Knee Implant Loosening Detection: A Vibration Analysis Investigation

Knee implant loosening is mainly caused by the weakness of the prosthesis-bone interface and is the main reason for surgical revisions. However, pre-operative diagnosis is difficult due to lack of accurate tests. In this study, we developed a vibration-based system to detect the loosening of the tibial implant of an instrumented knee prosthesis. The proposed system includes an instrumented vibrator for transcutaneous stimulation of the bone in a repeatable manner, and accelerometer sensors integrated into the implants to measure the propagated vibration. A coherence-based detection technique was proposed to distinguish the loosened implants from the secure ones. Fourteen ex vivo lower limbs were used, on which the knee prosthesis was implanted, and harmonic-forced vibration was applied on the tibia. The input–output coherence measure provided 92.26% accuracy, a high sensitivity (91.67%) and specificity (92.86%). This technique was benchmarked against power spectrum based analysis of the propagated vibration to the implant. In particular, loosening detection based on new peak appearance, peak shift, and peak flattening in power spectra showed inferior performance to the proposed coherence-based technique. As such, application of vibration on our instrumented knee prosthesis together with input–output coherence analysis enabled us to distinguish the secure from loose implants.     

Does Robotic Roux-en-Y Gastric Bypass Provide Outcome Advantages over Standard Laparoscopic Approaches?

Objective

The aim was to compare clinical outcomes of patients treated with totally robotic Roux-en-Y gastric bypass (TRRYGB) with those treated with the different laparoscopic Roux-en-Y gastric bypass (LRYGB) techniques.

Summary Background Data

The clinical benefit of the robotic approach to bariatric surgery compared to the standard laparoscopic approach is unclear. There are no studies directly comparing outcomes of TRRYGB with different LRYGB techniques.

Methods

Outcomes of 578 obese patients who underwent RYGB between 2011 and 2014 at an academic center were assessed. Multivariable analysis and propensity matching were used for comparing TRRYGB to different LRYGB techniques, including 21-mm EEA circular-stapled gastrojejunal anastomosis (GJA, LRYGB-21CS), linear-stapled GJA (LRYGB-LS), and hand-sewn GJA (LRYGB-HS).

Results

The TRRYGB technique required a longer mean operative time compared to the other groups, respectively 204?±?46 vs. 139?±?30 min (LRYGB-21CS), 206?±?37 vs. 158?±?30 min (LRYGB-LS), and 210?±?36 vs. 167?±?30 min (LRYGB-HS). TRRYGB experienced a lower stricture rate (2 vs. 17%, P?=?0.003), shorter hospital stay (2.6?±?1.2 vs. 4.3?±?5.5 days, P?=?0.008), and lower readmission rate (12 vs. 28%, P?=?0.009). No significant differences in outcomes were observed when comparing RRYGB to LRYGB-LS or LRYGB-HS.

Conclusions

TRRYGB increases operative time compared to all LRYGB techniques. TRRYGB was superior to LRYGB-21CS in terms of significantly shorter hospital stay, lower readmission rate, and less frequent GJA stricture formation. TRRYGB provides no clinical advantages over the LRYGB-LS and LRYGB-HS techniques.

     

Bariatric Surgery in Patients with Cirrhosis and Portal Hypertension

Introduction

Studies on bariatric patients with cirrhosis and portal hypertension are limited. The aim of this study was to review our experience in cirrhotic patients with portal hypertension who had bariatric surgery.

Method

All cirrhotic patients with portal hypertension who underwent laparoscopic bariatric surgery, from 2007 to 2017, were retrospectively reviewed.

Results

Thirteen patients were included; eight (62%) were female. The median age was 54 years (interquartile range, IQR 49–60) and median BMI was 48 kg/m² (IQR 43–55). Portal hypertension was diagnosed based on endoscopy (n?=?5), imaging studies (n?=?3), intraoperative increased collateral circulation (n?=?2), and endoscopy and imaging studies (n?=?3). The bariatric procedures included sleeve gastrectomy (n?=?10, 77%) and Roux-en-Y gastric bypass (n?=?3, 23%). The median length of hospital stay was 3 days (IQR 2–4). Three 30-day complications occurred including wound infection (n?=?1), intra-abdominal hematoma (n?=?1), and subcutaneous hematoma (n?=?1). No intraoperative or 30-day mortalities. There were 11 patients (85%) at 1-year follow-up and 9 patients (69%) at 2-year follow-up. At 2 years, the median percentage of excess weight loss (EWL) and total weight loss (TWL) were 49 and 25%, respectively. There was significant improvement in diabetes (100%), dyslipidemia (100%), and hypertension (50%) at 2 years after surgery.

Conclusion

Bariatric surgery in selected cirrhotic patients with portal hypertension is relatively safe and effective.

     

Ipsilateral talar and calcaneal fractures: A retrospective review of complications and sequelae

Background

Ipsilateral talar and calcaneal fractures represent a rare combination injury that has only recently been reported in the literature with small case series.

Objective

To identify the commonly observed fracture patterns, complications, and outcomes of a consecutive series of patients with ipsilateral talar and calcaneal fractures.

Methods

Forty-five cases of ipsilateral talus and calcanal fractures were identified from an orthopaedic trauma registry at a University-based, level I trauma center for retrospective review.

Main outcome measurements

Post-operative complications, the need for secondary surgery, and the visual analogus pain score.

Results

Five patients were treated with an early below knee amputation (BKA). Five patients were treated with a primary subtalar arthrodesis. Twenty-eight of the 35 patients who did not undergo early BKA or primary subtalar arthrodesis developed subtalar arthritis. Five patients had deep wound complications. Four patients had talar body collapse from avascular necrosis. There were 13 open fractures of which 8 resulted in an eventual BKA. The mean visual analogus pain score for the patient population was 4.0.

Conclusion

The combination of ipsilateral talar and calcaneal fractures represents a severe injury pattern that is associated with significant morbidity. Subtalar arthritis was a common finding regardless of treatment. Open fractures frequently resulted in a below knee amputation.     

Effect of extremely low frequency magnetic field on antioxidant activity in plasma and red blood cells in spot welders

Objective  The purpose of this study was to determine a possible relation between exposure to extremely low frequency magnetic field (ELF-MF) and the human antioxidant activity. Methods  The total serum antioxidant status (TAS), red blood cells (RBCs) glutathione peroxidase (GPX) and superoxide dismutase (SOD) were measured in 46 spot welders who were occupationally exposed to ELF-MF (magnetic field strength = 8.8–84 microTesla (μT), frequency = 50 Hertz (Hz) and electric field strength = 20–133 V/m). The results were compared with a nonexposed ELF-MF control group. The correlation between magnetic field strength and antioxidant activity in RBCs and plasma was then assessed. Results  No significant differences in TAS levels were observed (P value = 0.065). However, in RBCs of exposed group, a significant decrease in SOD and GPX activities was observed (P value = 0.001 and 0.003, respectively). This decrease was measured as 22 and 12.3%, respectively. Furthermore, a significant negative correlation between SOD/GPX activities and magnetic field intensity was observed (coefficients of SOD: −0.625, significance: 0.0001 and coefficients of GPX: −0.348, significance: 0.018). Conclusion  The results of this study indicate that ELF-MF could influence the RBC antioxidant activity and might act as an oxidative stressor. Intracellular antioxidant enzymes such as SOD and GPX were found to be the most important markers involving in this process. The influence of magnetic field on the antioxidant activity of RBCs might occur even at the recommended levels of exposure.     

Mid-diaphyseal fibular fractures with syndesmotic disruption: should we plate the fibula?

BACKGROUND: The treatment of mid-diaphyseal fibula fractures with syndesmotic disruption is controversial. The purpose of this study was to compare the biomechanical properties of 2 fixation constructs. MATERIALS AND METHODS: Eight pairs of human cadaveric legs were divided into two groups, both of which had midshaft fibular osteotomies and disruption of all ligamentous support up to the osteotomy level. In Group I, the left legs were fixed with only a 3.5-mm tricortical syndesmotic screw. In Group II, the right legs received this syndesmotic fixation in addition to plating of the fibula. Rotational stability was tested on each ankle in the intact, repaired, and post-cyclical load conditions. Each specimen was ultimately tested to failure in external rotation. RESULTS: The rotational stability, load to failure, and stiffness were all found to be significantly higher with the plate and syndesmotic fixation repair technique (Group II) than with the syndesmotic fixation only technique (Group I). Furthermore, fixation in Group II improved rotational stability both before and after cyclic loading. CONCLUSION: Improved biomechanical properties were found with fibular plating in addition to a syndesmotic screw in a midshaft fibular fracture model with syndesmotic and deltoid injury. CLINICAL RELEVANCE: This information may be helpful in the decision-making process to optimally treat patients with this fracture pattern.     

Evaluation of IOL power calculation with the Kane formula for pediatric cataract surgery

Graefe's Archive for Clinical and Experimental Ophthalmology - To assess the accuracy of the Kane formula for intraocular lens (IOL) power calculation in the pediatric population. The charts of...     

Cathepsin B inhibition limits bone metastasis in breast cancer

Metastasis to bone is a major cause of morbidity in breast cancer patients, emphasizing the importance of identifying molecular drivers of bone metastasis for new therapeutic targets. The endogenous cysteine cathepsin inhibitor stefin A is a suppressor of breast cancer metastasis to bone that is coexpressed with cathepsin B in bone metastases. In this study, we used the immunocompetent 4T1.2 model of breast cancer which exhibits spontaneous bone metastasis to evaluate the function and therapeutic targeting potential of cathepsin B in this setting of advanced disease. Cathepsin B abundancy in the model mimicked human disease, both at the level of primary tumors and matched spinal metastases. RNA interference-mediated knockdown of cathepsin B in tumor cells reduced collagen I degradation in vitro and bone metastasis in vivo. Similarly, intraperitoneal administration of the highly selective cathepsin B inhibitor CA-074 reduced metastasis in tumor-bearing animals, a reduction that was not reproduced by the broad spectrum cysteine cathepsin inhibitor JPM-OEt. Notably, metastasis suppression by CA-074 was maintained in a late treatment setting, pointing to a role in metastatic outgrowth. Together, our findings established a prometastatic role for cathepsin B in distant metastasis and illustrated the therapeutic benefits of its selective inhibition in vivo.