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Morphology and Anatomic Patellar Instability Risk Factors in First-Time Traumatic Lateral Patellar Dislocations: A Prospective Magnetic Resonance Imaging Study in Skeletally Immature Children.
- Source :
-
The American journal of sports medicine [Am J Sports Med] 2017 Jan; Vol. 45 (1), pp. 50-58. Date of Electronic Publication: 2016 Oct 01. - Publication Year :
- 2017
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Abstract
- Background: The incidence of primary lateral patellar dislocation (LPD) in children aged 9 to 14 years is 0.6 to 1.2 per 1000. Causation is assumed to be multifactorial, including anatomic variants of the patellofemoral (PF) joint that result in a higher risk of LPD. No publication has compared the morphology of the PF joint and anatomic patellar instability risk factors (APIFs) in a primary LPD population versus controls, defining children by skeletal maturity.<br />Purpose: To characterize the PF morphology and APIFs (trochlear dysplasia, abnormal lateral patellar tilt, elevated tibial tubercle-trochlear groove [TT-TG] distance, patella alta) through magnetic resonance imaging (MRI) measurements in skeletally immature children with and without a primary LPD and to identify (potential) distinctive differences between these 2 groups.<br />Study Design: Cross-sectional study; Level of evidence, 3.<br />Methods: A prospective series of 103 skeletally immature children aged 9 to 14 years with an MRI-confirmed primary LPD were matched with a control group of 69 children. The PF morphology and APIFs were assessed during a 2.5-year period with standardized MRI using sagittal and axial views.<br />Results: In the LPD group, 79% had 2 to 4 APIFs compared with 7% in the control group. All major measurements of trochlear dysplasia were significantly different between the 2 groups. The mean central condylar height was significantly higher in the LPD group compared with the control group, resulting in a lower trochlear depth (2.3 vs 4.5 mm, respectively) and higher sulcus angle (156.7° vs 141.1°, respectively). The LPD group had significantly higher values of patellar height, Caton-Deschamps index (1.33 vs 1.15, respectively), lateral patellar tilt (21.1° vs 8.5°, respectively), and TT-TG distance (13.9 vs 9.8 mm, respectively) compared with the control group. The main divergent APIF was trochlear dysplasia (defined as trochlear depth <3 mm), seen in 74% of the LPD group compared with 4% of the control group. Elevated TT-TG distance as a single APIF was never present in the LPD group; patellar tilt was only seen in the LPD group. The most common APIF in the control group was patella alta (36%).<br />Conclusion: There was a significant difference in mean values of all established APIFs between the children with a first-time LPD and the controls. Trochlear dysplasia was the main APIF, and together with lateral patellar tilt (≥20°), they had the strongest association with LPD.
- Subjects :
- Adolescent
Child
Cross-Sectional Studies
Female
Humans
Joint Instability diagnostic imaging
Magnetic Resonance Imaging
Male
Patellar Dislocation diagnostic imaging
Patellofemoral Joint anatomy & histology
Patellofemoral Joint diagnostic imaging
Prospective Studies
Risk Factors
Sweden
Joint Instability pathology
Patellar Dislocation pathology
Patellofemoral Joint pathology
Subjects
Details
- Language :
- English
- ISSN :
- 1552-3365
- Volume :
- 45
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- The American journal of sports medicine
- Publication Type :
- Academic Journal
- Accession number :
- 27613760
- Full Text :
- https://doi.org/10.1177/0363546516663498