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Joint Stiffness (joint + stiffness)
Selected AbstractsCombined effect of strength & sheet thickness on fatigue behaviour of resistance spot welded jointFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 9 2010S. GHOSH ABSTRACT Fatigue performance of spot welded lap shear joint is primarily dependent on weld nugget size, sheet thickness and corresponding joint stiffness. Two automotive steel sheets having higher strength lower thickness and lower strength higher thickness are resistance spot welded with established optimum welding condition. The tensile-shear strength and fatigue strength of lap shear joint of the two automotive steel sheets are determined and compared. Experimental fatigue life of spot welded lap shear joint of each steel are compared with predicted fatigue lives using different stress intensity factor solutions for kinked crack and spot weld available in literature. Micrographs of fatigue fractured surfaces are examined to understand fracture micro-mechanisms. [source] A robot-assisted study of intrinsic muscle regulation on proximal interphalangeal joint stiffness by varying metacarpophalangeal joint positionJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2006Zong-Ming Li Abstract The tightness of intrinsic hand muscles is a common cause of finger joint stiffness. The purposes of this study were to develop a robot-assisted methodology to obtain torque,angle data of a finger joint, and to investigate the regulation of the intrinsic muscles on finger joint stiffness. Our robot system features the integration of a low payload robot arm, a controller, and a force/torque transducer. The system provided highly reproducible torque,angle curves. Torque,angle data of the proximal interphalangeal joint with the metacarpophalangeal joint at 0 and 60 degrees were obtained from eight asymptomatic hands. The torque,angle curve shifted with the position of the metacarpophalangeal joint. As the metacarpophalangeal joint flexion angle changed from 60 to 0 degrees, the equilibrium of the proximal interphalangeal joint increased more than 20 degrees, and joint stiffness increased more than 50%. The dependence of the stiffness of the proximal interphalangeal joint on metacarpophalangeal joint position supports the regulatory role of the intrinsic muscles on finger joint mechanics. This regulatory mechanics is likely amplified in hands with intrinsic muscle tightness, justifying the commonly used Bunnell Intrinsic Tightness Test. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:407,415, 2006 [source] Stiffness, viscosity, and upper-limb inertia about the glenohumeral abduction axisJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2000Li-Qun Zhang To evaluate the dynamic properties of the shoulder and understand how they are controlled by the central nervous system, glenohumeral-joint stiffness and viscosity and upper-limb inertia were quantified under various levels of muscle contraction in seven healthy human subjects. Through a cast attachment, the upper limb was perturbed in a precise pattern by a computer-controlled servomotor to manifest the dynamic properties of the joint. The recorded joint position and torque were used to estimate joint stiffness and viscosity and upper-limb inertia. With moderate muscle contraction, the stiffness and viscosity increased several fold. A stiffer shoulder joint associated with stronger muscle contraction made the shoulder more stable and protected it from potential injuries during strenuous tasks. Joint viscosity, especially the stronger viscous damping associated with more strenuous contraction, smoothed shoulder movement and stabilized the joint. From the control viewpoint, the glenohumeral joint responded to the central nervous system more quickly with increasing muscle contraction, which was useful during strenuous tasks. On the other hand, the central nervous system controlled stiffness and viscosity synchronously so that it dealt with only a nearly constant damping ratio of the joint over various levels of contraction, which simplified its task substantially. This approach quantified the dynamic and static properties of the shoulder under various levels of contraction more accurately and completely than a manual test, and it can potentially be used to evaluate changes in these properties caused by musculoskeletal injuries and their surgical treatments. [source] Safety of Elective Hand Surgery Following Axillary Lymph Node Dissection for Breast CancerTHE BREAST JOURNAL, Issue 3 2007Dan D. Hershko MD Abstract:, The development of lymphedema is the most feared complication shared by breast cancer survivors undergoing hand surgery after prior axillary lymph node dissection (ALND). Traditionally, these patients are advised to avoid any interventional procedures in the ipsilateral upper extremity. However, the appropriateness of some of these precautions was recently challenged by some surgeons claiming that elective hand operations can be safely performed in these patients. The purpose of this study was to evaluate our experience and determine the safety of elective hand operations in breast cancer survivors. The medical records of patients operated for different hand conditions after prior breast surgery and ALND at our institution between 1983 and 2002 were reviewed. The techniques and preventive measures performed, use of antibiotics, and upper extremity complications associated with the operations were analyzed. Overall, we operated on 27 patients after prior ALND performed for breast cancer. Follow-up was available for 25 patients. Four patients had pre-existing lymphedema. The surgical technique used was similar to that performed in patients without prior ALND and antibiotic prophylaxis was not given. Delayed wound healing was observed in one patient and finger joint stiffness in another. Two patients with pre-existing lymphedema developed temporary worsening of their condition. None of the patients developed new lymphedema. The results of the present study support the few previous studies, suggesting that hand surgery can be safely performed in patients with prior ALND. Based on these findings, the appropriateness of the rigorous precautions and prohibitions regarding the care and use of the ipsilateral upper extremity may need to be reconsidered. [source] Influence of compartmental involvement on the patterns of morbidity in soft tissue sarcoma of the thighCANCER, Issue 1 2009Andreas Rimner MD Abstract BACKGROUD: The authors sought to determine whether differences existed in patterns of outcome and morbidity between the 3 thigh compartments after limb-sparing surgery and postoperative radiation therapy (RT). METHODS: A total of 255 patients with primary soft tissue sarcoma (STS) of the thigh were identified in our sarcoma database (1982,2002). More than 80% of tumors were >5 cm, high grade, and deep; 33% had close or positive microscopic resection margins. Adjuvant RT consisted of brachytherapy alone (BRT; 63%), external beam RT alone (EBRT; 31%), or a combination of brachytherapy and EBRT (6%). There were 125 anterior, 58 medial, and 72 posterior lesions. The 3 compartments were balanced as to tumor grade, size, depth, margin status, and RT type. RESULTS: Overall local control (LC) was 89%, distant metastases-free survival (DMFS) was 61%, and overall survival (OS) was 66% at 5 years (median follow-up, 71 months). Overall rates for complications at 5 years were wound reoperation (10%), edema (13%), joint stiffness (12%), nerve damage (8%), and bone fractures (7%). Wound reoperation and edema were significantly higher for medial-compartment tumors (P = .01 and .005, respectively), whereas nerve damage occurred more frequently in posterior-compartment tumors (P < .001). There were no differences among bone fracture, joint stiffness, DMFS, or OS rates between compartments. CONCLUSIONS: Although tumor control was similar for all 3 compartments, more wound reoperation and edema were observed in the medial compartment, and more nerve damage was noted in the posterior compartment. These results may help guide decisions concerning current patients and improve the design of future treatments tailored to compartments. Cancer 2009. © 2008 American Cancer Society. [source] | ||||||||||