Patellar position in patients with patellofemoral syndrome as characterized by anatomo-radiographic study

Abstract

ObjectivesTo determine the prevalence of high patella in adult patients with knee pain, and to correlate patellar height with symptoms of patellar instability, episode of patellofemoral dislocation and anterior pain in the knee; and also verify the concordance correlation between the Insall-Salvati and Caton-Deschamps indices.MethodCross-sectional study analyzing the medical records of patients with knee pain, using lateral view knee radiographs with 30° degrees of flexion and computed tomography. The values of the Insall-Salvati index and the Caton-Deschamps index were used to determine the patellar height.ResultsA total of 756 records were analyzed, resulting in 140 knees studied, 39% men and 61% women. Both indices produced statistically significant associations for the occurrence of high patella and signs of instability and episodes of dislocation, but there was no significant association for anterior knee pain. The Kappa index obtained when analyzing the concordance correlation between the Insall-Salvati index and Caton-Deschamps index points to a regular association between them.ConclusionPatients with high patella present a higher prevalence of instability. Having a high patella has no significant relationship with the presence of anterior knee pain. The Insall-Salvati and Caton-Deschamps indices demonstrate a regular agreement on the presentation of patellar heights results.

Anatomo-radyographic study in individuals with and without medial patellofemoral ligament rupture

“…In a study, a total of 756 records were analyzed, resulting in 140 knees studied, 39% men and 61% women. They found insal salvati index produced statistically signi cant associations for the occurrence of high patella and signs of instability and episodes of dislocation, but there was no signi cant association for anterior knee pain [23]. According to study of Raja et al, mean insall-salvati index was 1.03 ± 0.11 in test group and 1.07 ± 0.16 in control groups with no statistical difference.…”

Atualização em instabilidade patelar

“…3,17 Fatores de risco anatômicos e estruturais para instabilidade patelar foram identificados, tais como: patela alta, morfologia patelar anormal, displasia troclear, hipermobilidade patelar, variações da anatomia do LPFM, hiperfrouxidão ligamentar generalizada, hipoplasia do vasto medial oblíquo, aumento do ângulo Q, aumento da anteversão femoral, alinhamento em valgo e rotação tibial externa. 7,8,20 Dejour et al, 21 em 1994, consideraram quatro fatores predisponentes à luxação: 1) displasia da tróclea; 2) inclinação lateral da patela, interpretada como displasia do vasto medial oblíquo; 3) patela alta e 4) lateralização da tuberosidade anterior da tíbia (TAT) (aumento do ângulo Q). Um estudo observacional prospectivo analisou a morfologia patelofemoral nas crianças esqueleticamente imaturas com e sem luxação primária da patela, e encontraram diferenças significativas nas medidas relacionadas à displasia troclear como maior ângulo do sulco e menor profundidade troclear (< 3 mm), que resultam em aumento da altura condilar central.…”

“…3,17 Anatomical and structural risk factors for patellar instability were identified, such as: high patella, abnormal patellar morphology, trochlear dysplasia, patellar hypermobility, variations in the anatomy of the MPFL, generalized ligament hyperlaxity, hypoplasia of the oblique medial vastus, increased Q-angle, increased femoral anteversion, valgus alignment, and external tibial rotation. 7,8,20 Dejour et al, 21 in 1994, considered four factors predisposing to dislocation: 1) trochlear dysplasia; 2) lateral inclination of the patella, interpreted as dysplasia of the vastus oblique medial; 3) high patella and 4) lateralization of the anterior tuberosity of the tibia (ATT) (increased Q angle). A prospective observational study analyzed the patellofemoral morphology in skeletally immature children with and without primary patellar dislocation and found significant differences in measurements related to trochlear dysplasia such as greater groove angle and lower trochlear depth (< 3 mm), which result in increased central condylar height.…”

“…2,5 A instabilidade da articulação patelofemoral é multifatorial, a presença de fatores predisponentes como a anteversão femoral, torção tibial externa, torção femoral interna, geno valgo, displasia patelar, displasia troclear, patela alta, atrofia do vasto medial oblíquo, pé plano e hiperfrouxidão generalizada, podem influenciar a ocorrência de luxações recorrentes. 6,7 As luxações patelares são principalmente laterais e o principal mecanismo de lesão durante a atividade física é a rotação interna do fêmur com o pé plantado, componente valgo e um deslocamento lateral súbito da patela, ou um impacto direto que desloca a patela da articulação. Contudo, também podem ocorrer após traumas de baixa energia em pessoas com fatores predisponentes.…”

“…2,5 Patellofemoral joint instability is multifactorial, the presence of predisposing factors such as femoral anteversion, external tibial torsion, internal femoral torsion, geno valgus, patellar dysplasia, trochlear dysplasia, high patella, oblique medial vastus atrophy, flat foot, and generalized hyperlaxity may influence the occurrence of recurrent dislocations. 6,7 Patellar dislocations are mainly lateral, and the main mechanism of injury during physical activity is the internal rotation of the femur with the foot planted, valgus component and a sudden lateral displacement of the patella, or a direct impact that displaces the patella from the joint. However, they can also occur after low-energy trauma in people with predisposing factors.…”