The Effects of Femoral Nerve Blockade in Conjunction with
Epidural Analgesia After Total Knee Arthroplasty
Jacques T. YaDeau, MD, PhD*, Janet B. Cahill, PT†, Mark W. Zawadsky, MD‡,
Nigel E. Sharrock, MBChB*, Friedrich Bottner, MD‡, Christine M. Morelli, BS*,
Richard L. Kahn, MD*, and Thomas P. Sculco, MD‡
Departments of *Anesthesia, †Rehabilitation, and ‡Orthopaedic Surgery, Hospital for Special Surgery, Weill Medical
College of Cornell University, New York, New York
proves analgesia and rehabilitation after total knee ar-
throplasty. No study has evaluated the combination of
femoral nerve blockade and epidural analgesia. In this
prospective, randomized, blinded study we investi-
femoral nerve block with 0.375% bupivacaine and 5
?g/mL epinephrine; 39 patients served as controls. All
patients received combined spinal-epidural anesthesia
and patient-controlled epidural analgesia with 0.06%
bupivacaine and 10 ?g/mL hydromorphone. Average
duration of epidural analgesia was 2 days. All patients
received the same standardized physical therapy inter-
vention. Median visual analog scale (VAS) scores with
physical therapy were significantly lower for 2 days
among patients who received a femoral nerve block
versus controls: 3 versus 4 (day 1), 2.5 versus 4 (day 2);
P ? 0.05. Median VAS pain scores at rest were 0 in both
groups on days 1 and 2. Flexion range of motion was
improved on postoperative day 2 (70° versus 63°; P ?
0.05). No peripheral neuropathies occurred. We con-
clude that the addition of femoral nerve blockade to
the first 2 days after total knee arthroplasty.
(Anesth Analg 2005;101:891–5)
ment of functional outcomes (2,3). Multiple techniques
of postoperative pain control have been used after
TKA, including oral or IM opioids, patient-controlled
IV opioids, patient-controlled epidural analgesia
(PCEA), and single-dose or continuous femoral nerve
block (CFNB). Reliance on opioids has been associated
with inadequate pain control and frequent side effects
such as nausea, sedation, and confusion (1). Postoper-
ative epidural analgesia provided pain relief that was
superior to pain relief from IV opioids (1,2,4). The
addition of a FNB to postoperative IV analgesia after
TKA resulted in significantly better pain control, less
frequent morphine-related side effects, more rapid
otal knee arthroplasty (TKA) can cause severe
postoperative pain (1). Improved control of post-
operative pain facilitates more rapid achieve-
achievement of physical therapy (PT) milestones, and
shorter hospital stay (5). However, other investigators
found that FNB did not improve analgesia after TKA
except in the recovery room (6).
In comparison with epidural analgesia after TKA,
CFNB plus sciatic nerve block caused less nausea and
had more patients with no pain (7). Analgesia after
CFNB without a sciatic nerve block was equivalent (8)
or inferior (9) to epidural analgesia. CFNB alone did
not reduce nausea compared to epidural analgesia
(8,9). CFNB plus sciatic nerve block allowed earlier
ambulation and earlier discharge (versus epidural) (7),
but CFNB alone did not improve rehabilitation versus
epidural (8). Epidural 1% lidocaine (with clonidine
and morphine) caused more dysesthesia, urinary re-
tention, and hypotension than occurred when the
same mixture was used for CFNB (9). CFNB with
bupivacaine improved range of motion (ROM) on day
1 but did not reduce pain or side effects when com-
pared with placebo (10). CFNB may (8,9), or may not
(7) cause less urinary retention than epidural analge-
sia. One study found a 40% rate of epidural catheter-
related problems (lateralized, kinked, or difficult in-
sertion) versus 0% with CFNB (8). However, insertion
of CFNB may have an 18% complication rate (11).
Supported, in part, by the Research Fund of the Anesthesiology
Department of the Hospital for Special Surgery.
Presented, in part, at the American Academy of Orthopedic Sur-
geons, March 2004, San Francisco, California.
Accepted for publication January 28, 2005.
Address correspondence to Jacques T. YaDeau, Hospital for Spe-
cial Surgery, Weill Medical College of Cornell University, 535 E.
70th St., New York, NY 10021. Address e-mail to email@example.com.
©2005 by the International Anesthesia Research Society
0003-2999/05Anesth Analg 2005;101:891–5
In our review of the literature we did not find
studies of a FNB combined with PCEA after TKA. We
investigated whether the addition of a single injection
FNB to continuous epidural analgesia improved post-
operative pain control, accelerated achievement of re-
habilitation milestones, or lessened side effects.
This prospective, randomized, blinded study was ap-
proved by the Hospital for Special Surgery IRB. The
primary outcome variable was flexion ROM (a major
rehabilitation functional milestone). A Student’s t-test
sample size calculation (Sigma Stat, Jandel Scientific)
using published data (9) indicated that 80 patients
gave a power of 0.838 to detect a 10° difference in
mean flexion ROM on day 2, with a 15° standard
deviation, ? of 0.05. The 10° difference was chosen
because it exceeds the accepted 5° variability in gonio-
metric measures and because, clinically, a 10° increase
in knee flexion allows the patient to more closely
approximate the ROM necessary for functional tasks
(12). Secondary outcome variables included rehabili-
tation functional milestones, pain reported by patients
(visual analog scale [VAS] scores at rest and with PT),
and side effects such as nausea, pruritus, and confusion.
PT outcomes measured included knee flexion ROM,
continuous passive motion range, ambulation distance,
postoperative day (POD) achieving unassisted transfer
in and out of bed, walker ambulation, cane ambulation,
non-reciprocal stair negotiation, and length of stay.
After written informed consent was obtained, 80
patients of a single surgeon were enrolled. Inclusion
criteria consisted of primary TKA for a diagnosis of
osteoarthritis and age ?85 yr. Exclusion criteria con-
sisted of previous knee trauma, previous surgery to
the operative knee including arthroscopic or open me-
niscectomy, peripheral neuropathy, chronic preopera-
tive opioid usage, a nonpalpable femoral artery, or
previous lower extremity vascular bypass surgery.
Patients were randomized into two groups using
computer-generated random numbers and a closed
envelope design. The patients, the physical therapists,
the pain management team, and the chart analysts
were not informed of the patients’ group assignment.
Patients were told during the informed consent dis-
cussion that a FNB, if performed, would result in
motor blockade and decreased sensation of the ante-
rior thigh. Forty-one patients received a single-dose
FNB before combined spinal-epidural anesthesia. Ex-
tent and type of sedation before the FNB was at the
discretion of the anesthesiologist. A 22-gauge insu-
lated Stimuplex (B Braun) needle was inserted lateral
to the femoral pulse at the level of the inguinal crease.
Bupivacaine 0.375% with 5 ?g/mL epinephrine,
30 mL, was injected after eliciting a quadriceps con-
traction at ?0.5 mAmp. The FNB was performed in
the operating room (OR). Success of the block could
not be evaluated in the OR, as the combined spinal-
epidural anesthetic was initiated immediately after
conclusion of the FNB. Thirty-nine control patients
did not receive a FNB. The block was not evaluated
after surgery, as we wished to preserve the blinding of
the patients as much as possible.
Patients in both groups received combined spinal-
epidural anesthesia with subarachnoid administration
of 12.5 mg of 0.5% bupivacaine. The combined spinal-
epidural anesthetic was sufficient for surgery in all
patients. The epidural catheter was not used during
surgery. Postoperative PCEA was provided with
0.06% bupivacaine and 10 ?g/mL hydromorphone.
Initial settings were a continuous rate of 3–6 mL/h
with 4 additional 5 mL patient-controlled boluses al-
lowed per hour. PCEA settings were subsequently
adjusted by the pain service as needed. Patients were
offered oral analgesics (hydrocodone/acetaminophen or
oxycodone/acetaminophen) on the second POD. Epi-
dural analgesia was discontinued after successful transi-
tion to oral analgesics, typically on either the second or
the third POD. Urinary catheters were placed in all pa-
tients in the recovery room and were typically continued
until the epidural catheter was removed. As all patients
had urinary catheters, effects of the analgesic technique
on urinary retention were not evaluated.
All patients in both groups received the same stan-
dardized postoperative PT. A PT evaluation in the
recovery room of lower extremity strength and sensa-
tion was recorded. Patients’ lower extremity strength
and sensation were reassessed daily. Although formal
quadriceps strength was not assessed because of pain
and the nature of the surgical procedure, quadriceps
buckling in standing (inability to stand as a result of
inadequate quadriceps strength) was viewed as an
indication of profound weakness. The following stan-
dardized rehabilitation protocol was applied to both
groups. The continuous passive motion (CPM) ma-
chine was initiated (0°–60°) in the recovery room, and
was increased as tolerated on subsequent days. There
was no specific target ROM. ROM was progressed
based on patient comfort and ability in a blinded
fashion. The CPM was used for 4–6 h daily. Transfer
Table 1. Patient Characteristics
72 ? 8
81 ? 20
33 PS, 8 CCK
73 ? 8
79 ? 15
29 PS, 10 CCK
Tourniquet Time (min)
Anesthesia Time (min)
Values are mean ? sd or median (25%–75% percentiles).
PS ? posterior stabilized; CCK ? condylar constrained knee.
Anesthesia time was defined as elapsed time from patient arrival in the
operating room until arrival in the postanesthesia care unit.
FEMORAL NERVE BLOCK / EPIDURAL ANALGESIA
YADEAU ET AL.ANESTH ANALG
training and weight bearing as tolerated gait training
were initiated on the first POD. Patients were ad-
vanced from a rollator walker to a standard cane
according to their functional ability. Active knee flex-
ion, passive extension, and muscle strengthening ex-
ercises were also initiated on the first POD. Knee ROM
was measured using a universal goniometer in the
seated position; hip and knee were aligned with the
foot placed on the floor. Patients received PT from a
physical therapist or a rehabilitation technician twice
daily during the week and daily on weekends. Daily
PT sessions (with a physical therapist) included gait
and transfer training, ROM exercises, and strengthen-
ing exercises. A second daily mobilization practice
session under the supervision of a rehabilitation tech-
nician repeated the transfers and ambulation done in
the previous session by the physical therapist.
Patient demographics and surgical details were re-
corded. All patients were followed by standard pain
service protocols, which included repeated docu-
mented assessment by nurses for pain, nausea, pruri-
tus, sedation, and confusion. Patients were evaluated
by the attending anesthesiologist on the pain service
for satisfactory recovery from anesthesia, including
complete resolution of the nerve block. VAS pain
scores were determined by nurses every 2 h after
surgery. Pain scores that did not coincide with PT
sessions were analyzed as pain at rest. VAS scores
with activity were recorded during PT sessions. Anal-
gesic requirements, volume of epidural medication,
VAS scores, and side effects attributed to analgesics
were recorded. Achievement of rehabilitation functional
milestones was recorded by physical therapists. Physical
therapists were blinded as to study assignment.
The data distributions of all the variables were ex-
amined. Means and sd or medians and quartiles were
obtained. Data for Table 1 are presented as mean ? sd
if data passed a normality test. Student’s t-test was
used to evaluate normally distributed data. Data for
Table 1 that did not pass a normality test are presented
as median (25%–75% percentiles). A Mann-Whitney
rank sum test was used to evaluate data that were not
normally distributed. Data for Table 2 are presented as
median (25%–75% percentiles). Correction was made
for multiple comparisons as indicated. The ROM data
were analyzed using repeated-measures analysis of vari-
ance. The pain data are ordinal and were not normally
distributed. A Mann-Whitney U-test was performed be-
The VAS scale is an integer scale; therefore nonparamet-
ric statistics were used to evaluate VAS scores.
Forty-one patients received a FNB and epidural anal-
gesia; 39 patients received epidural analgesia alone.
Combined spinal-epidural anesthesia was achieved in
all patients. Patients in each group were similar in age,
ASA physical status, weight, surgical and anesthesia
times, and component use (Table 1).
Patients who received a FNB had significantly lower
VAS scores with PT on POD 1 (median, 3 versus 4)
and 2 (median, 2.5 versus 4) (Fig. 1). On POD 1, VAS
scores ?6 during PT were reported in 11 of 39 (28%)
control patients versus 4 of 41 (10%) FNB patients (P ?
0.045, Fisher’s exact test). On POD 2, VAS scores
?6 during PT were reported in 12 of 39 (31%) control
patients versus two of 41 (5%) FNB patients (P ?
0.0062, Fisher’s exact test). Median pain scores at rest
were low in both groups (Fig. 1). The volume of epi-
dural medication delivered to both groups was similar
Table 2. Physical Therapy Outcomes
31 rehabilitation, 10 home
Flexion ROM day 1 (degrees)
CPM day 1 (degrees)
Flexion ROM day 2 (degrees)*
CPM day 2 (degrees)
Flexion ROM day 3 (degrees)
CPM day 3 (degrees)
Ambulation distance day 1 (feet)
Ambulation distance day 2 (feet)
Ambulation distance day 3 (feet)
First transfer from bed (day)
First use of walker (day)
First use of cane (day)
First use of stairs (day)
Length of stay (days)
Disposition30 rehabilitation, 9 home
Values are median (25%–75% percentiles).
ROM ? range of motion; CPM ? continuous passive motion.
* P ? 0.05, Mann-Whitney U-test.
FEMORAL NERVE BLOCK / EPIDURAL ANALGESIA
YADEAU ET AL.
On POD 1, some members of both groups of pa-
tients had decreased strength or sensation in the op-
erative leg. Among patients who received FNB, 29%
strength and 34% had decreased sensation. Among
control patients, 3% had buckling because of de-
creased quadriceps strength and 13% had decreased
sensation. Strength and sensation were determined by
the physical therapist. If the patient demonstrated
quadriceps buckling on standing, ambulation training
was deferred until the patient had adequate quadri-
ceps control in standing. The study design did not
control for time from block until assessment. All pa-
tients had adequate quadriceps strength in standing
without buckling that allowed for safe progressive
gait training by POD 2. It is not part of the current
practice to use Jordan splints or knee immobilizers for
Patients who had received a FNB had significant
improvement in flexion ROM on POD 2 (Table 2). No
differences were noted for other PT outcomes including
ambulation distance, independent transfer, CPM flexion,
CPM progression, use of a walker, and progression to
cane use, stair use, or length of stay (Table 2).
The incidence of side effects was not significantly
different between groups. During the first three PODs,
nausea was reported (one or more times) in 27% of the
FNB patients and 28% of the controls. Corresponding
numbers for pruritus were 49% (FNB patients) and
39% (controls). One (3%) of the control patients and
none of the FNB patients became confused during the
first 3 PODs.
Catheters were removed on POD 1 in 4 patients (2 in
the FNB group; one for back pain, one for bilateral
numbness; 2 in the control group; one for confusion,
one for epidural site leakage). The rate of premature
discontinuation was 5%. Sixty-one catheters were re-
moved on POD 2 (34 in the FNB group, 27 in the
control group). Fifteen catheters were removed on
POD 3 (5 in the FNB group, 10 in the control). No
patient withdrew from the study.
No patients had residual numbness, dysesthesia, or
weakness associated with FNB or combined spinal-
Single-injection FNB combined with epidural analge-
sia using a low concentration of local anesthetic (0.06%
bupivacaine ? 10 ?g/mL hydromorphone) improved
pain relief with PT and improved one measure of
alone. Epidural analgesia alone provided excellent
pain relief at rest. Previous studies have demonstrated
that either epidural analgesia (1,2,4) or FNB (5) im-
proved analgesia and rehabilitation after TKA com-
pared with systemic opioids.
Figure 2. Daily volume of epidural medication. The box depicts the
25th and 75th percentiles. Horizontal lines represent the median
(50th percentile), and the bars depict the 10th and the 90th
Figure 1. Pain visual analog scale (VAS). VAS scores are depicted in
pairs, with the patients who received a femoral nerve block (“B”) to
the left of the control patients (“C”). The box depicts the 25th and
75th percentiles. Horizontal lines represent the median (50th per-
centile), and the bars depict the 10th and the 90th percentiles. *P ?
0.05 (blocked versus control). A, VAS scores with physical therapy.
B, VAS scores at rest.
FEMORAL NERVE BLOCK / EPIDURAL ANALGESIA
YADEAU ET AL. ANESTH ANALG
The duration of analgesia observed in this study Download full-text
from the FNB (through POD 2) was longer than had
been anticipated. A single-injection FNB typically pro-
vided analgesia for no longer than 24 h after anterior
cruciate ligament reconstruction or TKA (5,13–15).
Only 34% of patients in this study had signs of sensory
blockade when evaluated on POD 1 (which may have
been ?24 h postinjection), and no patients had resid-
ual FNB on POD 2. In another study, all patients
reported weakness of thigh muscles after TKA even if
given a nerve block with saline (10).
FNB benefited one measure of PT (active knee flex-
ion ROM on POD 2) and did not slow any aspect of
PT. Increased knee flexion allows patients to perform
tasks with less compensatory motion and allows pa-
tients to emphasize other goals, such as obtaining
complete extension and independent mobilization. In
addition, the criterion for discontinuing the use of
CPM at this institution is active flexion to 90° for 2
consecutive days. Thus early increases in flexion result
in earlier discontinuation of this passive modality and
shift the emphasis of the rehabilitation program to
more active exercises.
This study did not demonstrate reduction of
analgesic-related side effects by adding FNB to PCEA.
Patients given FNB had less pain, used similar doses
of epidural narcotic, and had the same rate of side
effects as did control patients. With PCEA, patients
self-administer medication boluses until their pain is
entirely controlled or they encounter side effects that
induce them to stop activating the bolus mechanism. It
is possiblethat patients
hydromorphone/bupivacaine to themselves until side
effects became prominent.
Routine FNB does not require much additional
time, as evidenced by the similar anesthesia times in
the 2 groups (109 min for control versus 110 min for
FNB group). Anesthesia time included time to per-
form the FNB. The small difference between the two
groups indicated that in the context of TKA, little
additional time is needed in the OR to perform a FNB.
There are several methodological issues to consider.
This study evaluated the addition of a single-injection
FNB to postoperative epidural analgesia. We did not
study CFNB catheters. All patients received postoper-
ative epidural analgesia. All patients received urinary
catheters. We could not assess the role of the epidural
analgesia in causing nausea, vomiting, or urinary re-
tention. The epidural catheter was not tested by ad-
ministration of concentrated local anesthetic, as this
was considered likely to delay the patients’ recovery
from the anesthetic. In an attempt to maintain blind-
ing, we also did not assess the success of the FNB. We
did not standardize the duration of epidural analgesia;
instead the duration was determined by clinical as-
sessment of the patients’ need for epidural analgesia.
In conclusion, addition of FNB to epidural analgesia
significantly improved analgesia for the first 2 PODs
after TKA and improved knee flexion on POD 2. FNB
did not affect achievement of other PT functional
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