Resources · ICD-10 · Knee
Knee ICD-10 codes an orthopedic practice actually uses
Billable FY2026 codes for the knee from the official ICD-10-CM release, organized the way calls come in — arthritis, soft tissue, and injuries — with the laterality and 7th-character rules that keep claims clean.
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Knee diagnosis codes, from the official FY2026 files
From the pre-arthroplasty M17 osteoarthritis family to the S83 sprain-and-tear codes that follow every pivot injury, these are the billable FY2026 ICD-10-CM codes for knee diagnoses. Meniscus codes (M23) branch by which meniscus, which zone, and which side; injury codes need their 7th character.
Every code below is billable in FY2026. Descriptions are reproduced verbatim from the official ICD-10-CM release (NCHS/CMS — public domain). 147 codes shown on this page.
Osteoarthritis of the knee (M17)
| Code | Official FY2026 description |
|---|---|
| M17.0 | Bilateral primary osteoarthritis of knee |
| M17.10 | Unilateral primary osteoarthritis, unspecified knee |
| M17.11 | Unilateral primary osteoarthritis, right knee |
| M17.12 | Unilateral primary osteoarthritis, left knee |
| M17.2 | Bilateral post-traumatic osteoarthritis of knee |
| M17.30 | Unilateral post-traumatic osteoarthritis, unspecified knee |
| M17.31 | Unilateral post-traumatic osteoarthritis, right knee |
| M17.32 | Unilateral post-traumatic osteoarthritis, left knee |
| M17.4 | Other bilateral secondary osteoarthritis of knee |
| M17.5 | Other unilateral secondary osteoarthritis of knee |
| M17.9 | Osteoarthritis of knee, unspecified |
Patellar disorders (M22)
| Code | Official FY2026 description |
|---|---|
| M22.00 | Recurrent dislocation of patella, unspecified knee |
| M22.01 | Recurrent dislocation of patella, right knee |
| M22.02 | Recurrent dislocation of patella, left knee |
| M22.10 | Recurrent subluxation of patella, unspecified knee |
| M22.11 | Recurrent subluxation of patella, right knee |
| M22.12 | Recurrent subluxation of patella, left knee |
| M22.2X1 | Patellofemoral disorders, right knee |
| M22.2X2 | Patellofemoral disorders, left knee |
| M22.2X9 | Patellofemoral disorders, unspecified knee |
| M22.3X1 | Other derangements of patella, right knee |
| M22.3X2 | Other derangements of patella, left knee |
| M22.3X9 | Other derangements of patella, unspecified knee |
| M22.40 | Chondromalacia patellae, unspecified knee |
| M22.41 | Chondromalacia patellae, right knee |
| M22.42 | Chondromalacia patellae, left knee |
| M22.8X1 | Other disorders of patella, right knee |
| M22.8X2 | Other disorders of patella, left knee |
| M22.8X9 | Other disorders of patella, unspecified knee |
| M22.90 | Unspecified disorder of patella, unspecified knee |
| M22.91 | Unspecified disorder of patella, right knee |
| M22.92 | Unspecified disorder of patella, left knee |
Meniscus and internal derangement (M23)
| Code | Official FY2026 description |
|---|---|
| M23.000 | Cystic meniscus, unspecified lateral meniscus, right knee |
| M23.001 | Cystic meniscus, unspecified lateral meniscus, left knee |
| M23.002 | Cystic meniscus, unspecified lateral meniscus, unspecified knee |
| M23.003 | Cystic meniscus, unspecified medial meniscus, right knee |
| M23.004 | Cystic meniscus, unspecified medial meniscus, left knee |
| M23.005 | Cystic meniscus, unspecified medial meniscus, unspecified knee |
| M23.006 | Cystic meniscus, unspecified meniscus, right knee |
| M23.007 | Cystic meniscus, unspecified meniscus, left knee |
| M23.009 | Cystic meniscus, unspecified meniscus, unspecified knee |
| M23.011 | Cystic meniscus, anterior horn of medial meniscus, right knee |
| M23.012 | Cystic meniscus, anterior horn of medial meniscus, left knee |
| M23.019 | Cystic meniscus, anterior horn of medial meniscus, unspecified knee |
| M23.021 | Cystic meniscus, posterior horn of medial meniscus, right knee |
| M23.022 | Cystic meniscus, posterior horn of medial meniscus, left knee |
| M23.029 | Cystic meniscus, posterior horn of medial meniscus, unspecified knee |
| M23.031 | Cystic meniscus, other medial meniscus, right knee |
| M23.032 | Cystic meniscus, other medial meniscus, left knee |
| M23.039 | Cystic meniscus, other medial meniscus, unspecified knee |
| M23.041 | Cystic meniscus, anterior horn of lateral meniscus, right knee |
| M23.042 | Cystic meniscus, anterior horn of lateral meniscus, left knee |
| M23.049 | Cystic meniscus, anterior horn of lateral meniscus, unspecified knee |
| M23.051 | Cystic meniscus, posterior horn of lateral meniscus, right knee |
| M23.052 | Cystic meniscus, posterior horn of lateral meniscus, left knee |
| M23.059 | Cystic meniscus, posterior horn of lateral meniscus, unspecified knee |
| M23.061 | Cystic meniscus, other lateral meniscus, right knee |
| M23.062 | Cystic meniscus, other lateral meniscus, left knee |
| M23.069 | Cystic meniscus, other lateral meniscus, unspecified knee |
| M23.200 | Derangement of unspecified lateral meniscus due to old tear or injury, right knee |
| M23.201 | Derangement of unspecified lateral meniscus due to old tear or injury, left knee |
| M23.202 | Derangement of unspecified lateral meniscus due to old tear or injury, unspecified knee |
| M23.203 | Derangement of unspecified medial meniscus due to old tear or injury, right knee |
| M23.204 | Derangement of unspecified medial meniscus due to old tear or injury, left knee |
| M23.205 | Derangement of unspecified medial meniscus due to old tear or injury, unspecified knee |
| M23.206 | Derangement of unspecified meniscus due to old tear or injury, right knee |
| M23.207 | Derangement of unspecified meniscus due to old tear or injury, left knee |
| M23.209 | Derangement of unspecified meniscus due to old tear or injury, unspecified knee |
| M23.211 | Derangement of anterior horn of medial meniscus due to old tear or injury, right knee |
| M23.212 | Derangement of anterior horn of medial meniscus due to old tear or injury, left knee |
| M23.219 | Derangement of anterior horn of medial meniscus due to old tear or injury, unspecified knee |
| M23.221 | Derangement of posterior horn of medial meniscus due to old tear or injury, right knee |
+71 more billable codes in this family — see the official CMS ICD-10-CM files for the complete set.
Knee pain and effusion (M25.46-, M25.56-)
| Code | Official FY2026 description |
|---|---|
| M25.461 | Effusion, right knee |
| M25.462 | Effusion, left knee |
| M25.469 | Effusion, unspecified knee |
| M25.561 | Pain in right knee |
| M25.562 | Pain in left knee |
| M25.569 | Pain in unspecified knee |
Tendinitis and bursitis (M76.5-, M70.4-, M70.5-)
| Code | Official FY2026 description |
|---|---|
| M70.40 | Prepatellar bursitis, unspecified knee |
| M70.41 | Prepatellar bursitis, right knee |
| M70.42 | Prepatellar bursitis, left knee |
| M70.50 | Other bursitis of knee, unspecified knee |
| M70.51 | Other bursitis of knee, right knee |
| M70.52 | Other bursitis of knee, left knee |
| M76.50 | Patellar tendinitis, unspecified knee |
| M76.51 | Patellar tendinitis, right knee |
| M76.52 | Patellar tendinitis, left knee |
Sprains, ligament tears and dislocations — initial encounter (S83)
| Code | Official FY2026 description |
|---|---|
| S83.001A | Unspecified subluxation of right patella, initial encounter |
| S83.002A | Unspecified subluxation of left patella, initial encounter |
| S83.003A | Unspecified subluxation of unspecified patella, initial encounter |
| S83.004A | Unspecified dislocation of right patella, initial encounter |
| S83.005A | Unspecified dislocation of left patella, initial encounter |
| S83.006A | Unspecified dislocation of unspecified patella, initial encounter |
| S83.011A | Lateral subluxation of right patella, initial encounter |
| S83.012A | Lateral subluxation of left patella, initial encounter |
| S83.013A | Lateral subluxation of unspecified patella, initial encounter |
| S83.014A | Lateral dislocation of right patella, initial encounter |
| S83.015A | Lateral dislocation of left patella, initial encounter |
| S83.016A | Lateral dislocation of unspecified patella, initial encounter |
| S83.091A | Other subluxation of right patella, initial encounter |
| S83.092A | Other subluxation of left patella, initial encounter |
| S83.093A | Other subluxation of unspecified patella, initial encounter |
| S83.094A | Other dislocation of right patella, initial encounter |
| S83.095A | Other dislocation of left patella, initial encounter |
| S83.096A | Other dislocation of unspecified patella, initial encounter |
| S83.101A | Unspecified subluxation of right knee, initial encounter |
| S83.102A | Unspecified subluxation of left knee, initial encounter |
| S83.103A | Unspecified subluxation of unspecified knee, initial encounter |
| S83.104A | Unspecified dislocation of right knee, initial encounter |
| S83.105A | Unspecified dislocation of left knee, initial encounter |
| S83.106A | Unspecified dislocation of unspecified knee, initial encounter |
| S83.111A | Anterior subluxation of proximal end of tibia, right knee, initial encounter |
| S83.112A | Anterior subluxation of proximal end of tibia, left knee, initial encounter |
| S83.113A | Anterior subluxation of proximal end of tibia, unspecified knee, initial encounter |
| S83.114A | Anterior dislocation of proximal end of tibia, right knee, initial encounter |
| S83.115A | Anterior dislocation of proximal end of tibia, left knee, initial encounter |
| S83.116A | Anterior dislocation of proximal end of tibia, unspecified knee, initial encounter |
| S83.121A | Posterior subluxation of proximal end of tibia, right knee, initial encounter |
| S83.122A | Posterior subluxation of proximal end of tibia, left knee, initial encounter |
| S83.123A | Posterior subluxation of proximal end of tibia, unspecified knee, initial encounter |
| S83.124A | Posterior dislocation of proximal end of tibia, right knee, initial encounter |
| S83.125A | Posterior dislocation of proximal end of tibia, left knee, initial encounter |
| S83.126A | Posterior dislocation of proximal end of tibia, unspecified knee, initial encounter |
| S83.131A | Medial subluxation of proximal end of tibia, right knee, initial encounter |
| S83.132A | Medial subluxation of proximal end of tibia, left knee, initial encounter |
| S83.133A | Medial subluxation of proximal end of tibia, unspecified knee, initial encounter |
| S83.134A | Medial dislocation of proximal end of tibia, right knee, initial encounter |
| S83.135A | Medial dislocation of proximal end of tibia, left knee, initial encounter |
| S83.136A | Medial dislocation of proximal end of tibia, unspecified knee, initial encounter |
| S83.141A | Lateral subluxation of proximal end of tibia, right knee, initial encounter |
| S83.142A | Lateral subluxation of proximal end of tibia, left knee, initial encounter |
| S83.143A | Lateral subluxation of proximal end of tibia, unspecified knee, initial encounter |
| S83.144A | Lateral dislocation of proximal end of tibia, right knee, initial encounter |
| S83.145A | Lateral dislocation of proximal end of tibia, left knee, initial encounter |
| S83.146A | Lateral dislocation of proximal end of tibia, unspecified knee, initial encounter |
| S83.191A | Other subluxation of right knee, initial encounter |
| S83.192A | Other subluxation of left knee, initial encounter |
| S83.193A | Other subluxation of unspecified knee, initial encounter |
| S83.194A | Other dislocation of right knee, initial encounter |
| S83.195A | Other dislocation of left knee, initial encounter |
| S83.196A | Other dislocation of unspecified knee, initial encounter |
| S83.200A | Bucket-handle tear of unspecified meniscus, current injury, right knee, initial encounter |
| S83.201A | Bucket-handle tear of unspecified meniscus, current injury, left knee, initial encounter |
| S83.202A | Bucket-handle tear of unspecified meniscus, current injury, unspecified knee, initial encounter |
| S83.203A | Other tear of unspecified meniscus, current injury, right knee, initial encounter |
| S83.204A | Other tear of unspecified meniscus, current injury, left knee, initial encounter |
| S83.205A | Other tear of unspecified meniscus, current injury, unspecified knee, initial encounter |
+57 more billable codes in this family — see the official CMS ICD-10-CM files for the complete set.
Reading these codes correctly
- Laterality is inside the code. Many families end in 1 (right), 2 (left), and sometimes 3 (bilateral) or 9 (unspecified). Payers increasingly deny “unspecified side” when a sided code exists — capture right vs. left on the very first phone call.
- Injury (S) codes need a 7th character. The tables below show initial encounter (A) codes. The same code exists with D (subsequent encounter) for routine follow-up care and S (sequela) for late effects. A follow-up visit billed with an “A” code is a mismatch.
- Codes update every October 1. These tables are from the official FY2026 ICD-10-CM release (public domain, NCHS/CMS). Verify against the current year's files before billing.
Where the phone call fits
Every code on this page starts as a sentence a patient says on the phone. ClinicFlow's scheduling agent captures the complaint, the side, and the duration on the first call and writes it into the EMR — so intake, scheduling, and coding tell the same story. See how it works for orthopedic practices, or hear it live: (281) 502-8583.
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Educational reference, not coding advice. Descriptions are reproduced from the official FY2026 ICD-10-CM code files published by NCHS/CMS (US government work, public domain).
Frequently asked questions
What is the ICD-10 code for knee osteoarthritis?
Unilateral primary osteoarthritis of the knee is M17.11 for the right knee and M17.12 for the left. M17.0 covers bilateral primary osteoarthritis. Payers expect the sided codes when the side is known rather than M17.9 (unspecified).
What is the ICD-10 code for an ACL tear?
ACL sprains and tears live in the S83.51- family (sprain of anterior cruciate ligament), branching by knee side, with a required 7th character: A for the initial encounter, D for routine follow-up care, S for sequela.
Why do meniscus codes have so many variants?
The M23 family encodes which meniscus (medial or lateral), which zone (anterior horn, posterior horn, or other), and which knee — so one clinical idea, a degenerative meniscus tear, fans out into many billable codes. Current tears from an injury are coded in S83.2- instead.
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