Table 1.
Characteristics of the four groups identified by cluster analysis (mean values and standard deviations of the 8 parameters). Note that the Cobb angles are for signed values (left curve has a negative Cobb angle).
| Group 1 | Group 2 | Group 3 | Group 4 | |
|---|---|---|---|---|
| Mean (S.D.) | Mean (S.D.) | Mean (S.D.) | Mean (S.D.) | |
| Apex level (upper curve) | 6.9 (0.9) | 6.5 (1.0) | 6.4 (1.0) | 5.73 (1.5) |
| Apex level (lower curve) | 13.9 (0.9) | 13.4 (1.0) | 13.6 (1.0) | 13.0 (1.5) |
| Cobb angle (upper curve) | 26.9 (14.0) | 33.5 (16.1) | 2.4 (24.2) | 4.55 (24.5) |
| Cobb angle (lower curve) | −30.6 (15.9) | −33.3 (14.6) | 1.7 (27.0) | −7.75 (26.7) |
| Apex vertebra rotation (upper curve) | 5.0 (7.0) | 6.7 (6.8) | 2.9 (7.7) | 4.30 (7.4) |
| Apex vertebra rotation (lower curve) | −3.6 (6.2) | −7.9 (8.6) | 3.1 (6.9) | 2.84 (8.4) |
| Rotation of PMC (upper curve) (degrees) | 57.0 (19.6) | 71.7 (17.6) | −46.7 (27.9) | −60.3 (24.8) |
| Rotation of PMC (lower curve) (degrees) | 57.1 (18.9) | −73.0 (13.8) | −52.5 (21.2) | 60.9 (19.7) |
| Number of observations in group | 148 | 48 | 34 | 15 |