Continuous Passive Motion Following Total Knee Arthroplasty in People With Arthritis

What Is Known

• Despite the wide and continuous controversy, continuous passive motion (CPM) has been used by many surgeons as part of the standard postoperative management of patients with TKA for knee osteoarthritis.

What Is New

• Based on the available high-level evidences from randomized controlled trials, this study failed to demonstrate a discernable treatment effect of the application of CPM device in patients operated with TKA for osteoarthritis, with respect to the postoperative outcomes including the knee range of motion (ROM; knee extension, flexion, or full ROM), knee function, knee girth, and pain symptom. Thus, there is at this stage no indication for CPM procedures in patients operated with TKA as a standard postoperative care.

Total knee arthroplasty (TKA) has become a very common procedure for relieving the symptoms, including severe pain and dysfunction on knee movement, caused by advanced osteoarthritis around the knee.¹ It has been reported that the frequency of TKA procedure in end-stage knee osteoarthritis would be increased to as more as 3.5 million per year in the United States by 2030.² After the index operation procedure, to gain adequate range of motion (ROM) of the knee through rehabilitation is crucial as most activities require a minimum of 90-degree flexion.³ Previous studies have identified the minimum degrees of ROM to perform several daily activities, showing that 90, 105, and 106 degrees are required to complete the movements of descending stairs, rising from the toilet or low chair, and tie shoes, respectively.^3–5

The continuous passive motion (CPM) has been originally provided for patients operated with TKA, since the early 1980s.^6–9 The CPM is an external motorized device, which enables a joint to move passively throughout a preset arc of motion. It has been demonstrated that the CPM could enhance the cartilage healing and regeneration in rabbit model, compared with that of the articular without CPM use.^6–9 In 1982, Coutts et al.¹⁰ firstly performed a prospective clinical evaluation on the outcome of usage of CPM (applied for more than 16 hrs/d) after TKA, demonstrating a positive effect of CPM, which provided the patients an additional 22 degrees of knee flexion on discharge. After the publication of this study, the use of CPM after TKA increased dramatically, which has been estimated that as of 2002, in more than 17, 000 hospitals in 77 countries among 7 million patients, the CPM devices were provided routinely for rehabilitation.¹¹

In recent years, the application of CPM device in the short acute in-patient phase has brought out wide controversy.^12–23 Several studies proposed the advantages of CPM application including increased ROM, decrease in length of hospital stay, decrease in incidence of deep vein thrombosis, less postoperative pain, and decreased requirement for manipulation.^12–19 In many other studies, there was no additional benefit provided for patients delivered to rehabilitation with CPM.^20–23 In the matched cohort study of Herbold et al.,²⁴ they compared several clinical outcomes of patients rehabilitated with CPM and those without CPM after TKA, such as discharge active knee flexion ROM, Functional Independence Measure scores, discharge ambulation device, destination after discharge, and the need for home care services after the inpatient stay, demonstrating that no any significant difference between two groups was identified.

Despite the wide and continuous controversy, CPM has been used by many surgeons as part of the standard postoperative management of patients with TKA.^25–27 Moreover, many rehabilitation centers continuously apply the CPM devices without knowing of the cost-effectiveness consideration. In addition, application of CPM device may be related to significantly increased length of hospitalization.²³ Thus, the continuous uncertainty about the actual value of the CPM application after TKA operation has led to great perplexity for surgeons. This evidence-based study, therefore, set out to identify the effectiveness of the CPM application on the available clinical outcomes, such as knee ROM, pain score, time up and go, knee girth, and other knee function scores, based on evidence from recently published high-quality randomized controlled trials (RCTs).

MATERIALS AND METHODS

This study was performed according to the guidelines outlined in Preferred Reporting Items for Systematic Reviews and Meta-analysis statement (as shown in Appendix 1, Supplemental Digital Content 1, https://links.lww.com/PHM/B235).²⁸

Database Retrieval

The electronic platforms of PubMed, Embase, and CENTRAL were independently retrieved by two reviewers for potentially related records. The retrieval was restricted to the time from January 2000 to August 2020, to only include the recent publications for the consideration of the disparate operation technique and the variation on CPM device. In addition, the references of relative studies were screened, and potentially related studies were hand searched for possible inclusion. We showed the detailed searching strategies in Appendix 2 (Supplemental Digital Content 2, https://links.lww.com/PHM/B236).

Inclusion and Exclusion Criteria

The records screened from the database retrieval and hand searching were checked for duplicates and merged together after removal of the duplicates. Then, the titles and the abstracts of the remained records would be screened for potential eligibility, after which the full text of the studies would be further evaluated for the final inclusion.

The screening of the potential eligible records was according to the following inclusion criteria: (1) participants (P): patients operated with TKA for osteoarthritis around the knee; (2) intervention (I): patients were rehabilitated with CPM device at the postoperative period with the aim of accelerating the recovering of knee ROM; (3) comparison (C): patients were treated without CPM device postoperatively or with standardized physiotherapy (PT) alone; (4) outcomes (O): studies involved the following outcome variables for data analyses: active/passive knee extension/flexion/full ROM, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)-pain/physical function/stiffness/total score, visual analogue scale (VAS) pain score, knee girth, time up and go, Knee Society Scale (KSS)-function/knee score, and so on; (5) study (S): only well-designed RCTs, which was published in English, were eligible for the inclusion in this study.

Studies would be excluded from the current study following the criteria including: (1) patients operated by TKA for rheumatic arthritis or tumors around the knee; (2) nonrandomized clinical studies, animal studies, literature reviews, commentary studies and meta-analyses; and (3) duplicated studies.

Data Extraction

Two authors extracted the related data from the eligible studies independently, determined the cause of diversity in obtained information, and resolved disagreement through discussion. The extracted information including the following items:

• (1) Study characteristics: lead author, publication year, lead author's country, and study design;
• (2) Patients information: numbers of patients, dropped patients, male percentage, mean age of patients at operation and body mass index;
• (3) Intervention information: type of prostheses used for TKA and period, frequency, and detailed protocol of CPM;
• (4) Clinical outcomes: data about the active/passive knee extension/flexion/full ROM; and WOMAC-pain/physical function/stiffness/total score, VAS pain score, knee girth, time up and go, KSS-function/knee score, and all recorded complications.

Quality Assessment of Included Studies

The quality assessment of the included RCTs was performed based on the Cochrane Collaboration tool for assessing risk of bias. The tool included the following items: randomization sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, incomplete outcome data, selective reporting, and other bias.

Quantitative Data Analysis

As the variables involved in the current study were all displayed as the mean value and standard deviation, exploratory meta-analysis would be conducted for each variable using mean difference (MD) and the 95% confidence interval (95% CI) as the effect size. In case with significant heterogeneity (I ² > 50%), random-effect model would be used, while fixed-effect model was selected when presenting with excellent homogeneity.²⁹ Z test was used to test the significance of the pooled effect size.

For the continuous outcomes, subgroup meta-analyses were performed based on the follow-up periods, and pooling results were presented as line charts. Sensitivity analysis was conducted when three or more studies were included, and significant heterogeneity was presented, with the method of omitting each primary study to detect the stability of the pooling results. When five or more studies were included in a quantitative analysis, and publication bias test (Begg's and Egger's regression asymmetry tests, P < 0.050 and P < 0.100, were considered to be with significant publication bias, respectively) would be conducted.³⁰

Narrative synthesis of the significance on the difference of each outcome variable between CPM and non-CPM groups was performed using the method of thermodynamic diagram.

The statistical procedures were conducted using the "meta" package of R language. The statistical significance was defined at a two-sided P value of less than 0.05.

RESULTS

Study Searching and Selecting

The initial searching on the three databases yielded a total of 1024 records, and 6 additional records were searched by hand. After removal of 206 duplicates, 824 titles and abstracts were then assessed for eligibility. Then, 68 full-text articles were screened for final inclusion, remaining 10^{21–24,31–36} and 8^{22–24,31,33–36} RCTs included in the qualitative and quantitative syntheses, respectively. The detailed flowchart for study searching and selecting was shown in Figure 1.

FIGURE 1:

Flow chart for study retrieval and selection.

Summary of the Included Studies

Table 1 presents the summary of the included studies. A total of 10 RCTs involving 841 patients (415 in the CPM group and 426 in the non-CPM group) were included for eligibility. Nine studies^{21–24,32–36} presented the information about the sex distribution, showing that the male percentage was ranged from 15.8% to 50.0% with an overall male percentage of 32.6% (215 of 660 patients). The mean age at operation according to available data was ranged from 61.6 to 72.9 yrs. A total of 40 patients were lost to the final follow-up in these nine studies. The types of prostheses selected for TKA were available in five studies.^23,31–36Table 2 shows the detailed protocol for CPM in each trial, including the information about the period, frequency, and the increasing on ROM of CPM machine.

TABLE 1 - Summary of the included studies

Authors	Year	Country	Group	No. Patients	Male, %	Age	Drop Out	BMI	Prosthesis Type	Complications
Joshi et al.23	2015	United States	CPM	57	40.0	68.5 ± 7.8	11	29.8 ± 4.9	1 of 4 posterior-stabilized implants: Sigma Press-Fit Condylar, Vanguard, Optetrak Logic, or Persona	Acute quadriceps tendon tear (n = 1); deep hematoma (n = 1)
			No CPM	52	23.6	70.5 ± 8.7	8	30.6 ± 6.4		Deep wound dehiscence (n = 1)
Herbold et al.24	2014	United States	CPM	70	29.8	72.0 ± 7.0	0	NA	NA	NA
			No CPM	71			0
Chen et al.31	2012	China	CPM	68	NA	69.3 ± 6.8	0	NA	Legacy High Flex; Zimmer, Warsaw, Indiana	NA
			No CPM	69		69.3 ± 8.2	0
Alkire and Swank32	2010	United States	CPM	33	37.5	65.6	1	NA	Rotating platform implants (DePuy LCS or PFC-RP)	Urinary retention (n = 4); lumbar radiculopathy (n = 3); stitch abscess (n = 2); subcutaneous abscess (n = 1)
			No CPM	32	43.8	66.9	0
Bruun-Olsen et al.33	2009	Norway	CPM	30	27.0	68.0 ± 10.0	4 (in total)	NA	Type LCS with rotating platform	NA
			No CPM	33	33.0	71.0 ± 10.0
Lenssen et al.22	2008	The Netherlands	CPM	30	40.0	64.1 ± 8.1	0	NA	NA	n = 1
			No CPM	30	30.0	65 ± 9.1	0			n = 1
Leach et al.21	2006	United Kingdom	CPM	38	50.0	71.2 (53–84)	3 (in total)	NA	NA	NA
			No CPM	44	43.2	72.9 (52–89)
Baloch et al.34	2015	Pakistan	CPM	38	15.8	61.6 ± 9.1	0	31.9 ± 4.3	NA	NA
			No CPM	38	23.7	65.5 ± 7.9	0	33.6 ± 5.7
Chen et al.35	2000	United States	CPM	29	26.1	NA	6	NA	NA	NA
			No CPM	35	32.1		7
Wirries et al.36	2020	Germany	CPM	20	20.0	68.0 ± 9.2	0	31.3 ± 6.1	Genesis II, posterior stabilized, Smith and Nephew	n = 0
			No CPM	20	35.0	67.4 ± 9.2	0	28.2 ± 6.0		n = 0

BMI, body mass index; NA, not available.

TABLE 2 - Protocol for CPM

Author	Year	Period	Frequency	Protocol
Joshi et al.23	2015	Day 1 discharge	3 CPM sessions per day, each lasting 2 hrs	With ROM increased as tolerated
Herbold et al.24	2014	Throughout the length of stay	Daily CPM use for 2 hrs	The CPM machine was set based on the maximum flexion tolerated and the extension set at 0 degree
Chen et al.31	2012	Day 1 discharge (day 4)	3 times per day, each lasting for at least 2 hrs	70–100 degrees and 100 degrees at day 1 and the rest days for flexion, respectively
Alkire32	2010	Applied for 3 d (day 0–day 2)	3 times per day	Starting with flexion at 90–70 degrees, increasing extension by 10 degrees over 4 hrs for a total of 6 hrs per day
Bruun-Olsen et al.33	2009	Day 0 and day 1	Day 0: 2 hrs*2; Day 1: 2 hrs*3	Day 0: 70–100 degrees for flexion; Day 1: 0 degrees to maximum 100 degrees for flexion
Lenssen et al.22	2008	2 wks after surgery	4 hrs daily	After 5 mins of warm-up, ROM was set as tolerated
Leach et al.21	2006	Day 1 discharge	2 CPM sessions per day, each lasting 1 hr	Set at a range of 0–30 degrees, and increased by 10 degrees each day
Baloch et al.34	2015	Day 1 discharge	2 CPM sessions per day, each lasting 1 hr	Started from 0–30 degrees with 10 degrees daily increment
Chen et al.35	2000	Day 1 discharge	5 hrs per day at evening	Initially set from 0 degrees of extension to 10 degrees less than the measured passive knee flexion, and knee flexion was increased daily as tolerated
Wirries et al.36	2020	Day 1 discharge	2 times per day for 2 hrs daily	Adapted in dependence of the pain level by the physiotherapist

Figure 2 shows the result for risk of bias assessment for each trial. Among the seven risk of bias domains, the D2 (allocation concealment, selection bias) and D3 (blinding of participants and personnel, performance bias) were demonstrated to be with high risk of bias.

FIGURE 2:

Results for assessment of the risk of bias. The traffic lights with "x," "+," and "−" represent that the corresponding domains are of high, low, and unclear risk of biases, respectively. The bar plot shows the percentages of studies to be judges as high, low, or unclear risk of bias.

Results for Qualitative and Quantitative Syntheses

Figure 3 shows the thermodynamic diagram for the narrative synthesis of each outcome. The active knee extension, active knee flexion, active full ROM, passive knee extension, passive knee flexion, passive ROM, WOMAC-pain score, WOMAC-physical function score, WOMAC-stiffness score, WOMAC-total score, VAS pain score, time up and go, knee girth, KSS-function score, and KSS-knee score were assessed in 6, 7, 3, 3, 4, 2, 3, 3, 3, 4, 3, 2, 4, 2, and 2 studies, respectively, and were included in our qualitative synthesis. As a result, statistically significant differences were only reported for the active knee extension at 3 mos in the study by Joshi et al.²³ and 1 wk as well as 3 mos in the study by Bruun-Olsen et al.,³³ the passive knee extension at 1 wk and 3 months in the study by Bruun-Olsen et al.,³³ the passive knee flexion and passive full ROM at discharge in the study by Wirries et al.,³⁶ and the VAS pain score at 3 mos both in the study by Chen et al.³¹ and Bruun-Olsen et al.³³ No any other variable was found to be significantly different between the CPM and non-CPM groups at any follow-up point.

FIGURE 3:

Heat map showing the result of systematic review. In this plot, red and green boxes represent that the corresponding outcomes are nonsignificant or significant in the studies, respectively. Statistically significant differences were only reported for the following comparisons: (A) active knee extension at 3 mos in the study by Joshi et al.²³ and 1 wk as well as (B) 3 mo in the Bruun-Olsen et al.,³³ (C) passive knee extension at 1 wk and 3 mos in the study by Bruun-Olsen et al.,³³ the passive knee flexion (D) and passive full ROM (E) at discharge in the study by Wirries et al.,³⁶ and VAS pain score at 3 mos (F) in the study by Chen et al.³¹ No significant difference was shown in all of the other comparisons.

As most of the outcome variables were reported at several different follow-up points for dynamically assessing the effectiveness of the CPM application, continuous forest plots were generated to display the pooled results (MD as well as the 95% CI) in Figure 4. Data were available for 15 different outcomes at several time points, such as preoperation, discharge, day 1, 1 wk, 2 wks, 6 wks, 3 mos, and 6 mos. In general, most of the pools demonstrated statistically similar outcome between CPM and non-CPM groups. Exclusively, the active knee extension at 1 wk (MD = 3.00, 95% CI = 0.5 to 5.5, P = 0.019*), passive knee extension at 1 wk (MD = 3.00, 95% CI = 0.28 to 5.72, P = 0.031*), and 3 mos (MD = 3.00, 95% CI = 0.5 to 5.5, P = 0.019*) were shown to be significantly different between the two groups. The forest plot for the length of hospital stay was available in Supplementary Figure S1 (Supplemental Digital Content 3, https://links.lww.com/PHM/B237), demonstrating that no significant effect of CPM on reducing the length of hospital stay (MD = 0.64, 95% CI = −0.59 to 1.87, P = 0.309).

FIGURE 4:

Line chart showing the pooling results for outcomes at different follow-up points. The dotted line in the chart represents the nonsignificant line.

Table 3 shows the results of the meta-analyses for the clinical outcomes at different follow-up times. The number of studies included for synthesis, number of patients involved, pooled effect size, I ², effect model selected, and the P value of Z test were available. Random-effect model was selected for the pooling of 3-mo active knee extension, preoperative active knee flexion, 2-wk active full ROM, preoperative passive knee flexion, 3-mo VAS, and length of hospital stay. Among these, the preoperative active knee flexion and length of hospital stay were associated with more than three studies, and sensitivity analyses were performed to detect potential studies causing instability on the pooling results. Supplementary Figure S2 (Supplemental Digital Content 4, https://links.lww.com/PHM/B238) shows the sensitivity analyses for the two comparison, giving no study causing significant instability.

TABLE 3 - Results of the meta-analyses for clinical outcomes at different follow-up times

Outcomes	Included Studies	No. Patients	MD (95% CI)	I 2, %	Effect Model	Z Test, P
Active knee extension
Preop	322,23,33	232	−0.52 (−1.81 to 0.77)	0	Fixed	0.427
Discharge	222,24	201	0.63 (−0.29 to 1.55)	0	Fixed	0.177
Day 1	124	141	−0.10 (−1.21 to 1.01)	—	—	0.859
1 wk	133	63	3.00 (0.5 to 5.5)	—	—	0.019*
2 wks	122	60	−1.80 (−4.01 to 0.41)	—	—	0.111
6 wks	123	109	−0.20 (−1.18 to 0.78)	—	—	0.689
3 mos	223,33	172	0.86 (−2.95 to 4.66)	89	Random	0.659
Active knee flexion
Preop	422,23,33,34	308	0.36 (−4.91 to 5.62)	71	Random	0.895
Discharge	322,24,34	277	−1.50 (−3.25 to 0.26)	16	Fixed	0.095
Day 1	124	141	−2.30 (−4.81 to 0.21)	—	—	0.073
1 wk	133	63	2.00 (−5.17 to 9.17)	—	—	0.585
2 wks	122	60	3.20 (−1.26 to 7.66)	—	—	0.159
6 wks	123	109	−0.70 (−3.95 to 2.55)	—	—	0.673
3 mos	223,33	172	0.29 (−2.07 to 2.65)	17	Fixed	0.807
Active full ROM
Preop	322,23,31	306	−1.28 (−4.28 to 1.72)	35	Fixed	0.403
Discharge	122	60	−0.50 (−4.51 to 3.51)	—	—	0.807
2 wks	222,31	197	−0.38 (−3.18 to 2.42)	83	Random	0.790
6 wks	223,31	246	−1.85 (−4.32 to 0.61)	0	Fixed	0.141
3 mos	223,31	246	−0.04 (−2.05 to 1.96)	0	Fixed	0.966
6 mos	131	137	0.38 (−1.7 to 2.46)	—	—	0.721
Passive knee extension
Preop	222,33	123	−0.96 (−2.77 to 0.84)	0	Fixed	0.295
Discharge	222,35	124	−0.33 (−1.45 to 0.79)	5	Fixed	0.563
Day 1	135	64	−0.40(−2.41 to 1.61)	—	—	0.697
1 wk	133	63	3.00 (0.28 to 5.72)	—	—	0.031*
2 wks	122	60	−1.40 (−3.38 to 0.58)	—	—	0.167
3 mos	133	63	3.00 (0.5 to 5.5)	—	—	0.019*
Passive knee flexion
Preop	322,33,36	163	−2.85 (−8.41 to 2.71)	61	Random	0.315
Discharge	322,35,36	164	0.22 (−3.56 to 4.01)	67	Random	0.908
Day 1	135	64	0.00 (−6.99,6.99)	—	—	1.000
Day 3	135	64	−3.00 (−7.41 to 1.41)	—	—	0.182
1 wk	233,35	127	−0.18 (−3.70 to 3.34)	0	Fixed	0.921
2 wks	122	60	3.30 (−1.36 to 7.96)	—	—	0.165
3 mos	133	63	−4.00 (−12.02 to 4.02)	—	—	0.328
Passive full ROM
Preop	222,36	100	−1.57 (−12.84 to 9.69)	83	Random	0.784
Discharge	222,36	100	1.95 (−4.81 to 8.71)	83	Random	0.572
2 wks	122	60	4.70 (−0.44 to 9.84)	—	—	0.073
WOMAC-pain score
Preop	222,24	201	−0.27 (−1.29 to 0.74)	0	Fixed	0.597
Day 17	122	60	0.50 (−1.73 to 2.73)	—	—	0.661
6 wks	122	60	−0.60 (−2.55 to 1.35)	—	—	0.546
3 mos	122	60	−0.20 (−1.60 to 1.20)	—	—	0.779
WOMAC-physical function score
Preop	222,24	201	1.57 (−1.77 to 4.91)	0	Fixed	0.356
Day 17	122	60	3.80 (−2.23 to 9.92)	—	—	0.224
6 wks	122	60	0.30 (−5.18 to 5.78)	—	—	0.915
3 mos	122	60	−1.00 (−4.36 to 2.36)	—	—	0.560
WOMAC-stiffness score
Preop	222,24	201	−0.05 (−0.48,0.39)	0	Fixed	0.838
Day 17	122	60	0.20 (−0.66 to 1.06)	—	—	0.649
6 wks	122	60	0.60 (−0.24 to 1.44)	—	—	0.161
3 mos	122	60	0.20 (−0.56 to 0.96)	—	—	0.606
WOMAC-total score
Preop	322–24	310	2.86 (−0.62 to 6.35)	29	Fixed	0.107
Discharge	124	141	−3.10 (−7.89 to 1.69)	—	—	0.204
Day 17	122	60	4.50 (−3.67 to 12.67)	—	—	0.281
6 wks	222,23	169	2.70 (−1.64 to 7.05)	0	Fixed	0.222
3 mos	222,23	169	0.02 (−5.30 to 5.34)	71	Random	0.994
VAS
Preop	231,33	200	0.13 (−0.45 to 0.70)	14	Fixed	0.665
1 wk	133	63	0.00 (−1.09 to 1.09)	—	—	1.000
2 wks	131	137	0.35 (−0.14 to 0.84)	—	—	0.166
6 wks	131	137	0.17 (−0.30 to 0.64)	—	—	0.482
3 mos	231,33	200	0.05 (−0.28 to 0.39)	27	Fixed	0.758
6 mos	131	137	0.16 (−0.02 to 0.34)	—	—	0.083
KSS-knee score
Preop	122	60	6.00 (−2.18 to 14.18)	—	—	0.151
Discharge	122	60	5.90 (−2.86 to 14.66)	—	—	0.187
Day 17	122	60	0.30 (−8.51 to 9.11)	—	—	0.947
KSS-function score
Preop	122	60	9.20 (1.51 to 16.89)	—	—	0.019*
Discharge	122	60	−0.20 (−7.16 to 6.76)	—	—	0.955
Day 17	122	60	3.20 (−5.98 to 12.38)	—	—	0.495
Knee girth
Preop	324,33,35	268	0.13 (−0.81 to 1.06)	0	Fixed	0.793
Discharge	224,35	205	−0.17 (−1.05 to 0.71)	0	Fixed	0.700
1 wk	133	63	−1.00 (−3.25 to 1.25)	—	—	0.384
3 mos	133	63	0.00 (−1.98 to 1.98)	—	—	1.000
Time up and go
Preop	224,33	204	−1.10 (−3.38 to 1.18)	0	Fixed	0.345
Discharge	124	141	0.10 (−2.16 to 2.36)	—	—	0.931
3 mos	133	63	−1.00 (−3.72 to 1.72)	—	—	0.471

The entries in bold present significant comparisons. *P < 0.05.

Publication bias by Egger's and Begg's tests were not applicable as no more than five studies were included in all of the quantitative pooling.

DISCUSSION

In the past years, although the providing of CPM to patients has been demonstrated to be associated with nonsignificant long-term benefits, and the short-term treatment role of this procedure has also remained controversial, the application of the CPM devices is continued to be a standard of rehabilitation in many institutions. The main purpose for using the CPM devices is to increase the postoperative short-term knee ROM because of that several studies have reported short-term efficacy of CPM on improving the CPM, although most of the studies have shown nonsignificance on the outcome of long-term follow-up.^16,37,38 However, the results of this study has shown that application of CPM in patients operated with TKA for osteoarthritis is of very limited role regarding to the improving of postoperative ROM (flexion, extension, or full ROM), function evaluations (WOMAC score, time up and go, and KSS score), pain symptom, and knee girth, at different follow-up intervals.

Our results contradict many of the previous studies showing improvement on the CPM and clinical outcomes after use of CPM devices.^{12–19,25,37,39} Several systematic reviews favor the application of CPM machines in the first rehabilitation stage with the aim of improving the early ROM.^40–43 In the evidence-based meta-analysis of Brosseau et al.,⁴² they found that when compared with patients treated with PT alone, significant improvements in active knee flexion and analgesic use at 2 wks postoperatively, as well as decreased length of hospital stay and need for knee manipulation, were associated with the use of CPM. In patients with knee operation for anterior cruciate ligament reconstruction, Jaspers et al.⁴³ demonstrated that CPM could significantly improve ROM, pain, and swelling of knee. However, they advocated that more research is necessary to assess the differences in effectiveness with different characteristics of application such as total duration of treatment and intensity of CPM interventions. In the Cochrane systematic review of Milne et al.,⁴⁰ they evaluated the effectiveness of additional CPM on the basis of PT in the short-term rehabilitation after TKA. As a result, CPM combined with PT was found to statistically significantly increase active knee flexion and decrease length of stay and to decrease the need for postoperative manipulation. However, being similar with the results of the current meta-analysis, many other studies have presented adverse opinions, which disfavor the providing of CPM as a standard for patients operated with TKA.^{20–23,44,45} In the study by Boese et al.,⁴⁴ they performed an RCT to investigate the efficacy of three different protocols of CPM (group 1: CPM device on and moving from the immediate postoperative period; group 2: CPM device on and stationary at 90-degree flexion for the first night and then moving throughout the rest of their stay; group 3: no CPM) after TKA. As a result, subjects were followed during the first and second postoperative day until their first follow-up appointment approximately 3–4 wks postoperatively, demonstrating that nonsignificant difference was associated with applying of the two different CPM protocols concerning the outcomes including swelling, drop in hemoglobin, self-reported pain scores, ROM, and hospital length of stay. Dávila Castrodad et al.⁴⁵ conducted a systematic review to evaluate existing postoperative rehabilitation protocols in TKA and concluded that CPM and inpatient rehabilitation may not provide additional benefit to the patient or healthcare system. What is more, the CPM groups were associated with additional costs on the device rental/purchasing and paying for labor of the nursing staff. Joshi et al.²³ performed an RCT to compare the effect of CPM applied after TKA, founding that no significant difference between CPM and non-CPM groups with respect to active ROM, clinical outcomes, and length of hospital stay. Moreover, the additional cost for CPM use, including only device rental and labor, was estimated to be US $235.50 per TKA.

The current meta-analysis, based on high-quality RCT studies, provided a continuous dynamic estimation on a series of outcomes at many available follow-up points, such as discharge, 1 day, 1 wk, 2 wks, 6 wks, 3 mos, and 6 mos. Only slight significant differences were found between the two groups with respect to a few outcomes, including active knee extension at 1 wk and passive knee extension at 1 wk and 3 mos. However, the small amounts of MDs on the extension degrees (all of them were only 3 degrees) indeed were related with limited clinical relevance. The WOMAC score could be used for assess the knee joint function, pain symptom, and stiffness. However, our results found that CPM applying was not related to any additional benefit on the WOMAC subscores at all available time points. The time up and go evaluating the joint mobility and walking ability was also improved by applying of CPM at all follow-ups. Knee girth (ie, midpatellar circumference) is mainly used to reflect the swelling of knee joint. In our results, similar knee girths at discharge, 1 wk, and 3 mos after operation were demonstrated.

The current systematic review and meta-analysis, nevertheless, is of several limitations. Firstly, with the aim of investigating the outcomes at different follow-ups dynamically, a series of subgroup-based meta-analyses were conducted. As a result, only a relatively small number of studies providing primary data were available for pooling. Then, the assessment on the risk of bias showed a generally high risk of bias concerning the allocation concealment (selection bias) and blinding of participants (performance bias). However, this may be inevitable in the situation of applying the CPM devices to the patients.

CONCLUSIONS

Based on the available high-level evidences from RCTs, this study failed to demonstrate a discernable treatment effect of the application of CPM device in patients operated with TKA for osteoarthritis, with respect to the postoperative outcomes including the knee ROM (knee extension, flexion, or full ROM), knee function, knee girth, and pain symptom. Thus, there is at this stage, no indication for CPM procedures in patients operated with TKA as a standard postoperative care.

REFERENCES

1. Pina de MF, Ribeiro AI, Santos C: Epidemiology and variability of orthopaedic procedures worldwide, in: Bentley G (ed): European Instructional Lectures, 11th ed. Germany, Springer Berlin Heidelberg, 2011:9–18

• Cited Here

2. Kurtz S, Ong K, Lau E, et al.: Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am 2007;89:780–5

3. Laubenthal KN, Smidt GL, Kettelkamp DB: A quantitative analysis of knee motion during activities of daily living. Phys Ther 1972;52:34–43

4. Miner AL, Lingard EA, Wright EA, et al.: Knee range of motion after total knee arthroplasty: how important is this as an outcome measure?J Arthroplasty 2003;18:286–94

• Cited Here |
• PubMed

5. Fox JL, Poss R: The role of manipulation following total knee replacement. J Bone Joint Surg Am 1981;63:357–62

6. Salter RB, Simmonds DF, Malcolm BW, et al.: The biological effect of continuous passive motion on the healing of full-thickness defects in articular cartilage. An experimental investigation in the rabbit. J Bone Joint Surg Am 1980;62:1232–51

7. Salter RB, Hamilton HW, Wedge JH, et al.: Clinical application of basic research on continuous passive motion for disorders and injuries of synovial joints: a preliminary report of a feasibility study. J Orthop Res 1984;1:325–42

8. Salter RB: The biologic concept of continuous passive motion of synovial joints. The first 18 years of basic research and its clinical application. Clin Orthop Relat Res 1989;242:12–25

• Cited Here |
• PubMed

9. Salter RB: The physiologic basis of continuous passive motion for articular cartilage healing and regeneration. Hand Clin 1994;10:211–9

10. Coutts RD, Kaita J, Barr R: The role of continuous passive motion in the postoperative rehabilitation of the total knee patient. Orthop Trans 1982;6:277

• Cited Here

11. Salter RB: Continuous passive motion: from origination to research to clinical applications. J Rheumatol 2004;31:2104–5

• Cited Here |
• PubMed

12. Coutts RD, Toth C, Kaita JH: The role of continuous passive motion in the rehabilitation of the total knee patient, in: Hungerford DS, Krackow KA, Kenna RV (eds): Total Knee Arthroplasty: A Comprehensive Approach. Baltimore, Williams & Wilkins, 1984:126–32

• Cited Here

13. Fisher RL, Kloter K, Bzdyra B, et al.: CPM following total knee replacement. Conn Med 1985;49:498–501

• Cited Here

14. Schnebel BE, Evans JP, Flinn D: The use of a passive motion machine. Am J Knee Surg 1989;2:131–6

• Cited Here

15. Denis M, Moffet H, Caron F, et al.: Effectiveness of continuous passive motion and conventional physical therapy after total knee arthroplasty: a randomized clinical trial. Phys Ther 2006;86:174–85

16. Bennett LA, Brearley SC, Hart JA, et al.: A comparison of 2 continuous passive motion protocols after total knee arthroplasty: a controlled and randomized study. J Arthroplasty 2005;20:225–33

17. Viswanathan P, Kidd M: Effect of continuous passive motion following total knee arthroplasty on knee range of motion and function: a systematic review. NZ J Physiother 2010;38:14–22

• Cited Here

18. Liao CD, Huang YC, Lin LF, et al.: Continuous passive motion and its effects on knee flexion after total knee arthroplasty in patients with knee osteoarthritis. Knee Surg Sports Traumatol Arthrosc 2016;24:2578–86

19. MacDonald SJ, Bourne RB, Rorabeck CH, et al.: Prospective randomized clinical trial of continuous passive motion after total knee arthroplasty. Clin Orthop Relat Res 2000;380:30–5

20. Nadler SF, Malanga GA, Zimmerman JR: Continuous passive motion in the rehabilitation setting: a retrospective study. Am J Phys Med Rehabil 1993;72:162–5

• Cited Here |
• PubMed

21. Leach W, Reid J, Murphy F: Continuous passive motion following total knee replacement: a prospective randomized trial with follow-up to 1 year. Knee Surg Sports Traumatol Arthrosc 2006;14:922–6

22. Lenssen TA, van Steyn MJ, Crijns YH, et al.: Effectiveness of prolonged use of continuous passive motion (CPM), as an adjunct to physiotherapy, after total knee arthroplasty. BMC Musculoskelet Disord 2008;29:9–60

• Cited Here

23. Joshi RN, White PB, Murray-Weir M, et al.: Prospective randomized trial of the efficacy of continuous passive motion post total knee arthroplasty: experience of the hospital for special surgery. J Arthroplasty 2015;30:2364–9

24. Herbold JA, Bonistall K, Blackburn M, et al.: A randomized controlled trial of the effectiveness of continuous passive motion following total knee replacement. Arch Phys Med Rehabil 2014;95:1240–5

25. Johnson DP: The effect of continuous passive motion on wound-healing and joint mobility after knee arthroplasty. J Bone Joint Surg Am 1990;72A:421–6

26. Vince KG, Kelly MA, Beck J, et al.: Continuous passive motion after total knee arthroplasty. J Arthroplasty 1987;2:281–4

27. Gose JC: Continuous passive motion in the postoperative treatment of patients with total knee replacement: a retrospective study. Phys Ther 1987;67:39–42

• Cited Here |
• PubMed

28. Moher D, Liberati A, Tetzlaff J, et al.: Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ 2009;339:b2535

29. Higgins JP, Thompson SG, Deeks JJ, et al.: Measuring inconsistency in meta-analyses. BMJ 2003;327:557–60

30. Egger M, Davey Smith G, Schneider M, et al.: Bias in meta-analysis detected by a simple, graphical test. BMJ 1997;315:629–34

31. Chen LH, Chen CH, Lin SY, et al.: Aggressive continuous passive motion exercise does not improve knee range of motion after total knee arthroplasty. J Clin Nurs 2013;22:389–94

32. Alkire MR, Swank ML: Use of inpatient continuous passive motion versus no CPM in computer-assisted total knee arthroplasty. Orthop Nurs 2010;29:36–40

33. Bruun-Olsen V, Heiberg KE, Mengshoel AM: Continuous passive motion as an adjunct to active exercises in early rehabilitation following total knee arthroplasty – a randomized controlled trial. Disabil Rehabil 2009;31:277–83

34. Baloch N, Zubairi AJ, Rashid RH, et al.: Effect of continuous passive motion on knee flexion range of motion after total knee arthroplasty. J Pak Med Assoc 2015;65:S32–4

• Cited Here

35. Chen B, Zimmerman JR, Soulen L, et al.: Continuous passive motion after total knee arthroplasty: a prospective study. Am J Phys Med Rehabil 2000;79:421–6

• Cited Here |
• PubMed

36. Wirries N, Ezechieli M, Stimpel K, et al.: Impact of continuous passive motion on rehabilitation following total knee arthroplasty. Physiother Res Int 2020;25:e1869

• Cited Here

37. Johnson DP, Eastwood DM: Beneficial effects of continuous passive motion after total condylar knee arthroplasty. Ann R Coll Surg Engl 1992;74:412–6

• Cited Here |
• PubMed

38. Jordan LR, Siegel JL, Olivo JL, et al.: Early flexion routine. An alternative method of continuous passive motion. Clin Orthop Relat Res 1995;315:231–3

• Cited Here |
• PubMed

39. Romness DW, Rand JA: The role of continuous passive motion following total knee arthroplasty. Clin Orthop Relat Res 1988;226:34–7

40. Milne S, Brosseau L, Robinson V, et al.: Continuous passive motion following total knee arthroplasty. Cochrane Database Syst Rev 2003;CD004260

• Cited Here |
• PubMed

41. Lenssen AF, Koke AJA, Bie de RA, et al.: Continuous passive motion in rehabilitation following total knee arthroplasty; short and long term effects on range of motion. Phys Ther Rev 2003;8:113–21

• Cited Here

42. Brosseau L, Milne S, Wells G, et al.: Efficacy of continuous passive motion following total knee arthroplasty: a meta-analysis. J Rheumatol 2004;31:2251–64

• Cited Here

43. Jaspers T, Taeymans J, Hirschmüller A, et al.: Continuous passive motion does improve range of motion, pain and swelling after ACL reconstruction: a systematic review and meta-analysis. Z Orthop Unfall 2019;157:279–91

• Cited Here

44. Boese CK, Weis M, Phillips T, et al.: The efficacy of continuous passive motion after total knee arthroplasty: a comparison of three protocols. J Arthroplasty 2014;29:1158–62

45. Dávila Castrodad IM, Recai TM, Abraham MM, et al.: Rehabilitation protocols following total knee arthroplasty: a review of study designs and outcome measures. Ann Transl Med 2019;7:S255

• Cited Here |
• PubMed

Keywords:

Total Knee Arthroplasty; Continuous Passive Motion; Knee Osteoarthritis; Meta-analysis

Supplemental Digital Content

Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.

lewiswarts1960.blogspot.com

Source: https://journals.lww.com/ajpmr/Fulltext/2021/12000/The_Effect_of_Continuous_Passive_Motion_in.8.aspx

Share this post