Table 3.
Classification of Patella Height by Indices for Skeletally Mature and Immature Groups
| Patellar Height Category | ISI | CDI | BPI - 0° | BPI - 5° | BPI - 10° | BPI - 15° |
|---|---|---|---|---|---|---|
| Skeletally mature group | ||||||
| Patella alta, n (%) | 17 (34%) | 3 (6%) | 7 (14%) | 6 (12%) | 4 (8%) | 3 (6%) |
| Patella baja, n (%) | 2 (4%) | 0 | 0 | 0 | 0 | 2 (4%) |
| Normal, n (%) | 31 (62%) | 47 (94%) | 43 (86%) | 44 (88%) | 46 (92%) | 45 (90%) |
| Skeletally immature group | ||||||
| Patella alta, n (%) | 28 (56%) | 8 (16%) | 22 (44%) | 19 (38%) | 17 (34%) | 13 (26%) |
| Patella baja, n (%) | 1 (2%) | 0 | 0 | 0 | 1 (2%) | 3 (6%) |
| Normal, n (%) | 21 (42%) | 42 (84%) | 28 (56%) | 31 (62%) | 32 (64%) | 34 (68%) |
NOTE. Shown are ISI, CDI, and BPI at 0°, 5°, 10°, and 15°.
BPI, Blackburne–Peel index; CDI, Caton–Deschamps index; ISI, Insall–Salvati index.
Normal ranges for each patellar height index. BPI: patella alta >1.06, patella baja <0.54; ISI: patella alta >1.2, patella baja <0.8; CDI: patella alta >1.3, patella baja <0.6.