Regis Renard | University of Arkansas for Medical Sciences (original) (raw)

Papers by Regis Renard

$Research paper thumbnail of Use of a fracture table for irreducible bipolar hemiarthroplasty dislocation: A case report$

International Journal of Case Reports and Images, 2017

Introduction: This article describes a case in which a fracture table was used to successfully re... more Introduction: This article describes a case in which a fracture table was used to successfully reduce a hip dislocation which was seemingly irreducible using other common methods. Case Report: A 53-year-old female presented to the authors’ facility with pain in the right hip and an infected posterolateral hip incision. Radiographs showed a posterior dislocation of the right hip status post bipolar hemiarthroplasty. The patient was taken to the operating room and successfully closed reduced using the Allis method. The infection was eradicated with IV antibiotics and I & D. After six weeks of post reduction, the patient presented to the emergency room with another right hip dislocation. A closed reduction was attempted using the same technique as before, but it was unsuccessful. Based on the patient’s chronic diagnosis (stage IV lung cancer) we chose to treat this again in a closed manner. The patient was transferred to a fracture table, and using longitudinal traction, a successful r...

MOJ Orthopedics & Rheumatology

The purpose of this study was to evaluate two different repair techniques for the primary repair ... more The purpose of this study was to evaluate two different repair techniques for the primary repair of patellar tendon ruptures. Using a cadaveric model, we biomechanically compared a double Krackow stitch with, and without cerclage augmentation. The specimens were tested at loads comparable to those likely to be encountered during an early rehabilitation program (approximately 40 Newtons) and for maximal mechanical parameters. The force at failure of the augmented repairs was 329 ± 89 Newtons (N), while the non-augmented repairs failed at 278 ± 87 N. However, the force required to produce significant gapping at the repair site was not significantly different between both repair techniques. Additionally, there was no significant difference between the mean stiffness of the repairs in both groups within the loading range from 10-100N. However, as expected, at loads greater than 100 N the cerclage augmented repairs were significantly stiffer. Most notably, there was no gap formation in any of the constructs tested at forces (40 N) comparable to those seen during an early passive extension and active flexion program. These data suggest that it may be possible to achieve the benefits of an early rehabilitation program without augmentation of the repair, and thus avoid the potential complications arising from this additional material.

The Journal of Arthroplasty

BACKGROUND Polymethylmethacrylate (PMMA) bone cement is commonly used in orthopedic surgery for i... more BACKGROUND Polymethylmethacrylate (PMMA) bone cement is commonly used in orthopedic surgery for implant fixation and local antibiotic delivery following surgical debridement. The incidence of nephrotoxicity necessitates the balance of antiinfective properties with the potential for toxicity. Thus, understanding antibiotic elution characteristics of different PMMA formulations is essential. We sought to address this by assessing elution of vancomycin, daptomycin, and tobramycin from Palacos LV (Palacos), Stryker Surgical Simplex P (Simplex), BIOMET Cobalt HV (Cobalt), and Zimmer Biomet Bone Cement R (Zimmer) radiopaque bone cements. METHODS Antibiotics were mixed with each cement formulation, and molds were used to produce beads of cement. Beads were incubated in phosphate-buffered saline at 37°C, and antibiotic elution was measured daily for 10 days with vancomycin and 5 days with daptomycin and tobramycin. Active antibiotic was quantified by serial dilution and comparison to the minimum inhibitory concentration. RESULTS The elution profiles of Simplex were significantly lower than all other cements with all antibiotics (P < .00093). Palacos exhibited a significantly higher vancomycin elution profile than all other cements (P < .00001). The difference in daptomycin elution profiles for Cobalt and Palacos was not significant (P > .43), but both were significantly higher than Zimmer (P < .0006). CONCLUSION Overall, Stryker Surgical Simplex P exhibits a significantly lower elution profile than all other cements tested. In general, Palacos LV exhibits an increased elution profile compared with other cements. This elution information may assist the surgeon in choosing different cement formulations for the local delivery of antibiotics.

$Research paper thumbnail of Current concepts review: Stress fractures of the foot$

Foot & ankle international, 2006

American Journal of Roentgenology, 2000

We determined the relative value of teleradiology and radiology resident coverage of the emergenc... more We determined the relative value of teleradiology and radiology resident coverage of the emergency department by measuring and comparing the effects of physician specialty, training level, and image display method on accuracy of radiograph interpretation. A sample of four faculty emergency medicine physicians, four emergency medicine residents, four faculty radiologists, and four radiology residents participated in our study. Each physician interpreted 120 radiographs, approximately half containing a clinically important index finding. Radiographs were interpreted using the original films and high-resolution digital monitors. Accuracy of radiograph interpretation was measured as the area under the physicians&amp;amp;amp;#39; receiver operating characteristic (ROC) curves. The area under the ROC curve was 0.15 (95% confidence interval [CI], 0.10-0.20) greater for radiologists than for emergency medicine physicians, 0.07 (95% CI, 0.02-0.12) greater for faculty than for residents, and 0.07 (95% CI, 0.02-0.12) greater for films than for video monitors. Using these results, we estimated that teleradiology coverage by faculty radiologists would add 0.09 (95% CI, 0.03-0.15) to the area under the ROC curve for radiograph interpretation by emergency medicine faculty alone, and radiology resident coverage would add 0.08 (95% CI, 0.02-0.14) to this area. We observed significant differences between the interpretation of radiographs on film and on digital monitors. However, we observed differences of equal or greater magnitude associated with the training level and physician specialty of each observer. In evaluating teleradiology services, observer characteristics must be considered in addition to the quality of image display.

$Research paper thumbnail of External validation of the clinical indications of computed tomography (CT) of the head in patients with low-energy geriatric hip fractures$

Injury, Jan 26, 2017

On evaluation of the clinical indications of computed tomography (CT) scan of head in the patient... more On evaluation of the clinical indications of computed tomography (CT) scan of head in the patients with low-energy geriatric hip fractures, Maniar et al. identified physical evidence of head injury, new onset confusion, and Glasgow Coma Scale (GCS)<15 as predictive risk factors for acute findings on CT scan. The goal of the present study was to validate these three criteria as predictive risk factors for a larger population in a wider geographical distribution. Patients ≥65 years of age with low-energy hip fractures from 6 trauma centers in a wide geographical distribution in the United States were included in this study. In addition to the relevant patient demographic findings, the above mentioned three criteria and acute findings on head CT scan were gathered as categorical variables. In total 799 patients from 6 centers were included in the study. There were 67 patients (8.3%) with positive acute findings on head CT scan. All of these patients (100%) had at least one criteria ...

Orthopedics

Superior labrum tears are common injuries in the throwing athlete. Sever contributing factors hav... more Superior labrum tears are common injuries in the throwing athlete. Sever contributing factors have been identified; however, the effects of instability on the superior labrum have not been studied. The goal of this cadaver study was to determine the effect of instability on superior labral strain in a model of the throwing motion. Six cadaver shoulders were mounted on an MTS machine with a strain gauge placed on the superior labrum. The shoulder was brought into the late cocking phase and strain measured before and after the introduction of a lesion to the inferior glenohumeral ligament to create anterior instability. Labral strain increased linearly in the late cocking phase of throwing in all specimens. Posterosuperior labral strain increased 160% in the unstable shoulders. This was a significant difference (P = .02). Instability increases strain in the posterosuperior labrum in the late cocking phase of throwing. This increased strain may render the labrum more prone to injury in...

Foot and ankle clinics, 2008

Advances in understanding age-related changes in articular cartilage, joint homeostasis, the natu... more Advances in understanding age-related changes in articular cartilage, joint homeostasis, the natural healing process after cartilage injury, and improved standards for evaluation of a joint surface made the ultimate goal of cartilage repair a possibility. New strategies for enhancement of articular cartilages' limited healing potential and biologic regeneration include advances in tissue engineering and the use of electromagnetic fields. This article reviews developments in basic science and clinical research made with these emerging technologies concerning treatment of articular cartilage defects and treatment of osteoarthritis of the ankle.

Orthopedics, 2007

Clinical Orthopaedics and Related Research®, 2014

The forearm is the second most common location for extremity compartment syndrome. Compliance is ... more The forearm is the second most common location for extremity compartment syndrome. Compliance is a physical property that describes a material&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s ability to expand with an increasing internal volume. The effect of circumferential dressings on extremity pressures has been investigated in various animal models and in some nonphysiologic mechanical models, but the importance of this effect has not been fully investigated in the human upper extremity. In addition, the physical property of compliance has not been reported in the analysis of compartment volume-pressure relationships. We created a physiologic cadaver model for acute compartment syndrome in the human forearm to determine (1) how much volume is required to reach the pressure threshold of 50 mm Hg in forearms, undressed and dressed with various circumferential dressings, (2) differences in forearm compliances that result from dressings, and (3) whether univalving or bivalving of those dressings adequately reduces compartment pressures. A sealed inflatable bladder was placed deep in the volar compartment of seven fresh-frozen cadaveric forearms and overlying fascia and skin were closed. Compartment pressures were measured as saline was infused in the bladder, and compliance was calculated from pressure versus volume curves. This was repeated for each specimen using five external wraps, splints, and casts. At a baseline of 50 mm Hg, each dressing then was univalved (and bivalved, when appropriate for the material) and the decrease in compartment pressure was measured. For each of the seven cadaver forearms, one test was performed without dressings and then for each of five dressing conditions. Forearms in fiberglass casts accommodated only a mean of 19 mL (SD, 11 mL; 95% CI, 9-28 mL) before reaching the 50 mm Hg pressure threshold, which was much less than in undressed forearms (mean, 77 mL; SD, 25 mL; 95% CI, 55-98 mL; p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Mean compliances were as follows: ACE™ wrap (1.75 mL/mm Hg; SD, 0.41 mL/mm Hg), Webril™ (1.54 mL/mm Hg; SD, 0.56 mL/mm Hg), Kling(®) (1.23 mL/mm Hg; SD, 0.52 mL/mm Hg), sugar tong splint (1.05 mL/mm Hg; SD, 0.52 mL/mm Hg), and fiberglass cast (0.38 mL/mm Hg; SD, 0.27 mL/mm Hg). Univalving of all circumferential wraps dropped the mean compartment pressure from the 50 mm Hg starting point: ACE™ (46%; SD, 14%), Webril™ (52%; SD, 20%), Kling(®) (70%; SD, 18%), sugar tong splint (52%; SD, 19%), and fiberglass cast (58%; SD, 7%), with p less than 0.001 for all dressings. We observed the compressive effect of various commonly used upper-extremity splints and wraps, finding the least amount of accommodation afforded by fiberglass casts. Univalve release resulted in reduction in forearm compartment pressures, even in fiberglass casts. A rigid circumferential dressing can have a dramatic effect on extremity compartment compliance. Contrary to common clinical teaching, univalving of forearm circumferential dressings effectively reduced compartment pressures, as shown in this physiologic model.

Topics in Bone Biology, 2007

The use of registered names, trademarks, etc. in this publication does not imply, even in the abs... more The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specifi c statement, that such names are exempt from the relevant laws and regulations and therefore free for general use.

Journal of Orthopaedic Trauma, 2002

To create a both-column acetabular fracture model with secondary congruence and to determine the ... more To create a both-column acetabular fracture model with secondary congruence and to determine the intraarticular loading characteristics present in simulated single-leg stance. The normal contact pressures on the weight-bearing portion of the acetabulum in simulated single-leg stance are different from those present in a both-column fracture model exhibiting secondary congruence. Cadaveric Biomechanical model. Biomechanical testing laboratory. Nine fresh frozen cadaveric hemipelves. Both-column fracture model with secondary congruence of the acetabular articular surface with respect to the femoral head was created and tested using Materials Testing Machine (MTS Systems Corp., Minneapolis, MN) and Fuji pressure-sensitive film (Sensor Products, Inc., East Hanover, NJ). Testing data recorded and analyzed comparing the fractured and unfractured states. With respect to the intact specimen, the contact area, mean pressure, and peak pressure in the dome region all increased (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.003) in the both-column model. The contact area in the anterior articular region decreased (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.02) as did the mean pressure (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.032). The posterior articular region demonstrated a trend toward decreased contact area and increased mean and peak pressures. Descriptively, the stress concentration shifted toward the fracture in all cases with the most anterior and most posterior articular regions having little contact in the fracture model. In the authors&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; both-column model of secondary congruence, the stress concentration during simulated single-leg stance was increased significantly in the dome of the acetabulum adjacent to the fracture line.

$Research paper thumbnail of †A biomechanical analysis of fixation constructs in high angle femoral neck fractures$

Journal of Orthopaedic Trauma, 2000

... Mark C.; Behrens, Fred F. Article Outline. Collapse Box Author Information. Orthopaedic Traum... more ... Mark C.; Behrens, Fred F. Article Outline. Collapse Box Author Information. Orthopaedic Trauma Service, New Jersey Medical School, Newark, NJ, USA. All authors of this paper received miscellaneous funding in support of this project. Purpose: In Pauwels' classification of ...

$Research paper thumbnail of Effect of displacement of fractures of the greater tuberosity on the mechanics of the shoulder$

The Journal of Bone and Joint Surgery, 2001

U sing a dynamic biomechanical model of malunion of the shoulder, we have determined the change i... more U sing a dynamic biomechanical model of malunion of the shoulder, we have determined the change in deltoid force required for abduction with various combinations of superior and posterior displacement of fractures of the greater tuberosity of the humerus. We tested eight fresh human cadaver shoulders in a dynamic shoulder-testing apparatus during cycles of glenohumeral abduction from 0° to 90°. The greater tuberosities were osteotomised and stabilised to represent malunion with combinations of superior and posterior displacements of 1 cm and less. The peak force was measured for each displacement in each specimen and statistically compared with values of no displacement using a repeated-measures analysis of variance.