The medical term is total knee arthroplasty

The medical term for knee replacement is total knee arthroplasty, often shortened to TKA. Arthroplasty means surgical repair or replacement of a joint, and "total" indicates that the surgeon replaces all three compartments of the knee — the surfaces where the thighbone, shinbone, and kneecap meet.

You may also hear the term total knee replacement (TKR) used interchangeably by doctors and in medical records. Both terms refer to the same procedure. Some surgeons use knee arthroplasty without the word "total" when discussing the operation, though this is less precise because partial knee replacements exist as a separate procedure.

The procedure involves removing the damaged cartilage and bone from the ends of the thighbone, shinbone, and kneecap, then fitting metal and plastic components in their place. A surgeon typically performs this under general anesthesia and the operation takes about one to two hours.

Key Takeaways

  • Total knee arthroplasty (TKA) is the official medical name for full knee replacement surgery.
  • The term "total" means all three knee compartments are replaced, not just one or two.
  • Total knee replacement (TKR) is another common way doctors refer to the same procedure.
  • Partial knee replacement, or unicompartmental knee arthroplasty, is a different procedure that replaces only one section of the knee.
  • Medical records and insurance documents will use these formal terms rather than the word "replacement" alone.

Why doctors use the term arthroplasty

The word arthroplasty comes from Greek roots: "arthro" means joint and "plasty" means to shape or form. Surgeons use this term for any procedure that reshapes or reconstructs a joint, whether by repair, realignment, or replacement. You will see arthroplasty used for hip, shoulder, and ankle procedures as well.

The word "total" matters because it tells you the scope of the surgery. A partial knee arthroplasty (also called unicompartmental knee arthroplasty or UKA) replaces only the damaged section of the knee, usually the inner or outer compartment. A total knee arthroplasty replaces all three weight-bearing surfaces. Your surgeon will recommend one or the other based on where the damage is located and how much cartilage has worn away.

What you will see on medical documents

When you receive paperwork from your surgeon, hospital, or insurance company, look for the code CPT 27447 (for unilateral total knee replacement) or ICD-10 code Z96.651 (for a knee replacement that has already been done). These codes standardize the procedure across hospitals and insurance systems so that records are consistent no matter where you receive care.

Your surgical consent form will likely use the phrase "total knee arthroplasty" or "total knee replacement" in the description of what the surgeon will do. Insurance pre-authorization letters will use one of these terms as well. If you see only the word "arthroscopy" on a document, that is a different procedure — arthroscopy is a minimally invasive diagnostic or repair procedure, not a replacement.

Partial knee replacement uses a different term

If your surgeon recommends replacing only part of your knee, they will use the term unicompartmental knee arthroplasty (UKA) or partial knee replacement. "Unicompartmental" means one compartment. This procedure is an option when damage is limited to one area of the knee and the other compartments are still healthy.

Partial knee replacement involves a smaller incision, less bone removal, and a shorter recovery than total knee replacement. However, not all knees are candidates for this approach. Your surgeon will order imaging — usually X-rays or an MRI — to determine whether the damage is confined to one compartment or spread across multiple areas.

Revision knee replacement has its own term

If you have already had a knee replacement and the implant wears out or fails, a second surgery is called a revision total knee arthroplasty or revision knee replacement. The surgeon removes the old implant and installs a new one. This procedure is more complex than a first replacement because the surgeon must work around scar tissue and may need to use special implants or bone grafts.

Revision surgery takes longer than a primary replacement and recovery is typically slower. Your surgeon will discuss whether a revision is necessary based on imaging and your symptoms. Some implants last 15 to 20 years or longer, so not everyone who has a knee replacement will need a revision.

Related surgical terms you might hear

Your surgeon may mention other terms depending on your specific situation. Knee arthroscopy is a diagnostic or repair procedure using a small camera and instruments inserted through tiny cuts — it is not a replacement. Knee osteotomy is a procedure that realigns the knee by cutting and repositioning bone, often used to delay replacement in younger patients. Knee fusion (arthrodesis) permanently locks the knee joint and is used only in severe cases where replacement is not an option.

If your surgeon mentions any of these terms, ask them to explain how it differs from total knee arthroplasty and why they are recommending it for your situation. Understanding the exact procedure planned helps you prepare mentally and physically for surgery and recovery.

Frequently Asked Questions

Is total knee arthroplasty the same as total knee replacement?

Yes. Total knee arthroplasty (TKA) and total knee replacement (TKR) are two names for the same procedure. Doctors use both terms interchangeably. Arthroplasty is the formal medical term, while replacement is the more common way patients and some doctors describe it.

What does the word total mean in total knee arthroplasty?

Total means the surgeon replaces all three weight-bearing surfaces of the knee: where the thighbone meets the shinbone, where the thighbone meets the kneecap, and where the shinbone meets the kneecap. A partial knee replacement replaces only one of these areas.

Will my insurance use the term arthroplasty or replacement?

Insurance companies use both terms, but they rely on procedure codes (CPT and ICD-10) to process claims. Your pre-authorization letter may say either "total knee arthroplasty" or "total knee replacement." Both refer to the same surgery and will be covered the same way.

Is knee arthroscopy the same as knee replacement?

No. Knee arthroscopy is a minimally invasive diagnostic or repair procedure using a small camera. Knee replacement (arthroplasty) removes damaged bone and cartilage and installs an implant. They are two different procedures with different recovery times and outcomes.

What is the difference between primary and revision knee arthroplasty?

Primary knee arthroplasty is your first knee replacement. Revision knee arthroplasty is a second surgery performed when the first implant wears out or fails. Revision surgery is more complex and takes longer to recover from than a primary replacement.