is documented and simply doesn't match a more specific code.

M77.8 groups into MS-DRG 557 (Tendonitis, myositis and bursitis with MCC) and MS-DRG 558 (without MCC) under v43.0. The code carries no laterality substructure; if the payer or clinical program requires side documentation, note it in the record even though the code itself does not distinguish right from left.

Sibling codes

Other billable codes under M77 (laterality / anatomic variants).

M77.9

Enthesopathy, unspecified

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 4 cited references ↓

01When should I use M77.8 instead of M77.9?

Use M77.8 when the anatomical site is documented but doesn't correspond to a named M77 subcategory (e.g., wrist, elbow region generically, forearm, hand, pelvis, or multiple sites). Reserve M77.9 only when no anatomical detail is available.

02Can M77.8 be used for lateral epicondylitis of the elbow?

No. Lateral epicondylitis has its own codes: M77.11 (right) and M77.12 (left). M77.8 covers other elbow-region enthesopathies that are not epicondylitis and not medial epicondylitis (M77.0x).

03Does M77.8 have laterality substructure?

No. Unlike other M77 codes, M77.8 has no right/left/bilateral subcodes. Document the affected side clearly in the clinical note even though the code itself does not capture it.

04Is M77.8 appropriate for Achilles tendon insertion enthesopathy?

It depends on site classification. The Achilles insertion at the calcaneus is a foot/ankle structure; consider M77.50–M77.52 first. M77.8 covers enthesopathies of the elbow, wrist, forearm, hand, upper arm, pelvis, and multi-site presentations — confirm site before assigning.

05What CPT procedures are commonly linked to M77.8?

Tendon sheath or ligament injection (20550, 20551), musculoskeletal ultrasound of the elbow (73070, 73080) or wrist (73100, 73110), and ultrasound guidance for injections (76881, 76882) are typical pairings depending on the treated site.

06Can M77.8 be coded alongside a bursitis code?

No. M77 carries an Excludes1 note for bursitis NOS (M71.9x), meaning these codes cannot be reported together. If the documented condition is bursitis, use M71.9x rather than any M77 code.

07What MS-DRG does M77.8 map to for inpatient billing?

M77.8 groups to MS-DRG 557 (Tendonitis, myositis and bursitis with MCC) or MS-DRG 558 (without MCC) under MS-DRG v43.0.

Sources & references

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

Mira Scribe

Mira AI Scribe captures the insertion-site location (elbow, wrist, carpus, forearm, hand, upper arm, pelvis, or multiple sites), laterality, duration of symptoms, aggravating activities, physical exam findings at the enthesis (tenderness on palpation, swelling, crepitus), and imaging results (ultrasound or MRI findings at the tendon attachment). This prevents fallback to the less specific M77.9 and provides the audit trail needed to justify procedural billing for injection or ultrasound guidance.

See how Mira captures M77.8 documentation