Rating Patellofemoral Arthritis - Rating Tip of the Week

Question:
My patient has patellofemoral knee pain but the joint interval on x-ray looks normal. Does the patient have a ratable impairment?

Answer:
Possibly. Although Table 17-31 on page 544 of the Guides indicates that a cartilage interval of 2 mm or less is required for a ratable impairment for knee arthritis, do not overlook the footnote that states a 5% lower extremity impairment can be given if there is a history of direct trauma AND complaints of patellofemoral pain AND crepitation on exam. All three conditions must be met and documented to support your rating. Direct trauma requires a forceful contusion to the anterior knee over the patella. Crepitation is a common finding as we age and may be unrelated to the injury.

Apply Table 17-2 on page 526 to determine what arthritic impairment can be combined with; it cannot be combined with gait, muscle atrophy, muscle strength, or abnormal motion.

(Don’t forget to order your sunrise view x-ray at 40 degrees of flexion or a true lateral view of the knee to assess the patellofemoral joint.)