In 1993, Medicare developed the K Level assignments to categorize the activity level of all lower extremity amputees.  The levels describe the types of activities a patient can perform and ultimately determines the eligibility and coverage for certain lower extremity prosthetic components. A user’s daily needs, hobbies and occupation are all taken into consideration to help formulate the user’s prosthetic recommendation.

Currently, activity levels are subjectively determined through the collaboration of the medical team. Prosthetists, physicans, physical therapists and case managers determine K Levels based on a user’s:

Medical History

Pre-Amputation Activity Level

Post-Amputation Activity Level

Expected or Potential Activity Level after receipt of prosthesis

It is important to note that a patient’s age, use of an assistive device, such as a cane or walker, or specific level of amputation do not exclude users from certain K level ratings. Occasionally, strength and agility tests are utilized to help the team determine the appropriate activity level.  There are 5 K level classifications:

KO Level

A patient at this level does not have the ability or potential to walk or transfer safely with a prosthesis. A prosthesis would not enhance this user’s quality of life or mobility.

K1 Level

A patient at this level has the ability or potential to use a prosthesis for transfers or walking on level surfaces at a single speed, typically indoors.  This patient may need the assistance of another person to safely transfer, but this person is still a prosthetic candidate. Simple, lightweight components are used for K1 prostheses.

K2 Level

This patient has the ability or potential to walk at a single speed, climbing low-level environmental barriers such as curbs, stairs, and some uneven surfaces. Some K2 users use an assistive device such as a walker or cane for safety and walk both indoors and outdoors.

K3 Level

This patient has the ability or potential to walk with a prosthesis at multiple speeds. A K3 user is able to walk on uneven ground and climb all environmental barriers such as stairs, curbs, ramps indoors and outside in the community. Many prosthetic users fall into this category. A K3 user may sometimes use an assistive device for safety.

K4 Level

A patient at this level has the ability or potential walk with a prosthesis far beyond basic walking including running and high impact activities. Often, children and athletes are classified in the K4 level.