A comparison of 2 cpm protocols after total knee arthroplasty
The Journal of Arthroplasty Vol. 20 No. 2 2005 A Comparison of 2 Continuous Passive Motion Protocols After Total Knee Arthroplasty A Controlled and Randomized Study Lisa A. Bennett, BAppSc, MPhty,* Sara C. Brearley, BAppSc,y John A. L. Hart, MBBS, FRACS, FA, Orth A, FASMF, FACSP,z and Michael J. Bailey, BSc, MSc§ Abstract: Effect of continuous passive motion (CPM) protocols on outcomes after total knee arthroplasty. In this prospective randomized controlled study, 147 patients were assigned to 1 of 3 treatment groups: CPM from 08 to 408 and increased by 108 per day, CPM from 908 to 508 (early flexion) and gradually progressed into full extension over a 3-day period, and a no-CPM group. The CPM was administered twice a day for 3 hours over a 5-day period. All patients participated in the same postoperative physiotherapy program. Patients were assessed preoperatively, day 5, 3 months, and 1 year postoperatively. The early flexion group had significantly more range of flexion than both the standard and control groups at day 5. There was no significant difference between the groups for any other variable tested at any time frame. Key words: total knee arthroplasty, CPM, rehabilitation, outcomes. n 2005 Elsevier Inc. All rights reserved.Continuous passive motion (CPM) can be applied to tion was detrimental to joints, motion was benefi-the knee joint by a mechanical device that moves cial, and CPM minimized forces across damagedthrough a preset range of motion (ROM) at a joint surfaces. For motion to be continuous, it has toselected velocity. Salter [1-3] researched and devel- be applied passively, as muscles would fatigue withoped the concept of CPM after experiments in rabbits continuous active movement of a joint [1-3].where he demonstrated that articular cartilage Continuous passive motion devices have beendefects and intra-articular fractures healed better widely used as an adjunct to physiotherapy afterwhen CPM was used. He believed that immobiliza- total knee arthroplasty (TKA) for the past 2 decades ; however, there is controversy as to whether it is useful. Numerous studies have been From the *Department of Physiotherapy, The Alfred, Melbourne, carried out on the effects of CPM after TKA.Australia; yDepartment of Physiotherapy, Caulfield General Medical Parameters such as knee ROM, length of stayCentre, Melbourne, Australia; zDepartment of Surgery, The Alfred,Monash University, Melbourne, Australia, and §Department of (LOS), wound healing, and knee function haveEpidemiology and Preventative Medicine, Monash University, Australia. been evaluated with contradictory results. Some Submitted October 27, 2003; accepted August 9, 2004. [4-12] recommend CPM, whereas others [13-18] Benefits or funds were received in partial or total support ofthe research material described in this article from the Alfred, have found it to be of little value in rehabilitation ofMelbourne, Australia (small projects grant). the knee after TKA. The differences in outcomes can Reprint requests: (From 15 October 2004 to 15 October 2005) be explained partly by variations in study design andSara C Brearley, Physiotherapy Rehabilitation Department,Caulfield 3162, Victoria, Australia. (From 16 October 2005) Lisa methodology. Differences in the duration of appli-Bennett, Physiotherapy Department, The Alfred, Commercial cation of CPM ranging from as little as 4 hours a dayRoad, Prahran 3182, Australia.  to almost 24 hours per day  have been n 2005 Elsevier Inc. All rights reserved. 0883-5403/04/2002-0013$30.00/0 reported. Some studies [13,15,19-21] have included doi:10.1016/j.arth.2004.08.009 small samples, which may affect validity. 225
226 The Journal of Arthroplasty Vol. 20 No. 2 February 2005 The primary motions of the knee joint are flexion flexion and 08 extension of the knee, decreasingand extension . Traditionally, CPM has been LOS, and improving knee function.administered by moving the knee from full exten- 2. There would be no difference in wound healingsion through increasing degrees of flexion . For between the 3 groups.the purposes of this paper, we refer to this method asstandard CPM. More recently, an early flexion Materials and Methodsregime has been advocated in which the knee isprogressively moved from flexion to extension Study Design[21,23-25]. Jordan et al  conducted a non-randomized trial comparing standard and early Patients were allocated by a block randomizationflexion CPM after primary TKA. Early flexion procedure into 1 of 3 groups:resulted in decreased LOS, decreased hospital costs,and increased ROM at 1 year. On the other hand, ! Group A: Standard CPM regimeMacDonald et al  found no statistical differences, ! Group B: Early flexion CPM regimeat any measured interval, between standard and ! Group C: No CPM (the control group).early flexion CPM regimes and a no-CPM group. The operating surgeon and the independentTheir randomized trial evaluated cumulative anal- assessor were blinded to the group allocation of thegesic requirements, ROM, LOS, and Knee Society subjects, and the subjects were blinded to the studyscores. The authors acknowledge, however, that a hypotheses. To determine the number of subjectslonger trial of CPM may have benefited these required to achieve statistical significance, a powerpatients as CPM was only utilized for a maximum analysis was performed. The sample size was basedof 24 hours postoperatively. Our study is the first on 3 pairwise comparisons of the groups each at aprospective randomized controlled trial comparing 2 significance level of 1.7% (=5%/3) at 5 days afterCPM protocols where the CPM has been adminis- operation. To detect a difference of 78 knee ROMtered over a significant period of time. between groups with an SD of 108 within each group, the study needed to recruit 43 subjects per Aims of The Study group to achieve 80% power. It is generally accepted that goniometric measurements of the knee have an The aims of the research were to assess error rate of F58 . If a 78 ROM difference existed in our study, this would represent a true difference1. The effect of CPM after TKA on knee ROM, between the groups A, B, and C rather than a length of hospital stay, wound healing, knee difference due to measurement error. function, and perceived health status.2. Whether early flexion CPM produces a better Study Cohort outcome than a standard CPM regime or control with no CPM. One hundred forty-eight patients were initially recruited into the study. One patient was subse-Hypotheses quently excluded from the study, as we were unable to achieve 908 knee flexion on the CPM1. Early flexion CPM would be more effective than device in recovery. Results were analyzed for the standard CPM and no CPM in achieving 908 remaining 147 patients. They were admitted to The Table 1. Demographic Information A B CGroup (Standard CPM) (Early flexion CPM) (No CPM) TotalPatients (N) 47 48 52 147Gender (% female) 72.3 64.6 67.3Mean age (y) 70.7 71.4 71.7Genesis I prosthesis (N) 7 5 7 19Genesis II prosthesis (N) 40 43 45 128Cruciate retained (N) 43 41 46 130Posterior stabilized (N) 4 7 6 17Patella resurfaced (N) 22 24 28 74Patella not resurfaced (N) 25 24 24 73
Continuous Passive Motion Protocols After Total Knee Arthroplasty ! Bennett et al 227 Table 2. Physiotherapy Program prostheses were again used at the discretion of the operating surgeon (Table 1). The patella was notCommencing day 1 postoperativelyAnkle dorsi flexion/plantar flexion routinely resurfaced, at the discretion of the treat-Static quadriceps progressing to quadriceps over a fulcrum ing surgeon (Table 1). (active-assisted to active) Two Redivac drains were inserted and laterStatic glutealsGentle active/active-assisted hip knee flexion on a removed at 48 hours. An attempt was made to powder board standardize the anesthetic protocol, but because ofChest care as indicated individual patient requirements this was notOn day 2 possible. There was no significant difference be-Exercises as above progressing to independent straight leg raise tween the groups A, B, and C according toTransfer out of bed and sit out of bed in a chair if tolerated anesthetic techniques.On day 3Exercises as above Physiotherapy ProgramKnee flexion over the side of the bedAmbulation with gait aids, full weight bearing initiated All patients participated in a standardized phys- iotherapy program (Table 2).Day 4 onwardKnee flexion and extension ROM and strength, gait reeducation, and steps practiced. Patients with a quadriceps lag greater than 108 ambulated with CPM Protocols EKS until adequate knee control obtainedProgram conducted half an hour twice a day Group A: Standard except on weekends when patients were seen once a day Day 1 (operative day): CPM machine applied in the recovery room set at 08 to 408 for 3 hours. The CPM was removed and extension knee splint (EKS) ap-Alfred, Melbourne, between January 1997 and July plied to maintain the knee in extension overnight.2000 for surgery using a Genesis I or II prosthesis Day 2: CPM machine applied early in the(Smith and Nephew, Memphis, Tenn). All had a morning at 08 to 458 for 3 hours and reapplied lateprimary diagnosis of osteoarthritis. Those excluded afternoon at 08 to 508 for 3 hours. Extension kneehad bilateral TKA performed at the same time, splint applied overnight.revision of TKA, rheumatoid arthritis, or hemophil- Days 3 to 6: CPM increased 58 twice a day untilia. Demographic information is described in Table 1. ceased on day 6. Extension knee splint applied overnight.Surgical Procedure Group B: Early Flexion Initially, Genesis I TKA prostheses were usedexclusively in the study, but this protocol changed Day 1 (operative day): CPM machine was appliedto Genesis II when the prosthesis became available. in the recovery room at 908 to 508 knee flexion.Ten experienced surgeons working in 2 surgical The CPM machine was cycled between 908 and 508units at The Alfred performed the operations. flexion for 3 hours. Knee rested at 908 flexion onTrainee registrars supervised by the senior surgeons the machine overnight.performed some procedures. An anteromedial or Day 2: CPM between 908 and 408 for 3 hours.midline incision was used, and the knees were Continuous passive motion was turned off butapproached through a medial parapatellar capsular remained in situ with the knee resting in 908 flexionincision. Cruciate retaining and posterior-stabilized on the machine. Continuous passive motion applied Table 3. Mean Knee FlexionCPM Group A (Standard) B (Early Flexion) C (None)Knee ROM Active Flexion Passive Flexion Active Flexion Passive Flexion Active Flexion Passive FlexionTimePreoperative 102.58 108.38 102.58 108.68 102.68 108.88Day 5 69.48 75.38 78.78 86.68 64.98 71.283 mo 95.08 95.88 93.781y 102.78 102.58 102.98
228 The Journal of Arthroplasty Vol. 20 No. 2 February 2005 Table 4. Mean Passive Knee Extension (Fixed Flexion Deformity) and Quadriceps LagCPM Group A (Standard) B (Early Flexion ) C (None)Knee ROM Quadriceps Lag Passive Extension Quadriceps Lag Passive Extension Quadriceps Lag Passive ExtensionTimePreoperative 2.08 9.38 2.28 9.78 1.88 10.08Day 5 12.18 6.28 11.68 7.78 12.98 6.583 mo 2.38 7.28 3.28 8.78 1.68 6.481y 1.08 3.68 1.58 3.48 0.18 4.18late afternoon at 908 and 308 flexion for 3 hours, Analgesic requirements were not controlled inand the knee was rested in 908 flexion overnight. this study. If one patient group experienced Day 3: CPM between 908 and 208 for 3 hours in significantly more pain than the others, this couldthe morning and between 908 and 108 for 3 hours influence postoperative recovery and, hence, havein the afternoon. The CPM was then removed and an impact on the results. However, a specializedEKS applied overnight. pain team monitored these patients postoperative- Day 4: CPM between 908 and 08 for 3 hours in ly, and pain levels were recorded using a visualthe morning and afternoon. The CPM was removed analogue scale twice a day when the machine wasand the EKS applied overnight. not cycling, for the first five postoperative days. Days 5 to 6: CPM between 908 and 08 for 3 hoursin the morning and afternoon. Extension knee Data Analysissplint in bed at night. Continuous passive motionceased at the end of day 6. Means and standard errors were computed for each group at each time point (baseline, 5 days, 3Group C: No CPM months, 1 year). Univariate analysis was conducted EKS in theater and remained in situ when in bed using v 2 tests for categorical variables and analysis ofovernight and removed during the day. The patient variance for continuous normally distributed data.received no CPM. Where data were found to be log-normally distrib- uted (LOS, passive extension, and quadriceps lag), a log transformation was performed before analysis. Measurements Multivariate analysis was conducted using a repeat measures analysis of covariance adjusting for base- Data were collected from each patient in the line prognostic factors. Wound healing and perio-preoperative period (at a preadmission clinic) and perative anesthetic requirements were evaluatedpostoperatively at 3 months and 1 year. using v 2 tests for equal proportion. Perceived health1. Knee flexion, extension, and quadriceps lag status, measured on an ordinal scale, was evaluated were measured in degrees with a standard using nonparametric analysis. universal goniometer . These measurements were also taken on the fifth postoperative day. Results2. Knee function was assessed using the functional component of the Knee Society Clinical Rating Range of Motion System .3. Perceived health status of each patient was Preoperatively, there were no statistically signif- assessed using the Short-Form 12-Item Health icant differences between the 3 groups in mean Survey (SF-12) . On the fifth postoperative day, wound healing wasevaluated using the following classification system: Table 5. Length of Hospital Stay (Acute) in Daysaseptic wound discharge, aseptic wound dehiscence, Group N Geometric Mean LOSsuperficial infection, or deep infection . Woundhealing was considered to have failed if there was A (Standard CPM) 47 8.8infection or aseptic dehiscence of the wound. B (Early flexion CPM) 48 8.1 C (No CPM) 52 8 Hospital (inpatient) LOS was recorded in days in P .51the acute and rehabilitation settings.
Continuous Passive Motion Protocols After Total Knee Arthroplasty ! Bennett et al 229 Table 6. Length of Hospital Stay (Rehabilitation) Table 8. Wound Healing in Days Wound HealingGroup N Geometric Mean LOS (5th Postoperative Day) Yes (N) No (N)A (Standard CPM) 32 18.7 A (Standard CPM) 93.5% 43 6.5% 3B (Early flexion CPM) 29 17.8 B (Early flexion CPM) 98% 47 2% 1C (No CPM) 39 15.8 C (No CPM) 92.3% 48 7.7% 4P .58 P .44passive or active flexion (Table 3), or in quadri- Painceps lag or passive extension (Table 4). At day5 postoperatively, there were significant differ- The mean of the 10 visual analogue scale scoresences between the groups in active flexion for each patient was calculated; hence, a score out( P = .008 and P b .0001) and passive flexion of 10 was determined. There are statistically( P = .007 and P b .0001) (Table 3). At 3 months significant differences in mean pain scores betweenand 1 year postoperatively, there were no signif- groups A and B ( P b .0001), groups B and C ( P =icant differences between the groups in active .005), and groups A and C ( P = .013) (see Table 7).flexion, passive extension, and quadriceps lag. These differences are, however, not clinically(Tables 3 and 4). significant as they represent less than or equal to 1 point on a 10-point scale.Length of Stay Wound Healing Patients were discharged home when the mul-tidisciplinary team assessed them as being able to Healing rates for the groups are represented inmanage safely in their home environment. Some Table 8. A v 2 analysis revealed that there was nopatients were transferred to a rehabilitation significant difference between the groups in woundfacility for ongoing therapy before discharge. healing rates ( P = .44).Length of acute hospital stay (in days) for the3 groups was 8.8 for group A, 8.1 for group B, Knee Functionand 8.0 for group C. There was no significant Knee function was assessed using the Kneedifference between the groups ( P = .51) (Table 5). Society Clinical Rating System . There wasOne hundred patients went to a rehabilitation no significant difference between the 3 groupsfacility. Of these, 32 were in group A (geometric preoperatively, at 3 months or at 1 year (Table 9).mean LOS = 18.7 days), 29 were in group B(geometric mean LOS =17.8 days), and 39 were in Perceived Health Status Measure SF-12group C (geometric mean LOS =15.8 days). Therewas no significant difference between the groups The SF-12 is a shorter version of the SF-36( P = .58) (Table 6). used to reproduce its Physical Component Sum- mary (PCS) and Mental Component Summary (MCS) scores . There was no significant difference between the groups in PCS and MCS preoperatively, nor at 3 months and 1 year postoperatively. Table 7. Visual Analogue Scale Scores Mean Score OverGroup Day 1 Day 2 Day 3 Day 4 Day 5 5 days Table 9. Knee Society Scores: FunctionA (Standard 4.1 3.7 3.5 3.4 3.2 3.6 (Means and SEs) CPM)B (Early 3.2 2.9 2.5 2.3 2.4 2.6 CPM group A B C flexion CPM) Preoperative 40.1 (3.0) 42.1 (3.0) 45.3 (2.8)C (No CPM) 3.5 3.1 3.1 3.1 2.9 3.1 3 mo 51.9 (3.6) 52.2 (3.2) 56.0 (3.0)P b.0001 1y 57.9 (3.6) 59.6 (3.4) 58.1 (3.1)
230 The Journal of Arthroplasty Vol. 20 No. 2 February 2005 Discussion In contrast, Harms and Engstrom  found that CPM resulted in a significant improvement in kneeFlexion: Early Postoperative Phase extension. In our study, we found no significant differences between the groups in passive knee The present study demonstrated a significant extension at 3 months nor at 1 year. Other authorsimprovement in active and passive knee flexion have reported the same finding [10,19,24,25].at day 5 postoperatively in group B compared togroups A and C. McInnes et al  reported that Quadriceps Lagstandard CPM significantly increased active flexionat 1 week postoperatively but not at 6 weeks. We found no significant differences between theHarms and Engstrom  found knee flexion was groups in quadriceps lag at day 5, 3 months, and 1increased in a standard CPM group when compared year postoperatively. Other authors [23-25] did notwith a no-CPM group. Yashar et al  found a examine quadriceps lag in their publications. Ngsignificant difference in passive knee flexion in and Yeo  found no significant differencesfavor of an early flexion group. Other studies have between groups in active extension on the fifthreported no significant differences [19-21]. postoperative day.Flexion: Late Postoperative Phase Length of Stay At 3 months and 1 year postoperatively, there There were no significant differences betweenwas no significant difference between the groups in the groups in acute or rehabilitation hospitalactive or passive knee flexion in our study. This is inpatient LOS, which is in agreement with Yasharin agreement with the findings of other studies at et al  and MacDonald et al , but is in3-, 6-, and 12-month evaluations [17,19,24,25]. In contrast to the findings of the nonrandomizedcontrast, Jordan et al  in a nonrandomized study on 100 TKA patients by Jordan et al .study reported that an early flexion CPM regime The latter authors reported that the early flexionproduced increased flexion ROM at 1 year com- resulted in decreased LOS and decreased hospitalpared with standard CPM. costs and improved ROM at 1 year. Our acute The average active range of knee flexion in our hospital LOS for all groups was higher than thatstudy, at 1 year postoperatively, was 1038 for all reported by MacDonald et al . There are agroups. This value is lower than the 1128 average number of possible reasons for this includingknee flexion reported by MacDonald et al  and patient demographics. MacDonald et al  ex-Yashar et al . The likely explanation for this cluded patients older than 80 years and those whodifference is that postoperative ROM is influenced were unable to ambulate 30 m and climb 10 steps.by preoperative ROM . In our study, the patients In our study, age was not an exclusion criterionwere all public hospital patients and mean preoper- and some of our patients were virtually wheelchairative active flexion was 102.68 (Table 3). In a cohort bound before surgery because of a long waiting list.treated privately, the average preoperative flexion These are important factors in outcome. Further-was 111.58 and the postoperative flexion was 111.68. more, MacDonald et al  excluded patients ifMacDonald et al  reported a mean preoperative they had fixed flexion deformities greater than 158,range of 1068, whereas Yashar et al  reported a whereas in our study 17 patients had deformities ofmean preoperative ROM of 1108. The mean age of that magnitude. Thus, over 10% of our subjectspatients in our study was 71 years. In the study of had severe degenerate disease of the knee preop-MacDonald et al , the mean age was not stated, eratively, which would have contributed to abut patients older than 80 years were excluded, as slower recovery. Johnson [7,8] found LOS waswere those with a greater than 158 fixed flexion significantly reduced after the use of standard CPMdeformity. In the study of Yashar et al , the mean compared with control. However, others [4,9] haveage was 69 years. In our study, increased patient age found no significant difference in LOS betweenand stiffer knees preoperatively may have contrib- standard and control groups. Local discharge poli-uted to the reduced range of movement. cies and the availability of rehabilitation facilities also affect length of acute hospital stay.Extension Wound Healing We found no statistically significant differencesbetween the groups in passive extension in the first Johnson  reported that transcutaneous oxy-postoperative week, as did previous authors [9,21]. gen tension on the lateral aspect of the incision
Continuous Passive Motion Protocols After Total Knee Arthroplasty ! Bennett et al 231decreased as the knee flexed past 408; hence, we preoperatively (Table 10). The reason for this is notwere somewhat concerned about the risk of wound clear. The number of complications in the no-CPMbreakdown in the early flexion group. In the group was not significantly different when com-present study, the early flexion group knees were pared to the CPM groups at 3 months and 1 year.maintained in 908 flexion overnight for 2 nights, Adequate test-retest reliability using the SF-12 wasbut there were no significant differences between demonstrated by Ware et al : PCS = 0.89 andthe groups in wound healing when assessed on the MCS = 0.76. This measurement tool was designedfifth postoperative day, which agrees with Yashar et for large group studies with patient populationsal . Our early flexion group had fewer wound greater than 500 . Therefore, it may not be thecomplications than the control or standard groups most reliable tool to estimate perceived health(Table 8). Ververeli et al  also found that there status in clinical applications such as the presentwas no significant difference in wound healing study.between standard and no-CPM groups. Study Limitations and SuggestionsKnee Function for Future Research The functional component of the Knee Society Our patients attended a preadmission clinicClinical Rating System  was used as a mea- where they received education, written informa-surement tool in this study. It demonstrates good tion about TKA, and a personalized exerciseresponsiveness when used to assess outcome after program to be commenced before their operation.TKA . Despite a 5-point difference in preoper- Attendance at this clinic may have influenced theative Knee Society function scores between control results in favor of the no-CPM group. Postopera-and standard CPM groups (Table 9), there were no tively patients were given 2 half-hour sessions ofstatistically significant group differences preopera- physiotherapy daily during the week and 1 half-tively. In addition, there were no statistically hour session on weekends. This intensive programsignificant differences at 3 months or 1 year is not readily available in all hospitals. The role ofbetween control and CPM treatment groups. Sim- CPM in the early postoperative management ofilarly, MacDonald et al  also found that there patients who are medically or psychologicallywere no differences between the control and CPM impaired was not addressed in our study and maygroups preoperatively and at 1 year when evaluat- require further investigation. Colwell anded using the Knee Society scoring system. McInnes Morris  found that isolating outliers made theet al  reported no significant differences between LOS significantly different between a no-CPMstandard CPM and control groups in knee function group and a standard CPM group.at 6 weeks after TKA. Statistical tests are for means and assess whether the means of different groups are statisticallyPerceived Health Status different. This conclusion fails to identify individ- uals or subgroups that may have benefited from the The Medical Outcomes Study SF-12 includes 12 intervention. Thirty-three of the 147 patientsquestions from the SF-36. No other authors evaluated in this study had a preexisting fixedevaluating the effects of CPM on TKA have used flexion deformity (FFD) of 158 or more. Wethe SF-12. In the present study, we found no dif- analyzed the day 5 postoperative results of theseferences in SF-12 scores preoperatively, at 3 patients for the purpose of generating ideas formonths or at 1 year between the 3 groups. How- future research. Statistical analysis of this subgroupever, the PCS for the control group was signifi- showed that these patients had statistically signif-cantly worse at 1 year postoperatively compared to icant increases in quadriceps lag ( P = .0005) and Table 10. SF-12 Scores (Means and SEs)Group A (Standard CPM) B (Early Flexion CPM) C (No CPM)SF-12 PCS MCS PCS MCS PC MCSPreoperative 38.0 (2.0) 48.1 (1.8) 42.2 (2.0) 45.7 (1.8) 43.4 (1.8) 44.5 (1.7)3 mo 39.4 (2.3) 50.4 (2.1) 38.4 (2.1) 53.3 (1.9) 39.5 (1.9) 54.1 (1.8)1y 43.8 (2.4) 54.3 (2.2) 40.0 (2.3) 54.4 (2.1) 37.8 (2.1) 54.3 (1.9)
232 The Journal of Arthroplasty Vol. 20 No. 2 February 2005passive extension loss ( P b .0001) when compared an experimental investigation in the rabbit. J Boneto the rest of the group (patients with a FFD V108). Joint Surg 1980;62A:1232.We also analyzed the FFD subgroup according to 3. Salter RB: Motion vs rest: why immobilize joints? JCPM group allocation (A, B, C). There were no Bone Joint Surg 1982;64B:251. 4. Harms M, Engstrom B. Continuous passive motion asstatistically significant differences in quadriceps lag an adjunct to treatment in the physiotherapy man-or passive extension loss between the groups. agement of the total knee arthroplasty patient.Unfortunately, the sample size was small and a Physiotherapy 1991;77:301.larger sample of patients with clinically significant 5. Coutts RD, Toth C, Kaita JH. The role of continuouspreexisting FFD would need to be evaluated to passive motion in the rehabilitation of the total kneedetermine whether CPM makes a difference for patient. In Hungerford DS, Krackow K, Kenna RV,some patients after TKA. editors. Total knee arthroplasty: a comprehensive approach (p. 126). Baltimore: Williams & Wilkins; 1984. Conclusion 6. Coutts RD. Continuous passive motion in the reha- bilitation of the total knee patient: its role and effect. The results of this study show that an early Orthop Rev 1986;15:27.flexion CPM regime is useful in achieving a better 7. Johnson DP. The effect of continuous passive motionrange of active and passive flexion in the early on wound healing and joint mobility after kneepostoperative period after TKA, but did not result in arthroplasty. J Bone Joint Surg 1990;72A:421.decreased LOS. Length of stay is, however, multi- 8. Johnson DP, Eastwood DM. Beneficial effects offactorial and influenced by social issues in addition continuous passive motion after total condylar knee arthroplasty. Ann R Coll Surg Engl 1992;74:412.to joint function. We were unable to demonstrate 9. McInnes J, Larson MG, Daltroy LH, et al. A controlledany significant difference between standard and evaluation of continuous passive motion in patientsearly flexion CPM and control groups after dis- undergoing total knee arthroplasty. JAMA 1992;charge. There was no difference in wound healing 268:1423.rates, functional outcome, or perceived health 10. Maloney WJ, Schurman DJ, Hangen D, et al. Thestatus. From these results, we have been unable influence of continuous passive motion on outcometo justify the use of CPM as a routine rehabilitation in total knee arthroplasty. Clin Orthop 1990;256:162.tool in the public hospital setting after TKA. The 11. Romness DW, Rand JA. The role of continuousrole of CPM in the management of patients with passive motion following total knee arthroplasty.difficult problems or in facilities where manpower Clin Orthop 1988;226:34.is limited warrants further study. 12. Ververeli PA, Sutton DC, Hearn SL, et al. Continuous passive motion after total knee arthroplasty — analysis of costs and benefits. Clin Orthop 1995; 321:208. Acknowledgments 13. Chiarello CM, Gundersen MS, O’Halloran T. The effect of continuous passive motion duration and This research was supported by an Alfred increment on range of motion in total knee arthro-Hospital small project grant. The authors wish to plasty patients. J Orthop Sports Phys Ther 1997;acknowledge Helen Donaldson of Smith and 25:119.Nephew Surgical Pty Ltd for her extensive role in 14. Kumar PJ, McPherson EJ, Dorr LD, et al. Rehabili-data collection. We would also like to thank Lara tation after total knee arthroplasty — a comparison ofKimmel and members of the physiotherapy de- 2 rehabilitation techniques. Clin Orthop 1996; 331:93.partment at The Alfred for treating the patients, 15. Nielson PT, Rechnagel K, Nielsen SE. No effect ofand the surgeons of the Department of Orthopedic continuous passive motion after arthroplasty of theSurgery for allowing their patients to participate in knee. Acta Orthop Scand 1988;59:580.the study. 16. Pope RO, Corcoran S, McCaul K, et al. Continuous passive motion after primary total knee arthro- plasty — does it offer any benefits? J Bone Joint Surg References Br 1997;79B:914. 17. Ritter MA, Gandolf VS, Holston KS. Continuous1. Salter RB, Field P. The effects of continuous com- passive motion versus physical therapy in total knee pression on living articular cartilage: an experimental arthroplasty. Clin Orthop 1989;244:239. investigation. J Bone Joint Surg 1960;42A:31. 18. Nadler SF, Malanga GA, Zimmerman JR. Continuous2. Salter RB, Simmonds DF, Malcolm BW, et al. The passive motion in the rehabilitation setting. A biological effect of continuous passive motion on the retrospective study. Am J Phys Med Rehabil 1993; healing of full-thickness defects in articular cartilage: 72:162.
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