Design and Biomechanics of the Oxford Knee

2015 ◽  
Author(s):  
John Goodfellow ◽  
John O'Connor ◽  
Hemant Pandit ◽  
Christopher Dodd ◽  
David Murray
Keyword(s):  
Minimal Risk ◽  
Knee Prostheses ◽  
Obvious Advantage ◽  
Joint Surfaces ◽  
Cementless Components

The description of the Oxford Knee starts with an explanation of the function of mobile bearings in knee prostheses. An obvious advantage is that the areas of contact between the joint surfaces are maximised. In this chapter, we shall show that wear at the polyethylene surfaces is thereby minimised and that optimal kinematics can be achieved with minimal risk of loosening. We will discuss the biomechanics of the cementless components and problems that may occur with the tibia.

For Those About to Rock

2012 ◽  
Vol 13 (1) ◽  
pp. 29-35
Author(s):  
Jennifer Tufts
Keyword(s):  
Hearing Loss ◽  
Cultural Landscape ◽  
Minimal Risk ◽  
Noise Induced Hearing Loss ◽  
Essential Information ◽  
Informed Decisions ◽  
Hearing Health ◽  
Loud Music ◽  
Protective Strategies

Loud music and noisy hobbies are part of our cultural landscape. These activities can be enjoyed with minimal risk to hearing if a few commonsense guidelines are followed. Educating clients about risks and protective strategies will empower them to make informed decisions about their hearing health that best reflect their values and priorities. In this article, the author covers essential information to avoiding noise-induced hearing loss, writing in easily accessible language to better help clinicians convey this information to their clients.

Hemophilic Bledding Evaluated by Blood Pool Scanning

1981 ◽  
Vol 45 (03) ◽  
pp. 208-210 ◽  
Author(s):  
D Green ◽  
S M Spies ◽  
N A Rana ◽  
J W Milgram ◽  
R Mintzer
Keyword(s):  
Blood Volume ◽  
Blood Pool ◽  
Invasive Technique ◽  
Scintillation Camera ◽  
Knee Prostheses ◽  
Hemophilic Patient ◽  
Chronic Arthropathy ◽  
Image Density ◽  
Regional Blood Volume

SummaryThe technique of blood pool scanning was used to examine 15 hemophilic subjects. Employing an in vivo method for erythrocyte labeling with Technetium-99 m, a dynamic perfusion sequence is obtained using a scintillation camera positioned over the area to be examined. This demonstrates the vascularity of the tissue. Subsequently, equilibrium blood pool images of the area are obtained and analyzed with a densitometer to assess relative regional blood volume. In patients who were not bleeding but had chronic arthropathy, vascularity was not increased, and the blood volume of comparable joints was similar. By contrast, marked increases in vascularity and image density were observed in studies of acutely bleeding joints. Chronic hemarthroses were associated with persistent, but less marked increases in joint perfusion. Transient increases in joint vascularity were demonstrated after insertion of knee prostheses. In a patient with a thigh hematoma, the dimensions of the hemorrhage were clearly delineated. Since only a tracer dose of nuclide is infused intravenously, there are no allergic reactions or other side effects of the procedure. Blood pool scanning is a safe, non-invasive technique that augments clinical and radiographic evaluations, and provides a new dimension in the assessment of the hemophilic patient.

X-ray Follow-up after Open Reduction Internal Fixation of Distal Forearm Fracture

2020 ◽  
Author(s):  
Henrik Johan Sjølander ◽  
Sune Jauffred ◽  
Michael Brix ◽  
Per H. Gundtoft
Keyword(s):  
Diagnostic Imaging ◽  
Forearm Fracture ◽  
Minimal Risk ◽  
Distal Forearm ◽  
Forearm Fractures ◽  
Distal Forearm Fracture ◽  
Standard Regimen ◽  
Prolonged Immobilization ◽  
Distal Forearm Fractures

Abstract Background Following surgery, the standard regimen for fractures of the distal forearm includes radiographs taken 2-weeks postoperatively. However, it is unclear whether these radiographs have any therapeutic risks or benefits for patients. Objective The purpose of this study is to determine the importance of radiographs taken 2-weeks after surgery on distal forearm fractures, especially if it leads to further operations, and to establish whether this practice should be continued. Materials and Methods This is a retrospective cohort study of patients with a distal forearm fracture treated surgically with a volar locking plate at two university hospitals in Denmark. Standard aftercare at both departments is 2 weeks in a cast. Patients attend a 2-week follow-up, at which the cast is replaced with a removable orthosis and radiographs are taken. It was recorded whether these radiographs had resulted in any change of treatment in terms of further operations, prolonged immobilization, additional clinical follow-up, or additional diagnostic imaging. Results A total of 613 patients were included in the study. The radiographs led to a change of standard treatment for 3.1% of the patients. A second operation was required by 1.0%; 0.5% were treated with prolonged immobilization, and 1.6% had additional outpatient follow-up due to the findings on the radiographs. Additional diagnostic imaging was performed on 1.9% of the patients. Conclusion The radiographs taken at the 2-weeks follow-up resulted in a change of treatment in 3.1% of the cases. Given the low cost and minimal risk of radiographs of an extremity, we concluded that the benefits outweigh the costs of routine radiographs taken 2 weeks after surgical treatment of distal forearm fractures.

In-block lateralization as a new technique for mobilization of the inferior alveolar nerve: a technique case series

2020 ◽  
Author(s):  
Marcos Augusto Tomazi ◽  
Alexandre da Silveira Gerzson ◽  
Angelo Menuci Neto ◽  
André Luciano Pasinato da Costa
Keyword(s):  
Treatment Options ◽  
Inferior Alveolar Nerve ◽  
Case Series ◽  
New Technique ◽  
Autogenous Bone ◽  
Minimal Risk ◽  
Short Implants ◽  
Bone Atrophy ◽  
A New Technique ◽  
Number Of Treatment

The edentulous atrophic posterior mandible is often a great challenge for implant rehabilitation. Although a number of treatment options have been proposed, including the use of short implants and surgical grafting techniques, in cases of severe bone atrophy, techniques for mobilization of the inferior alveolar nerve (IAN) have been shown to be efficient, with good results. Four female patients underwent IAN lateralization for prosthetic rehabilitation of the posterior mandible from 2013 to 2019, with 1 year to 5 years and 4 months of follow-up. This case series describes a new technique for mobilization of the IAN, named in-block lateralization, to facilitate access to the IAN and to reduce nerve manipulation. The implant is immediately installed (allowing nerve lateralization in unitary spaces) and the original mandibular anatomy is restored with autogenous bone from the original bed during the same surgical procedure. When well indicated and well performed, this new approach provides better and easier visualization of the IAN as well as safer manipulation aiming to achieve good results for implant stability and minimal risk of neurosensory disturbances, allowing rehabilitation even in unitary spaces.

Evaluation of aseptic loosening of knee prostheses by quantitative bone scintigraphy

2008 ◽  
Vol 47 (04) ◽  
pp. 163-166 ◽  
Author(s):  
D. Steiner ◽  
S. Laurich ◽  
R. Bauer ◽  
J. Kordelle ◽  
R. Klett
Keyword(s):  
Aseptic Loosening ◽  
Bone Scintigraphy ◽  
Revision Surgery ◽  
Predictive Value ◽  
Knee Prostheses ◽  
Treatment Regimes ◽  
Golden Standard ◽  
The Difference ◽  
Sensitivity Specificity ◽  
Asymptomatic Control

SummaryIn not infected knee prostheses bone scintigraphy is a possible method to diagnose mechanical loosening, and therefore, to affect treatment regimes in symptomatic patients. However, hitherto studies showed controversial results for the reliability of bone scintigraphy in diagnosing loosened knee prostheses by using asymptomatic control groups. Therefore, the aim of our study was to optimize the interpretation procedure and to evaluate the accuracy using results from revision surgery as standard. Methods: Retrospectively, we were able to examine the tibial component in 31 cemented prostheses. In this prostheses infection was excluded by histological or bacteriological examination during revision surgery. To quantify bone scintigraphy, we used medial and lateral tibial regions with a reference region from the contralateral femur. Results: To differentiate between loosened and intact prostheses we found a threshold of 5.0 for the maximum tibia to femur ratio of the both tibial regions and a threshold of 18% for the difference of the ratio of both tibial regions. Using these thresholds, values of 0.9, 1, 0.85, 1, and 0.94 were calculated for sensitivity, specificity, negative predictive value, positive predictive value, and accuracy, respectively. To get a sensitivity of 1, we found a lower threshold of 3.3 for the maximum tibia to femur ratio. Conclusion: Quantitative bone scintigraphy appears to be a reliable diagnostic tool for aseptic loosening of knee prostheses with thresholds evaluated by revision surgery results being the golden standard.

3D Printing as a Way of Integrating Mathematical Models in Arthroscopic Knee Surgery

2018 ◽  
Vol 69 (9) ◽  
pp. 2501-2507
Author(s):  
Anca Plavitu ◽  
Mark Edward Pogarasteanu ◽  
Marius Moga ◽  
Mircea Lupusoru ◽  
Florentina Ionita Radu ◽  
...  
Keyword(s):  
Knee Joint ◽  
Osteochondral Defect ◽  
Surgical Intervention ◽  
Operating Time ◽  
Vascular Pathology ◽  
Osteochondral Lesions ◽  
Joint Surfaces ◽  
Novel Method ◽  
Technological Means ◽  
Arthroscopic Knee

Our objective is to develop a novel method of approaching the arthroscopic treatment of osteochondral lesions within the knee joint by using mathematics as a way of understanding the geometry involved in the knee, both in normal and degenerated knee joint surfaces. Bone and cartilage lesions are frequent, whether as a result of trauma, degenerative pathology, vascular pathology (osteocondritis dissecans) or tumoral. In all cases, a defect can be repaired arthroscopically, if it has manageable dimensions and if the surgeon has the technological means and the necessary skills, through the use of grafts (autografts or allografts). Alternatively, a lesion that may be approached arthroscopically initially could prove to be too great for repair and may need a second intervention for reconstruction with an endoprosthesis. We aim to further deepen the surgeon�s understanding of this pathology, through the use of 3D technology as a way of representing the osteochondral defect. Thus, its dimensions and position may be better understood, and the surgical intervention may be better planned out, potentially resulting in a shorter operating time and an overall superior outcome for the patient, and even potentially diminishing the number of unnecessary surgeries performed.

Evaluation of Cartilage in the Wrist using Magnetic Resonance Imaging

2020 ◽  
Vol 16 (3) ◽  
pp. 170-177
Author(s):  
Wesley N. Sivak ◽  
Joseph E. Imbriglia
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Wrist Arthroscopy ◽  
Resonance Imaging ◽  
Joint Surfaces ◽  
Articular Cartilage Surface ◽  
Small Joint ◽  
Magnetic Resonance Imaging Mri ◽  
Clinical Conditions ◽  
Accurate Imaging

Wrist pain is a common patient complaint with a myriad of clinical conditions that can explain the underlying cause. Short of wrist arthroscopy, no technique other than formal wrist arthrotomy exists for direct examination of the hyaline cartilage coating the articular surfaces of the carpal bones. Magnetic resonance imaging (MRI) has been proven accurate in evaluating joint surfaces of large joints such as the shoulder, hip, and knee with articular cartilage surface thickness is in excess of 1 mm. However, in the carpus the thickness of the cartilage and the contours present have precluded accurate imaging. Advances in MRI technology over the last several decades are now making imaging of small joint surfaces, such as the carpus, an area worth revisiting. Herein we provide a review of these efforts with a specific focus on the evaluation of the wrist.

Efficacy and Cardiovascular Safety of Meglitinides

2020 ◽  
Vol 15 ◽  
Author(s):  
Jim Philip ◽  
Cornelius James Fernandez
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Cardiovascular Outcomes ◽  
Individual Therapy ◽  
Hypoglycemic Agents ◽  
Current Evidence ◽  
Minimal Risk ◽  
Cardiovascular Safety

: Meglitinides are a group of oral hypoglycemic medications currently approved for the treatment of type 2 diabetes mellitus (T2DM). Two meglitinide molecules, Repaglinide and Nateglinide,are presently in use. Repaglinide is preferred because of its superior glycemic efficacy.They have modest efficacy with a mean decrement of glycosylated haemoglobin (HbA1c) ranging between -0.2 to -1.50% with individual therapy. Additional HbA1c reduction can occur with combination therapy with other oral hypoglycemics. This class of drugs is effective in controlling postprandial hyperglycemia with minimal risk of hypoglycemia.It is also useful in patients in with variable meal timings, especially in the elderly, and in patients with renal failure. There are is a dearth of long-term studies on meglitinides to assess cardiovascular outcomes or mortality in T2DM,although the Nateglinide and Valsartan in Impaired Glucose ToleranceOutcomes Research (NAVIGATOR) study showed no difference between Nateglinide and placebo with regard to the core composite cardiovascular outcomes. Based on a PubMed literature search using key words: ‘meglitinides’, ‘repaglinide’, ‘nateglinide’, ‘HbA1c’, ‘glycated haemoglobin’, ‘cardiovascular safety’, ‘cardiovascular events’, ‘cardiovascular outcome trials’, ‘type 2 diabetes mellitus’ and heart failure, and combining the search terms using Boolean operators ‘AND’, ‘OR’ and ‘NOT’ as needed we compiled current evidence for use of these oral hypoglycemic agents in clinical use. This article is an attempt to review the efficacy and cardiovascular (CV) safety of Meglitinides to help clinicians to use this class of oral hypoglycaemic agents prudently.

scholarly journals Three-dimensional ultrasound for knee osteophyte depiction: a comparative study to computed tomography

2021 ◽  
Author(s):  
Valeria Vendries ◽  
Tamas Ungi ◽  
Jordan Harry ◽  
Manuela Kunz ◽  
Jana Podlipská ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Automatic Segmentation ◽  
Three Dimensional ◽  
3D Ultrasound ◽  
Surgical Interventions ◽  
Structured Light Scanner ◽  
Joint Surfaces ◽  
Operative Planning ◽  
Rms Error ◽  
Tissue Characteristics

Abstract Purpose Osteophytes are common radiographic markers of osteoarthritis. However, they are not accurately depicted using conventional imaging, thus hampering surgical interventions that rely on pre-operative images. Studies have shown that ultrasound (US) is promising at detecting osteophytes and monitoring the progression of osteoarthritis. Furthermore, three-dimensional (3D) ultrasound reconstructions may offer a means to quantify osteophytes. The purpose of this study was to compare the accuracy of osteophyte depiction in the knee joint between 3D US and conventional computed tomography (CT). Methods Eleven human cadaveric knees were pre-screened for the presence of osteophytes. Three osteoarthritic knees were selected, and then, 3D US and CT images were obtained, segmented, and digitally reconstructed in 3D. After dissection, high-resolution structured light scanner (SLS) images of the joint surfaces were obtained. Surface matching and root mean square (RMS) error analyses of surface distances were performed to assess the accuracy of each modality in capturing osteophytes. The RMS errors were compared between 3D US, CT and SLS models. Results Average RMS error comparisons for 3D US versus SLS and CT versus SLS models were 0.87 mm ± 0.33 mm (average ± standard deviation) and 0.95 mm ± 0.32 mm, respectively. No statistical difference was found between 3D US and CT. Comparative observations of imaging modalities suggested that 3D US better depicted osteophytes with cartilage and fibrocartilage tissue characteristics compared to CT. Conclusion Using 3D US can improve the depiction of osteophytes with a cartilaginous portion compared to CT. It can also provide useful information about the presence and extent of osteophytes. Whilst algorithm improvements for automatic segmentation and registration of US are needed to provide a more robust investigation of osteophyte depiction accuracy, this investigation puts forward the potential application for 3D US in routine diagnostic evaluations and pre-operative planning of osteoarthritis.

scholarly journals Delayed lumbar plexus palsy due to giant psoas hematoma associated with vertebral compression fracture and direct oral anticoagulants: a case report

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Chikako Ishii ◽  
Miki Komatsu ◽  
Kota Suda ◽  
Masahiko Takahata ◽  
Satoko Matsumoto Harmon ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Atrial Fibrillation ◽  
Cerebral Infarction ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Lumbar Plexus ◽  
Vertebral Compression Fractures ◽  
Minimal Risk ◽  
Motor Weakness ◽  
Segmental Artery

Abstract Background Osteoporotic vertebral compression fractures (VCFs) are commonly observed in elderly people and can be treated by conservatively with minimal risk of complications in most cases. However, utilization of direct oral anticoagulants (DOACs) increases the risks of secondary hematoma even after insignificant trauma. The use of DOACs increased over the past decade because of their approval and recommendation for both stroke prevention in non-valvular atrial fibrillation and treatment of venous thromboembolism. It is well known that DOACs are safer anticoagulants than warfarin in terms of major and nonmajor bleeding; however, we noted an increase in the number of bleeding events associated with DOACs that required medical intervention. This report describes the first case of delayed lumbar plexus palsy due to DOAC-associated psoas hematoma after VCF to draw attention to potential risk of severe complication associated with this type of common and stable trauma. Case presentation An 83-year-old man presented with his left inguinal pain and inability to ambulate after falling from standing position and was prescribed DOACs for chronic atrial fibrillation. Computed tomography angiography revealed a giant psoas hematoma arising from the ruptured segmental artery running around fractured L4 vertebra. Because of motor weakness of his lower limbs and expansion of psoas hematoma revealed by contrast computed tomography on day 8 of his hospital stay, angiography aimed for transcatheter arterial embolization was tried, but could not demonstrate any major active extravasation; therefore spontaneous hemostasis was expected with heparin replacement. On day 23 of his stay, hematoma turned to decrease, but dysarthria and motor weakness due to left side cerebral infarction occurred. His pain improved and bone healing was achieved about 2 months later from his admission, however the paralysis of the left lower limb and aftereffects of cerebral infarction remained after 1 year. Conclusion In patients using DOACs with multiple risk factors, close attention must be taken in vertebral injury even if the fracture itself is a stable-type such as VCF, because segmental artery injury may cause massive psoas hematoma followed by lumbar plexus palsy and other complications.

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