Biomedical subjects

W H Harris

Publications and source records attributed to W H Harris.

At least 37 records · Page 2Linked to original sources

PubMed2000

20-year experience with cemented primary and conversion total hip arthroplasty using so-called second-generation cementing techniques in patients aged 50 years or younger.

We present the 20-year experience of 47 hips in 40 patients aged 50 years or younger with cemented primary total hip arthroplasty using second-generation femoral cementing techniques. Average follow-up duration in the 23 patients living at least 17 years was 18.2 years. Overall, 18 hips (38%) had components revised or removed for any reason, at an average duration of 12.6 years. Every revision or reoperation involved removing the acetabular component. Of these 18 acetabular components, 15 (32%) were revised for aseptic loosening. Eleven additional acetabular components were loose by radiographic criteria at final follow-up, yielding prevalence of aseptic acetabular loosening (55%). Four femoral components (8%) were revised for osteolysis without loosening, and 3 (6%) were revised for aseptic loosening. Femoral osteolysis, with or without component loosening, led to revision in 5 ( 11%) hips compared with 6% for aseptic loosening alone. Osteolysis was the primary problem leading to acetabular and femoral component revision in this series of people < or = 50 years old over the first 20 years after the index operation.

Adult↗

PubMed2000

Acetabular revision arthroplasty using so-called jumbo cementless components: an average 7-year follow-up study.

The optimal technique for acetabular revision surgery in the face of major bone stock deficiency remains controversial. One subset of these problem cases consists of hips that are amenable to reconstruction using a large, hemispherical cementless acetabular component, the so-called jumbo acetabular component. We report the intermediate-term experience of 24 hips in 24 patients who underwent an uncemented acetabular revision using a hemispherical acetabular component of > or = 66 mm diameter. In 16 hips, the femoral component was replaced as well. Of the 18 hips in patients alive after 5 years, 15 were assessed at a mean follow-up of 7.0 years (range, 5.0-10.3 years). The mean final Harris Hip Score was 86 points (range, 45-100 points). No acetabular component had been revised, and none were loose radiographically. In this difficult group, a bimodal distribution resulted. The complication rate was high. In those without infection, the results were excellent.

Acetabulum↗

PubMed2000

A stem design change to reduce peak cement strains at the tip of cemented total hip arthroplasty.

A series of 3-dimensional finite element models was created to assess different designs of the tip of the stems of cemented femoral components of total hip arthroplasty that would decrease the peak axial tensile cement strains developed near the tip. Features of stem design that would facilitate positioning the femoral component in a neutral position centered in uniform cement mantle of adequate thickness also were evaluated. These studies showed that a stem that had a narrow tip profile that would accept an externally applied polymethyl methacrylate centralizer shaped similar to a napkin ring and had a gradual transition zone to join the body of the implant achieved these objectives. Such a combination resulted in the reduction of the peak axial strains to less than half the magnitude of the peak strains around a conventional tip (830 vs 1,868 microstrain). The reduction in peak axial strains was to one third the magnitude of the strains developed adjacent to a stem with a hole drilled into the tip to accept the commonly used fin-type polymethyl methacrylate centralizer (830 vs 2,466 microstrain). These goals were achieved because a stem that is designed to accept a napkin ring-style centralizer i) has a lower bending stiffness at the tip of the implant, ii) allows room for a thicker cement mantle, and iii) avoids creating a stress riser adjacent to the edge of the drill hole. The peak cement strains adjacent to a stem of this design are well below the endurance limit of cement as long as the transition zone where the narrow tip meets the body of the implant is gradual.

Biomechanical Phenomena↗

PubMed2000

Acetabular revision after failed total hip arthroplasty in patients with congenital hip dislocation and dysplasia. Results after a mean of 8.6 years.

BACKGROUND: Revision of a total hip arthroplasty in a patient who has had congenital hip dysplasia or dislocation is often more difficult than a standard revision operation. The purpose of this study was to assess the efficacy and complications of use of a cementless hemispherical acetabular component for revision of an acetabular component of a failed total hip replacement in patients whose initial problem was arthritis secondary to congenital dislocation or dysplasia. The mean duration of follow-up was approximately eight years. METHODS: We reviewed a consecutive series of sixty-one hips in fifty-three patients who underwent a cementless acetabular revision with use of a hemispherical acetabular component, with or without concurrent femoral revision. Data were collected prospectively. The mean age of the patients at the time of the index operation was fifty-six years. A mean of 1.9 ipsilateral hip operations had been performed previously. Thirty-nine hips (64 percent) had a so-called high hip center prior to the index revision. With one exception, the uncemented acetabular component was fixed with screws. Fifty-one acetabular components were placed with so-called line-to-line fit, and ten were oversized by one to three millimeters. In thirty-eight hips, the femoral component was revised as well. Twenty-nine femora were reconstructed with use of a cemented device, and nine were revised with an uncemented patch-porous-coated femoral stem (a stem on which the porous coating appears in patches). RESULTS: Four patients (five hips) died prior to the five-year minimum follow-up interval. With the exception of one hip treated with resection arthroplasty because of deep infection, none of the hips in these deceased patients had been revised or had a loose component. One living patient (one hip) had a resection arthroplasty, and one additional patient (two hips) had both stable acetabular components rerevised at the time of femoral rerevision at another institution because of loosening and osteolysis. One patient refused to return for follow-up, but the components had not been revised. The remaining fifty-two hips in forty-six patients were followed for a mean of 8.6 years (range, 5.0 to 12.7 years). The mean Harris hip score was 80 points (range, 56 to 100 points) at the time of the latest follow-up. No acetabular component had been revised, although two had migrated. No other acetabular component was loose according to our radiographic criteria. Thus, the mechanical failure rate on the acetabular side was 3 percent (two of sixty-one) for the entire series and 4 percent (two of fifty-two) for the patients who had been followed for a mean of 8.6 years. On the femoral side, the mechanical failure rate was 3 percent (one of twenty-nine) for the cemented stems and six of nine for the uncemented patch-porous-coated stems. CONCLUSIONS: Of the approaches used in this difficult series of patients requiring revision, the hybrid arthroplasty (a cementless acetabular component and a cemented femoral component) yielded overall good results after an intermediate duration of follow-up.

Acetabulum↗

PubMed1999

Effect of c-erbB(2) and estrogen receptor status on survival of women with primary breast cancer treated with adjuvant cyclophosphamide/methotrexate/fluorouracil.

We have investigated the relationship between c-erbB(2) status, estrogen receptor (ER) status and outcome in 274 women with node-positive breast cancer who, following excision and axillary clearance, were randomized to receive either 6 cycles of cyclophosphamide/methotrexate/fluorouracil (CMF) (n = 129) or no such treatment (n = 145). Follow-up data (median 13.3 years) were available on all patients. CMF improved relapse-free and overall survival of all women. The greatest benefit was seen in women with ER-negative tumors; the median overall survival of those given CMF was 11.6 years compared with only 2 years for the control group. For the women with ER-positive tumors the median overall survival of the CMF-treated women was 11.3 years compared with 7.7 years in the control group. When benefit from CMF was examined in relation to c-erbB(2) status, the women with c-erbB(2)-negative tumors who received CMF had a median overall survival of 12.7 years compared with only 7.3 years for the c-erbB(2)-negative women in the control group. The improvement in survival was less marked in the women with c-erbB(2)-positive tumors; median overall survival was 6.1 years for those who received CMF compared with 4.4 years for women in the control group. All women benefited from adjuvant CMF chemotherapy, those with ER-negative tumors benefiting the most. Int. J. Cancer (Pred. Oncol.) 84:354-359, 1999.

Adult↗

PubMed1999

Methylation of the BRCA1 promoter region in sporadic breast and ovarian cancer: correlation with disease characteristics.

Reduced expression of BRCA1 has been reported in sporadic breast cancer, although the mechanisms underlying this phenomenon remain unclear. Abnormal methylation leading to silencing of tumour suppressor genes has been implicated in tumorigenesis in a wide range of sporadic cancers. Therefore, we sought to determine the frequency of methylation within the BRCA1 promoter region in a large group of sporadic invasive breast (n =96) and ovarian (n = 43) carcinomas using Southern analyses. Overall, methylation was detected in 11% of breast cancer cases and in 5% of ovarian tumours. Methylation of the BRCA1 promoter region was strongly correlated with lack of estrogen and progesterone receptor expression. It is clear from the frequency of abnormal methylation of the BRCA1 promoter region, that this cannot be the sole mechanism mediating the reduced expression of BRCA1 that has previously been reported to occur in the majority of invasive sporadic breast tumours. Nevertheless this study suggests that abnormal methylation of the BRCA1 promoter may be important in tumorigenesis in a subset of sporadic breast and ovarian cancers.

Adult↗

PubMed1999

The biological and prognostic significance of cell polarity and E-cadherin in grade I infiltrating ductal carcinoma of the breast.

Grading of breast cancer based on the modified Scarff, Bloom, and Richardson system provides invaluable prognostic information. Recent evidence suggests that most tumours do not usually progress between grades and that groups of tumours within each grade are biologically distinct. This study has explored one potential aspect of biological tumour heterogeneity within grade by examining the relationship between cell polarity, the cell adhesion molecule E-cadherin, a major effector of cell polarity, and outcome, in 149 grade I infiltrating ductal breast carcinomas. Polarity was evaluated by studying the degree to which three features of polarized epithelial cells-nuclear ordering, basal positioning of nuclei within cells, and apical snouting/blebbing-were present in these tumours. E-cadherin expression was investigated using the antibody HECD-1. A low degree of tubule formation was correlated with poor nuclear ordering ( p< 0.01). The three histological features-nuclear ordering, basal nuclei, and apical blebbing-were all correlated with each other (all p< 0.0001). Polarity measurements did not correlate with survival. E-cadherin expression did not correlate with polarity and negative tumours were still able to form tubules. Surprisingly, strong E-cadherin immunostaining correlated with poor survival, tumour size, and nodal status. On univariate parametric (Weibull) survival models, high E-cadherin scores and tumour size were both significant predictors of survival in this group.

Adult↗

PubMed1999

Reduced bone stress as predicted by composite beam theory correlates with cortical bone loss following cemented total hip arthroplasty.

Clinical and experimental evidence suggest that periprosthetic bone loss following total hip arthroplasty is caused in part by stress-shielding. Changes in bone stress in the proximal femur following implantation can be estimated with use of composite beam theory. We hypothesized that the degree of stress-shielding predicted by beam theory correlates with the magnitude of bone loss following cemented total hip arthroplasty. We analyzed cross sections from the proximal femur of 13 patients who had undergone unilateral cemented total hip arthroplasty. A matching implant was inserted contralaterally, and the cross-sectional properties of the implant and bone and the bone density were determined. Bone loss was calculated on the basis of differences between contralateral (control) and ipsilateral (remodeled) sections and correlated to several beam-theory parameters calculated from the control sections: implant rigidity, bone rigidity, ratio of implant to bone rigidity, and predicted decrease in bone stress. All parameters except implant rigidity were significantly correlated with bone loss (p < 0.05). Parameters that included implant and bone properties were more strongly correlated with bone loss than were those based on bone properties alone. The predicted decrease in bone stress explained 50-60% of the variance in bone loss. The data also indicated that patients were not likely to lose substantial amounts of bone unless the reduction in bone stress exceeded a threshold value. Although limited by a small and heterogeneous sample, these results indicate that beam-theory predictions correlate with the degree of femoral resorption and should be investigated further as a means to identify patients at high risk for bone loss.

Arthroplasty, Replacement, Hip↗

PubMed1999

Unified wear model for highly crosslinked ultra-high molecular weight polyethylenes (UHMWPE).

Crosslinking has been shown to improve the wear resistance of ultra-high molecular weight polyethylene in both in vitro and clinical in vivo studies. The molecular mechanisms and material properties that are responsible for this marked improvement in wear resistance are still not well understood. In fact, following crosslinking a number of mechanical properties of UHMWPE are decreased including toughness, modulus, ultimate tensile strength, yield strength, and hardness. In general, these changes would be expected to constitute a precursor for lower wear resistance, presenting a paradox in that wear resistance increases with crosslinking. In order to understand better and to analyze this paradoxical behaviour of crosslinked UHMWPE, we investigated the wear behavior of (i) radiation-crosslinked GUR 1050 resin, (ii) peroxide-crosslinked GUR 1050 resin and (iii) peroxide-crosslinked Himont 1900 resin using a bi-directional pin-on-disk (POD) machine. Wear behavior was analyzed as a function of crystallinity, ultimate tensile strength (UTS), yield strength (YS), and molecular weight between crosslinks (Mc). The crosslink density increased with increasing radiation dose level and initial peroxide content. The UTS, YS, and crystallinity decreased with increasing crosslink density. While these variations followed the same trend, the absolute changes as a function of crosslink density were different for the three types of crosslinked UHMWPE studied. There was no unified correlation for the wear behavior of the three types of crosslinked UHMWPE with the crystallinity, UTS and YS. However, the POD wear rate showed the identical linear dependence on Mc with all three types of crosslinked UHMWPEs studied. Therefore, we have strong evidence to propose that Mc or crosslink density is a fundamental material property that governs the lubricated adhesive and abrasive wear mechanisms of crosslinked UHMWPEs, overriding the possible effects of other material properties such as UTS, YS and crystallinity on the wear behavior.

Biocompatible Materials↗

PubMed1999

The Harris-Galante uncemented femoral component in primary total hip replacement at 10 years.

Eighty-eight primary femoral reconstructions in 80 patients were performed with the Harris-Galante uncemented femoral stem by 1 surgeon between March 1984 and December 1987. Seventy-seven femoral components in 72 patients were followed for an average 126 months or until femoral revisions. The average age at operation was 54 years (range, 30-70 years). Fifty-two patients were men, and 20 were women. The present article documents the incidence of femoral osteolysis and femoral revision in this series of this type of femoral component at an average of 10 years. Fifteen femoral components (15 of 77, 19%) were revised, 14 (14 of 77, 18%) for aseptic loosening, osteolysis, or fracture through osteolysis. The remaining 62 femoral components were functioning well (average Harris Hip Score 89 points), but 7 (11%) were loose, and 32 (52%) had femoral endosteal lysis. Overall, 19 (25%) were revised or loose, and 46 (46 of 77, 60%) had lysis. The high incidence of femoral lysis and aseptic loosening with this early design of uncemented femoral stem continues to increase at 10-year follow-up.

Adult↗

PubMed1999

Fixation, polyethylene wear, and pelvic osteolysis in primary total hip replacement.

A multicenter retrospective review was performed analyzing 1081 primary total hip replacements in 944 patients using the Harris Galante-I cementless acetabular component with screw fixation. All patients were followed up for a minimum of 5 years with a mean followup of 81 months. Linear polyethylene wear averaged 0.11 mm/year (range, 0-0.86 mm/year). Pelvic osteolysis was seen in 25 patients (2.3%). Migration of the acetabular component was seen in four hips. A subgroup of patients was reanalyzed at a minimum followup of 10 years. The mean linear polyethylene wear rate remained 0.11 mm/year. In this group, only one socket had migrated. There was an association between wear rate and age. On average, younger patients had higher wear rates. The risk for having pelvic osteolysis develop and the need for revision surgery also was age-related. Twenty-two percent of hip replacements (15 hips) in patients younger than 50 years of age at the time of their index operation had pelvic osteolysis develop. In contrast, for patients older than 50 years of age at the time of surgery only 7.8% (eight hips) had osteolysis of the pelvis develop. For patients older than 70 years of age at the time of primary total hip replacement, none had pelvic osteolysis develop.

Adolescent↗

PubMed1999

The role of acetabular component screw holes and/or screws in the development of pelvic osteolysis.

Anecdotal reporting of osteolysis around cementless modular acetabular components with holes through the metal shell and/or iliac fixation screws has raised concern that such designs may generate excessive particulate debris and/or permit direct access of particulate debris to iliac bone. To address this issue, incidence data are reported on 513 total hip replacements from six different single-surgeon series of total hip arthroplasties performed with six different porous ingrowth acetabular components. With follow-up ranging from 40 to 108 months, a total of 45 pelvic osteolytic lesions were observed (8.8 per cent). Pelvic osteolysis was seen nearly as frequently in the ischium and pubis (21 lesions) as it was in the ilium (24 lesions). It was not possible to explain ischial and pubic osteolysis by holes and/or screws through the acetabular component shell. There was no direct correlation between the presence of screw holes or screws and the incidence of pelvic osteolysis. The incidence of pelvic osteolysis around modular components with holes through the shell was 4.5 per cent (14 of 313 hips). The incidence of pelvic osteolysis with solid-shell components was 15.5 per cent (31 of 200). The incidence of pelvic osteolysis around acetabular reconstructions with screws was 2.3 per cent (3 of 133). The incidence of pelvic osteolysis in reconstructions without screws was 11.1 per cent (32 of 380). The incidence of pelvic osteolysis in one-piece acetabular components (polyethylene pre-fixed in the metal shell) was 12.7 per cent (21 of 165) and the incidence of pelvic osteolysis with the modular components was 6.9 per cent (24 of 348). In each comparison, the incidence of pelvic osteolysis was actually lower in the group assumed to be at increased risk. Based on this review there does not appear to be a direct relationship between holes and/or screws through an acetabular component and the development of pelvic osteolysis. The incidence of pelvic osteolysis was associated with larger head diameters and longer follow-up. While screw holes may provide an access channel in specific cases, the present data indicate that the simple elimination of holes through the acetabular shell will not eliminate pelvic osteolysis. Regardless of other acetabular component design features, joint fluid and polyethylene wear particles from the femoral-acetabular articulation can gain access to bone behind an acetabular component via the peripheral implant-bone interface through regions without sufficient contact or tissue ingrowth. The development of pelvic osteolysis is multifactorial and includes the total volumetric wear of polyethylene as well as specific features of the acetabular component design and reconstruction technique.

Adult↗

PubMed1999

The Harris-Galante porous-coated acetabular component with screw fixation. An average ten-year follow-up study.

Two hundred and thirty-seven consecutive primary acetabular reconstructions were performed, in 213 patients, with use of a Harris-Galante porous-coated acetabular component with screw fixation between January 1984 and December 1987. Twenty-four patients (twenty-seven hips) died before a minimum duration of follow-up of eighty-four months, five patients (five hips) were too ill to return for a detailed follow-up examination at the time of the study, four patients (four hips) refused clinical and radiographic follow-up (but one of these patients had more than eighty-four months of follow-up for one side of a bilateral total hip replacement), two patients (two hips) were lost to follow-up, and two patients (two hips) refused radiographic follow-up but had adequate clinical follow-up. In addition, one patient who had had a bilateral total hip replacement had a resection arthroplasty on one side because of a late infection 115 months after the index procedure. Thus, 196 hips (83 per cent) in 177 patients were available for radiographic and clinical review after an average duration of follow-up of 122 months (range, eighty-four to 155 months). The average age of these 177 patients at the time of the operation was fifty-nine years (range, twenty-three to eighty-seven years). Eight well fixed acetabular shells (4 percent) were revised: three were revised because of dissociation of the liner in association with fractures of the tines, three were revised during revision of the femoral component, and two were revised because of retroacetabular osteolysis. In eight other hips, the acetabular liner was exchanged during revision of a loose femoral component. No acetabular component migrated, was classified as radiographically loose, or was revised because of aseptic loosening. There was no evidence of fragmentation or disruption of the titanium porous mesh of any cup. One of 528 screws broke. There were no complications associated with the insertion of the acetabular fixation screws. Osteolytic lesions were identified adjacent to nine (5 percent) of the 188 acetabular components that were in place at the time of the most recent examination. One hip, which had discontinuous osteolytic lesions in all three acetabular zones, was treated with bone-grafting around the well fixed acetabular component. Eight hips had a discontinuous radiolucent line that was 1.0 millimeter wide or less in all three zones and another two had a continuous radiolucent line that was 0.5 millimeter wide in all three zones. The average Harris hip score for the 188 hips (169 patients) that did not have revision of the acetabular shell improved from 47 points (range, 22 to 71 points) preoperatively to 89 points (range, 35 to 100 points) at the time of the latest examination. One hundred and thirty-four hips had an excellent result; twenty-six, a good result; nineteen, a fair result; and nine, a poor result. All nine hips that had a poor result were in patients who had other factors, unrelated to the acetabular component, that contributed to the low Harris hip score. In the present study, the Harris-Galante porous-coated acetabular component continued to provide excellent fixation and clinical results for most patients at an average of approximately ten years after the operation.

Acetabulum↗

PubMed1999

Primary hybrid total hip replacement, performed with insertion of the acetabular component without cement and a precoat femoral component with cement. An average ten-year follow-up study.

One hundred and twenty-one primary hybrid total hip replacements were performed in 107 patients. A titanium, porous-coated, hemispherical acetabular component was fixed with screws, and a collared, chromium-cobalt femoral stem, with a roughened surface and a thin layer of methylmethacrylate on the proximal third, was inserted with contemporary cementing techniques (that is, use of a femoral medullary plug, a cement gun, and centrifugation and pressurization of the cement). Fifteen patients (fifteen hips) died before a minimum duration of follow-up of seven years, four patients (four hips) were too ill for a detailed follow-up examination at the time of the study, and two patients (two hips) refused to be evaluated at the time of the latest follow-up. None of these twenty-one hips had had a revision or a reoperation at the time of the latest follow-up. Eighty-six patients (100 hips) were available for clinical follow-up at an average of 120 months (range, eighty-four to 153 months) and for radiographic follow-up at an average of 118 months (range, eighty-four to 153 months). The average age of the patients at the time of the index arthroplasty was sixty-five years (range, forty-five to eighty-seven years). Three acetabular components were revised because of dissociation of the liner in association with a fracture of a locking tine. One well fixed acetabular component was revised because of pelvic osteolysis, and the femoral stem in the same patient was revised because of aseptic loosening. None of the ninety-six remaining acetabular components migrated, was classified as radiographically loose, or was revised because of aseptic loosening. Osteolytic lesions were identified adjacent to five acetabular components, and one of them was treated with bone-grafting around the well fixed acetabular shell. Two hips had a continuous radiolucent line at the interface between the acetabular implant and the bone. Three femoral stems had evidence of radiographic debonding (a radiolucent line that was one millimeter wide or less between the cement and the prosthesis), and they were classified as radiographically loose despite excellent clinical results. Seven hips had osteolytic areas located in the proximal aspect of the most proximal zones of Gruen et al., and five had small osteolytic regions in more distal areas. The Harris hip score for the eighty-two patients (ninety-six hips) who did not have a revision improved from 48 points (range, 22 to 70 points) preoperatively to 92 points (range, 53 to 100 points) at the most recent follow-up examination. Eighty-one patients had no, slight, or mild pain in the hip, and they were satisfied with the clinical result. In the present study, the hybrid total hip replacement with use of the Harris-Galante acetabular component and the Precoat femoral stem continued to provide an excellent result for most patients at an average of approximately ten years after the operation.

Acetabulum↗

PubMed1999

Total hip arthroplasty with insertion of the acetabular component without cement in hips with total congenital dislocation or marked congenital dysplasia.

BACKGROUND: End-stage osteoarthritis secondary to total congenital dislocation or severe congenital dysplasia of the hip (class B or C according to the system of Eftekhar or type 2 or 3 according to the system of Hartofilakidis et al.) in adults presents special problems with regard to reconstruction of the hip. The purpose of the present study was to assess the intermediate-term results associated with the use of a porous ingrowth acetabular component for the treatment of these difficult cases. METHODS: We performed a prospective study of a consecutive series of twenty-one patients (twenty-four hips) who had had a primary total hip arthroplasty with use of a hemispherical acetabular component that was inserted without cement and fixed with screws. No patient was lost to follow-up. Three patients (four hips) died, of causes unrelated to the total hip arthroplasty, before a minimum duration of follow-up of five years. None of these patients had had revision. Of the remaining eighteen patients (twenty hips), fifteen were women and three were men. Ten hips had total dislocation, and ten had severe dysplasia. RESULTS: After an average duration of follow-up of eighty-three months (range, sixty-four to 102 months), the average Harris hip score was 90 points (range, 68 to 97 points). No patient had revision, loosening, or migration of the acetabular component; pelvic osteolysis; or a continuous radiolucent line at the mesh-bone interface of the acetabular component. The average rate of polyethylene wear was 0.08 millimeter per year (range, zero to 0.21 millimeter per year). CONCLUSIONS: The porous ingrowth acetabular component that was used in the present study functioned well at the time of the intermediate-term follow-up of this group of patients who had marked congenital dysplasia or total dislocation of the hip. The use of this component decreased the need for structural acetabular grafts. This component appears to perform as well as larger components of this design that have been assessed after similar durations of follow-up.

Adult↗

PubMed1999

High placement of an acetabular component inserted without cement in a revision total hip arthroplasty. Results after a mean of ten years.

BACKGROUND: Revision of an acetabular component in a patient who has severe periacetabular bone loss is a complex problem, particularly when there is not enough bone stock to allow placement of an acetabular component near the normal anatomical hip center. A valuable option for revision in such a situation is placement of a hemispherical shell, fixed with screws and without cement, against the superior margin of the acetabular defect. The resulting hip center is more proximal than that seen following a typical primary total hip replacement. METHODS: Forty-six hips in forty-four patients were treated consecutively, between July 1984 and February 1988, with a revision in which a hemispherical acetabular component was fixed with screws and without cement. All shells but one were placed with a so-called line-to-line fit. The procedures resulted in a so-called high hip center--that is, the center of rotation of the revised hip was located at least thirty-five millimeters proximal to the interteardrop line. The mean age of the patients at the time of the index procedure was fifty-two years (range, twenty-five to eighty-one years). The most common diagnosis for which the original arthroplasty was performed was osteoarthritis secondary to congenital hip dysplasia or dislocation (twenty-two hips). Thirty-four hips had had a high hip center before the index revision, and most patients had had a substantial limb-length discrepancy, with a mean of 1.6 centimeters of shortening on the side of the operation. In thirty-three hips, the femoral component was replaced as well, with a long-neck or calcar-replacement stem used when necessary to maintain or increase the length of the limb. RESULTS: Six patients (six hips) died before the minimum eight-year follow-up interval; none had had another revision or loosening of the revised acetabular component. Of the remaining patients, four (four hips) had the implant removed. One of them had a resection arthroplasty and one of them had a hip disarticulation because of infection after a subsequent femoral reoperation. Another had a hip disarticulation because of late infection. The fourth implant was removed because it had displaced into the pelvis at approximately six years; this was the only reoperation for aseptic loosening in the series. The remaining thirty-six hips (thirty-four patients) were followed for a mean of 10.4 years (range, 8.5 to 12.7 years). One acetabular component migrated medially and was scheduled for revision. No other acetabular component was loose or had been revised. The mean Harris hip score was 81 points (range, 56 to 100 points) at the time of the most recent follow-up. Despite the use of a high hip center, the prevalence of a positive Trendelenburg sign was reduced from 98 percent (forty-five of forty-six hips) preoperatively to 44 percent (sixteen of thirty-six hips) at the time of the most recent follow-up. The short limbs were lengthened a mean of seven millimeters (range, five millimeters of shortening to forty millimeters of lengthening). CONCLUSIONS: In this study of acetabular revisions with use of a high hip center in patients who had major periacetabular bone loss, mechanical failure occurred in 4 percent (two) of the forty-six hips in the entire series and in 6 percent (two) of the thirty-six hips in patients who were alive and still had the implant in place after a mean of 10.4 years of follow-up. The use of a high hip center did not adversely affect function of the abductor muscles, and the mean limb-length discrepancy was reduced by the femoral reconstruction.

Acetabulum↗

PubMed1999

Revision of the acetabular component without cement after a previous acetabular reconstruction with use of a bulk femoral head graft in patients who had congenital dislocation or dysplasia. A follow-up note.

BACKGROUND: Revision of an acetabular component that has failed after a total hip arthroplasty in which a bulk femoral head autogenous graft or allograft was used as a structural graft for acetabular reconstruction is an uncommon but complex and challenging procedure. We previously reported the results for seventy hips at an average of 16.5 years after a total hip arthroplasty in which an acetabular reconstruction had been performed with a femoral head graft. In the present study, we evaluated a subset of nine hips from that series that had a subsequent revision of the acetabular component without cement. The purpose of the current study was to assess the usefulness of the bone graft in this revision. METHODS: The nine patients (nine hips) were followed clinically and radiographically for an average of seventy-six months (range, sixty-one to 114 months) after the index revision. In six hips the autogenous femoral head graft previously had been bolted to the lateral side of the ilium, and in one hip the femoral head allograft had been affixed in this manner. In the two remaining hips, the allograft had been placed within the acetabulum. The hips were classified according to the extent of acetabular bone loss, with use of criteria described previously. Three hips had stage-I bone loss; four, stage-II; and two, stage-IIB. A porous-coated hemispherical acetabular component was inserted without cement and fixed with screws in each hip. At least 70 percent of the porous coating was in contact with viable bone. RESULTS: At the time of the latest follow-up after the index revision, all nine acetabular components were functioning well without loosening or osteolysis and none had been revised. The average Harris hip score was 77 points (range, 61 to 98 points) compared with 49 points (range, 27 to 96 points) preoperatively. One hip had had revision of the femoral stem, and another had had exchange of the acetabular liner because of recurrent dislocations. There was no additional resorption of the residual bulk graft that was in contact with the metal shell in any hip. CONCLUSIONS: In this small series of complex acetabular revisions, the healed bulk graft provided valuable additional bone stock for the support of an acetabular component that was inserted without cement. Insertion of the acetabular component into the available bone, which consisted in major part of host bone and in minor part of united revascularized bulk graft, resulted in a well functioning hip after an intermediate duration of follow-up. In all except two hips, the enlarged bone stock allowed insertion of a larger acetabular component than had been used previously.

Acetabulum↗

PubMed1999

Improving the adverse cardiovascular prognosis of type 2 diabetes.

Approximately 80% of all patients with diabetes die of cardiovascular disease. The traditional management of type 2 diabetes has been ineffective in altering this dismal prognosis. Insulin resistance is the fundamental defect of type 2 diabetes. Insulin resistance often leads to hyperinsulinemia, which is associated with hypertension, atherogenic dyslipidemia, left ventricular hypertrophy, impaired fibrinolysis, visceral obesity, and sedentary lifestyle. Although all these conditions are associated with atherosclerosis and adverse cardiovascular events, the therapeutic efforts in patients with diabetes have focused predominantly on normalizing glucose levels. Improved insulin sensitivity through lifestyle modifications or pharmacologic therapy (troglitazone and metformin) will lower both insulin and glucose levels as well as diminish dyslipidemia and hypertension. In contrast, sulfonylurea agents lower glucose by increasing insulin levels and may increase the risk of cardiovascular events. Therapy including aspirin, lipid agents (for example, statins), angiotensin-converting enzyme inhibitors, beta-adrenergic blockers, postmenopausal estrogen replacement, and vitamin E should be considered for patients with type 2 diabetes. In most patients with diabetes who have multivessel coronary artery disease, coronary artery bypass grafting is superior to coronary angioplasty for improving long-term cardiovascular prognosis. This superiority is mediated in part by the use of a left internal mammary graft to the left anterior descending coronary artery. Urgent coronary angioplasty or thrombolytic therapy should be considered for all patients with diabetes who have acute myocardial infarction.

Antihypertensive Agents↗