Motion at the knee joint is a complex mechanical phenomenon. Stability is provided by a combination of static and dynamic structures that work in concert to prevent excessive movement or instability that is inherent in various knee injuries. The anterior cruciate ligament (ACL) is a main stabilizer of the knee, providing both translational and rotatory constraint. Despite the high volume of research directed at native ACL function, pathogenesis and surgical reconstruction of this structure, a gold standard for objective quantification of injury and subsequent repair, has not been demonstrated. Furthermore, recent studies have suggested that novel anatomic structures may play a significant role in knee stability. The use of biomechanical principles and testing techniques provides essential objective/quantitative information on the function of bone, ligaments, joint capsule, and other contributing soft tissues in response to various loading conditions. This review discusses the principles of biomechanics in relation to knee stability, with a focus on the objective quantification of knee stability, the individual contributions of specific knee structures to stability, and the most recent technological advances in the biomechanical evaluation of the knee joint.
Based on the non-uniform geometry of the patella, an emphasis should be made on harvesting a standard percentage of patella thickness rather than a fixed depth. In order to minimize the incidence of a patellar fracture, bone blocks should not be taken laterally and should not exceed 30 % of the total patella thickness at the harvest site.
Background:
The objective of this study was to determine the feasibility of assessing tendon quality as quantified by histology through changes in quantitative ultrasound measures.
Methods:
Eight cadaveric shoulders (four with a small supraspinatus tendon tear) were examined using conventional B-mode ultrasound in the transverse plane by internally rotating and hyperextending the humerus. Quantitative ultrasound measures (skewness, kurtosis, variance, and echogenicity) were calculated based on the grayscale distribution of the ultrasound image taken of the supraspinatus tendon near the insertion site. The specimens were then dissected to the supraspinatus tendon where tendon biopsies were taken near the insertion site, mid-substance, and myotendinous junction. Through histology, tendon quality was evaluated based on collagen fiber organization, fatty infiltration, nuclei shape, and cellularity. Correlations between quantitative ultrasound measures and histological grades of tendon quality were determined through Pearson or Spearman's rho correlations.
Results:
A total of three significant correlations between quantitative ultrasound measures and histological parameters of tendon quality were found. Significant correlations between kurtosis and cellularity at the insertion site (
r
= 0.724) (
P
< 0.05) as well as variance and fatty infiltration at the myotendinous junction (ρ = −0.843) (
P
< 0.05) and for the whole tendon (ρ = −0.826) (
P
< 0.05) were found.
Conclusion:
The results show the potential for quantitative ultrasound measures to assess factors of tendon quality that can only be determined through histology. With further development of the methodology that utilizes quantitative ultrasound measures, clinicians might be able to evaluate the tendon quality noninvasively in future.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.