A vibration sensor approach to detect intra-articular needle tip placement in the knee joint: a proof-of-concept study.

BACKGROUND: Intra-articular injection in the dry knee joint is technically challenging particularly for the beginners. The aim of this study was to investigate the possible use of the vibration sensor to detect if the needle tip was at the knee intra-articular position by characterizing the frequency component of the vibration signal during empty syringe air injection. METHODS: Two milliliters of air were injected supero-laterally at extra- and intra-articular positions of a cadaveric knee joint, using needles of size 18, 21 and 24 gauge (G). Ultrasonography was used to confirm the positions of needle tip. A piezoelectric accelerometer was mounted medially on the knee joint to collect the vibration signals which were analyzed to characterize the frequency components of the signals during injections. RESULTS: The vibration frequency band power in the range of 500-1500 Hz was visually observed to potentially localize the needle tip placement during air injection whether they were at the knee extra-articular or intra-articular positions, as demonstrated by the higher band power (over - 40 dB or dB) for all the needle sizes. The differences of frequency band power between extra- and intra-articular positions were 18.1 dB, 26.4 dB and 39.2 dB for the needle size 18G, 21G and 24G respectively. The largest difference in spectral power was found in the smallest needle diameter (24G). CONCLUSIONS: A vibration sensor approach was preliminarily proved to distinguish the intra-articular from extra-articular needle placement in the knee joint. This study demonstrated a possible implementation of an alternative electronic device based on this technique to detect the intra-articular knee injection.

Resurfacing in a Posterior-Stabilized Total Knee Arthroplasty Reduces Patellar Crepitus Complication: A Randomized, Controlled Trial.

BACKGROUND: Patellar crepitus (PC) is a common complication after total knee arthroplasty (TKA) using a posterior-stabilized (PS) prosthesis. While numerous factors have been associated with PC development after PS-TKA, patellar resurfacing (PR) which directly impacts the patellofemoral joint kinematics has been underinvestigated. A prospective, randomized, controlled trial was conducted to (1) compare the PC incidence in PR and non-PR PS-TKA, (2) determine the time of PC presentation in PS-TKA, (3) identify radiographic parameters associated with PC, and (4) compare clinical outcomes of patients with and without PR. METHODS: A total of 84 patients who underwent unilateral TKA using the Legion PS Total Knee System were randomized into PR group or non-PR group. PC incidence, time of PC presentation, radiographic parameters associated with PC development, and clinical outcomes were evaluated at 3 months, 6 months, 9 months, and 1 year postoperatively. RESULTS: PC occurred significantly more in the non-PR group (23.1% vs 7.3%, P = .048). Time of PC presentation in both groups was not different. Anterior knee pain was found in 16.7% of crepitus patients, and none required any surgical procedure. The non-PR knees had significant decreases in patellar shift index, patellar displacement, Insall-Salvati ratio, and patellar component height and increase in change in posterior femoral offset. Oxford and patellar scores were significantly better in the PR group at 9 months and 1 year. CONCLUSION: Given higher PC incidence and several worse clinical outcomes in the non-PR, we recommend resurfacing during PS-TKA with this knee system to avoid PC development.

Probing the origins of 17ß-hydroxysteroid dehydrogenase type 1 inhibitory activity via QSAR and molecular docking.

It is generally known that proliferation of human breast cancer cells is stimulated by excess estrogen namely 17ß-estradiol. Therefore, reduction of 17ß-estradiol production by inhibiting 17ß-hydroxysteroid dehydrogenase type 1 (17ß-HSD1) is an interesting route for breast cancer treatment particularly during adjuvant therapy. This study investigated the structure-activity relationship of 17ß-HSD1 inhibitors as to gain insights and understanding on the origins of 17ß-HSD1 inhibitory activities. To meet this goal, multiple linear regression model was constructed and correspondingly the results revealed good predictivity (N = 31, R(2) = 0.9438, Q(2) = 0.8530). The model suggested that low molecular weight and energy were preferred as 17ß-HSD1 inhibitors. Additionally, high molecular flexibility and high number of hydrogen bond donors were also shown to be important that is in correspondence to previously reported pharmacophore model of 17ß-HSD1 inhibitors. Furthermore, molecular docking of inhibitors to 17ß-HSD1 followed by anchor analysis suggested that three different pockets comprising of hydrogen bonding sites 1 and 2 as well as van der Waals contacts contributed to protein-ligand interactions. Post-docking analysis of potent compound 9 with 17ß-HSD1 suggested that the binding modality was similar to the binding of substrate (i.e. estradiol) and its analog (i.e. equilin). Such information is useful in guiding the further design of novel and robust 17ß-HSD1 inhibitors.

QSAR study of anti-prion activity of 2-aminothiazoles.

2-aminothiazoles is a class of compounds capable of treating life-threatening prion diseases. QSAR studies on a set of forty-seven 2-aminothiazole derivatives possessing anti-prion activity were performed using multivariate analysis, which comprised of multiple linear regression (MLR), artificial neural network (ANN) and support vector machine (SVM). The results indicated that MLR afforded reasonable performance with a correlation coefficient (r) and root mean squared error (RMSE) of 0.9073 and 0.2977, respectively, as obtained from leave-one-out cross-validation (LOO-CV). More sophisticated learning methods such as SVM provided models with the highest accuracy with r and RMSE of 0.9471 and 0.2264, respectively, while ANN gave reasonable performance with r and RMSE of 0.9023 and 0.3043, respectively, as obtained LOO-CV calculations. Descriptor analysis from the regression coefficients of the MLR model suggested that compounds should be asymmetrical molecule with low propensity to form hydrogen bonds and high frequency of N content at topological distance 02 in order to provide good activities. Insights from QSAR studies is anticipated to be useful in the design of novel derivatives based on the 2-aminothiazole scaffold as potent therapeutic agents against prion diseases.