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Biomedical subjects

J M Cuckler

Publications and source records attributed to J M Cuckler.

At least 37 records · Page 2Linked to original sources
PubMed1995

Cost effectiveness of intraoperative autotransfusion in total hip arthroplasty surgery.

The purpose of this study was to analyze the cost effectiveness of the cell saver in reducing homologous blood transfusion requirements in patients undergoing primary total hip arthroplasties. In patients who had predonated autologous blood, the addition of the cell saver neither reduced the homologous blood requirements nor the percentage of patients exposed to banked blood. In patients without predonated autologous blood, the cell saver decreased the percentage of patients exposed to banked blood by 40% and decreased the mean homologous transfusion requirement from 2.6 to 1.5 units per patient (p < 0.05). The cell saver became cost effective when 3 units of blood were salvaged. Because the cell saver reclaimed a mean of 453 ml (approximately 2 units), it was not cost effective. This analysis is confounded by the risk of exposure to blood borne potentially life-threatening pathogens. In patients undergoing elective primary hip arthroplasty, the availability of predonated autologous blood obviates the need for expensive intraoperative blood salvage techniques. If an adequate volume of autologous blood cannot be procured preoperatively, or if the clinician suspects excessive intraoperative bleeding, then using the cell saver may be justified.

Blood Loss, Surgical↗
PubMed1995

Femoral head technologies to reduce polyethylene wear in total hip arthroplasty.

Efforts to reduce production of polyethylene wear debris are critical to improve the long-term success of total hip arthroplasty. A variety of factors affect the wear between the femoral head and polyethylene acetabular component. Methods of measuring smoothness of femoral heads, the performance of metal alloys and ceramic materials, and the clinical experience comparing the performance of cobalt chrome and ceramic materials are discussed. The rationale for the clinical use of ceramic materials in young, active patients is justified by the current laboratory data from wear testing experiments, but awaits clinical validation.

Femur Head↗
PubMed1994

Comparison of the inflammatory response to particulate polymethylmethacrylate debris with and without barium sulfate.

Particulate polymethylmethacrylate debris has been implicated in the inflammatory response observed surrounding loosened cemented implants. The rat subcutaneous pouch model and the Howie implant model (used to study bone resorption) were used to quantify the response to mechanically produced endotoxin-free polymethylmethacrylate debris with and without 10% (wt/vol) BaSO4. In the rat subcutaneous pouch model, the inflammatory response to polymethylmethacrylate particles containing BaSO4 was greater than the response to plain polymethylmethacrylate particles of similar size. Increased inflammation was measured by leukocyte counts and levels of prostaglandin E2, tumor necrosis factor, and neutral metalloprotease. In addition, particulate polymethylmethacrylate with BaSO4 caused significantly greater bone resorption in the Howie model than did particulate plain polymethylmethacrylate. In in vitro studies, particulate polymethylmethacrylate with BaSO4 stimulated more prostaglandin E2, neutral metalloprotease, and tumor necrosis factor from human monocytes in culture and stimulated greater proliferation of synovial cells than did particulate plain polymethylmethacrylate. The presence of BaSO4 appears to significantly intensify the inflammatory response to polymethylmethacrylate debris.

Animals↗
PubMed1994

An algorithm for the management of femoral neck fractures.

The choice of total hip arthroplasty should probably be reserved for those rare patients with preexisting osteoarthritis of the hip in the setting of a subcapital hip fracture. Additionally, relative indications for total hip arthroplasty may include the presence of contralateral hip disease; the presence of metabolic bone disease, which may controvert internal fixation or reasonable results with endoprosthetic replacement; and those patients with high activity expectations or life expectancy greater than 5 years. Given the diminished performance of hemiarthroplasty with time and activity, it may be argued that the most cost effective solution to the subcapital hip fracture in the majority of patients may be the reduction and internal fixation pathway, with elective conversion, when necessary, of the approximately 25% of patients who suffer avascular necrosis to total hip arthroplasty. It appears that hemiarthroplasty is best suited for the elderly household ambulator, whereas total hip arthroplasty is the better alternative either as the elective solution to failed internal fixation of femoral neck fractures or in the occasional community ambulator with high activity expectations and irreducible femoral neck fractures. Younger patients, and those with minimally displaced fractures, should be treated with internal fixation in an attempt to preserve the natural hip joint.

Algorithms↗
PubMed1994

Fractographic analysis of failed porous and surface-coated cobalt-chromium alloy total joint replacements.

Fractographic analyses were performed on retrieved porous and surface-coated cobalt-chromium alloy prostheses which were revised because of metallurgical fracture. Two femoral neck fractures and one fractured post of a femoral component of a total knee replacements were retrieved and analyzed via light, stereo and scanning electron microscopy (SEM). In all cases, fatigue was the mechanism of failure. The life time of these prostheses was 3-5 years. The porous coating; microstructural features, including large grains, carbides, porosity, inclusions and defects; design and manufacturing defects were all likely causative factors in these fatigue failures. In light of these and other reported fractures, further study of fatigue mechanisms and improvement of design and manufacturing processes are warranted.

Adult↗
PubMed1993

Microstructural pathway of fracture in poly(methyl methacrylate) bone cement.

Mechanical failure of poly(methyl methacrylate) (PMMA) bone cement is linked to failure of cemented total joint prostheses. An essential step to minimize, if not eliminate, cement fracture is to understand the material characteristics controlling fracture resistance. At least four phases of bone cement can be identified that may affect the damage zone formation: pre-polymerized beads, interbead matrix polymer, BaSO4, and porosity. Gel permeation chromatography (GPC) was used to determine the molecular weight (MW) distributions of the two polymer phases. Mechanical testing, scanning electron microscopy and light microscopy were used to analyse fracture mechanisms. Fatigue crack propagation of bone cement was distinctly different from rapid crack propagation. Microcracks defined the damage zone for fatigue fracture. The microcracks developed in the interbead matrix and not through the pre-polymerized beads. Light microscopy revealed evidence of craze formation on surfaces of fractured beads during rapid fracture, but not on fatigue surfaces. GPC analysis indicated an increase in MW from the bead phase alone to the fully cured bone cement, indicating a greater MW in the interbead matrix polymer. Increases of 36 and 176% were measured for two different bone cements, but the bulk of the polymer has an MW of less than 1 x 10(6). Three factors were suggested to explain why the microcracks seem to prefer to grow in the interbead matrix: the presence of BaSO4, shrinkage during the curing process, and the different polymerization processes of the bead and the interbead polymers.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMed1993

Diffuse chondrolytic arthritis in sickle cell disease.

A young black man with sickle cell disease with recurrent painful vasoocclusive crises developed at 16 years of age a rapid disabling polyarticular chondrolysis leading to a bilateral hip arthroplasty in 1 year. Light microscopy showed erosion and chondrocyte loss with deep clones in the cartilage and congested vessels with extravasation of red blood cells and mononuclear cells in the synovium. Electron microscopy of the synovium disclosed partially occluded blood vessels and phagocytic cells containing red blood cell debris and crystalline hemoglobin-like material. These observations suggest a role for the phagocytic cells in the joint destruction.

Adult↗
PubMed1992

The fracture toughness of titanium-fiber-reinforced bone cement.

Fracture of the poly(methyl methacrylate) bone cement mantle can lead to the loosening and ultimate failure of cemented total joint prostheses. The addition of fibers to the bone cement increases fracture resistance and may reduce, if not eliminate, in vivo fracturing. This study discusses the effect of incorporating titanium (Ti) fibers on fracture toughness. Essential characteristics of the composite bone cement included a homogeneous and uniform fiber distribution, and a minimal increase in apparent viscosity of the polymerizing cement. Ti fiber contents of 1%, 2%, and 5% by volume increased the fracture toughness over non-reinforced bone cement by up to 56%. Bone cements of two different viscosities were used as matrix material, but when reinforced with the same fiber type and content, they showed no difference in fracture toughness. Four different fiber aspect ratios (68, 125, 227, 417) were tested. At 5% fiber content, there was no statistically significant dependence of fracture toughness on fiber aspect ratio. Scanning electron microscopy revealed important toughening mechanisms such as fiber/matrix debonding, local fracture path alteration, and ductile fiber deformation and fracture. Fiber fracture was evidence that the critical fiber length was exceeded. The surfaces of the Ti fibers were rough and irregular, indicating that a high degree of mechanical interlock between matrix and fiber was likely. The energy absorption contribution of plastic deformation and ductile fracture is absent in brittle fibers, like carbon, but is a distinction of the Ti fibers used in this study.

Biocompatible Materials↗
PubMed1992

Field distributions in the rat tibia with and without a porous implant during electrical stimulation: a parametric modeling.

Expeditious post-operative ingrowth of bone is necessary for clinically successful fixation of porous joint prostheses. Electrical or electromagnetic fields to stimulate bone growth into porous implants have been used; however, they produced nonconvincing data. This was partially attributable to the lack of quantification of the localized electric fields produced in the pores of the implants. Therefore, this study set out: i) to quantify the local electric field values induced into the surface pores of nonconducting implants by "capacitive" coupling and to determine the magnitude of the macroscopically applied capacitively coupled electrical currents to induce specific electric field amplitudes in the pores, ii) to identify the important dielectric properties of the implant-tissue interface, and iii) to create the basis for successfully applying electrical fields in an animal model to stimulate bone ingrowth. A finite element method was used to calculate the electric field gradients and current densities present in a rat tibia modeled with a porous intramedullary implant when capacitively stimulated. Results indicated that while the current density in the pores are reduced in comparison to the region just outside the pore by about one order of magnitude, a significant current density still exists in the pore region. Furthermore, the presence of the implant increases the current densities in the trabecular bone while decreasing these values in the cortical bone. Replacing the trabecular bone in the pore by saline increases the current density in the pore by three-fold, but decreases the voltage gradient by a similar factor.

Animals↗
PubMed1992

Bioactive ceramic prosthetic coatings.

The concept of bioactive ceramic coatings on macroscopically smooth prostheses tries to reconcile opposing principles: the ceramic with beneficial bone tissue growth effects is used as a coating since it does not have sufficient strength and toughness to be used by itself as a prosthesis material. But strength is still an issue since the coating is the primary means of transferring stresses from prosthesis to surrounding tissues. The interface between the metal core and ceramic surface is then critical, since it essentially depends on the strength characteristics of the ceramic. Conversely, when the ceramic coating is used as a means to enhance bone-tissue formation around and into the prosthesis surface, thereby helping to establish a mechanical form of retention, the adhesion of ceramic coating to metallic substrate is not critical. The optimum characteristics of the ceramic are then those that produce the highest effect on bone-tissue growth rates immediately after surgery. The rate of bioactivity is related to the chemical reactivity of the material causing interfacial dissolution, precipitation, and ion exchange reactions. Furthermore, it also appears to depend on a substratum function affecting mineral precipitation, collagen deposition, and cellular differentiation and proliferation.

Biocompatible Materials↗
PubMed1992

Evaluation of the painful total hip arthroplasty.

Total hip arthroplasty is a common technique for the surgical management of degenerative hip disease. Because of the increasing number of patients and the variety of prostheses and fixation modalities available to the surgeon, the evaluation of the patient with a painful arthroplasty has become an increasingly complex endeavor. The growing number of patients who undergo multiple revision surgeries further complicates the evaluation of the painful arthroplasty. Other complicating factors include the lack of absolute sensitivity and specificity of the variety of diagnostic techniques and the difficulty of differentiating pain caused by septic verses aseptic loosening. This report reviews the recent literature concerning the evaluation of the painful total hip arthroplasty and provides a clinical rationale for the assessment of the painful total hip arthroplasty.

Diagnosis, Differential↗
PubMed1991

Alternatives to hip, knee, and ankle total joint arthroplasty.

Although total joint arthroplasty is the most commonly performed procedure for the treatment of advanced stages of degenerative joint diseases, alternatives to joint replacement remain essential to the armamentarium of the clinician. For the hip, knee, and ankle, alternatives such as synovectomy, osteotomy, and fusion should be considered when contraindications to joint replacement exist. The indications and results of these procedures are discussed as reflected by a review of the recent literature.

Ankle Joint↗
PubMed1991

Diagnosis and management of the infected total joint arthroplasty.

The preoperative diagnosis of the infected orthopedic implant is complicated by lack of a single precise test to forewarn patient and surgeon of the presence of microorganisms. Given the overall limitation of accuracy of preoperative diagnosis to approximately 80% when 111In scanning, preoperative aspiration, and ESR are considered, it would seem prudent to approach each revision surgery with the possibility in mind of subclinical sepsis as the cause for failure of the implant. The essentials of surgical technique including thorough debridement of the wound and removal of all existing foreign bodies, especially including PMMA bone cement, are critical to minimizing the risk for occurrence or persistence of sepsis. Although the use of antibiotic impregnated bone cement may enhance the treatment of orthopedic sepsis, the data available to date lead to the conclusion that two-stage revision surgery in the face of known sepsis remains the cornerstone of surgical therapy for the infected implant, along with aggressive and rational antibiotic treatment. The surgeon is offered the following guidelines in the management of the septic total hip arthroplasty. 1. Preoperative evaluation including ESR, 111In WBC scan, and aspiration for culture and sensitivity (fluoroscopically guided for the hip) will produce on average approximately 80% accuracy. 2. Intraoperative cultures at the time of revision surgery should be obtained prior to administration of systemic antibiotics; three tissue specimens (hip capsule, femoral membrane, acetabular membrane) should be submitted for culture and sensitivity determination. 3. Careful debridement of the surgical site of granulation tissue and all foreign bodies (e.g., PMMA) should be performed within the limits of patient safety to maximize the likelihood of success.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

A fractographic analysis of in vivo poly(methyl methacrylate) bone cement failure mechanisms.

Cementing with poly(methyl methacrylate) (PMMA) is a common means of fixing total hip prostheses. Bone cement fails mechanically, and subsequent loosening frequently requires correction via revision surgery. An initial step in optimizing bone cement properties is to establish which properties are critical to the material's in vivo performance. The objectives were to discern the critical in vivo failure mechanisms of bone cement. Fracture surfaces of bone cement specimens that failed in vivo were compared with fatigue and rapid fracture surfaces created in vitro. In vivo fracture processes of bone cement were positively identified and explained by the elucidation of PMMA fracture micromechanisms. The ex vivo fracture surfaces are remarkably similar to in vitro fatigue fracture surfaces. The fractographic data document that the primary in vivo failure mechanism of bone cement is fatigue, and the fatigue cracks grow by developing a microcraze shower damage zone. Agglomerates of BaSO4 particles can be implicated in some bone cement failures, large flaws or voids in vivo can lead to a rapid, unstable fracture, pores in the PMMA mass have a clear influence on a propagating crack, and wear of the fracture surfaces occurs, and may produce PMMA debris, exacerbating bone destruction.

Aged↗
PubMed1988

Two-stage reimplantation of septic total knee arthroplasty. Report of three cases using an antibiotic-PMMA spacer block.

The management of an infected total knee implant is a major challenge to the orthopaedic surgeon. This article reviews the use of antibiotic-PMMA spacer block in two-stage reimplanation of septic total knee arthroplasties. In addition to serving as an antibiotic delivery system between the time of component removal and reimplantation, the antibiotic-impregnated spacer block imparts mechanical stability to the joint and decreases the morbidity during the period before reimplantation. This temporary "interposition arthroplasty" facilitates the patient's ambulation and also simplifies dissection at the time of reimplantation. Furthermore, osteoporotic bone at the time of resection becomes firm, good-quality bone by the time of reimplantation.

Aged↗
PubMed1985

The use of epidural steroids in the treatment of lumbar radicular pain. A prospective, randomized, double-blind study.

Seventy-three patients with lumbar radicular pain syndromes were treated in a prospective, randomized, double-blind fashion with either seven milliliters of methylprednisolone acetate and procaine or seven milliliters of physiological saline solution and procaine. All patients had radiographic confirmation of lumbar nerve-root compression, consistent with the clinical diagnosis of either an acute herniated nucleus pulposus or spinal stenosis. No statistically significant difference was observed between the control and experimental patients with either acute disc herniation or spinal stenosis. Long-term follow-up, averaging twenty months, failed to demonstrate the efficacy of a second injection of epidural steroids administered to the patients whose pain did not respond within twenty-four hours to an injection of either eighty milligrams of methylprednisolone acetate combined with five milliliters of 1 per cent procaine or two milliliters of sterile saline combined with five milliliters of 1 per cent procaine. Therefore, a decision to use epidural steroids must be made with the realization that we failed to demonstrate its clinical efficacy in this study and that reports of serious complications of this procedure have been published.

Adrenal Cortex Hormones↗
PubMed1984

A study of computer-assisted tomography. II. Comparison of metrizamide myelography and computed tomography in the diagnosis of herniated lumbar disc and spinal stenosis.

One hundred twenty-two patients with surgically confirmed pathology consisting of either herniated lumbar disc, spinal stenosis, or both were included in this investigation. For each of these patients, preoperative metrizamide myelography and computerized tomography were performed. Each myelogram and CT scan was read blindly so that the neuroradiologist interpreting the study had no knowledge of the patient's surgical pathology, clinical examination, nor any knowledge of the interpretation of the other preoperative test. A painstaking attempt was made to describe precisely both the exact nature of the preoperative myelogram and CT scan interpretations. The correlations between the preoperative interpretation of each test and the observed surgical findings then were analyzed statistically. Based upon this analysis, myelography was found to be more accurate than computed tomography in the diagnosis of herniated lumbar disc (83% vs. 72%). In the diagnosis of spinal stenosis, myelography was slightly more accurate than computed tomography (93% vs. 89%). Based upon the results of this study, the authors conclude that metrizamide myelography is more accurate than computed tomography in the diagnosis of both herniated lumbar disc and spinal stenosis and remains the diagnostic study of choice for these conditions. Furthermore, metrizamide myelography gives the added advantage of visualizing the thoracolumbar junction and, thus, affords the opportunity to diagnose occult spinal tumors.

False Negative Reactions↗