ICD-10 Codes for Knee Pain — M25.561, M25.562 and M17 Osteoarthritis Guide

M25.561 vs M25.562 vs M25.569 — the pain code family

Knee pain without a confirmed underlying cause is coded from the M25.56 family, split entirely by laterality:

• M25.561 — Pain in right knee
• M25.562 — Pain in left knee
• M25.569 — Pain in unspecified knee

Laterality is not optional when the chart documents it. If the note names the affected knee anywhere, the claim should carry M25.561 or M25.562 — not M25.569. Defaulting to the unspecified code when the documentation states a side is a specificity denial the coder chose, not one the documentation caused.

When knee pain isn't the diagnosis

This is the distinction that trips up the most claims: M25.56x is a symptom code, not a disease code. It exists to describe knee pain when no underlying diagnosis — osteoarthritis, a meniscus tear, tendinitis, a ligament sprain — has been confirmed yet.

The moment a provider confirms a specific cause, that diagnosis becomes the code, and the symptom code is generally dropped rather than kept as a companion. Coding both a confirmed diagnosis and the pain symptom on the same claim is a redundancy error most payer edit logic will catch.

M17 — the complete knee osteoarthritis code family

Once osteoarthritis is confirmed — usually by imaging — coding moves to the M17 family, which is organized by laterality and by type (primary, post-traumatic, or secondary):

• M17.0 — Bilateral primary osteoarthritis of knee
• M17.10 / M17.11 / M17.12 — Unilateral primary osteoarthritis, unspecified / right / left knee
• M17.2 — Bilateral post-traumatic osteoarthritis of knee
• M17.30 / M17.31 / M17.32 — Unilateral post-traumatic osteoarthritis, unspecified / right / left knee
• M17.4 — Other bilateral secondary osteoarthritis of knee
• M17.5 — Other unilateral secondary osteoarthritis of knee
• M17.9 — Osteoarthritis of knee, unspecified

"Primary" means degenerative wear-and-tear with no other identified cause — typically age-related. "Post-traumatic" requires the chart to document the original injury. "Secondary" covers osteoarthritis caused by something else entirely, such as a prior infection or another systemic condition — the underlying cause should be sequenced first when it's separately documented.

Bilateral knee pain — there's no combined code

There is no single ICD-10-CM code for "bilateral knee pain." When both knees are affected and no diagnosis has been confirmed, report M25.561 and M25.562 together — one code per knee. This follows Official Guidelines Section I.B.2 (Level of Detail in Coding), which directs coders to the highest level of detail the documentation supports.

The same logic extends to confirmed osteoarthritis: if both knees show osteoarthritis, M17.0 (bilateral primary) or M17.2 (bilateral post-traumatic) applies as a single code — bilateral osteoarthritis does have a combined code, unlike bilateral pain.

Other confirmed diagnoses that replace the pain code

Osteoarthritis isn't the only diagnosis that supersedes the M25.56x pain code. Other common examples:

• S83.2- — Meniscus tear, current injury (with laterality and specific meniscus)
• M23.3- — Other meniscus derangements (older or degenerative tears)
• M22.2X1 / M22.2X2 — Patellofemoral disorders, right / left knee
• M76.5- — Patellar tendinitis, with laterality
• S83.5- — Knee ligament sprain, current injury

In each case, once the provider's note confirms the specific condition, that code takes over from the pain code — not alongside it, unless the documentation explicitly states the pain is unrelated to the confirmed diagnosis.

Complete knee pain and osteoarthritis reference table

Common coding mistakes

Mistake 1 — Defaulting to M25.569 when the chart states laterality

If the note names the affected knee anywhere, the unspecified code is not appropriate. This is one of the most common and most preventable specificity denials in musculoskeletal coding.

Mistake 2 — Keeping M25.56x on the claim after osteoarthritis is confirmed

Once imaging or the assessment confirms osteoarthritis, the M17 code replaces the pain code. Carrying both is a redundancy error that payer edit logic routinely catches.

Mistake 3 — Confusing a symptom code with a disease code

M25.561 (pain) and M17.11 (osteoarthritis) describe fundamentally different things — a symptom versus a confirmed disease. Treating them as interchangeable, or using the pain code as a "safer" default once a diagnosis exists, misrepresents the clinical picture.

Mistake 4 — Coding bilateral pain with a single code

There is no combined bilateral knee pain code. Bilateral knee pain requires M25.561 and M25.562 reported together — one code per knee.

Mistake 5 — Using M17.9 on surgical claims when more specificity is available

M17.9 (unspecified osteoarthritis of knee) is a frequent trigger for prepayment review on total knee arthroplasty claims. If the operative note or imaging supports laterality and type, use the specific M17 code instead.

Look up related codes