MRI criteria for patella alta and baja
Patellar length (PL) and patellar tendon length (TL) were measured .....on sagittal images by a line connecting the superior and inferior patellar poles and the shortest length of the inner margin of the tendon respectively. TL/PL ratio was subsequently calculated
Ratios defined for patella alta and baja were 1.52 and 0.79 respectively in females and 1.32 and 0.74 respectively in males
Skeletal Radiol. 2004 Aug;33(8):445-50. Epub 2004 Jun 24.
http://www.ncbi.nlm.nih.gov/pubmed/15221214
Factors predisposing to Patella Instability:
1. Trochlea dysplasia
2. Patella alta (TL/PL > 1.3 abnormal)
3. Lateralisation of tibial tuberosity
MR Imaging of Patellar Instability: Injury Patterns and Assessment of Risk Factors
http://radiographics.rsna.org/content/30/4/961.full
Factors predisposing to Patella Instability:
1. Trochlea dysplasia
2. Patella alta (TL/PL > 1.3 abnormal)
3. Lateralisation of tibial tuberosity
MR Imaging of Patellar Instability: Injury Patterns and Assessment of Risk Factors
http://radiographics.rsna.org/content/30/4/961.full
2 comments:
My MRI findings were lateral patellar tilt with chondral fissuring within the patellar apex and lateral petellar facet as intermediate grade chondomalcia patella. also marrow edema within the posterior tibial plateau as chronic deenerative fibrovascular reaction. I am confused because my Dr has explained that the patellar tilt is subluxation but some articles say the two diagnosis' are different. Is patellar tilt the same as subluxation, given my findings?
Strictly speaking subluxation means a partial or minor dislocation and tilt means to slope or angle off centre.
The bottom line though is that the patella, whether subluxed, tilted or both, is not optimally positioned with respect to the trochlea of the femur and this would predispose one to chondromalacia patella.
Usually this would manifest as anterior knee pain if it is the sole finding.
Hope this helps.
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