Bone grafting in arthroscopy and sports medicine.

Bone graft substitutes include autografts, allografts, xenografts, and synthetics. Although autograft is still the gold standard, limited supply and donor morbidity must be considered. Allograft can vary in its bone-inductive qualities and may be processed into various shapes and constructs. Although allografts provide an osteoconductive matrix with some osteoinductivity, only limited anatomic constructs can be provided. Xenografts are abundant in supply, yet their shape and construct dimensions are restricted and xenograft properties are less than ideal due to the processing required to render the material nonimmunogenic. To achieve optimal bone graft properties, researchers are developing new materials with the goal of designing synthetics as close to autograft as possible. The advantages and disadvantages of all of these bone graft materials will be reviewed with emphasis on their relevance and applicability for sports medicine procedures.

Correlation of cartilage stiffness to thickness and level of degeneration using a handheld indentation probe.

The in vivo assessment of the quality of cartilage is a critical tool to determine how to clinically treat damaged cartilage. Utilizing nondestructive indentation, a hand-held instrument (ACTAEON Probe) was used to rapidly measure the stiffness of articular cartilage, which can then be correlated to cartilage condition. An integrated series of tests were performed to determine whether the Probe is sensitive enough to detect early degenerative changes in articular cartilage and to examine if it is dependent on the thickness of the cartilage being tested. Results demonstrated that there is no effect of thickness on the Probe measurements for clinically relevant human cartilage samples, that the Probe is sensitive enough to detect different levels of cartilage degeneration, and that Probe data correlate well with traditional creep indentation testing. This study demonstrates the utility of the Probe for detecting degenerative changes in animal and human joints.

Indentation testing of human cartilage: sensitivity to articular surface degeneration.

OBJECTIVE: To determine, for clinical indentation testing of human articular cartilage, the effects of aging and degeneration on indentation stiffness and traditional indices of cartilage degeneration; the relationship between indentation stiffness and indices of degeneration; and the sensitivity and specificity of indentation stiffness to cartilage degeneration. METHODS: Osteochondral cores from femoral condyles of cadaveric human donors were harvested. Samples were distributed into experimental groups based on donor age (young [20-39 years], middle [40-59 years], and old [>/=60 years]), and a macroscopic articular surface appearance that was either normal or mildly degenerate, without deep erosion. Samples were analyzed for indentation stiffness, cartilage thickness, India ink staining (quantitated as the reflected light score), and Mankin-Shapiro histopathology score. RESULTS: Indentation stiffness, India ink staining, and the histopathology score each varied markedly between normal-sample and degenerate-sample groups but varied relatively little between normal samples obtained from different age groups. A decrease in indentation stiffness (softening) correlated with a decrease in the reflectance score and an increase in the overall histopathology score, especially the surface irregularity component of the histopathology score. Receiver operating characteristic analysis suggested that the indentation testing could accurately detect cartilage degeneration as indicated by macroscopic appearance, India ink staining, and histopathology score. CONCLUSION: The indentation stiffness of the normal to mildly degenerate samples tested in this study was sensitive to mild degeneration at the articular surface and was insensitive to changes associated with normal aging or to slight variations in cartilage thickness. This suggests that indentation testing may be a useful clinical tool for the evaluation of early-stage degenerative changes in articular cartilage.