ICD-10-CM · Elbow

M77.10

Lateral epicondylitis (tennis elbow) affecting an elbow where the treating provider has not documented or specified whether it is the right or left side.

Verified May 8, 2026 · 8 sources ↓

Status: Billable
Chapter: 13
Related CPT: 10
Region: Elbow

Drawn from CDCICD10DataAAPCCMSNIH

Documentation tips

What should appear in the chart to support M77.10.

Source · Editorial brief grounded in 8 cited references ↓

Always document laterality by name — 'right elbow' or 'left elbow' — so you can bill the specific code M77.11 or M77.12 instead of M77.10.
Record provocative test findings (Cozen's test, Mill's test, chair-pick-up test) and the affected anatomical structure (lateral epicondyle of humerus / extensor carpi radialis brevis origin) to establish clinical specificity.
Note any imaging performed (X-ray to rule out bony pathology, ultrasound or MRI showing tendinopathy or partial tear at the common extensor origin) to support medical necessity.
Document conservative care history — duration of symptoms, prior physical therapy, NSAIDs, bracing — before coding for injection or surgical procedures, as payers often require it.
If billing for a corticosteroid or PRP injection, specify the medication name, dose, and exact injection site; CMS pain-management coding guidance ties HCPCS drug code requirements to the laterality-specific M77.11/M77.12 codes, not M77.10.

Related CPT procedures

Procedure codes commonly billed with M77.10. 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.

20610 $68.81

Aspiration and/or injection of a major joint or bursa (shoulder, hip, knee, or subacromial bursa) performed without ultrasound guidance.

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.

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.

97530 $35.07

Dynamic, functional activities that use multiple parameters such as balance, strength, and range of motion together to improve real-world performance, billed in 15-minute units.

29837 $506.69

Arthroscopic surgical procedure on the elbow involving limited debridement of damaged tissue within the joint.

73070 $29.39

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

Common coding pitfalls

The recurring mistakes coders make with M77.10 and adjacent codes.

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

Defaulting to M77.10 when the provider note says 'tennis elbow' without a side — query the provider; lateral epicondylitis is almost always unilateral and the affected side is clinically obvious.
Billing M77.10 for a payer whose LCD or billing-and-coding article lists only M77.11 and M77.12 as covered diagnoses — this will result in a medical necessity denial.
Confusing lateral epicondylitis (M77.1x) with medial epicondylitis/golfer's elbow (M77.0x) — the lateral epicondyle is on the outer aspect of the elbow; verify anatomical side before selecting the category.
Using the non-billable parent code M77.1 on a claim — M77.1 is not a valid billing code; you must carry the code to the 5th character (M77.10, M77.11, or M77.12).
Omitting laterality modifiers (RT/LT) on procedure codes when M77.10 is used — if you cannot upgrade to a specific code, at minimum append the appropriate side modifier to the CPT to reduce denial risk.

Clinical context

Source · Editorial summary grounded in 8 cited references ↓

M77.10 is the fallback code within the M77.1 lateral epicondylitis family — use it only when the clinical documentation genuinely fails to identify which elbow is affected. The ICD-10-CM tabular structure makes laterality explicit: M77.11 = right elbow, M77.12 = left elbow, M77.10 = unspecified. Because unspecified codes draw payer scrutiny and can trigger medical necessity denials, M77.10 should appear on a claim only as a last resort when the note is truly ambiguous and cannot be queried.

Lateral epicondylitis is classified under M77 (Other enthesopathies), with the Applicable To note at M77.1 confirming that 'tennis elbow' maps here. The condition reflects enthesopathy at the origin of the extensor muscles on the lateral humeral epicondyle — not intra-articular pathology. Several CMS billing and coding articles (outpatient OT, home health OT, pain management injections) explicitly list M77.11 and M77.12 as the laterality-specific codes that support medical necessity; M77.10 does not appear in those approved code groups. That omission is a practical signal: payers who require a laterality-specific code will deny a claim submitted with M77.10.

Common comorbid or concurrent codes include M25.521/M25.522 (pain in right/left elbow), M79.621/M79.622 (pain in right/left upper arm), and G56.01/G56.02 (carpal tunnel syndrome, which can coexist). Do not confuse with M77.00–M77.02 (medial epicondylitis/golfer's elbow) or with M70-series bursitis codes, which are excluded from the M77 category.

Sibling codes

Other billable codes under M77.1 (laterality / anatomic variants).

M77.11

Lateral epicondylitis, right elbow

M77.12

Lateral epicondylitis, left elbow

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 8 cited references ↓

01When is it ever appropriate to bill M77.10 instead of M77.11 or M77.12?

Only when the clinical note genuinely does not specify which elbow is affected and the provider cannot be queried before the claim must be submitted. In practice this is rare — lateral epicondylitis is almost always documented or observable on one specific side. Exhaust all query options before defaulting to M77.10.

02Does M77.10 appear on CMS billing-and-coding articles as a covered diagnosis for injections or therapy?

No. CMS billing-and-coding articles for outpatient OT (A53064), home health OT (A53057), and pain-management injections (DA52863) list M77.11 and M77.12 but not M77.10. Submitting M77.10 for those services risks a medical necessity denial.

03Is 'tennis elbow' always coded to M77.1x?

Yes. The ICD-10-CM Applicable To note at M77.1 maps 'tennis elbow' directly to the lateral epicondylitis codes. Select the appropriate 5th character: M77.11 (right), M77.12 (left), or M77.10 (unspecified).

04Can M77.10 be billed with an elbow pain code like M25.529 on the same claim?

Elbow pain (M25.52x) is typically redundant when lateral epicondylitis is the established diagnosis, since pain is inherent to the condition. Add a pain code only if the pain is a separate, distinct complaint not fully captured by the epicondylitis code — which is unusual.

05What CPT codes are most commonly paired with M77.10 or its laterality-specific siblings?

Injection of a single tendon origin/insertion (20551) and injection of a major joint or bursa (20610) are the most common procedural pairings. For surgical management, 24357 (epicondyle debridement without implant), 24358, and 24359 apply. Physical and occupational therapy codes 97110 and 97530 are used for conservative rehabilitation.

06How does M77.10 differ from its parent code M77.1?

M77.1 is a non-billable category header — it cannot be placed on a claim. M77.10 is the billable 5th-character extension representing the unspecified-laterality variant. You must use M77.10, M77.11, or M77.12 on any reimbursement claim; M77.1 alone will be rejected.

07Should I use a laterality modifier (RT/LT) when billing with M77.10?

If you cannot upgrade to M77.11 or M77.12, appending modifier RT (right side) or LT (left side) to the procedure code is a best-practice safeguard. It does not substitute for the specific ICD-10 code, but it provides payers additional laterality context and may reduce denial rates.

Sources & references

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

Mira Scribe

Mira AI Scribe captures the affected elbow side, provocative test results (Cozen's, Mill's), palpation findings at the lateral epicondyle, symptom duration, and any imaging or prior treatment from the encounter note — automatically populating M77.11 or M77.12 instead of the unspecified M77.10. This prevents medical necessity denials on payer LCDs that require laterality-specific codes and eliminates post-submission queries back to the provider.

See how Mira captures M77.10 documentation