Definitions of the levels of evidence (I-V) and grades of recommendation (A-C) and are provided at the end of the "Major Recommendations" field.
The following recommendations are based on a systematic review of the literature and are evidence-based.
Recommendation 3.3: Chemoprophylaxis of patients undergoing hip or knee replacement
Recommendation 3.3.1:
Patients at standard risk of both pulmonary embolism (PE) and major bleeding should be considered for one of the chemoprophylactic agents evaluated in this guideline, including in alphabetical order: aspirin, low-molecular weight heparin (LMWH), synthetic pentasaccharides, and warfarin. (Level III, Grade B (choice of prophylactic agent), Grade C (dosage and timing)).
Note: The grade of recommendation was reduced from B to C for dosage and timing because of the lack of consistent evidence in the literature defining a clearly superior regime.
Recommendation 3.3.2
Patients at elevated (above standard) risk of PE and at standard risk of major bleeding should be considered for one of the chemoprophylactic agents evaluated in this guideline, including in alphabetical order: LMWH, synthetic pentasaccharides, and warfarin. (Level III, Grade B (choice of prophylactic agent), Grade C (dosage and timing)).
Note: The grade of recommendation was reduced from B to C for dosage and timing because of the lack of consistent evidence in the literature on risk stratification of patient populations.
Recommendation 3.3.3
Patients at standard risk of PE and at elevated (above standard) risk of major bleeding should be considered for one of the chemoprophylactic agents evaluated in this guideline, including in alphabetical order: aspirin, warfarin, or none. (Level III, Grade C)
Note: The grade of recommendation was reduced from B to C for dosage and timing because of the lack of consistent evidence in the literature on risk stratification of patient populations.
Recommendation 3.3.4
Patients at elevated (above standard) risk of both PE and major bleeding should be considered for one of the chemoprophylactic agents evaluated in this guideline, including in alphabetical order: aspirin, warfarin, or none. (Level III, Grade C)
Note: The grade of recommendation was reduced from B to C for dosage and timing because of the lack of consistent evidence in the literature on risk stratification of patient populations. No studies currently include patients at elevated risk of major bleeding and/or PE in study groups.
The following additional recommendations are based on the results of the objective American Academy of Orthopaedic Surgeons Consensus Process in which the work group members participated.
Recommendation 1.1
All patients should be assessed pre-operatively for elevated risk (greater than standard risk) of pulmonary embolism. (Level III, Grade B)
Recommendation 1.2
All patients should be assessed pre-operatively for elevated risk (greater than standard risk) of major bleeding. (Level III, Grade C)
Note: Grade of Recommendation reduced because of lack of consistent evidence on risk stratification of patient populations.
Recommendation 1.3
Patients with known contraindications to anticoagulation should be considered for vena cava filter replacement. (Level V, Grade C)
Recommendation 2.1
Patients should be considered for intra-operative and/or immediate postoperative mechanical prophylaxis. (Level III, Grade B)
Recommendation 2.2
In consultation with the anesthesiologist, patients should be considered for regional anesthesia. (Level IV, Grade C)
Recommendation 3.1
Postoperatively, patients should be considered for continued mechanical prophylaxis until discharge to home. (Level IV, Grade C)
Recommendation 3.2
Postoperatively, patients should be mobilized as soon as feasible to the full extent of medical safety and comfort. (Level V, Grade C)
Recommendation 3.4
Routine screening for deep venous thrombosis (DVT) or PE postoperatively in asymptomatic patients is not recommended. (Level III, Grade B)
Recommendation 4.1
Patients should be encouraged to progressively increase mobility after discharge to home. (Level V, Grade C)
Recommendation 4.2
Patients should be educated about the common symptoms of DVT and PE. (Level V, Grade B)
Note: The level of evidence is level V, expert opinion, but the strength of recommendation is B rather than C because patient education is consistent with the minimal expected standard of care for today's medical practices.
Of the fourteen recommendations listed above, only recommendations 3.3.1, 3.3.2, 3.3.3, and 3.3.4 are based on the systematic review of the literature conducted between August 2006 and March 2007 by The Center for Clinical Evidence Synthesis at Tufts New England Medical Center. The other recommendations contained in this guideline are based on consensus development methods only.
Definitions:
Levels of Evidence
Level I evidence is from high quality randomized clinical trials (e.g., a randomized trial comparing revision rates in patients treated with cemented and uncemented total hip arthroplasty).
Level II evidence is from cohort studies (e.g., revision rates in patients treated with uncemented total hip arthroplasty compared with a control group of patients treated with cemented total hip arthroplasty at the same time and institution).
Level III evidence is from case-control studies (e.g., the rates of cemented and uncemented total hip arthroplasty in patients with a particular outcome called "cases"; i.e. revised total hip arthroplasty, are compared to those who did not have outcome, called "controls"; i.e. non-revised total hip arthroplasty).
Level IV evidence is from an uncontrolled case series (e.g., a case series of patients treated with uncemented total hip arthroplasty).
Level V evidence is from expert opinion.
Recommendation Grades
A: Good evidence (Level I Studies with consistent finding) for recommending intervention.
B: Fair evidence (Level II or III Studies with consistent findings) for recommending intervention.
C: Poor quality evidence (Level IV or V) for recommending intervention.
