ICD-10 Code for Left Knee Pain: For Coders and Clinicians

Left knee pain is one of the most frequent complaints seen in clinics, physical therapy centers, and orthopedic practices. For medical coders, choosing the correct left knee pain ICD-10 code is essential because it directly affects reimbursement, claim approval, and patient records. Even a minor documentation gap can result in denied claims or inaccurate clinical histories.

This article explores the exact code for left knee pain, explains its variations, and highlights why accurate documentation matters in daily medical practice. You will also find real-life scenarios, practical tips, and a quick checklist to make coding more reliable.

The Standard ICD-10 Code for Left Knee Pain

The official ICD-10 code for left knee pain is M25.562.

This code is part of the M25 series, which addresses pain in joints, with the final digit specifying location and side.

Clinical Importance of Documenting Left Knee Pain

Accurate documentation is not just a billing requirement. It is the bridge between a patient’s symptoms and the care they receive. Let’s consider a real-world scenario.

A 52-year-old woman visits her physician complaining of pain in her left knee that worsens when climbing stairs. The doctor documents “knee pain” without specifying laterality. The claim submitted uses the unspecified code M25.569. Insurance rejects it, requesting clarification. This delay pushes back her physical therapy start date, prolonging her discomfort.

Now imagine the same case, but this time the physician writes “left knee pain, aggravated by climbing stairs, chronic for six months.” The coder assigns M25.562 along with a supporting note about chronicity. The claim is approved without issue, the patient gets timely therapy, and the clinical record supports ongoing management.

This example shows why left vs. right specification, acute vs. chronic nature, and context of pain are essential. Coding accuracy impacts:

• Timely insurance approval

• Correct treatment pathways

• Research and population health data accuracy

• Reduced back-and-forth between providers and payers

Breakdown of Related Codes

While M25.562 is the base code, documentation sometimes requires additional specificity:

Acute vs. Chronic Left Knee Pain

Differentiating between acute and chronic pain improves coding accuracy.

• Acute Pain: Sudden, often linked to injury, inflammation, or recent surgery. Example: A teenager with a sports injury coded as M25.562 + G89.11.

• Chronic Pain: Lasting more than three months, often from arthritis or degenerative conditions. Example: A 65-year-old with osteoarthritis coded as M25.562 + G89.29.

Adding these secondary codes provides payers with a clearer clinical picture and avoids underreporting.

Coding Scenarios: Mini Case Studies

1. Sports Injury Case

   • A 19-year-old soccer player experiences acute swelling and pain in the left knee after a collision.

   • Documentation: “Acute traumatic left knee pain.”

   • Code: M25.562 + G89.11.

2. Arthritis Case

   • A 70-year-old patient reports long-term stiffness and pain, especially in the mornings.

   • Documentation: “Chronic osteoarthritis-related left knee pain.”

   • Code: M25.562 + G89.29 + M17.12 (Unilateral primary osteoarthritis, left knee).

3. Post-Surgical Case

   • A middle-aged man reports pain three weeks after left knee replacement surgery.

   • Documentation: “Post-surgical left knee pain.”

   • Code: M25.562 + G89.18.

These examples illustrate how supporting documentation drives coding accuracy and improves claim acceptance.

Common Mistakes in Coding Left Knee Pain

• Using M25.569 when the side is documented

• Forgetting to add a chronic or acute pain code

• Confusing joint pain with soft tissue pain codes

• Failing to link secondary conditions such as arthritis

Correcting these mistakes can drastically reduce claim denials.

Checklist for Coding Left Knee Pain

• Always confirm laterality (left vs. right vs. unspecified)

• Note duration (acute or chronic)

• Record cause (injury, arthritis, surgery, or unknown)

• Add secondary codes if relevant

• Avoid unspecified codes unless documentation is incomplete

FAQs

What is the ICD-10 code for left knee pain?
The standard code is M25.562, which specifically describes pain in the left knee joint.

Do I need to code both M25.562 and a chronic pain code?
Yes, if the pain is long-term, pair M25.562 with G89.29 to clarify chronicity.

Can acute and chronic codes be used together?
Not at the same time. Use acute codes like G89.11 only for sudden pain episodes and chronic codes like G89.29 for long-standing pain.

What if the provider only documents “knee pain”?
In that case, coders must use M25.569 (unspecified knee pain), though it risks claim denial. Always query for clarification.

Is arthritis-related knee pain coded differently?
Yes. Pair M25.562 with an arthritis code such as M17.12 when documentation supports it.

Conclusion

The left knee pain ICD-10 code (M25.562) may look simple, but accuracy depends on detailed documentation. Coders should always consider whether the pain is acute, chronic, or linked to another condition. Adding specific secondary codes not only prevents claim denials but also ensures patients receive timely care.

By applying precise documentation and coding practices, healthcare providers can protect revenue cycles, support patient outcomes, and maintain data accuracy.