Patients with patella alta may experience less severe cartilage damage after instability
Key takeaways:
- Patients with patella alta have less severe cartilage damage after patellar instability.
- Patients with patella alta had a lower frequency of full-thickness defects compared with patients with patella norma.
Compared with patients with normal patellar height, patients with patella alta demonstrated less severe cartilage damage and a lower frequency of full-thickness defects after patellar instability, according to published results.
To assess severity and location of cartilage damage among patients with patellar instability who underwent patellar realignment surgery, researchers at the Rothman Orthopaedic Institute analyzed MRIs of 50 patients with patella alta and 71 patients with patella norma. Researchers used the area measurement and depth and underlying structures (AMADEUS) score to determine cartilage defect severity, with a higher AMADEUS score indicating superior articular cartilage status.
Overall, 68% of the patella alta group (n = 34) and 62% of the patella norma group (n = 44) showed cartilage defects on MRI. Researchers noted no differences in defect size or location between the groups. According to the study, chondral injuries were most common in the medial patellar facet, the lateral facet and lateral femoral condyle.
Researchers found 60% of patients in the patella alta group and 82% of patients in the patella norma group had full-thickness defects. Additionally, overall AMADEUS score was 68.9 in the patella alta group and 62.1 of patients in the patella norma group.
Researchers concluded that patients with patella alta experience less severe cartilage damage after patellofemoral instability events, despite a similar frequency of sustained cartilage defects to patients with patella norma.
“Patients with patella alta may have dislocation when the patella is less engaged in the trochlea, as a result of altered biomechanics,” the researchers wrote in the study. “Thus, this may lead to less bone-to-bone and cartilage-to-cartilage shear forces occurring as well,” they suggested.
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