Geoffrey H. Westrich

Prophylaxis against Deep Venous Thrombosis after Total Knee Arthroplasty. Pneumatic Plantar Compression and Aspirin Compared with Aspirin Alone

A prospective, randomized study was conducted to assess the efficacy of pulsatile pneumatic plantar compression for prophylaxis against deep venous thrombosis after total knee arthroplasty performed with use of regional anesthesia. One hundred and twenty-two patients (164 knees) who were scheduled to have a unilateral or a one-stage bilateral total knee arthroplasty were separately randomized to be managed with either aspirin alone or the pulsatile pneumatic plantar-compression device and aspirin. The prevalence of deep venous thrombosis was 27 per cent (twenty-two of eighty-one knees) in the group treated with pneumatic plantar compression compared with 59 per cent (forty-nine of eighty-three knees) in the patients managed with aspirin alone (the control group) (p < 0.001). A significant difference was also noted in the group that had had a unilateral arthroplasty (a prevalence of 27 per cent [eleven of forty-one knees] in the group treated with pneumatic plantar compression, compared with 67 per cent [twenty-six of thirty-nine knees] in that treated with aspirin alone; p < 0.006) and in the group that had had a one-stage bilateral procedure (a prevalence of 28 per cent [eleven of forty knees] in the group treated with pneumatic plantar compression, compared with 52 per cent [twenty-three of forty-four knees] in that treated with aspirin alone; p < 0.03). No proximal thrombi were noted in any patient who used the pulsatile pneumatic plantar-compression device, while the prevalence of proximal thrombosis in the popliteal or femoral veins was 14 per cent (twelve of eighty-three knees) in the group treated with aspirin alone (p < 0.0003). In the group treated with a unilateral procedure and aspirin alone the prevalence of proximal thrombosis was 13 per cent (five of thirty-nine knees; p < 0.02), while in the group treated with a bilateral procedure and aspirin alone it was 16 per cent (seven of forty-four knees; p < 0.01). Only in the patients who had had a unilateral procedure was use of the compression device associated with significantly less edema postoperatively than was use of aspirin alone. The change between the preoperative and postoperative circumferences of the thigh and leg was significantly less (9 ± 4.1 millimeters [mean and standard deviation] less for the thigh [p < 0.01] and 6 ± 3.9 millimeters less for the leg [p < 0.049]) with the compression device than with aspirin alone. In addition, there was significantly less mean drainage (98 ± 61.1 milliliters) in the group treated with a unilateral procedure and pneumatic compression, compared with that treated with a unilateral procedure and aspirin alone (p < 0.041). An internal timer of the compression device was used to assess the compliance of the patient with use of the device, and a relationship between deep venous thrombosis and the total duration of treatment with the device was found. The patients in whom deep venous thrombosis did not develop used the device for a mean of 96 ± 23.4 hours (range, sixty to 164 hours) postoperatively, or 19.2 ± 5.1 hours a day, while those in whom thrombosis developed used it for a mean of 67 ± 21.1 hours (range, twenty-six to 101 hours), or 13.4 ± 4.3 hours a day (p < 0.001). No untoward effects were noted in any patient who used the device. This study confirms the safety and efficacy of pulsatile pneumatic plantar compression and aspirin compared with aspirin alone and supports the use of mechanical compression for prophylaxis against deep venous thrombosis and for reduction of edema in patients who have had a total knee arthroplasty. In addition, we found a direct relationship between compliance with the use of this device and its efficacy in reducing deep venous thrombosis.

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 6001 patients were selected. The incidence of DVT was 53% (1701/3214) in the aspirin group, 45% (541/1203) in the warfarin group, 29% (311/1075) 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 (222/1901), 8.2% (101/1229) 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% (23/1800) 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 prophylatic 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.

Recent advances in venous thromboembolic prophylaxis during and after total hip replacement

Total hip replacement is an operation that is particularly prone to thromboembolic complications with potentially life-threatening consequences. Johnson et al., in a series of 7959 total hip replacements performed between 1962 and 1973, reported that the overall prevalence of pulmonary embolism was 7.89 percent and that of fatal pulmonary embolism was 1.04 percent51,52. Similarly, in 1974, Coventry et al. reported an overall prevalence of pulmonary embolism of 2.2 percent in a series of 2012 consecutive total hip replacements16. In a subset of sixty-two patients who had received no prophylactic anticoagulation, the prevalence of fatal pulmonary embolism was 3.4 percent. However, the average duration of the operation was 2.4 hours, the average blood loss was 1650 milliliters, and the average volume of blood transfused was 1144 milliliters. Prophylactic anticoagulation with warfarin was started five days after the operation. Patients were managed with bed rest for an average of one week before walking was allowed, and they were discharged at an average of three weeks after the operation17. During the last three decades, substantial advances have been made in the understanding of the pathophysiology and the prevention of venous thromboembolism associated with total hip replacement. The prevalence of fatal pulmonary embolism with contemporary operative techniques in the absence of anticoagulant prophylaxis was reported to be 0.5 percent after 1162 total hip replacements performed in the United Kingdom121. In North America, antithromboembolic prophylaxis and the combined use of predonated autologous blood5, an expeditious operation, and early mobilization appear to have lowered the rate of fatal pulmonary embolism even further, to 0.18 percent or less2,63,89,91,103,126. Importantly, an increased awareness of the intense activation of the clotting cascade, which occurs during …

THE INCIDENCE OF VENOUS THROMBOEMBOLISM AFTER TOTAL HIP ARTHROPLASTY : A SPECIFIC HYPOTENSIVE EPIDURAL ANESTHESIA PROTOCOL

We retrospectively reviewed all consecutive unilateral primary total hip arthroplasty (THA) procedures performed by 3 attending surgeons on the Arthroplasty Service at our institution from January 1, 1990, to December 31, 1993. All surgery was performed under a specific hypotensive epidural anesthesia protocol. Hypotensive epidural anesthesia at our institution provides a lower level of hypotension (mean arterial pressure of 50-60 mmHg) as compared to hypotensive anesthesia used more generally around the world (mean arterial pressure >70 mmHg). For each patient, hospital and postdischarge office records for a minimum of 3 months after surgery were reviewed for the type of postoperative screening test, the incidence of deep venous thrombosis (DVT), and the incidence of symptomatic pulmonary embolism (PE). Overall, 2,592 primary unilateral THAs were performed with 78.6% (2,037 of 2,592) of patients receiving a venogram. Our protocol for thromboembolic disease prophylaxis in these patients included aspirin postoperatively as well as antithromboembolic disease stockings and early ambulation (24-48 hours postoperatively). The 555 patients who did not receive venography were managed with a different protocol that included warfarin postoperatively as well as antithromboembolic disease stockings and early ambulation. This high-risk group consisted of patients who received warfarin preoperatively (ie, cardiac valve) or patients with a history of DVT who were to receive warfarin postoperatively, regardless of venography result. Overall, DVT was diagnosed in 10.3% (210 of 2,037) of patients who had a venogram. Of these patients who had venography, 2.3% (46 of 2,037) had an isolated proximal DVT; 6.0% (123 of 2,037), a distal DVT; and 2.0% (41 of 2,037), both a proximal and a distal DVT. Of the 87 cases of proximal DVT identified, 60.9% (53 of 87) were femoral DVT; 18.4% (16 of 87), popliteal DVT; and 20.7% (18 of 87), both femoral and popliteal DVT. Of the 164 distal DVT, 68.3% (112 of 164) were major calf DVT and 31.7% (52 of 164) were minor calf DVT. The overall incidence of major venous thrombosis (sum of proximal and major calf thrombi) was 9.8% (199 of 2,037) in patients who had venography. Ventilation-perfusion scanning was used selectively in patients symptomatic for PE. Overall, symptomatic PE was diagnosed by ventilation-perfusion scan in 1.0% (26 of 2,592) of patients, with 0.58% (15 of 2,592) of patients having an in-hospital PE. Of the 15 patients who had an in-hospital PE, 11 patients had a venogram, and only 3 of 11 were positive. Late symptomatic PE was defined from discharge (mean, 7 +/- 2 days) to 3 months after discharge from the hospital and occurred in 0.42% (11 of 2,592) of patients. One of the 11 late symptomatic PEs was fatal. In the overall study, this represents 0.04% (1 of 2,592) fatal PE. Of the 11 patients with a late symptomatic PE, 10 had venograms in the hospital, and all 10 were negative for DVT. Overall, in the patients with a positive venogram, the incidence of symptomatic PE was 1.4% (3 of 210), whereas in the patients with a negative venogram, the incidence of symptomatic PE was 0.44% (8 of 1,827). At our institution, patients who undergo primary THA performed with hypotensive epidural anesthesia, postoperative aspirin, antithromboembolic disease stockings, and early ambulation have a low risk for thromboembolic disease.

Arthroscopic release of the posterior cruciate ligament for stiff total knee arthroplasty.

Ten posterior cruciate ligament sparing total knee arthroplasties were studied in 9 patients who underwent arthroscopic posterior cruciate ligament release to improve intractable postoperative knee stiffness and pain. mean patient age was 64 years. Before posterior cruciate ligament release, the mean knee extension was 4 ° (0 °-10 °); mean knee flexion was 73.9 ° (40 °-110 °). The mean interval to posterior cruciate ligament release after primary total knee arthroplasty was 29 months. After release, mean extension was 1.3 ° (0 °-10 °) and mean flexion was 112 ° (range, 85 °-135 °). The average increase in flexion observed in the immediate postoperative period was 40.1 ° (25 °-60 °). At a mean followup of 20 months, mean extension was 1.5 ° (0 °-10 °), and mean flexion was 104.5 ° (70 °-125 °). At followup, the average increase in knee flexion was 30.5 ° (10 °-50 °). Before arthroscopic posterior cruciate ligament release, the average Knee Society knee and function scores were 70.9 and 71, respectively. At followup, the average Knee Society knee and function scores were 86.4 and 88, respectively. The Knee Society pain score improved from 33.5 preoperatively to 42 postoperatively. All patients reported subjective improvements in pain and stiffness. Eight patients (88%) reported satisfaction with the procedure. Two patients (22%) eventually required revision total knee arthroplasty.

Rotating hinge total knee arthroplasty in severely affected knees

A consecutive series of 24 knees in 21 patients who received a Finn rotating hinge for primary (nine knees) or revision (15 knees) total knee arthroplasty between August 1993 and January 1997 was reviewed. The average followup was 33 months (range, 21–62 months) for all patients in the study. Seventeen patients (20 knees) were followed up for more than 2 years. Twenty-four knees (21 patients) were categorized according to Knee Society scoring criteria: 37.5% (nine knees) were Category A, 25% (six knees) were Category B, and 37.5% (nine knees) were Category C. Using the Knee Society knee and function scores, clinical and radiographic results were assessed and outcome analysis was determined. The average Knee Society knee score improved from 44 points (range, 5–64 points) before surgery to 83 points (range, 45–95 points) after surgery; the average functional score according to the Knee Society system improved from 10 points (range, 0–35 points) before surgery to 45 points (range, 0–100 points) after surgery. Pain and function markedly improved after surgery. For treatment of the most severely affected knees with compromised bone and ligamentous instability, the Finn total knee replacement appears to be an acceptable option. As a rotating hinge design, the prosthesis at early followup provides excellent pain relief, restoration of walking capacity, and stabilization, without evidence of early mechanical failure.

Modular taper junction corrosion and failure: How to approach a recalled total hip arthroplasty implant

Corrosion at the modular neck-stem taper junction has become an increasingly important topic as several reports have identified this couple as a possible source for early failure with findings similar to failed metal-on-metal hip arthroplasties. Recently, two different modular stem systems from a single manufacturer were voluntarily recalled due to concerns of failure of the modular taper junction. We discuss how to approach the diagnosis and management of patients with these particular stem systems. We further reviewed the literature to evaluate whether this is a manufacturer-specific defect or indicative of a broader trend. Recent studies appear to implicate the basic design of the neck-stem taper junction, rather than a single manufacturer, which is at high risk for fretting and corrosion.

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.

CORRELATION OF THROMBOPHILIA AND HYPOFIBRINOLYSIS WITH PULMONARY EMBOLISM FOLLOWING TOTAL HIP ARTHROPLASTY: AN ANALYSIS OF GENETIC FACTORS

Background: The increased thromboembolic risk associated with total hip arthroplasty is multifactorial. We assessed whether the prevalence of abnormalities shown by newer genetic screening tests for thrombophilia and hypofibrinolysis was higher in patients in whom pulmonary embolism had developed after total hip arthroplasty than it was in matched control patients.Methods: Fourteen patients with documented pulmonary embolism after total hip arthroplasty and fourteen matched control patients who had undergone total hip arthroplasty without any clinical indication of thromboembolism were evaluated for risks of thrombophilia and hypofibrinolysis. Functional tests of hemostasis included evaluations of prothrombin time; activated partial thromboplastin time; levels of fibrinogen, serum homocysteine, protein C and S, and antithrombin III; activated protein-C resistance; and dilute Russell viper venom time. Molecular genetic testing was performed for factor-V Leiden, prothrombin promoter G20210A, methylenetetrahydrofolate reductase C677T, plasminogen activator inhibitor-1 4G/4G, and platelet glycoprotein IIb/IIIa A1/A2 or A2/A2 mutations.Results: The total number of genetic thrombophilic abnormalities identified was higher in the pulmonary embolism group (twenty-four abnormalities) than in the control group (fifteen abnormalities). Only patients with pulmonary embolism were found to have heterozygosity or homozygosity for the prothrombin G20210A mutation (four of fourteen patients; p = 0.05 compared with the control group) and a decreased antithrombin-III level (three of thirteen patients; p = 0.10 compared with the control group). Patients with pulmonary embolism were much more likely than control patients to have at least one thrombophilic abnormality: seven of fourteen patients with pulmonary embolism had a low antithrombin-III level or the prothrombin G20210A gene mutation compared with none of the fourteen in the control group (Fisher exact test, p < 0.01). The presence of the prothrombin G20210A gene mutation was significantly correlated with pulmonary embolism (r = 0.41, p = 0.03), as was the presence of least one abnormality (a low antithrombin-III level or the presence of the prothrombin G20210A gene mutation) (r = 0.58, p = 0.001).Conclusions: Genetic thrombophilia and hypofibrinolysis were more frequent in patients who had had pulmonary embolism after total hip arthroplasty than in those who had not. The presence of multiple genetic thrombophilic polymorphisms, particularly prothrombin G20210A and antithrombin III, rather than any single genetic prothrombotic abnormality, appears to signal an increased thromboembolic risk in patients undergoing total hip arthroplasty. Future refinements and availability of these tests will likely allow preoperative identification of patients with an increased genetic predisposition for thromboembolism.

Anterior Iliac Crest Bone Graft Harvesting Using the Corticocancellous Reamer System

Objective To evaluate the anterior iliac crest bone graft harvesting procedure using a corticocancellous acetabular reamer system. Design A total of 390 bone grafting procedures were reviewed using retrospective chart review. Two hundred twenty procedures were performed using the reamer system, and 170 were performed using traditional techniques (cortical strip, tricortical wedge, and cancellous trap door grafts). Setting The Hospital for Special Surgery, New York, New York. Participants Operative cases involving an anterior iliac crest bone graft procedure between January 1, 1991 and February 28, 1998. Main Outcome Measurements Complications were organized by the categories major, intermediate, and minor. Statistical analysis included assessment of comorbidity to determine risk factors that may be associated with a propensity for complications. Results Of the 390 patients reviewed, 13.1 percent (51 of 390) developed a total of seventy-one complications. Of the seventy-one complications, forty were reamer-associated and thirty-one were traditional method–associated complications. As compared with the traditional group, major morbidity was lower in the reamer group (0.9 percent [2 of 220] as compared with 1.8 percent [3 of 170] [p = 0.4]). Intermediate and minor morbidity were slightly higher in the reamer group than in the traditional group (5.9 percent [13 of 220] as compared with 5.3 percent [9 of 170] [p = 0.7] and 9.5 percent [21 of 220] as compared with 7.1 percent [12 of 170] [p = 0.4], respectively). Of the forty reamer-associated complications, 90 percent (36 of 40) resolved within ninety days (average 36.6 days). Of the thirty-one traditional method–associated complications, 74.2 percent (23 of 31) were resolved by 90 days (average 50.6 days). Using logistical regression analysis obesity (body mass index) (p = 0.03) and smoking (p = 0.03) were correlated with development of a complication. Furthermore, if a patient was obese and a smoker, the analysis predicted an 83 percent chance of developing a complication. Conclusions The reamer technique was found to be safe and efficacious while producing a large amount of autogenous corticocancellous bone graft. Overall complication rates for the reamer and the traditional groups were comparable. The corticocancellous reamer system represents an effective option for bone graft harvesting.