Improving alignment in total knee arthroplasty: a cadaveric assessment of a surgical navigation tool with computed tomography imaging.

Purpose: To investigate the accuracy of an imageless, optical surgical navigation tool to assist with femoral and tibial bone cuts performed during TKA.

Patients And Methods: Six board-certified orthopedic surgeons participated in a laboratory cadaver investigation, performing femoral and tibial bone cuts with the assistance of a computer navigation tool. Femoral and tibial varus/valgus, tibial slope, femoral flexion, and both femoral and tibial rotation measurements from the device were compared with angular measurements calculated from computed tomography (CT) images of the knees.

Computer-Assisted Navigation Accurately Delivers Preoperative Targets for Acetabular Component Orientation During Direct Anterior Approach Total Hip Arthroplasty.

Despite its success, total hip arthroplasty (THA) remains associated with potentially significant complications associated with component malposition. Preoperative planning can mitigate some of these potential concerns; however, the accurate intraoperative delivery of preoperative targets can be challenging. Computer-assisted navigation may assist with intraoperative target delivery, although the integration of these two technologies is relatively uncommon.

Evaluation of alfaxalone total intravenous anesthesia in rabbits (Oryctolagus cuniculus) premedicated with dexmedetomidine or dexmedetomidine and buprenorphine.

Objective: To evaluate alfaxalone for total intravenous anesthesia (TIVA) in rabbits premedicated with dexmedetomidine or dexmedetomidine and buprenorphine.

Study Design: Crossover study (part 1) with observational study (part 2).

Animals: A total of eight New Zealand White rabbits (Oryctolagus cuniculus), four female and four male, aged 12-16 weeks and weighing 2.

Validation of a Novel Software Measurement Tool for Total Hip Arthroplasty.

Background Preoperative planning and postoperative evaluation of component position in total hip arthroplasty (THA) utilize specialized software that must be able to provide measurements that are both accurate and precise. A new software program for use in THA has recently been developed. We sought to evaluate the accuracy of this new software in comparison with two current, widely used software programs.

Compressed Paper as an Alternative to Corn Cob Bedding in Mouse () Cages.

Bedding material is a critical component of the mouse environment and affects animal wellbeing and research integrity. Corn cob (CC) bedding has been a common bedding choice in research despite several potential negative aspects of its use. We investigated the use of compressed paper (CP) bedding as a refinement to CC bedding.

Charged particle radiation induced changes to optical properties of acousto-optic materials.

We report on the measurement of the transmittance and reflectance of unpolarized light (425-700 nm) in three birefringent, acousto-optic materials, including quartz, lithium niobate, and tellurium dioxide, after exposure to varying fluences of proton radiation ($ {10^{14}} {-} {10^{18}}\;{\rm protons}/{{\rm cm}^2} $10-10protons/cm) delivered by a 10 keV hydrogen ion beamline. We observe a general monotonic decrease in transmittance with increasing fluence for all three materials, but with varying rates of change and critical points of change. Reflectance measurements also exhibit a general monotonic trend with fluence, but increases in quartz are observed versus decreases in both lithium niobate and tellurium dioxide.

Accuracy of Acetabular Component Positioning Using Computer-assisted Navigation in Direct Anterior Total Hip Arthroplasty.

Background  Appropriate component positioning in total hip arthroplasty (THA) is imperative for long-term survivorship. C-arm fluoroscopy provides visual guidance in the direct anterior approach (DAA), but it is limited by qualitative properties. Conversely, imageless computer-assisted navigation systems (CAS) provide surgeons with intraoperative, three-dimensional (3D) quantitative measurements for cup position, although the accuracy of such systems has not been extensively addressed in the DAA.

Intramuscular Administration of Alfaxalone Alone and in Combination for Sedation and Anesthesia of Rabbits ().

This study compared alfaxalone, alone and in combination with other medications, for sedative and anesthetic properties after intramuscular administration in New Zealand white rabbits. In the main portion of the study, 6 female rabbits were assigned to 5 treatment regimens in a blinded crossover design. Alfaxalone (6 mg/kg IM) was administered alone and in combination with each of the following: 0.

Effects of subcutaneous alfaxalone alone and in combination with dexmedetomidine and buprenorphine in guinea pigs (Cavia porcellus).

Objective: To characterize alfaxalone administered subcutaneously (SC) in guinea pigs, both alone and in combination with dexmedetomidine and buprenorphine.

Study Design: Prospective, blinded, crossover study.

Animals: A total of 15 healthy female guinea pigs weighing 400-600 g.

Protein-Energy Malnutrition Exacerbates Stroke-Induced Forelimb Abnormalities and Dampens Neuroinflammation.

Protein-energy malnutrition (PEM) pre-existing at stroke onset is believed to worsen functional outcome, yet the underlying mechanisms are not fully understood. Since brain inflammation is an important modulator of neurological recovery after stroke, we explored the impact of PEM on neuroinflammation in the acute period in relation to stroke-initiated sensori-motor abnormalities. Adult rats were fed a low-protein (LP) or normal protein (NP) diet for 28 days before inducing photothrombotic stroke (St) in the forelimb region of the motor cortex or sham surgery; the diets continued for 3 days after the stroke.

Animal Models of Zika Virus.

Zika virus has garnered great attention over the last several years, as outbreaks of the disease have emerged throughout the Western Hemisphere. Until quite recently Zika virus was considered a fairly benign virus, with limited clinical severity in both people and animals. The size and scope of the outbreak in the Western Hemisphere has allowed for the identification of severe clinical disease that is associated with Zika virus infection, most notably microcephaly among newborns, and an association with Guillian-Barré syndrome in adults.

Laser system refinements to reduce variability in infarct size in the rat photothrombotic stroke model.

Background: The rat photothrombotic stroke model can induce brain infarcts with reasonable biological variability. Nevertheless, we observed unexplained high inter-individual variability despite using a rigorous protocol. Of the three major determinants of infarct volume, photosensitive dye concentration and illumination period were strictly controlled, whereas undetected fluctuation in laser power output was suspected to account for the variability.

Nanoscale imaging of freestanding nitrogen doped single layer graphene.

Graphene can be p-type or n-type doped by introduction of specific species. Doping can modulate the electronic properties of graphene, but opening a sizable-well-tuned bandgap is essential for graphene-based tunable electronic devices. N-doped graphene is widely used for device applications and is mostly achieved by introducing ammonia into the synthesis gas during the chemical vapor deposition (CVD) process.

Short- and long-term memory are modulated by multiple isoforms of the fragile X mental retardation protein.

The diversity of protein isoforms arising from alternative splicing is thought to modulate fine-tuning of synaptic plasticity. Fragile X mental retardation protein (FMRP), a neuronal RNA binding protein, exists in isoforms as a result of alternative splicing, but the contribution of these isoforms to neural plasticity are not well understood. We show that two isoforms of Drosophila melanogaster FMRP (dFMR1) have differential roles in mediating neural development and behavior functions conferred by the dfmr1 gene.

Tibiofemoral compression force differences using laxity- and force-based initial graft tensioning techniques in the anterior cruciate ligament-reconstructed cadaveric knee.

Purpose: Our purpose was to document the tibiofemoral (TF) compression forces produced during clinical initial graft tension protocols.

Methods: An image analysis system was used to track the position of the tibia relative to the femur in 11 cadaveric knees. TF compression forces were quantified by use of thin-film pressure sensors.

A comparison of prospective and retrospective assessment of functional outcome after rotator cuff repair.

Prospective outcome studies are generally considered to be better than retrospective studies. The purpose of this study was to assess correlations between prospective and retrospective outcome assessment after rotator cuff repair. One-hundred and twelve patients (118 shoulders) with chronic rotator cuff tears were evaluated at a mean of 54 months (34-85) after rotator cuff repair, using several outcome measures including a retrospective assessment of improvement.

Resorbable fillers reduce stress risers from empty screw holes.

Background: Empty screw holes after hardware removal are stress risers that weaken bone and can lead to refracture in an active individual. We sought to reduce these stress risers. We hypothesize that resorbable screws used as hole fillers would (1) provide immediate strength and (2) maintain this strength during resorption.

Factors influencing patient satisfaction after rotator cuff repair.

A number of variables are used to assess the outcome of rotator cuff repair (RCR), including patient satisfaction. The purpose of this study was to determine the factors that affect patient satisfaction after RCR. The study assessed 112 patients (118 shoulders) with chronic rotator cuff tears preoperatively and at a mean of 54 months (range, 34-85 months) after RCR by using several functional outcome questionnaires and an evaluation of patient satisfaction.

Porcine small intestine submucosa for repair of goat meniscal defects.

This study evaluated the effectiveness of small intestine submucosa used as a graft to fill surgically created meniscal defects in a large animal model. Four goats underwent unilateral interior subtotal meniscectomies (approximately 70%) within the avascular portion of the medial meniscus. The contralateral meniscus acted as a control.

The diagnostic value of MRI in foot and ankle surgery.

Background: MRI is being used with increasing frequency and seems to have become more popular as a screening tool rather than as an adjunct to narrow specific diagnoses or plan operative interventions. Our hypothesis was that the rising accessibility of this test may be resulting in its overuse.

Methods: We retrospectively reviewed 221 consecutive patients referred over a 3-month period for treatment of a lower extremity problem to determine: (1) the number of patients who presented with an MRI already obtained from an outside source, (2) the number of patients who obtained an MRI from the foot and ankle specialist after referral, and (3) the number of times the foot and ankle specialist used these studies or found them helpful in the care of the patient.

Effects of initial graft tension on the tibiofemoral compressive forces and joint position after anterior cruciate ligament reconstruction.

Background: The initial tension applied to an anterior cruciate ligament graft at the time of fixation modulates knee motion and the tibiofemoral compressive loads.

Purpose: To establish the relationships between initial graft tension, tibiofemoral compressive force, and the neutral tibiofemoral position in the cadaveric knee.

Study Design: Controlled laboratory study.

Zolpidem reduces postoperative pain, fatigue, and narcotic consumption following knee arthroscopy: a prospective randomized placebo-controlled double-blinded study.

Sixty-eight patients undergoing outpatient knee arthroscopy for treatment of meniscal tears or loose bodies were divided into three treatment groups (zolpidem [24 patients], control [24 patients], and placebo [20 patients]). All groups received postoperative hydrocodone and ibuprofen. Patients in the zolpidem group received a single dose of zolpidem tartrate for the first seven postoperative nights.

Spinal epidural hematoma after a pathologic compression fracture: an unusual presentation of multiple myeloma.

Background Context: Spinal epidural hematoma can result from traumatic and atraumatic etiologies. Atraumatic spinal epidural hematomas have been reported as an initial presentation of multiple myeloma. There are no other reports previously describing spinal epidural hematoma after a pathologic spinal fracture.

Overutilization of shoulder magnetic resonance imaging as a diagnostic screening tool in patients with chronic shoulder pain.

This was a retrospective study of 101 consecutive patients (104 shoulders) with chronic, atraumatic shoulder pain who were evaluated by a fellowship-trained shoulder specialist. The patients were assessed with a complete history, physical examination, plain radiographs, Simple Shoulder Test, and visual analog scores of pain, shoulder function, and quality of life. Forty-one percent of the shoulders presented with shoulder magnetic resonance imaging (MRI).