ICD-10-CM · Elbow

M77.00

Medial epicondylitis of the elbow when laterality (right or left) is not documented in the clinical record — the unspecified-side fallback under parent code M77.0.

Verified May 8, 2026 · 7 sources ↓

Status: Billable
Chapter: 13
Related CPT: 14
Region: Elbow

Drawn from CDCICD10DataAAPCIcdcodesOutsourcestrategies

Documentation tips

What should appear in the chart to support M77.00.

Source · Editorial brief grounded in 7 cited references ↓

Specify laterality by name — 'right' or 'left' — in the assessment or diagnosis line; a single word upgrades M77.00 to M77.01 or M77.02 and eliminates the unspecified flag.
Record the physical exam findings that clinically validate the diagnosis: point tenderness over the medial epicondyle, positive resisted wrist flexion test (e.g., Golfer's Elbow Test), and any ulnar nerve involvement.
If ultrasound or MRI was performed, summarize the relevant finding (tendon hypoechogenicity, partial-thickness tear, signal change at the common flexor origin) rather than just noting 'imaging obtained.'
Document activity or occupational history that establishes the overuse mechanism (repetitive forearm pronation, grip-heavy work, throwing sports) to support medical necessity for conservative and interventional treatment.
If conservative care has been trialed, record the modalities and duration (e.g., 6 weeks of PT, NSAIDs, bracing) — many payer LCDs for injection or surgical procedures require documented failed conservative care.

Related CPT procedures

Procedure codes commonly billed with M77.00. 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.

24357 $384.44

Percutaneous repair of the elbow tendon, performed through a minimally invasive approach without a large open incision.

24358 $500.01

Open tenotomy of the lateral or medial elbow with debridement of soft tissue and/or bone, performed for conditions such as lateral epicondylitis (tennis elbow) or medial epicondylitis (golfer's elbow).

24359 $616.91

Open elbow tenotomy with soft tissue and/or bone debridement plus tendon repair or reattachment, performed at the lateral or medial epicondyle for conditions such as epicondylitis.

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.

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.

99213 $95.19

Established patient office or outpatient visit requiring 20–29 minutes of total time or low-complexity medical decision-making.

99214 $135.61

Office visit for an established patient requiring moderate-complexity medical decision making (MDM), or 30–39 minutes of total provider time on the date of service.

99203 $117.57

New patient office or outpatient visit requiring a medically appropriate history and/or examination with low-complexity medical decision-making, or 30–44 minutes of total provider time on the date of the encounter.

99204 $177.36

New patient office or outpatient visit requiring moderate medical decision making, or 45–59 minutes of total provider time on the date of the encounter.

76942 View procedure details

97112 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M77.00 and adjacent codes.

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

Defaulting to M77.00 when the chart clearly documents one side — if the provider wrote 'right elbow' anywhere in the note, use M77.01; unspecified coding on a lateralized claim invites medical necessity denials and audit scrutiny.
Confusing medial epicondylitis (M77.0x) with lateral epicondylitis (M77.1x) — 'golfer's elbow' is medial; 'tennis elbow' is lateral. Swapping the codes is a common error when copying forward from a prior encounter.
Coding M77.00 alongside bursitis NOS (M71.9–) violates the Excludes1 rule at the M77 category level — those conditions cannot be coded together.
Omitting a secondary code for cubital tunnel syndrome (G56.2x) when the provider documents concurrent ulnar nerve involvement, which is clinically common and affects the procedure and payer pathway.

Clinical context

Source · Editorial summary grounded in 7 cited references ↓

M77.00 applies when a provider diagnoses golfer's elbow (medial epicondylitis) but the clinical documentation does not specify which side is affected. It sits beneath parent code M77.0 (Medial epicondylitis) alongside M77.01 (right elbow) and M77.02 (left elbow). Because ICD-10-CM demands the highest level of specificity supported by documentation, M77.00 should be a last resort — use it only when the note genuinely omits laterality, not as a convenience code when you haven't checked.

Medial epicondylitis is an enthesopathy of the common flexor-pronator tendon origin at the medial humeral epicondyle, typically driven by repetitive wrist flexion and forearm pronation. Clinically, it presents with point tenderness over the medial epicondyle, pain with resisted wrist flexion, and sometimes with ulnar nerve symptoms at the cubital tunnel. Imaging findings supporting the diagnosis include ultrasound-demonstrated tendon hypoechogenicity or MRI signal change at the common flexor origin.

M77.00 groups into MS-DRG 557 (Tendonitis, myositis and bursitis with MCC) or 558 (without MCC) under MS-DRG v43.0. The category M77 carries an Excludes1 for bursitis NOS (M71.9–) and Excludes2 notes for bursitis due to use/overuse/pressure (M70.–), osteophyte (M25.7), and spinal enthesopathy (M46.0–). No 7th-character extension is required for this M-code.

Sibling codes

Other billable codes under M77.0 (laterality / anatomic variants).

M77.02

Medial epicondylitis, left elbow

M77.01

Medial epicondylitis, right elbow

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 7 cited references ↓

01When is it acceptable to use M77.00 instead of M77.01 or M77.02?

Only when the clinical documentation genuinely does not specify which elbow is affected — for example, an initial telehealth triage note with no physical exam. If laterality appears anywhere in the note, use the specific code.

02What is the difference between M77.00, M77.01, and M77.02?

All three code medial epicondylitis under parent M77.0. The 6th character distinguishes laterality: 0 = unspecified elbow, 1 = right elbow, 2 = left elbow. Use the most specific code the documentation supports.

03Can M77.00 be billed with a corticosteroid injection CPT code such as 20550 or 20551?

Yes, but some payers cross-reference the injection site against the diagnosis code for laterality consistency. If the injection is clearly performed on one side, the lateralized code (M77.01 or M77.02) reduces the risk of a medical necessity denial.

04Is a 7th character required for M77.00?

No. M77.00 is a complete, billable code with no 7th-character extension. The A/D/S encounter-type extensions apply to injury S-codes, not to M-category enthesopathy codes.

05What CPT codes are commonly linked to an M77.00 diagnosis in an orthopedic setting?

Common pairings include 20550/20551 (injection into tendon sheath or origin), 24357–24359 (surgical epicondylitis procedures), 73070/73080 (elbow X-ray), 76942 (ultrasound guidance for injection), and evaluation and management codes 99203–99215 depending on visit complexity.

06Does M77.00 exclude concurrent coding of cubital tunnel syndrome?

No exclusion applies. If the provider documents concurrent ulnar nerve entrapment at the elbow, code G56.2x (with appropriate laterality) as an additional diagnosis — it is a clinically distinct condition and affects treatment planning.

07What MS-DRGs does M77.00 map to for inpatient encounters?

M77.00 groups to MS-DRG 557 (Tendonitis, myositis and bursitis with MCC) or MS-DRG 558 (without MCC) under MS-DRG v43.0, per the ICD-10-CM 2026 tabular grouper data.

Sources & references

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

Mira AI Scribe

The Mira AI Scribe captures the affected side, tenderness location (medial epicondyle), provocative test results (resisted wrist flexion), any imaging summary, and prior conservative care history directly from the encounter note. This ensures automatic selection of M77.01 or M77.02 over the unspecified M77.00, preventing specificity downcoding, payer flags for unspecified laterality, and missing documentation that blocks injection or surgical authorization.

See how Mira captures M77.00 documentation