The VA disability rating system assigns a percentage to service-connected conditions that reflects the severity of the impairment. This percentage determines the level of monthly compensation a veteran receives. For knee pain and related joint issues, the process is detailed and focuses heavily on measurable physical limitation. Understanding the specific criteria the VA uses to evaluate the knee joint is essential for veterans filing a claim.
Understanding Functional Impairment
The foundation of musculoskeletal ratings for conditions like knee pain rests on the principle of functional impairment. This means the VA rates the inability to use the joint effectively, not just the existence of a diagnosis or the veteran’s subjective feeling of pain. The central question is how the knee condition limits the body’s normal working movements, including excursion, strength, speed, coordination, and endurance.
This functional loss must be documented during a Compensation and Pension (C&P) examination by a VA-assigned clinician. The exam evaluates the degree to which the knee condition interferes with a veteran’s daily activities. While a diagnosis like arthritis or a torn ligament is necessary, the rating percentage flows primarily from the measurable loss of function caused by that diagnosis, including how frequently flare-ups occur. A rating is considered “compensable” when the percentage is 10% or higher.
Rating Common Knee Conditions
Instability or laxity of the knee joint, which occurs when ligaments are damaged, is rated based on its severity and the need for external support. A mild case might receive a 10% rating, while a severe case that requires both a prescribed brace and an assistive device for walking can reach a 30% rating.
Total knee replacement surgery, rated under Diagnostic Code 5055, has a specific set of rules. For four months immediately following the procedure, the VA assigns a 100% temporary rating for recovery. Following this period, the veteran receives a minimum permanent rating of 30%. If the residual symptoms are severe, involving marked weakness or painful motion, the permanent rating can be as high as 60%.
Conditions like arthritis (often secondary to trauma) and meniscal issues are often rated based on the limitation of motion they cause. If chronic arthritis does not limit range of motion but is confirmed by X-ray evidence, it may be rated at 10% or 20%. If the arthritis leads to joint stiffness, or ankylosis, the rating criteria shift to the fixed angle of the knee, with ratings ranging from 30% to 60% depending on the severity of the immobility.
The Critical Role of Range of Motion
The measurable limitation of the joint’s range of motion (ROM) is the most common factor driving the final knee disability percentage. A clinician uses a goniometer to precisely measure two primary movements: flexion (bending the knee) and extension (straightening the leg). Normal flexion typically reaches about 140 degrees, and the knee should be able to extend fully to zero degrees.
Limited flexion is rated based on how far the knee can bend. For example, if flexion is limited to 45 degrees, a 10% rating is assigned, but if it is limited to 15 degrees or less, the rating increases to 30%. Limited extension is measured by how far the knee is prevented from fully straightening. Ratings for extension limitation begin at 10% for a 10-degree limitation and can rise to 50% if the leg is fixed at a 45-degree angle. It is possible to receive separate ratings for both limited flexion and limited extension on the same knee, which the VA combines using a specific mathematical formula to arrive at the final percentage.
Adjustments for Pain and Bilateral Claims
The presence of pain can significantly influence the final rating, even beyond the specific degree of motion. The VA’s “painful motion” rule mandates that if a service-connected joint is painful during movement, the veteran must be awarded at least the minimum compensable rating for that joint. For the knee, this means a minimum of 10% must be assigned, even if range of motion measurements are otherwise normal.
When a veteran has service-connected conditions in both knees (a bilateral claim), the VA recognizes the compounded effect on mobility. When ratings for both legs are combined, the VA applies a “bilateral factor,” which adds an additional 10% of the combined value to the total rating. This formula compensates for the increased functional handicap of having two disabled limbs.
The rule against pyramiding prevents the VA from rating the same functional limitation multiple times under different diagnostic codes. For example, a veteran cannot receive a rating for limited range of motion and a separate rating for arthritis if the arthritis is the sole cause of that motion limitation.