No abstract

Background: Multi-planar proximal tibial slopes may be associated with increased likelihood of osteoarthritis and anterior cruciate ligament injury, due in part to their role in checking the anterior-posterior stability of the knee. Established methods suffer repeatability limitations and lack computational efficiency for intuitive clinical adoption. The aims of this study were to develop a novel automated approach and to compare the repeatability and computational efficiency of the approach against previously established methods. Methods: Tibial slope geometries were obtained via MRI and measured using an automated Matlab-based approach. Data were compared for repeatability and evaluated for computational efficiency. Results: Mean lateral tibial slope (LTS) for females (7.2°) was greater than for males (1.66°). Mean LTS in the lateral concavity zone was greater for females (7.8° for females, 4.2° for males). Mean medial tibial slope (MTS) for females was greater (9.3° vs. 4.6°). Along the medial concavity zone, female subjects demonstrated greater MTS. Conclusion: The automated method was more repeatable and computationally efficient than previously identified methods and may aid in the clinical assessment of knee injury risk, inform surgical planning, and implant design efforts.

Background The proximal tibia is a geometrically complex, asymmetrical, and variable structure, is heavily implicated in arthrokinematics of the knee joint, and thus impacts weight-bearing knee biomechanics. Such variability and asymmetry may be implicated in knee pathologies such as non-contact anterior cruciate ligament injury. Medial, lateral, and coronal tibial slopes have been identified as anatomic parameters that may increase predisposition to knee injuries, but the extent to which each contributes has yet to be fully realized. Previously, two-dimensional methods have quantified tibial slopes, but more reliable 3D methods may prove advantageous. Aims The aims were: (1) to explore the reliability of two-dimensional methods, (2) to propose a novel three-dimensional measurement approach, and (3) to compare the data derived from traditional and novel methods. Methods Medial, lateral, and coronal tibial slope geometry from both knees (left and right) of one subject were obtained via magnetic resonance images and measured by four trained observers from two-dimensional views. The process was repeated via three-dimensional approaches and data were evaluated for intra- and inter- rater reliability. Results The conventional method presented a weaker Intraclass Correlation Coefficient (ICC) for the measured slopes (ranging from 0.43 to 0.81) while the resultant ICC for the proposed method indicated greater reliability (ranging from 0.84 to 0.97). Statistical analysis supported the novel three-dimensional approach for production of more reliable and repeatable results for each of the slopes calculated. Conclusions The novel three-dimensional method for calculating tibial plateau slope may be more reliable than previously established methods and may provide an important tool during assessment of knee injury risk, susceptibility to osteoarthritis, as part of anterior cruciate ligament injury risk assessment, and in design of total knee implants.

Computational modeling with finite element analysis (FEA) is an integral component of medical device design and development. Researchers assess dimensions and stability of the experimental device; test load sharing, stresses, and strains; and analyze failures and modifications. The most important step in FEA is validation of the model. Testing should include decompression and stabilization procedures simulated in the finite element model (FEM). Prerequisites of quality FEA include a solid understanding of morphology and material properties of the model, a firm grasp of the effects of loads on body structures, and the work of a skilled bioengineer who can translate the ideas of surgeons into an appropriate FEM. With today's modern techniques-computed tomography/magnetic resonance imaging, etc.-the bioengineer moves from scan to FEM in just weeks.