Structural Anatomy
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/21669
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Browsing Structural Anatomy by Author "Kosmopoulos, Victor"
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Item Establishing Experimental Sample Uniformity Prior to Patella Component Fixation Testing(2018-03-14) Wagner, Russell; Kosmopoulos, Victor; Beck, Cameron; Hogsett, Cameron; Nestlerode, Christina; Nwannunu, BrianPurpose: It is imperative to perform quality control studies to validate experimental sample quality prior to testing. Due to the inherent inconsistency when using cadaveric bone as a means to test clinically relevant hypotheses, one such quality check is to geometrically study the variability present in the bone samples. Thus, as a quality control step prior to investing resources to undertake the overall aim of studying patella component fixation in total knee arthroplasty (TKA), this study aims to establish sample uniformity by analyzing patella length, width, and depth. Methods: Ten random pairs of patellae were harvested from a possible 39 embalmed cadavers. Each patella was then prepared by an orthopaedic surgeon, as if performing an intraoperative TKA, for fixation of a patella implant component. After preparation but before adding a patellar component and cement, the surgeon visually inspected each patella and separated each pair with the better bone quality sample as part of the control group and the other as part of the treatment group. Measurements were then taken by two independent observers using a caliper to determine the superior-inferior patellar length (SIL), medial-lateral width (MLW), and the sectioned patellar thickness (TH). T-tests were performed to establish interobserver measurement reliability and the geometric uniformity between the control and treatment groups and between the left and right samples. Results: There was no significant difference between readers in the SIL (p=0.48), MLW (p=0.58) and TH (p=0.23) measurements. No significant differences were found when comparing between the control and experimental groups for any of the three measures (SIL p=0.21, MLW p=0.44, TH p=0.90). There was however, a significant difference observed in the sectioned preparation TH (p=0.007) when comparing left and right knee patellae. Conclusions: Based on the geometric outcomes measured (SIL, MLW, TH) the results of this study validate the sample uniformity when comparing patellae based on control and treatment groups rather than right verses left. Doing so helps control sample quality for completing the overall aim to study cement fixation methods of the patellar component in TKA.Item Validating the Pig ACL as a Model for Pre-Clinical Testing of Ligament Repair Techniques(2018-03-14) Kosmopoulos, Victor; Singleton, Steven; Homewood, TylerPurpose: Advancements in surgical repair and reconstruction of the anterior cruciate ligament (ACL) necessitate an appropriate animal model for pre-clinical testing. Furthermore, pre-clinical testing using cadaveric tissue is less readily available and comes at a greater cost as compared to animal tissue. Although the literature suggests the use of a pig model as a good biomechanical alternative for knee joint studies, only a limited number of studies have investigated similarities in knee joint anatomy. This study specifically aims to establish a method for comparing the geometric length, width and thickness of the ACL between humans and pigs in an effort to provide a measurement of proportionality between the two. Although the pig ACL may be smaller in overall size, we hypothesize that the dimensions will be proportional. Developing a repeatable measurement method and understanding geometric differences can help in study design (e.g., selecting suture size for ligament repair), control for experimental variation, and adds to our understanding of the mechanical differences that may be observed during testing. Although this is a preliminary study, future studies expanding this work will help determine if the pig is an appropriate alternative. Projecting ahead, as these examinations advance into in vivo studies, a validated pig model can serve as a way to follow long-term outcomes. Methods: Multi-planar digital images were acquired of a sectioned anterior cruciate ligament (ACL) from both a juvenile Yorkshire pig and a 78 year old male cadaver. Each image was imported and calibrated using imageJ (1.49v, National Institutes of Health, USA). Measurements were taken by two independent observers to determine ACL length, width, and thickness for comparison between human and pig ACL dimensions. A paired t-test was performed to establish inter-observer image measurement reliability (alpha=0.05). Results: No significant difference between readers was found in the ACL dimensions measured (p=0.23). The pig ACL had a length of 25.9-mm, a width of 10.6-mm, and a thickness of 4.1-mm. The length and thickness of the pig ACL were both 24% smaller than the human ACL. The width however did not match the scaling factor found in the other two dimensions resulting in only a 14% decrease as compared to the human ACL. Conclusions: This preliminary study establishes a reliable method for measurement of ligament dimensions. Although limited in sample size, the comparison between the ACL of a Yorkshire pig and a human was found to be proportional in two of the three dimensions studied. Moreover, visual comparison showed the ligaments to have very similar planar geometries. The study is currently ongoing and more samples are being collected and analyzed. Such geometric information will help add to our understanding of the ACL as a structure and add to the biomechanical tissue data available in the literature. Moving forward, we hope to use the pig as a model to study two novel ACL repair techniques.