Cochrane Database of Systematic Reviews (Protocols) || Continuous passive motion therapy for preventing venous thromboembolism after total knee arthroplasty

Continuous passive motion therapy for preventing venous

thromboembolism after total knee arthroplasty (Protocol)

He ML, Xu YL, Xiao ZM, Li TS, Wu H, Liao J, Wu T, Li SZ

This is a reprint of a Cochrane protocol, prepared and maintained by The Cochrane Collaboration and published in The CochraneLibrary 2010, Issue 1

http://www.thecochranelibrary.com

Continuous passive motion therapy for preventing venous thromboembolism after total knee arthroplasty (Protocol)

Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.

http://www.thecochranelibrary.com

T A B L E O F C O N T E N T S

1HEADER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6CONTRIBUTIONS OF AUTHORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6DECLARATIONS OF INTEREST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6SOURCES OF SUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

iContinuous passive motion therapy for preventing venous thromboembolism after total knee arthroplasty (Protocol)


[Intervention Protocol]

Continuous passive motion therapy for preventing venousthromboembolism after total knee arthroplasty

Mao Lin He1, Ying Long Xu2, Zeng Ming Xiao1, Ting Song Li1, Hao Wu1, Jun Liao1 , Taixiang Wu3, Shu Zhen Li2

1Division of Spinal Surgery, 1st Affiliated Hospital of Guangxi Medical University, Nanning, China. 2Orthopaedics Department, 1st

Affiliated Hospital of Guangxi Medical University, Nanning, China. 3Chinese Cochrane Centre, Chinese EBM Centre, West China

Hospital, Sichuan University, Chengdu, China

Contact address: Mao Lin He, Division of Spinal Surgery, 1st Affiliated Hospital of Guangxi Medical University, 22 Shuangyong Road,

Nanning, Guangxi, 530021, China. [email protected]. [email protected].

Editorial group: Cochrane Peripheral Vascular Diseases Group.

Publication status and date: New, published in Issue 1, 2010.

Citation: He ML, Xu YL, Xiao ZM, Li TS, Wu H, Liao J, Wu T, Li SZ. Continuous passive motion therapy for preventing venous

thromboembolism after total knee arthroplasty. Cochrane Database of Systematic Reviews 2010, Issue 1. Art. No.: CD008207. DOI:

10.1002/14651858.CD008207.


A B S T R A C T

This is the protocol for a review and there is no abstract. The objectives are as follows:

The aim of this review is to determine the effectiveness of continuous passive motion therapy for preventing thrombosis in patients

after total knee arthroplasty.

B A C K G R O U N D

Description of the condition

With the ageing of the population, the prevalence of degenera-

tive joint diseases is increasing. In the United Kingdom, 10% of

people aged over 55 are affected with painful knee osteoarthritis

(Peat 2001). Total knee arthroplasty (TKA) is a common form of

orthopedic surgery, which can enhance the quality of life for pa-

tients. Currently in the United States, more than 400,000 TKAs

are performed every year, the number of annual TKA procedures

is expected to reach 3.48 million by the year 2030 (Kurtz 2007).

Venous thromboembolism disease (VTD) which consists primar-

ily of deep venous thrombosis (DVT) and pulmonary embolism

(PE) is a major and potentially fatal complication after TKA. Pa-

tients who receive joint replacement are particularly susceptible

because of a variety of physiological and mechanical factors in-

cluding:

1. Local vessel-wall damage occurring during surgery from the

operative procedure.

2. Blood becomes hypercoagulable from the sequelae of

responses to surgical stress.

3. Venous stasis occurs as a consequence of hyperviscosity of

the blood, prolonged immobility, and muscle weakness.

Patients who undergo joint arthroplasty often have a number

of characteristics that increase the risk of thromboembolism, in-

cluding advanced age, obesity, prolonged immobilization, varicose

veins, and cardiac dysfunction (Brander 2006). The greatest risk

for DVT is within the first week after surgery, but the risk re-

mains increased for several weeks after the procedure. A number

of studies suggest that the occurrence of DVT or PE will be be-

tween 40% and 84% of patients undergoing TKA (Lynch 1988;

1Continuous passive motion therapy for preventing venous thromboembolism after total knee arthroplasty (Protocol)


mailto:[email protected]

mailto:[email protected]

Stringer 1989). Most of the thrombi formed are small and have

little clinical consequence. Less than 2% of the patients develop

clinical PE, with fatal pulmonary embolism occurring in 0.1% to

0.7% of patients (Khaw 1993).

Description of the intervention

Because of the potentially life-threatening nature of these com-

plications, numerous prophylactic measures have been recom-

mended for these patients. Although pharmaceutical methods of

preventing DVT are regularly used, these thromboembolic com-

plications still occur in many patients. Furthermore, opponents

emphasize the high costs of universal prophylactic anticoagula-

tion, large numbers of clinically-silent DVTs, and chemoprophy-

laxis-related complications. There is substantial evidence in the lit-

erature that administration of anticoagulation chemoprophylaxis

places patients at risk of bleeding after TKA. The occurrence of

major bleeding complications after an elective total joint arthro-

plasty is regarded by most surgeons as unacceptable because of the

potential for the subsequent occurrence of more important com-

plications such as infection, wound healing problems, functional

disability, and loosening of the joint that have a high probability

of compromising the surgical outcome.

Since the usefulness of routine post-operative chemoprophylactic

treatment after TKA is divisive, early mobilization and mechan-

ical methods are of clinical interest. Continuous passive motion

(CPM) is an external motorized device, which enables a joint to

move passively throughout a preset arc of motion. The biologi-

cal concept of CPM was introduced by RB Salter in 1980 (Salter

1980).

The use of postoperative CPM for patients undergoing TKA was

first reported in the 1980s. Proposed advantages include increased

range of motion (ROM), a decrease in the length of hospital stay,

less postoperative pain, decreased requirement for manipulation,

decreased cost compared with physiotherapy alone, and potentially

a decrease in the rate of deep vein thrombosis.

How the intervention might work

Continuous passive motion is used in orthopedic surgery to pre-

vent joint stiffness and reduce the formation of hematoma and

edema, which may lead to fibrosis (O’Driscol 2000). Although

controversial, CPM has been used by many surgeons as part of the

standard postoperative management of patients with TKA.The ra-

tionale for the application of CPM is that it stimulates venous and

lymphatic flow and it maintains the range of the motion of the

joint. Venous stasis due to the absence of muscular contraction in

immobilized patients is an essential risk factor for VTD. The use of

CPM which by imitating muscular contractions and stimulating

the crural muscles is used in an attempt to accelerate venous blood

flow. The movement of the joint causes a measurable increase in

the venous blood flow producing the function of a physiological

pump. This may lead to a better dispersal of activated blood com-

ponents and dissolution of small thrombi attached to the venous

wall.

Why it is important to do this review

There are strong arguments for the effectiveness of CPM as pro-

phylaxis against thrombosis after TKA. The goal of the current

review is to find whether there is any additional benefit to using

CPM in the prevention of venous thromboembolism for patients

after TKA.

O B J E C T I V E S

The aim of this review is to determine the effectiveness of continu-

ous passive motion therapy for preventing thrombosis in patients

after total knee arthroplasty.

M E T H O D S

Criteria for considering studies for this review

Types of studies

We will include only randomized controlled trials (RCTs) in this

review.

Types of participants

People aged 18 years and older who have undergone TKA. Studies

with patients who present with DVT at baseline will be excluded.

Types of interventions

Any programs of CPM used in the patients after TKA, whether

combined with physical therapy or pharmacological prophylaxis.

Types of outcome measures

Primary outcomes

1. Proximal and distal DVT events diagnosed by venography

or sonography.

2. Pulmonary embolism diagnosed by V/Q lung scan, spiral

computed tomography (CT), or pulmonary angiography.

3. Death from all causes.



Secondary outcomes

1. Major bleeding (fatal bleeding or which involved a critical

organ, or required re-operation, or clinically overt bleeding

outside the surgical site, hemoglobin decrease > 2g/dl, or

requiring transfusion of more than two units of blood).

2. Minor bleeding (did not meet the above major criteria for

intervention).

3. Adverse effects.

4. Death.

Search methods for identification of studies

Electronic searches

The Cochrane Peripheral Vascular Diseases (PVD) Group will

search their Specialized Register and the Cochrane Central Reg-

ister of Controlled Trials (CENTRAL) in The Cochrane Library.The Specialized Register is maintained by the Trials Search Co-

ordinator and is constructed from weekly electronic searches of

MEDLINE, EMBASE, CINAHL, AMED, and through hand-

searching relevant journals. The full list of the databases, journals

and conference proceedings which have been searched, as well as

the search strategies used are described in the Specialized Register

section of the Cochrane PVD Group module in The Cochrane Li-brary.We will search the following databases using an appropriate ran-

domized controlled trials filter and the search terms described in

Appendix 1 (MEDLINE) and Appendix 2 (EMBASE).

Searching other resources

In addition, we will search the reference lists of identified trials.

There will be no restriction on language or publication status.

Letters, editorials, commentaries, reviews and lectures that do not

contain original research data will be excluded.

Data collection and analysis

Selection of studies

Two authors (He ML and Xu YL) will independently screen the

search results using the article titles and the abstracts (if available).

The full text of the selected articles will be retrieved and scruti-

nized to ensure that multiple publications from the same trial are

included only once. The same authors (He ML and Xu YL) will

then independently select articles for inclusion according to a stan-

dardized form to assess the eligibility of trials. Disagreements will

be resolved through discussion with the third author (Xiao ZM).

The trial authors will be contacted for clarification if it is unclear

whether a trial is eligible for inclusion. Excluded trials along with

the reason for exclusion will be listed.

A kappa statistic will be calculated for measuring agreement be-

tween two authors making simple inclusion and exclusion deci-

sions (Higgins 2008).

Data extraction and management

Two authors (He ML and Xu YL) will independently extract the

data using standard forms. Any differences will be resolved through

discussion with the third author (Xiao ZM). Attempts will be

made to obtain any missing data from the trial authors.

The following information will be extracted from included and

excluded studies:

• age;

• sex;

• thrombosis risk group to which participants belong;

• type of CPM used;

• duration of application of CPM;

• incidence of CPM;

• incidence of adverse events (PE, superficial vein thrombosis,

thrombophlebitis);

• investigations used to make the diagnosis of thrombosis and

adverse events.

Assessment of risk of bias in included studies

Two authors (He ML and Xu YL) will independently assess the risk

of bias of each trial described below and record the information

in a table and provide a narrative description in the text.

We will assess the methods used to generate the allocation se-

quence and conceal allocation as adequate, inadequate, or unclear

(Jüni 2001). We will record who was blinded in each trial (e.g.

participants, care providers, or outcome assessors). We will assess

the number of participants randomized into the trial and included

in the analysis as adequate (if more than 90%), inadequate (if less

than 90%), or unclear (if unclear how many participants were orig-

inally randomized into the trial). Disagreements will be resolved

by consensus, and trial authors will be contacted for clarification

if information is unclear.

Measures of treatment effect

For dichotomous outcomes, we will express results as relative risk

(RR) with 95% confidence intervals (CI). Data will be pooled

using the fixed-effect model but the random-effects model will

also be analyzed to ensure the robustness of the model chosen and

susceptibility to outliers.

For continuous scales of measurement we will use the mean dif-

ference (MD), or the standardized mean difference (SMD) if dif-

ferent scales have been used.



http://www.mrw.interscience.wiley.com/cochrane/clabout/articles/PVD/frame.html

http://www.mrw.interscience.wiley.com/cochrane/clabout/articles/PVD/frame.html

Unit of analysis issues

We will not analyze studies with non-standard designs except mul-

tiple treatment groups.

Dealing with missing data

Relevant missing data will be obtained from the authors of trials,

if possible. Evaluation of important numerical data such as the

number of screened, eligible and randomized patients as well as

intention-to-treat (ITT) and per-protocol (PP) populations will

be carefully performed. Drop outs, losses to follow up and with-

drawn study participants will be investigated. Issues of last-obser-

vation-carried-forward (LOCF), ITT and PP will be critically ap-

praised and compared with the specification of primary outcome

parameters and power calculation.

In the case of duplicate publications and companion papers of a

primary study, we will try to maximize the yield of information

by simultaneous evaluation of all available data. In cases of doubt,

the original publication (usually the oldest version) will obtain

priority.

Assessment of heterogeneity

Heterogeneity amongst trials will be investigated by: looking at

whether a graphical plot of the confidence intervals for the results

of each study overlaps; using a standard chi-square test with sig-

nificance set at P < 0.10; and using the I2 test statistic (> 50%

will be considered as substantial heterogeneity). We will attempt

to determine potential reasons for any heterogeneity found.

Assessment of reporting biases

Publication bias will be analyzed using the funnel plot method.

Funnel plot asymmetry will be assessed statistically. It is, however,

important to realize that publication bias is only one of a number

of possible causes of funnel-plot asymmetry.

Data synthesis

We will analyze the data using Review Manager 5.0. Results will

be combined unless clinical and methodological heterogeneity or

statistical heterogeneity (non overlapping confidence intervals) is

unreasonable. We will pool dichotomous data using the risk ra-

tio, and calculate the number needed to treat when appropriate.

If continuous data are summarized by arithmetic means and stan-

dard deviation data, then we will combine them using the mean

differences; where continuous data are summarized using geomet-

ric means, we will combine them on the log scale using the generic

inverse variance method, and report them on the natural scale.

The hazard ratio will be combined on the log scale using the generic

inverse variance method, for time-to-event data. We will present

all results with 95% confidence intervals. It is likely that we will

need to summarize the adverse event data using the risk difference

since events are likely to be rare.

The intention-to-treat principle will be applied. However, if there

is a discrepancy in the number randomized and the number ana-

lyzed in each group, we will calculate the percentage loss to follow

up in each group and consider using a different type of analy-

sis. We will use a fixed-effect meta-analytic model unless there is

statistically significant heterogeneity between trials, in which case

we will use a random-effects model. If heterogeneity proves to be

substantial, it may be unwise to perform a meta-analysis.

Subgroup analysis and investigation of heterogeneity

We will use subgroup analysis to explore possible sources of hetero-

geneity (e.g. participants, interventions and study quality). Het-

erogeneity among participants could be related to: age, outpatients

and inpatients with VTD.

Sensitivity analysis

Sensitivity analysis will be performed based on the four param-

eters of trial methodological quality. We will assess publication

bias using the funnel plot or other corrective analytical methods

depending on the number of included trials of this review.

A C K N O W L E D G E M E N T S

The editorial base staff of the Cochrane Peripheral Vascular Dis-

eases Group.



R E F E R E N C E S

Additional references

Brander 2006

Brander V, Stulberg SD. Rehabilitation after hip- and knee-

joint replacement. An experience- and evidence-based

approach to care. American Journal of Physical Medicine &

Rehabilitation 2006;85(11 Suppl):S98–S118.

Higgins 2008

Higgins JPT, Green S (editors). Cochrane Handbook

for Systematic Reviews of Interventions 5.0.0[updated

February 2008]. The Cochrane Collaboration. Available

from www.cochrane-handbook.org (accessed 10 August

2008), 2008.

Jüni 2001

Jüni P, Altman DG, Egger M. Systematic reviews in health

care: Assessing the quality of controlled clinical trials. BMJ

2001;323(7303):42–6.

Khaw 1993

Khaw FM, Moran CG, Pinder IM, Smith SR. The incidence

of fatal pulmonary embolism after knee replacement with

no prophylactic anticoagulation. Journal of Bone & Joint

Surgery - British Volume 1993;75(6):940–1.

Kurtz 2007

Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections

of primary and revision hip and knee arthroplasty in the

United States from 2005 to 2030. Journal of Bone & Joint

Surgery - American Volume 2007;89(4):780–5.

Lynch 1988

Lynch AF, Bourne RB, Rorabeck CH, Rankin RN, Donald

A. Deep-vein thrombosis and continuous passive motion

after total knee arthroplasty. Journal of Bone & Joint Surgery

- American Volume 1988;70(1):11–4.

O’Driscol 2000

O’Driscoll SW, Giori NJ. Continuous passive motion

(CPM): theory and principles of clinical application.

Journal of Rehabilitation Research & Development 2000;37

(2):179–88.

Peat 2001

Peat G, McCarney R, Croft P. Knee pain and osteoarthritis

in older adults: a review of community burden and current

use of primary health care. Annals of the Rheumatic Diseases

2001;60(2):91–7.

Salter 1980

Salter RB, Simmonds DF, Malcolm BW, Rumble EJ,

MacMichael D, Clements ND. The biological effect of

continuous passive motion on the healing of full-thickness

defects in articular cartilage. An experimental investigation

in the rabbit. Journal of Bone & Joint Surgery - American

Volume 1980;62(8):1232–51.

Stringer 1989

Stringer MD, Steadman CA, Hedges AR, Thomas EM,

Morley TR, Kakkar VV. Deep vein thrombosis after elective

knee surgery. An incidence study in 312 patients. Journal of

Bone & Joint Surgery - British Volume 1989;71(3):492–7.∗ Indicates the major publication for the study

A P P E N D I C E S

Appendix 1. MEDLINE search strategy

1. exercise therapy/ or exp motion therapy, continuous passive/

2. (passive adj5 motion).ti,ab.

3. Arthroplasty, Replacement, Knee/

4. (knee adj3 (arthropl$ or pros$ or surg$ or replac$)).ti,ab.

5. Knee/su [Surgery]

6. (1 or 2) and (3 or 4 or 5)



Appendix 2. EMBASE search strategy

1. kinesiotherapy/ or exp passive movement/

2. (passive adj5 motion).ti,ab.

3. exp knee arthroplasty/

4. knee/su [Surgery]

5.(knee adj3 (arthropl$ or pros$ or surg$ or replac$)).ti,ab.

6. (1 or 2) and (3 or 4 or 5)

H I S T O R Y

Protocol first published: Issue 1, 2010

C O N T R I B U T I O N S O F A U T H O R S

He ML conceived the idea for this systematic review and has co-ordinated its development. He will screen search results, select articles

for inclusion, assess trial eligibility, extract data and assess the risk of bias in the included studies.

Xu YL will screen search results, select articles for inclusion, assess trial eligibility, extract data and assess the risk of bias in the included

studies.

Xiao ZM will resolve disagreements in trial selection, assessment of trial quality and data extraction.

Li TS, Wu Hao, Liao Jun, Wu T and Li SZ will check and approve trial selection, assess trial quality, check and confirm data extraction,

enter data in RevMan and interpret the analysis.

D E C L A R A T I O N S O F I N T E R E S T

None known.

S O U R C E S O F S U P P O R T

Internal sources

• No sources of support supplied

External sources

• Chief Scientist Office, Scottish Government Health Directorates, The Scottish Government, UK.



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Cochrane Database of Systematic Reviews (Protocols) || Continuous passive motion therapy for preventing venous thromboembolism after total knee arthroplasty