Relationship between cartilage glycosaminoglycan content (assessed with dGEMRIC) and OA risk factors in meniscectomized patients.

OBJECTIVE: To study the relationship between cartilage integrity, assessed with [delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC)] and epidemiologic risk factors for knee osteoarthritis (OA) in meniscectomized patients. METHODS: Body mass index (BMI) was calculated in 45 patients (16 women), mean age 46, who underwent an arthroscopic medial meniscectomy 1-6 years earlier. The cartilage glycosaminoglycan (GAG) content was estimated by dGEMRIC Index and tests of isokinetic muscle strength and functional performance (one-leg hop test) were conducted. RESULTS: BMI ranged from 20.0 to 34.3 (mean: 26.5). The dGEMRIC Index was 14.4% lower in the medial index compartment (374+/-61ms, mean+/-SD) than in the lateral reference compartment (437+/-59ms, mean+/-SD) (P<0.001). The dGEMRIC Index of the medial diseased compartment correlated positively with both knee flexor (r=0.50, P=0.001) and knee extensor strength (r=0.47, P=0.001) relative to body weight and with the one-leg hop test (r=0.42, P=0.004). Furthermore, a negative correlation was found between the dGEMRIC Index of the medial compartment and BMI (r=-0.35, P=0.019). No significant correlations were found in the lateral reference compartment. CONCLUSION: The lower dGEMRIC Index of the medial compartment suggests decreased cartilage GAG content after medial meniscectomy, indicating an early stage OA. Furthermore, results suggest that overweight is a factor that deteriorates cartilage, whereas strong and co-ordinated thigh muscles may have a protective effect on the cartilage integrity.