The emerging impact of the information age on orthopaedic surgery. Introduction.
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Humans↗
Biomedical subjects
R Poss
Publications and source records attributed to R Poss.
Development of a virtual reality arthroscopic knee simulator.
The virtual reality arthroscopic knee simulator (VR-AKS) consists of a computer platform, a video display, and two force-feedback (haptic) interfaces which also monitor the position of the instruments in the user's hands. The forces that the user would normally apply to the lower limb during arthroscopy are directed through an instrumented surrogate leg. Proprietary software furnishes the mathematical representation of the physical world and replicates the visual, mechanical, and behavioral aspects of the knee while task-oriented programs monitor and record specific areas of user performance. A prototype has demonstrated the feasibility of the system and work on the first, fully functional simulator will begin soon.
Arthroscopy↗
Development of a virtual reality arthroscopic knee simulator.
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Arthroscopy↗
The value and promise of patient databases in orthopaedic surgery.
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Arthroplasty, Replacement↗
Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery.
BACKGROUND: Cardiac complications are important causes of morbidity after noncardiac surgery. The purpose of this prospective cohort study was to develop and validate an index for risk of cardiac complications. METHODS AND RESULTS: We studied 4315 patients aged > or = 50 years undergoing elective major noncardiac procedures in a tertiary-care teaching hospital. The main outcome measures were major cardiac complications. Major cardiac complications occurred in 56 (2%) of 2893 patients assigned to the derivation cohort. Six independent predictors of complications were identified and included in a Revised Cardiac Risk Index: high-risk type of surgery, history of ischemic heart disease, history of congestive heart failure, history of cerebrovascular disease, preoperative treatment with insulin, and preoperative serum creatinine >2.0 mg/dL. Rates of major cardiac complication with 0, 1, 2, or > or = 3 of these factors were 0.5%, 1.3%, 4%, and 9%, respectively, in the derivation cohort and 0.4%, 0.9%, 7%, and 11%, respectively, among 1422 patients in the validation cohort. Receiver operating characteristic curve analysis in the validation cohort indicated that the diagnostic performance of the Revised Cardiac Risk Index was superior to other published risk-prediction indexes. CONCLUSIONS: In stable patients undergoing nonurgent major noncardiac surgery, this index can identify patients at higher risk for complications. This index may be useful for identification of candidates for further risk stratification with noninvasive technologies or other management strategies, as well as low-risk patients in whom additional evaluation is unlikely to be helpful.
Aged↗
Kinematic total knee arthroplasty: a 10- to 14-year prospective follow-up review.
To understand better the type and incidence of long-term complications in total knee replacement, 306 primary Kinematic total knee arthroplasties performed between June 1978 and December 1982 were prospectively reviewed in detail. The Kinematic knee is a nonconstrained, posterior cruciate-retaining prosthesis that has right and left femoral components to afford anatomic tracking of the patella. The overall revision rate was 6.5%. The most common cause for revision surgery was patellar complications. Ten revisions (3.06%) were for patellar component loosening. Two knees were revised for patella subluxation (0.65%); 1 was in a resurfaced rheumatoid patella, and 1 in an unsurfaced osteoarthritic patella. Stair climbing was better with an unsurfaced patella. Anterior knee pain was 21.8% in the unsurfaced patella and 11.2% in the replaced patella. These data suggest patella replacement is not appropriate with this design.
Arthroplasty, Replacement, Knee↗
Preoperative education for total hip and knee replacement patients.
OBJECTIVE: Psychoeducational preparation is known to improve postoperative outcome. We tested two common psychoeducational procedures in elderly orthopedic patients, examining how best to match interventions to patients by psychological type. METHODS: Two hundred twenty-two elderly patients undergoing total hip or knee replacement were randomly assigned to 1) a slide-tape with information on the postoperative, in-hospital rehabilitation experience, or 2) training in Benson's Relaxation Response with a bedside audiotape, in a 2 x 2 factorial design. RESULTS: The relaxation response did not influence postoperative outcomes. The educational intervention reduced length of stay and pain medication use for patients who exhibited most denial (tendency to avoid thinking about unpleasant events), and reduced postoperative anxiety and cognitive errors on the Mini-Mental State Exam for patients with most baseline anxiety. There was no effect on postoperative pain. CONCLUSIONS: The importance of attending to the patient's psychological state and level of preparation before orthopedic surgery is reinforced. Patients who exhibit most denial and highest anxiety may benefit from educational interventions, but patients' directly expressing desire for information may be a poor guide in deciding which patients would benefit, compared with more formal psychological testing for denial and anxiety.
Aged↗
Posterior approach to total hip replacement using enhanced posterior soft tissue repair.
The two senior authors (PMP, RP) independently began using an identical enhanced posterior soft tissue repair after total hip replacement through a posterior approach. In the first author's experience, a dislocation rate of 4% in 395 patients before using the enhanced closure was reduced to 0% in 395 patients in whom the enhanced closure was performed. In the second author's experience, 160 total hip replacements had a dislocation rate of 6.2% before the enhanced closure whereas 124 total hip replacements had a dislocation rate of 0.8% after the enhanced closure. These results are highly statistically significant.
Arthroplasty, Replacement, Hip↗
Body mass index as a correlate of postoperative complications and resource utilization.
PURPOSE: To describe the relationship of body mass index (BMI) with postoperative complications and resource utilization. PATIENTS AND METHODS: Two thousand nine hundred and sixty-four patients 50 years or older undergoing elective noncardiac surgery with an expected length of stay > or = 2 days were enrolled in a prospective cohort study to measure major cardiac complications, noncardiac complications, length of stay, and costs. The setting was an urban teaching hospital. A preoperative history, physical, electrocardiogram (ECG), and chart review were performed by study personnel. Postoperative complications were detected by ECGs, creatine kinase and creatine kinase MB levels, and daily chart review. Total costs were obtained from the hospital's computerized database. RESULTS: Complication rates were not different among BMI groups (underweight < 20, normal 20 to 29, overweight 30 to 34, most overweight > 34), but patients with BMI 30 to 34 and > 34 who underwent abdominal or gynecologic procedures had significantly higher wound infection rates (11% each) than normal weight patients (4.7%) or the underweight (0%). After adjusting for age, race, gender, smoking history, comorbid diseases, procedure type, and insurance status, there were nonsignificant trends toward increased resource utilization by the most overweight patients (BMI > 34). These patients stayed 0.8 days longer (P = 0.13) and had total costs that were $843 higher (P = 0.17) than patients of normal weight (BMI 20 to 29). The underweight patients stayed 0.9 days longer (P = 0.23) and had total costs that were $3,150 higher (P = 0.04) than patients of normal weight. Quadratic models to test for a U-shaped relationship found no correlation between BMI and length of stay, but did find that BMI was significantly correlated with total costs (P = 0.04). This relationship persisted when patients who had complications were excluded from the analysis. CONCLUSIONS: Overall, BMI was not significantly correlated with postoperative complications or length of stay. However, overweight patients who underwent abdominal or gynecologic procedures had higher wound infection rates, and patients with the highest and lowest BMIs had significantly higher adjusted total costs.
Age Distribution↗
Health-related quality of life after elective surgery: measurement of longitudinal changes.
OBJECTIVE: To examine the responsiveness of the 36-Item Short Form Health Survey (SF-36) to clinical changes in three surgical groups and to study how health-related quality of life (HRQL) changes with time among patients who undergo total hip arthroplasty, thoracic surgery for treatment of non-small-cell lung cancer, or abdominal aortic aneurysm (AAA) repair. DESIGN: Prospective cohort study with serial evaluations of HRQL preoperatively and at 1, 6, and 12 months after surgery. SETTING: University tertiary care hospital. PATIENTS: Of 528 patients, more than 50 years of age, who were admitted for these elective procedures, 454 (86%) provided preoperative health status data and are members of the study cohort. At 12 months after surgery, 439 (93%) of the cohort was successfully contacted and 390 (90%) provided follow-up interviews. MEASUREMENTS AND MAIN RESULTS: The Medical Outcomes Study SF-36, the Specific Activity Scale, five validated health transition questions, and a 0 to 100 scale measure of global health were used to assess changes in health status at 1, 6, and 12 months after surgery. Change in health status as measured by the SF-36 demonstrated that physical function and role limitations due to physical health problems were worse 1 month after these three surgeries. However, by 6 months after surgery, most patients experienced significant gains in the majority of the dimensions of health, and these gains were sustained at 12 months after surgery. Longitudinal changes in the SF-36 were positively associated with responses to the five health transition questions, to changes on the Specific Activity Scale and global health rating question, and to clinical parameters for persons who had AAA repair. These findings indicate that the SF-36 has evidence of validity and is responsive to expected changes in HRQL after elective surgery for these procedures. CONCLUSIONS: For the total hip arthroplasty patients, responsiveness was greatest for the SF-36 scales that measure physical constructs. However, for the two other procedures and at various points of recovery, significant changes were observed for all eight subscales, suggesting that responsiveness was dependent on the type of surgery and the timing of follow-up, and that multidimensional measures are needed to fully capture changes in HRQL after surgery.
Aged↗
Complications of total hip arthroplasty associated with the use of an acetabular component with a Hylamer liner.
We observed early failure and radiographic signs of accelerated wear as early as one to three years after insertion, without cement, of a metal-backed acetabular component with a liner made of Hylamer (DePuy). This finding prompted us to review a larger cohort of patients in whom that liner had been used. Two hundred and thirty-three components with a Hylamer liner, evaluated at a minimum of two years, had a mean rate of wear of 0.27 millimeter per year compared with 0.12 millimeter per year for a contemporaneous group of fifty acetabular cups with a conventional ultra-high molecular weight polyethylene liner made by another manufacturer. At a mean of 3.2 years, we found a significant difference (p < 0.000000006) between the mean rate of wear (0.20 millimeter per year) when the Hylamer liner articulated with a DePuy modular cobalt-chromium femoral head and the mean rate (0.29 millimeter per year) when the liner articulated with an Osteonics modular cobalt-chromium femoral head. Radiographic evaluation revealed a significant correlation between the total linear wear and the prevalence of osteolytic lesions (r2 = 0.76, linear regression analysis). We found that wear of 1.5 millimeters or more could be detected by the unaided eye. Because of the positive correlation between osteolysis and wear of 1.5 millimeters or more, we defined a hip with a liner that had that amount of wear as a hip at risk. We concluded that the wear characteristics of a Hylamer liner in vivo are inferior to those of a conventional ultra-high molecular weight polyethylene liner. Also, the rate of wear of the liner is greater when the femoral head is from a manufacturer other than DePuy. A patient who has a total hip replacement that includes a Hylamer liner should be monitored frequently for signs of wear and osteolytic changes. Additional investigations, with longer durations of follow-up and larger populations, are needed to understand fully the importance of our findings.
Adult↗
Early failure of Hylamer acetabular inserts due to eccentric wear.
The authors performed a retrospective review of the survivorship of Hylamer (DePuy Dupont Orthopaedics, Warsaw, IN) acetabular liners following primary arthroplasty of the acetabulum. Between 1990 and 1992, 193 total hip arthroplasties were performed in which Hylamer acetabular liners were implanted. One hundred forty-three of these hips (74%) were available for clinical and radio-graphic follow-up evaluation after a minimum of 2 years. The mean follow-up period was 2.5 years. Five Hylamer liners have been revised for eccentric wear at a mean of 37 months postimplantation and one additional liner is scheduled to be revised at the 34-month follow-up evaluation (total, 4.2% failure rate due to wear). Survivorship of the Hylamer liner, with failure defined as revision due to eccentric wear, was calculated to be 86% (SE, 5.5%) at 4 years. The authors have discontinued the use of Hylamer acetabular liners because of this high early failure rate.
Acetabulum↗
Isolated proximal femoral osteotomy for treatment of residua of congenital dysplasia or idiopathic osteoarthrosis of the hip. Five to ten-year results.
We retrospectively reviewed the five to ten-year results of an isolated proximal femoral osteotomy in two groups of patients. One group consisted of seventeen patients (eighteen hips) who had a residual deformity resulting from congenital dysplasia of the hip; there were fifteen women and two men, and the mean age was thirty-three years (range, twenty-four to fifty-eight years). The other group included sixteen patients (sixteen hips) who had idiopathic osteoarthrosis; there were three women and thirteen men, and the mean age was forty-eight years (range thirty-eight to fifty-seven years). Both groups were evaluated clinically and radiographically, at a mean of 6.1 years (the patients who had residua of congenital dysplasia) and 6.7 years (the patients who had idiopathic osteoarthrosis). Of the seventeen patients who had residual deformity resulting from congenital dysplasia, eight (eight hips) were completely satisfied with the result of the osteotomy at least five years postoperatively; the joint space was improved in five of these patients (five hips) at the latest radiographic evaluation. Nine patients (ten hips) were not satisfied with the result of the osteotomy at the time of the most recent follow-up; four of the (four hips) had a subsequent total hip arthroplasty. Of the sixteen patients who had idiopathic osteoarthrosis, six were completely satisfied with the result of the osteotomy at least five years postoperatively. The joint space was improved in only two patients at the latest radiographic evaluation. The osteotomy did not provide lasting pain relief for seven patients, all of whom had a subsequent total hip arthroplasty. In both diagnostic groups, the most enduring clinical improvement occurred in hips that had the least evidence of osteoarthrotic changes on the preoperative radiographs. In addition, in the group that had residual deformity resulting from congenital dysplasia, the best outcomes were seen in hips with the least degree of acetabular dysplasia.
Adult↗
Osteotomies about the hip for the prevention and treatment of osteoarthrosis.
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Adolescent↗
A safety and efficacy comparison study of two dosing regimens of epoetin alfa in patients undergoing major orthopedic surgery.
Previous studies have demonstrated the efficacy of perioperative Epoetin alfa in decreasing allogeneic transfusion exposure in patients undergoing orthopedic surgery. A randomized, multicenter trial was conducted comparing the safety and efficacy of a weekly Epoetin alfa dosing regimen in patients with hemoglobin levels > or = 10 to < or = 13 g/dL scheduled to undergo major elective orthopedic arthroplasty, with a daily regimen previously shown to be effective. patients on the weekly regimen showed a greater baseline-to-presurgery hemoglobin increase versus the daily regimen group (1.44 +/- 1.029 g/dL versus 0.73 +/- 0.867 g/dL). Moreover, the weekly 600 IU/kg regimen was similar to the daily 300 IU/kg regimen with respect to safety and the avoidance of allogeneic transfusion. These data showed the weekly Epoetin alfa regimen to be at least as efficacious as the daily regimen and more convenient.
Aged↗
Three-dimensional anatomy of the cancellous structures within the proximal femur from computed tomography data.
Quantitative computed tomography was used to investigate the three-dimensional architecture and the density distribution of the cancellous structures of the proximal femur. We examined 10 femora from the cadavera of 10 individuals, 47-83 years old at the time of death. Three anatomic elements could be distinguished: the epiphysis, the epiphyseal scar, and the metaphysis. Although these elements constitute a functional unit, their individual cancellous patterns revealed significant structural differences. The epiphyseal segment had a more reticulate cancellous appearance, whereas the metaphysis demonstrated a more longitudinally oriented trabecular distribution. The three-dimensional reconstruction of the densest epiphyseal trabecular groups showed two different patterns: a dumbbell type (found in eight bones) and a hemispheric type (found in two bones). The epiphyseal scar was a clearly recognizable high-density structure found in all 10 bones. The epiphyseal scar-diaphysis angle was 13-26 degrees higher than the center column-diaphysis angle. The scar appeared as a tray supporting the epiphyseal cancellous structures, supported itself by the metaphyseal intersection of the main compressive and the arcuate trabecular systems. This intersection always occurred in a relatively small band-shaped zone under the central third of the epiphyseal scar. These three discrete anatomical segments within the proximal femur may reflect developmental and functional adaptations determined by joint incongruity or eccentric muscular activity. The present data will serve as a reference for future studies in which the cancellous patterns are used to help with the early diagnosis of states of disease.
Aged↗
The validity and reliability of a Total Hip Arthroplasty Outcome Evaluation Questionnaire.
The Société Internationale de Chirurgie Orthopédique et de Traumatologie (SICOT), the Task Force on Outcome Studies of The American Academy of Orthopaedic Surgeons, and The Hip Society reached a consensus on the nomenclature to be used for the evaluation of the results of total hip arthroplasty. The Task Force of The American Academy of Orthopaedic Surgeons, to assess the results of total hip arthroplasty from the perspective of the patient, subsequently developed a questionnaire that incorporated this nomenclature. The validity and reliability data regarding this questionnaire are reported in this study. Twenty-five patients participated in the reliability test. The non-response rate was five (0.5 per cent) of 941 possible responses. Test-retest reliability was determined by calculating the Spearman correlation coefficients for each question. The coefficients ranged from 0.41 to 1.0 over a mean test-retest interval of sixteen days. Most items had Spearman coefficients that were greater than 0.50, indicating good or excellent reliability. Validity was assessed, for the fifty-four patients who participated, by calculating the Spearman correlation coefficients for the items regarding pain in the affected hip, limitation of usual activities, capacity for walking without support, and the Sickness Impact Profile. The coefficients ranged from 0.11 (pain and limitation of activity) to 0.56 (Sickness Impact Profile and limitation of activity). These coefficients reflected modest associations, as anticipated, indicating that pain, function, and health status are related yet distinct concepts.(ABSTRACT TRUNCATED AT 250 WORDS)
Activities of Daily Living↗