Accepted Manuscript A Randomized Controlled Trial of the Effectiveness of Continuous Passive Motion following Total Knee Replacement Janet A. Herbold, PT, MPH Kristen Bonistall, MS, MSW Marielle Blackburn, PT, DPT, OCS Jonila Agolli, PT, DPT Shawn Gaston, PT, DPT Chana Gross, PT, DPT Aleksandra Kuta, PT, DPT Suzanne Babyar, PT, PhD PII:
S0003-9993(14)00219-6
DOI:
10.1016/j.apmr.2014.03.012
Reference:
YAPMR 55782
To appear in:
ARCHIVES OF PHYSICAL MEDICINE AND REHABILITATION
Received Date: 5 December 2013 Revised Date:
6 March 2014
Accepted Date: 13 March 2014
Please cite this article as: Herbold JA, Bonistall K, Blackburn M, Agolli J, Gaston S, Gross C, Kuta A, Babyar S, A Randomized Controlled Trial of the Effectiveness of Continuous Passive Motion following Total Knee Replacement, ARCHIVES OF PHYSICAL MEDICINE AND REHABILITATION (2014), doi: 10.1016/j.apmr.2014.03.012. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF
Title: A Randomized Controlled Trial of the Effectiveness of Continuous Passive Motion
M AN U
SC
Janet A. Herbold, PT, MPH*‡ Kristen Bonistall, MS, MSW* Marielle Blackburn, PT, DPT, OCS* Jonila Agolli, PT, DPT† Shawn Gaston, PT, DPT† Chana Gross, PT, DPT† Aleksandra Kuta, PT, DPT† Suzanne Babyar, PT, PhD†
RI PT
following Total Knee Replacement
*Burke Rehabilitation Hospital Department of Outcomes and Clinical Research 785 Mamaroneck Avenue White Plains, NY 10605
TE D
†Doctor of Physical Therapy Hunter College/Graduate Center of City University of New York 425 East 25th Street New York, NY 10010
EP
‡Department of Physical Therapy Nova Southeastern University 3200 S, University Drive Fort Lauderdale, FL 33328
AC C
Janet A. Herbold, PT, MPH _ Corresponding Author Burke Rehabilitation Hospital 785 Mamaroneck Avenue White Plains, NY 10605 Work: 914-597-2357 Home : 914-630-0737 E-mail: [email protected]
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF
Acknowledgements
We would like to thank Dr. Mary Beth Walsh, CEO and Medical Director at the Burke
RI PT
Rehabilitation hospital for supporting our study, suggestion of analytic outcomes and editing the manuscript and Dr. B. Timothy Walsh for his statistical suggestions. We would also like to thank the therapist and staff of the orthopedic units and their supervisors for providing the structure to
AC C
EP
TE D
M AN U
SC
consistently measure the outcomes and track the CPM use by their patients.
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF 1
Title: A Randomized Controlled Trial of the Effectiveness of Continuous Passive Motion
2
following Total Knee Replacement
3
AC C
EP
TE D
M AN U
SC
RI PT
4
1
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF 5
Abstract
6 Objective: To determine the effects of using a Continuous Passive Motion (CPM) device for
8
individuals with poor range of motion following a total knee replacement (TKR) admitted for
9
post acute rehabilitation.
RI PT
7
11
Design: Randomized controlled trial.
12 Setting: An inpatient rehabilitation facility (IRF).
14
M AN U
13
SC
10
15
Participants: Adults (n=141) following TKR with initial active knee flexion of less than 75
16
degrees upon admission to the IRF.
TE D
17
Intervention: Two randomized groups: group 1 (n=71) patients received the conventional 3
19
hours of therapy per day and group 2 (n=70) received the addition of daily CPM use for 2 hours
20
throughout their length of stay.
21
EP
18
Main Outcome Measure(s): The primary outcome measure was active knee flexion range of
23
motion (ROM). Secondary outcome measures included: active knee extension ROM; an estimate
24
of function using the Functional Independence Measure (FIM); and Timed Up and Go Test
25
(TUG); girth measurement; and, self- reported Western Ontario and McMaster Universities
26
Osteoarthritis Index (WOMAC).
AC C
22
27
2
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF 28
Results: All subjects significantly improved from admission to discharge in all outcome
29
measures. However, there were no statistically significant differences in any of the discharge
30
outcome measures of the CPM group compared to the non-CPM group.
RI PT
31
Conclusion: CPM does not provide an additional benefit over the conventional interventions
33
employed in an inpatient rehabilitation facility for patient following TKR, specifically in patients
34
with poor initial knee flexion ROM following surgery.
35
SC
32
Keywords: Continuous passive motion; Total knee replacement; Functional recovery; Inpatient
37
rehabilitation facility; Rehabilitation
38
AC C
EP
TE D
39
M AN U
36
3
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF List of abbreviations:
41
TKR
total knee replacement
42
CPM
continuous passive motion
43
ROM
range of motion
44
ADL
activities of daily living
45
TUG
Timed Up and Go
46
WOMAC
Western Ontario and McMaster Universities Osteoarthritis Index
47
KSS
Knee Society Score
48
SF-12®
Short Form-12 Health Survey
49
PT
physical therapy
50
MEDPAC
Medicare Payment Advisory Commission
51
IRF
inpatient rehabilitation facility
52
SNF
skilled nursing facility
53
LOS
length of stay
54
FIM™
Functional Independence Measure
55
BMI
body mass index
56
AROM
active range of motion
57
ANCOVA
analysis of covariance
58
MCID
minimal clinically important difference
AC C
EP
TE D
M AN U
SC
RI PT
40
4
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF Total knee replacement (TKR) surgery is a common surgical procedure used to reduce pain and
60
improve function for individuals suffering from knee impairment associated with end stage
61
osteoarthritis. The number of total knee replacement surgeries will rise to 3.5 million in the
62
United States by the year 2030[1] which will create considerable demand for rehabilitation
63
services. Continuous passive motion (CPM) is a typical intervention added to the physical
64
therapy services in the acute care hospital to encourage early knee motion, but within post acute
65
rehabilitation its use is controversial.
SC
RI PT
59
66
The goal of rehabilitation following TKR is to facilitate the patient’s return to an active lifestyle.
68
Adequate range of motion (ROM) following surgery is linked to the performance of functional
69
activities. CPM treatment has been used since the early 1980’s to promote early mobilization and
70
improve knee flexion ROM. From a theoretical perspective, the passive exercise provided by the
71
CPM helps maintain ROM and reduces edema. Increased ROM enables active exercise and
72
greater strengthening.[2] Adequate ROM to perform many activities of daily living (ADL) has
73
been identified[3]: 90º to descend stairs, 105º to rise from a toilet or low chair [4], and 106º to
74
tie shoes.[5] The incidence of post operative stiffness appears to be 8% to 12%; that of complete
75
fibrous ankylosis after TKR is less than 1%.[6, 7] Although many factors affect ROM after
76
surgery, Bong et al identified preoperative risk factors such as limited ROM, underlying
77
osteoarthritis, prior knee surgery, and knee deformity (varus, valgus, and flexion
78
contractures).[8, 9]
TE D
EP
AC C
79
M AN U
67
80
Studies have reported conflicting results regarding the effectiveness of CPM. Early work
81
comparing CPM application following TKR to an immobilized knee postoperatively
5
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF demonstrated improvement in knee ROM [10] and wound healing with CPM. [11] Other studies
83
supported its use when applied immediately after surgery.[12-16] The positive results of
84
immediate CPM application were short term. An equal number of studies refuted these findings
85
and found CPM to be of little value in rehabilitation after TKR surgery.[17-25] These earlier
86
works demonstrating improvements in ROM and reduction in length of stay (LOS) frequently
87
compared the outcomes of patients using CPM to those with immobilized knees, but
88
immobilization is not contemporary practice. When additional outcomes were analyzed such as
89
calf swelling, wound healing, functional tests such as the Timed Up and Go (TUG), and
90
subjective measures such as the Western Ontario and McMaster Universities Osteoarthritis
91
Index(WOMAC), and Knee Society Score (KSS),[26] researchers similarly concluded that CPM
92
offers no additional benefit.[27] All initial studies were done in acute care hospital but were
93
conducted using a variety of ROM settings, treatment times, and days of use.
M AN U
SC
RI PT
82
TE D
94
To summarize the evidence, three systematic were conducted. Two reviews favored the use of
96
CPM in the initial postoperative phase following TKR[2, 28], a later Cochrane review did
97
not.[29] The Brosseau et al review suggested that CPM combined with physical therapy (PT)
98
intervention increased active knee flexion by 4° 2 weeks post knee replacement relative to PT
99
alone. The meta-analysis reviewed 20 randomized controlled trials of 1335 patients and reported
100
similar findings. CPM use in acute care hospitals may offer a small short term, but not long term
101
[30] benefit. Its use needs to be carefully weighed against the inconvenience and expense.
102
However, these reviews were conducted in acute care settings or in the home, and none involved
103
patients receiving rehabilitation at an IRF.
AC C
EP
95
104
6
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF One prospective study compared randomly assigned patients to either a CPM group or non-CPM
106
group and found no differences between groups.[31] A second IRF-based study compared a
107
control group receiving PT alone to 2 experimental groups; one received 35 minutes of CPM,
108
and the other 2 hours as an adjunct to PT treatment. The results did not support the addition of
109
CPM in the rehabilitation setting.[17] Prior work by the current authors using a matched cohort
110
design, reported no differences in ROM gain, the FIM™, ambulation device use, or the need for
111
homecare after discharge in 126 matched patients in an IRF setting.[32]
SC
RI PT
105
112
Although the preponderance of evidence does not support the benefit of CPM, no prior CPM
114
study conducted in an IRF selected patients most at risk for poor knee ROM following a TKR.
115
The purpose of this study was to determine the effects of using a CPM device for individuals
116
with poor range of motion following a TKR who were admitted for post acute rehabilitation.
M AN U
113
118
TE D
117 Method
119
Subjects: All patients transferred directly to the IRF within 5 days following their surgery
121
between November 2011 and November 2012 were assigned a primary therapist who assessed
122
the patient’s active knee flexion and extension ROM on the day of admission. Patients were
123
enrolled consecutively according to the inclusion criteria were: (1) patients transferred to an IRF
124
following a single knee replacement; (2) an etiology of osteoarthritis; (3) aged 40 to 80 years; (4)
125
an initial maximal knee flexion ROM between 45- 75 degrees of flexion; and, (5) a Body Mass
126
Index (BMI) < 40. Exclusion criteria were: (1) revision to a previous TKR; (2) bilateral TKR;
127
and, (3) co-morbid medical conditions that could interfere or complicate recovery such as stroke,
AC C
EP
120
7
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF Parkinson’s disease, or significant cognitive impairment. The Institutional Review Board
129
approved the study and written informed consent was obtained for each participant. Consented
130
subjects were randomly assigned to either the control or the experimental group based on their
131
unique, episode-specific account number. The control group received conventional PT. The
132
experimental group received conventional PT and daily CPM application for 2 hours. With a
133
medium effect size of 0.5 and a desired power of 0.80, the minimum acceptable sample size was
134
65 per group for a total of 130 subjects. Neither the patient nor the therapists were blinded to the
135
study group.
SC
RI PT
128
M AN U
136
We defined conventional therapy as three hours of physical and occupational therapy as part of
138
the interdisciplinary plan of care. The experimental group received an additional 2 hours of
139
CPM. On the day of admission, the CPM machine was set based on the maximum flexion
140
tolerated and the extension set at 0 degrees. The patients were instructed about how to stop the
141
machine if they experienced more than minimal discomfort.
TE D
137
142
During the initial PT evaluation, the patients were assessed on each of the study variables. The
144
discharge date and discharge destination were determined by the physician-led interdisciplinary
145
team who was blinded to the group assignment. On the day prior to discharge, the outcome
146
variables were reassessed. LOS was calculated by subtracting the discharge date from the
147
admission date to the IRF. One week after discharge, the WOMAC survey was mailed to the
148
patient’s home. Follow-up phone calls were made to facilitate survey return.
AC C
EP
143
149
8
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF 150
Measures: The outcome measures studied were active AROM, TUG score, knee girth, total
151
FIM scores, ambulation device at discharge, LOS, and the self reported WOMAC score. (1) AROM measurement was taken with a universal goniometer. Its axis was placed in line
153
with the center of the knee, the fixed arm aligned with the greater trochanter, and the
154
mobile arm aligned with the lateral malleolus. Both flexion and extension ranges of
155
motion was measured in the supine position. Inter-tester reliability for knee ROM was
156
previously reported as high for flexion (ICC= 0.89 - 0.98) and fair to good for extension
157
(ICC= 0.64- 0.92). [33, 34]
SC
(2) Timed Up and Go (TUG) is a functional test where the patient rises from an armed chair,
M AN U
158
RI PT
152
159
walks for 3 meters, turns, and walks back to resume a seated position. A standard set of
160
instructions to the patient were provided and the use of an ambulation device was
161
permitted.[35]
(3) Knee circumference was measured at the joint line and recorded in cm using a standard
TE D
162
tape measure. This measurement was used to determine girth as an indicator of swelling.
164
The inter-tester reliability ranged from ICC = 0.98-0.99 when both experienced and less
165
experienced therapists for girth measures a prior study. [36]
167 168 169
(4) Functional Independent Measurement (FIM™) is a well-standardized measure used to estimate the burden of care associated with 18 functional and cognitive items.[37-39]
AC C
166
EP
163
(5) Ambulation device was recorded as a nominal category and included no device, single cane, bilateral cane, crutches or walker.
170
(6) LOS was calculated by subtracting the discharge date from the IRF admission date.
171
(7) WOMAC is a self report measure assessing the patient’s perception of their pain,
172
stiffness and ability to perform ADL activities.[40]
9
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF The primary outcome of interest was maximum discharge knee flexion ROM. Secondary
174
outcomes included the discharge ambulation device, active knee extension, total FIM™ score,
175
the TUG, girth, LOS, and WOMAC scores. Additional patient characteristics such as age, sex,
176
race, and date of onset (surgery) were obtained.
177
Statistical analysis: For this randomized controlled trial, data were analyzed with the Statistical
178
Package for Social Sciences (SPSS), IBM version 21 for Windows. Descriptive statistics were
179
performed for all variables measured. To confirm group similarity, nominal data were analyzed
180
with a Fisher’s Exact Test and; continuous data were analyzed with independent t Tests.
181
Preliminary analyses evaluating the homogeneity-of-slope assumption indicated no significant
182
relationship between the covariates and the dependent variable. Therefore we used analysis of
183
covariance (ANCOVA) of discharge knee flexion and extension AROM, discharge total FIM
184
scores, discharge girth, and discharge TUG score with initial value of respective variables as the
185
covariates. The overall significance level was set at p < 0.05 but Bonferroni correction for the six
186
variables of interest yielded p
S0003-9993(14)00219-6
DOI:
10.1016/j.apmr.2014.03.012
Reference:
YAPMR 55782
To appear in:
ARCHIVES OF PHYSICAL MEDICINE AND REHABILITATION
Received Date: 5 December 2013 Revised Date:
6 March 2014
Accepted Date: 13 March 2014
Please cite this article as: Herbold JA, Bonistall K, Blackburn M, Agolli J, Gaston S, Gross C, Kuta A, Babyar S, A Randomized Controlled Trial of the Effectiveness of Continuous Passive Motion following Total Knee Replacement, ARCHIVES OF PHYSICAL MEDICINE AND REHABILITATION (2014), doi: 10.1016/j.apmr.2014.03.012. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF
Title: A Randomized Controlled Trial of the Effectiveness of Continuous Passive Motion
M AN U
SC
Janet A. Herbold, PT, MPH*‡ Kristen Bonistall, MS, MSW* Marielle Blackburn, PT, DPT, OCS* Jonila Agolli, PT, DPT† Shawn Gaston, PT, DPT† Chana Gross, PT, DPT† Aleksandra Kuta, PT, DPT† Suzanne Babyar, PT, PhD†
RI PT
following Total Knee Replacement
*Burke Rehabilitation Hospital Department of Outcomes and Clinical Research 785 Mamaroneck Avenue White Plains, NY 10605
TE D
†Doctor of Physical Therapy Hunter College/Graduate Center of City University of New York 425 East 25th Street New York, NY 10010
EP
‡Department of Physical Therapy Nova Southeastern University 3200 S, University Drive Fort Lauderdale, FL 33328
AC C
Janet A. Herbold, PT, MPH _ Corresponding Author Burke Rehabilitation Hospital 785 Mamaroneck Avenue White Plains, NY 10605 Work: 914-597-2357 Home : 914-630-0737 E-mail: [email protected]
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF
Acknowledgements
We would like to thank Dr. Mary Beth Walsh, CEO and Medical Director at the Burke
RI PT
Rehabilitation hospital for supporting our study, suggestion of analytic outcomes and editing the manuscript and Dr. B. Timothy Walsh for his statistical suggestions. We would also like to thank the therapist and staff of the orthopedic units and their supervisors for providing the structure to
AC C
EP
TE D
M AN U
SC
consistently measure the outcomes and track the CPM use by their patients.
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF 1
Title: A Randomized Controlled Trial of the Effectiveness of Continuous Passive Motion
2
following Total Knee Replacement
3
AC C
EP
TE D
M AN U
SC
RI PT
4
1
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF 5
Abstract
6 Objective: To determine the effects of using a Continuous Passive Motion (CPM) device for
8
individuals with poor range of motion following a total knee replacement (TKR) admitted for
9
post acute rehabilitation.
RI PT
7
11
Design: Randomized controlled trial.
12 Setting: An inpatient rehabilitation facility (IRF).
14
M AN U
13
SC
10
15
Participants: Adults (n=141) following TKR with initial active knee flexion of less than 75
16
degrees upon admission to the IRF.
TE D
17
Intervention: Two randomized groups: group 1 (n=71) patients received the conventional 3
19
hours of therapy per day and group 2 (n=70) received the addition of daily CPM use for 2 hours
20
throughout their length of stay.
21
EP
18
Main Outcome Measure(s): The primary outcome measure was active knee flexion range of
23
motion (ROM). Secondary outcome measures included: active knee extension ROM; an estimate
24
of function using the Functional Independence Measure (FIM); and Timed Up and Go Test
25
(TUG); girth measurement; and, self- reported Western Ontario and McMaster Universities
26
Osteoarthritis Index (WOMAC).
AC C
22
27
2
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF 28
Results: All subjects significantly improved from admission to discharge in all outcome
29
measures. However, there were no statistically significant differences in any of the discharge
30
outcome measures of the CPM group compared to the non-CPM group.
RI PT
31
Conclusion: CPM does not provide an additional benefit over the conventional interventions
33
employed in an inpatient rehabilitation facility for patient following TKR, specifically in patients
34
with poor initial knee flexion ROM following surgery.
35
SC
32
Keywords: Continuous passive motion; Total knee replacement; Functional recovery; Inpatient
37
rehabilitation facility; Rehabilitation
38
AC C
EP
TE D
39
M AN U
36
3
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF List of abbreviations:
41
TKR
total knee replacement
42
CPM
continuous passive motion
43
ROM
range of motion
44
ADL
activities of daily living
45
TUG
Timed Up and Go
46
WOMAC
Western Ontario and McMaster Universities Osteoarthritis Index
47
KSS
Knee Society Score
48
SF-12®
Short Form-12 Health Survey
49
PT
physical therapy
50
MEDPAC
Medicare Payment Advisory Commission
51
IRF
inpatient rehabilitation facility
52
SNF
skilled nursing facility
53
LOS
length of stay
54
FIM™
Functional Independence Measure
55
BMI
body mass index
56
AROM
active range of motion
57
ANCOVA
analysis of covariance
58
MCID
minimal clinically important difference
AC C
EP
TE D
M AN U
SC
RI PT
40
4
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF Total knee replacement (TKR) surgery is a common surgical procedure used to reduce pain and
60
improve function for individuals suffering from knee impairment associated with end stage
61
osteoarthritis. The number of total knee replacement surgeries will rise to 3.5 million in the
62
United States by the year 2030[1] which will create considerable demand for rehabilitation
63
services. Continuous passive motion (CPM) is a typical intervention added to the physical
64
therapy services in the acute care hospital to encourage early knee motion, but within post acute
65
rehabilitation its use is controversial.
SC
RI PT
59
66
The goal of rehabilitation following TKR is to facilitate the patient’s return to an active lifestyle.
68
Adequate range of motion (ROM) following surgery is linked to the performance of functional
69
activities. CPM treatment has been used since the early 1980’s to promote early mobilization and
70
improve knee flexion ROM. From a theoretical perspective, the passive exercise provided by the
71
CPM helps maintain ROM and reduces edema. Increased ROM enables active exercise and
72
greater strengthening.[2] Adequate ROM to perform many activities of daily living (ADL) has
73
been identified[3]: 90º to descend stairs, 105º to rise from a toilet or low chair [4], and 106º to
74
tie shoes.[5] The incidence of post operative stiffness appears to be 8% to 12%; that of complete
75
fibrous ankylosis after TKR is less than 1%.[6, 7] Although many factors affect ROM after
76
surgery, Bong et al identified preoperative risk factors such as limited ROM, underlying
77
osteoarthritis, prior knee surgery, and knee deformity (varus, valgus, and flexion
78
contractures).[8, 9]
TE D
EP
AC C
79
M AN U
67
80
Studies have reported conflicting results regarding the effectiveness of CPM. Early work
81
comparing CPM application following TKR to an immobilized knee postoperatively
5
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF demonstrated improvement in knee ROM [10] and wound healing with CPM. [11] Other studies
83
supported its use when applied immediately after surgery.[12-16] The positive results of
84
immediate CPM application were short term. An equal number of studies refuted these findings
85
and found CPM to be of little value in rehabilitation after TKR surgery.[17-25] These earlier
86
works demonstrating improvements in ROM and reduction in length of stay (LOS) frequently
87
compared the outcomes of patients using CPM to those with immobilized knees, but
88
immobilization is not contemporary practice. When additional outcomes were analyzed such as
89
calf swelling, wound healing, functional tests such as the Timed Up and Go (TUG), and
90
subjective measures such as the Western Ontario and McMaster Universities Osteoarthritis
91
Index(WOMAC), and Knee Society Score (KSS),[26] researchers similarly concluded that CPM
92
offers no additional benefit.[27] All initial studies were done in acute care hospital but were
93
conducted using a variety of ROM settings, treatment times, and days of use.
M AN U
SC
RI PT
82
TE D
94
To summarize the evidence, three systematic were conducted. Two reviews favored the use of
96
CPM in the initial postoperative phase following TKR[2, 28], a later Cochrane review did
97
not.[29] The Brosseau et al review suggested that CPM combined with physical therapy (PT)
98
intervention increased active knee flexion by 4° 2 weeks post knee replacement relative to PT
99
alone. The meta-analysis reviewed 20 randomized controlled trials of 1335 patients and reported
100
similar findings. CPM use in acute care hospitals may offer a small short term, but not long term
101
[30] benefit. Its use needs to be carefully weighed against the inconvenience and expense.
102
However, these reviews were conducted in acute care settings or in the home, and none involved
103
patients receiving rehabilitation at an IRF.
AC C
EP
95
104
6
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF One prospective study compared randomly assigned patients to either a CPM group or non-CPM
106
group and found no differences between groups.[31] A second IRF-based study compared a
107
control group receiving PT alone to 2 experimental groups; one received 35 minutes of CPM,
108
and the other 2 hours as an adjunct to PT treatment. The results did not support the addition of
109
CPM in the rehabilitation setting.[17] Prior work by the current authors using a matched cohort
110
design, reported no differences in ROM gain, the FIM™, ambulation device use, or the need for
111
homecare after discharge in 126 matched patients in an IRF setting.[32]
SC
RI PT
105
112
Although the preponderance of evidence does not support the benefit of CPM, no prior CPM
114
study conducted in an IRF selected patients most at risk for poor knee ROM following a TKR.
115
The purpose of this study was to determine the effects of using a CPM device for individuals
116
with poor range of motion following a TKR who were admitted for post acute rehabilitation.
M AN U
113
118
TE D
117 Method
119
Subjects: All patients transferred directly to the IRF within 5 days following their surgery
121
between November 2011 and November 2012 were assigned a primary therapist who assessed
122
the patient’s active knee flexion and extension ROM on the day of admission. Patients were
123
enrolled consecutively according to the inclusion criteria were: (1) patients transferred to an IRF
124
following a single knee replacement; (2) an etiology of osteoarthritis; (3) aged 40 to 80 years; (4)
125
an initial maximal knee flexion ROM between 45- 75 degrees of flexion; and, (5) a Body Mass
126
Index (BMI) < 40. Exclusion criteria were: (1) revision to a previous TKR; (2) bilateral TKR;
127
and, (3) co-morbid medical conditions that could interfere or complicate recovery such as stroke,
AC C
EP
120
7
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF Parkinson’s disease, or significant cognitive impairment. The Institutional Review Board
129
approved the study and written informed consent was obtained for each participant. Consented
130
subjects were randomly assigned to either the control or the experimental group based on their
131
unique, episode-specific account number. The control group received conventional PT. The
132
experimental group received conventional PT and daily CPM application for 2 hours. With a
133
medium effect size of 0.5 and a desired power of 0.80, the minimum acceptable sample size was
134
65 per group for a total of 130 subjects. Neither the patient nor the therapists were blinded to the
135
study group.
SC
RI PT
128
M AN U
136
We defined conventional therapy as three hours of physical and occupational therapy as part of
138
the interdisciplinary plan of care. The experimental group received an additional 2 hours of
139
CPM. On the day of admission, the CPM machine was set based on the maximum flexion
140
tolerated and the extension set at 0 degrees. The patients were instructed about how to stop the
141
machine if they experienced more than minimal discomfort.
TE D
137
142
During the initial PT evaluation, the patients were assessed on each of the study variables. The
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discharge date and discharge destination were determined by the physician-led interdisciplinary
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team who was blinded to the group assignment. On the day prior to discharge, the outcome
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variables were reassessed. LOS was calculated by subtracting the discharge date from the
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admission date to the IRF. One week after discharge, the WOMAC survey was mailed to the
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patient’s home. Follow-up phone calls were made to facilitate survey return.
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ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF 150
Measures: The outcome measures studied were active AROM, TUG score, knee girth, total
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FIM scores, ambulation device at discharge, LOS, and the self reported WOMAC score. (1) AROM measurement was taken with a universal goniometer. Its axis was placed in line
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with the center of the knee, the fixed arm aligned with the greater trochanter, and the
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mobile arm aligned with the lateral malleolus. Both flexion and extension ranges of
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motion was measured in the supine position. Inter-tester reliability for knee ROM was
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previously reported as high for flexion (ICC= 0.89 - 0.98) and fair to good for extension
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(ICC= 0.64- 0.92). [33, 34]
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(2) Timed Up and Go (TUG) is a functional test where the patient rises from an armed chair,
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RI PT
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walks for 3 meters, turns, and walks back to resume a seated position. A standard set of
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instructions to the patient were provided and the use of an ambulation device was
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permitted.[35]
(3) Knee circumference was measured at the joint line and recorded in cm using a standard
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tape measure. This measurement was used to determine girth as an indicator of swelling.
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The inter-tester reliability ranged from ICC = 0.98-0.99 when both experienced and less
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experienced therapists for girth measures a prior study. [36]
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(4) Functional Independent Measurement (FIM™) is a well-standardized measure used to estimate the burden of care associated with 18 functional and cognitive items.[37-39]
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(5) Ambulation device was recorded as a nominal category and included no device, single cane, bilateral cane, crutches or walker.
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(6) LOS was calculated by subtracting the discharge date from the IRF admission date.
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(7) WOMAC is a self report measure assessing the patient’s perception of their pain,
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stiffness and ability to perform ADL activities.[40]
9
ACCEPTED MANUSCRIPT RCT on use of CPM in an IRF The primary outcome of interest was maximum discharge knee flexion ROM. Secondary
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outcomes included the discharge ambulation device, active knee extension, total FIM™ score,
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the TUG, girth, LOS, and WOMAC scores. Additional patient characteristics such as age, sex,
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race, and date of onset (surgery) were obtained.
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Statistical analysis: For this randomized controlled trial, data were analyzed with the Statistical
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Package for Social Sciences (SPSS), IBM version 21 for Windows. Descriptive statistics were
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performed for all variables measured. To confirm group similarity, nominal data were analyzed
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with a Fisher’s Exact Test and; continuous data were analyzed with independent t Tests.
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Preliminary analyses evaluating the homogeneity-of-slope assumption indicated no significant
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relationship between the covariates and the dependent variable. Therefore we used analysis of
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covariance (ANCOVA) of discharge knee flexion and extension AROM, discharge total FIM
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scores, discharge girth, and discharge TUG score with initial value of respective variables as the
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covariates. The overall significance level was set at p < 0.05 but Bonferroni correction for the six
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variables of interest yielded p
