Radiology glossary

What does "chondromalacia patella" mean on your scan?

Part of: Knee findings, explained

Full explainer: Chondromalacia Patella — What It Means on Your Report

The cartilage on the underside of the kneecap has softened or worn — an early stage of cartilage wear behind the patella. The kneecap glides in a groove at the front of the thigh bone, cushioned by some of the thickest cartilage in the body; when that cartilage softens, frays, or thins — from overuse, misalignment, muscle imbalance, or injury — radiologists call it chondromalacia, literally “soft cartilage.” It is often described in grades, from softening alone to fissuring and eventually exposed bone, and it is a frequent finding in active adolescents and young adults as well as in older adults with arthritis. The classic symptom is aching around or behind the kneecap, often worse with stairs, squatting, or sitting long with bent knees — the so-called “moviegoer's knee.” But like most cartilage findings, it is also common in people with no pain, so the grade on the report is only meaningful alongside your symptoms. It is best understood as a description of the kneecap cartilage's condition, not a verdict on your knee's future.

What it means on CT

CT is not the usual test for cartilage softening — cartilage is barely visible on it. CT can be useful for the bony mechanics: the shape of the trochlear groove, the kneecap's position, and measurements of alignment that contribute to cartilage wear. When the question is “why is this cartilage wearing,” CT's bony detail helps; when the question is “how worn is it,” MRI answers.

What radiologists look at next

For chondromalacia patella, the radiologist examines the patellar cartilage on MRI slice by slice, noting softening, fissuring, thinning, or full-thickness defects and assigning a grade from early softening to exposed bone. They assess the kneecap's tracking — its tilt and position within the trochlear groove — and the groove's shape, since maltracking drives the wear. Associated findings are documented: joint effusion, bone marrow edema beneath damaged cartilage, and any loose fragments. The location of the worst wear (inner facet, outer facet, or ridge) is specified, because it correlates with the mechanics and with where patients typically feel pain.

Where it commonly shows up

• kneecap
• patella
• front of the knee
• right knee
• left knee

Questions to ask your doctor

• What grade is the cartilage wear, and what does that grade mean?
• Is my kneecap tracking properly in its groove?
• Could this explain my pain with stairs or squatting?
• Will the cartilage wear keep progressing?
• What can I do to protect the cartilage?

Common questions

What does chondromalacia feel like?

Typically a dull ache around or behind the kneecap, often worse going up or down stairs, squatting, kneeling, or sitting a long time with bent knees. Some people notice grinding or clicking. The pattern — pain with loaded bending — is characteristic, but your doctor confirms whether the cartilage finding explains your symptoms.

Is chondromalacia the same as arthritis?

It is an early stage on the same spectrum: chondromalacia describes softening and fraying of the cartilage, while arthritis implies more established wear with joint changes. Mild chondromalacia in a young person is often an overuse or tracking issue rather than the beginning of inevitable arthritis. Your doctor can put the grade in context.

Can the cartilage heal?

Cartilage has a poor blood supply, so damaged cartilage does not regenerate like skin — but symptoms very often improve with activity modification, strengthening of the surrounding muscles (especially the quadriceps), and time, even though the MRI appearance changes little. Treatment targets how the knee feels and functions, not the picture.

What does the grade on my report mean?

Radiologists usually grade chondromalacia from I to IV: grade I is softening of the cartilage, grade II is shallow fissuring or fraying, grade III is deeper fissures reaching more than half the cartilage thickness, and grade IV is full-thickness loss with exposed bone underneath. The grade describes the worst area seen on MRI, not the whole kneecap, and small grade I–II changes are extremely common and often painless. What correlates best with symptoms is not the grade alone but the combination of grade, location, swelling, and bone edema beneath the worn cartilage — which is why two reports with the same grade can mean very different things clinically. Ask your doctor how your grade fits your examination.

Related conditions

• Osteoarthritis — What It Means on Your Report
• Meniscal Tear — What It Means on Your Report
• Patellar Tendinopathy — What It Means on Your Report