Patient Compliance with Extended Low Molecular Weight Heparin Injections following Hip and Knee Arthroplasty

Abstract

The use of extended duration thromboprophylaxis following hip and knee arthroplasty is becoming widespread. The aim of our study was to determine patient compliance with extended duration thromboprophylaxis using low molecular weight (LMWH) injections following hip and knee arthroplasty. 42 consecutive patients undergoing hip and knee arthroplasty were prospectively contacted during their fifth post operative week. A fully anonymised questionnaire was completed by each patient. All patients responded. One was excluded having been prescribed warfarin for pre existing atrial fibrillation. Twenty nine (71%) patients were discharged with the intention of self administering LMWH injections. Eight (20%) and four (9%) patients were discharged with the intention of administration by a relative or district nurse respectively. No patient required the person administering the injections to be changed after discharge from hospital. 90% (n=37) of patients reported not missing any doses. 10% (n=2) of patients missed one dose and 10% (n=2) missed two doses. Patient compliance with extended duration thromboprophylaxis using LMWH injections is extremely high. Oral thromboprophylaxis may be useful in the minority of patients requiring daily visits by a nurse to administer injections.

Patient Compliance with Deep Vein Thrombosis Prophylaxis after Total Hip and Total Knee Arthroplasty

“…Previous studies that have examined TKA and THA patients’ home compliance with DVT prophylaxis found 88-90% 10,11,20 of patients adhered to their medication regimens. Studies examining the compliance of patients at high risk for DVTs demonstrated similar compliance patterns.…”

“…Regarding reasons of noncompliance, the literature demonstrates that most patients forget to take 1-2 doses, 11 have difficulty purchasing the medication, lack proper instructions or lack someone available to administer the injection. 10 The literature characterizes patients who are compliant to be younger, employed and with a higher degree of education.…”

“…7-9 In the literature, compliance with home DVT prophylaxis for total hip and knee patients ranges from 88-90%. 10,11 During a quality improvement review of our arthroplasty service, a focus was placed on comparing our patient DVT compliance to the above described studies.…”

Post‐discharge patient‐reported non‐adherence to aspirin compared to enoxaparin for venous thromboembolism prophylaxis after hip or knee arthroplasty

“…A sample size calculation was informed by published data on nonadherence. Non-adherence for injected LMWH as VTE prophylaxis has been reported to range from 10% to 46% 5,7,9,10,15 and from 2% to 52% for oral prophylaxis. 9,10,12,[16][17][18] Based on these figures and on the hypothesis that non-adherence for aspirin would be lower, the sample size calculation used an expected non-adherence of 30% in the enoxaparin group and 15% in the aspirin group, a power of 80% and level of significance of 0.05, yielding a total sample size of 240 patients.…”