@article{shapiro_feinstein_jewell_taylor_weinhold_draeger_2020, title={A Biomechanical Comparison of Modified Radioscapholunate Fusion Constructs for Radiocarpal Arthritis}, volume={45}, ISSN={["1531-6564"]}, DOI={10.1016/j.jhsa.2020.03.006}, abstractNote={Purpose This biomechanical study compared fixation constructs used in radioscapholunate (RSL) arthrodesis. We hypothesized that plates and screws, pin plate, and headless screws would all provide similarly stable fixation constructs. Methods We chose 27 fresh-frozen cadaveric extremities, 14 of which were matched pairs and randomized them into 3 groups to match age, body mass index, and sex. An RSL arthrodesis was simulated with plates and screws, pin plates, or headless compression screws via a standard dorsal approach to the wrist. Specimens were mounted into a custom jig and cycled through an arc of 120° for 5,000 cycles to simulate 6 weeks range of motion (ROM). A 9-mm stroke differential variable reluctance transducer recorded continuous displacement, and gross hardware failure in the form of screw or pin cutout was investigated after the simulation. Results Greater distraction across the RSL articulation was observed in the headless screws compared with the plate-and-screws and pin-plate constructs, with no difference between the plates and screws and pin plates. Greater average displacement was observed in the headless screws compared with the plate-and-screws and pin-plate constructs, with no difference between the pin plates and plates and screws. Gross hardware failure was observed least in plates and screws followed by pin plates. Conclusions Plate-and-screw and pin-plate constructs are biomechanically superior in resisting RSL distraction compared with headless compression screws for RSL arthrodesis over 6 weeks of simulated ROM in the absence of healing. Clinical relevance The results of this study demonstrated negligible arthrodesis site distraction in the plate-and-screws and pin-plate constructs when 6 weeks of ROM was simulated. When translated to a clinical scenario, these findings may allow earlier discontinuation of external immobilization after surgery.}, number={10}, journal={JOURNAL OF HAND SURGERY-AMERICAN VOLUME}, author={Shapiro, Joshua A. and Feinstein, Shawn D. and Jewell, Emily and Taylor, Ross R. and Weinhold, Paul and Draeger, Reid W.}, year={2020}, month={Oct} }
 @article{lindsay_ruppert_abumoussa_dahners_weinhold_2020, title={Benefits of additive manufacturing and micro and nano surface texture modifications on mechanical strength and infection resistance of skin-implant interfaces in rats}, volume={34}, ISSN={["1530-8022"]}, DOI={10.1177/0885328220903961}, abstractNote={Patients find existing exo-prostheses utilizing traditional socket connections uncomfortable and irritating, as they do not provide the dexterity and proprioception which is often expected by active patients. Transcutaneous osseointegrated implants are a potential solution, but carry risk of infection at the skin–implant interface. Histological and observational studies previously demonstrated that textured implants have both improved epidermal ingrowth and decreased skin retraction. This study aimed to determine effects on mechanical integration, barrier to bacterial colonization, and infection of the skin–implant interface using additive manufacturing and post-manufactured surface modifications. In this study, titanium alloy implants were made by either computer numerical control machining (CNC) or electron beam melting (EBM). Implants in each group were left either unaltered (CNC-control and EBM-control), acid etched (CNC-micro and EBM-micro), or oxidatively treated (CNC-nano and EBM-nano) creating six distinct surface textures. This study was divided into two phases, each utilizing 10 rats. Six implants—one of each texture—randomized for position were placed in each rat. Phase 1 animals healed for three weeks and skin-implant mechanical pull-off strength was measured. Phase 2 animals were challenged by S. aureus inoculation during the three-week healing process and serial dilutions of the sonicated implants were performed to quantify bacterial colonization. The three EBM implant groups had 830% greater force at pull-off compared to the three CNC groups. Additionally, the pull-off force of EBM-micro implants was 101% and 83% stronger, respectively, than EBM-nano and EBM-control implants. There was negligible mechanical attachment of skin to any CNC implant. Bacterial colonization counts were collectively 63% (P < 0.05) lower for EBM implants relative to CNC implants. CNC-control implants exhibited 90% (P < 0.01) greater bacterial colonization than EBM-controls. No significant differences in bacterial colonization were noted between the other implant groups. Both manufacturing technique and post-manufacturing surface texture modification affected the skin-implant interface’s mechanical integration and effectiveness as a barrier to infection. EBM manufacturing produced markedly superior transcutaneous implants compared to machining.}, number={9}, journal={JOURNAL OF BIOMATERIALS APPLICATIONS}, author={Lindsay, Christopher and Ruppert, David and Abumoussa, Sam and Dahners, Laurence and Weinhold, Paul}, year={2020}, month={Apr}, pages={1193–1200} }
 @article{shapiro_abumoussa_lindsay_mason_dahners_weinhold_2020, title={Locally delivered minocycline microspheres do not impair osseointegration of titanium implants in a rat femur model}, volume={20}, ISSN={["0972-978X"]}, DOI={10.1016/j.jor.2019.12.007}, abstractNote={The purpose of this study was to determine whether intramedullary administration of extended-release minocycline microspheres would affect osseointegration.Twenty-two rats were randomized to minocycline or saline femoral intramedullary injection followed by implantation of titanium alloy rods. Following euthanasia at four-weeks, pushout testing was performed and bone-volume-fraction assessed.Pushout strength was marginally greater in minocycline-treated implants (122.5 ± 39.1 N) compared to saline (96.9 ± 26.1 N) (P = 0.098). No difference was observed in energy to maximum load, mean stiffness, or peri-implant bone-volume-fraction (P > 0.05).Peri-implant minocycline administration did not impair implant fixation strength or peri-implant bone-volume, supporting its potential utility as an adjunct to intramedullary implants.}, journal={JOURNAL OF ORTHOPAEDICS}, author={Shapiro, Joshua A. and AbuMoussa, Samuel and Lindsay, Christopher P. and Mason, Gabriel B. and Dahners, Laurence E. and Weinhold, Paul S.}, year={2020}, pages={213–216} }
 @article{allen_bassil_berkoff_al maliki_draeger_weinhold_2019, title={Minocycline microspheres did not significantly improve outcomes after collagenase injection of tendon}, volume={16}, ISSN={["0972-978X"]}, DOI={10.1016/j.jor.2019.06.007}, abstractNote={Tetracycline antibiotics inhibit matrix metalloproteinases and pro-inflammatory cytokines implicated in the pathogenesis of tendinopathy, while microsphere formulations allow sustained release of drug contents. The purpose of this study was to evaluate the ability of a local minocycline microsphere injection to restore normal tendon properties in a rat model of collagenase-induced patellar tendinopathy.A total of 22 rats were randomly assigned to the control (n = 11) or minocycline (n = 11) group and received bilateral patellar tendon injections of collagenase. After 7 days, the minocycline group received the minocycline microsphere treatment and the control group received phosphate buffered solution. Pain was assessed via activity monitors and Von Frey filament testing. At 4 weeks post-collagenase injections, animals were euthanized.Cage crossings significantly decreased among all rats 2-3 days following each injection period, however, tactile allodynia measures did not reflect this injury response. Biomechanical properties, interleukin-1 beta levels, and glycosaminoglycan content did not differ between groups. While not statistically significant, levels of leukotriene B4 were lower in the minocycline group compared to controls (p = 0.061), suggesting a trend.Our study further characterizes the collagenase model of tendinopathy by demonstrating no evidence of central sensitization with collagenase-induced injury. We found no adverse effect of intratendinous injections of minocycline-loaded poly-lactic-co-glycolic acid microspheres, although no therapeutic effect was observed. Future studies involving a more substantial tendon injury with a greater inflammatory component may be necessary to more thoroughly evaluate the effects of minocycline on tendon pathology.}, number={6}, journal={JOURNAL OF ORTHOPAEDICS}, author={Allen, Andrew D. and Bassil, Alex M. and Berkoff, David J. and Al Maliki, Mohammed and Draeger, Reid W. and Weinhold, Paul S.}, year={2019}, pages={580–584} }
 @article{efird_fletcher_draeger_spang_dahners_weinhold_2018, title={Deferoxamine-Soaked Suture Improves Angiogenesis and Repair Potential After Acute Injury of the Chicken Achilles Tendon}, volume={6}, ISSN={["2325-9671"]}, DOI={10.1177/2325967118802792}, abstractNote={A major obstacle to the treatment of soft tissue injuries is the hypovascular nature of the tissues. Deferoxamine (DFO) has been shown to stimulate angiogenesis by limiting the degradation of intracellular hypoxia-inducible factor 1-alpha.DFO-saturated suture would induce angiogenesis and improve the markers of early healing in an Achilles tendon repair model.Controlled laboratory study.Broiler hens were randomly assigned to the control (CTL) group or DFO group (n = 9 per group). The right Achilles tendon was partially transected at its middle third. The defect was surgically repaired using 3-0 Vicryl suture soaked in either sterile water (CTL group) or 324 mM DFO solution (DFO group). All animals were euthanized 2 weeks after the injury, and the tendon was harvested. Half of the tendon was used to evaluate angiogenesis via hemoglobin content and tissue repair via DNA content and proteoglycan (PG) content. The other half of the tendon was sectioned and stained with hematoxylin and eosin, safranin O, and lectin to evaluate vessel density.Hemoglobin content (percentage of wet tissue weight) was significantly increased in the DFO group compared with the CTL group (0.081 ± 0.012 vs 0.063 ± 0.016, respectively; P = .046). DNA content (percentage of wet tissue weight) was also significantly increased in the DFO group compared with the CTL group (0.31 ± 0.05 vs 0.23 ± 0.03, respectively; P = .024). PG content (percentage of wet tissue weight) was significantly decreased in the DFO group compared with the CTL group (0.26 ± 0.02 vs 0.33 ± 0.08, respectively; P = .035). Total chondroid area (number of vessels per mm2 of tissue area evaluated) was significantly decreased in the DFO group compared with the CTL group (17.2 ± 6.6 vs 24.6 ± 5.1, respectively; P = .038). Articular zone vessel density (vessels/mm2) was significantly increased in the DFO group compared with the CTL group (7.1 ± 2.5 vs 2.1 ± 0.9, respectively; P = .026).The significant increase in hemoglobin content as well as articular zone vessel density in the DFO group compared with the CTL group is evidence of increased angiogenesis in the fibrocartilaginous region of the tendon exposed to DFO. The DFO group also displayed a significantly greater level of DNA and significantly lower level of PG, suggesting enhanced early healing by fibrous tissue formation.Stimulating angiogenesis by DFO-saturated suture may be clinically useful to improve healing of poorly vascularized tissues.}, number={10}, journal={ORTHOPAEDIC JOURNAL OF SPORTS MEDICINE}, author={Efird, William M. and Fletcher, Alex G. and Draeger, Reid W. and Spang, Jeffrey T. and Dahners, Laurence E. and Weinhold, Paul S.}, year={2018}, month={Oct} }
 @article{ruppert_harrysson_marcellin-little_dahners_weinhold_2018, title={Improved osseointegration with as-built electron beam melted textured implants and improved peri-implant bone volume with whole body vibration}, volume={58}, ISSN={["1873-4030"]}, DOI={10.1016/j.medengphy.2018.05.003}, abstractNote={Transcutaneous osseointegrated prostheses provide stable connections to the skeleton while eliminating skin lesions experienced with socket prosthetics. Additive manufacturing can create custom textured implants capable of interfacing with amputees' residual bones. Our objective was to compare osseointegration of textured surface implants made by electron beam melting (EBM), an additive manufacturing process, to machine threaded implants. Whole body vibration was investigated to accelerate osseointegration. Two cohorts of Sprague-Dawley rats received bilateral, titanium implants (EBM vs. threaded) in their tibiae. One cohort comprising five groups vibrated at 45 Hz: 0.0 (control), 0.15, 0.3, 0.6 or 1.2 g was followed for six weeks. Osseointegration was evaluated through torsional testing and bone volume fraction (BV/TV). A second cohort, divided into two groups (control and 0.6 g), was followed for 24 days and evaluated for resonant frequency, bone-implant contact (BIC) and fluorochrome labeling. The EBM textured implants exhibited significantly improved mechanical stability independent of vibration, highlighting the benefits of using EBM to produce custom textured surfaces. Bone formation on and around the EBM textured implants increased compared to machined implants, as seen by BIC and fluorescence. No difference in torque, BIC or fluorescence among vibration levels was detected. BV/TV significantly increased at 0.6 g compared to control for both implant types.}, journal={MEDICAL ENGINEERING & PHYSICS}, author={Ruppert, David S. and Harrysson, Ola L. A. and Marcellin-Little, Denis J. and Dahners, Laurence E. and Weinhold, Paul S.}, year={2018}, month={Aug}, pages={64–71} }
 @article{cavanaugh_tan_norris_hardee_weinhold_dahners_orndorff_shirwaiker_2016, title={Evaluation of silver-titanium implants activated by low intensity direct current for orthopedic infection control: An in vitro and in vivo study}, volume={104}, ISSN={["1552-4981"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84976501648&partnerID=MN8TOARS}, DOI={10.1002/jbm.b.33451}, abstractNote={Abstract Silver is an alternative antimicrobial of interest for the prophylaxis of prosthetic infections and electrical activation is known to augment its oligodynamic efficacy. In this study, we evaluated the in vitro and in vivo efficacy of a silver (Ag)‐titanium (Ti) implant activated by 30 µA direct current compared with three controls – passive Ag‐Ti, active Ti‐Ti, and passive Ti‐Ti. We hypothesized that the experimental group would provide better resistance to pathogenic colonization on the implant. Modified Kirby‐Bauer technique was used to evaluate in vitro efficacy of the four groups against five bacteria and one fungus. For in vivo evaluation, forty‐eight rats were divided into four groups. The implant was secured in a wound cavity along the posterior margin of the femur. The wound was inoculated with 7.5 × 10 5 CFU of Staphylococcus aureus . Rats were euthanized 14 days postsurgery and quantitative cultures were performed on the implant segments and the wound cavity tissue. In vitro tests showed that the growth of all six pathogens was inhibited around the active Ag anodes of the experimental group. In vivo , none of the four groups were able to prevent wound infection, but the experimental group resulted in reduced colonization. The mean bacterial loads on Ti segments were significantly lower in the implants which also had an Ag segment ( p = 0.0007), and this effect was more pronounced with electrical activation ( p = 0.0377). The results demonstrate the antimicrobial potential of LIDC‐activated Ag‐Ti implants. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1023–1031, 2016.}, number={5}, journal={JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS}, author={Cavanaugh, Daniel L. and Tan, Zhuo and Norris, James P. and Hardee, Amelia and Weinhold, Paul S. and Dahners, Laurence E. and Orndorff, Paul E. and Shirwaiker, Rohan A.}, year={2016}, month={Jul}, pages={1023–1031} }
 @article{pamukoff_pietrosimone_lewek_ryan_weinhold_lee_blackburn_2016, title={Immediate effect of vibratory stimuli on quadriceps function in healthy adults}, volume={54}, ISSN={["1097-4598"]}, DOI={10.1002/mus.25081}, abstractNote={The purpose of this study was to compare the effect of whole body vibration (WBV) and local muscle vibration (LMV) on quadriceps function.Sixty adults were randomized to WBV, LMV, or control groups. Quadriceps function [Hoffmann (H)-reflex, active motor threshold (AMT), motor evoked potential (MEP) and electromyographic amplitude, peak torque (PT), rate of torque development (RTD), and central activation ratio (CAR)] was assessed before and immediately after and 10 and 20 minutes after interventions.WBV improved PT, CAR, AMT, EMG, and MEP amplitude, and EMG amplitude and CAR were greater than control after application. LMV improved EMG amplitude and AMT, and EMG amplitude was greater than control after application. AMT remained lower 10 and 20 minutes after WBV and LMV. No differences were noted between LMV and WBV. Vibration did not influence H-reflex or RTD.WBV and LMV increased quadriceps function and may be used to enhance the efficacy of strengthening protocols. Muscle Nerve 54: 469-478, 2016.}, number={3}, journal={MUSCLE & NERVE}, author={Pamukoff, Derek N. and Pietrosimone, Brian and Lewek, Michael D. and Ryan, Eric D. and Weinhold, Paul S. and Lee, Dustin R. and Blackburn, J. Troy}, year={2016}, month={Sep}, pages={469–478} }
 @article{pamukoff_pietrosimone_lewek_ryan_weinhold_lee_blackburn_2016, title={Whole-Body and Local Muscle Vibration Immediately Improve Quadriceps Function in Individuals With Anterior Cruciate Ligament Reconstruction}, volume={97}, ISSN={["1532-821X"]}, DOI={10.1016/j.apmr.2016.01.021}, abstractNote={Objective To determine the immediate effects of a single session of whole-body vibration (WBV) and local muscle vibration (LMV) on quadriceps function in individuals with anterior cruciate ligament reconstruction (ACLR). Design Singe-blind, randomized crossover trial. Setting Research laboratory. Participants Population-based sample of individuals with ACLR (N=20; mean age ± SD, 21.1±1.2y; mean mass ± SD, 68.3±14.9kg; mean time ± SD since ACLR, 50.7±21.3mo; 14 women; 16 patellar tendon autografts, 3 hamstring autografts, 1 allograft). Interventions Participants performed isometric squats while being exposed to WBV, LMV, or no vibration (control). Interventions were delivered in a randomized order during separate visits separated by 1 week. Main Outcome Measures Quadriceps active motor threshold (AMT), motor-evoked potential (MEP) amplitude, Hoffmann reflex (H-reflex) amplitude, peak torque (PT), rate of torque development (RTD), electromyographic amplitude, and central activation ratio (CAR) were assessed before and immediately after a WBV, LMV, or control intervention. Results There was an increase in CAR (+4.9%, P=.001) and electromyographic amplitude (+16.2%, P=.002), and a reduction in AMT (–3.1%, P<.001) after WBV, and an increase in CAR (+2.7%, P=.001) and a reduction in AMT (–2.9%, P<.001) after LMV. No effect was observed after WBV or LMV in H-reflex, RTD, or MEP amplitude. AMT (–3.7%, P<.001), CAR (+5.7%, P=.005), PT (+.31Nm/kg, P=.004), and electromyographic amplitude (P=.002) in the WBV condition differed from the control condition postapplication. AMT (–3.0% P=.002), CAR (+3.6%, P=.005), and PT (+.30Nm/kg, P=.002) in the LMV condition differed from the control condition postapplication. No differences were observed between WBV and LMV postapplication in any measurement. Conclusions WBV and LMV acutely improved quadriceps function and could be useful modalities for restoring quadriceps strength in individuals with knee pathologies.}, number={7}, journal={ARCHIVES OF PHYSICAL MEDICINE AND REHABILITATION}, author={Pamukoff, Derek N. and Pietrosimone, Brian and Lewek, Michael D. and Ryan, Eric D. and Weinhold, Paul. S. and Lee, Dustin R. and Blackburn, J. Troy}, year={2016}, month={Jul}, pages={1121–1129} }