Recurrent dislocation of the patella. Histochemical and electromyographic evidence of primary muscle pathology

Abstract

The role of muscle function in the aetiology of recurrent dislocation of the patella has been examined. Eleven of the 12 patients we studied had joint hypermobility. Muscle biopsies from eight of nine patients treated by surgery had a predominance of abnormal Type 2C fibres, and three of six patients whose quadriceps muscles were studied by electromyography also had abnormal results. Our preliminary findings suggest that there may be a primary muscular defect in many cases of recurrent dislocation of the patella.

Surgical Management of Shoulder and Knee Instability in Patients with Ehlers-Danlos Syndrome: Joint Hypermobility Syndrome

“…Knee instability (any type) in hEDS may be partially explained by substantial muscle weakness in the quadriceps and hamstrings, and it is hypothesized that 1 cause of hEDS muscle weakness is related to defective collagen function, leading to abnormal muscle extracellular matrix composition. 26 27 28) This may influence muscle function by reducing force generated and transmitted through tendons. Other contributors to muscle weakness may include chronic pain and increased fatigue.…”

Habitual dislocation of the patella

“…Floyd et al reported that muscle biopsies from eight out of nine cases of recurrent dislocation showed abnormal Type 2C fibres and electromyography of the quadriceps was abnormal in three out of six cases tested [2]. They pointed out that none of the features previously identified as possible causes of recurrent dislocation such as genu valgum, an increased Q angle, lateral placement of the tibial tuberosity, and a low lateral femoral condyle, were present in every case and these did not explain the prevalence of the condition in girls in their late teens.…”

“…T h e p u r p o s e o f this p a p e r is to describe a case o f habitual dislocation o f the patella a n d to correlate the aetiology with the o b s e r v a t i o n s put forw a r d b y F l o y d et al [2] a n d with the a u t h o r ' s previous experience.…”

Luxación recurrente de patela

“…En términos generales, la reluxación se da por un trauma de alta intensidad sobre las estructuras de la rodilla, 5 en las que su proceso de reparación fue deficiente impidiendo que cumpla la función de soporte que antes tenía; la mayoría de rodillas con reluxación presentan alteraciones previas (morfológicas, angulares, rotacionales, de potencia muscular o de elasticidad) que predisponen para que un trauma de intensidad menor haga que las estructuras que lograban mantener unas relaciones articulares Luxación recurrente de patela sobre la permanente ubicación dinámica de la patela con respecto al fémur. 1,18 Factores de riesgo Las luxaciones de patela están influenciadas por varios factores que afectan la estabilidad de la articulación de una u otra forma. Entre éstos se encuentran: 1) Edad: la literatura muestra una frecuencia mayor en jóvenes, [19][20][21] pero algunos autores tienen opinión contraria.…”