Clinical efficacy of mechanical thromboprophylaxis without anticoagulant drugs for elective hip surgery in an asian population
The Journal of Arthroplasty Vol. 24 No. 8 2009
Nobuhiko Sugano, MD, PhD,* Hidenobu Miki, MD,y Nobuo Nakamura, MD, PhD,z
Masaharu Aihara, MD,§ Kengo Yamamoto, MD,O and Kenji Ohzono, MD, PhD§
Abstract: To evaluate the clinical efficacy of mechanical thromboprophylaxis after elective hipsurgery, we reviewed 3016 patients who underwent hip surgery at 5 centers. Primary total hiparthroplasty (THA), revision THA, and pelvic or femoral osteotomies were performed in 2648, 298,and 70 patients, respectively. Epidural anesthesia, intraoperative calf bandage, early mobilization,and intermittent pneumatic compression postoperatively with additional use of elastic stockingswere the basic regimen for thromboprophylaxis. Postoperatively, no cases of fatal pulmonaryembolism (PE) were encountered. One symptomatic PE and 4 symptomatic deep vein thrombosiscases were identified, all of which were successfully treated using heparin and warfarin. By 6months, no deaths had occurred. We conclude that mechanical thromboprophylaxis withoutanticoagulant drugs is safe and effective for elective hip surgeries in our patient population. Keywords: venous thromboembolism, elective hip surgery, total hip arthroplasty, revision,osteotomy, intermittent pneumatic compression. 2009 Elsevier Inc. All rights reserved.
Pulmonary embolism (PE) is a serious complication after
only with mechanical prophylaxis after hip surgery in
various orthopedic surgery of the pelvis and lower
our Japanese patient population. We hypothesized that
extremities. Pulmonary embolism is thought to be
the rate of VTE shown as DVT, or PE using only the
caused by deep vein thrombosis (DVT) , and the
mechanical means for prophylaxis, would be less or
patients at highest risk of venous thromboemblism
equal to that shown in a Japanese registry There-
(VTE) are difficult to identify. Safe and cost-effective
fore, we studied a group of patients who underwent
prophylaxis against DVT is thus necessary to manage the
elective hip surgery retrospectively to determine
risk of postoperative VTE. Intermittent pneumatic
whether IPC prophylaxis was effective to prevent
compression (IPC) is one of the effective mechanical
methods for thromboprophylaxis Although the
efficacy of IPC has not been well reported in Asian
We looked at consecutive elective hip surgeries at 5
countries, we have noticed a low incidence of sympto-
affiliated institutes of our university between 2003
matic PE and DVT in patients who have been treated
and 2007 using the computer databases at eachinstitute. The medical records of these patients werereviewed as the candidates of this study. The recordsincluded history, age, sex, body mass index (BMI),
From the *Department of Orthopedic Medical Engineering, Osaka
University Graduate School of Medicine, Osaka, Japan; yDepartment of
physical status, diagnosis, anesthesia, patient position
Orthopedic Surgery, Osaka Medical Center, Osaka, Japan; zCenter of
on the operating table, type of surgery, type of
Arthroplasty, Kyowakai Hospital, Suita, Japan; §Department of Orthopedic
fixation, medication, laboratory data, and complica-
Surgery, Kansairousai Hospital, Amagasaki, Japan; and ODepartment ofOrthopedic Surgery, Hoshigaoka Koseinenkin Hospital, Hirakata, Japan.
tions in the hospitals were reviewed. Patients who
Submitted December 25, 2008; accepted May 11, 2009.
used heparin and warfarin for thromboprophylaxis
No benefits or funds were received in support of this study.
were excluded from this study. Patients who were
Reprint requests: Nobuhiko Sugano, MD, PhD, Department of
Orthopedic Medical Engineering, Osaka University Graduate School
taking aspirin before surgery stopped it 1 week before
of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
surgery and resumed it after surgery. These patients
2009 Elsevier Inc. All rights reserved.
were not excluded from the study. For mechanical
0883-5403/09/2408-0022$36.00/0doi:10.1016/j.arth.2009.05.015
prophylaxis against VTE, an A-V Impulse System foot
Mechanical Thromboprophylaxis Without Anticoagulant Drugs Sugano et al 1255
pump (Orthofix Vascular Novamedix, Andover, United
Table 2. Summary of Symptomatic VTE Cases
Kingdom) was used postoperatively for 1 to 2 days
until the patient started to walk with aids. Thigh-high
compression stockings were used for 2 weeks. Non-
steroidal antiinflammatory drugs were given for post-
operative pain control according to the complaints of
patients. Clinical signs of DVT such as pain and
tenderness in the calf or thigh, unilateral swelling,
erythema, and a positive Homan's sign were carefully
monitored, and when DVT was suspected, cardiovas-
cular physicians were consulted and ultrasonographywas performed. Patients were monitored for 3 weeksin the ward, and outpatient clinic data at the 6-monthfollow-up were reviewed.
stems were used in 218 cases, and cemented stems
To evaluate the efficacy of IPC prophylaxis against
were used in 64 cases. In the remaining 16 cases, only
PE in the subject of this study, we used the data of
cups were revised. In osteotomies, modified Chiari
the Japanese Guideline Committee for Prevention of
(dome) pelvis osteotomy was performed in 38 cases,
VTE accumulated from the Japanese literature as
rotational acetabular osteotomy was performed in 27
a control without prophylaxis, in which there were
cases, and femoral osteotomies were performed in 5
0.2% fatal PE (7/4504 cases) and 0.7% symptomatic
cases. In all procedures, the patient was placed in a
PE (32/4504 cases) in total hip arthroplasty (THA).
lateral position under general and epidural anesthesia.
We used χ2 test for categorized data and Mann-
Demographic characteristics of patients for each type of
Whitney U test (2 samples) or Kruskal-Wallis test (3
procedure are shown in Age and BMI differed
samples) for continuous data. P values less than .05
significantly among the 3 groups (P b .0001, Kruskal-
were considered to be statistically significant.
Wallis test), but no significant difference were seen insex ratio.
In the 3016 subjects of this study, there were no
cases of fatal PE. There was only one symptomatic
We identified 3025 patients as candidates for this
PE in a 70-year-old woman with hip osteoarthritis
study. Seven patients who were using warfarin for
developed on postoperative day 17 after cementless
cardiac disease before surgery and 2 patients with a
THA. She had dyspnea, which disappeared soon after
history of DVT were excluded from the study because
administration of heparin. A lung scan showed partial
we used heparin and warfarin for thromboprophylaxis
defect of the right lower lobe, but ultrasonography
in these patients. The subjects of this study comprised
showed no DVT. Four patients who underwent
3016 patients (2603 women, 413 men) in whom we
cementless THA developed symptomatic DVT between
used mechanical prophylaxis. There were 52 patients
postoperative days 7 and 20 (). Two of these
who were taking aspirin, and these patients were
patients developed proximal DVT, and the remaining
included in the study. Mean age at operation was 62
two experienced distal DVT on ultrasonography. All
years (range, 12-93 years). Mean BMI was 23.5 (range,
these patients were treated with heparin followed by
14.7-42.8). Primary THA was performed in 2648
warfarin medication for 6 months, and none devel-
patients, revision hip arthroplasty in 298 patients, and
oped symptomatic PE. Mean age of the 5 VTE cases
hip osteotomy in 70 patients. In primary THA, all cups
was 62.4 years, and mean BMI was 21.7, with no
were uncemented. Cementless stems were used in 2321
significant differences from the remaining VTE-free
cases. Cement stems were used in 214 cases. Cemented
patients (Mann-Whitney U test). We did not find
femoral head resurfacing was performed in the remain-
any risk factors related to VTE, including hemostatic
ing 113 cases. Simultaneous bilateral THA was per-
abnormalities (hypercoagulable state) or disorders of
formed for 48 patients. In revision THA, cementless
plasminogen and plasminogen activation in these 5patients. We were able to review the medical recordsof all 3016 patients at the 6-month follow-up, and
Table 1. Demography of Patients Receiving Each Type of
no deaths were identified. Moreover, no patients
developed new symptomatic VTE after 3 weeks. Incidences of fatal PE, symptomatic PE, and sympto-
matic DVT in this study were 0%, 0.03%, and 0.1%,
respectively. When we looked only at the group of
2648 patients who underwent THA, incidences were
relatively similar (0%, 0.04%, and 0.2%, respec-
tively). When comparisons were made with the data
1256 The Journal of Arthroplasty Vol. 24 No. 8 December 2009
of the Japanese Guideline Committee for Prevention
however, toward the use of a pharmacologic agent
of VTE accumulated from the Japanese literature ,
such as low-molecular-weight heparin, fondaparinux,
incidences of fatal PE (0%) and symptomatic PE
or warfarin, as some guidelines recommend antic-
(0.04%) were significantly lower in our study than
oagulants over mechanical methods such as IPC due to
in the control data, which reported 0.2% fatal PE (7/
the lack of supporting evidence . Our study may
4504 cases; P b .001, χ2 test) and 0.7% symptomatic
be seen as supporting the use of IPC in elective hip
PE (32/4504 cases; P b .05, χ2 test) in THA without
surgery as an effective prophylaxis against symptomatic
VTE without the worry of side effects.
We conclude that IPC mechanical thromboprophylaxis
without anticoagulant drugs is safe and effective for
elective hip surgery in our patient population.
Our subjects showed quite low incidences of fatal
PE, symptomatic PE, and symptomatic DVT with IPCprophylaxis after elective hip surgeries. In particular,
the incidences of fatal PE and symptomatic PE were
The authors would like to thank Dr T. Nishii, Dr
significantly lower with IPC prophylaxis than those in
T. Sakai, Dr M. Takao, Dr K. Tsuda, and Dr S. Nishihara in
THA without prophylaxis in a similar patient popula-
tion reported in the literature. Although 7 patientswho used anticoagulant drugs due to cardiac diseaseor who had a history of VTE were not included in
this study, the subjects in this study represented
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