Patellofemoral instability is related to anatomy. Magnetic resonance imaging (MRI) provides anatomic detail, but spoiled gradient echo (SPGR) imaging during isometric quadriceps contraction provides objective functional data for diagnosing patellofemoral laxity. Knee MRI studies and medical charts of 398 patients were retrospectively reviewed. Two independent blinded observers evaluated the knee MRI studies for patellofemoral morphology and patellar position on axial SPGR images during relaxation and isometric quadriceps contraction for lateral patellar migration. Charts were reviewed for history of patellofemoral instability or dislocation. Patients were divided into 2 groups: group 1 comprised patients with 2.5 mm or more of lateral patellar migration on axial SPGR images, and group 2 comprised patients with less than 2.5 mm of patellar subluxation. Logistic regression models were used to determine relationships between patellofemoral subluxation of 2.5 mm or more and (1) history of dislocation or clinical patellofemoral instability, (2) grade 4 chondromalacia on MRI, (3) corrected central trochlear height, and (4) differential trochlear height (corrected for lateral condylar height). Statistically significant associations were found between patellar subluxation and each of the above 4 clinical/morphologic measures. Lateral patellar migration of 2.5 mm or more on SPGR obtained during quadriceps contraction had statistically significant associations with the above 4 measures. Evaluation of SPGR of quadriceps contraction provides objective functional information about patellofemoral instability for management decisions.

Download full-text PDF

Source
http://dx.doi.org/10.3928/01477447-20121217-12DOI Listing

Publication Analysis

Top Keywords

patellofemoral instability
16
quadriceps contraction
16
lateral patellar
12
patellar migration
12
functional data
8
patellofemoral
8
patellofemoral laxity
8
isometric quadriceps
8
contraction objective
8
objective functional
8

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!