Patellar tendinitis of the left knee — an enthesopathy involving inflammation of the patellar tendon at or near its origin on the inferior pole of the left patella.

Documentation tips

What should appear in the chart to support M76.52.

Source · Editorial brief grounded in 6 cited references ↓

• Provider must explicitly name the affected side ('left knee') — 'bilateral' alone does not justify M76.52 without a separate left-specific statement.
• Document the specific anatomical finding: tenderness at the inferior patellar pole, not generic anterior knee pain.
• Record load-dependent symptom pattern (pain with jumping, squatting, or stair descent) to clinically validate tendinitis over patellofemoral syndrome.
• If MRI was obtained, include findings such as tendon signal abnormality, thickening, or partial tearing to support medical necessity for advanced imaging and interventional procedures.
• Note chronicity and any conservative care attempted (physical therapy, activity modification, bracing) — payers may require this before approving injections or surgical referral.

Related CPT procedures

Procedure codes commonly billed with M76.52. 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 M76.52 and adjacent codes.

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

• Defaulting to M76.50 (unspecified knee) when the laterality is documented in the note but missed during abstraction — always read the physical exam section.
• Confusing patellar tendinitis (M76.52) with patellofemoral pain syndrome (M22.2x1 for left) — these are clinically and structurally distinct; the provider's diagnosis governs.
• Coding M76.52 alone for bilateral disease — if both knees are affected and documented, you must also assign M76.51 for the right side.
• Applying a 7th-character extension to M76.52 — M-codes do not use 7th-character encounter extensions (A/D/S); those apply to injury S-codes only.
• Using M76.52 when the documented condition is Achilles tendinitis of the left leg (M76.62) — verify anatomical site before code selection.

Clinical context

Source · Editorial summary grounded in 6 cited references ↓

Sibling codes

Other billable codes under M76.5 (laterality / anatomic variants).