Research Projects

Internal Fixation of a Standard Joint Depressed Intraarticular (Sanders IIb) Calcaneus Fracture: Biomechnical Analysis of a Novel Techique.
Orthopedic Research Center - Dr. J. Nelson

An ideal calcaneal construct would include minor hardware prominence, sturdy posterior facet fixation and nomial soft tissue disruption. The purpose of this study was to develop such a novel construct for fixation of the calcaneous and undertake a quality biomechanical analysis which will compare our new techique to the standard calcaneus fixation. Resutls show that the novel screw fixation technique had significantly less movement compared to the standard plate fixation.

Compression Strength and Porosity of Single-Antibiotic Cement Vacuum-Mixed with Vancomycin
Orthopedic Research Center

The addition of antibiotics to cement allows the theoretical benefit of providing high local drug concentrations with less risk of systemic complications. A major drawback of this combination is the detrimental effect antibiotics have on the mechanical properties of bone cement. The study was designed to determine how much Vancomysin can be added while maintaining at least 70 MPa of compressive strength. Results showed that up to 6 grams of Vancomysin can be added without have a determintal effect. Amounts larger than 6 grams could possible effect the bonds the cement needs to maintain its stiffness.

Comparision of Different Implants for Fixation of Posterior Malleolus Fractures
Orthopedic Research Center

The aim of the study was to present an alternative way of fixating a posterior malleolus fracture. We believed that the Tight Rope system will allow for equal to better fixation than compression screws during a static load and fatigue testing. Results showed that the there was no significant difference between the Tight Rope system and the screw fixation technique. Clinicially the smaller the posterior fragment of the tibia the more likely a tight rope sytem could be used.

Intrawound Vancomycin Powder Decreases Acute, Deep Staphylococcus aureus Infection Rates in Posterior
Instrumented Spinal Arthrodeses
Aaron Heller, BA, T32 Clinical Research Scholar
Terence E. McIff, PhD, Co-Investigator
Surgical site infection is a serious complication for patients undergoing instrumented spinal surgery.  Staphylococcus aureus is the most common causative agent associated with post-op wound infections. Recent studies have reported a decreased infection rate with intrawound vancomycin use in spine surgeries. We sought to determine if intrawound vancomycin would decrease the rates of acute, deep S. aureus infections in our posterior instrumented spinal arthrodesis patients. Intrawound vancomycin has decreased the rate of acute, deep S. aureus infections in our posterior instrumented spinal fusion patient population from 1.61% to 0. Our vancomycin group was significantly older and underwent a significantly greater number of surgeries with pelvic fixations, though had fewer infections.  This work is adding to the growing body of evidence in support of this effective adjuvant to standard antimicrobial prophylaxis.

Effects of Negative Pressure to Promote Tissue Growth into Porous Metal Implants
Primary Researcher: Jeff Lamping, MS
This two-part study investigates the application of negative pressure wound therapy (NPWT) and its effect on tissue growth in a goat model. The first part of the study investigates the effect of NPWT on the soft tissue growth into a subdermal porous metal implant. The second part of the study focuses on the effect of NPWT on bone growth into a porous metal implant used to repair a segmental bone defect. The goal of this pilot study aims to show the effectiveness of NPWT applied to the treatment of segmental bone defects and to serve as a basis for further research on this topic.

Collagen Composition and Neural Properties of the Glenoid Capsule and Labrum may Contribute to Glenohumeral Joint Laxity
Primary Researcher: Jessica Witherspoon, DPT
Additional Research Support: Dan Sisk, BA
This study investigates correlations between collagen composition (type 1 to type 3 collagen ratio), innervation density, and joint laxity in the human shoulder. Mechanical testing of cadaveric shoulders will be used to measure joint laxity. Capsular and labral samples harvested from the glenohumeral joint will be analyzed to measure collagen type ratio, mechanoreceptor distribution as well as innervation density. The goal of this study is to provide clinicians with a greater understanding of how the collagen composition and neural properties may contribute to increased joint laxity, and ultimately recurrent instability.

The Effect of Nebulized Captopril on Fat Induced Lung Pathology
Primary Researcher: Aaron Heller, BA
Additional Research Support: Daniel Rhoades, BA
Fat embolism research has a long history at the Kansas University Medical Center and within the Department of Orthopedic Surgery. Fat emboli occur in 90% of patients with long bone fractures, and up to 20% of them will develop respiratory distress associated with these emboli. Our lab has previously characterized the pulmonary damage caused by fat emboli and demonstrated that injections of the ace inhibitor captopril or the angiotensin receptor blocker losartan attenuates this pathology. Currently, over concerns of administering an anti-hypertensive systemically to an already hypotensive trauma patient, we are testing the efficacy of delivering captopril locally to the lungs by nebulization.

Transcutaneous Osseointegration for Weight Bearing Prostheses
Primary Researchers: Aly Boyer, BA; Kevin Colbert, BS
This study investigates the application of a porcine model to address wound healing and infection concerns at the implant/skin interface. A gait study will enable a better understanding of loading associated with lower limb prostheses. An associated soft tissue finite element model focuses on the biomechanics involved with the prosthetic limb. The goal of this pilot study aims to show the effectiveness of transcutaneous osseointegrated prostheses and to serve as a basis for further research on this topic.