Feature Article

Arthroscopy on Anticoagulated Patients: A Retrospective Evaluation of Postoperative Complications

David C. Flanigan, MD; Ryan Muchow, MS; John Orwin, MD; Ben Graf, MD

  • Orthopedics
  • February 2010 - Volume 33 · Issue 2:
  • DOI:

Abstract

Anticoagulation is commonly needed for multiple medical conditions. The indications to discontinue anticoagulation for a simple procedure are controversial. Other surgical subspecialties have shown that keeping patients on warfarin during a simple procedure is safe. The purpose of this retrospective study was to evaluate the postoperative complications encountered for patients undergoing simple arthroscopic procedures while on warfarin. We hypothesized that anticoagulated patients undergoing simple arthroscopic procedures would have few surgical bleeding complications.

Arthroscopic procedures performed over a 10-year period on warfarin-anticoagulated patients were retrospectively evaluated. Data collected included the procedure and orthopedic problem, the type of anesthesia, the medical condition requiring anticoagulation, the international normalized ratio (INR) at surgery, and all postoperative complications (bleeding, hematoma, delayed healing, prolonged postoperative course, infection, medical complication). Twenty-four patients met the inclusion criteria. All had abnormal INR levels at time of surgery. Four patients were operated on emergently for septic joints, and 20 patients had elective arthroscopic procedures (10 knees, 10 shoulders). There were no major intraoperative bleeding problems. Seven patients had minor postoperative surgical complications: 2 prolonged effusions and 5 prolonged ecchymosis. No medical complications were seen. Oral warfarin appeared to be a safe alternative to manipulating anticoagulation during the preoperative period for simple arthroscopic procedures. Minor bleeding complications consisting of ecchymosis were seen, but no medical complications were identified.

Anticoagulation is commonly required for multiple medical conditions, including cardiac arrhythmia, valve replacement, pulmonary embolism, deep venous thrombosis (DVT), and hypercoagulable disorders. At times, these patients require surgical intervention, and the management of their anticoagulation during the perioperative period is a coordinated effort. Historically, anticoagulation has been discontinued prior to any surgical procedure to prevent bleeding complications, with the timing of discontinuation dependent on the anticoagulation agent being used and recommendations of the patient’s internist and anesthesiologist.1-4

For simple surgical procedures, controversy exists as to whether the potential risks of bleeding complications outweigh the risks of medical complications arising from discontinuing warfarin during the perioperative period.5-8 Studies in multiple surgical subspecialties have addressed this controversy. Surveys have documented the increased occurrence of medical complications—including death, cerebral vascular accident, DVT, and pulmonary embolism—when patients have been taken off warfarin anticoagulation therapy perioperatively.9-11 Both prospective and retrospective reviews have shown that continuation of oral anticoagulation during various simple procedures is safe, with no or minimal increase in minor bleeding complications.6,12-22 Nothing has been written in the orthopedic literature regarding performing arthroscopic procedures in this patient population.

Arthroscopy is one of the most common procedures in orthopedics and often only requires small portal incisions for successful completion of the procedure. At our institutions, the 2 senior authors (B.G., J.O.) have continued patients on warfarin during the perioperative period for simple arthroscopic procedures of the shoulder and knee. The purpose of this study was to retrospectively evaluate patients who underwent simple arthroscopic procedures and remained on warfarin to determine postoperative complications.

Materials and Methods

The study received approval from our Institutional Review Board. Patients were identified who had undergone an arthroscopic shoulder or knee procedure by the 2 senior authors and who had an abnormal international normalized ratio (INR) of >1.3 during the past 10 years (1994-2004). Thirty-six patients met these criteria. Twelve were eliminated because they were taken off warfarin and placed on a low-molecular-weight heparin agent during the perioperative period, according to their internist’s or cardiologist’s recommendations. Chart review indicated this was the preference of the physician.

Inclusion criteria for the study included shoulder or knee arthroscopic procedure while on warfarin, abnormal INR (>1.4), and complete follow-up notes. Twenty-four patients met these inclusion criteria. The decision to remain on warfarin during the perioperative period was made by the surgeon after consultation of the patient’s internist or cardiologist stratification and discussion of risks with the patient.

The patients’ charts, consisting of all notes from clinicians and physical therapists for up to 1 year postoperatively or until discharged from orthopedic follow-up, were reviewed. Information gathered included the medical reason for anticoagulation, shoulder or knee injury/diagnosis, INR level at surgery, type of anesthesia, surgical procedure performed, and intraoperative and postoperative complications. The information was tabulated to determine any trends in complications.

Results

Among the 24 patients who met the inclusion criteria, the medical conditions that required anticoagulation were atrial fibrillation (50%), thromboembolism (DVT/pulmonary embolism; 29%), aortic valve replacement (17%), and cerebral vascular accident (4%). All patients with a history of thromboembolism had a previous symptomatic event. All patients continued warfarin anticoagulation during the perioperative period, and >50% of the patients had an INR level >2.0 on the day of surgery (Table 1).

Table 1: Patient International Normalized Ratio Levels on the Day of Surgery

Table 2: Arthroscopic Procedures Preformed on Anticoagulated Patients

Four patients (3 shoulders, 1 knee) underwent an emergent arthroscopic irrigation and debridement for a septic joint without reversal of their anticoagulation. Twenty patients (10 knees, 10 shoulders) had an elective arthroscopic procedure for their underlying conditions: meniscal tear (50%), external impingement and/or acromioclavicular arthrosis (15%), rotator cuff tear (10%), biceps tendonitis (10%), glenohumeral arthrosis/loose bodies (10%), and adhesive capsulitis (5%). Five patients underwent bone debridement as part of the procedure, and 2 patients were converted to open procedures.

The surgical procedures performed are identified in Table 2. All patients underwent a general anesthesia for the procedure. Three patients had an adjuvant interscalene regional block preoperatively for postoperative pain control (all shoulders). No complications were identified from the regional anesthesia. Hypotensive anesthesia was encouraged, as the patient’s medical condition would permit, to reduce intraoperative bleeding.

For shoulder procedures, an arthroscopic inflow pump system (87k Arthroscopy Fluid Control System; ConMed Linvatec, Largo, Florida) was used throughout the case, allowing control of pressure and flow to decrease bleeding. Standard anterior and posterior portals were used in all patients with minimal incisions (<1 cm). During the glenohumeral evaluation and treatment, a radiofrequency probe was used to coagulate all bleeding tissue as needed. Subacromial decompressions and arthroscopic Mumford procedures were performed with the aid of a lateral incision. Glycine irrigation fluid was used to improve conductivity during ablation of the soft tissue. For the cases converted to a mini-open rotator cuff repair, care was taken to meticulously coagulate all bleeders using a radiofrequency coagulation.

During knee procedures, no tourniquet was used. All procedures were performed using 3 standard portals. A gravitational fluid inflow system was used. If any bleeding occurred, a Snyder tip was used to coagulate the bleeding tissue prior to removal of the instruments. One patient had a drain placed; it was removed prior to discharge from the ambulatory center. All skin incisions were closed. The joint was injected with a mixture of 0.5% lidocaine with 1:200,000 epinephrine, 0.25% marcaine, and morphine.

All notes from physicians and therapists were reviewed postoperatively for any mention of complications, medical or surgical (Table 3). Seven patients (29%) had a minor surgical complication. Five patients had a prolonged ecchymosis defined as bruising that extended past the 6-week postoperative follow-up. Two patients had a prolonged effusion, which was defined as an effusion for >3 months in a patient who had no effusion preoperatively. There seemed to be no relation to INR level or extent of surgery performed. No complications affected patients’ final outcomes. No serious bleeding complications were identified. No medical complications (DVTs, pulmonary embolisms, cerebral vascular accidents, or deaths) occurred in the studied population.

Table 3: Complications in Patients on Warfarin During Surgical Procedure

Discussion

Many underlying medical conditions require anticoagulation to protect patients from complication. Warfarin is the most common agent for long-term anticoagulation therapy. Warfarin competitively inhibits the action of vitamin K, blocking the hepatic formation of factors II, VII, IX, and X. Adequate levels of these factors may not be present until the prothrombin time/INR level is within normal limits, placing the patient at increased risk for bleeding complications.23 A concern is that while patients on warfarin have a higher risk of bleeding complications, discontinuation of warfarin may result in a higher risk of thromboembolic events and serious medical complications.

Current recommendations are to discontinue warfarin 4 to 5 days before the planned surgical procedure, although this remains controversial.2,4,5,24-26 In patients undergoing a general anesthetic for a low-risk procedure, oral anticoagulation may be maintained.2 According to the American Society of Regional Anesthesia and Pain Medicine Second Consensus Conference on Neuraxial Anesthesia and Anticoagulation, oral warfarin anticoagulation should be stopped and INR levels normalized prior to any neuraxial (spinal, epidural) anesthetic.27 Although the complication of spinal hematoma is rare, it can have devastating effects in these patients.24,27-30 The protocol for extremity regional anesthesia in anticoagulated patients is less defined.

Some subspecialties have continued warfarin during the perioperative period for simple surgical procedures to decrease the small chance of a complication arising from the medical condition requiring anticoagulation. Case reports and surveys have shown that medical complications such as cerebral vascular accidents, pulmonary embolisms, DVTs, and even deaths have occurred in these patients when warfarin has been stopped preoperatively.10,11,18,31-33 In ophthalmology, continuing warfarin for cataract surgery has been shown to be safe with no major bleeding or site-threatening complications.13,15,16,18,34 In plastic and dermatologic surgery, Mohs procedures and excisional procedures can be effectively performed without stopping warfarin, with only minor bleeding complications.35-38 Dental surgery has likewise shown that the risk of bleeding is minor and controllable in simple procedures and dental extractions.14,19,21,22,31,39 Finally, a meta-analysis of complications in simple procedures across several subspecialties has found the risk of bleeding complications to be minimal if warfarin is continued.40 Conversely, the risk of medical complications arising from a thromboembolic event if warfarin is withheld may be substantially higher than the expected risk for this patient population.31,33,40

Currently, there are no American Academy of Orthopedic Surgeons position statements for the treatment of anticoagulated patients undergoing arthroscopy or perioperative management of anticoagulated patients. The Academy has issued Clinical Guidelines on Prevention of Symptomatic Pulmonary Embolism in Patients Undergoing Total Hip or Knee Arthoplasty.41 These guidelines have little carryover to arthroscopic procedures and have been debated by the American College of Chest Physicians.42 Common practice has been to discontinue warfarin and manage perioperative anticoagulation with various methods: no treatment, low-molecular-weight heparin, or heparin.43 Unfortunately, there is no standard of care for perioperative management of anticoagulation for minimally invasive procedures.

Arthroscopy is the most frequently performed orthopedic surgery today. Using small (<1 cm) skin incisions, much can be performed with these limited portal incisions. The procedures can be simple (eg, loose body removal, partial meniscectomy, debridement) to more complex (eg, anterior cruciate ligament reconstruction, meniscal repair, arthroscopic superior labral anterior-posterior repair, arthroscopic Bankart repair, arthroscopic rotator cuff repair). Typically, simple arthroscopic procedures can be accomplished with little to no bleeding.

The incidence of thromboembolism after arthroscopy is low but variable in the literature. In a meta-analysis of 684 patients in 6 studies, the incidence of DVT in unprophylaxed patients averaged 9.9%, with a proximal DVT incidence of 2.1%.44 This is contrasted by larger patient population studies where the incidence has been found to be lower. In a recent study following >27,000 arthroscopic knee procedures, the incidence of DVT and pulmonary embolism was 0.24% and 0.16%, respectively.45 A case series of shoulder arthroscopies reported a low prevalence (0.42%) of DVT/pulmonary embolism after shoulder arthroscopy.46

In this study, all patients continued warfarin during the perioperative period. The INR levels were all >1.4, the minimal level necessary for acceptable coagulation. Both elective and emergent procedures were performed. Most were simple arthroscopic procedures with minimal risk of bleeding, but 5 cases (21%) were more extensive, including bone debridement (subacromial decompressions and Mumfords) and mini-open rotator cuff repairs. Only minor surgical complications were seen in these patients, consisting of prolonged ecchymosis and effusions in 29%. None of these complications affected the final outcome of the patient. No medical complications arising from their underlying medical conditions requiring anticoagulation were noted. Therefore, this study suggests that the continuation of warfarin in these patients had minimal risk of significant bleeding complications and may have helped prevent serious medical complications such as DVT, pulmonary embolism, or stroke.

The 2 senior authors paid close attention to obtaining meticulous hemostasis intraoperatively. A combination of hypotensive anesthesia, inflow pump systems, and radiofrequency coagulation has been used to help reduce the chance of intraoperative and postoperative bleeding. Previous studies have indicated that the INR level may influence bleeding complications. It has been suggested that INR levels <2.5 carry the lowest risk, 2.6 to 3.5 carry a moderated risk, and >3.5 carry a higher risk of bleeding complications.27 In this small patient study, no association was evident, but the majority of INR levels were <3.0.

This study has several limitations. As a retrospective review, it cannot be compared to a control group to determine if the minor bleeding complications are different than the normal population. The numbers in the study are small, as to be expected in this subgroup of anticoagulated patients requiring arthroscopic surgery. Therefore, it is difficult to draw a strong conclusion due to the sample size. Further research is needed to determine if this is an appropriate alternative during the perioperative period. Also, this study relied on the information noted in the patient’s chart. Finally, it does not provide an outcome measure other than the absence of medical complications to determine what effect continuation of warfarin may have had on the patient’s postoperative rehabilitation or final outcome.

This study provides preliminary support that continuing patients on warfarin during the perioperative period may be safe. Some minor bleeding complications occurred but did not affect patient outcome. No medical complications were seen in this group. Due to the small sample size, these observations do not warrant a change from the current standard of care in the community. Continued thought and discussion and further larger studies are needed to determine the best way to optimize the perioperative management of patients on anticoagulation therapy.

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Authors

Dr Flanigan is from the Sports Medicine Center, Ohio State University, Columbus, Ohio; and Mr Muchow and Drs Orwin and Graf are from the University of Wisconsin, Madison, Wisconsin.

Drs Flanigan, Orwin, and Graf and Mr Muchow have no relevant financial relationships to disclose.

Correspondence should be addressed to: David C. Flanigan, MD, Sports Medicine Center, Ohio State University, 2050 Kenny Rd, Ste 3100, Columbus, OH 43221 (david.flanigan@osumc.com).

doi: 10.3928/01477447-20100104-8

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