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Biomedical subjects

W H Harris

Publications and source records attributed to W H Harris.

At least 253 records · Page 14Linked to original sources
PubMed1987

Total hip reconstruction using frozen femoral head allografts in patients with acetabular bone loss.

Major acetabular bone loss associated with failed total hip replacements can be managed successfully using frozen femoral heads as structural allografts during revision surgery. In 29 cases followed for an average period of 3.9 years, all of the grafts showed radiographic evidence of union. Five hips showed clinical or radiographic evidence for acetabular loosening. Three of these hips required reoperations for symptomatic loosening. In two of these, sufficient bone stock was present to permit another revision without further bone grafting. Twenty-five of the remaining 26 hips were functioning satisfactorily with a mean Harris score of 84 points. In view of the major bone loss following multiple previous operative procedures in these young patients, the results of revisions using structural femoral head allografts were clearly superior to those with resection arthroplasty, the most likely alternate solution. Graft resorption, lack of posterior coverage, and incomplete cement mantle contributed to the failures.

Acetabulum↗
PubMed1987

Survey of prophylaxis against venous thromboembolism in adults undergoing hip surgery.

Venous thromboembolic disease (VTED) is the most common and potentially the most serious immediate postoperative complication of hip surgery. Prophylaxis of VTED remains controversial and its practice is widely variable. Since the last survey of VTED prophylaxis as practiced by American orthopedists, published in 1974, the literature has expanded tremendously and the number of orthopedists has doubled. The authors surveyed 10% of American orthopedists and the chiefs of training programs and/or major teaching hospitals to assess current practices. The average practicing orthopedist responding was 44-years-old and had performed 17.6 total hip arthroplasties and treated operatively 30.6 hip fractures per year during the last five years. The average responding chief surgeon, was 49 years old and had performed 49 total hip arthroplasties and treated operatively 20.5 hip fractures per year during the last five years. Most surgeons use pharmacologic prophylaxis or external pneumatic compression for total hip arthroplasty patients (84.4%) and hip fracture patients (74%). Warfarin has been tried and abandoned by 50% of all respondents, largely because of bleeding complications. Aspirin was the most popular agent. However, more than 25% of the respondents stated that at least one of their patients who had elective total hip arthroplasties had died of pulmonary embolism during the last five years.

Adult↗
PubMed1987

Further follow-up on socket fixation using a metal-backed acetabular component for total hip replacement. A minimum ten-year follow-up study.

In 1982, Harris and White reported the data after a minimum five-year follow-up of fifty-three total hip replacements in forty-seven patients in whom a cemented metal-backed acetabular component had been used. There actually had been fifty-four total hip replacements in fifty-three hips, as in one hip a revision was done for a traumatic disruption of the initial acetabular component that occurred two months after the first insertion. Six of the fifty-four operations did not qualify for inclusion in this ten-year follow-up study, including four operations in three patients who had died before that time. The remaining forty-eight hips have been followed for ten to 13.5 years (mean, 11.3 years). With one exception, the ages of the patients at the time of the index operation ranged from seventeen to fifty years (mean, forty-one years). Six (12.5 per cent) of the forty-eight hips required revision because of symptomatic aseptic loosening of the acetabular component. In addition, two acetabular components, although they were not loose, were revised concomitantly with revision of the femoral component because of the presence of radiolucent lines at the cement-bone interface of the acetabular implant. One other acetabular component that was not loose was revised because of unexplained pain, one was removed because of sepsis, and for one only the polyethylene liner was exchanged because of damage to the polyethylene when the weld holding the femoral head to the femoral neck failed. Nine additional hips (19 per cent), although they were not revised, showed radiographic evidence of migration, and one (2 per cent) showed radiographic evidence of impending failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetabulum↗
PubMed1987

A study of intrusion characteristics of low viscosity cement Simplex-P and Palacos cements in a bovine cancellous bone model.

Aseptic loosening is the most common long-term complication of cemented total hip arthroplasties (THA). The functional longevity of these implants depends on the bone-cement interface. The influence of cement injection pressure, type of cement, ambient temperature, chilling of the monomer, and centrifugation of cement-on-cement intrusion depth was investigated in specimens of bovine cancellous bone. In order to validate the bovine model for comparative purposes relative to use in man, a linear relationship between human and bovine cancellous bone was first demonstrated for various porosities and cement intrusion depth. Three cements (Low Viscosity Cement [LVC], Simplex-P, and Palacos) were intruded at three different pressures (20, 40, and 60 PSI) at the same ambient temperature and relative humidity into commercially prepared plugs of bovine cancellous bone. Cement intrusion depth was proportional to injection pressure for all three cements, but was significantly different for each cement at a given pressure. At 20, 40, and 60 PSI, Palacos had a cement intrusion depth of 1.4, 2.4, and 2.8 mm respectively, while the figures for Simplex-P were 2.2, 4.2, and 5.0 mm, and for LVC were 8.0, 12.0, and 14.6 mm. Ambient temperature had an inverse relationship with cement intrusion depth for all three cements given the same experimental conditions. Chilling the monomer increased the intrusion of Simplex-P to 5.8, 8.2, and 12.7 mm at 20, 40, and 60 PSI injection pressure respectively. Simplex-P intrusion depth was not modified by cement centrifugation at any of the three injection pressures tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Current status of noncemented hip implants.

Recently the operative techniques, instrumentation, design, and material properties of bony ingrowth total hip replacement have been greatly improved. I prefer a hemispherical acetabular component fixed with screws going through the metal shell. The titanium mesh allows microinterlock with new bone, and macrointerlock is obtained by adding bone graft into the unused screw holes. The femoral component, made of Tivanium with titanium mesh attached to it by a new process called diffusion bonding, retains superalloy fatigue strength characteristics. An intimate press fit is assured by the specific operative technique, and both the fiber mesh and the collar provide proximal stress transfer. The design affords a nondestructive method for removal if necessary. The short-term clinical results are promising; most patients function as well as with cemented total hip replacement. The incidence of thigh pain has been significantly reduced since prior reports of cementless total hip replacement; however, a few patients still have thigh pain. The results in revision surgery are also promising, but as in cemented total hip replacement, the functional capacity of revision cases is usually lower than primary cases. There is an increased capacity to correct complex and difficult acetabular problems with this acetabular component. Obviously, long-term data are needed to establish the behavior of these implants over the immediate and long term.

Adult↗
PubMed1986

Formation of a synovial-like membrane at the bone-cement interface. Its role in bone resorption and implant loosening after total hip replacement.

Histologic evaluation of tissue surrounding the loosened components after joint replacement reveals the presence of a synovial-like lining adjacent to the polymethyl methacrylate cement. The tissue is heavily infiltrated with particulate cement as well as polyethylene associated with a foreign body-type giant cell reaction. That this tissue response may be responsible for the bone lysis associated with loosening is suggested by the demonstration of high prostaglandin E2 levels and enhanced bone resorbing activity in the tissue culture medium of fragments from this membrane.

Arachidonic Acid↗
PubMed1986

Contact pressures in the human hip joint measured in vivo.

The pressures on human articular cartilage have been measured in vivo. An instrumented femoral head prosthesis that telemeters interarticular pressure at 10 discrete locations 253 times per second was implanted in apposition to natural acetabular cartilage. Data were acquired during surgery, recovery, rehabilitation, and normal activity, for longer than 1 year after surgery. Pressure magnitudes were synchronized with body-segment kinematic data and foot-floor force measurements so as to locate transduced pressure areas on the natural acetabulum and correlate movement kinematics and dynamics with local cartilage pressures. The data reveal very high local (up to 18 MPa) and nonuniform pressures, with abrupt spatial and temporal gradients, that correlate well both in magnitude and distribution with in vitro data and computer simulations of synovial joint mechanics. Peak pressures in vivo are, however, considerably higher than pressures measured in vitro under the putative forces experienced by the joint in life, particularly in normal movements where cocontraction occurs in agonist and antagonist muscles across the hip joint. Thus, extant gait-analysis studies which apply inverse Newtonian calculations to infer joint forces establish the lower limit on such forces, since such analyses include only the net muscular torques about the joint and cannot account for the contribution of the increment in joint force due to muscular cocontraction. Our data also contribute to the understanding of normal synovial joint tribology and the possible role of mechanical factors in the deterioration evident in osteoarthritis. Further, design criteria for both partial and total hip replacement prostheses and specific aspects of rehabilitation protocols following hip surgery (e.g., the extent to which crutches and canes unload the hip joint) warrant reconsideration in light of the extraordinary high pressures measured during the activities of daily living.

Biomechanical Phenomena↗
PubMed1986

The receptors responsible for heat production in brown adipose tissue in the young rabbit.

It is known that adrenergic agonists stimulate thermogenesis in the brown fat of the young rabbit but the receptors responsible for mediating the response have not been identified. The infusion of either noradrenaline or isoproterenol (1-2 micrograms . kg-1 X min-1) produced an increase in subcutaneous temperature (0.93 +/- 0.15 and 1.22 +/- 0.10 degrees C, respectively over the interscapular brown fat. At low doses (0.4 microgram . kg-1 X min-1) only isoproterenol was effective. The thermogenic response to isoproterenol was blocked by atenolol, a beta 1-adrenergic antagonist. Neither salbutamol or terbutaline, both beta 2-agonists, produced a temperature increase. Collectively, these data suggest that stimulation of beta 1-adrenoceptor is primarily responsible for the thermogenic activity of brown fat in the rabbit. However, it was found that 53% of the increase in temperature could be blocked by prazosin, an alpha 1-antagonist. Phentolamine was not effective as a blocker. Although a maximal brown fat thermogenic response can be achieved by stimulating the beta-adrenoceptors, the alpha-adrenoceptors appears to play at least an auxiliary role in young rabbit.

Adipose Tissue, Brown↗
PubMed1986

The noradrenaline content and innervation of brown adipose tissue in the young rabbit.

This work examined the noradrenaline content of brown adipose tissue, the metabolic response to endogenous noradrenaline released during tyramine infusion, and the innervation of brown fat at the electron microscopic level in the young rabbit. The noradrenaline content (ng/g) of the interscapular and cervical fat deposits ranged from 256 +/- 51 to 343 +/- 59 and 399 +/- 18 to 694 +/- 92, respectively, in four groups of rabbits (1-2, 7-8, 12-13, and 25-27 days of age). There was considerable variation amongst animals in each age group, but no evidence of a major increase or decrease in noradrenaline content during the first 4 weeks of life. Intravenous infusion of tyramine (100 micrograms X kg-1 X min-1) increased plasma noradrenaline concentration, oxygen consumption, and blood flow to brown fat. Thus noradrenaline released from endogenous sites, as well as injected noradrenaline, will initiate the thermogenic response of brown fat. Ultrastructurally, unmyelinated axons that were not organized in a fascicle were observed adjacent to the adipocytes in the late gestation fetus. By 1 week of age of axons were surrounded by Schwann cell cytoplasm which formed a fascicle. However, no evidence of myelination was found up to 21 days of age. Collectively, the data indicate that the brown adipocyte is fully responsive at 1-2 days of age even though myelination of the nerves is incomplete, and that the incomplete development of the sympathetic nerves at birth is not a factor in the synthesis of noradrenaline in the very young rabbit. In addition, brown fat of the newborn rabbit is not as thermogenically active as the brown fat of the cold-acclimated rat.

Adipose Tissue↗
PubMed1986

Massive allografting for severe failed total hip replacement.

We are presenting the cases of five patients that illustrate the uses of large, frozen bone and osteoarticular allografts in dealing with severe structural deficiency about the hip joint associated with prior failed total hip replacement. The status of the grafts was assessed at a minimum follow-up of twenty-four months (average, thirty months). In four patients extensive grafts in the proximal part of the femur in conjunction with total hip-replacement components were used, and in the fifth patient a matched whole-joint transplant of the proximal part of the femur and the acetabulum was employed. The short-term clinical advantage of these massive grafts is clear, but the long-term results are uncertain.

Adult↗
PubMed1986

Localized osteolysis in stable, non-septic total hip replacement.

We are reporting four cases of extensive, localized bone resorption adjacent to a rigidly anchored, cemented total hip replacement. None of these hips showed evidence of infection on clinical, bacteriological, or pathological evaluation. The tissue from the regions of osteolysis showed sheets of macrophages and foreign-body giant cells invading the femoral cortices. Abundant methylmethacrylate particulate debris was present in the tissues, but polyethylene wear debris was absent. The histological appearance of this tissue resembled that reported about loosened total hip implants with the exception of the synovial-like layer at the cement surface. The cases reported here show that aggressive bone lysis may occur around stable cemented total hip arthroplasties without the presence of sepsis or malignant disease.

Adult↗
PubMed1986

A system for trochanteric osteotomy and reattachment for total hip arthroplasty with a ninety-nine percent union rate.

In certain circumstances osteotomy of the greater trochanter in total hip arthroplasty is of benefit. To attack the problem of nonunion following trochanteric osteotomy, the authors apply several different wiring techniques. To quantify the efficacy of these approaches, they have reviewed 804 consecutive total hip arthroplasties in which the greater trochanter was osteotomized, including 725 primary total hip arthroplasties. Ninety-nine percent of the trochanters united. Among the 79 revision cases, the trochanter united in every case. The use of two independent vertical wires with one transverse wire was the preferred technique.

Adolescent↗
PubMed1986

Proliferation of myogenic cells in the diaphragm of the fetal rabbit.

Diaphragms obtained from 40 fetal rabbits at gestational ages of 20, 22, 25 and 30 days were examined by light and transmission electron microscopes. The percentage of myogenic cells undergoing mitosis was calculated by counting mitotic nuclei in 1 micron sections. At 20 and 22 days gestation, myogenic cells (myoblasts and satellite cells) were actively proliferating with 2.66 +/- 0.41% (n = 15) and 2.18 +/- 0.20% (n = 23), of the cells in division, respectively. The myogenic cells undergoing mitosis appeared to be of both myoblasts and satellite cells at these stages of the development. The myotubes on day 20 of gestation contained a large number of lipid droplets and an abundance of glycogen particles which were reduced by day 22 of gestation. The mitotic rate on day 25 of gestation was reduced to 1.16 +/- 0.11% (n = 28). The muscle fibers were well differentiated at this stage and the majority of the dividing cells were considered to be satellite cells. In diaphragms from the full term fetuses (day 30), the mitotic rate was reduced to 0.31 +/- 0.05% (n = 24). It was suggested that myoblasts of the fetal rabbit diaphragm proliferated for the myotube formation during the earliest stage of the development (day 20 of gestation) and then the number of satellite cells increased after day 22 of gestation. Growth of the organ after day 25 of gestation appeared to be mostly due primarily to the hypertrophy and differentiation of the muscle fibers rather than proliferation of myoblasts.

Animals↗
PubMed1986

Loosening of the femoral component after use of the medullary-plug cementing technique. Follow-up note with a minimum five-year follow-up.

Of the 171 total hip replacements reported on previously that had had a minimum length of follow-up of two years, 117 replacements in 104 patients were analyzed at a minimum of five years postoperatively (average, seventy-four months; range, sixty to ninety-four months) to assess the rate of loosening of the femoral component. At the time of cementing of the femoral component, the medullary canal had been plugged with a bolus of bone cement and then filled with doughy Simplex-P methylmethacrylate in a retrograde fashion using a cement gun. The femoral components, made of a chromium-cobalt alloy, had a rectangular cross-sectional shape to the stem and a medial collar. Three categories of loosening were used: definite (requiring radiographic evidence of migration of the component or the cement), probable (requiring evidence of a complete radiolucent zone at the bone-cement interface on one radiograph or more), and possible (a radiolucent zone at the cement-bone interface of more than 49 per cent but less than 100 per cent on one radiograph or more). One femoral component had been removed for aseptic loosening at another hospital, leaving the patient with a resection arthroplasty. One other (1.7 per cent) was definitely loose. No femoral component was categorized as probably loose, and only two were possibly loose.

Adult↗
PubMed1986

Femoral head autografting to augment acetabular deficiency in patients requiring total hip replacement. A minimum five-year and an average seven-year follow-up study.

Adults who have osteoarthritis that is secondary to mild congenital dysplasia can be treated with total hip replacement using customary techniques. Those who have severe acetabular dysplasia or total congenital dislocation usually require augmentation of acetabular bone stock in order to carry out the total hip replacement. We reviewed the results of forty-seven total hip replacements in thirty-eight patients (age range, sixteen to sixty-eight years; average age, forty-seven years) who required autogenous grafting with bone from the femoral head for severe acetabular deficiency. The average length of follow-up was 7.1 years (minimum, five years). All grafts united. The average preoperative Harris hip rating was 46 points and the average postoperative rating was 74 points. Five hips (approximately 10 per cent) had a failure that required reoperation; four hipshad aseptic loosening of the acetabular component and in the fifth sepsis developed after a reoperation to reattach the greater trochanter. For the remaining forty-two hips, the average postoperative Harris hip rating was 78 points. Six additional sockets (approximately 15 per cent) were definitely loose by radiographic criteria, making a total of ten hips (approximately 20 per cent) with definite aseptic loosening of the acetabular component. The major factors that contributed to this aseptic loosening were complexity of the surgical procedure, necessity for a graft, lack of a small-sized metal-backed acetabular component, young age, obesity, lack of posterior support, and resorption of the graft. Dislocation was common, occurring in five (approximately 10 per cent) of the hips.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetabulum↗
PubMed1986

Etiology of osteoarthritis of the hip.

More than 90% of patients with so-called primary or idiopathic osteoarthritis of the hips in whom sufficient data were available to make an assessment of the normality of the hip joint at the cessation of growth clearly showed demonstrable abnormalities in the hip joint. The most common are mild acetabular dysplasia and/or pistol grip deformity. This latter deformity is associated with mild slipped capital femoral epiphysis (recognized or unrecognized at the time), Legg-Perthes' disease (recognized or unrecognized at the time), multiple epiphyseal dysplasia, spondyloepiphyseal dysplasia, and/or the presence of an intraacetabular labrum, as well as, in certain instances, acetabular dysplasia. When these abnormalities are taken in conjunction with the detection of other metabolic abnormalities that can lead to osteoarthritis of the hip and which may not be recognized readily, such as hemochromatosis, ochronosis, calcium pyrophosphate disease, and monarticular rheumatoid arthritis, it seems clear that either osteoarthritis of the hip does not exist at all as a primary disease entity or, if it does, is extraordinarily rare.

Acetabulum↗
PubMed1986

Factors controlling optimal bone ingrowth of total hip replacement components.

The major factors dealing with optimization of bony ingrowth for total hip replacement have been shown by experimental and limited clinical experience to be apposition, pore size, rigid initial fixation, the type of bone surface, weight bearing, biocompatibility, remodeling, bone grafting, other forms of stimuli, and the distinctions between the human response and the response of the experimental animals.

Animals↗