The Ultimate Guide to Knee Pain ICD-10 for Physical Therapists

Knee pain is one of the most frequent musculoskeletal conditions physical therapists address. From acute sports injuries to chronic osteoarthritis, effective treatment begins with precise documentation - and that includes choosing the right ICD-10 code.

But navigating ICD-10 knee pain codes isn’t always straightforward. Therapists and practice owners must ensure accurate laterality, avoid common mistakes, and streamline their documentation to keep billing on track and compliant.

This guide explains everything physical therapy professionals need to know about the knee pain ICD-10 family of codes, including how to document, when to use specific codes, and how to make the process painless.

What Is the ICD-10 Code for Knee Pain?

Knee pain is categorized under the musculoskeletal section of the ICD-10 system. Specifically, it falls under subcategory M25.56 — Pain in joint, knee. This category includes three main codes based on the location (laterality) of the pain:

🔹 ICD-10 Knee Pain Codes Table

These are the most commonly used codes for knee pain in physical therapy. Avoid M25.569 unless there is no way to determine which knee is affected.

When to Use Each Code

1. Right Knee Pain ICD-10

• Code: M25.561
  
  
• Use when: The patient reports pain localized in the right knee.
  
  
• Related keyword: ICD 10 code for right knee pain
  
  

2. Left Knee Pain ICD-10

• Code: M25.562
  
  
• Use when: The pain is documented as being in the left knee.
  
  
• Related keyword: ICD 10 code for left knee pain
  
  

3. Bilateral Knee Pain ICD-10

• Code: Use both M25.561 and M25.562
  
  
• Use when: The patient presents with pain in both knees. There is no single bilateral code in the ICD-10 system.
  
  
• Related keyword: bilateral knee pain ICD 10
  
  

4. Unspecified Knee Pain ICD-10

• Code: M25.569
  
  
• Use when: The affected side is not documented or not known. This code should be a last resort.
  
  
• Related keyword: ICD 10 code knee pain
  
  

Why Accurate Coding Matters

Accurate coding is more than just a formality—it directly impacts your clinic’s bottom line and compliance status.

⚠️ What Can Go Wrong with Inaccurate Coding?

• Claim Denials: Payers may reject or delay reimbursement if you use unspecified codes unnecessarily.
  
  
• Compliance Risk: Improper coding can trigger audits and result in penalties.
  
  
• Data Gaps: Accurate records are essential for treatment tracking and clinical outcomes.
  
  

Documentation Tips for Physical Therapists

✅ Best Practices

• Specify laterality clearly (e.g., "left knee pain when descending stairs")
  
  
• For bilateral cases, describe each knee’s symptoms separately.

• Avoid assumptions—always verify the affected side with the patient.
  
  
• Do not overuse M25.569—use it only when absolutely necessary.
  
  

Common Mistakes to Avoid

• ❌ Using unspecified codes as default
  
  
• ❌ Failing to document laterality
  
  
• ❌ Ignoring annual ICD-10 updates
  
  
• ❌ Assuming bilateral = one code (you must code both knees)
  
  

ICD-10 Knee Pain Code Quick Reference Table

How to Streamline Knee Pain ICD-10 Coding

🧩 Tools and Processes to Implement

• Use structured templates with left/right checkboxes
  
  
• Integrate EMR alerts for incomplete codes
  
  
• Train your team annually on ICD-10 coding updates
  
  
• Pre-load common scenarios into your documentation software (e.g., post-op ACL rehab, osteoarthritis cases)
  
  

Beyond Pain: Related Knee ICD-10 Codes for PTs

Knee pain might be a starting point, but many physical therapy evaluations lead to more specific diagnoses that warrant different ICD-10 codes. Knowing when to move beyond M25.56 can enhance your clinical accuracy.

🦵 Common Related Diagnoses

Knowing when to escalate your code from general joint pain to a more detailed diagnosis can strengthen documentation and justify ongoing care.

Tips for ICD-10 Success Across the Care Team

Ensuring everyone in your practice understands and follows ICD-10 best practices makes a significant impact.

👥 Team Strategies

• Front desk staff should verify referral documentation includes laterality.
  
  
• Therapists should confirm and note specifics clearly in every visit.
  
  
• Billing teams should review documentation before claim submission.
  
  
• Owners/managers should track denial rates and update training.
  
  

Clear workflows and shared accountability make your entire clinic more efficient and reduce costly mistakes.

Why PtEverywhere Is the Smart Choice for ICD-10 Coding

With PtEverywhere, physical therapy professionals spend less time coding and more time treating patients. The system ensures that your ICD-10 usage is compliant, fast, and fully integrated with your billing operations.

Conclusion

Mastering the correct use of knee pain ICD-10 codes—especially laterality—is essential for every physical therapist and practice owner. With codes like M25.561 (right knee) and M25.562 (left knee) being standard in musculoskeletal care, precision matters. And in bilateral cases, always remember: two knees = two codes.

Whether you're billing for left knee pain ICD 10, right knee pain ICD 10, or managing a complex rehab case, clarity in documentation and efficiency in coding go hand-in-hand.

Let PtEverywhere help you make it easier. Accurate. Streamlined. Compliant.

Want to simplify ICD-10 coding in your clinic? Start with the right software. Start with PtEverywhere.