Stimulation of the mechanosensitive ion channel, Piezo1 promotes bone anabolism and SNPs in the Piezo1 locus are associated with changes in fracture risk. Osteocytes function as critical regulators of bone homeostasis by sensing mechanical signals. The current study used a human, cell-based physiological, 3D in vitro model of bone to determine whether loading of osteocytes in vitro results in upregulation of the Piezo1 pathway. Human Y201 MSCs, embedded in type I collagen gels and differentiated to osteocytes for 7-days, were subjected to pathophysiological load (5000 µstrain, 10Hz, 5 mins; n=6) with unloaded cells as controls (n=4). RNA was extracted 1-hr post load and assessed by RNAseq analysis. To mimic mechanical load and activate Piezo1, cells were differentiated to osteocytes for 13 days and treated ± Yoda1 (5µM, 2- and 24-hs, n=4); vehicle treated cells served as controls (n=4). RNA was subjected to RT-qPCR and data normalised to the housekeeping gene, YWHAZ. Media was analysed for IL6 release by ELISA. Mechanical load upregulated Piezo1 gene expression (16.5-fold, p<0.001) and expression of the transcription factor NFATc1, and matricellular protein CYR61, known regulators of Piezo1 mechanotransduction (3-fold; p= 5.0E-5 and 6.8-fold; p= 6.0E-5, respectively). After 2-hrs, Yoda1 increased the expression of the early mechanical response gene, cFOS (11-fold; p=0.021), mean Piezo1 expression (2.3-fold) and IL-6 expression (103-fold, p<0.001). Yoda1 increased the release of IL6 protein after 24 hours (7.5-fold, p=0.001). This study confirms Piezo1 as an important mechanosensor in osteocytes. Piezo1 activation mediated an increase in IL6, a cytokine that drives inflammation and bone resorption providing a direct link between mechanical activation of Piezo1, bone remodeling and inflammation, which may contribute to mechanically induced joint degeneration in diseases such as osteoarthritis. Mechanistically, we hypothesize this may occur through promoting Ca2+ influx and activation of the NFATc1 signaling pathway.
Proper positioning of the acetabular cup deters dislocation after total hip arthroplasty (THA) and is therefore a key focus for orthopedic surgeons. The concept of a safe zone for acetabular component placement was first characterized by Lewinnek For any figures or tables, please contact the authors directly.
Exparel (Pacira Pharmaceuticals, Parsippany, NJ, USA) is a long-acting liposomal Bupivacaine extended release compound that can be used as peri-articular injection (PAI) or regional nerve block. The purpose of this study was to compare the post-operative analgesic efficacy of Exparel as a single administration adductor canal block (ACB) varsus PAI. From May 2016 to June of 2017, 70 patients with primary knee osteoarthritis undergoing unilateral knee replacement were prospectively randomized into two cohorts: 1) PAI (Exparel 266 mg (20 ml vial) with 20 ml of 0.5% bupivacaine HCl, and normal saline to a total volume of 120 ml); 2) ACB (Subsartorial saphenous nerve using Exparel 266 mg in 20 ml vial). All patents underwent spinal anesthesia with comprehensive pre-emptive and postoperative multimodal pain protocol. All opioids given were converted to morphine equivalents. Pain was recorded at 4 – 12 hrs (day of surgery), post-operative day (POD) 1, 2, and 3 after surgery.Background
Methods
While tranexamic acid (TXA) has been well shown to reduce blood loss after joint replacement surgery, little is known regarding its effectiveness in obese patients. The aim of this study was to evaluate the effect of TXA on packed red blood cell (PRBC) blood transfusion rates and change in hemoglobin (HGB) and hematocrit (HCT) for obese patients undergoing joint replacement at our institution. Between January and December 2014, 117 consecutive primary joint replacements (THA n=23; TKA n=94) were performed in obese patients (BMI ≥ 30kg/m2) by two surgeons. Medical records were reviewed and identified that TXA was utilized in 45 (38.5%) arthroplasties. TXA was given intravenously (IV) in two doses: (1) one gram prior to incision and (2) one gram at the time of femoral preparation in THA or prior to cementation in TKA. Topical TXA was utilized in cases where IV TXA was contraindicated. PRBC transfusion rates, changes in HBG and HCT, and occurrence of thrombolytic events were recorded from hospital records.Background
Material and methods
There has not been a comparison of patients and outcomes between two separate countries for any knee prosthesis. This study compares total knee replacement outcomes between an Indonesian and American cohort. We aim to compare the clinical results between two different hospitals in two different countries using post-operative range of motion as the primary clinical result. 177 Indonesian RPF TKR patients were compared to 84 American patients. Demographics, patient recorded outcomes scores (KSS, PAQ, WOMAC), flexion, and component size were compared between the groups. Standard t-test was used to compare the variables between the two countries and regression analysis adjusting for age, BMI, length of follow-up, sex, preoperative WOMAC and PAQ score, preoperative KSS knee score, preoperative KSS function score, and preoperative UCLA was used to compare outcomes.Introduction
Materials and Methods
Several studies have shown that functional outcomes are similar regardless of being discharged directly to home or to a rehabilitation center after total knee arthroplasty (TKA). Therefore, we sought to determine if there is a difference in patient care or patient satisfaction for patients discharged to in-patient rehabilitation or home-based rehabilitation. Between February and May of 2015, one hundred and seventy one consecutive patients were prospective identified after undergoing TKA by one of three surgeons. At an average of six-weeks post TKA, all patients were asked a patient administered questionnaire to determine if diagnostic testing (ultrasounds, or x-rays) or blood transfusions were performed during the first-six weeks at either home (n=86) or a rehab (n=85) facility.Introduction
Materials and Methods
The advent of ambulatory total joint replacements has called for measures to reduce postoperative length of stay, while improving patient function and postoperative satisfaction. This prospective, randomized trial evaluated the efficacy of one-on-one preoperative physical therapy (PT) education with a supplemental web-based PT web-portal on discharge disposition, postoperative function and patient satisfaction after total joint replacement. Between February and June 2015, 126 patients underwent unilateral total knee (n=63) or total hip arthroplasty (n=63). All patients attended a group preoperative education (preopEd) class [standard of care] and were subsequently randomized into two groups. One group received no further education as per the standard of care [control; TKA= 31; THA=32] and the other received an in-person one-on-one preoperative PT education session (preopPTEd) as well as access to a web-portal during the postoperative period [experimental; TKA=32; THA=31]. Discharge disposition was attained from hospital records. Patient satisfaction and WOMAC scores were evaluated by a series of patient administered questionnaires.Introduction
Materials & Methods
Patient-specific or “custom” total knee replacements have been designed to fit the arthritic knee in primary total knee arthroplasty (TKA) better than “off-the-shelf” implants. Using computer technology, patient-specific cutting-blocks and custom-made implants are created to more accurately fit the contour of the knee and reproduce the anatomic J-curve with the hope of providing a better functional outcome. This retrospective, matched-pair study evaluates manipulation under anesthesia (MUA) rates in cemented patient-specific cruciate-retaining (PSCR) TKA compared to that in both cemented posterior-stabilized (PS) and non-cemented cruciate-retaining rotating-platform (NC CR RP) TKA.Objective:
Purpose:
