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Biomedical subjects

E M Keating

Publications and source records attributed to E M Keating.

At least 19 recordsLinked to original sources
PubMed2001

Does the preoperative radiographic degree of osteoarthritis correlate to results in primary total knee arthroplasty?

The preoperative radiographs of 1,888 patients undergoing 2,759 consecutive total knee arthroplasties (TKAs) performed for osteoarthritis (OA) were retrospectively reviewed to test the hypothesis that patients with less severe OA changes experience less pain relief and lower function scores after TKA. Age at surgery averaged 70.6 years, and follow-up averaged 2.5 years. Preoperatively, pain was independent of an arthritis grade, and this likewise was noted at > or =3 years after surgery. Patients with severe and mild radiographic changes of OA eventually experienced the same degree of function and pain relief after TKA.

Adult↗
PubMed2001

The clinical significance of vacuum mixing bone cement.

This controlled study compared the strength and porosity of 48 polymethylmethacrylate cement-implant constructs prepared with open bowl versus vacuum mix technique. Forty-eight blast finished stainless steel rods of 13 mm diameter were implanted with centralizers into 17-mm inner diameter tubes that had been retrograde filled with polymethylmethacrylate cement. The eight cement preparations used were open bowl and vacuum mixed Simplex, Osteobond, Zimmer Dough Type, or Palacos R. Six replications of each condition were performed. The tubes were maintained at 37 degrees C. Each tube was cut transversely into five segments. The center three segments were used for data analysis: pushout strength, cycles to failure, and interface porosity analysis. Rod pushout data showed there was no significant difference between open bowl and vacuum mixed samples when all cement brands were combined. Mean sheer force for Palacos R vacuum mixed samples was greater than open bowl (634+/-47 versus 423+/-171), whereas the force for the Zimmer Dough Type cement open bowl was greater than that of the vacuum mixed samples (901+/-71 versus 705 +/-82). Cycles to failure data did not show significant differences when open bowl and vacuum mixed samples were compared when cements were analyzed individually or combined. Image analysis of cement-implant interfaces showed that vacuum mixing reduced void area significantly compared with open bowl mixing in the Palacos R and Osteobond preparations. Vacuum mixing does not appear to reduce cement prosthesis interface porosity or improve its mechanical properties in all cements.

Analysis of Variance↗
PubMed2001

Overview: long-term followup: predicting the success of a total knee arthroplasty.

As the number of total knee arthroplasties performed each year in the United States continues to increase, knowledge of long-term prosthetic performance and implant durability is paramount. A selection of the best total knee replacement system for a given patient should be based on long-term followup studies reviewing, among other parameters, survivorship and complications. The importance of such long-term data should not be underestimated.

Arthroplasty, Replacement, Knee↗
PubMed2001

Long-term followup of anatomic graduated components posterior cruciate-retaining total knee replacement.

The purpose of the current study was to evaluate the authors' 15-year experience with the Anatomic Graduated Components total knee replacement. This is a report of the survivorship of 4583 Anatomic Graduated Component total knee arthroplasties. Kaplan-Meier survival analyses were performed with the end point defined as radiographic loosening, revision, or both. This end point was subdivided into the best case scenario in which it was assumed that all the patients lost to followup were doing well throughout the study and a worst case scenario in which it was assumed that all patients lost to followup had failed results at their last clinic visit. There were six (0.18%) femoral, 21 (0.46%) tibial, and 180 (4.2%) all-polyethylene patellar component failures secondary to aseptic loosening. All femoral components and 90% of the tibial components were revised; however, only 15 patellar components were revised. The clinical survival rate with revision of one or more of the components was 98.86% at 15 years. Despite having nearly flat-on-flat geometry and retaining the posterior cruciate ligament, which should increase the stresses in the polyethylene and at the bone-cement interface, this total knee replacement has proved to have minimal wear and excellent longevity with time. The authors think this is a result of the direct compression molded polyethylene articulation and the nonmodular configuration that incorporates metal backing on the tibial component and eliminates back-sided tibial component polyethylene wear.

Adolescent↗
PubMed2001

The failure of all-polyethylene patellar components in total knee replacement.

The patellar component of total knee replacement is the most frequent source of nonseptic complications after total knee arthroplasty. The purpose of the current study was to review the radiographic factors associated with loosening of all-polyethylene patellar components. Four thousand five hundred eighty-three cases of Anatomic Graduated Components total knee replacements were performed at the authors' institution during the past 15 years. Radiographs were reviewed and loosening was defined as global radiolucency or component migration. Four thousand two hundred eighty-seven allpolyethylene patellar components were implanted. There were 180 (4.2%) loose all-polyethylene patellar components. The mean time to loosening was 2.6 years (+/- 1.75 years). Fifteen (0.3%) patellar components required revision. Five radiographic features were associated with failure. The incidence and mean time of appearance were recorded: (number; incidence; time) (1) Bone-cement radiolucency, n = 174, 96.7%, 1.4 years; (2) increased density, n = 118, 65.6%, 1.8 years; (3) trabecular collapse of the bone, n = 160, 88.9%, 2.3 years; (4) patella fracture and fragmentation, n = 133, 73.9%, 2.5 years; and (5) lateral subluxation of the residual patella bone, n = 146, 81.1%, 2.9 years. Lateral retinacular release was associated with an increased rate of patellar loosening. Loosening of the allpolyethylene patella component is an avascular process strongly associated with lateral retinacular release and for which the patient infrequently requires revision surgery.

Adolescent↗
PubMed2000

The effect of intraoperative intravenous fixed-dose heparin during total joint arthroplasty on the incidence of fatal pulmonary emboli.

All patients who underwent primary total knee arthroplasty (TKA), revision TKA, primary total hip arthroplasty (THA), and revision THA between January 1, 1990, and December 31, 1996, were retrospectively reviewed to determine the incidence of fatal pulmonary emboli. All TKA patients received 1,000 U of intravenous heparin sodium before the tourniquet was inflated and an additional 500 U of intravenous heparin sodium before the inflation of the second tourniquet during bilateral TKA. All THA patients received 1,000 U of intravenous heparin sodium at the time of the skin incision and 500 U of intravenous heparin sodium before preparation of the femoral canal. The overall incidence of fatal pulmonary emboli was extremely low (TKA, 0.096%; THA, 0.16%). With this regimen of intravenous intraoperative heparin, postoperative aspirin, thromboembolic disease hose, and early ambulation, there is no risk of postoperative bleeding, it is inexpensive, and there is no concern on how long to keep the patients on this regimen postoperatively. We recommend this regimen for the prevention of fatal pulmonary emboli after total joint arthroplasty.

Aged↗
PubMed2000

Determining the necessity for routine pathologic examinations in uncomplicated total hip and total knee arthroplasties.

Total hip and total knee arthroplasties (n = 951) were retrospectively reviewed to determine the cost-effectiveness of routine pathologic examination of surgical specimens in primary total hip and total knee replacements. Discrepancies between the postoperative diagnosis and the final pathologic diagnoses were recorded. Of the 951 cases reviewed, 27 (2.8%) noted conflicting postoperative and pathologic diagnosis. In all cases, the discrepancy was between a postoperative diagnosis of osteoarthritis and pathologic diagnosis of avascular necrosis. No new cases of neoplasia or inflammatory arthropathy were noted based on the pathologic interpretation. Sixteen of these discrepancies (5.1%) and were noted in total hip arthroplasties, and 11 (1.7%) were noted in total knee arthroplasties. In no case was postoperative medical or surgical treatment altered. Based on this review, strong consideration should be given to the elimination of routine pathologic evaluation of surgical specimens during primary joint arthroplasty, leaving this pathologic evaluation optional, at the discretion of the orthopaedic surgeon, rather than mandatory.

Aged↗
PubMed2000

Windswept deformity in bilateral total knee arthroplasty.

Windswept deformity, when an individual has 1 knee in extreme varus alignment and the other in severe valgus alignment, is an unusual occurrence in patients presenting for bilateral total knee arthroplasty. This condition was evaluated in 22 patients to examine possible differences between knees in the same individual. Differences between the varus and valgus knees included alignment (P = .0001), as expected, and the position of the lateral joint line (P = .0161) preoperatively. No significant differences were observed between these 2 knee categories in any other comparison preoperatively or postoperatively. Total knee arthroplasty in patients with windswept deformity can be expected to be successful in both knees when attention is given to proper alignment and soft tissue balancing intraoperatively.

Aged↗
PubMed2000

Total knee arthroplasty after high tibial osteotomy.

Between 1980 and 1995, 95 consecutive total knee replacements were performed at an average of 10 years 4 months after high tibial osteotomy. The average age of the 82 patients was 66 years, with a preoperative diagnosis of osteoarthritis in 94 knees. One patient died 6 months after surgery. The followup of the remaining 81 patients (94 knees) averaged 8.6 years (range, 2-17 years). Knee Society knee score at final followup improved to an average of 87.6 points from a preoperative average of 38.1 points. No pain was present in 86.2% of knees, and 12.8% of knees had only mild or occasional pain. Tibial radiolucencies were identified in 12 (12.8%) knees at final followup, and in only four knees were radiolucent lines found about the lateral zones. Only one tibial component required revision 3 years after surgery. Although no preoperative factor was identified that predisposed to an inferior knee score, function score, or pain score, the severity of the preoperative flexion contracture and the number of previous surgeries did relate to diminished postoperative motion. However, an increased number of patellar radiolucencies were seen in the knees in which the lateral joint line was raised (referenced from the fibular head) a greater degree. The clinical results of total knee replacement after high tibial osteotomy appeared similar to those of primary total knee replacement. The previous high tibial osteotomy had no adverse effect on the eventual results of a cemented posterior cruciate retaining total knee replacement.

Adult↗
PubMed2000

Is the preoperative radiograph useful in predicting the outcome of a total hip replacement?

The preoperative radiographs of 1015 patients undergoing 1163 total hip replacements for osteoarthritis were evaluated to determine if a relationship exists between the extent of osteoarthritis and the clinical results of a total hip replacement. Preoperative radiographs were graded with respect to the degree of cartilage space loss, direction of cartilage space loss (femoral head migration), and severity of osteophyte formation. Followup averaged 32.1 months (range, 6-93 months). Greater degrees of cartilage space loss correlated with lower hip scores preoperatively but were unrelated to preoperative pain. These patients had statistically less pain at 6 months and 1 year. Patients with superior cartilage space loss before surgery also had statistically less pain at 6 months. However, at 3 years and beyond, pain was independent of degree of preoperative cartilage space loss, osteophyte formation, or femoral head migration. In addition, hip scores at any followup were independent of the degree of osteoarthritis observed on the preoperative radiograph. These findings provide statistical support to the concept that greater degrees of joint space loss correlate with better relief of pain and less severe joint space loss correlates with less relief of pain within the first year after total hip replacement. At 3 years and beyond, hip and pain scores were independent of the degree of preoperative osteoarthritis.

Adult↗
PubMed2000

Total knee arthroplasty after high tibial osteotomy. A comparison study in patients who had bilateral total knee replacement.

BACKGROUND: The outcome of total knee replacement after high tibial osteotomy remains uncertain. We hypothesized that the results of total knee replacement with or without a previous high tibial osteotomy are similar. METHODS: The results of a consecutive series of thirty-nine bilateral total knee arthroplasties performed with cement at an average of 8.7 years after unilateral high tibial osteotomy were reviewed. There were twenty-seven men and twelve women. Preoperatively, the knee scores according to the system of the Knee Society were similar for all of the knees; however, valgus alignment and patella infera were more common in the knees with a previous high tibial osteotomy. Bilateral total knee replacement was staged in seven patients and was simultaneous in thirty-two patients. The results of the total knee arthroplasties were retrospectively reviewed with respect to the knee and function scores according to the system of the Knee Society, the radiographic findings, and the complications. RESULTS: Intraoperatively, no notable differences were identified in the number of medial, lateral, or lateral patellar releases required. However, less lateral tibial bone was resected in the group with a previous high tibial osteotomy (average, 3.3 millimeters) than in the group without a high tibial osteotomy (average, 7.5 millimeters). The average duration of follow-up was 7.5 years (range, three to sixteen years) in the group with a previous high tibial osteotomy and 6.8 years (range, two to ten years) in the group without a high tibial osteotomy. At the time of the final follow-up, the knee and function scores were similar for the two groups (89.0 and 81.0 points, respectively, for the group with a previous high tibial osteotomy, and 89.6 and 83.9 points, respectively, for the group without a high tibial osteotomy). Although more knees were free of pain in the group without a previous high tibial osteotomy (thirty-six) than in the group with a previous osteotomy (thirty-three), this difference was not found to be significant with the numbers available (p = 0.4810). Knee alignment and stability, femoral and tibial component alignment, and range of motion also were similar in both groups postoperatively. One allpolyethylene tibial component was revised in the high tibial osteotomy group. Two knees in each group required manipulation. There were no deep infections. CONCLUSIONS: While patients with a previous high tibial osteotomy may have important differences preoperatively, including valgus alignment, patella infera, and decreased bone stock in the proximal part of the tibia, the present study suggests that the clinical and radiographic results of primary total knee arthroplasty in knees with and without a previous high tibial osteotomy are not substantially different. In our relatively small group of patients, the previous high tibial osteotomy had no adverse effect on the outcome of the subsequent total knee replacement.

Aged↗
PubMed1999

The natural history of a posteriorly dislocated total hip replacement.

A retrospective review was conducted to delineate the natural history of the posteriorly dislocated total hip replacement. A total of 1,036 consecutive total hip replacements were performed between 1989 and 1992. Forty (3.9%) were known to have dislocated posteriorly. Twenty-four of these dislocations occurred after primary replacements, and 16 occurred after revision. Eighty-five percent of the dislocations occurred within 2 months and were reduced closed. No statistical differences were noted between these 2 groups with respect to height, weight, sex, age, and femoral and acetabular anteversion. Nonunion of the greater trochanter, modular femoral neck length, and operative approach appeared to affect hip stability. Twenty-three of the 40 dislocated hips (57.5%) redislocated. Sixteen of the 40 hips (40%) required reoperation for recurrent dislocation. Thirteen of the 16 revisions (81.3%) were successful. A dislocated total hip replacement that has been rendered stable does not preclude one from having a successful total hip replacement, and it does not appear to affect survivorship at intermediate follow-up.

Aged↗
PubMed1999

A comparison of collared and collarless femoral components in primary cemented total hip arthroplasty: a randomized clinical trial.

Between July 1986 and November 1989, 437 consecutive primary cemented total hip arthroplasties were performed using a straight-stemmed titanium alloy femoral component. Collared and collarless versions of this identical stem were randomly chosen by computer allowing a comparison between 213 collared stems (198 patients) and 224 collarless stems (209 patients). Diagnosis, sex, weight, and average age (72.8 years, collared; 72.0 years, collarless) were similar. Follow-up averaged 76 months (collared) and 72 months (collarless) with 49 patients followed for at least 10 years. Calcar-collar contact was noted in 205 hips (96%) on the initial postoperative radiograph. Early complications, including dislocations (5% each group), were similar. Late complications included 3 deep infections (2 collared, 1 collarless) and 2 postoperative femur fractures (1 each). Hip scores at the most recent follow-up averaged 91.2 and 90.1 in the collared and collarless groups. No or slight pain was noted in 93% of collared and 91.5% of collarless hips. Although no radiographic differences were noted in distal cortical hypertrophy, stem subsidence, and osteolysis, collarless hips lost significantly more medial femoral neck cortical bone (average 0.90 mm vs 0.63 mm). A higher incidence of radiolucent lines in femoral zone VI (20.7% vs 9.4%) was also noted in collarless hips.

Aged↗
PubMed1999

Comparison of the midvastus muscle-splitting approach with the median parapatellar approach in total knee arthroplasty.

A total of 100 patients having bilateral total knee replacements simultaneously were randomized prospectively--one knee having a vastus muscle-splitting approach and the other knee having a median parapatellar approach-to evaluate differences in lateral release, postoperative rehabilitation, ease of approach, and complications in total knee replacement surgery. There were 25 lateral releases on the muscle-splitting side and 26 on the median parapatellar side (P = .871). There were no differences in range of motion on day 2 or discharge, straight-leg raise, terminal knee extension, extensor lag, lateral release, or rehabilitation. There were 2 postoperative hematomas and 1 manipulation, all on the muscle-splitting side. All complications occurred from the muscle-splitting side. The muscle-splitting approach cannot be recommended as being superior to the median parapatellar approach.

Adult↗
PubMed1999

Intra-articular morphine and/or bupivacaine after total knee replacement.

The postoperative analgesic effects of intra-articular injections of bupivacaine and/or morphine were examined prospectively in 437 patients who had total knee replacement for osteoarthritis. They were divided randomly into four groups. Group I received 10 mg of morphine (1 ml) and 9 ml of saline, group II received 10 ml of bupivacaine (2.5 mg/ml), group III received 10 ml of saline, and group IV received 10 mg of morphine (1 ml) and 9 ml of bupivacaine (2.5 mg/ml). All analgesics administered in the first 24 hours after operation were recorded. The patients rated their pain on the McGill-Melzack scale at 1, 6, 12 and 24 hours. No significant differences were found between any of the groups in the use of Demoral and/or Toradol in 24 hours, the length of stay in hospital or the pain rating at 1, 6, 12 or 24 hours. Patients in groups I and IV, whose injections included morphine, used significantly more morphine in the first 24 postoperative hours than did groups II or III.

Adult↗
PubMed1999

Radiological factors influencing femoral and acetabular failure in cemented Charnley total hip arthroplasties.

We have made a retrospective review of 185 cemented Charnley total hip arthroplasties performed between 1970 and 1974 to determine the relationships between radiological variables and failure of the femoral and acetabular components. We measured the acetabular wear, the orientation of the cup, the thickness and consistency of acetabular and femoral cement mantles, radiolucency and femoral alignment. The mean follow-up was for 11.7 years. Femoral loosening was demonstrable radiologically in 15 hips (8.1%), ten (5.4%) of which were revised during the period of follow-up. Only when the first postoperative radiograph showed a thin cement mantle in Gruen zone 5 was there a significant association with failure of the femoral component. There were 12 loose acetabular components (6.5%), nine (4.8%) of which were revised. When the initial radiograph after operation showed radiolucency in DeLee and Charnley zone 1, the incidence of acetabular loosening was 28.21%. If such radiolucency was not present, the incidence of acetabular loosening was only 0.69%. Our findings emphasise the importance of careful cementing.

Acetabulum↗
PubMed1999

Assessment of postoperative vigor in patients undergoing elective total joint arthroplasty: a concise patient- and caregiver-based instrument.

Assessment of early postoperative recuperative power (i.e., vigor and functional ability) in surgery patients is considered to be important for optimizing patient rehabilitation, discharge planning, and health system resource utilization. However, no broadly accepted method of patient assessment has been available to measure these parameters. Therefore, a panel of experts was assembled to design an instrument to assess recuperative power in the total joint arthroplasty setting. The instrument consists of both subjective, patient-based, preoperative and postoperative, fixed-ended questions and objective, caregiver-based measures of patient function (i.e., muscle strength and hematocrit [HCT]). The prototype instrument employed the vitality subscale of the Short Form-36 (SF-36), the activities of daily living items from the Western Ontario and McMaster University Osteoarthritis Index (WOMAC-ADL), as well as three novel scales: Well-being, Ready to resume activities, and Ready to leave the hospital. The instrument was tested in 65 patients at two medical centers. The reliability and validity of the three novel psychometric scales were tested by measuring internal consistency and validity by comparison with the standard scales. Postoperative patient Well-being and Ready scales correlated strongly with muscle strength (P < .01), while postoperative HCT correlated with muscle strength (r = 0.4) and Ready scale (P < .01). This analysis suggested that patient well-being and readiness to resume normal activities may be the best surrogates of patient vigor and that these parametric assessments correlate well with functional and laboratory measures of vigor (i.e., muscle strength and HCT). Based on these findings, the final instrument (Version 4.2) consists of a patient questionnaire that can be completed within approximately 5 minutes (12 preoperative and 14 postoperative questions), and a caregiver questionnaire that includes two objective functional tests: muscle strength and HCT. In conclusion, postoperative vigor may be able to be assessed with a concise, patient-based instrument and may provide valuable information for rehabilitation and discharge planning. The utility of this instrument is currently being assessed in a prospective clinical study.

Activities of Daily Living↗