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Arthroplasty Surgery (arthroplasty + surgery)

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Medical Sciences	100%

Selected Abstracts

Improved preoperative iron status assessment by soluble transferrin receptor in elderly patients undergoing knee and hip replacement

INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 6 2006
M. BASORA
Summary A poor preoperative haemoglobin (Hb) status is frequently encountered among adult patients scheduled for corrective surgery of the locomotive system, representing the main risk factor for blood transfusion. The soluble transferrin receptor (sTfR) has become a highly specific parameter for the detection of iron deficits as it can differentiate between iron deficiency anaemia and anaemia of chronic disease, because of the lack of effect by associated inflammation, unlike ferritin. The objectives of this study were to evaluate patients with the prevalence of risk for transfusion, the effect of inflammation on ferritin (F) values and functional iron deficiency in elderly patients with advanced degenerative arthropathy scheduled for hip or knee replacement. This observational, prospective study included patients over 50 years, operated for hip or knee replacements between April and June 2004. Of 218 patients studied, 87 (39%) presented with Hb levels between 10 and 13 g/dl. The prevalence of functional iron deficit was 27% (sTfR > 1.76 mg/l), while only 8.6% of patients displayed F levels below normal. As expected, C-reactive protein levels were elevated in 24.8% of patients and erythrocyte sedimentation rate was elevated in 50%. These inflammatory markers did not correlate with levels of either F or sTfR. Multiple factors can affect F levels, such as the inflammatory status of osteoarthritis in the elderly, obesity, nonsteroidal anti-inflammatory drugs therapy and low physical performance. As sTfR is not affected by inflammation, it has emerged as a primary parameter for the evaluation of iron status during preoperative assessment among patients scheduled for arthroplasty surgery. Our data strongly suggest that sTfR measurement contributes to improve patient management. [source]

Towards automatic computer-aided knee surgery by innovative methods for processing the femur surface model

THE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 3 2010
Pietro Cerveri
Abstract Background The femoral shaft (FDA) and transepicondylar (TA), anterior,posterior (WL) and posterior condylar (PCL) axes are fundamental quantities in planning knee arthroplasty surgery. As an alternative to the TA, we introduce the anatomical flexion axis (AFA). Obtaining such axes from image data without any manual supervision remains a practical objective. We propose a novel method that automatically computes the axes of the distal femur by processing the femur mesh surface. Methods Surface data were processed by exploiting specific geometric, anatomical and functional properties. Robust ellipse fitting of the two-dimensional (2D) condylar profiles was utilized to determine the AFA alternative to the TA. The repeatability of the method was tested upon 20 femur surfaces reconstructed from CT scans taken on cadavers. Results At the highest surface resolutions, the relative median error in the direction of the FDA, AFA, PCL, WL and TA was < 0.50°, 1.20°, 1.0°, 1.30° and 1.50°, respectively. As expected, at the lowest surface resolution, the repeatability decreased to 1.20°, 2.70°, 3.30°, 3.0° and 4.70°, respectively. The computed directions of the FDA, PCL, WL and TA were in agreement (0.60°, 1.55°, 1.90°, 2.40°) with the corresponding reference parameters manually identified in the original CT images by medical experts and with the literature. Conclusions The proposed method proved that: (a) the AFA can be robustly computed by a geometrical analysis of the posterior profiles of the two condyles and can be considered a useful alternative to the TA; (b) higher surface resolutions leads to higher repeatability of all computed quantities; (c) the TA is less repeatable than the other axes. Copyright © 2010 John Wiley & Sons, Ltd. [source]

HyBAR: hybrid bone-attached robot for joint arthroplasty

THE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 2 2009
S. Song
Abstract Background A number of small bone-attached surgical robots have been introduced to overcome some disadvantages of large stand-alone surgical robots. In orthopaedics, increasing demand on minimally invasive joint replacement surgery has also been encouraging small surgical robot developments. Among various technical aspects of such an approach, optimal miniaturization that maintains structural strength for high speed bone removal was investigated. Methods By observing advantages and disadvantages from serial and parallel robot structures, a new hybrid kinematic configuration was designed for a bone-attached robot to perform precision bone removal for cutting the femoral implant cavity during patellofemoral joint arthroplasty surgery. A series of experimental tests were conducted in order to evaluate the performance of the new robot, especially with respect to accuracy of bone preparation. Results A miniaturized and rigidly-structured robot prototype was developed for minimally invasive bone-attached robotic surgery. A new minimally invasive modular clamping system was also introduced to enhance the robotic procedure. Foam and pig bone experimental results demonstrated a successful implementation of the new robot that eliminated a number of major design problems of a previous prototype. Conclusions For small bone-attached surgical robots that utilize high speed orthopaedic tools, structural rigidity and clamping mechanism are major design issues. The new kinematic configuration using hinged prismatic joints enabled an effective miniaturization with good structural rigidity. Although minor problems still exist at the prototype stage, the new development would be a significant step towards the practical use of such a robot. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Controversies of thrombophylaxis following knee arthroplasty surgery

ANZ JOURNAL OF SURGERY, Issue 6 2010
David Campbell BM, FRACS
First page of article [source]

Fate of the infrapatellar branch of the saphenous nerve post total knee arthroplasty

ANZ JOURNAL OF SURGERY, Issue 9 2005
Dinshaw Mistry
Background:, The infrapatellar branch of the saphenous nerve is a known cause of morbidity following knee surgery. The incidence of sensory changes following total knee arthroplasty, and its effect on patient satisfaction with arthroplasty surgery remain undocumented. Our aim was to document the incidence of infrapatellar nerve palsy following total knee arthroplasty and its effect on patient satisfaction. Methods:, Between 1 January 2002 and 31 December 2003 all patients attending outpatients clinic for primary total knee joint arthroplasty were prospectively tested for sensory defects. Patients were then assessed postoperatively and satisfaction was measured using the British Orthopaedic Satisfaction Score and a visual analogue scale. Results:, Thirty-one patients satisfied inclusion criteria of which 21 agreed to participate. One patient was excluded later in the study leaving 20 patients. Seventy per cent of patients had sensory changes in the area supplied by the infrapatellar branch of the saphenous nerve. Patient satisfaction scores did not correlate to the presence of a sensory deficit. Two patients stated that the sensory deficit was a significant factor in their dissatisfaction with their arthroplasty surgery. Conclusions:, Sensory changes due to damage to the infrapatellar branch of the saphenous nerve during total knee joint arthroplasty is a common occurrence and can interfere with patient satisfaction. Patients should be informed of this risk in the preoperative discussion. [source]