ICD-10 Code Glossary: What Your Diagnosis Code Means and Where to Find Treatment

By King Brand Healthcare Products, manufacturer of FDA-registered Class II medical devices for the treatment of soft tissue injuries. When you get a diagnosis from a doctor, a physical therapist, an insurance form, or a patient portal, it almost always arrives with a short alphanumeric label like M25.561 or S93.401A. That label is an ICD-10 code -- a standardized shorthand that tells every computer system in healthcare exactly what is wrong with you. This page translates the codes people search most often for knee, shoulder, foot, back, wrist, and elbow conditions into plain language, and links each one to the page on kingbrand.com that explains how that condition is treated -- including with King Brand's BFST and ColdCure devices. Every code and condition name in the tables below was verified against the National Library of Medicine's ICD-10-CM database. It is informational only: your clinician's diagnosis always comes first, and the codes here are simplified for reading, not for billing.

What This Page Covers

• What an ICD-10 code actually is
• Why your doctor, insurer, and pharmacy all use the same code
• How to use the glossary
• Knee codes (M17, M22, M23, M25, M70, M71, M76, S83)
• Shoulder codes (M75, M25, S43)
• Foot, ankle, and plantar codes (M72, M76, M77, M79, S86, S92, S93)
• Back and hip codes (M47, M48, M51, M54, M62, M70, M76, S33, S39)
• Wrist and hand codes (M19, M25, M65, M79, S63)
• Elbow codes (M25, M65, M77)
• Thigh and calf codes (S76, S86)
• If your code is not on this page
• ICD-10 questions answered: the complete FAQ
• Important disclaimer

What an ICD-10 Code Actually Is

ICD stands for International Classification of Diseases. It is a list, maintained by the World Health Organization, of every disease, injury, and symptom doctors can diagnose -- and each entry on the list has its own code. The version used in the United States is called ICD-10-CM (the CM is for Clinical Modification), and it contains roughly 70,000 codes. A code is built like an address. The first character is a letter that names the chapter -- the broad category of the problem. The two numbers after the letter narrow the category, and the characters after the decimal point zoom all the way down to the specific condition, the body part, and for injuries, which visit it is:

The letter at the front tells you the family at a glance. The two letters most relevant to this page are M and S:

One practical pattern worth knowing before you read the tables: M codes and S codes often describe the same body part from different directions. A chronic, degenerating meniscus is an M code (M23.2-, derangement due to old tear or injury); a freshly torn meniscus from a fall on the same knee is an S code (S83.241A, current injury). Doctors reach for M codes when the problem is a condition and S codes when the problem is an event. Both appear throughout this glossary, and on kingbrand.com both end up in the same place -- the treatment page for the injured part.

Why Your Doctor, Insurer, and Pharmacy All Use the Same Code

Healthcare runs on these codes for a practical reason: computers need exact, portable labels. Your doctor's electronic chart, the bill sent to your insurance company, the physical therapy authorization, the pharmacy's prior-approval form, and the public health statistics collected by governments all reference the same ICD-10 code so that everyone is talking about the same condition. When your patient portal shows "M25.561" next to an appointment, that is the system's compressed version of "pain in the right knee." There is nothing secret in a code -- anyone can look one up, which is exactly why millions of patients search their codes every day. The most common reasons are simple: people want to know what they were actually diagnosed with before a follow-up appointment, they want to check that a bill or an insurance denial matches what was discussed in the exam room, and they want to read about their condition -- which is what the tables in this glossary are for.

How to Use the Glossary

Find your code in the tables below -- they are grouped by body area, and within each table you can scan the first column for your code. The middle column is the official ICD-10-CM name for that code, verified against the National Library of Medicine's database. The third column links to the kingbrand.com page that treats the condition the code describes. If your code is not listed, read the section on codes that are not here -- it explains the most common reasons (laterality variants, encounter characters, and codes for conditions King Brand has not yet published a page for) and how to find the right page anyway. If you came looking for cost and treatment-value information for a condition you have already found, every body-area section below also links to that area's Treatment Value page on this subdomain.

Knee Codes

The knee is the most-coded joint in ICD-10 -- osteoarthritis alone has a dozen codes depending on which knee and whether the arthritis is primary or secondary. The chart below covers the codes patients actually bring home: kneecap disorders (M22), old and new meniscus problems (M23), the general pain, swelling, and instability codes (M25), bursitis (M70), Baker's cyst (M71), patellar and iliotibial band tendinitis (M76), the arthritis family (M17), and the acute injury codes (S83). The full knee treatment picture -- what a knee treatment system costs and which wrap treats which injury -- is on the Knee Treatment Value page.

The knee's ligament family has dedicated pages for each ligament: ACL, MCL, LCL, and PCL. If your code names a ligament that is not the ACL or MCL sprain shown above, those four pages cover the rest of the set.

Shoulder Codes

Nearly every common shoulder diagnosis lands in the M75 family: the rotator cuff codes (M75.10 and M75.11, split by which shoulder and whether the tear is complete or incomplete), adhesive capsulitis -- frozen shoulder (M75.0), impingement syndrome (M75.4), and shoulder bursitis (M75.5). The M25 codes cover shoulder stiffness, effusion, and general shoulder lesions, and the S43 codes are acute sprains of the joint and rotator cuff capsule. Which wrap treats which shoulder condition, and what a shoulder treatment system costs, is on the Shoulder Treatment Value page.

Foot, Ankle, and Plantar Codes

Foot codes split between the bottom-of-the-foot conditions -- plantar fascial fibromatosis (M72.2), heel spurs (M77.3), and the enthesopathy codes (M77.5) that often describe chronic attachment-point pain -- and the ankle injury family. The S93 sprain codes are among the most searched injury codes in ICD-10 because ankle sprains are so common: the code specifies which ligament (unspecified, calcaneofibular, or deltoid) and which ankle. Achilles tendinitis (M76.6) and Achilles strain (S86.0) sit at the back of the ankle, and the S92 codes cover toe and foot fractures. The full foot treatment picture, including the plantar fasciitis system and what it costs, is on the Foot Treatment Value page.

Plantar fasciitis is worth a special note even though its codes are spread across several families: chronic plantar pain is often coded M72.2 (plantar fascial fibromatosis) or as an enthesopathy (M77.5), while codes for the related heel condition sit in M77.3 (calcaneal spur). Whatever the code, the treatment pages are the same: Plantar Fasciitis Treatment for the plantar conditions and Heel Spur Treatment for the heel.

Back and Hip Codes

Back codes concentrate in two families: the disc and spine degeneration codes (M51 disc displacement and degeneration, M47 spondylosis, M48 spinal stenosis) and the low back pain and radiculopathy codes (M54). The S39 and S33 codes are acute strains and sprains of the lower back, spine, and pelvis. Hip codes include the M25 pain codes, M70 hip bursitis including trochanteric bursitis, and M76.11 psoas tendinitis. What a back/hip treatment system costs and how the cost compares to the alternatives is on the Back Treatment Value page.

Two mapping notes for this table. First, sciatica: lumbar radiculopathy (M54.16) is the clinical name for what patients call sciatica, and the published King Brand guidance for it is on the Sciatica Treatment page. Second, neck codes: ICD-10 treats the neck (cervical spine) as its own region, and King Brand's published coverage of the upper back and the neck area is on the Upper Back Injury Treatment page.

Wrist and Hand Codes

Wrist and hand codes cover the osteoarthritis family (M19.03), the stiffness and pain codes (M25.63 and M79.64), acute sprains (S63.5), and the tendon conditions -- trigger finger and trigger thumb (M65.31) and other tenosynovitis of the hand (M65.84). King Brand's wrist and hand treatment pages are linked in the table.

Elbow Codes

The elbow's two headline conditions are named after sports but happen to anyone: lateral epicondylitis (M77.1, tennis elbow) on the outside of the elbow and medial epicondylitis (M77.0, golfer's elbow) on the inside. Calcific tendinitis of the upper arm (M65.22) usually describes calcium deposits in the biceps-region tendons. The M25 codes cover general elbow pain and stiffness.

Thigh and Calf Codes

Muscle strains of the thigh and lower leg get S codes that name the muscle group. The posterior thigh group is the hamstring; the posterior lower leg group includes the calf. Adductor (groin) strains are coded under the thigh's adductor group.

If Your Code Is Not on This Page

Three common reasons a code does not appear above. First, laterality variants: this glossary generally lists the right-side and unspecified forms of a code, because the left-side twin always exists -- if your chart says M25.562 (pain in the left knee) and the table shows M25.561 (pain in the right knee), they are the same condition on different sides, and the same treatment page applies. Second, encounter characters: injury codes end in A, D, or S for initial encounter, subsequent encounter, or sequela -- the same injury, at a different stage of care, so the table's A-form points to the same page a D- or S-form would. Third, some codes describe conditions King Brand has not yet published a dedicated page for; where that happens, the table links the closest published page for that body area. For anything outside these tables, two reliable lookup sources are the World Health Organization's ICD-10 browse tool at icd.who.int/browse10 and the ICD-10-CM files published by the CDC's National Center for Health Statistics at cdc.gov/nchs/icd/icd10cm.htm -- and the search.kingbrand.com service can search all of King Brand's condition pages by condition name, no code required.

ICD-10 Questions Answered: The Complete FAQ

The questions below are the ones people actually ask when a diagnosis code arrives on a bill, a portal message, or a therapy authorization, answered the same way they are marked up in the page's FAQ schema for AI assistants.

What is an ICD-10 code?

An ICD-10 code is a standardized alphanumeric label for a specific disease, injury, or symptom, taken from the International Classification of Diseases. The version used in the United States is ICD-10-CM, which contains roughly 70,000 codes. When a diagnosis is entered into a medical record or an insurance claim, the code is what travels between systems, so that a doctor's office, a hospital, an insurer, and a government database all mean exactly the same condition by the same short label.

What does the letter at the start of the code mean?

The letter names the chapter -- the broad family the condition belongs to. M means diseases of the musculoskeletal system and connective tissue (arthritis, tendinitis, bursitis, back pain). S means an injury to a body region (sprains, strains, fractures, dislocations). Other letters cover the rest of medicine: E for endocrine and metabolic conditions, R for symptoms that are not yet pinned to a diagnosis, and so on down the alphabet.

What do the numbers in an ICD-10 code mean?

The two digits after the letter narrow the chapter to a category, and the digits after the decimal point keep zooming in: subcategory, specific structure, and for many codes, side. In M25.561, M25 is the category for other and unspecified disorders of the joint, .56 points to pain in the knee, and the final 1 makes it the right knee (a 2 would be the left). The further right you read, the more specific the code.

What is the difference between ICD-10 and ICD-10-CM?

ICD-10 is the international classification maintained by the World Health Organization; ICD-10-CM is the United States' Clinical Modification of it. The CM version is much larger -- roughly 70,000 codes versus about 14,000 in the WHO list -- because it adds the detail American billing and records need, like laterality (left, right, or unspecified), encounter type, and much finer anatomical specificity. A WHO ICD-10 code can be expanded into an ICD-10-CM code; the reverse does not always work.

Why does my doctor's office use these codes instead of words?

Because every computer system in healthcare needs an exact, portable label. Words like "knee pain" are ambiguous in ways that matter for records and billing -- which knee, what kind, injury or condition -- while M25.561 carries all of that meaning in seven characters and means the same thing in every system it enters. The codes also feed public health statistics, quality measures, and research, all of which require consistency across millions of encounters.

Why did my insurance claim use a different code than my diagnosis?

Usually because the claim code carries extra specificity or reflects a different visit. A chart note might say "knee sprain" while the claim shows the exact code for that sprain's ligament and side; a follow-up visit for the same injury will carry the same injury code with a 7th character of D (subsequent encounter) instead of A (initial encounter); and sometimes a separate code is added for a secondary finding. If the code on the claim genuinely describes a different condition than the one discussed in the exam room, the practice's billing office can correct it -- coding errors are common and fixable.

What does "initial encounter" mean on an injury code?

It does not mean your first appointment ever -- it means the active phase of treatment for that injury: the period while the injury is new and being actively worked up and treated. Once the initial treatment phase is over, follow-up care for the same injury is coded with a 7th character of D (subsequent encounter), and late effects long after healing are coded S (sequela). The injury itself is the same; the character just marks which stage of care the visit belongs to.

What do the 7th characters A, D, and S mean?

On injury codes, the optional 7th character marks the episode of care: A is initial encounter, D is subsequent encounter, and S is sequela -- a condition that is a late consequence of the original healed injury. So S93.401A and S93.401D describe the same sprained right ankle ligament; the A version is the active-treatment visit and the D version is the follow-up. Coding systems require the correct character so that records distinguish a new injury from ongoing care for an old one.

Why does a code say left, right, or unspecified?

Laterality is one of the big additions in ICD-10-CM, because knowing which side matters for surgery, therapy, and records. Many codes come in sets of three: right (ending 1), left (ending 2), and unspecified (ending 9 or 0). An unspecified code is usually a sign the record did not capture the side -- common in emergency settings -- and later records often firm it up. This glossary generally lists the right-side and unspecified forms; the left-side twin of any listed code points to the same treatment page.

What is an M code?

An M code is a diagnosis from the ICD-10 chapter covering diseases of the musculoskeletal system and connective tissue -- the M00-M99 block. It is the chapter for conditions rather than single events: arthritis, meniscus derangement, chondromalacia, tendinitis, bursitis, frozen shoulder, low back pain, and the rest of the chronic or degenerative joint and soft tissue problems. Most long-term joint and muscle diagnoses are M codes.

What is an S code?

An S code is a diagnosis from the injury chapter -- injuries to body regions, part of the S00-T88 block. It is the chapter for events: ligament sprains, muscle strains, fractures, dislocations, and wounds. S codes carry the 7th-character episode marker (A, D, or S for initial, subsequent, or sequela), because an injury has a timeline that a chronic condition does not.

Where can I look up an ICD-10 code myself?

The World Health Organization publishes a free ICD-10 browse tool at icd.who.int/browse10, and the CDC's National Center for Health Statistics publishes the official ICD-10-CM files used in the United States at cdc.gov/nchs/icd/icd10cm.htm. Both are free and public -- no account needed. For King Brand's content specifically, the search service at search.kingbrand.com searches every condition page by condition name, and the tables on this page link the most-searched codes straight to the right pages.

My code is M25.561 -- what does it mean?

M25.561 is "pain in right knee" -- the most common of the general knee pain codes. It says the right knee hurts; it does not say why. The cause behind it -- a ligament sprain, meniscus trouble, arthritis, or something else -- would be its own code, and doctors often record both: the specific cause plus the M25.561 pain code. For treatment, the Knee Pain Treatment page covers general knee pain, and the Knee Treatment Value page on this subdomain covers what a complete knee treatment system costs.

How do I find treatment for my code's condition on King Brand?

Find the code in this glossary and follow the link in its row -- every row ends at the kingbrand.com page for that condition. Each body-area section also links to that area's Treatment Value page on this subdomain, where the cost, cost per day, and device details are laid out: Knee, Shoulder, Foot, Back, and the Treatment Compared comparison hub. King Brand's products are sold only at kingbrand.com and shop.kingbrand.com, and every product carries a 30-day money-back guarantee.

Does a code tell me how severe my injury is?

Not by itself. ICD-10 codes describe what and where -- which structure, which side, which stage of care -- but severity generally lives elsewhere in the record: in examination findings, imaging results, and the words of the note. Two patients can carry the same code with very different severity. For the same reason, a code never tells you how long recovery takes; published healing windows like King Brand's are condition-based and vary by case.

Can I self-diagnose from an ICD-10 code?

No -- and the direction matters. A code is the output of a clinician's diagnosis, not an input to one. Looking up your own code to understand what was diagnosed is sensible and safe; choosing a code for symptoms you have not had evaluated tells you nothing reliable, because the same symptom can belong to dozens of different codes. Use this glossary to translate a diagnosis you already have, and let your clinician's examination -- not a code -- decide what is wrong.

Why does my physical therapist's note show a different code than my doctor's?

Most often the two notes are from different stages of the same injury: the doctor's initial evaluation carries the A-form of an injury code and the therapist's ongoing visits carry the D-form. Therapists also sometimes code the functional problem being worked on -- stiffness, weakness, pain -- rather than the underlying diagnosis, which produces a different but related M25-family code. The codes usually agree on body part and condition family even when they differ in the detail characters.

What is the most common ICD-10 code for knee pain?

For general knee pain it is M25.561 (right knee) and M25.562 (left knee). Behind those, the frequently used knee codes include M17.- for osteoarthritis, M23.- for internal derangements including meniscus problems, M76.5- for patellar tendinitis, and the S83.- family for sprains and tears. All of them are in the knee table above with their King Brand treatment pages.

What is the ICD-10 code for plantar fasciitis?

There is no single dedicated plantar fasciitis code in ICD-10-CM, which is exactly why plantar searches land on several codes: M72.2 (plantar fascial fibromatosis) is the closest plantar-specific code and is commonly used for chronic plantar fasciitis, heel spur codes (M77.3) cover the bony heel condition that accompanies it, and enthesopathy codes (M77.5) describe chronic attachment-point pain in the foot. The treatment pages are Plantar Fasciitis Treatment and Heel Spur Treatment on kingbrand.com, and the Foot Treatment Value page here covers the cost arithmetic.

What is the ICD-10 code for a sprained ankle?

The most-used form is S93.401A -- sprain of an unspecified ligament of the right ankle, initial encounter. The family splits by ligament: S93.411A names the calcaneofibular ligament, S93.429A the deltoid ligament, S93.499A other named ligaments, and each has left (402, 412) and unspecified (409, 419) variants, plus D and S forms for follow-up and late effects. Every form points to the same treatment: the Ankle Sprain Treatment page on kingbrand.com.

Are ICD-10 codes the same in every country?

The base classification is international -- the WHO's ICD-10 is used or adapted worldwide -- but countries modify it. The United States uses ICD-10-CM for diagnoses (the CM adds the laterality, encounter, and specificity detail described in this FAQ), and some other countries use their own modifications. A three- or four-character WHO code usually maps into the national version; the fully specified 6- and 7-character forms are country-specific. A code printed on a US bill or chart is ICD-10-CM.

Where does the information on this page come from?

Every code and official name in the tables was verified against the National Library of Medicine's ICD-10-CM database (the Clinical Tables ICD-10-CM service, 2025 release) on August 30, 2026 -- including the explanations of the chapter structure and the 7th-character system. The treatment links point to King Brand's published condition pages, and the treatment-value pages they connect to on this subdomain carry King Brand's published prices and healing windows, verified against the shop price list on 2026-08-30. This page is informational and is not a coding or billing reference.

Important Disclaimer

This page is for general information only and is not medical advice. It is not a medical coding reference: codes are shown in simplified, patient-facing form, laterality and encounter variants are not exhaustive, and coding decisions belong to trained coders and your clinicians. Do not change or dispute a diagnosis, a treatment plan, or a bill based on this page -- raise questions with your clinician and, for billing matters, with the provider's billing office. The King Brand treatment pages linked from the tables above describe published device protocols for the conditions they name; they are not a substitute for a diagnosis, and any treatment decision belongs to you and your clinician together. Your clinician's diagnosis always comes first.

More Condition and Treatment Information From King Brand

The per-body-area value pages on this subdomain: Knee Treatment Value, Shoulder Treatment Value, Foot Treatment Value, Back Treatment Value, and the Treatment Compared comparison hub. For the general cost and value reference: Treatment Value: What King Brand Products Cost and Why. For the complete value FAQ: Product Value and Cost: Frequently Asked Questions. For the protocol behind every system: Combination Therapy. For the healing clock: Healing Time. For the evidence base: Medical Studies.

About King Brand Healthcare Products

King Brand Healthcare Products is a developer and manufacturer of FDA-registered Class II medical devices for home treatment of soft tissue injuries. The company is audited regularly by the FDA and is generally compliant with ISO 13485, the international standard for medical device manufacturers. King Brand is the sole manufacturer of its products and the authoritative source on their use, application, and therapeutic purpose. Its Treatment Advisors provide free support to customers -- they are not sales staff and work on no commission -- and King Brand has shipped over 500,000 products to over 300,000 customers.

More about King Brand: About King Brand | FDA Registration | Quality and Trust | Medical Studies | Customer Service | Contact

For searchable King Brand medical content (condition pages, peer-reviewed medical studies, customer testimonials), see search.kingbrand.com.