Usefulness of patellar cartilage cross-sectional area for knee tibiofemoral osteoarthritis in elderly

Figures & data

Table 1 Comparison of the characteristics of control and KOA group

Variable	Control group, n=77	KOA group, n=88	Statistical significance
Gender (male/female)	23/54	20/68	p=0.134
BMI (kg/m^2)	29.1±4.8	28.9±4.3	p=0.327
Age (yrs)	57.13±8.19	58.28±6.67	p=0.357
PCA (mm^2)	98.66±22.18	59.43±16.11	p<0.001

Note: Data represent the mean ± standard deviation or the numbers of patients.

Abbreviations: KOA, knee tibiofemoral osteoarthritis; BMI, body mass index; PCA, patellar cartilage cross-sectional area; NS, not statistically significant (p>0.05).

Figure 1 Measurement of the patellar cartilage cross-sectional area (PCA) on transverse turbo spin echo fat-suppressed T2-weighted image. (A) Control group. (B) Knee tibiofemoral osteoarthritis group.

Table 2 Age distribution of patients with mean PCA of control group

Age distribution (years)	Total (N)
50–59	97.92±22.39 mm^2 (54)
60–69	101.22±18.91 mm^2 (15)
70–79	98.92±28.48 mm^2(8)

Abbreviation: PCA, patellar cartilage cross-sectional area.

Table 3 Age distribution of patients with mean PCA of KOA group

Age distribution (years)	Total (N)
50–59	57.79±14.98 mm^2 (52)
60–69	61.96±18.28 mm^2 (32)
70–83	60.38±12.07 mm^2 (4)

Abbreviations: PCA, patellar cartilage cross-sectional area; KOA, knee tibiofemoral osteoarthritis.

Table 4 Sensitivity and specificity of each cutoff point of the PCA

PCA (mm^2)	Sensitivity (%)	Specificity (%)
42.81	19.3	100
61.84	53.4	98.7
71.66	75.0	90.9
76.06^a	83.0	83.1
81.38	89.8	75.3
87.39	96.6	66.2

Note: ^aThe best cutoff point on the receiver operating characteristic (ROC) curve.

Abbreviation: PCA, patellar cartilage cross-sectional area.

Figure 2 Receiver operating characteristic (ROC) curve of patellar cartilage cross-sectional area (PCA) for prediction of knee osteoarthritis. The best cutoff point of PCA was 76.06 mm², with sensitivity of 83.0%, specificity of 83.1% and AUC of 0.94. PCA AUC (95% CI) =0.94 (0.90–0.97).

Abbreviation: AUC, area under the curve.