Assessing joint function following trauma and its inter-relation with degenerative changes requires an understanding of the normal state of structural loading in the joint. Very few studies have attempted to reproduce joint specific in vivo motions in vitro to quantify the actual loads carried by different tissues within the knee joint. The most significant challenge in this area is the very high sensitivity of the loads in joint structures to motion reproduction accuracy. A novel testing platform for assessing knee joint mechanics is described, comprised of a highly accurate (0.3 ± 0.1 mm, 0.3 ± 0.1°) six-degree-of-freedom (6-DOF) instrumented spatial linkage (ISL) for in vivo joint kinematic assessments and a unique 6-DOF parallel robotic manipulator. A position feedback system (ISL and position controller) is used for accurate reproduction of in vivo joint motions and estimation of "in situ" joint/tissue loads. The parallel robotic manipulator provides excellent stiffness and repeatability in reproducing physiological motions in 6-DOF, compared to the commonly used serial robots. The position feedback system provides real-time feedback data to the robot to reproduce in vivo motions and significantly enhances motion reproduction accuracy by adjusting for robot end-effector movements. Using this combined robot-ISL system, in vivo motions can be reproduced in vitro with very high accuracy (0.1 mm, 0.1°). Our results indicate that this level of accuracy is essential for meaningful estimation of tissue loads during gait. Using this novel testing platform, we have determined the normal load-carrying characteristics of different tissues within the ovine knee joint. The application of this testing system will continue to increase our understanding of normal and pathological joint states.
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http://dx.doi.org/10.1007/s10439-014-0985-9 | DOI Listing |
J Orthop
July 2025
University of Louisville, Department of Orthopaedic Surgery, United States.
Background: Traditionally, total joint arthroplasty has been performed as an inpatient procedure, sometimes requiring a hospital stay of a few days. However, outpatient total joints have gained popularity in recent years. The purpose of this study is to compare patient outcomes following an outpatient total knee arthroplasty (TKA) or a total hip arthroplasty (THA) in a hospital setting versus an ambulatory surgical center.
View Article and Find Full Text PDFJ Orthop
July 2025
Department of Orthopaedic Surgery, St. Luke's University Health Network, Bethlehem, PA, USA.
Background: Tranexamic acid (TXA) use has become the gold standard in total joint arthroplasty to limit intraoperative blood loss and transfusion rates. More recently, the indications for TXA have expanded to knee and shoulder arthroscopy with promising early results. However, the effectiveness of TXA during arthroscopic rotator cuff repair (RCR) is unclear.
View Article and Find Full Text PDFCureus
December 2024
Department of Health Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, JPN.
Purpose The infrapatellar fat pad (IFP) has the lowest pain threshold among all knee joint components and causes anterior knee pain after knee arthroplasty. It has been reported that selective muscle atrophy of the vastus medialis (VM) and fibrosis of the IFP may develop following knee joint surgery. Ultrasound enables visualization of IFP deformation (A1) from within the joint to the proximal area in response to muscle contraction, and this may be helpful in developing preventive and therapeutic strategies for IFP fibrosis.
View Article and Find Full Text PDFOrthop J Sports Med
January 2025
Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
Background: Understanding the factors associated with poor recovery over time after anterior cruciate ligament reconstruction (ACLR) helps clinicians identify patients who are at risk and targets for an intervention.
Purpose: To determine the factors associated with improvement in subjective knee function from 6 to 12 months after ACLR.
Study Design: Case-control study; Level of evidence, 3.
Knee Surg Sports Traumatol Arthrosc
January 2025
Department of Joint Surgery and Sports Medicine, Graduate School of Medical and Dental Sciences, Institute of Science Tokyo, Tokyo, Japan.
Purpose: This study aimed to investigate whether combining the analysis of different magnetic resonance imaging (MRI) signs enhances the diagnostic accuracy of lateral meniscus posterior root tears (LMPRTs) in patients with anterior cruciate ligament (ACL) injuries. We hypothesised that analysing the cleft, ghost and truncated triangle signs and lateral meniscus extrusion (LME) measurement together would improve the preoperative MRI-based diagnosis of LMPRTs.
Methods: This retrospective study used prospectively collected registry data from two academic centres, including patients undergoing primary or revision ACL reconstruction (ACLR) and LMPRT repair.
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