Articular cartilage is the deformable tissue which covers the bone extremities of synovial joints. It appears to have two important functions:​

Firstly, it limits the stresses applied to the underlying or subchondral bone, due to its ability to deform, and secondly, cartilage provides the smooth articulating surfaces necessary for a joint to behave as an efficient bearing. The stiffness of cartilage will obviously influence the first of these two functions, and may well play a part in joint lubrication. Progressive softening of cartilage probably indicates early degenerative changes, which in time may lead to mechanical failure of the cartilage, and thence to osteoarthrosis.

Most published work concerning the mechanical properties of articular cartilage has dealt mainly with the patella, and most comparative studies have been performed between degenerate and visibly normal cartilage. Thus there is a lack of information in the published literature,concerning the mechanical properties of cartilage on surfaces other than the patella, and it has not been established whether a typical pattern of cartilage stiffness variation exists in the normal, healthy state.

The object of this investigation was initially to determine whether a pattern of stiffness variation exists for cartilage on the human femoral head. If a pattern was observed, then its relationship to other variables such as age, sex and the severity of localised degeneration, was to be determined. The relationship between the stiffness and chemical components of cartilage was to be investigated, as was the relationship between the stiffness and permeability to water.

Indentation tests were performed normal to the articular surface using two cylindrical indenters of the same diameter but with different end profiles;​ one being a plane end and the other a hemispherical end.

Sixteen femoral heads were subjected to detailed indentation surveys. Layered maps and histograms of the variation of both indentation and creep modulus, at two seconds after load application, were drawn for each femoral head.

The results revealed that a reproducible pattern of stiffness exists for cartilage on the femoral head. The stiffest cartilage is usually located in a band which extends over the superior aspect and around to the anterior and posterior facets. The softest cartilage is invariably located at or near to the margin of the fovea, and near to a localised area of degeneration.

An overall marked softening of the entire visually normal cartilage surface was observed in some femoral heads. This softening was progressive, and closely related to the severity of localised areas of degeneration, even though they were not tested. No significant dependence on age or sex was recorded.

A strong correlation was however recorded between the creep modulus and total mucopoly saccharide content of the tested areas. In addition a strong negative correlation was recorded between the creep modulus and permeability to water.

In the course of the investigation considerable attention was paid to experimental controls and associated experiments, in order to ensure maximum accuracy of the results.