Ibrahim J. Raphael

Aspirin: An Alternative for Pulmonary Embolism Prophylaxis After Arthroplasty?

BackgroundThe most effective agent for prophylaxis against venous thromboembolic disease after total joint arthroplasty (TJA) remains unknown. The paucity of literature comparing different methods of pulmonary embolism (PE) prophylaxis and fear of litigation make it difficult for surgeons to abandon the use of aggressive chemical prophylaxis.Questions/purposesWe compared the (1) overall frequency of symptomatic PE, (2) risk of symptomatic PE after propensity matching that adjusted for potentially confounding variables, and (3) other complications and length of stay before and after propensity matching in patients undergoing TJA at our institution who received either aspirin or warfarin prophylaxis.MethodsA total of 28,923 patients underwent TJA between January 2000 and June 2012 at our institution, had either aspirin (325 mg twice daily; 2800 patients) or warfarin prophylaxis (26,123 patients), and were registered in our institutional electronic database. The incidence of symptomatic PE, symptomatic deep vein thrombosis (DVT), hematoma formation, infection, wound complications, and mortality up to 90 days postoperatively was collected from the database. We performed multivariate analysis and 3:1 and 5:1 propensity score matching for comorbid and demographic variables.ResultsThe overall symptomatic PE rate was lower (p < 0.001) in patients receiving aspirin (0.14%) than in the patients receiving warfarin (1.07%). This difference did not change after matching. The aspirin group also had significantly fewer symptomatic DVTs and wound-related problems and shorter hospital stays, which did not change after matching.ConclusionsAfter publication of the American Academy of Orthopaedic Surgeons’ guidelines, some surgeons have utilized aspirin as thromboprophylaxis after TJA. Based on our findings from a large institutional database, aspirin offers suitable prophylaxis against symptomatic PE in selected patients.Level of EvidenceLevel III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

The Effect of Laminar Air Flow and Door Openings on Operating Room Contamination

We evaluate the association of laminar airflow (LAF) and OR traffic with intraoperative contamination rates. Two sterile basins were placed in each room during 81 cases, one inside and one outside the LAF. One Replicate Organism Detection and Counting (RODAC) plate from each basin was sent for culture at successive 30-minute intervals from incision time until wound closure. At successive 30-minute intervals more plates were contaminated outside than inside the LAF. A negative binomial model showed that the bacteria colony forming units (CFU) depended on whether there were any door openings (P=0.02) and the presence of LAF (P=0.003). LAF decreases CFU by 36.6%. LAF independently reduces the risk of contamination and microbial counts for surgeries lasting 90 minutes or less.

Obesity and Operative Time in Primary Total Joint Arthroplasty

Obesity has been associated with osteoarthritis and increased morbidity and mortality. Most joint arthroplasty patients have a high body mass index (BMI). Some surgeons are reluctant to operate on obese patients due to technical difficulties and the anticipated higher complication rate. The purpose of this prospective study was to determine whether obesity is associated with longer operative times. We attended 100 consecutive primary total joint arthroplasties. Patients were divided into four groups depending on their BMI: the normal group (BMI: 18 to 24.9 kg/m2), the overweight group (BMI: 25 to 29.9 kg/m2), the obese group (BMI: 30 to 39.9 kg/m2), and the morbidly obese group (BMI ≥ 40 kg/m2). Anesthesia type and time, duration of surgery, time needed for scrubbing, draping, and transferring the patient to the operating table were all documented. The mean operative time for total hip arthroplasty (THA) was significantly increased in morbidly obese patients (R2 = 0.197, p = 0.003). The mean scrubbing time for total knee arthroplasty varied with BMI (p = 0.028). Time to administer spinal anesthesia was significantly increased in morbidly obese patients (R2 = 0.1466, p = 0.018). Morbid obesity is associated with a significant increase in the time needed to administer spinal anesthesia and the overall time needed to perform a THA.

Timing of Symptomatic Pulmonary Embolism with Warfarin Following Arthroplasty.

The purpose is to determine the incidence and timing of pulmonary embolism for patients receiving warfarin for thrombo-prophylaxis following total joint arthroplasty (TJA). Current guidelines for duration of prophylaxis are nonspecific. Chemical prophylaxis carries the risk of bleeding and associated periprosthetic joint infection. We retrospectively studied 26,415 primary and revision TJA cases performed at our institution between 2000 and 2010. The overall 90-day rate of symptomatic PE was 1.07%. Fatal PE rate was 0.02%. Out of 283 documented symptomatic PE cases, 81% occurred within three postoperative days, 89% within one postoperative week, and 94% within two postoperative weeks. The risk of symptomatic PE appears to be highest during the first week after TJA. Efforts must be made to minimize risk during this period.

Proximal Deep Venous Thrombosis and Pulmonary Embolus Following Total Joint Arthroplasty

It has been proposed that prevention of deep venous thrombosis (DVT) will lead to a reduction in pulmonary embolism (PE). This retrospective comparative study examines the association between symptomatic proximal DVT (occurring at or proximal to the popliteal fossa) and PE in total joint arthroplasty (TJA) patients. We evaluated 1031 patients with DVT symptoms and 428 with PE symptoms. A total of 227 patients were evaluated for both. No statistically significant association found between developing PE and DVT within 90 days after TJA (P=0.94). Our findings raise into question the mechanical propagation theory. Formation of DVT and PE may be independent events in patients undergoing TJA. Evaluating the efficacy of thromboprophylaxis using DVT as end point may not reflect its efficacy for prevention of PE.

Pulmonary Embolism After Total Joint Arthroplasty: Cost and Effectiveness of Four Treatment Modalities

Pulmonary embolism (PE) treatment relies on therapeutic anticoagulation and may be associated with severe complications. Inferior vena cava filters (IVCFs) are used as an alternative/adjunct to anticoagulation. In this study we evaluate 4 treatment protocols for clinical efficacy and cost. We reviewed over 27,000 total joint arthroplasty (TJA) patients. We retrospectively identified 294 patients with a documented, symptomatic PE within 90 days of surgery. All patients were treated with warfarin postoperatively. In addition, for the acute management, patients were divided into four treatment groups: (1) IVCF only, (2) IVCF with heparin, (3) heparin only and (4) no treatment. Complication rates, hospital stay and PE recurrence are reported. Among patients who received warfarin, IVCF was associated with fewer complications and lower overall hospital costs compared to the use of heparin for the treatment of PE after TJA.

The Influence of Head Material on Polyethylene Wear

More than a century ago, remarkable physicians and innovators, from Themistocles Gluck to Austin Moore to Sir John Charnley, have made essential contributions to the development of hip arthroplasty procedures. Sir Charnley first introduced his modern low-friction hip prosthesis model in the early 1960s. The idea behind this concept was not only to use a small femoral head to decrease friction and therefore wear but also to allow the lubrication of bearing surfaces by native synovial fluid. Ever since, much research and effort have been invested in the fields of tribology and physics and have led to numerous improvements that make hip arthroplasty the success it is today.

Reply to the Letter to the Editor: Symptomatic Pulmonary Embolus After Joint Arthroplasty: Stratification of Risk Factors

(RE: Parvizi J, Huang R, Raphael IJ, Arnold WV, Rothman RH. Symptomatic pulmonary embolus after joint arthroplasty: stratification of risk factors. Clin Orthop Relat Res. 2014;472:903–912.) Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR ® or the Association of Bone and Joint Surgeons®.