Sonographic evaluation of femoral trochlear cartilage in patients with knee pain.

OBJECTIVES

The purpose of this study was to investigate whether routine clinical sonographic evaluation of femoral trochlear cartilage can identify abnormalities in patients with knee pain.

METHODS

Short-axis sonograms of the femoral trochlear cartilage were obtained from 20 symptomatic knees in 20 consecutive patients (16 women and 4 men; mean age, 54 years; range, 35-75 years) and 20 knees in 10 asymptomatic control participants (7 women and 3 men; mean age, 52 years; range, 31-74 years). Articular cartilage thickness was measured at 3 locations in each knee, and thickness at each site was compared between patients and controls. Subsequently, images from patients and controls were randomly assorted and evaluated by 3 blinded musculoskeletal radiologists, who independently evaluated the femoral trochlear cartilage in each sonogram for cartilage clarity, grade, and presence or absence of cartilage calcifications, osteophytes, and subchondral bony irregularity. The radiologists were instructed to rate the most severe lesion in each evaluated region (medial trochlea, trochlear notch, and lateral trochlea). Cartilage clarity was defined as how well the cartilage borders could be distinguished from the overlying intra-articular soft tissues, and grade was defined as the severity of focal cartilaginous lesions.

RESULTS

Using the Student t test, there was no significant difference (P > .05) between cartilage thickness in patients and controls for any location measured. However, using repeated measures analysis of variance, there were significant differences (P = .02) for both decreased cartilage clarity (df = 1/28; F = 5.76) and increased grade (df = 1/28; F = 5.77) in patients. There was also a nonsignificant (P > .05) trend toward more frequent calcifications, osteophytes, and bony irregularity in patients.

CONCLUSIONS

Routine clinical sonography can identify femoral trochlear cartilage abnormalities in patients with knee pain and therefore can be a useful adjunct to other imaging tests for identifying arthritic changes in the knee.