Development and psychometric evaluation of a cardiovascular risk and disease management knowledge assessment tool.

PURPOSE: This article describes the systematic construction and psychometric analysis of a knowledge assessment instrument for phase II cardiac rehabilitation (CR) patients measuring risk modification disease management knowledge and behavioral outcomes derived from national standards relevant to secondary prevention and management of cardiovascular disease. METHODS: First, using adult curriculum based on disease-specific learning outcomes and competencies, a systematic test item development process was completed by clinical staff. Second, a panel of educational and clinical experts used an iterative process to identify test content domain and arrive at consensus in selecting items meeting criteria. Third, the resulting 31-question instrument, the Cardiac Knowledge Assessment Tool (CKAT), was piloted in CR patients to ensure use of application. Validity and reliability analyses were performed on 3638 adults before test administrations with additional focused analyses on 1999 individuals completing both pretreatment and posttreatment administrations within 6 months. RESULTS: Evidence of CKAT content validity was substantiated, with 85% agreement among content experts. Evidence of construct validity was demonstrated via factor analysis identifying key underlying factors. Estimates of internal consistency, for example, Cronbach's α = .852 and Spearman-Brown split-half reliability = 0.817 on pretesting, support test reliability. Item analysis, using point biserial correlation, measured relationships between performance on single items and total score (P < .01). Analyses using item difficulty and item discrimination indices further verified item stability and validity of the CKAT. CONCLUSIONS: A knowledge instrument specifically designed for an adult CR population was systematically developed and tested in a large representative patient population, satisfying psychometric parameters, including validity and reliability.

Diminished suture strength after robotic needle driver manipulation.

Robot-assisted minimally invasive surgery has become a routine surgical option for the treatment of prostate cancer. Despite its technical advancements, the da Vinci(®) Surgical System still lacks haptic feedback to the surgeon, resulting in a maximally applied compressive force by the robotic needle driver during every grasping maneuver. Without this perceptional sense of touch and grip control, repetitive robotic needle driver manipulation may unknowingly lead to irreparable damage to fine sutures used during delicate anastomotic repairs. For robotic prostatectomy, any such loss of integrity can potentially lead to premature breakdown of the urethrovesical anastomosis and urine extravasation, especially important for a less-than-perfectly fashioned anastomotic repair. Although it has already been established that overhandling of sutures using handheld laparoscopic instruments can lead to reduced suture strength, it has not been established to what extent this may occur after robotic surgical procedures. We present analytical data and analyses concerning the failure strength of fine sutures commonly used for urethrovesical anastomotic repair during robotic prostatectomy, after repetitive robotic needle driver manipulation. When compared with noncompromised monofilament suture controls, the average maximal failure force after repetitive robotic manipulation was significantly reduced by 35% (p < 0.0001). Similarly, the average maximal failure force of braided sutures was significantly reduced after repetitive robotic manipulation by 3% (p = 0.009). This work demonstrates that significant reductions in monofilament and braided suture strength integrity can occur after customary repetitive manipulation by robotic needle drivers in an ex vivo model, with further research warranted in the in vivo setting.

Kinematics of the posterior cruciate ligament/posterolateral corner-injured knee after reconstruction by single- and double-bundle intra-articular grafts.

BACKGROUND: Single- and double-bundle reconstructions have been proposed for the knee after combined posterior cruciate ligament/posterolateral corner injuries. HYPOTHESIS: The double-bundle posterior cruciate ligament reconstruction is superior to the single-bundle posterior cruciate ligament reconstruction with regard to restoration of normal knee kinematics to the posterior cruciate ligament/posterolateral corner-sectioned knee. STUDY DESIGN: Controlled laboratory study. METHODS: Kinematics of 8 fresh-frozen, cadaveric human knees were determined in the following conditions: intact, sectioned posterior cruciate ligament/posterolateral corner, single anterolateral bundle posterior cruciate reconstruction, and double-bundle posterior cruciate reconstruction. RESULTS: The sectioned knee demonstrated a posterior shift of the tibial neutral position and the abnormal posterior, varus, and external rotation laxities used clinically to define a combined posterior cruciate ligament/posterolateral corner injury. Both reconstructions restored the posterior laxity to levels that were not statistically different from those seen in the intact knee, but the double-bundle reconstruction more closely mimicked the posterior laxity profile of the intact knee, having statistically lower posterior laxities than did the single-bundle reconstruction at 30 degrees, 60 degrees, and 90 degrees of flexion (P < .05, analysis of variance, HSD test). The resting position of the tibia after double-bundle reconstruction trended to be anteriorly subluxated relative to its position for the intact knee at flexion angles of 30 degrees and greater (P <.05, paired t test). Neither technique corrected the abnormal varus or external rotation laxities. CONCLUSION: With either single- or double-bundle reconstructions, additional posterolateral reconstruction is recommended to correct the external rotation laxity. CLINICAL RELEVANCE: Knowledge of the kinematics of the combined posterior cruciate ligament/posterolateral corner-injured knee is important in the proper diagnosis of the injury and in the selection of the appropriate surgical reconstruction.

Novel method used to test pullout parameters of different nephrostomy catheters.

PURPOSE: To present a novel in-vitro pig model for testing the design and function of different internal catheter constructs, along with the resulting exit wound resulting from removal. MATERIALS AND METHODS: We compared the pullout parameters of two nephrostomy catheters that differ only in their internal loop design. RESULTS: Greater force, work, and displacement are necessary to extricate catheters with a double loop without increasing exit-wound size. CONCLUSION: Although the differences were not statistically significant, results from this model have potential clinical implications that may prompt further design modifications and prototype development to improve the retention of catheters in the kidney, thus reducing patient discomfort and costs associated with repeated catheter placement.

Measuring flexion in knee arthroplasty patients.

Flexion following total knee arthroplasty can be visually estimated, measured with a goniometer placed against the patient's leg, or measured from a lateral radiograph of the flexed knee. Three examiners, in a blinded fashion, estimated the degree of maximal knee flexion and measured the flexion with a goniometer for 27 knees in 16 patients. A lateral knee radiograph then was taken and the flexion angle was measured from the radiograph by 2 different methods. Although interobserver and intraobserver correlation coefficients were high (0.79 and 0.92), 45% of the visual estimates and 22% of the goniometer measurements differed by 5 degrees or greater from the radiographic measurements. These differences increased as the flexion angle increased. Body mass index did not affect the accuracy of the estimates or goniometer measurements.