Changes in pain and physical function during waiting time and 3 months after knee joint arthroplasty

Abstract

To determine changes in physical and social function during a prolonged preoperative waiting period and at 3 months after total knee arthroplasty.
Forty-three patients were evaluated on the day that surgery was decided, the day before surgery, and 3 months afterwards.
Knee pain and function were assessed using a visual analogue scale and a functional assessment system. Isometric knee flexion extension strength and mobility were measured.
Knee pain and muscle strength remained unchanged during the mean waiting time of 10 (standard deviation 8) months. On the affected side, knee extension strength was 19% weaker than on the contralateral side and did not change pre-operatively. Post-operatively, knee pain decreased by 50%. Knee extension strength decreased by 26% and flexion strength by 12% compared with the initial assessments. Knee extension strength of the operated side was 42% lower than on the non-operated side. Knee flexion mobility was decreased by 8%, while the initially detected knee extension deficit of 10 degrees (SD 7) remained unchanged. The functional assessment system did not detect any changes in function.
Waiting time did not affect knee pain or isometric knee extension/flexion strength. Three months post-operatively, knee pain had decreased significantly, but the strength of the operated knee was significantly lower than the pre-operative level.

Full text

J Rehabil Med 46
ORIGINAL REPORT
J Rehabil Med 2014; 46: 166–172
© 2014 The Authors. doi: 10.2340/16501977-1242
Journal Compilation © 2014 Foundation of Rehabilitation Information. ISSN 1650-1977
Objective: To evaluate the efcacy of a delayed home exercise
programme compared with normal care after primary total
knee arthroplasty.
Design: Single-blind, prospective, randomized, controlled trial.
Participants: A total of 108 participants (61% females, mean
age 69 years [standard deviation 8.7]), were randomized to a
home-based exercise group (EG, n = 53) or to a control group
(CG, n = 55).
Methods: Two months post-operatively, the EG received a
home exercise programme, while the CG received no addi-
tional guidance. The outcome measurements were: pain and
disability, measured using the Western Ontario and McMas-
ter Universities Osteoarthritis Index (WOMAC); health-
related quality of life (HRQoL), measured using the Short
Form-36 questionnaire (SF-36); maximal walking speed;
isometric knee muscle strength; and the Timed Up and Go
(TUG) test. Measurements were made at baseline and at 12
months thereafter.
Results: At the 12-month follow-up, maximal walking speed
(p < 0.001) and knee exion strength (p = 0.009) were signi-
cantly greater in the EG. Both groups showed similar im-
provements in all of the WOMAC subscale scores, the SF-36
summary scores and the TUG time.
Conclusion: Home-based training was not superior to nor-
mal care with regard to pain, disability or HRQoL, but
resulted in greater improvement in objectively measured
physical performance.
Key words: osteoarthritis; knee replacement; exercise; disability;
health-related quality of life; rehabilitation; home programme.
J Rehabil Med 2014; 46: 166–172
Correspondence address: Jari Ylinen, Department of Physical
Medicine and Rehabilitation, Central Finland Health Care
District, Keskussairaalantie 19, FI-40620 Jyväskylä, Finland.
E-mail: jari.ylinen@ksshp.
Accepted Aug 20, 2013; Epub ahead of print Nov 12, 2013
INTRODUCTION
The number of joint replacement procedures worldwide has
increased considerably in recent years (1, 2). In Finland, there
has been a 69% increase in total knee arthroplasty (TKA) dur-
ing the last decade, with an incidence of primary TKA of more
than 180 per 100,000 inhabitants in 2010 (3). The most com-
mon reason for TKA surgery is osteoarthritis (OA). TKA is an
effective treatment to reduce pain and subjective disability in
patients with OA of the knee, but several studies have shown
that muscle strength deciency (4–6) and functional limitations
can persist for several years after surgery (7, 8).
A meta-analysis showed that functional physiotherapy
exercises after TKA could have small to moderate short-term
benets 3–4 months postoperatively for physical function,
range of joint motion and quality of life, but these benets
were no longer evident at 1-year of follow-up (9). Only one
of these studies has explored the efcacy of a home-based
rehabilitation (10). That study reported encouraging ndings
that home-based rehabilitation decreased pain and disability
equally compared with in-patient rehabilitation. Since that
meta-analysis, several new intervention studies have been
published, but none of them have studied the effect of unsu-
pervised home-based exercise (11–16).
Home-based exercise programmes have some advantages
compared with clinically based supervised exercise interven-
tions, which are expensive, as they require special facilities,
equipment and trained personnel (11). Moreover, not all
patients are willing to participate in group exercises, due to
scheduling and transportation problems.
The aim of this study was to investigate the efcacy of a
12-month home exercise programme on pain, disability (West-
ern Ontario and McMaster Universities Osteoarthritis Index,
WOMAC), health-related quality of life (HRQoL) and physical
performance, compared with normal care after primary unilat-
eral TKA. We hypothesized that the long-term postoperative
home exercise programme would decrease pain and disability
and improve HRQoL more than normal care when assessed 14
months after surgery.
PARTICIPANTS AND METHODS
This study was implemented from January 2008 to February 2010.
Subjects were recruited from participants selected for TKA in the
EFFICACY OF A 12-MONTH, MONITORED HOME EXERCISE PROGRAMME
COMPARED WITH NORMAL CARE COMMENCING 2 MONTHS AFTER TOTAL
KNEE ARTHROPLASTY: A RANDOMIZED CONTROLLED TRIAL
Mirja Vuorenmaa, PT, MSc1, Jari Ylinen, MD, PhD1, Kirsi Piitulainen, PT, MSc1, Petri Salo, PT,
PhD1, Hannu Kautiainen, BA2,3, Maija Pesola, MD, PhD4 and Arja Häkkinen, PhD1,5
From the 1Department of Physical Medicine and Rehabilitation, Central Finland Health Care District, Jyväskylä,
2Department of General Practice, Unit of Primary Health Care, Helsinki University Central Hospital, Helsinki, 3Unit of
Primary Health Care, Turku University Hospital, Turku, 4Department of Orthopaedics and Traumatology, Central Finland
Health Care District and 5Department of Health Sciences, University of Jyväskylä, Jyväskylä, Finland

167
Efcacy of a home exercise programme after TKA
Central Finland Health Care District, with a population of 270,000,
during preoperative orientation visits to the Jyväskylä Central Hospital
Out-Patient Clinic. Inclusion criteria were: (i) diagnosed knee OA;
(ii) primary arthroplasty of the knee in question; and (iii) age over 18
years. Exclusion criterion were: (i) other surgery for the lower limbs
planned to be performed within 12 months; (ii) dementia; (iii) bro-
myalgia; (iv) other serious co-morbidities preventing active training;
and (v) difculty visiting a physiotherapist due to a long travelling
distance. Of the total of 301 participants screened, 191 were excluded.
The most common reason for exclusion was a long travelling distance
to follow-up visits, and the most common medical reason was serious
heart disease preventing active training. Two participants withdrew
from the study before randomization, one due to back surgery planned
within 12 months and one due to a frail post-operative condition. A
total of 108 volunteer participants were randomized into the exercise
group (EG, n = 53) or control group (CG, n = 55), using a randomiza-
tion list computer-generated by Medstat (17). Block randomization
(size of 4) was undertaken separately for men and women by a person
not working with the participants. The randomization was performed
before baseline measurements.
The questionnaires and physical performance tests were undertaken
2 months after the operations, at the time when the intervention started,
and 12 months thereafter, i.e. 14 months after surgery. In addition the
SF-36 and WOMAC questionnaires were completed at 6 months after
baseline. The intervention prole is shown in Fig. 1.
All of the outcome measurements were obtained by two physio-
therapists who were blinded to the treatment group assignment. The
participants also completed a questionnaire before the operations,
concerning their demographic and clinical characteristics.
The study plan was approved by the ethics committee of the Central
Finland Care Health District. The study protocol was explained to
the participants, who provided written consent prior to participation.
The study has been registered in the ClinicalTrials.gov database
(NCT00605124).
Operation and early rehabilitation during the rst 2 months
postoperatively
All of the participants underwent cemented TKA. All of the operations
were performed with a tourniquet, which was released after cement-
ing the components, and haemostasis was achieved before closing.
Standard medial parapatellar exposure was used. The anterior cruciate
ligament, menisci and osteophytes, when present, were removed. The
femoral and tibial bone cuts were performed with the help of appro-
priate jigs, according to preoperative planning. Fitting with a trial
prosthesis was performed, and necessary balancing of the ligaments
was undertaken. If it was necessary to balance the posterior cruciate
ligament, it was scaried, and posterior stabilising components were
used. Patellar resurfacing was performed only if the patellar articu-
lating surface was poor, causing patellar maltracking. Postoperative
Fig. 1. Knee arthroplasty study owchart.
Not eligible for the study, n=191
- bilateral arthroplasty, n=29
- planned contralateral knee
replacement, n=10
- medical reason, n=48
- living too far from hospital, n=104
Paents selected for knee
arthroplasty due to
osteoarthris n=301
Operaon n=110
Control group
n=55
Exercise group
n=53
Analysed aer 12 months
of training
n=55
Analysed
n=53
Randomised n=108
Baseline (2 months postoperavely)
Lost to follow-up n=1
Re-operaon n=1
Lost to follow-up
n=2
Enrollment
Allocaon
Follow-up
Analysis
Not eligible for the study, n=2
- back operaon, n=1
- frail condion, n=1
Quesonnare aer
6 months of
training
J Rehabil Med 46

168 M. Vuorenmaa et al.
drainage was not routinely performed. Correct positioning of the
components was ascertained postoperatively with routine X-rays.
On the second day after the operations, all of the participants were al-
lowed to perform full weight-bearing on the operated leg or as much as
they could tolerate. For safety reasons, crutches were recommended for
4–5 weeks after the operations. In accordance with normal procedures, the
postoperative hospital stay was one week. On discharge from hospital the
participants received advice concerning the application of cold packs and a
written exercise programme, which included active and passive knee range-
of-motion exercises, knee exor and extensor exercises, and hip abductor
and extensor exercises in the standing position, using the weight of an
extremity as resistance. Participants were instructed to perform these exer-
cises 1–2 times per day, with 10–15 repetitions. The participants were also
advised to be active, gradually increasing their walking distance over time.
Intervention
The participants randomized to the EG were given individual guidance
at baseline (2 months post-operatively) and at 1 and 4 months thereafter
by the same physiotherapist. At each visit, they received written infor-
mation on the exercises and were instructed to keep a weekly exercise
diary, in which they recorded the number of home exercise sessions
they completed, as well as adverse events. They were also permitted to
telephone or visit the physiotherapist if more advice was needed. The
EG exercise programmes are shown in Appendix SI1.
Baseline (2 months post-operatively). The programme consisted of isomet-
ric strengthening exercises for the quadriceps and hamstrings muscles at
multiple knee joint angles, performed in a sitting position. In the functional
exercises, the participant’s body weight was used as resistance: rising on
the toes, rst on both legs and then on one leg. In the step exercises, a step
height of 20 cm, which is the standard step height of stairs, was used. At the
beginning, the participants were instructed to perform 2 series of 10 rep-
etitions daily. They were instructed to increase the number of repetitions
in each successive set by 1 or 2, up to a maximum of 20 repetitions and
then to increase the number of series to 3. The physiotherapist telephoned
the participants after the rst 2 training weeks to ensure that there were
no adverse events or any problems with the programme.
One-month check-up visit (3 months post-operatively). The new exer-
cise programme included the following: (i) squats; (ii) hack squats with
the back held against the wall; and (iii) step exercise with a 30 cm high
gym bench. In both of the squat exercises, a 60º knee angle in the down
position was used. The participants started performing 15 repetitions
with 1–2 kg dumbbells in both hands for additional resistance. When
the participants were able to perform 20 repetitions and 3 sets, they
were then requested to increase the weight of the dumbbell by 1–2
kg. The participants had to purchase their own dumbbells for use at
home. They were instructed to continue exercising 3 times per week.
Four-month visit (6 months post-operatively). The progressions of the
previously used exercises (i–iii) were increased. In the squat and hack
squat exercises, the participants were instructed to increase the knee angle
from 60º to 90º. In the squat exercise, the participants were instructed to
increase the load on the operated side by shifting the body weight more to
the operated leg by placing a book under the opposite leg. Participants were
recommended to exercise 3 times per week, and they were encouraged
to continue training up to the 12-month follow-up. They were provided
with postage-paid envelopes to return exercise diaries on a monthly basis.
Flexibility exercises. These consisted of hamstring and triceps surae
stretching exercises in a standing position, and quadriceps and hip
exor stretching in a prone position. Each stretch was to be held for 30
s with 5 repetitions, and it was to be performed after strength training.
Control group. The CG did not receive any additional guidance after
the baseline measurements, in accordance with normal care.
Outcomes
The participants completed a questionnaire to obtain demographic
characteristics and health and work status. Weight and height were
measured to calculate body mass index (BMI). Disability was assessed
with the WOMAC questionnaire, which consists of 3 subscales: pain
(5 questions); stiffness (2 questions); and functional difculties (17
questions). Each question was graded on a visual analogue scale,
ranging from 0 to 100 mm, with 100 indicating the worst possible
situation (18). The Finnish version of the WOMAC questionnaire has
been validated previously (19).
HRQoL was measured using the Short Form-36 Health Survey (SF-
36), which contains 8 dimensions: physical functioning (PF); physical
role (RP); bodily pain (BP); general health (GH); vitality (VT); social
functioning (SF); emotional role (RE); and mental health (MH). Each
subscale is scored from 0 to 100, with higher scores indicating better
health status. In addition, the 8 scales of the SF-36 were aggregated into
2 summary scores: the Physical Component Summary Score (PCS),
comprising PF, RP, BP and GH; and the Mental Component Summary
Score (MCS), comprising VT, SF, RE and MH (20).
The Timed Up and Go test (TUG-test) was used to measure basic
mobility (21). The interclass correlation coefcients of the TUG test
has been reported to be 0.80 among TKA patients (22).
Active and passive knee range of motion (ROM) were measured us-
ing a standard, plastic long-arm goniometer with the subject positioned
in the supine position (23). In a recent study, the ICC of a long-arm
goniometer when measuring the active and passive ROM of a knee
joint was reported to vary between 0.89 and 0.97 (24).
Maximal walking speed without shoes was measured using the GAI-
TRite Walkway System (CIR Systems Inc., Sparta, USA). Participants
were instructed to walk barefoot as rapidly as possible, but still safely.
The participants started walking from a point 2 m in front of the mat,
and stopped at a point 2 m beyond the mat. The ICC of the maximal
walking speed, measured with the GAITRite Walkway System used
here, was reported to be 0.89 (25).
The isometric knee flexion and extension strength levels were
measured using a fixed dynamometer (Ds Europe, mod. 546QTD
strain gauge, Milan, Italy) (5). During measurements, the participants
were seated with the knee and hip joints at 70º flexion, and a security
strap was placed over the pelvis to prevent use of the body muscles.
After 3 submaximal repetitions for warm-up, the participants were
instructed to perform 3 maximal muscle contractions with a 1-min
rest period following each effort. If the third performance improved
by more than 5% over the best result, an additional trial was per-
formed. The best result of each measurement was used in the final
analysis. The ICC of isometric strength measurements was reported
to be 0.96 (26).
Statistical analysis
Statistical analysis was performed according to intention to treat (ITT)
principles. The data are presented as means with standard deviations
(SD) and totals with percentages. Ninety-ve percent condence
intervals (95% CIs) are reported for the most important outcomes.
Comparisons between the groups were performed using the t-test,
the χ2 test, or analysis of covariance (ANCOVA), with the baseline
values as covariates. Repeated measures for continuous outcomes
were analysed using a mixed model approach, with the unstructured
correlation structure data for an appropriate contrast. Hochberg’s
approach for multiple comparisons was applied to correct levels of
signicance for multiple testing, if appropriate (27).
Sample-size estimation. The intended sample size was based on the
primary hypothesis (WOMAC subscale for pain). Assuming a mean
difference of 6 in change in WOMAC pain score between the groups
at 12 months (SD 10), a sample size of 100 (50 in each group) was
required to detect an effect size of 0.50 at alpha of 0.05 and power of
85%. The drop-out rate was estimated to be 10%.
1http://www.medicaljournals.se/jrm/content/?doi=10.2340/16501977-1242.
J Rehabil Med 46

169
Efcacy of a home exercise programme after TKA
RESULTS
The preoperative demographic and clinical characteristics of
the groups are shown in Table I. There were no differences
between the groups, except that the duration of pain in the
operated knee was longer in the CG.
At baseline, the WOMAC subscale scores for pain (EG 23 [SD
18] vs CG 23 [SD 18]) stiffness (EG 37 [SD 24] vs CG 37 [SD
26]) and functional difculty (EG 26 [SD 20] vs CG 27 [SD 20])
did not differ between the groups. In the EG and CG, the mean
decreases in the respective subscales were –15 (95% CI –20 to
–10) and –14 (95% CI –19 to –9) for pain, –25 (95% CI –32 to
–18) and –17 (95% CI –24 to –9) for stiffness, and –18 (95% CI
–24 to –12) and –13 (95% CI –19 to –8) for functional difculty
(Fig. 2). In both groups, the mean changes in all of the WOMAC
subscales scores were statistically signicant (p < 0.001), but no
signicant differences between the groups were found.
At baseline, the PCS of the SF-36 (EG 31 [SD 7] vs in CG
33 [SD 7]) and MCS of the SF-36 ([EG 51 [SD 11] vs CG 51
[SD 11]) did not differ between the 2 groups. The mean changes
of 8 (95% CI 6 to 11) in the EG participants and 6 (95% CI 4
to 9) in the CG in PCS (p < 0.001) and those of 4 (95% CI 1
to 7) in the EG and 3 (95% CI 0 to 6) in the CG in MCS were
statistically signicant (p < 0.001), with no between-group
differences at any time-point (Fig. 3).
With regard to the physical performance variables, the EG
improved statistically signicantly in knee exion strength and
maximal walking speed, compared with the CG (Table II). Both
groups improved signicantly in knee extension strength, TUG
test time and the ROM of the operated knee, but no signicant
differences between the groups were found. After adjustment for
multiple comparisons, a statistically signicant difference between
the groups was found in maximal walking speed (p = 0.0064).
Compliance and safety
During the rst 6 months, 72% of the participants in the EG
performed the planned training sessions at least twice per week
according to the training diaries. After that period, the training
diary data were insufciently complete to be included in any
analysis. According to the 12-month questionnaire, 49% of
the EG and 34% of the CG performed exercises at least once
Table I. Preoperative demographic and clinical characteristics of the
study population
Variable
Group
Exercise
(n = 53)
Control
(n = 55)
Demographic characteristics
Female, n (%)
Age, years, mean (SD)
Body mass index, kg/m2: mean (SD)
Employed, n (%)
Education, years, mean (SD)
Family status, cohabitating, n, (%)
30 (57)
69 (8)
31 (5)
9 (17)
9 (4)
34 (64)
36 (65)
69 (9)
31 (6)
9 (16)
9 (3)
35 (64)
Clinical characteristics
Earlier knee operations, n (%)
operated knee
arthroscopy
osteotomy
knee arthroplasty
contralateral knee
arthroscopy
osteotomy
knee arthroplasty
Duration of knee pain, months (SD)
General health
Comorbidity, n (%)
cardiovascular disease
diabetes
neurological disease
pulmonary disease
other chronic disease
27 (51)
6 (11)
0 (0)
14 (26)
2 (4)
15 (28)
66 (61)
12 (23)
11 (21)
2 (4)
7 (13)
6 (11)
23 (42)
3 (5)
0 (0)
11 (20)
6 (11)
17 (31)
109 (104)
12 (22)
8 (15)
1 (2)
5 (9)
5 (9)
SD: standard deviation.
Fig. 2. Changes in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscale scores from baseline to 12-month follow-up.
Boxes show means, and whiskers show 95% condence intervals.
Mean change from baseline in Womac
J Rehabil Med 46

170 M. Vuorenmaa et al.
per week during the last month (p = 0.24). For those who had
been exercising regularly, the mean exercise frequency was 3.5
(SD 2.2.) times per week in the EG and 4.2 (SD 2.6.) times per
week in the CG (p = 0.40). More participants in the CG received
additional advice for knee exercises in a local healthcare centre
or in a private physiotherapy service, compared with the EG
(38 vs 17%, p = 0.008). Participants in both groups reportedly
engaged in leisure-time physical activities for a similar amount
of time, mean 4.7 (SD 3.5) times per week (EG) vs 4.0 (SD
2.5) times (CG) (p = 0.55).
In the EG, 5 participants discontinued the training due to pain
during exercising: 2 participants reported knee pain on the oper-
ated side, 1 reported pain on the contralateral side, 1 reported
back pain, and 1 reported hip pain. In addition, 5 discontinued
training because they were satised with their painless knees
and were no longer motivated to engage in training. One par-
ticipant was re-operated on due to a reduced range of motion,
which was considered to be caused by arthrobrosis. All of these
participants were included in the intention-to-treat analysis.
DISCUSSION
The long-term home exercise programme in this study im-
proved physical performance by increasing maximal walking
speed and knee exion strength signicantly more in the EG
compared with the CG. Both groups showed marked improve-
ments in self-reported pain, disability and HRQoL, but no
differences were found between the groups.
During the intervention, which commenced 2 months post-
operatively, the WOMAC pain, disability and stiffness subscale
scores decreased in both groups, but no between-group differences
were observed, either at 6 or 12 months after baseline. Also, in
the home-based exercise study by Kramer (10), no differences
between the intervention groups were found in any subscale scores
of WOMAC assessed 12 months after surgery. Kramer et al. (10)
compared home-based and clinically based exercise programmes
implemented between weeks 1 and 12 after TKA. One difference
between the present study and the study by Kramer et al. (10) was
that, in the present study, the intervention started 2 months after
surgery, while the other study started 2 weeks postoperatively.
In previous studies in which an intervention was started 2
months post-surgery, as in the present study, and lasted 3–12
weeks, no differences were found between the training and con-
trol groups in any WOMAC subscale scores over 6 or 12 months
of follow-up (14, 15, 28). However, Moffet (28) reported that
a supervised exercise programme decreased WOMAC pain and
functional difculty subscale scores signicantly more in the
intervention group than in the normal care group immediately
following the intervention, which lasted 2 months longer. How-
ever, these differences disappeared by the 12-month follow-up.
Kauppila et al. (15), comparing normal care and multidisciplinary
rehabilitation after surgery, did not show between-group differ-
ences in any of the WOMAC subscales 12 months after surgery.
Piva et al. (14) compared 2 different 6-week functional training
programmes and found no signicant differences in WOMAC
pain or stiffness subscales scores at 6 months of follow-up.
Fig. 3. Changes in the Physical (PCS) and the Mental (MCS) Component
Summary Scores of the Short Form-36 questionnaire (SF-36) from
baseline to 12-month follow-up. Boxes show means, and whiskers show
95% condence intervals.
Mean change from baseline in SF-36
Table II. Outcome measurements of physical performance at baseline (2 months postoperatively) and after 12 months of training
Baseline Changes from baseline to 12 months after training p-value
between
groupsa
Exercise group
Mean (SD)
Control group
Mean (SD)
Exercise group
Mean (95% CI)
Control group
Mean (95% CI)
Isometric strength of operated knee, kg
Extension
Flexion
18.2 (8.9)
10.3 (4.7)
14.8 (7.8)
10.1 (5.1)
15.1 (12.5 to 17.6)
4.4 (3.1 to 5.7)
13.1 (10.1 to 16.1)
2.4 (1.3 to 3.4)
0.50
0.009
Maximal walking speed, m/s 1.36 (0.44) 1.35 (0.37) 0.32 (0.26 to 0.38) 0.17 (0.11 to 0.24) < 0.001
Timed Up and Go test, s 9.5 (2.8) 10.5 (3.6) –1.58 (–2.53 to –0.63) –1.43 (–2.01 to –0.85) 0.16
Range of motion of operated knee, degree
Passive extension decit
Active extension decit
Passive exion
Active exion
5.0 (5.1)
9.0 (5.0)
104.0 (13)
99.0 (13)
4.3 (4.9)
8.3 (4.6)
103.0 (17)
100.0 (17)
–3.7 (–5.1 to –2.4)
–5.9 (–7.3 to –4.5)
13.2 (10.6 to 16.1)
14.4 (11.5 to 17.4)
–3.5 (–4.6 to –2.4)
–6.0 (–7.0 to –5.0)
13.9 (10.1 to 17.7)
14.2 (10.1 to 18.1)
0.72
0.45
0.86
0.98
aAnalysis of covariance; baseline value as covariate.
SD: standard deviation; 95% CI: 95% condence interval.
J Rehabil Med 46

171
Efcacy of a home exercise programme after TKA
Both groups in the present study improved similarly in
HRQoL. Accordingly, in the study by Kramer (10), HRQoL,
measured using SF-36, improved similarly in both the home-
based and in-patient rehabilitation groups over a 12-month
follow-up. Moffet et al. (28) found small, but signicant,
differences in favour of the intensive functional rehabilitation
group in the PCS and MCS scores of the SF-36, compared with
usual care group after a 2-month intervention period, but the
differences disappeared during the 12 months of follow-up.
Kauppila et al. (15) found no signicant difference in HRQoL
measured using 15D at any follow-up point.
Despite the extended home programme not yielding greater
improvements in WOMAC pain or HRQoL, it did have some
positive effects on physical performance. Faster maximal walk-
ing speed was found in the EG than in the CG. This observation
was meaningful because walking is a basic human function, and
limitations in walking increase the risk for disability (29) and
dependency (30), and reduce social networks (31). Normal walk-
ing speed among persons aged 60–69 years has been found to
be a mean of 1.29 m/s, which is approximately 30% slower than
maximal speed (32, 33). To cross at a light-controlled crossing
requires a walking speed of approximately 1.2 m/s (34), which is
thus the speed required to cope as a pedestrian in ordinary trafc
conditions. At baseline, more than one-third of the participants
in both groups did not reach that speed, even if they walked at
maximal speed. At the 12-month follow-up, more than 90% of
the participants in the EG reached 1.2 m/s in walking speed,
while in the CG, the corresponding proportion was 79%.
Moreover, the home exercise programme yielded greater knee
exion strength in the EG, compared with controls. Greater knee
muscle strength and knee motion have been reported to have a
positive effects on balance (35) and on the prevention of falling
(36). In the present study, the CG also gained knee muscle strength,
which might be partly explained by the advice received from local
healthcare centres or from private physiotherapy practices or by the
increase general physical activity. Valtonen et al. (37) also found
that, in the exercise group, while the benets achieved in knee
exor and extensor muscle power were maintained, the mobility
benets (habitual walking speed and stair ascending time) disap-
peared at 12 months after the cessation of training. They concluded
that habitual physical activity was sufcient to maintain muscle
power in sedentary people. In contrast, in the study of Bade et
al. (38), stair climbing and walk test results remained better in
the high-intensity programme group than in the low-intensity
programme group at the 52-week follow-up. In their study, the
training period started immediately after TKA and lasted 8 weeks,
and even high-intensity resistance and eccentric training was well
tolerated. In the present study, the training programme started 2
months after the operations, because we wanted to allow for early
healing of wounds and soft tissue so that knee pain, effusion or
movement limitations would not complicate the training (28).
The long-term home programme had a low cost and appeared
to be well tolerated, as only 2 participants reported pain in the
operated knee, and no major complications were reported. The
programme consisted of functional exercises, which are easy
to perform progressively. The participants were instructed to
exercise 3 times per week. According to the training diaries,
during the rst 6 months, 72% of the participants exercised at
least twice per week, which has been proposed to be sufcient
to increase strength (16). Over the next 6 months, training com-
pliance declined, and the strength increase was consequently
less than expected. Five participants discontinued the exercise
programme due to pain and 5 because they were satised with
their painless knees and were no longer motivated to train. To
improve compliance, it might be possible in clinical practice to
offer modied exercises, such as water gymnastics or treatment
for pain. It is more difcult to improve exercise compliance in
participants who are satised with the results of their surgery
and thus are not motivated to persist with long-term training.
In shorter interventions and in supervised training studies,
training compliance has been easier to maintain (14, 28).
The strength of the present randomized controlled study was
the long training period, compared with the 3–12 weeks used in
earlier intervention studies (12, 14, 15, 28). The study also had
only a few drop-outs. According to the 12-month questionnaire
responses, exercise compliance decreased considerably during
the last month, and the training diaries were insufciently com-
pleted during this period. Thus, a limitation of the study was poor
exercise compliance. A home-based exercise programme might
require a larger number of booster contacts to promote better
exercise adherence and progression (39, 40). Participants with
pain might need effective therapies to abolish pain in order to
increase their exercise compliance. In the present study, several
participants received exercise guidance from other healthcare
providers, and more often in the control group, which might
have had inuence on the results. Other limitations include lack
of local reliability data for the objective tests.
In conclusion, a 12-month home-based exercise programme,
which commenced 2 months after TKA, did not improve index
knee pain beyond the improvement achieved by usual care.
However, the exercise programme had some positive effects
on objectively measured physical performance. The exercise
programme was suitable for use at home for most participants
and was easy to implement in general practice. However, means
to increase exercise adherence must be further developed.
ACKNOWLEDGEMENTS
This study was supported in part by a grant from the Central Finland
Health Care District. The authors have no conicts of interest to declare.
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