Embryology of the acetabular labral-chondral complex

Abstract

Damage to and repair of the acetabular labral-chondral complex are areas of clinical interest in the treatment of young adults with pain in the hip and in the prevention of degenerative arthritis of the hip. There are varying theories as to why most acetabular tears are located anterosuperiorly. We have studied the prenatal development of the human acetabular labral-chondral complex in 11 fetal hips, aged from eight weeks of gestation to term. There were consistent differences between the anterior and posterior acetabular labral-chondral complex throughout all ages of gestation. The anterior labrum had a somewhat marginal attachment to the acetabular cartilage with an intra-articular projection. The posterior labrum was attached and continuous with the acetabular cartilage. Anteriorly, the labral-chondral transition zone was sharp and abrupt, but posteriorly it was gradual and interdigitated. The collagen fibres of the anterior labrum were arranged parallel to the labral-chondral junction, but at the posterior labrum they were aligned perpendicular to the junction. We believe that in the anterior labrum the marginal attachment and the orientation of the collagen fibres parallel to the labral-chondral junction may render it more prone to damage than the posterior labrum in which the collagen fibres are anchored in the acetabular cartilage. The anterior intra-articular projection of the labrum should not be considered to be a pathological feature.

The role of the acetabular labrum in hip dysplasia

“…The posterior region is directly attached to and continuous with the articular cartilage, and here the fibers are organized perpendicular to the margin. This histological difference may in part explain why most tears of the labrum are located anteriorly (Cashin et al 2008). …”

Brief communication: Developmental dysplasia of the hip in medieval London

“…1). The following soft-tissue and skeletal changes in DDH have also been reported in the clinical literature: acetabular labral tears (Fujii et al, 2009;Noguchi et al, 1999;Tanzer and Noiseux, 2004;Cashin et al, 2008;Tschauner and Hofman, 1998), degenerative changes to the acetabular rim (Ganz and Leunig, 2007;McCarthy and Lee, 2002;Fujii et al, 2009), abnormal femoral head and neck morphology and differences in limb length (Storer and Skaggs, 2006), valgus angulation at the knee (Kandemir et al, 2002), and osteoarthritis (OA) (Jacobsen et al, 2005;McCarthy and Lee, 2002;Haene et al, 2007;Jessel et al, 2009). Even if dysplasia and subluxation present as a unilateral condition, the contralateral hip joint will also be abnormal compared with a normal healthy hip, in terms of femoral neck anteversion, femoral neck-shaft angle, and increased acetabular anteversion (Jacobsen et al, 2006).…”

Inverted Acetabular Labrum

“…[10] demonstrated that the anterior acetabular cartilage was covered by a hat-shaped anterior margin of the labrum cartilage complex, while the intra-articular projection of the labrum into the joint resulted in the formation of a crypt between the acetabular cartilage surface and the labrum. However, the posterior labrum was directly attached to the acetabular cartilage in the absence of an intra-articular projection.…”