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EDITORIALS: Duncan P Thomas Thromboprophylaxis after replacement arthroplasty BMJ 2001; 322: 686-687 [Full text]

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Bleeding risk with LMW heparins is still significant

Michael J O'Leary   (28 March 2001)

Thromboprophylaxis after replacement arthroplasty

David Maclennan   (31 March 2001)

Thromboprophylaxis after total joint replacement

Ryan Hamilton   (15 July 2001)

Bleeding risk with LMW heparins is still significant 28 March 2001
Michael J O'Leary, Staff Specialist in Intensive Care The St George Hospital, Kogarah, NSW, Australia Send response to journal: Re: Bleeding risk with LMW heparins is still significant	I am concerned that Dr Thomas' statement in his editorial that low molecular weight heparins do not need laboratory monitoring may be misinterpreted to suggest that these agents are intrinsically safer than unfractionated heparin or warfarin with respect to the risk of haemorrhagic complications of therapy. Whilst trials comparing low molecular weight heparins with unfractionated heparin have suggested that the bleeding risk may be slightly less with the former agents, the risk remains significant, especially in the elderly and those with co- morbidities such as malignancy or renal failure. It is not entirely correct to state that these agents do not require laboratory monitoring; monitoring is difficult, but is possible. The inability to easily monitor the effect of therapy on coagulation in at-risk patients may in fact make the use of unfractionated heparin or warfarin safer in these patients. We have now treated a number of patients in our Intensive Care Unit critically ill with retroperitoneal haemorrhage following low molecular weight heparin therapy, prescribed because it was safer and did not need monitoring. Unfortunately, life-threatening haemorrhage remains part of the risk / benefit analysis when low molecular weight heparin is prescribed.
Thromboprophylaxis after replacement arthroplasty 31 March 2001
David Maclennan, Senior House Officer in ENT Wrexham Maelor Hospital Send response to journal: Re: Thromboprophylaxis after replacement arthroplasty	Editor- While I would applaud the author for his attempts to clarify the thorny question of thromboprophylaxis after replacement arthroplasty (1) I would like to comment on two points. To assume that results of patients under going hip and knee replacements are interchangeable is a mistake; these operations are being performed on two different populations. Indeed one recent study (2) looking at the benefit of continuing low molecular weight heparin for twelve weeks post operatively found a significant reduction in the risk of thromboembolic disease after hip replacement but no such reduction in those who had undergone knee replacements. The other point is the statement “Most of the bleeding associated with anticoagulant therapy is, however, minor, with the incidence of major bleeding around 1%” the review (3) this figure comes from did not look specifically at patients post joint replacement. It Classified “major bleeding” as being stroke or haemorrhage causing death or requiring transfusion, this fails to take in to account that for patients with prosthesis even a minor bleed into the operative site can be a disaster if deep infection supervenes. Also it should not be forgotten that there are other recognised complications specific to this population such as spinal / epidural haematoma (4) and compartment syndrome (5). References 1 Duncan P Thomas. Thromboprophylaxis after replacement arthroplasty. BMJ 2001; 322: 686-687. 2 Comp PC, Spiro TE, Friedman RJ, Whitsett TL, Johnson GJ, Gardiner GA Jr, Landon GC, Jove M. Prolonged enoxaparin therapy to prevent venous thromboembolism after primary hip or knee replacement. Enoxaparin Clinical Trial Group. J Bone Joint Surg Am 2001 Mar;83-A(3):336-45. 3 Levine M, Raskob GE, Landefeld CS, Kearon C. Hemorrhagic complications of anticoagulant treatment. Chest 1998; 114: 511S-523S. 4 Zielinski CJ, Colwell CW, Collis DK, Paulson R, McCutchen JW,Bigler GT,Lutz S, Hardwick ME. Hematoma as a Complication of Enoxaparin Use. J Bone Joint Surg Am 2000 Sep:82-A(9):1362. 5 Nadeem RD, Clift BA, Martindale JP, Hadden WA, Ritchie IK. Acute compartment syndrome of the thigh after joint replacement with anticoagulation. J Bone Joint Surg Br. 1998 Sep;80(5):866-8.
Thromboprophylaxis after total joint replacement 15 July 2001
Ryan Hamilton, SHO III Orthopaedics Hairmyres Hospital, East Kilbride Send response to journal: Re: Thromboprophylaxis after total joint replacement	Dear Editor Thromboprophylaxis after total joint replacement I must agree with McDonald ( BMJ 23 June 2001, Thromboprophylaxis after replacement arthroplasty.) Thomas (BMJ 24 Mar 2001), concludes that anti-coagulants are the most effective way of preventing thromboembolism after total joint replacement, and in his reply to McDonald states that only warfarin or low molecular weight heparin are recommended. He also states that data concerning the use of foot pumps is sparse. I must point out that a recent American meta-analysis of thromboprophylaxis1, involving over 6000 patients showed that foot pumps had the lowest incidence of DVT and that they were comparable with low molecular weight heparin in prevention of pulmonary embolism, without the side effect of major bleeding. They also concluded that warfarin alone was ineffective as thromboprophylaxis. Yours sincerely Ryan Hamilton SHO III Orthopaedics 1. Meta-analysis of thromboembolic prophylaxis after total knee arthroplasty, Westrich et al, Journal of Bone and Joint Surgery 2000;82-B.