Mri-based preliminary reference data and diagnostic discordance of patellar height indices in Vietnamese
Main Article Content
Abstract
A retrospective cross-sectional descriptive study of 130 knee MRI examinations at the University Medical Center Ho Chi Minh City (2019 - 2022) was conducted to describe preliminary reference data for four patellar height indices: Insall–Salvati (IS), modified Insall–Salvati (MIS), patellotrochlear index (PTI), and sagittal patellofemoral engagement (SPE), and to evaluated diagnostic discordance between bony-landmark indices (IS, MIS) and cartilaginous-landmark indices (PTI, SPE). Mean values were: IS = 1.12 ± 0.15; MIS = 1.74 ± 0.18; PTI = 0.43 ± 0.09; SPE = 0.49 ± 0.10. IS was significantly higher in females than males (1.18 vs 1.09; p = 0.0004). Within-group correlations were strong: PTI–SPE r = 0.87; IS–MIS r = 0.53 (both p < 0.001). Between-group correlations were non-significant (IS–PTI r = −0.08; IS–SPE r = −0.06). Discordance analysis showed that 44/130 cases (33.8%; 95% CI: 25.6–42.9%) exceeded IS > 1.2, yet none met the PTI < 0.18 threshold. These findings suggest a potential risk of overclassification of patella alta when applying the IS > 1.2 cut-off derived from foreign populations to Vietnamese patients.
Article Details
Keywords
Insall-Salvati index, patellotrochlear index, sagittal patellofemoral engagement, patellar height
References
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