Implant matching has no clinical or scientific basis.
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Cementation↗
Biomedical subjects
R L Barrack
Publications and source records attributed to R L Barrack.
Proprioception following total knee arthroplasty with and without the posterior cruciate ligament.
Proprioception was measured in two groups of patients following successful total knee arthroplasty (TKA). In one group, the posterior cruciate ligament was retained and an unconstrained cruciate-retaining total knee component was used; in the other group, the posterior cruciate ligament was excised and a cruciate-substituting design was implanted. Threshold to detection of passive motion was quantified as a measure of proprioception. The degree of preoperative arthritis was objectively classified according to Resnick and Niwoyama. There was no difference in threshold to detection of passive motion in cruciate-retaining versus cruciate-substituting TKA. In patients with a moderate grade of arthritis before surgery, the postoperative scores were virtually identical. When the grade of preoperative arthritis was severe, patients with cruciate-substituting TKAs performed significantly better than those with cruciate-retaining TKAs.
Aged↗
Demographic biases found in scoring instruments of total hip arthroplasty.
Four hip scoring systems were used in evaluating 200 adult subjects who had no prior history of injury, pathologic condition, or treatment of the hips, knees, lower extremities, or spine. All subjects were in the age range typical of a total hip arthroplasty candidate (average age, 65 years; range, 50-100 years). In addition to a physical examination, complete demographic data were collected on each subject. Data were recorded on standardized flow sheets so that hip scores could be calculated; scores were normalized by dividing the observed scores by the maximum possible score. The average normalized total hip scores were Harris hip score, 90.8%; modified Harris hip score, 91.9%; Merle D'Aubigne score, 93.9%; and Hospital for Special Surgery hip rating 87.5%. Demographic variables that had a significant negative correlation with hip scores included advanced age (particularly past age 85), an income below the poverty level, and the presence of two or more major medical conditions. Differences in hip scores between different study groups that have not been matched for various clinically relevant factors ("case mix") are at least as likely to represent differences in the patient populations as differences in surgical technique or implant design. Hip scores may decline over the course of a 10- to 20-year follow-up period due to the change in a patient's age and/or medical condition rather than any factor relating to the hip arthroplasty.
Age Factors↗
Cost of treating an infected total knee replacement.
Twenty consecutive cases of infected total knee replacements surgically treated between 1990 and 1993 in which complete clinical and financial data were available were reviewed to determine the resources required of the hospital and the surgeon. These results were compared with a similar analysis of a stratified, unselected sample 30 cases each of primary total knee arthroplasty and nonseptic revision total knee arthroplasty during the same period. Parameters compared between the infected total knee replacement, noninfected revision total knee replacement, and primary total knee replacement included number of surgical procedures performed, number of hospitalizations, number of hospital days, total operative time, and total intraoperative blood loss. Financial data included the amount charged and reimbursed by the hospital and by the surgeon. The actual hospital cost was estimated as well. Based on all parameters measured, surgical treatment of the infected total knee implant required 3 to 4 times the resources of the hospital and the surgeon compared with a primary total knee implant and approximately twice the resources of a nonseptic revision total knee implant. The reimbursement received resulted in an estimated net loss of approximately $15,000 per case to the hospital for the group as a whole, but approximately $30,000 per case per Medicare patient.
Aged↗
Drug and alcohol use in orthopedic trauma patients: a prospective study.
Alcohol has been shown to confound the initial assessment of trauma victims, and cocaine is associated with numerous medical and anesthetic complications. A prospective study was performed to determine the prevalence of alcohol and illicit drug use in orthopedic trauma patients at an inner-city teaching hospital. All patients admitted to the orthopedic service during a 2-year period (January 1993 to December 1994) were prospectively studied. Patients < 14 years old were excluded. Blood alcohol levels were determined, and the urine was screened for cocaine, opiates, marijuana, barbiturates, amphetamines, benzodiazepines, and phencyclidine. Demographic data and a medical history were obtained. Seven hundred sixty-six patients met the study parameters. Of these, 628 (82%) had complete drug and alcohol screens available for review. The data were then sorted by diagnosis, mechanism of injury, type of injury (closed versus open), length of inpatient stay, age, sex, and race, and a statistical analysis was performed. The overall incidence of positive drug or alcohol tests was 56%. Twenty-four percent of patients tested positive for two or more drugs, and 9% for three or more. Alcohol (25%) was the most commonly detected drug, followed by cocaine (22%) and marijuana (21%). The highest incidence of drug use was found in males and in those ages 31-40 years. Hospital stay averaged 1.3 days longer in patients with positive screens. Patients with tibia fractures or open fractures, and those injuries sustained by gunshot, altercation, or pedestrian versus motor vehicle accident had the highest incidence of positive screens. These data show that drug-using patients have more severe orthopedic injuries (i.e., open fractures) and require longer hospitalizations. We conclude that drug and alcohol use is widespread in patients presenting with orthopedic injuries and we make recommendations regarding treatment of these patients. The majority of orthopedic trauma resources in this setting is devoted to treating intoxicated patients. Drug and alcohol use is a major social problem and may have an adverse effect on patient care.
Adolescent↗
Concerns with cementless modular acetabular components.
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Acetabulum↗
Economics of the infected total knee replacement.
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Aged↗
Gram stain detection of infection during revision arthroplasty.
We reviewed 194 revision arthroplasties of the hip and knee performed over a ten-year period. The results of intraoperative Gram staining were available in 169 (87%). Thirty-two were found to be infected (11 hips and 21 knees) and 137 had no evidence of infection. Intraoperative Gram staining was negative in all 169 cases. The method therefore had a sensitivity of 0% for detecting infection. We conclude that the absence of organisms on intraoperative Gram staining during revision arthroplasty does not confirm the absence of infection.
Gentian Violet↗
Surgeon work input and risk in primary versus revision total joint arthroplasty.
One hundred twenty stratified nonselected cases of primary and revision total joint arthroplasties performed between 1990 and 1992 in which complete financial and clinical data were available were reviewed. All cases were performed at a single university hospital. Compared with primary total joint arthroplasty, revision surgery involved significantly more operative time, greater blood loss, increased length of stay, and a much higher complication rate. The actual physician reimbursement was not significantly more than for primary procedures. Physician reimbursement constituted 18% of the total fees collected compared with 24% for the actual prosthesis cost. Surgeons performing revision surgery devote significantly more time and are at a higher liability than when performing primary total joint arthroplasty.
Aged↗
Effects of indomethacin on biologic fixation of porous-coated titanium implants.
The effect of perioperative administration of indomethacin on attachment strength and bone growth into porous-coated titanium implants was evaluated in the canine transcortical plug model. Various drug administration protocols simulating clinical use of indomethacin were studied. These included chronic treatment (starting 2 weeks prior to surgery), treatment immediately after surgery, and treatment 3, 6, 9, and 18 weeks following surgery. Indomethacin therapy was continued until sacrifice at 3, 6, 12, 18, or 24 postoperative weeks. Push-out testing was performed to determine the maximum bone-implant interface shear strength, and quantitative histologic analysis was used to determine percentage of bone ingrowth. When indomethacin was administered chronically or immediately after surgery, a statistically significant decrease in bone-implant interface attachment strength was seen at 3 postoperative weeks but not at later periods. No adverse effect was observed in any group after the 3-week period. Quantitative histologic analysis demonstrated no significant differences in percentage bone ingrowth among any of the treatment protocols at 3 or 6 weeks after surgery. No significant difference was observed between any of the groups at 18 or 24 weeks. The results of this study suggest that perioperative administration of indomethacin does not significantly affect attachment strength or bone ingrowth into porous-coated implants except at early periods, in which cases a transient decrease in attachment strength occurs.
Animals↗
The economics of revision arthroplasty.
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Adult↗
Effect of component fixation method on osteolysis in total knee arthroplasty.
Eighty-three total knee arthroplasties done at a single university hospital were reviewed specifically to examine the presence of lysis. Components that were radiographically loose were excluded. The incidence of lysis varied significantly with the method of component fixation. The highest incidence of lysis (30%) was seen when the tibial component was fixed with cement and screws and the femoral component was implanted without cement. When the tibial component was fixed with cement and screws and the femoral components was cemented, the incidence of lysis was 13% (2 of 13). When the femoral component was press fit and the tibia was cemented without screws, the incidence of lysis was 10% (1 of 10). When the femoral and tibial components were cemented and no screws were used, the incidence of lysis was 0 (0 of 12). Using screws with cement to fix the tibial component was associated with a high incidence of lysis and cannot be recommended. A press fit femoral component also may contribute to the incidence of lysis.
Aged↗
Economics of revision total hip arthroplasty.
A study was undertaken to determine the relative work input and risk involved in doing primary total hip arthroplasty compared with revision total hip arthroplasty. These data were compared with the reimbursement to the hospital and to the surgeon. Parameters examined included operative time, length of hospital stay, blood loss, use of bone graft, and incidence of complications requiring further treatment. Revision total hip arthroplasty required significantly more work and risk on the part of the surgeon and significantly more hospital resources. The estimated hospital cost was more than the diagnosis-related group reimbursement for primary cases and dramatically more for revision cases. Actual surgeon reimbursement was less than prosthetic cost and was not significantly higher for revision than primary cases.
Diagnosis-Related Groups↗
The value of contrast arthrography in assessing loosening of symptomatic uncemented total hip components.
Twenty-five patients with symptomatic uncemented total hip components were studied with contrast arthrography prior to surgical exploration. All but one had uncemented femoral stems and 16 had an uncemented acetabular component. As judged by the findings at surgery, on the femoral side the sensitivity, specificity, and accuracy of arthrography were 57%, 60%, and 58% respectively. There was a relatively high incidence of both false positives (17%) and false negatives (25%). On the acetabular side sensitivity, specificity, and accuracy were 29%, 89%, and 62.5%. False negatives were common (31%), while there was only one false positive. The results in this small series show that arthrography has distinct limitations in identifying the fixation status of uncemented total hip components.
Adult↗
Assessment of the symptomatic total hip.
This new information has recently been incorporated into a series of algorithms for evaluating painful cemented and cementless total hip replacements. As the interpretation of many tests varies significantly between cemented and cementless components, the approach to these two situations differs accordingly. Careful review of sequential plain radiographs remains a mainstay of initial evaluation. The sedimentation rate is also a cost effective method of adding useful information. Based on this assessment, cemented and cementless components can be classified as loose, well fixed, or having lysis without being loose. Subsequent evaluation should incorporate new information regarding the effectiveness, limitations, and cost of various diagnostic tests available for the evaluation of the painful total hip replacement.
Bone Cements↗
Wear and corrosion of modular interfaces in total hip replacements.
Modular components allow for the customization of hip replacements to the individual patient. Modular head-neck components allow for mixed material systems to minimize polyethylene wear as well as provide the ability to vary neck length and head size independent of the stem. Modular interfaces, however, result in an increased susceptibility to interface corrosion and wear debris generation. One hundred eight uncemented femoral stems with modular heads retrieved for reasons other than loosening with modular heads were examined for interface corrosion. In addition, in an effort to quantify the amount of wear debris generated at modular interfaces due to cyclic loading, mechanical testing and electrozone particle analysis was used to study various surface, material, and design combinations. Detectable degrees of corrosion were observed in ten of 29 (34.5%) mixed alloy systems and seven of 79 (9%) single alloy components at an average of 25 months in situ. There was no correlation between presence or extent of corrosion or surface damage with time in situ, initial diagnosis, reason for removal, age, or weight. Stems with corrosion were less likely to have bone ingrowth histologically. The results of mechanical testing showed a significant number of wear particles were generated by all head-neck combinations. The wear debris was almost totally in the size range less than 5 microns. As many as 2.5 million particles were generated the first million cycles loading, with as many as eight million particles generated at ten million cycles. The results indicate that surface preparation and material affect particle generation. Head-neck tolerance mismatch appears to be significantly variable in the number of particles generated.
Alloys↗
Surgical treatment of diffuse pigmented villonodular synovitis of the knee.
Twenty-five cases of diffuse pigmented villonodular synovitis of the knee in 23 patients were reviewed to determine the results of surgical treatment. All the cases met strict histologic criteria for diagnosis. Long-term clinical follow-up data (average, 58 months) were available for all patients. One case for a patient who was treated by marginal excision recurred within one year. All other cases (initial and recurrent) were treated by total synovectomy, preserving the functional integrity of the knee. Proximal extensor realignments were performed in patients in which chronic distention had caused a redundancy of retinacular tissues. Adhesions, an early complication in eight patients, responded well to closed manipulation and did not adversely affect long-term functional outcome. The outcome was excellent in seven and good in 16 the patients. Two of the patients have had recurrences but have not had another operation. Using this technique, the recurrence rate (8%) and morbidity are significantly lower than those reported previously.
Adolescent↗
Complications of internal fixation of tibial plateau fractures.
All cases of displaced tibial plateau fractures treated by open reduction and internal fixation at two university hospitals over a 3-year period were retrospectively reviewed. There were 47 fractures in 45 patients. Rigid fixation to allow early motion was the goal in all cases. There were 3 AO type I (wedge) fractures, 20 AO type III (wedge/depression) fractures, and 24 AO type IV (comminuted/bicondylar) fractures. Cases were classified into three groups depending on the amount of hardware used to obtain fixation (a single buttress plate, group 1; a buttress plate and interfragmentary lag screws, group 2; or medial and lateral buttress plates with or without lag screws, group 3). In group 1, there were 20 fractures and no instances of deep-wound infection or postoperative ankylosis. In group 2, infection occurred in 6 of 19 fractures (32%), all of which also developed significant ankylosis including 1 patient who underwent arthrodesis. In group 3, 7 of 8 (87.5%) knees became infected, and the patients experienced other devastating complications, including ankylosis (n = 3), arthrodesis (n = 2), knee disarticulation (n = 1), and above-knee amputation (n = 1). Patients whose knees became infected underwent an average of five subsequent surgical procedures. These results suggest that patients with comminuted tibial plateau fractures requiring either two buttress plates or a single plate with additional interfragmentary lag screws would probably be better managed by either non-operative treatment or limited internal fixation.
Adult↗