Limite patológico da distância tendão patelar-sulco da tróclea utilizando imagens de ressonância magnética em pacientes com instabilidade patelar

Resumo

Objetivo

Avaliar e comparar a distância tendão patelar-sulco troclear (TP-ST) em indivíduos com e sem instabilidade patelar. Um segundo objetivo foi definir um limiar patológico de TP-ST por meio de ressonância magnética (RM) nuclear em pacientes com instabilidade patelar.

Métodos

A distância TP-ST de 52 joelhos foi medida em 48 indivíduos com instabilidade patelar objetiva (grupo instabilidade) por RM. Essas medidas foram comparadas àquelas feitas em 50 joelhos de 44 indivíduos sem histórico de instabilidade patelar (grupo controle).

Resultados

A distância TP-ST no grupo instabilidade (20,6 ± 5,0 mm) foi maior do que no grupo controle (11,8 ± 3,4 mm; p < 0,001). O valor de 15,5 mm foi determinado como limiar patológico, com acurácia de 81,4%, em exames de RM.

Conclusão

Indivíduos com instabilidade patelar apresentam medidas estatisticamente maiores de TP-ST em comparação a pacientes sem instabilidade. Portanto, valores de TP-ST superiores a 15,5 mm à RM representam uma força de lateralização patológica do mecanismo extensor relacionada à instabilidade patelar.

Abstract

Objective

To evaluate and compare the values of the patellar tendon-trochlear groove (PT-TG) distance in individuals with and without patellar instability. Additionally, we aimed to define a cut-off value for the pathological limit of the PT-TG through nuclear magnetic resonance imaging (MRI) in patients with patellar instability.

Methods

The PT-TG distance of 52 knees was measured in 48 individuals with objective patellar instability (instability group) by MRI. These measurements were compared with those made in 50 knees of 44 individuals without a history of patellar instability (control group).

Results

The PT-TG distance in the instability group (20.6 ± 5.0 mm) was greater than in the control group (11.8 ± 3.4 mm; p < 0.001). A value of 15.5 mm was determined as the pathological limit, with an accuracy of 81.4%, in MRI exams.

Conclusion

Individuals with patellar instability have statistically higher measurements of PT-TG when compared with patients without it. Therefore, values higher than 15.5 mm for PT–TG seen in MRI exams represent a pathological lateralization force of the extensor mechanism related to patellar instability.

Palavras-chave

articulação patelofemoral - imagem por ressonância magnética - instabilidade articular - joelho - ligamento patelar

Keywords

joint instability - knee - magnetic resonance imaging - patellar ligament - patellofemoral joint

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