Patella alta
Patella alta, or a high riding patella, describes a situation where the position of the patella is considered high. It may be idiopathic or may result secondary to a patellar tendon rupture.
Epidemiology
Associations
Several conditions are known to be associated with patella alta, including:
- idiopathic retropatellar pain 5
- recurrent dislocation of the patella 2
- chondromalacia patellae 2
- knee joint effusion 2
Patella alta may also occur as a result of spastic cerebral palsy 6.
Radiographic features
On sagittal images, it is usually considered when the Insall-Salvati ratio is greater than 1.3-1.5 1-3.
On radiography, it is important that standard positioning is used, with the knee flexed at 30 degrees. An off-angle x-ray beam or non-standard positioning may result in a spuriously abnormal ratio.
Related Radiopaedia articles
Knee pathology
The knee is a complex synovial joint that can be affected by a range of pathologies:
- bone and cartilage
-
knee fractures
- distal femoral condyle fracture
- tibial plateau fracture (classification)
- patella fracture
-
avulsion fractures of the knee
- arcuate complex avulsion fracture (arcuate sign)
- anterior cruciate ligament avulsion fracture
- biceps femoris avulsion fracture
- iliotibial band avulsion fracture
- patella fracture
- posterior cruciate ligament avulsion fracture
- reverse Segond fracture
- Segond fracture
- semimembranosus tendon avulsion fracture
- Stieda fracturechronic avulsion injuries
- dislocation
- chondromalacia patellae
- osteoarthritis of the knee
- osteochondral defects
- osteochondritis dissecans of the knee
- patterns of bone bruise in knee injury
-
knee fractures
- ligaments
- anterior cruciate ligament tear
- anterior cruciate ligament ganglion cyst
- anterior cruciate ligament mucoid degeneration
- posterior cruciate ligament tear
- medial collateral ligament tear
- lateral collateral ligament tear
- medial patellofemoral ligament tear
- posterolateral corner injury
- posteromedial corner injury
- tendons
- meniscal lesions
- bursosynovial lesions
- fat pad
- popliteal fossa
- fascia
- alignment
- knee
- patellofemoral
- gamut
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