ArticleOrthopaedic surgery2025
A Comparative CT Study on Anatomical Characteristics of Pediatric Habitual Patellar Dislocation in Extension and Flexion.
Article in Orthopaedic surgery, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
2 citing papers in PubMed.
- Postoperative remodeling and developmental improvement of femoral trochlear dysplasia in pediatric habitual patellar dislocation.Frontiers in pediatrics · 2026Article
- A Comparative CT Study on Anatomical Characteristics of Pediatric Habitual Patellar Dislocation in Extension and Flexion.Orthopaedic surgery · 2025Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
Abstract
objectiveHabitual patellar dislocation (HDP) in children and adolescents is divided into dislocation in flexion and dislocation in extension, but their pathogenesis remains unclear. Our purpose is to focus on investigating the anatomical difference between the extended dislocation and the flexed dislocation of HDP.
methodsWe retrospectively observed all patients diagnosed as HDP who underwent surgery at our institution from May 2016 to August 2023. Patients were categorized into two subgroups according to "J sign": the extension group and the flexion group. We measured and compared the various anatomical parameters on CT images, including patellar dysplasia, trochlear dysplasia, alignment of the patellofemoral joint, and torsional deformity of the knee joint. Continuous data were analyzed using the t-test, while categorical data were analyzed using Fisher exact test and Mann-Whitney U test.
resultsWe enrolled 20 patients (average age of 9 years old, ranging from 6 to 15; 14 patients in the extension group and 6 patients in the flexion group) with 30 knees. The extension group exhibited significantly greater Wiberg index (0.62 ± 0.09 vs. 0.56 ± 0.05, p = 0.030), lateral patellar angle (17.83 ± 4.5 vs. 12.24 ± 5.7, p = 0.009), PT/FT ratio (1.45 ± 0.1 vs. 1.31 ± 0.1, p = 0.005), and Caton-Deschamps index (1.46 ± 0.3 vs. 1.17 ± 0.1, p = 0.015) than those in the flexion group. Meanwhile, the flexion group demonstrated greater patellar lateralization distance (24.03 ± 11.5 vs. 16.26 ± 7.3, p = 0.036), patellar inclination angle (50.75 ± 13.1 vs. 29.98 ± 14.5, p = 0.001), lateral patellofemoral angle (38.49 ± 13.5 vs. 18.32 ± 8.2, p = 0.000) and congruence angle (57.57 ± 23.3 vs. 28.15 ± 16.7, p = 0.001) when knees were extending but a smaller lateral trochlear inclination angle (18.84 ± 6.9 vs. 12.49 ± 5.2, p = 0.026) than those in the extension group. Additionally, the knees in the flexion group predominated the femoral trochlea of Dejour type C and D (100%) while only half of the extension group had Dejour type C and D (51%). The duration of symptoms before surgery was significantly longer in the extension group compared to the flexion group (25.93 ± 25.8 months vs. 9.33 ± 4.18 months, p = 0.034). Parameters related to torsional abnormality of the lower extremity showed no significant difference between the two groups.
conclusionsPatients with HDP in extension had patella alta, more severe patellar dysplasia, while those with HDP in flexion had a more inclined patella, laterally positioned patella when knees extended, and a more dysplastic femoral trochlea. These differences provide reasonable references for doctors to better understand the mechanisms of dislocation and the design of optimal surgical strategies. CLINICAL RELEVANCE: Improved understanding of anatomical features of HDP is critical to informing clinical treatment decisions.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.