Biomedical subjects

S B Haas

Publications and source records attributed to S B Haas.

At least 19 recordsLinked to original sources

PubMed2000

Meta-analysis of thromboembolic prophylaxis after total knee arthroplasty.

We performed a meta-analysis of the English literature to assess the efficacy of four common regimes for thromboembolic prophylaxis after total knee arthroplasty: aspirin, warfarin, low-molecular-weight heparin (LMWH) and pneumatic compression. We reviewed 136 articles and abstracts published between January 1980 and December 1997. Papers not using routine venography and a lung scan or angiography to detect deep-venous thrombosis (DVT) and pulmonary emboli (PE) respectively, were excluded. Of the 136 studies, 23 with 6,001 patients were selected. The incidence of DVT was 53% (1,701/3,214) in the aspirin group, 45% (541/1,203) in the warfarin group, 29% (311/1,075) in the LMWH group, and 17% (86/509) in the pneumatic compression device group. Intermittent pneumatic compression devices and LMWH were significantly better than warfarin (p < 0.0001) or aspirin (p < 0.0001) in preventing DVT. The incidence of asymptomatic PE was 11.7% in the aspirin group (222/1,901), 8.2% (101/1,229) in the warfarin group and 6.3% (24/378) in the pneumatic compression group. No studies with LMWH used routine lung scans. Warfarin and pneumatic compression were significantly better than aspirin in preventing asymptomatic PE (p < 0.05). The incidence of symptomatic PE was 1.3% (23/1,800) in the aspirin group, 0.4% (2/559) in the warfarin group, 0.5% (2/416) in the LMWH group and 0% (0/177) in the pneumatic compression group. No statistically significant difference was noted between the above prophylactic regimes due to the very small incidence of symptomatic PE. Prophylaxis for thromboembolic disease in TKA may have to include a combination of some of the above regimes to incorporate their advantages.

Anticoagulants↗

PubMed1998

Patella height after high tibial osteotomy with internal fixation and early motion.

The purpose of this study was to compare the incidence of patella infera in patients after high tibial osteotomy treated with either postoperative immobilization or internal fixation and early range of motion. A retrospective review of 98 patients with high tibial osteotomy was done at the authors' institution. Thirty-three patients who had secondary procedures such as concomitant ligamentous reconstruction with early motion were excluded. Therefore, 69 knees in 65 patients remained in the study cohort. Group A consisted of 32 patients (34 knees) treated with postoperative immobilization, whereas Group B included 33 patients (35 knees) treated with internal fixation and early motion. The preoperative and postoperative Insall-Salvati index, Blackburne-Peel index, and angular alignment were determined for each group. Between Groups A and B, the differences in the Insall-Salvati index and the Blackburne-Peel index were statistically significant, although the difference in angular correction was not significant. With rigid fixation and early motion the Insall-Salvati index showed that there was less postoperative shortening of the patellar tendon. The relationship of the patella to the remainder of the knee was affected less adversely as evidenced by the Blackburne-Peel index. High tibial osteotomy with internal fixation and early range of motion should result in a better knee and ease the subsequent performance of a total knee arthroplasty.

Arthroplasty, Replacement, Knee↗

PubMed1998

Ultrasound screening for deep venous thrombosis after total knee arthroplasty. 2-year reassessment.

The efficacy of ultrasound compared with ascending venography for the detection of deep venous thrombosis immediately after total knee arthroplasty was assessed after a 2-year interval. One hundred thirty-seven patients were eligible for the study; however, 31 patients received only one of the screening methods and a color Doppler examination was inconclusive in six patients. Therefore, 100 patients had a Doppler examination and a venogram. Overall, the sensitivity of ultrasound was 85%, the specificity 97%, the positive predictive value 85%, the negative predictive value 97%, and the accuracy 95%. The sensitivity in the calf was 83%, in the popliteal vein 86%, and in the femoral vein 100%. Two years ago, the initial assessment of ultrasound for the detection of deep venous thrombosis after surgery in patients who had total joint arthroplasty revealed a 75% sensitivity, 99% specificity, 91% positive predictive value, 97% negative predictive value, and 97% accuracy. The sensitivity in the calf was 83%; the sensitivity in the popliteal vein was 40%; and the sensitivity in the femoral vein was 50%. After 2 years of using this screening test with one technician and one radiologist, an improvement with this noninvasive technique was shown. However, it was found that Doppler imaging is not as sensitive as venography for detecting calf thrombi. Any imaging technique should be validated by each institution to determine the validity of the instrument and the learning curve of the technician administering the examination.

Adult↗

PubMed1998

Venous haemodynamics after total knee arthroplasty: evaluation of active dorsal to plantar flexion and several mechanical compression devices.

We performed a crossover study to evaluate the haemodynamic effect of active dorsal to plantar flexion and seven pneumatic compression devices in ten patients who had a total knee arthroplasty. Using the Acuson 128XP/10 duplex ultrasound unit with a 5MHz linear array probe, we assessed the augmentation of peak venous velocity and venous volume above and below the junction of the greater saphenous and common femoral veins in order to study both the deep and superficial venous systems. The pneumatic compression devices evaluated included two foot pumps (A-V Impulse System and PlexiPulse Foot), a foot-calf pump (PlexiPulse Foot-Calf), a calf pump (VenaFlow System) and three calf-thigh pumps (SCD System, Flowtron DVT and Jobst Athrombic Pump). The devices differed in a number of ways, including the length and location of the sleeve and bladder, the frequency and duration of activation, the rate of pressure rise, and the maximum pressure achieved. A randomisation table was used to determine the order of the test conditions for each patient. The enhancement of peak venous velocity occurred primarily in the deep venous system below the level of the saphenofemoral junction. The increases in peak venous velocity were as follows: active dorsal to plantar flexion 175%; foot pumps, A-V Impulse System 29% and PlexiPulse 65%; foot-calf pump, PlexiPulse, 221%; calf pump, VenaFlow, 302% and calf-thigh pumps, Flowtron DVT 87%, SCD System 116% and Jobst Athrombic Pump 263%. All the devices augmented venous volume, the greatest effect being seen with those incorporating calf compression. The increases in ml/min were found in the deep venous system as follows: foot pumps, A-V Impulse System 9.6 and PlexiPulse Foot 16.7; foot-calf pump, PlexiPulse, 38.1; calf pump, VenaFlow, 26.2; calf-thigh pumps, Flowtron DVT 61.5, SCD System 34.7 and Jobst Athrombic Pump 82.3. Active dorsal to plantar flexion generated 8.5 ml for a single calf contraction.

Aged↗

PubMed1998

Magnetic resonance imaging of articular cartilage in the knee. An evaluation with use of fast-spin-echo imaging.

The purpose of this study was to demonstrate that specialized magnetic resonance imaging provides an accurate assessment of lesions of the articular cartilage of the knee. Arthroscopy was used as the comparative standard. Eighty-eight patients who had an average age of thirty-eight years were evaluated with magnetic resonance imaging and subsequent arthroscopy because of a suspected meniscal or ligamentous injury. The magnetic resonance imaging was performed with a specialized sequence in the sagittal, coronal, and axial planes. Seven articular surfaces (the patellar facets, the trochlea, the femoral condyles, and the tibial plateaus) were graded prospectively on the magnetic resonance images by two independent readers with use of the 5-point classification system of Outerbridge, which was also used at arthroscopy. Six hundred and sixteen articular surfaces were assessed, and 248 lesions were identified at arthroscopy. Eighty-two surfaces had chondral softening; seventy-five, mild ulceration; fifty-three, deep ulceration, fibrillation, or a flap without exposure of subchondral bone; and thirty-eight, full-thickness wear. To simplify the statistical analysis, grades 0 and 1 were regarded as disease-negative status and grades 2, 3, and 4 were regarded as disease-positive status. When the grades that had been assigned by reader 1 were used for the analysis, magnetic resonance imaging had a sensitivity of 87 per cent (144 of 166), a specificity of 94 per cent (424 of 450), an accuracy of 92 per cent (568 of 616), a positive predictive value of 85 per cent (144 of 170), and a negative predictive value of 95 per cent (424 of 446) for the detection of a chondral lesion. Interobserver variability was minimum, as indicated by a weighted kappa statistic of 0.93 (almost perfect agreement). With use of this readily available modified magnetic resonance imaging sequence, it is possible to assess all articular surfaces of the knee accurately and thereby identify lesions that are amenable to arthroscopic treatment.

Adult↗

PubMed1998

Primary total knee arthroplasty in stiff and ankylosed knees.

This study reviewed 71 patients who underwent 82 total knee arthroplasties between 1974 and 1987. All patients had severe limitations of motion preoperatively with a total preoperative arc of motion of < or = 50 degrees. Follow-up ranged from 2 to 12 years (average: 5.3 years). The average preoperative knee score was 38 (range: 14 to 54). The average preoperative arc of motion was 36 degrees (range: 0 degree to 50 degrees), with an average flexion contracture of 22 degrees average maximum flexion of 58 degrees. Postoperatively, the average knee score was 80 (range: 0 to 98). The average postoperative arc of motion was 93 degrees (range: 35 degrees to 130 degrees), with an average maximum flexion of 94 degrees. Nine knees had 5 degrees flexion contractures, while 5 knees had 10 degrees flexion contractures. Postoperatively, no knee had a flexion contracture > 10 degrees. Two knees had a decreased range of motion postoperatively. Two knees with severe flexion-valgus deformities developed peroneal nerve palsies that both resolved. Total knee arthroplasty in stiff or ankylosed knees can produce good or excellent results and can lead to significant improvement in range of motion and pain.

Arthritis, Rheumatoid↗

PubMed1997

Comparison of extradural and general anaesthesia on the fibrinolytic response to total knee arthroplasty.

Extradural anaesthesia is associated with lower incidences of deep vein thrombosis after total knee arthroplasty. It is not known if the type of anaesthesia influences thrombogenesis or fibrinolysis during knee surgery performed under tourniquet. We studied 31 patients allocated randomly to receive either extradural or general anaesthesia for primary unilateral total knee arthroplasty performed under tourniquet. Radial artery blood samples were obtained before surgery, during surgery with the tourniquet inflated and on deflation of the tourniquet. Plasma samples were assayed for markers of thrombin generation and fibrinolysis. Two of the circulating indices of thrombin generation, fibrinopeptide A and thrombin-antithrombin complexes, increased to a similar degree in the perioperative period in both groups. Fibrinolytic activity was similar in both groups, as measured by tissue plasminogen activator (t-PA) antigen, t-PA activity, t-PA-plasminogen activator inhibitor complexes, alpha 2-plasmin inhibitor-plasmin complexes and D-dimer. Extradural and general anaesthesia did not result in significant differences in either thrombin generation or fibrinolytic activity during total knee arthroplasty performed under tourniquet.

Aged↗

PubMed1996

Knee closure in total knee replacement: a randomized prospective trial.

A randomized prospective study of 75 total knee replacements in 64 patients who were randomized to capsular closure with the knee in full extension or in flexion was done. Thirty-one knees received a posterior cruciate ligament retaining prosthesis and 44 knees received a posterior stabilized prosthesis. Preoperatively, there was no significant difference between the groups, and patients were stratified by surgeon and type of prosthesis. Postoperatively, all patients were evaluated by a physical therapist who did not know the type of prosthesis the patient received. In addition to the range of motion obtained at discharge; the number of days required to achieve unassisted transfer; the number of days required to achieve assisted and unassisted use of a walker, cane, and stairs; and the number of days to discharge from the hospital were recorded. All patients were also evaluated at 2 to 3 months postoperatively, and the Knee Society clinical rating system scores were compared. There was no statistically significant difference in any of the early rehabilitation parameters or in the 2- to 3-month followup data. Moreover, there was no statistically significant difference in the rate of complications. With stratification according to the type of prosthesis used or the surgeon performing the operation, there was still no statistically significant difference in any of the studied parameters. It was therefore concluded that the degree of knee flexion at the time of capsular closure in total knee replacement has no effect on early rehabilitation after total knee replacement.

Activities of Daily Living↗

PubMed1996

Randomized trial of epidural versus general anesthesia: outcomes after primary total knee replacement.

To compare the effects of epidural anesthesia and general anesthesia on early postoperative outcomes after unilateral primary total knee replacement, 262 patients were randomly assigned to receive either epidural or general anesthesia. All patients received a common rehabilitation protocol including a standardized assessment of progress. One hundred eighty-eight patients received a common thromboembolic prophylaxis protocol with postoperative aspirin, and had a standardized surveillance protocol to detect thromboembolic complications. Deep vein thrombosis was determined by venography on the operative limb, and pulmonary embolism was determined by comparison of preoperative and postoperative lung perfusion scans. The epidural anesthesia group reached all rehabilitative milestones earlier postoperatively than did the general anesthesia group, with a statistically significant earlier attainment of stair climbing. The incidence of deep vein thrombosis was 40% with epidural anesthesia, and 48% with general anesthesia. There were no clots proximal to the popliteal veins. The incidence of pulmonary embolism on lung scan was 12% with epidural anesthesia and 9% with general anesthesia. Epidural anesthesia is associated with more rapid achievement of postoperative in hospital rehabilitation goals after total knee replacement. A minor reduction in postoperative deep vein thrombosis rate was observed with epidural anesthesia, but this did not reach statistical significance. No difference in early postoperative pulmonary embolism was observed between the 2 types of anesthesia.

Aged↗

PubMed1996

Revision total knee arthroplasty due to aseptic failure.

Revision TKA for aseptic failure presents the surgeon with a variety of technical problems. The major problems include loss of bone stock and inadequacy of soft-tissue constraints. Historically, these patients have done poorly but when these problems are adequately addressed with the appropriate surgical technique and appropriate choice of implant, then the results are quite good.

Humans↗

PubMed1996

Occupational knee injuries.

This article focuses on occupational knee injuries. After an overview of work-related injuries, sections on the following are presented: (1) occupational knee injuries (patient history, physical examination, laboratory tests, radiographic tests, and treatment); (2) patellar and quadriceps tendinitis; (3) occupational osteoarthritis (overview and treatment); and failed knee surgery.

Humans↗

PubMed1995

Resection specimen analysis of proximal tibial anatomy based on 100 total knee arthroplasty specimens.

Although it is known that there is some asymmetry of the tibial plateau, most total knee arthroplasty designs currently have a symmetric tibial component. Using resection specimen analysis of the tibial plateau from 100 total knee arthroplasty specimens, the authors have examined the tibial plateau to further delineate, quantitatively, the medial and lateral tibial configuration. Unmagnified radiographs of each of the specimens were produced. A line was drawn along the mediolateral axis. The midpoint and points 10, 20, and 30% from the medial and lateral peripheries were then calculated. The average anteroposterior medial 10, 20, and 30% dimensions were 3.79, 4.74, and 5.06 cm, respectively. The average anteroposterior lateral 10, 20, and 30% dimensions were 3.48, 4.10, and 4.16 cm, respectively. The ratios of the lateral/medial anteroposterior distances at 10, 20, and 30% from the periphery were 92.10, 86.77, and 82.46%, respectively. A total knee arthroplasty system that recognizes the difference in the medial and lateral tibial plateaus and designs a prosthesis to account for the smaller, lateral tibial plateau may achieve the goal of maximizing tibial coverage as well as eliminate the problems associated with a symmetric design.

Arthritis, Rheumatoid↗

PubMed1995

Hip arthroplasty in patients with chronic renal failure.

Patients with chronic renal failure who underwent total hip arthroplasty were retrospectively evaluated. Thirty hips in patients with renal transplants and 16 hips in patients on chronic renal dialysis were reviewed. The average follow-up period was 54 months. The renal transplant patients exhibited generally satisfactory results. Their postoperative course was comparable to that of patients with avascular necrosis undergoing hip reconstruction without underlying renal disease. However, patients undergoing hip arthroplasty while on chronic renal dialysis had poor results (81%), including a deep infection rate of 19%. It was concluded that total hip arthroplasty be reserved for patients who are expecting a renal transplant or preferably those who have already received a successful transplant.

Adult↗

PubMed1995

Primary total knee arthroplasty after patellectomy.

The results of twenty-two consecutive primary total knee replacements, performed an average of nine years (range, one to twenty-three years) after a patellectomy in twenty-two patients, were reviewed retrospectively. The average duration of follow-up was seven years (range, three to fifteen years). The average age of the patients at the time of the arthroplasty was sixty-seven years (range, thirty-six to eighty-nine years). The average Hospital for Special Surgery knee score was 46 points (range, 22 to 74 points) preoperatively and 76 points (range, 45 to 97 points) postoperatively. Thirteen patients had an excellent or good result and seven had a fair or poor result; in two patients, the operation was considered a failure. Except for one patient who had myasthenia gravis, all patients could climb stairs in reciprocal manner. Four patients lacked 5 to 20 degrees of active extension compared with passive extension. With respect to the over-all results, there was no significant difference among the four types of prostheses that were used (p = 0.2). The patients who had received an Insall-Burstein posterior stabilized prosthesis had better scores for pain and function than did the patients who had received a total condylar I prosthesis (p = 0.005 and 0.01, respectively). There was a direct correlation between the knee score and the number of years that had elapsed since the patellectomy. The longer the interval between the patellectomy and the total knee replacement, the higher the postoperative knee score (r = 0.78, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1995

Revision total knee arthroplasty with use of modular components with stems inserted without cement.

We reviewed the results of seventy-six revision total knee replacements, performed between 1980 and 1988 on the Knee Service at The Hospital for Special Surgery, in seventy-four patients. Sixty-five patients (sixty-seven knees; 88 percent) had a complete clinical examination and radiographic evaluation, and nine patients (nine knees; 12 percent) were only interviewed by telephone. Survivorship analysis was performed for all patients. The average duration of follow-up was three years and six months (range, two to nine years). Only patients who had had revision of the femoral component or the tibial component, or both, because of aseptic failure were included. The tibial component of all prostheses that were used for revision had a metal backing. Cement was placed on the cut surfaces in the metaphyseal region of the femur and tibia. Fluted diaphyseal intramedullary rods were used in all patients and were not cemented. Metal wedges and augments were used to fill osseous defects when necessary. The average preoperative knee score, according to the rating scale of The Hospital for Special Surgery, was 49 points (range, 0 to 62 points). Postoperatively, the knee score improved to an average of 76 points (range, 0 to 97 points). Of the sixty-seven knees that had complete follow-up, fifty-six (84 percent) had an excellent or good result and five (7 percent) had a fair or poor result. In six (8 percent) of the seventy-six knees, the prosthesis failed, necessitating another revision. Failure was defined as removal or a recommendation for removal of the implant.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1994

Effects of epidural anesthesia on incidence of venous thromboembolism following joint replacement.

Deep vein thrombosis (DVT) and pulmonary embolism are serious complications following hip and knee replacement surgery. Both surgical procedures have significantly high postoperative rates of DVT. In total hip replacement, the rate of proximal thrombi tends to be higher. However, total knee replacement produces a high rate of calf thrombi and a higher overall rate of thrombosis. In a search for innovative ways to reduce the risk of thrombosis, three types of anesthesia were examined: general anesthesia, epidural anesthesia, and hypotensive epidural anesthesia in which a controlled hypotension is provided. The hypotension commonly exists with epidural anesthesia also, unless blood pressure is maintained with an agent such as ephedrine. When blood pressure is allowed to drop in a controlled fashion, hypotensive anesthesia is effected.

Anesthesia, Epidural↗

PubMed1994

Resection specimen analysis of tibial coverage in total knee arthroplasty.

To maximize tibial coverage during total knee arthroplasty, a study was performed to evaluate the morphology of the proximal tibia at the resection level and assess tibial coverage with respect to existing tibial implants. Unmagnified radiographs of 42 tibial resection specimens were produced and digitized with existing tibial implants from the asymmetrical Genesis and the symmetrical Insall-Burstein II and Press Fit Condylar total knee arthroplasty designs. The average total profile coverage ranged from 80.62% to 84.73%, whereas the average posteromedial coverage ranged from 76.05% to 82.09%. The shape of the tibia at the resection level was asymmetrical, and the overall tibial coverage was never greater than 85%. It appears that the actual shape of the tibial tray and the number of accommodating sizes provide the best ability of a total knee arthroplasty system to maximize tibial coverage, and not simply an asymmetrical or a symmetrical design.

Humans↗

PubMed1992

The significance of calf thrombi after total knee arthroplasty.

We reviewed the records of 1257 patients having 1625 total knee arthroplasties; all had pre-operative and postoperative perfusion lung scans and postoperative venograms which were classified as showing no thrombi, calf thrombi or proximal thrombi. Patients with calf thrombi were found to have a significantly greater risk for both symptomatic and asymptomatic pulmonary embolism compared with patients with no venographic thrombi. There were positive lung scans in 6.9% of patients with calf thrombi compared with 2.0% of patients with negative venograms (p < 0.001). Symptomatic pulmonary embolism occurred in 1.6% of patients with calf thrombi compared with 0.2% of patients with negative venograms (p = 0.034). The risk of pulmonary embolism was not significantly different between patients with treated proximal thrombi, and those with calf thrombi. Patients who develop deep-vein thrombosis despite prophylaxis are at increased risk for pulmonary embolism; these patients should receive treatment, or undergo follow-up studies to detect proximal propagation.

Aspirin↗