1. The Journal of Arthroplasty Vol. 13 No. 4 1998
Preoperative Physical Therapy in Primary
Total Knee Arthroplasty
J e f f r e y A. R o d g e r s , M D , * K e v i n L. G a r v i n , M D , * C r a i g W. W a l k e r , M D , t
D e e M o r f o r d , RN, M P A , * J o s h U r b a n , M D , * a n d J o e B e d a r d , B S t
Abstract: In order to evaluate the efficacy of preoperative physical therapy for
patients undergoing elective primary total knee arthroplasty, l0 patients completed 6
weeks of physical therapy before surgery (PT group). Ten patients served as controls
(C group). Subjects were tested at baseline (PT only), before surgery, 6 weeks after
surgery, and 3 months after surgery using the Hospital for Special Surgery knee rating
scale, range of motion, thigh circumference, walking speed, Cybex II isokinetic knee
flexion, and extension testing, and computed tomography scanning for cross-
sectional muscle area. Hospital stay and need for physical therapy after inpatient
rehabilitation were also compared. Physical therapy produced modest gains in
isokinetic flexion strength in these severely arthritic knees but no difference in
extension strength. The decrease in isokinetic strength after surgery was not affected
by preoperative physical therapy. Muscle area did not decrease significantly for the PT
group, but it did decrease for the C group after surgery. While postoperative strength
differences could not be demonstrated, preoperative physical therapy preserved thigh
muscle area after surgery. The clinical significance of this finding is uncertain.
Consequently, this study failed to support the routine use of preoperative physical
therapy in knee replacement surgery. Key words: preoperative physical therapy,
range of motion, osteoarthritis.
Despite advancements and research in surgical tech- strength loss beyond the age of 50 years [4]. In
nique, prostheses, and modalities of rehabilitation, addition, a negative nitrogen balance develops fol-
scant attention is paid to preoperative physical lowing major orthopaedic procedures [5]. Consider-
preparation of the patient for w h o m total knee ing this list of compounding factors, patients under-
arthroplasty (TKA) has been prescribed. Weakness going total knee replacement begin the long journey
of both the quadriceps and hamstrings, in contrast to recovery substantially disadvantaged.
to the contralateral limb, is commonly observed in While the large body of knowledge evaluating
patients with osteoarthritis of the knee [1,2]. After postoperative physical therapy, including continuous
TKA, significant further atrophy of the quadriceps passive m ot i on (CPM) and electrical stimula-
has been shown histologically [3]. An age-related tion [6-12] continues to grow, the role of preopera-
decline in overall muscular strength also begins in tive physical therapy in TKA has not been estab-
adulthood with a significant increase in the rate of lished, and research is extremely limited as to its
efficacy [2,13]. The ability of the elderly to respond
to heavy resistance strength training, however, has
From the Departments of *Orthopaedic Surgery and y-Radiology,
University of Nebraska Medical Center, Omaha, Nebraska. been clearly demonstrated [14-16]. While it may
Reprint requests: Jeffrey A. Rodgers, MD, Des Moines Ortho- seem that patients with severe osteoarthritis may be
paedic Surgeons, P.C., 6001 Westown Parkway, West Des Moines, unable to complete a successful preoperative physi-
IA 50266.
Copyright © 1998 by Churchill Livingstone® cal therapy program, well-designed studies have
0883 -5403/1304-000853.00/0 shown both feasibility and effectiveness of strength
414

2. Preoperative PTin PrimaryTKA • Rodgers et al. 415
training in patients with knee osteoarthritis [ 17,18]. The HSS knee score was performed by the senior
The purpose of this controlled investigation was to investigator or his resident staff, while the remain-
evaluate prospectively the effects of preoperative der of the testing was performed by a certified
physical therapy on short-term outcome variables physical therapist. The duration of hospitalization,
following primary TKA. need for posthospitalization physical therapy, and
complication rates were also compared.
Materials and Methods
Muscle Area
Study Population All patients also were examined with a "single-
From December 1992 to August 1995, patients slice" CT examination of both thighs for muscle area
scheduled by the senior author of this report for using a previously described technique [16] at
unilateral primary TKA for osteoarthritis were re- baseline (PT only), before surgery and at 6 weeks
cruited to participate in the study. Patients with a after surgery (Fig. 1). The cross section of interest
history of uncontrolled hypertension, cerebral aneu- was established using the midpoint between the
rysm, unstable angina, or any other contraindica- center of the femoral head and the medial femoral
tion to high-intensity physical exertion or testing condyle. The absolute measurement from the cen-
were excluded. According to the Investigational ter of the femoral head to the midpoint of the
Review Board-approved protocol, patients were femoral shaft was used for subsequent scans. The
assigned to the control (C) group or the physical images were analyzed using MTRACE (University of
therapy group (PT) based on their geographic avail- Iowa, 1992) on a SUN image-processing station.
ability. Those from the focal metropolitan area were Gray scale levels ->i corresponded to muscle and
invited to participate in the PT group, while those those ~<0 corresponded to fat. The bone was ex-
living too far to attend the physical therapy sessions cluded using the region of interest function. The
were invited to participate in the C group. Origi- number of pixels for each group were then counted
nally, 11 patients were enrolled in the C group; one and converted to square centimeters. Using this
withdrew from the protocol for personal reasons, technique, intramuscular fat was excluded.
which left a group of I0 to complete the study.
Group C comprised five m en and five w o m e n with
an average age of 65 years (range, 50-83). The
Intervention
original PT group enrolled 12 patients, two of these The PT group completed 6 weeks of preoperative
discontinued the protocol: one patient's operation physical therapy three times per week under the
was cancelled because of occult coronary artery direction of a certified physical therapist. Each
disease and the other was unable to perform the patient's program was individualized according to
physical testing because of fibromyalgia. The remain- their baseline physical capacity and reevaluated and
ing 10 patients who completed the preoperative advanced accordingly after 3 weeks. Exercises in-
physical therapy protocol included four m en and six cluded stretching and warm-up, heel-slides, isomet-
women, with an average age of 70 years (range, ric quadricep sets, straight leg raises, short-arc quad-
63-78). There was no statistical difference in the age ricep sets, standing squats, step-ups, and bicycling.
or sex distribution of the two groups. One of the Both groups received preoperative physical therapy
patients in the control group had undergone contra- instruction in the usual postoperative exercise pro-
lateral TKA 1 year before the study, otherwise all tocol.
other patients had native knees. All patients were reconstructed using the same
posterior-stabilized cemented total knee implant
(Insall-Burstein II, Zimmer, Warsaw, IN). They re-
Physical and Functional Testing
ceived the same postoperative physical therapy
Before surgery subjects were tested at baseline including ankle pumps, quadricep sets, straight leg
(PT only), and then at 6 weeks and 3 months after raises, short-arc quadricep sets, heel-slides, assisted
surgery. Testing and measurement included Hospi- flexion, calf-stretching, hamstring-stretching, ham-
tal for Special Surgery Knee Rating Scale (HSS Knee string sets, hip abduction, and hip adduction exer-
Score) [19], range of motion, Cybex II (Lumex Inc., cise. Patients started gait-training (weight-bearing
Ronkonkoma, NY) isokinetic knee flexion and exten- as tolerated) beginning on the first postoperative
sion testing (3 practice trials followed by 3 testing day. Depending on the patient's progress and living
trials at 60°/s and 180°/s), walking speed (10 m situation, patients were either discharged to home
normal and tandem gait), and thigh circumference. with instructions for a home physical therapy pro-

3. 416 The Journal of Arthroplasty Vol. 13 No. 4 June 1998
Fig. 1. Mid-thigh "single slice" computed tomography scan analysis. (A) Representative CT scan with region of interest
function activated. (B) Histogram of Gray scale distribution: -->1represents muscle and <--0represents fat.
gram or transferred to a geriatric rehabilitation Results
center for supervised physical and occupational
therapy. At the discretion of the senior author,
outpatient physical t h e r a p y was prescribed postop- Physical and Functional Testing
eratively as necessary, regardless of their study The groups did not differ significantly with respect to
group designation. extension and flexion range of motion over time,
although a trend toward decreased motion was demon-
Statistical Analysis strated for both groups at the 6-week evaluation
Statistical analysis of the data included Repeated (Table 1). The thigh circumference and 10-m walk
Measure Analysis of Variance to compare the trends times also did not differ significantly over time for either
b e t w e e n the groups and t test: Paired Two-Sample group. Hospital for Special Surgery knee rating scores
for Means for comparison of differences within each improved for both groups at the 3-month follow-up
group. with no difference in degree of improvement (Fig 2).
Table 1. Anthropometric and Physical Testing Data
R a n g e of M o t i o n
Thigh Circumference W a l k Time
Extension Flexion HSS Score
Involved Uninvolved 10 m 10 mT
Mean Range Mean Range (cm) (cm) (s) (s) Score Range
Control
Preop 8 0-25 i13 77-i44 52 52 l0 35 54 40-67
6 weeks 9 0-28 104 84-i26 52 51 13 34
3months 6 0-20 113 80-117 5i 50 9 32 85 68-97
PT
Baseline 4 0-10 112 99-130 52 53 9 35 60 44-79
Preop 7 0-25 112 85-128 53 53 10 33
6 weeks 5 2-15 i01 85-125 51 51 12 36
3months 4 0-10 109 95-i20 52 51 10 26 87 79-95
HSS, Hospital for Special Surgery; Preop, preoperative; PT, physical test.

4. Preoperative PTin PrimaryTKA • Rodgers et al. 417
ioo 60 deg./sec.
• Control ft.lb~
80 M PT 100
60 80
60
40
40
20
20
0 0
base 3 mo Flexion Extension
F i g . 2. H o s p i t a l f o r S p e c i a l S u r g e r y k n e e r a t i n g s c o r e s . F i g . 3. P r e o p e r a t i v e p e a k f l e x i o n a n d e x t e n s i o n t o r q u e :
c o n t r o l g r o u p (60°/s).
Isokinetic Testing Data
decreased 4 0 % (P = .007) in flexion and 30%
Table 2 s u m m a r i z e s the isokinetic p e a k torque
(P = .02) in extension. The 3 - m o n t h testing re~
data for b o t h groups. At p r e o p e r a t i v e (C) and
vealed recovery to baseline strength for b o t h groups
baseline (PT) evaluation, the involved k n e e was
at 60°Is and 180°/s. Values i m p r o v e d for the PT
significantly w e a k e r for b o t h groups in flexion a n d
group f r o m 6 w e e k s to 3 m o n t h s 9 ft lb (36%) in
extension at 60°/s (Figs 3, 4) a n d for flexion at
flexion (P = .02) and 13 ft. lb (33%) in extension
180°/s for the C group only. Significant strength
(P = .002). The C group failed to d e m o n s t r a t e a
i m p r o v e m e n t w i t h training was d e m o n s t r a t e d for
statistically significant i m p r o v e m e n t during this in-
the PT group w i t h a 5 ft lb increase in flexion
terval. Overall, repeated m e a s u r e s analysis of vari-
strength at 60°Is (17%, P = .01) f r o m baseline to
ance revealed no significant difference b e t w e e n the
preoperative. Extension strength i m p r o v e d a m e a n
groups over time.
of 2 ft lb but was not significant (Figs 5, 6).
Both groups d e m o n s t r a t e d decreased p e a k - t o r q u e
Muscle Area
at 60°/s in the involved k n e e at the 6 - w e e k follow-
up. The C group decreased 2 8 % (P = .06) in flexion The cross-sectional muscle area of the thigh failed
and 30% (P = .05) in extension, while the PT group to change significantly for the PT group f r o m base-
Table 2. C y b e x I s o k i n e t i c Testing
P e a k Torque (ft-lb)
Flexion Extension
60 d e g / s 180 d e g / s 60 d e g / s 180 d e g / s
Uninv Involved Uninv Involved Uninv Involved Uninv Involved
Control
Pre-op 42a 32b 32c 26d 8in 57o 46p 42q
6 week 43 25e 34 22 79 44r 48 33
3 month 42 33f 29 28 85 56s 50 38
PT
Baseline 36g 30h 26i 21j 70t 51u 45v 35x
Pre-op 43 35k 29 25 73 53y 46 37
6 week 38 251 30 13 71 40z 46 28
3 month 39 34m 30 24 67 53aa 43 37
P vaIues a vs. b 0.03 n vs. o 0.02
paired N e s t c vs. d 0.02 p vs. q ns
b vs. e 0.06 o vs. r 0.05
e vs. f ns r VS. S ns
g vs. h 0.05 t vs. u 0.03
i vs. j ns v vs. x ns
h vs. k 0.01 u vs. y ns
k vs. 1 0.007 y vs. z 0.02
I vs. in 0.02 z vs. aa 0.002

5. 418 The Journal of ArthroplastyVol. 13 No. 4 June 1998
60 deg./se¢. 60 deg./sec.
ft.ibs. ft-lbs
80 60
Control
60 -ll-
50 PT
.,¢..
40
45
20 40
0 3 5 ~
Flexion Extension "base pre-op 6wk* 3mo
Fig. 4. Baseline peak flexion and extension torque: physi- Fig. 6. Extension peak torque over time.
cal therapy group (60°/s).
line to preoperative (Table 3) for either the involved I0 in the C group and 7 of 10 in the PT group). No
or u n i n v o l v e d extremity. Involved thigh muscle patient in either group developed clinically evident
deep venous thrombosis nor did t h e y require fob
area decreased from a m e a n of 105.3 cm 2 to 94.0
cm 2 (not significant) for the PT group, while the low-up knee manipulation for p o o r range of mo-
tion. In a follow-up "exit interview," 9 of l0 of the
area decreased from 1 I2.5 cm 2 to 90.1 cm 2 (P : .04)
patients in the PT group said they felt the preopera-
for the C group (Fig. 7). The u n i n v o l v e d extremity
tive physical t h e r a p y helped t h e m prepare for sur-
did not change significantly 6 weeks after surgery
gery, and they would do it again if they were to have
for either group. Again, repeated measures analysis
the opposite knee reconstructed.
of variance failed to demonstrate a difference be-
t w e e n groups.
Discussion
Hospitalization and Physical Therapy
Functionally, preoperative physical t h e r a p y does
Utilization
not appear to have a significant effect on range of
Acute hospital stays averaged 5 days (range, 3-9 m o t i o n or maximal walking speed. Likewise, there
days) for the C group and 6 days (range, 3-12 days) was no difference in the degree of i m p r o v e m e n t for
for the PT group. Rehabilitation unit stays were the HSS knee scores. This i n s t r u m e n t relies on
required for four patients in the control group estimations of pain and subjective measures of
(mean stay, 6 days) and for six patients in the PT function, strength, and stability [19]. Subtle differ-
group (mean stay, 4 days). Overall hospitalization ences w o u l d be difficult to detect using this mea-
(acute and rehabilitation) did not differ b e t w e e n sure, especially considering the t r e m e n d o u s impact
groups and averaged 8 days for the PT group and 7 of surgery alone.
days for the C group. Isokinetic strength testing is a reproducible and
The n e e d for additional o u t p a t i e n t physical c o n v e n i e n t m e a n s of assessment of strength in
t h e r a p y was also not different b e t w e e n groups (6 of m a n y pathologic conditions {20]. Peak torque is the
variable that is traditionally assessed in isokinetic
studies and has p r o v e n most reliable in research
applications [2i]. The observed weakness of the
60 deg./sec.
involved knees at baseline in both flexion and
ft-lbs
extension is consistent with current literature [I,20].
36 While the PT group p r o d u c e d gains in flexion
34 Control
strength with training, these gains did not translate
41" to the immediate postoperative period. The PT
32 PT
group's strength gains from 6 weeks to 3 m o n t h s
30
after surgery were significant, but the C group's
28 gains were not significant. One w o u l d not expect a
26 delayed effect of preoperative physical therapy.
24 These differences most likely represent small sample
base pre-op* 6wk* 3mo size error and the inability of this study to d e m o n -
Fig. 5. Flexion peak torque over time. strate a statistically significant difference for the C

6. Preoperative PTin PrimaryTKA • Rodgers et al. 419
Table 3. Computed Tomograpby Muscle Area
Involved Uninvolved
Total T h i g h Muscle Intramuscular Total T h i g h Muscle Intramuscular
cm 2 cm 2 Fat cm 2 %Muscle cm 2 cm 2 Fat cm 2 %Muscle
Control
Preop 261.56 112.52a 25.62 43.02 262.04 113.85 23.85 43.45
6 weeks 244.32 90.12b 27.66 36.89 251.97 111.35 21.85 44.19
PT
Baseline 285.86 I08.71c 23.49 38.03 298.73 117.04 23.8I 39.18
Preop 284.95 105.31d 24.84 36.96 295.50 114.43 22.88 38.72
6 weeks 266.67 94.00e 25.15 35.25 271.80 110.44 22. l 1 40.63
P values avs. b 0.04 *no significant differences
p a i r e d t-test cvs. d n.s.
dvs. e n.S.
group. Repeated measures analysis showed no differ- more significant differences in strength may have
ence between the groups, supporting this conten- been present, but not measured. However, we are
tion. not aware of an isotonic strength testing apparatus
Quadricep strength is essential to immediate post- that is as reliable, safe, and convenient as the Cybex
operative rehabilitation and progress in weight- II isokinetic testing device [23].
bearing [22]. Later in rehabilitation, the emergence Overall, the recovery of Both groups to baseline
of symmetrical and uniform gait also depends on strength By the 3-month evaluation was quite
increased quadricep strength [ 1]. Extension strength, remarkable. While Berman measured isokinetic
however, failed to improve with training. Patello- strength after TKA, his initial postoperative measure-
femoral pain during testing may have limited perfor- ment was performed from 3 to 6 months after
mance, although in a study of isokinetic perfor- surgery. This is the first study to evaluate isokinetic
mance of patients with osteoarthritis of the knees, strength of all patients 3 months after surgery and
Lankhorst et al. [20] felt the influence of pain on document recovery to baseline. It is important to
torque was minimal [20]. note that this "recovery" may be more a function of
One can also not ignore the effect of specificity of pain relief (allowing a better isokinetic test) than
training on strength measurement. The physical true strength gain.
therapy program utilized predominantly closed- The computed tomography (CT) muscle area data
chain, isotonic exercise, while the testing consisted provide more convincing evidence of the positive
of open-chain isokinetic measurement. This factor effect of preoperative physical therapy. While preop-
has not been investigated for diseased individuals, erative physical training failed to produce muscle
but overwhehning evidence supports exercise-type area increase, these data suggest that, after surgery,
specificity regarding isokinetic versus isotonic exer- muscle thigh area may be preserved by preoperative
cise for normal individuals [21]. Consequently, physical training. In addition, this study is the first to
definitively measure the significant muscle area
changes that occur following TKA. It is important to
note that the relatively large changes in muscle area
cm2 demonstrated By the CT analysis did not correlate
120 ~ . _ with the thigh circumference measurement.
115 - i Uninvolved In this climate of increasing pressure to limit costs
Control and decrease utilization of medical resources, all
I10 ~
4- new treatment interventions will need to be scruti-
105 ~, FT nized in this light. In this limited study, no savings in
"I
100 i
911
i [I
Involved
Control
-O-
terms of decreased hospital stay or need for post-
hospitalization physical therapy could be demon-
strated for the physical therapy. Many intangible
variables beyond the control of this study influence
PT
pre-op 6wk ~ these measures including confounding medical prob-
lems, family expectations, living arrangements, and
Fig. 7. Computed tomography muscle area over time. even day of the week of surgery.

7. 420 The Journal of Arthroplasty Vol. 13 No. 4 June-1998
Few investigators h a v e studied the effect of pre- cal analysis, a n d the UNMC D e p a r t m e n t s of Physical
operative physical t h e r a p y in TKA. W e i d e n h i e l m T h e r a p y a n d Radiology for their assistance in this
et al. [2] investigated p r e o p e r a t i v e isometric exer- study.
cise in patients scheduled for u n i c o m p a r t m e n t a l
k n e e r e p l a c e m e n t [2]. These authors d e m o n s t r a t e d
decreased self-selected walking speed p r e o p e r a - References
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