Elsevier

Osteoarthritis and Cartilage

Volume 5, Issue 6, November 1997, Pages 377-386
Osteoarthritis and Cartilage

Original article
Differences in patellofemoral joint cartilage material properties and their significance to the etiology of cartilage surface fibrillation*

https://doi.org/10.1016/S1063-4584(97)80042-8Get rights and content
Under a Creative Commons license
open archive

Summary

Objective

To determine if differences in biomechanical properties and biochemical composition exist between human patellar articular cartilage and the opposing femoral articular cartilage.

Design

The biomechanical properties and biochemical composition of the articular cartilage of 17 knees from 13 donors were determined for four sites on the patella and three sites on the femur represting regions of contact at 30° and 90° of flexion. The material properties were determined by biphasic indentation testing, yielding the compressive aggregate modulus, HA, permeability, k, and Poisson's ratio, vs. The thickness of the cartilage at the indentation site, h, was also measured using a needle probe. Full-thickness samples of cartilage adjacent to each indentation site were used for wet weight, sulfated glycosaminoglycan content and hydroxyproline content determinations.

Results

The patellar cartilage was found to have a lower compressive aggregate modulus by 30% (P<0.001), higher premeability to fluid flow by 66% (P<0.001) and greater thickness by 23% (P=0.017) than that of the opposing femoral cartilage. The Poisson's ratios for both surfaces were found to be nearly zero. The water content of the patella was higher by 5% (P=0.031) and the proteoglycan content lower by 19% (P=0.030) than that of the femur. However, no differences were found between the collagen contents of the cartilages.

Conclusions

Significant differences were found between the intrinsic material properties of the patellar cartilage and those of the femoral-trochlear cartilage. This variability of cartilage material properties with the patellofemoral joint may help explain why patellar cartilage has been frequently observed clinically to exhibit earlier and more severe fibrillation changes than the opposing femoral cartilage.

Key words

Articular cartilage
Biomechanics
Material properties
Patellofemoral joint

Cited by (0)

*

Partial support for this study was provided by a Bristol-Myers Squibb Center of Excellence Grant for Orthopaedic Research to the New York Orthopaedic Hospital Research Laboratory, Columbia University.

Present address: Department of Orthopaedic Surgery, The Mount Sinai Medical Center, Cleveland, OH 44106-4198, U.S.A.