M76.70

M76.70 identifies peroneal tendinitis when the treating provider has not specified whether the affected leg is right or left. It covers chronic, overuse-driven inflammation of the peroneal tendons without a documented laterality.

Verified May 8, 2026 · 4 sources ↓

Status: Billable
Chapter: 13
Related CPT: 10
Region: Foot & ankle

Drawn from CDCICD10DataIcdcodesAAPC

Documentation tips

What should appear in the chart to support M76.70.

Source · Editorial brief grounded in 4 cited references ↓

Name the affected side explicitly in the assessment — 'right' or 'left' — so M76.71 or M76.72 can be used instead of the unspecified M76.70.
Record physical exam findings over the lateral ankle: tenderness posterior to the lateral malleolus, pain with resisted eversion, and any peroneal groove pathology.
Document imaging results that support chronic tendinitis: MRI or ultrasound findings such as tendon thickening, intratendinous signal change, or peritendinous edema.
Note the chronicity and mechanism — overuse, repetitive ankle inversion, or sport activity — to distinguish this from an acute traumatic tear (S86.39-).
Include prior conservative treatment attempted (PT, bracing, NSAIDs) to establish medical necessity when billing for further intervention.

Related CPT procedures

Procedure codes commonly billed with M76.70. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

27605 $337.02

Percutaneous tenotomy of the Achilles tendon performed under local anesthesia, in which tendon fibers are divided through small punctures to release contracture or correct deformity.

27606 $254.85

Percutaneous tenotomy of the Achilles tendon performed through a needle or small stab incision without open exposure of the tendon.

28300 $611.24

Osteotomy of the calcaneus (heel bone) to correct foot alignment, with or without internal fixation — encompasses Dwyer, Chambers, and sliding-type procedures.

29515 $82.50

Application of a short leg splint extending from the calf down to the foot for immobilization of the lower leg, ankle, or foot.

73721 $204.41

MRI of a lower extremity joint (hip, knee, or ankle) performed without contrast material.

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.

20550 $60.46

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

76881 View procedure details

76882 View procedure details

97530 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M76.70 and adjacent codes.

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

Defaulting to M76.70 when laterality is actually documented in the note — always check the HPI, physical exam, and imaging report before accepting 'unspecified.'
Using M76.70 for an acute peroneal tendon tear; traumatic tears require S86.39- with the appropriate 7th character (A, D, or S), not an enthesopathy M-code.
Confusing peroneal tendinitis with posterior tibial tendinitis (M76.82x); peroneal pathology is lateral, posterior tibial is medial — laterality on exam should guide the correct code family.
Omitting a laterality-specific code on payer claims that flag 'unspecified' codes for medical necessity review or downcode reimbursement.

Clinical context

Source · Editorial summary grounded in 4 cited references ↓

M76.70 is the fallback code in the M76.7 peroneal tendinitis family when chart documentation fails to name the side. The laterality-specific codes — M76.71 (right) and M76.72 (left) — are always preferred. Use M76.70 only when the note genuinely lacks laterality, not as a shortcut.

Peroneal tendinitis is classified under M76 (Enthesopathies, lower limb, excluding foot) within Chapter 13. It maps to MS-DRG 557 (Tendonitis, myositis and bursitis with MCC) or 558 (without MCC) under MS-DRG v43.0. The condition reflects chronic, degenerative inflammation of the peroneal tendons — typically the peroneus longus and brevis — posterior to the lateral malleolus. It is distinct from acute traumatic peroneal tendon tears, which belong under S86.39- (injury codes requiring 7th-character encounter designation).

If you're coding for an acute peroneal tendon tear rather than chronic tendinitis, do not use M76.70. Chronic tendinosis with documented imaging findings (tendon thickening, peritendinous edema on MRI or ultrasound) supports the M76.7x family. Conservative care history — physical therapy, bracing, activity modification — strengthens medical necessity for continued treatment under this code.

Sibling codes

Other billable codes under M76.7 (laterality / anatomic variants).

M76.72

Peroneal tendinitis, left leg

M76.71

Peroneal tendinitis, right leg

Frequently asked questions

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

01When should I use M76.70 versus M76.71 or M76.72?

Use M76.70 only when the documentation genuinely omits laterality. If the provider documents 'right' or 'left' anywhere in the encounter note, use M76.71 (right) or M76.72 (left). Unspecified codes invite payer scrutiny and should be the exception, not the default.

02Can I use M76.70 for an acute peroneal tendon tear?

No. Acute traumatic peroneal tendon tears code to S86.39- with a 7th-character encounter designation (A = initial, D = subsequent, S = sequela). M76.70 is reserved for chronic, inflammatory tendinitis — not structural tendon disruption from a discrete injury.

03What imaging documentation best supports M76.70?

MRI findings of tendon thickening, intratendinous signal change, or peritendinous edema are the strongest support. Ultrasound showing hypoechoic tendon changes or fluid in the tendon sheath also validates the diagnosis. Document the specific findings in the assessment, not just 'imaging obtained.'

04What MS-DRG does M76.70 map to?

M76.70 maps to MS-DRG 557 (Tendonitis, myositis and bursitis with MCC) or 558 (without MCC) under MS-DRG v43.0, per the CDC ICD-10-CM Tabular List 2026.

05Is peroneal tendinitis excluded from the M76 enthesopathies when it involves the foot?

The M76 category covers enthesopathies of the lower limb excluding foot. Peroneal tendinitis at the ankle level (posterior to the lateral malleolus) codes here. Enthesopathies of the ankle and foot proper are directed to M77.5-. If clinical documentation localizes pathology to the foot insertion, review M77.5- before finalizing M76.70.

06What CPT codes are commonly billed alongside M76.70?

Common pairings include diagnostic ultrasound (76881, 76882), MRI of the ankle (73721), ultrasound-guided injection (20550), physical therapy codes (97110, 97530), and cast/splint application (29515). Surgical CPTs such as 27605 (tenotomy) or 27606 may apply when conservative care fails.

Sources & references

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

01CDC ICD-10-CM Tabular List 2026 (effective Oct 1, 2025)
02
icd10data.com
https://www.icd10data.com/ICD10CM/Codes/M00-M99/M70-M79/M76-/M76.70
03
icdcodes.ai
https://icdcodes.ai/diagnosis/peroneal-tendonitis/documentation
04
aapc.com
https://www.aapc.com/codes/icd-10-codes/M76.70

Mira AI Scribe

Mira AI Scribe captures the affected side by name, the location of tenderness (posterior to the lateral malleolus), resisted eversion pain, and MRI or ultrasound findings at the time of dictation — preventing a drop to M76.70 unspecified when M76.71 or M76.72 is clearly supported by the chart.

See how Mira captures M76.70 documentation