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Memphis, TN, United States

Crockarell J.R.,Campbell University | Snearly C.M.,tion Orthopaedic Research Center
Journal of Arthroplasty | Year: 2012

Roentgen Monographic Analysis Tool (ROMAN) and Hip Analysis Suite (HAS) were used to analyze radiographs of a phantom hip model. Displacements of known magnitude and direction were produced using dial micrometers. Differences between the known displacement and the programs' reported displacement were compared. Hip Analysis Suite was superior with a median error of 0.075 mm (range, 0.019-0.205 mm) compared with 0.137 mm (range, 0.008-0.389 mm) for ROMAN (P = .002). Hip Analysis Suite was also more precise when evaluating intraobserver variability, with a standard deviation between radiographs of 0.007 mm (range, 0.002-0.009 mm), whereas ROMAN's standard deviation was 0.117 mm (range, 0.007-0.153 mm). Repeatability for HAS was 0.019 mm and 0.325 mm for ROMAN. Hip Analysis Suite was more accurate and precise than ROMAN under experimental conditions with digital radiographs. © 2012 Elsevier Inc. Source

Zhang K.,tion Orthopaedic Research Center | Mihalko W.M.,University of Memphis
Clinical Orthopaedics and Related Research | Year: 2012

Background Although normal cruciate ligaments and those in patients with osteoarthritic (OA) knees contain mechanoreceptors, it is unclear whether they are present after functioning in a cruciate-retaining total knee arthroplasty (TKA). Questions/purposes We therefore determined if the areas occupied by mechanoreceptors in the human posterior cruciate ligament (PCL) are similar in patients with osteoarthritis and in patients who have had TKA with retention of the PCL. Methods We identified five cruciate-retaining TKA specimens from a retrieval program and obtained five PCLs during cruciate-sacrificing TKA from patients with OA; the retrieved specimens had been in place 5 to 12 years. The whole en bloc PCL specimens were harvested for the study. These specimens were then sectioned to a thickness of 8 lm and mounted on microscope slides. Two transverse cross-sections from the distal third from each specimen 100 lm apart were then subjected to immunohistochemistry with neurofilament protein (NFP) and S-100 protein. Results All five PCL specimens in each group revealed multiple areas of positive stained elements with both S-100 protein and NFP immunohistochemical staining. Morphologically, these elements appear to correspond to Pacinilike, Golgilike, and fusiform types of mechanoreceptors. We observed no difference in positive staining mechanoreceptor elements as a percentage of area in the osteoarthritis and TKA groups. Conclusion Mechanoreceptors appear to occupy similar areas before and after implantation of a TKA. Clinical Relevance If mechanoreceptors continue to function after cruciate-retaining TKA, then it may continue to participate in proprioception of the knee after TKA. © The Association of Bone and Joint Surgeons® 2012. Source

Komatsu D.E.,tion Orthopaedic Research Center | Warden S.J.,Indiana University
Journal of Cellular Biochemistry | Year: 2010

Fracture repair is a complex process involving timed cellular recruitment, gene expression, and synthesis of compounds that regenerate native tissue to restore the mechanical integrity, and thus function of injured bone. While the majority of fractures heal without complication, this takes time and a subset of patients (∼10%) experience healing delays, extending their morbidity and treatment costs. Consequently, there is a need for efficacious therapeutics for the intervention of fracture healing. Recent studies into the molecular control of fracture repair and advances in the understanding of the skeleton as a whole have resulted in the identification of numerous novel targets and compounds for such intervention. These include traditional agents such bone morphogenetic proteins and other growth factors, but also relatively newer compounds such as parathyroid hormone and modulators of the Wnt signaling pathway. These agents, along with others, are discussed in the current article in terms of their investigative status and potential for clinical implementation. Hopefully, these agents, as well as others yet to be discovered, will demonstrate sufficient clinical utility for successful intervention of fracture healing. This may have significant implications for the duration of morbidity and costs associated with traumatic bone fractures. © 2009 Wiley-Liss, Inc. Source

Mihalko W.M.,University of Memphis | Mihalko W.M.,tion Orthopaedic Research Center | Conner D.J.,tion Orthopaedic Research Center | Conner D.J.,University of Memphis | And 2 more authors.
Clinical Orthopaedics and Related Research | Year: 2012

Background Assessment of patient function after TKA often focuses on implant alignment and daily activity capabilities, but the functional results and kinematics of the TKA are not easily predicted by some of these parameters during surgery. Questions/purposes We asked whether differences in implant alignment in the transverse plane may affect fluorokinematics and be one of the many variables that help explain the discrepancies in fluorokinematic results. Methods We utilized a computer model (LifeMODTM/ KneeSIM; LifeModeler, Inc, San Clemente, CA, USA) to show variability in polyethylene contact patterns. We imported components of a cruciate-retaining TKA into the model and subjected the systems to a simulated lunge. We modeled five different combinations of implant positioning in the transverse plane of both the femoral and tibial components in internal or external rotation and compared the resulting changes in joint rotations and displacements of these five variations to those for published fluorokinematic observations using the same modeled lunge-type maneuver for five patients. Results We observed variations in AP translation of the lateral and medial femoral condyles resembling several of those in the literature for individual patients with the same cruciate-retaining knee implant. The largest AP translational changes were seen with the tibia internally rotated 5°. Using the five different implant transverse plane alignment scenarios resulted in a coefficient of determination of 0.6 for the linear regression when compared to five subjects from a published fluorokinematic study. Conclusions Variations in implant positioning may be responsible for variations in fluorokinematics reported for individual subjects with the same implant design. Clinical Relevance If validated computermodeling can aid surgeons to predict the effects of individual implant alignment variations in TKA kinematics, a more personalized approach to implant positioning during TKA can be implemented.© The Association of Bone and Joint Surgeons® 2011. Source

Lindsey J.A.,University of Memphis | Conner D.,University of Memphis | Godleski P.,University of Tennessee Health Science Center | Perkinson B.,University of Tennessee Health Science Center | And 4 more authors.
Journal of Long-Term Effects of Medical Implants | Year: 2010

One of the common reasons for early revision or poor outcome in total knee arthroplasty is due to patellar maltracking, loosening, or pain. Th e analysis of how the patellofemoral mechanism operates and wears in vivo has not been a focus of many retrieval studies. Th is paper describes the wear pattern observed on patellar buttons from well-functioning TKA specimens that were harvested as part of a donor program. Th e attempt was to describe the variations in wear patterns to see if any commonalities existed that may predict a well-functioning patellofemoral mechanism after TKA. © 2010 by Begell House, Inc. Source

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