Standard Insertion Research Articles

Is Low-current Search a Risk Factor in Peripheral Nerve Localization?

We thank Dr. Al-Nasser for the attentive reading of our article regarding the use of continuous peripheral nerve blocks after orthopedic surgery.1We understand and accept some remarks regarding the possible risk of neuropathy for intensities lower than 0.5 mA during the nerve stimulation procedure. Dr. Al-Nasser's concerns, which have already been evoked by Auroy et al. ,2are supported by recent articles reporting that for low-intensity and short-duration nerve stimulation (< 0.5 mA, 0.1 ms), needle–nerve contact can be obtained without any muscle movement3or pain.4However, some points must be clarified: Research of a minimal intensity during nerve stimulation was not a part of our study design; all of the studies reported by Al-Nasser were related to single-shot blocks and not continuous peripheral nerve blocks; the authors do not decide, regardless of whether it seems important, that one element or another is a risk factor—rather, the multivariate analysis by logistic regression concludes that; the authors5,6who reported the vicinity of nerve and needle tip for values less than 0.5 mA used theoretical biophysics data but did not check their data in clinical practice (ultrasound studies) or in animals; and it was recently reported that signs of nerve inflammation after a peripheral nerve block appeared only after a minimal low-intensity threshold value of 0.2 mA.7The stimulating current at which a needle is sufficiently close for a successful block but still at a safe distance from the nerve to avoid injury is unknown.8In our study, the placement of the needle was considered successful when a specific muscle contraction was obtained at a current output of less than 0.5 mA (1 Hz and impulse duration of 0.1 ms). The current was then gradually decreased until the muscle twitch stopped between 0.4 and 0.2 mA. Nerve stimulation below 0.2 mA was never sought. Intensity of less than 0.5 mA did not seem to be a risk factor. Several elements might explain that: All continuous peripheral nerve blocks were performed by highly trained anesthesiologists following standardized insertion techniques; the nerve stimulators, which delivered the dialed current, were regulated to deliver the actual current; the catheters were inserted for values between 0.2 and 0.5 mA; and there was no motor response for intensity of less than 0.2 mA.Most importantly, the risk of nerve lesion increases when a physician uses an old nerve stimulator that reports only the theoretical current and not the current actually delivered, which can be lower. If anesthesiologists use this standard of nerve stimulator, they should not set their threshold at 0.5 mA, but invest in a new nerve stimulator to limit the risk of nerve injury.*Lapeyronie University Hospital, Montpellier, France. x-capdevila@chu-montpellier.fr

News: data-driven enterprise - slouching toward the semantic Web

Many organizations are still trying to figure out how to build a mostly object-oriented Web services system. In explaining the semantic Web's enterprise possibilities, the author emphasizes the benefits of direct access to the data within applications rather than integrating the applications themselves. Some industry observers still see the semantic Web as a theoretician's dream. Enterprises are still trying to figure out how to integrate applications via Web services and service-oriented architectures, so asking them to begin drawing up semantic Web capable taxonomies anytime soon isn't realistic. The knowledge sharing that would entice enterprises would allow relational databases to directly import ontologies and rules just as easily as they use standard SQL insert, update, and delete statements. Ontologies can act as the glue between multiple information sources, providing a consistent view of all the information, augmenting it and filling in the gaps. The best route for success will be to stop emphasizing what the semantic Web might do in the future and work instead on practical steps to improve the architecture.

Detection of Inadvertent Airway Intubation During Gastric Tube Insertion: Capnography Versus a Colorimetric Carbon Dioxide Detector

In the medical intensive care unit at the University of Virginia Health System, capnography is used to detect end-tidal carbon dioxide to protect patients from inadvertent airway cannulation during placement of gastric tubes. To compare the method in which capnography is used with a method in which a colorimetric carbon dioxide detector is used and to determine what variables affect accurate placement of gastric tubes. A prospective convenience sample of 195 gastric tube insertions was studied in 130 adult patients in a medical intensive care unit. Standard insertions of gastric tubes (done with capnography) were simultaneously monitored by using a disposable colorimetric device, with a color change indicating the presence of carbon dioxide. Insertion variables included tube type (60% Salem sump tubes, 40% soft-bore feeding tubes), route of insertion (71% oral, 29% nasal), mechanical ventilation (81%), and decreased mental status (72%). Carbon dioxide was successfully detected with the colorimetric indicator (within seconds) in all insertions in which carbon dioxide was detected by capnography. When carbon dioxide was detected (27% of insertions), the tubes were withdrawn and reinserted. Carbon dioxide detection during tube placement was significantly associated with nasal insertions (P = .03) and spontaneously breathing/nonintubated status (P = .01) but not with mental status or tube type. A colorimetric device is as accurate as capnography for detecting carbon dioxide during placement of gastric tubes.

A laboratory study to determine the effects of universal and rotating ultrasonic inserts on wrist movement and scaling time efficiency of dental hygienists

The purpose of this study was to determine if differences existed in range of wrist movements and scaling time efficiency of dental hygienists using a rotating ultrasonic insert when compared with a standard universal insert. A convenience sample of 32 consenting experienced dental hygienists who met inclusion criteria was invited to participate. Using a cross-over research design, the 32 participants were randomly assigned to one of the two subgroups. Subgroup A (n = 16) used the rotating universal ultrasonic insert on a typodont, rested for 15 min and the standard universal insert on a different typodont. Subgroup B (n = 16) used the standard universal ultrasonic insert on a typodont, rested for 15 min and the rotating universal ultrasonic insert on a different typodont. Each participant used the rotating and standard universal ultrasonic scaling inserts to remove 2 cm3 artificial calculus from two different typodonts for up to 15 min per insert. Scaling time efficiency was determined using a Modified Volpe-Manhold Calculus Index, measuring the amount of artificial calculus remaining after ultrasonic scaling. While scaling, each participant wore the WristSensor goniometry gloves, which determined changes in wrist movements (flexion and extension and ulnar and radial deviations), measured as a deviation from the neutral position. A paired t-test (P = 0.05) using 30 subjects with useable data, revealed no statistically significant differences between the two different inserts in terms of wrist movements and scaling time efficiency. A multivariate analysis of variance revealed no statistically significant differences in the percentage of time dental hygienists were in high, medium or low-risk posture categories while using the rotating ultrasonic insert compared with the standard universal insert. Based on the results of this laboratory study, dental hygienists using a rotating ultrasonic insert appear to experience no ergonomic advantage in terms of wrist postures or timesavings over a standard insert.

Insufflation Techniques in Gynecologic Laparoscopy

Our objectives were to assess the safety and efficacy of different insufflation methods in women undergoing laparoscopy and to develop a model for selection of the appropriate insufflation technique based on the patient's characteristics and surgeon's experience. We performed a retrospective analysis of laparoscopic procedures on 3086 women over a 13-year period at the University of Louisville Hospital, Louisville, KY. All laparoscopic procedures were performed on an outpatient basis by residents under faculty supervision. Five different insufflation techniques were evaluated: standard transumbilical insufflation, open laparoscopy, transuterine insufflation, subcostal insufflation, and direct trocar insertion technique. Body mass index and previous abdominal surgeries were identified as the most important factors in the selection of the most successful insufflation method based on the surgeon's experience, using data mining techniques. During the first insufflation attempt, we were successful at achieving a pneumoperitoneum 94.7% of the time. This number increased to 98.1% when we switched to a second alternative insufflation method. In all, there were 5 complications out of 3086 patients (0.16%) after all insufflation techniques.

Nasopharyngeal Decolonization of Methicillin-Resistant Staphylococcus aureus Can Reduce PEG Peristomal Wound Infection

The aim of this study is to determine whether nasopharyngeal decolonization of methicillin-resistant Staphylococcus aureus (MRSA) can reduce peristomal wound infection shortly after percutaneous endoscopic gastrostomy (PEG) placement. Of the 84 hospitalized patients referred for PEG, 72 were enrolled in a one-third observation (Group A) and two-thirds in a randomized trial (Groups B and C). Nasopharyngeal swabs were taken from a consecutive series of patients prior to PEG insertion. Based upon these results, they were classified into three groups: Group A, MRSA-negative (n = 24), Group B, MRSA-positive, but not eradicated (n = 24), Group C, MRSA-positive and eradicated with intranasal application of mupirocin, arbekacin inhalation, and oral sulfamethoxazole/trimethoprim (n = 24). The standard PEG pull-through insertion technique was performed on all 72 patients. All patients received prophylactic and concomitant antibiotics. Infections at the peristomal site were prospectively evaluated and defined as having at least two of the following conditions: peristomal erythema, induration, and purulent discharge. Bacterial culture using purulent discharge was performed. There was significant difference in the peristomal infection rates among the groups: Group A, 0% (0/0); Group B, 100% (24/24); Group C, 8% (2/24) (p < or = 0.0001). In Group C, nasopharyngeal decolonization of MRSA, which was achieved by the combination of intranasal mupirocin, arbekacin inhalation, and oral sulfamethoxazole/trimethoprim in all 24 patients, significantly reduced peristomal infections. Eighteen (16 in Group B and 2 in Group C) of these 26 infected patients had cellulitis and developed purulent discharge from which MRSA was isolated. Nasopharyngeal decolonization of MRSA can reduce peristomal infection shortly after the pull-through PEG insertion. MRSA appears to be a major pathogen in PEG peristomal infection while prophylactic and concomitant antibiotics are being used.

Modiolar Coiling, Electrical Thresholds, and Speech Perception after Cochlear Implantation Using the Nucleus Contour Advance Electrode with the Advance Off Stylet Technique

Perimodiolar electrode arrays were developed in an attempt to improve stimulation of specific neural populations and to decrease electrical thresholds, thereby decreasing power consumption. Postoperative radiographs show that coiling of the arrays is variable. Our previous study explored the relationship between the angle of coiling, threshold levels, and functional outcomes using the Nucleus Contour electrode array. This study compares coiling angle, electrical threshold levels, and speech perception measures with the Nucleus Contour Advance electrode array implanted using the new advance off stylet technique versus the Nucleus Contour electrode array implanted using the standard technique. Retrospective review. University medical center. Forty-two adults and children with normal cochlear anatomy implanted with the Nucleus CI24RCA electrode using the advance off stylet technique with at least 1-year follow-up. Therapeutic. Computer-aided radiographic analysis of perimodiolar electrode placement, electrical threshold measurements, and speech perception outcome measures at 1 year postimplantation. The degree of modiolar coiling was tighter using the new electrode and technique in comparison with standard insertion technique using the Nucleus Contour electrode array. The tighter coiling tended to result in higher electrical thresholds. Lower speech perception outcome measures tended to correlate with a higher degree of coiling. The Nucleus Contour Advance electrode array combined with the advance off stylet technique resulted in a more consistent perimodiolar position. However, the tighter coiling resulted in statistically significant increased electrical thresholds and decreased speech perception outcomes. This finding may be secondary to multiple factors, not just coiling angle.

An improved technique for gaining radial artery access in endovascular interventions

We present a simple technique to avoid time loss and potential dangerous maneuvers for catheterization of the radial artery in endovascular interventions. If any difficulties are encountered when advancing the guide wire after the arterial puncture using standard transradial kits, we found it useful to routinely use a 60-mm polyethylene radial pressure line catheter like the Leader Cath (Vygon, Ecquen, France), which is more flexible and less traumatic than short catheters and are usually available in the standard hydrophilic transradial kit. With the 20-gauge needle within the arterial lumen, it is sufficient to advance the guide wire 3 or 4 cm, followed by the insertion of the radial pressure line catheter for administering a vasodilator cocktail. The contrast injection through the catheter is safer than through the needle, and visualization of the underling problems may avoid any time loss and complications. The standard sheath insertion is facilitated by the pressure line catheter that acts as a dilator. This technique, especially when performing coronary or peripheral interventions in which large introducers are needed, may avoid potentially dangerous vascular complications and improve the success rate.

A Test to Detect Chest Tube Kinking

To determine whether the Mac-technique test can detect kinking of the chest tube upon thoracostomy tube placement. This was a prospective observational study that was conducted October 2000 through October 2001 in an urban Level 1 trauma center. There were 103 consecutive nonrandomized adult trauma patients who required immediate tube thoracostomy during their initial resuscitation who were entered into the study. The Mac-technique test was performed during standard tube thoracostomy insertion to the appropriate depth. The test involved grasping the external portion of the thoracostomy tube, turning it clockwise 180 degrees, and then releasing the tube. If the tube spontaneously spun back to its original position, the test was considered positive, and the tube was considered kinked. If the tube did not spontaneously spin back and stayed in position upon release, the test was considered negative. Regardless of the results of this test, the tube was secured, and a postprocedure chest radiograph was obtained. The criterion standard for determining a kinked chest tube was its appearance on this chest radiograph. A total of 103 chest tubes were placed by using the Mac-technique test. The test was positive in eight placements; four tubes were kinked on chest radiograph. The Mac-technique test was negative in 95 placements; four tubes were kinked on chest radiograph. The Mac technique had a sensitivity of 50% (95% confidence interval [CI] = 15.7% to 84.3%), a specificity of 95.8% (95% CI = 89.6% to 98.8%), a positive likelihood ratio of 11.9, a negative likelihood ratio of 0.52, and an odds ratio using Yates correction of 20.3 (95% CI = 4.1 to 102.1). On the basis of this study, a positive Mac-technique test is useful to detect chest tubes that are likely to be kinked after insertion and before securing.

Intrapartum Temperature Changes Following the, Intravenous Crystalloid Bolus for Epidural Analgesia

Objective: To assess the effect of the intravenous crystalloid bolus given before epidural analgesia on maternal temperature during labour. Multiple studies have demonstrated a hyperthermic trend in parturient women receiving epidural analgesia. This temperature rise may be affected by the pre-epidural intravenous crystalloid bolus.Methods: Intrapartum oral temperatures were recorded in 40 singleton parturient women immediately before and after an intravenous bolus of Ringer’s lactate solution (1L at room temperature [21 °C]) and at one hour after standardized insertion, of an epidural catheter for analgesia. Exclusion criteria included antibiotic administration, chorioamnionitis, and initial maternal temperature above 37.5°C. Group means were compared using the 2-tailed paired Student t test.Results: There was no significant trend towards a decrease in maternal temperature after the crystalloid bolus (mean change −0.07°C, P = 0.33). Similarly, there was no initial trend towards an increased maternal temperature after-epidural insertion mean change + 0.02°C, P > 0.7). Separate analyses using parity, body mass index and bolus duration as covariates showed that these variables did not affect maternal temperature changes (P>> 0.2).Conclusion: Our study indicates that intravenous infusion of a crystalloid bolus at room temperature before induction of epidural analgesia does not significantly decrease parturient temperature.

A Model for Cochlear Implant Electrode Insertion and Force Evaluation: Results with a New Electrode Design and Insertion Technique

This study has the specific aim of evaluating the insertion characteristics of a new cochlear implant electrode. Techniques for evaluation of fluoroscopic real time mechanical insertion dynamics, histologic electrode position and trauma results, hydraulic force, and mechanical insertion forces are presented. In addition, this study should serve to present a novel model for cochlear implant electrode insertion evaluations. Prospective analysis using a series of analytical techniques. All studies are conducted in fixed cadaveric temporal bones. Real time fluoroscopic insertion evaluations, histologic evaluations for trauma and electrode position in embedded bones, hydraulic measures, and mechanical intracochlear force measurements are conducted with a current and new electrode. The Contour Advance electrode provides a more reliable and less traumatic insertion when deployed with the Advance Off Stylet technique. This is largely because of a reduction in intracochlear outer wall force generation. Fluoroscopic and histologic analysis reveal a smooth insertion without reliance on cochlear outer wall contact. No hydraulic forces were detected when measured from the superior semicircular canal ampulla. The model used for this study provides valuable information to cochlear implant surgeons and design engineers. The Contour Advance electrode, inserted with the Advance Off Stylet technique, represents an improvement over the Contour electrode inserted with the standard insertion technique.

Controlling order circuity in pickup and delivery problems

This paper examines the effects of constraining order circuity during the course of a dynamic pickup and delivery routing algorithm. Order circuity, the ratio of actual to direct shipping distance, affects shipping performance metrics such as transit time and vehicle utilization. The paper begins by exploring the tradeoff between utilization and order circuity, and then describes the application of circuity controls within an algorithm implemented for automobile shipping. We found that circuity controls are more effective than standard least-cost insertion heuristics alone in producing efficient route solutions with lower frequency of anomalous order routings.

CONFORMAL MODULI AND b-c PICTURES FOR NSR STRINGS

We explore the geometry of superconformal moduli of the NSR superstring theory in order to construct the consistent sigma-model for NSR strings, free of picture-changing complications. The sigma-model generating functional is constructed by the integration over the bosonic and fermionic moduli, corresponding to insertions of the vertex operators in scattering amplitudes. While the integration over the supermoduli leads to the standard picture-changing insertions, the integration over the bosonic moduli results in the appearance of picture-changing operators for the b-c fermionic ghosts with the ghost number -1. Important example of the b-c ghost pictures involves the vertex operators in integrated and unintegrated forms. We obtain the BRST-invariant expressions for the b-c picture-changing operators for open and closed strings and study some of their properties. We also show that the superconformal moduli spaces of the NSR theory contain the global singularities, leading to the phenomenon of ghost-matter mixing and the appearance of nonperturbative D-brane creation operators.

Blue Ribbon Abstract Award: Standardization of the central venous catheter insertion process reduces catheter-associated bloodstream infections in a university hospital medical intensive care unit

ISSUE: Use of central venous catheters (CVC) has been associated with increased incidence of bloodstream infections (BSIs). We set out to decrease the rate of CVC-associated BSI (CVC-BSI) by implementing a multifaceted intervention that included provider education, a standardized insertion checklist, and real-time performance feedback. PROJECT: Our institution defines CVC-BSI using National Nosocomial Infections Surveillance (NNIS) system criteria. During the year prior to the intervention (October 2001 to September 2002), our 14-bed medical intensive care unit (MICU) had a CVC-BSI rate of 7.6/1000 central line days. Based upon published guidelines, a multidisciplinary team developed a mandatory online tutorial and examination for medical and nursing staff. At each CVC insertion or guidewire exchange, the bedside nurse completed a standardized checklist that identified evidence-based insertion behaviors. The checklists were scanned into a computerized database, allowing rapid data entry. Real-time performance feedback reports were generated, and the MICU staff and physicians were provided unit specific data at the start of each month and 3 weeks later to allow resident physicians, who rotate monthly, to review their data and adjust their practice as needed. This collaborative intervention was designed to be educational and not punitive in nature. RESULTS: Following implementation in October 2002, the intervention has been used for 701 CVC insertions. The CVC-BSI rate for lines impacted by this study decreased to a 2004 rate of 1.9/1000 central line days. There have been two periods of greater than 200 days each between CVC-BSI. Positive feedback from this intervention has led to its acceptance and continued use for more than 2 years. MICU is proud of the low BSI rate and works to maintain it. LESSONS LEARNED: Using a standardized intervention aimed at CVC insertion reduces CVC-BSI rates. Development of a successful program requires cooperation and buy-in from physicians as well as nursing staff to effect change. Use of a standardized form provides data for process improvement as well as documentation for the medical record. The observation checklist is available in the electronic medical record. Due to the continued success in the MICU, we started implementing the intervention in all critical care areas in 2004.

Total hip replacement in identical twins with Scheie Mucopolysaccharidosis.

Investigation performed at the Hospital for Special Surgery, New York, USA Scheie Syndrome is an autosomal recessive metabolic storage disease with distinct skeletal findings known as "dysostosis multiplex". This paper reports on identical twins with Scheie Syndrome who required total hip arthroplasty for early osteoarthritis of the hip. The surgical approach and exposure was particularly demanding due to the stiffness imposed by the soft tissues arising from infiltration of glycosaminoglycans. The small femoral head and acetabulum limited the diameter of the acetabular component and subsequently the prosthetic head diameter that could be safely utilized without compromising the thickness of the polyethylene liner. Twenty-two millimeter heads with a standard polyethylene insert were therefore utilized in the two arthroplasties performed in 1998 in the first twin, and a 28 mm head with a highly cross linked polyethylene liner, in the arthroplasty performed on the second twin in 2003. This is a relevant issue considering that these patients required an arthroplasty at a young age. Hip arthroplasty relieved pain, improved ambulation and provided a better range of motion in our two patients. There were no peri-operative complications. Long-term survivorship of total hip replacement in this population is not yet known. (Hip International 2005; 15: 55-8).

CT-guided multi-catheter insertion technique for partial breast brachytherapy: Reliable target coverage and dose homogeneity

Purpose To evaluate the feasibility and dosimetric reliability of a CT-guided method of catheter insertion for accelerated partial breast brachytherapy (APBB). Materials and methods From 1995 to 2002, 77 patients were treated with APBB using a multi-catheter low-dose-rate or high-dose-rate approach. Within that timeframe, 29 patients with early stage invasive breast cancer were treated with high-dose-rate partial breast brachytherapy and had CT scans of the brachytherapy implant available for analysis. Initially, catheter insertion was accomplished in the operating room at the time of lumpectomy using standard free-hand insertion techniques under fluoroscopic guidance and subsequent orthogonal film dosimetry. To improve the efficiency and quality of the technique, the procedure was moved to the departmental CT-simulation suite where the catheters were placed with CT guidance. Basic guidelines of needle insertion and implant construction were followed to assure appropriate intercatheter and interplanar spacing that allowed optimal dosimetric coverage of the target volume. Target volumes were delineated and a treatment plan generated using a 3D planning system (Varian Brachyvision). PTV 1 cm was defined as the lumpectomy cavity plus 1 cm and PTV 2 cm as the lumpectomy cavity plus 2 cm. Target coverage goals were set as delivery of 100% of the prescribed dose to >95% of PTV 1 cm and >90% of the dose to >90% of PTV 2 cm. Dose homogeneity index (DHI) was defined as (V150%–V100%/V100%) with a goal of achieving >0.75. Fifteen patients were treated using the initial method and 14 patients using the CT-guided technique. Targets were retrospectively entered in the initial group and dose volume histogram analysis completed on all patients. The ability of each technique to achieve the target coverage and homogeneity goals was compared. Results With the change from traditional techniques to a CT-guided technique, the percentage of patients satisfying all dosimetric goals increased from 42% to 93%. Mean dose coverage (defined as the percentage of PTV 2 cm receiving 90% of the prescribed dose) increased from 89% to 95% ( p = 0.007) and the mean DHI increased from 0.77 to 0.82 with the new technique ( p < 0.005). Conclusions Reproducible target coverage and dose homogeneity were achieved with CT-guided catheter insertion and 3D planning software. Catheters can be optimally placed with intraoperative CT evaluation and 3D planning software allows improved implant visualization resulting in optimized dosimetry. Improvements in target coverage and DHI may translate into optimized local control and improved cosmesis with a corresponding reduction in the risk of complications.

Practical Approach to Implanting Left Ventricular Pacing Leads for Cardiac Resynchronization

Our approach to implanting cardiac resynchronization therapy (CRT) devices combines an understanding of the anatomy of the failing heart and the coronary veins, standard pacing lead insertion skills, and techniques common to diagnostic cardiac catheterization and interventional cardiology. The method we have devised over the past 5 years has provided CRT safely and effectively to a large volume of compromised patients with congestive heart failure (CHF) and conduction system disease.

Total hip replacement in identical twins with Scheie Mucopolysaccharidosis

Investigation performed at the Hospital for Special Surgery, New York, USA Scheie Syndrome is an autosomal recessive metabolic storage disease with distinct skeletal findings known as "dysostosis multiplex". This paper reports on identical twins with Scheie Syndrome who required total hip arthroplasty for early osteoarthritis of the hip. The surgical approach and exposure was particularly demanding due to the stiffness imposed by the soft tissues arising from infiltration of glycosaminoglycans. The small femoral head and acetabulum limited the diameter of the acetabular component and subsequently the prosthetic head diameter that could be safely utilized without compromising the thickness of the polyethylene liner. Twenty-two millimeter heads with a standard polyethylene insert were therefore utilized in the two arthroplasties performed in 1998 in the first twin, and a 28 mm head with a highly cross linked polyethylene liner, in the arthroplasty performed on the second twin in 2003. This is a relevant issue considering that these patients required an arthroplasty at a young age. Hip arthroplasty relieved pain, improved ambulation and provided a better range of motion in our two patients. There were no peri-operative complications. Long-term survivorship of total hip replacement in this population is not yet known. (Hip International 2005; 15: 55-8).

The effect of tibial polyethylene insert design on range of motion*1Evaluation of in vivo knee kinematics by a computerized navigation system during total knee arthroplasty

Computer-assisted navigation for total knee arthroplasty offers the unique opportunity to assess in vivo knee kinematics during surgery and implement changes whenever appropriate. Using a computerized navigation system, the effect of 2 tibial polyethylene insert designs on knee kinematics in general and knee range of motion (ROM) in particular was evaluated in 37 knee arthroplasties in 30 patients. The Scorpioflex tibial insert was found to provide a significant increase in mean extension, mean flexion, and overall ROM of the knee compared with the standard tibial insert (P<.005) without affecting knee ligamentous balance. Navigation is a very effective and useful tool for intraoperative assessment of knee kinematics and accurate recording of ROM. Based on the information obtained from the navigation software, the surgeon can implement changes in selection of the knee components with beneficial effects in knee kinematics in general and knee ROM in particular. This may, in turn, translate to better clinical outcome of the knee arthroplasty.

The effect of tibial polyethylene insert design on range of motion: Evaluation of in vivo knee kinematics by a computerized navigation system during total knee arthroplasty

Computer-assisted navigation for total knee arthroplasty offers the unique opportunity to assess in vivo knee kinematics during surgery and implement changes whenever appropriate. Using a computerized navigation system, the effect of 2 tibial polyethylene insert designs on knee kinematics in general and knee range of motion (ROM) in particular was evaluated in 37 knee arthroplasties in 30 patients. The Scorpioflex tibial insert was found to provide a significant increase in mean extension, mean flexion, and overall ROM of the knee compared with the standard tibial insert ( P<.005) without affecting knee ligamentous balance. Navigation is a very effective and useful tool for intraoperative assessment of knee kinematics and accurate recording of ROM. Based on the information obtained from the navigation software, the surgeon can implement changes in selection of the knee components with beneficial effects in knee kinematics in general and knee ROM in particular. This may, in turn, translate to better clinical outcome of the knee arthroplasty.