• June 12, 2024

Find the Right ICD 10 Code for Left Knee Pain (2025 Update)

ICD 10 code for left knee pain - One Month free Medical Billing Service offered by PROMBS

The International Classification of Diseases, 10th Revision (ICD-10) provides a universal system for documenting diagnoses, enabling standardized communication among healthcare providers, insurers, and regulatory agencies.

Among the many frequently coded conditions, left knee pain is one of the most common musculoskeletal issues seen in outpatient settings. Whether it's due to injury, overuse, or degenerative conditions, correctly identifying the ICD-10 code for left knee pain is crucial for accurate documentation, effective treatment, and proper reimbursement.

What Is the ICD-10 Code for Left Knee Pain?

M25.562 – Pain in left knee

This code applies when the pain is localized to the left knee and no more specific diagnosis (like a tear or osteoarthritis) has been established. It's a symptom-based code, used primarily during the initial evaluation or when pain exists without a known underlying condition.

Why Is the ICD-10 Code Important?

Correct ICD-10 coding ensures:
  • Accurate diagnosis recording
  • Smooth insurance claims processing
  • Improved clinical communication
  • Proper billing and reimbursement
Using M25.562 not only communicates the patient's condition, but also protects your practice from potential denials and compliance issues.

Left Knee Pain Terminologies and Their ICD-10 Descriptions

Let’s break down how different scenarios of left knee pain are coded in ICD-10. Each variation helps capture the full clinical picture.
Condition / Scenario ICD-10 Code Code Description
General Left Knee Pain M25.562 Pain in the left knee
Left Knee Joint Pain (no confirmed diagnosis) M25.562 Same as above – symptom-based code used when no underlying cause is known
Osteoarthritis of the Left Knee M17.12 Unilateral primary osteoarthritis, left knee
Left Knee Pain with Swelling M25.562 + M25.362 Pain + Swelling of left knee (use both if both are clinically significant)
Left Knee Pain After a Fall M25.562 + W19.XXXA Pain + External cause (unspecified fall) — use correct extension for situation
Injury to Left Knee (unspecified) S80.912A Unspecified superficial injury of left knee, initial encounter
Left Knee Sprain (ligament-related) S83.92XA Sprain of unspecified site of left knee, initial encounter
Left Knee Strain (muscle/tendon-related) S86.812A Strain of other muscle(s) and tendon(s) at the lower leg level, left leg, initial
Left Knee Pain with Effusion M25.562 + M25.462 Pain + Effusion (fluid buildup) in the left knee
Unspecified Left Knee Pain M25.562 The default code when no further details are available

1. ICD-10 Pain in Left Knee – M25.562

This is the default and most frequently used code for general, nonspecific pain in the left knee. Use it when the source of pain hasn’t been diagnosed but is documented as present.

2. Left Knee Joint Pain ICD-10 – M25.562

This is the same code as above, but emphasizes that the pain is located within the joint, not in surrounding soft tissues. Still, unless a specific pathology (e.g., arthritis, tear) is identified, M25.562 is appropriate.

3. Left Knee Osteoarthritis ICD-10 – M17.12

If the pain is due to degenerative changes, such as osteoarthritis, use a more specific code:

M17.12 – Unilateral primary osteoarthritis, left knee
This provides greater specificity for both clinical and billing purposes.
Want to learn more about arthritis-related codes? See our ICD-10 Codes for Osteoarthritis guide.

4. L Knee Pain ICD-10 – M25.562

“L Knee” is often used in EHRs or SOAP notes as a shorthand for left knee pain. The ICD-10 code remains M25.562, but always ensure clarity in documentation to support the code.

5. Left Knee Injury ICD-10 – S80.912A

For injuries where the exact nature is unspecified (e.g., "knee injury from fall"), use:

S80.912A – Unspecified superficial injury of left knee, initial encounter
Remember: For injury codes (S-codes), the 7th character ‘A’ is for the initial encounter. Use ‘D’ for subsequent and ‘S’ for sequela.
Always pair with an external cause code if the injury was from trauma (e.g., fall, accident).

6. Left Knee Sprain ICD-10 – S83.92XA

Sprains affecting ligaments in the left knee are coded as:

S83.92XA – Sprain of unspecified site of left knee, initial encounter
This is appropriate when ligament damage is suspected or confirmed but not specified.

7. Left Knee Strain ICD-10 – S86.812A

Muscle or tendon strains in the left knee area should be reported as:

S86.812A – Strain of other muscle(s) and tendon(s) at lower leg level, left leg, initial encounter
Be sure documentation includes details on whether it’s a muscle or tendon strain.

Specific Scenarios & How to Code Them

1. Left Knee Pain and Swelling

When pain is accompanied by visible or palpable swelling, you may need more than one code:
  • M25.562 for the pain
  • M25.362 for swelling of the left knee
Use both only if both symptoms are independently documented and clinically significant

2. Left Knee Pain After a Fall

If pain follows a fall, you’ll typically need:

  • M25.562 for the pain
  • W19.XXXA for “unspecified fall, initial encounter”
    Use W19.XXXA – Unspecified fall, initial encounter (replace ‘XXX’ with appropriate extension if needed based on cause or location of fall).

This coding supports both the symptom and the mechanism of injury, improving billing accuracy.

3. Left Knee Pain Unspecified

When no further detail is available regarding cause, severity, or location beyond “left knee pain,” M25.562 remains the default and appropriate code.

4. Left Knee Pain with Effusion

Effusion (fluid buildup) in the joint indicates a more specific issue. In this case:

  • M25.562 for pain
  • M25.462 – Effusion, left knee

This dual coding approach ensures the full scope of the condition is documented.

5. Left Knee Pain Due to Osteoarthritis

When osteoarthritis is confirmed, always code the condition, not just the symptom:
Use M17.12 rather than M25.562
This provides diagnostic clarity and prevents downcoding.

2025 ICD-10 Coding Tips for Knee Pain

As of the 2025 ICD-10 updates, no major changes were made to these codes, but here are some best practices to follow:

  • Always confirm laterality (left, right, or bilateral)
  • Use initial encounter (A), subsequent (D), or sequela (S) as needed for injuries
  • Match symptoms to causes when possible to avoid overusing symptom codes like M25.562
  • If imaging or specialist evaluation confirms a cause (e.g., meniscus tear, arthritis), code that condition directly

Why Accurate Coding Matters

Proper ICD-10 coding improves not only clinical documentation but also ensures:

  • Faster insurance approval
  • Fewer claim rejections or audits
  • Improved care coordination across providers
  • Data tracking for outcomes and population health


Incorrect use of symptom codes (like M25.562) without identifying the root cause can lead to denials or downcoding, especially in follow-up visits or for chronic pain cases.

Whether you're a solo practitioner or part of a larger medical group, using the right codes protects both patient care and practice revenue.

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Conclusion

The ICD-10 code for left knee pain (M25.562) remains unchanged in 2025. However, understanding how and when to use it, especially in combination with related symptom or injury codes, is more important than ever. Accurate documentation and coding are essential for clean claims, faster reimbursements, and better patient care.