Triad cemented total hip prosthesis.
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Hip Prosthesis↗
Biomedical subjects
E M Keating
Publications and source records attributed to E M Keating.
Prosthetic component failures in hip arthroplasty surgery.
A survey was conducted of the entire membership of the American Association of Hip and Knee Surgeons to determine their experience with total hip arthroplasty (THA) device-related failures. Forty-seven percent of the membership reviewed their preceding 5-year clinical experience and returned the survey instrument. The aggregate 5-year volume encompassed experience with more than 60,000 hip arthroplasties. The median 5-year experience per respondent was 200 metal-based sockets and 214 metal stems. The frequency distribution of the number of hip arthroplasties per respondent was skewed to the right, with fewer surgeons reporting the higher volumes of arthroplasties. In aggregate, 60,115 of the acetabular components used were metal backed. Nonmetal acetabular component usage totaled 3,219. Complete polyethylene failure was defined as fracture or complete wear through of the polyethylene portion of the component. Complete polyethylene failure was seen in 172 metal-backed sockets (29/10,000). Seventy-seven all-polyethylene sockets had complete polyethylene failure (239/10,100). A total of 87 THAs were revised for modular acetabular dissociations for a dissociation rate of 15/10,000. In aggregate, 64,483 metal-stemmed components were used. Femoral stem fractures occurred in 172 for a rate of 27/10,000. A total of 56,965 metallic femoral components were reported as being modular. Dissociation between the femoral head and neck was uncommonly seen (3/10,000). Use of ceramic femoral heads was low (5,023); however, a total of 11 ceramic head fractures were revised in the 5-year period for a failure rate of 22/10,000. The risks of catastrophic prosthetic THA failure are low but vary according to hip component and the manufacturer of the part.
Ceramics↗
Changing transfusion practices in orthopedic surgery.
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Adolescent↗
Survivorship analysis of acetabular revision in medial, lateral, and global primary osteoarthritis.
Acetabular revision rates after cemented total hip arthroplasty vary from series to series in the literature. Little attention has been paid to the type of primary osteoarthritis in these previous series. We studied 782 cemented total hips in 671 patients with an average follow up of 7.5 years. Acetabular revision rates were analyzed in medial, lateral, and global primary osteoarthritis using survivorship analysis. Medial osteoarthritis was associated with a higher acetabular revision rate when compared to lateral osteoarthritis (P = .015). No differences were noted in acetabular revision rates when the preoperative diagnosis was medial vs global or lateral vs global primary osteoarthritis (P = .18 and P = .45, respectively). According to this study, a preoperative diagnosis of medial primary osteoarthritis should be added to a list of several factors associated with increased cemented acetabular failure, especially in the Charnley prosthesis.
Acetabulum↗
Flat-on-flat, nonconstrained, compression molded polyethylene total knee replacement.
Flat-on-flat, posterior cruciate ligament-sparing total knee prostheses recently have shown problems of wear, loosening, and multiple design changes. Two thousand one Anatomical Graduated Components total knee arthroplasties with compression molded, nonmodular polyethylene tibial components were done between 1983 and 1991 at 3 institutions. All knees were evaluated clinically and radiographically every 2 to 3 years; 71 knees were seen in followup > 10 years. There were 8 failures secondary to revision (5 tibial failures; 2 secondary to metalosis from patellar polyethylene dissociation; and 3 femoral failures) resulting in a 98% survival rate at 10 years. The tibial design was flat-on-flat with a compression molded polyethylene that the authors believe is the primary reason for its success.
Adult↗
The effect of heterotopic bone formation on prosthetic loosening after total hip replacement.
Seven hundred thirty-two total hip replacements performed from 1970 to 1980 were evaluated for the degree of heterotopic bone formation postoperatively and its effect on long-term mechanical loosening. There were 231 Charnley total hip replacements, of which 152 had no heterotopic bone formation, 58 had Grade 1 formation, and 21 had Grade 2 or 3 formation. Among the 123 Mueller total hip replacements, 98 had no heterotopic bone formation, 19 had Grade 1 formation, and 6 had Grade 2 or 3 formation. For the 378 T-28 total hip replacements, there were 305 with no heterotopic bone formation, 59 with Grade 1 formation, and 14 with Grade 2 or 3 formation. Survival analyses using the definition of failure as loosening, fracture, or revision of the acetabulum or femoral components were constructed. There was no correlation between mechanical loosening, fracture, or revision of the total hip replacement and any degree of heterotopic bone formation.
Arthritis, Rheumatoid↗
Comparison of polyethylene wear in machined versus molded polyethylene.
Polyethylene wear debris has been identified as a cause of osteolysis, granuloma formation, and loosening in total hip arthroplasty. This study was designed to evaluate differences in polyethylene wear rates between acetabular cups machined from extruded bar stock and those direct compression molded. Two hundred thirty-six hip prostheses underwent radiographic evaluation using the technique of Livermore et al. Seventy-four were all-polyethylene cups machined from extruded bar stock, and 162 were all-polyethylene cups direct compression molded. Both groups were similar in that the acetabular and femoral components were all cemented, the acetabular components were all polyethylene, nonmetal backed, and bearing surfaces of both groups were polished, cobalt chrome. The femoral components were TRIAD in the machined group and TR28 in the molded group. Patient matching was performed, assigning 54 patients in each group, whose average age was 66 years old, average followup 6.7 years, and average weight 161 pounds. Rates of polyethylene wear then were compared. Results showed a linear wear rate of 0.05 mm per year for compression-molded polyethylene and 0.11 mm per year for machined polyethylene. Results of this study raise questions regarding the types of polyethylene fabrication and its ultimate molecular weight, and wear resistance.
Acetabulum↗
Polyethylene wear in total hip arthroplasty.
Polyethylene wear increasingly has been blamed for osteolysis and granuloma formation after total joint arthroplasty. The authors evaluated the wear difference between bearing surfaces of stainless steel, cobalt chrome, and titanium alloy. They also compared cemented all-polyethylene molded cups with cemented metal-backed molded acetabular cups. These were compared with molded and machined polyethylene cups. Two patient groups were matched individually for gender, age, weight, and length of followup. Analyses were done using the technique of Livermore et al. The bearing surface evaluation consisted of 3 groups after matching, leaving 77 patients per group. Results showed linear wear rates of 0.06 mm per year, 0.05 mm per year, and 0.08 mm per year for stainless steel, cobalt chrome, and titanium alloy, respectively. The comparison between cemented molded metal-backed and nonmetal-backed acetabular components was not matched, with 134 metal-backed and 99 nonmetal-backed components. Results showed linear wear rates of 0.011 mm per year in the metal-backed group and 0.08 mm per year in the nonmetal-backed group. Results were statistically significant. These results indicate that the metal composition of the femoral bearing surface has minimal, if any, effect on the linear polyethylene wear rate. The method of polyethylene fabrication and the use of metal backing had a significant effect on the polyethylene wear rate in these patient groups. These results suggest that the compression-molded all-polyethylene acetabular component may be optimal for reducing polyethylene wear in total hip arthroplasty.
Aged↗
Long-term outcomes of contralateral knees after unilateral total knee arthroplasty for osteoarthritis.
One hundred fifty-six patients who underwent unilateral total knee arthroplasty (TKA) between 1970 and 1985 were evaluated for the development, progression, and eventual TKA in the contralateral knee. At the time of TKA, 113 patients were diagnosed with osteoarthritis in the opposite knee, while in the remaining patients, the opposite knee was normal. The probability of the normal knee developing osteoarthritis and requiring a TKA at 7 years is 21 and 5%, respectively. The chance of a knee diagnosed as osteoarthritic at the time of surgery needing a TKA at 10 years is 37%.
Aged↗
Clinical and radiographic evaluation of long-stem femoral components following revision total hip arthroplasty.
Fifty-four consecutive, long-stem revision hip arthroplasties were performed in 53 patients. In order to evaluate periprosthetic femoral changes, all cases utilizing cement, requiring bone-grafts for prosthetic stability, or with a follow-up period of less than 2 years were omitted. Thus, 32 long-stem revision hip arthroplasties in 32 patients were reviewed. Twenty-three Porous Coated Anatomic (Howmedica, Rutherford, NJ) and nine Bi-Metric (Biomet, Warsaw, IN) stems were implanted, with an average follow-up period of 3.6 years (range, 2-6 years). Prosthetic canal fill averaged 94% proximally and 80% distally. Intraoperative complications included three femoral shaft fractures. Harris hip scores averaged 47.8 points, before surgery and 87.6 points at the final follow-up evaluation, with 81% of patients the pain-free. Only three cases of subsidence and one case of osteolysis were noted. By 1 year, proximal osteopenia (off-load) (P = .005), bony condensation about the porous surface (spot weld) (P = .01), and pedestal formation (P = .004) were observed. The presence of distal cortical hypertrophy, (P = .02) spot weld (P = .001), and pedestal formation (P = .05) correlated significantly with off-load. Pedestal formation and distal cortical hypertrophy were commonly found together (P = .001). Despite significant periprosthetic remodeling, adequate fixation and satisfactory early clinical scores were achieved in this setting. Contrary to similar reviews using extensive bone-grafts, acceptable pain-free clinical results were obtained with these components.
Female↗
Measurement of polyethylene thickness in total hip arthroplasty. A technique analysis.
Accurate radiographic measurement techniques are necessary to evaluate wear characteristics of different metals, ceramics, and plastics. This study evaluated a standard technique for radiographic measurement of acetabular component thickness. Twenty-one acetabular components retrieved after revision surgery were studied. Radiographic measurement of polyethylene thickness was performed at two points on radiographs taken within 2 months of the revision surgery. Measurements were made at the area of greatest polyethylene wear and at the center of the component, and these measurements were compared to direct measurement of the retrieved component. The 42 data points obtained revealed an average difference between the radiographic and direct measurements of 0.18 mm. A regression model demonstrated no significant difference (P = .85) between these measurements. Additionally, when comparing the central-point measurement to the thinnest wear-point measurement, no difference was noted, indicating that wear in the sagittal plane did not affect radiographic measurement accuracy. Radiographic measurement of acetabular component thickness is accurate to within 0.18 mm. This degree of accuracy allows for radiographic wear analysis, as long as the standard measurement technique is utilized.
Hip Prosthesis↗
Closed wound drainage in total hip or total knee replacement. A prospective, randomized study.
We prospectively randomized 415 total joint replacements for either a closed wound-drainage system or no postoperative drainage. Drainage was not used in 200 total joint replacements, of which 138 were total knee replacements and sixty-two, total hip replacements. Drainage was used in 215 total joint replacements, of which 137 were total knee replacements and seventy-eight, total hip replacements. All patients were evaluated for the presence of excessive postoperative drainage that necessitated cessation of the range-of-motion exercises, the amount of transfused blood (homologous and autologous), and the preoperative and postoperative hemoglobin levels. The range of motion was assessed daily in the patients who had a total knee replacement. No statistical difference was found in the number of patients who had excessive postoperative drainage from a drained or non-drained wound. There was also no statistical difference with respect to the amount of transfused blood and the preoperative and postoperative hemoglobin levels. Furthermore, in the patients who had a total knee replacement, there were no statistical differences between drained and non-drained wounds with respect to the daily range of motion during the first seven days postoperatively. The mean amount of blood transfused was 157 milliliters in the total knee replacements with drains, 160 milliliters in the total knee replacements without drains, 188 milliliters in the total hip replacements with drains, and ninety-three milliliters in the total hip replacements without drains.(ABSTRACT TRUNCATED AT 250 WORDS)
Blood Transfusion↗
Radiolucency at the bone-cement interface in total knee replacement. The effects of bone-surface preparation and cement technique.
Three hundred and sixty-three knees (221 patients) that had been treated with total arthroplasty between 1975 and 1985 were divided into three groups on the basis of the preparation of the surface of the bone and the technique of the cement application. Group 1 (155 knees) was treated with irrigation of the bone surfaces with a syringe and manual packing of the bone cement. Group 2 (sixty-one knees) had high-volume, high-pressure lavage of the bone surfaces and manual packing of the cement. Group 3 (147 knees) had high-volume, high-pressure lavage and pressure injection of low-viscosity methylmethacrylate cement. Radiolucency was evaluated at each follow-up interval, and the findings were subjected to chi-square analysis and Kaplan-Meier survival analysis. Chi-square analysis of the data at one and three years indicated a significantly higher frequency of lines at the bone-cement interface in the femur and tibia in Group-1 knees compared with those in Groups 2 and 3. The survival curves showed increasing rates of radiolucency adjacent to the tibial components of the knees that had been prepared with lavage that was not high-volume and high-pressure and that had been prepared with finger-packing of cement (Group 1). This may partially explain the clinical problem of loosening of tibial components despite acceptable alignment. This study demonstrates that proper preparation of the cancellous bone and pressurization of the cement reduce the initial occurrence of a radiolucent line, which may have a positive effect on the ultimate failure of at least the tibial component.
Aged↗
A new radiographic evaluation of primary osteoarthritis.
Two thousand five hip radiographs, both AP and lateral, were evaluated for osteoarthritis. We excluded all cases of traumatic osteoarthritis, rheumatoid arthritis, avascular necrosis, and congenital deformities. This left 1578 hips in 1309 patients, which were sub-divided into three categories: medial osteoarthritis (405 hips, 20% of which were bilateral, 68% women, 32% men); superior lateral osteoarthritis (934 hips, 19% of which were bilateral, 49% men, 51% women); and global osteoarthritis (239 hips, 23% bilateral, 53% men, 47% women). These categories may have significance in operative technique and survival of acetabular cups after total hip arthroplasty.
Adult↗
Symposium: options in transfusion therapy.
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Adult↗
Long-term survival analysis of a posterior cruciate-retaining total condylar total knee arthroplasty.
From 1975 to 1983, 278 patients received 418 posterior cruciate ligament-retaining Total Condylar knee arthroplasties. Twenty-four patients were excluded, 15 for lack of followup data, 6 for infection during followup, and 3 for revision surgeries for previous infections. The 394 remaining knees were observed from 1 to 18 years (mean, 8.08 years). Kaplan-Meier and crude survival estimates at 12 years were 96.8% and 98.1%, respectively. Various survival analyses by other authors have yielded similar successful results.
Adult↗
Polyethylene wear in uncemented acetabular components.
We measured polyethylene wear in 231 porous-coated uncemented acetabular cups. We divided the hips into two groups according to the fixation of the femoral component, by cementing (n = 97) or press-fit (n = 134). Follow-up was from three to five years. The patients in two sub-groups were matched for weight, diagnosis, sex, age and length of follow-up. The linear wear rate of cups articulated with uncemented femoral components (0.22 mm/year) was significantly higher than the wear rate (0.15 mm/year) of cups articulated within cemented femoral components (p < 0.05). These results can be compared with previously reported wear rates of 0.08 mm/year for cemented all-polyethylene cups and 0.11 mm/year for cemented metal-backed cups. The higher wear rates of uncemented arthroplasties could jeopardize the long-term results of this type of hip replacement.
Acetabulum↗
Postoperative alignment of total knee replacement. Its effect on survival.
Four hundred twenty-one posterior cruciate condylar total knee arthroplasties were performed between 1975 and 1983. Anatomic alignment of the knee was recorded on follow-up evaluations from two months to 13 years postoperatively. Patients were stratified into a normal group that was 5 degrees to 8 degrees anatomic valgus, a varus group that was from 4 degrees anatomic valgus to any degree of varus, and a valgus group that was more than 9 degrees anatomic valgus. There were eight failures, five in the varus group and three in the normal group. There were no failures in the valgus group. Kaplan-Meier survival curves showed no significant difference between normal and valgus groups; however, there was a statistical difference between the valgus and varus and the normal and varus groups. A surgeon should align a total knee prosthesis in neutral or a slight amount of anatomic valgus to give the patient the best chance for long-term survival.
Aged↗