Abstract
Background: It is currently unknown whether functional restrictions
following total hip arthroplasty can reduce the prevalence of early
postoperative dislocation. Our hypothesis was that dislocation was more likely
to occur in patients who were not placed on these restrictions.
Methods: We performed a prospective, randomized study to evaluate
the role of postoperative functional restrictions on the prevalence of
dislocation following uncemented total hip arthroplasty through an
anterolateral approach. Of the 630 eligible consecutive patients, 265 patients
(303 hips) consented to be randomized into one of two groups (the
"restricted" group or the "unrestricted" group). The
patients in both groups were asked to limit the range of motion of the hip to
<90° of flexion and 45° of external and internal rotation and to
avoid adduction for the first six weeks after the procedure. The patients in
the restricted group were instructed to comply with additional hip precautions
during the first six weeks postoperatively. Specifically, these patients were
managed with the placement of an abduction pillow in the operating room before
bed transfer and used pillows to maintain abduction while in bed; used
elevated toilet seats and elevated chairs in the hospital, in the
rehabilitation facility, and at home; and were prevented from sleeping on the
side, from driving, and from being a passenger in an automobile. All patients
were followed for a minimum of six months postoperatively.
Results: There was one dislocation in the entire cohort (prevalence,
0.33%). This dislocation occurred in a patient in the restricted group during
transfer from the operating table to a bed with an abduction pillow in place.
Patients in the unrestricted group were found to return to side-sleeping
sooner (p < 0.001), to ride in automobiles more often (p < 0.026), to
drive automobiles more often (p < 0.001), to return to work sooner (p <
0.001), and to have a higher level of satisfaction with the pace of their
recovery (p < 0.001) than those in the restricted group. There was an
additional expenditure of approximately $655 per patient in the restricted
group.
Conclusions: Total hip arthroplasty through an anterolateral
approach is likely to be associated with a low dislocation rate. Removal of
several restrictions did not increase the prevalence of dislocation following
primary hip arthroplasty at our institution. However, it did promote
substantially lower costs and was associated with a higher level of patient
satisfaction as patients achieved a faster return to daily functions in the
early postoperative period.
Level of Evidence: Therapeutic Level I. See Instructions
to Authors for a complete description of levels of evidence.
A multitude of factors contribute to dislocation after total hip
replacement, including component malposition, surgical approach, and
soft-tissue-related
factors1-7.
Patient education is thought to be a key element in the prevention of this
complication5,8.
To enforce the importance of avoiding extremes of motion and largely to
protect the softtissue repair, various postoperative restrictions have been
proposed for patients undergoing total hip
arthroplasty9.
Although early perioperative restrictions (such as the use of an in-hospital
abduction pillow, the use of a pillow between the legs during sleep, the use
of a high chair and an elevated toilet seat, the limitation of certain ranges
of motion, and the avoidance of driving or being a passenger in an automobile)
are frequently recommended, the value of these restrictions in preventing
early dislocation has not been evaluated. A recent prospective study
demonstrated that the rate of early dislocation was acceptably low in patients
who did not observe post-operative restrictions following total hip
arthroplasty10.
That study, however, was not randomized and lacked a comparison group. The
present randomized, prospective study was specifically designed to elucidate
whether there was a difference in the prevalence of dislocation within six
months after total hip arthroplasty among patients who did not observe a
standard set of precautions.
Demographics
The study group comprised 265 patients (303 hips) who underwent
uncemented primary total hip arthroplasty through an anterolateral approach
between March and December 2002 at our institution (see Appendix). The
patients included 139 male patients and 126 female patients with a mean age of
58.3 years (range, fourteen to eighty-eight years) (p = 0.39). There were no
significant demographic differences between the groups. The mean body mass
index was 29.3 kg/m2 (range, 15.9 to 50.2 kg/m2) for the
patients who were managed with full hip precautions (the
"restricted" group) and 28.7 kg/m2 (range, 17.6 to 45.7
kg/m2) for those who were not (the "unrestricted"
group) (p = 0.34).
Inclusion Criteria
All patients undergoing primary total hip arthroplasty were eligible for
inclusion. Institutional approval for the study was obtained, and all patients
gave informed consent. The exclusion criteria included a history of surgery on
the ipsilateral hip, hyperflexibility syndromes, and neuromuscular compromise
(e.g., Alzheimer or Parkinson disease). Patients who did not give informed
consent also were excluded. Of the 630 patients (725 hips) who were managed
with primary total hip arthroplasty during the study period, 365 patients (422
hips) elected not to enroll in the study or were excluded. No patients were
excluded for hyperflexibility, Alzheimer disease, or Parkinson disease.
Risk-aversion to the study's protocol was the most common reason cited for
nonparticipation, as some patients did not want to be assigned to the
"unrestricted" group. Other patients declined to participate
because of the time commitment required to take part in the study. Thus, the
patients in the study group represented 42.1% of all patients (41.8% of all
hips) who were managed with primary total hip arthroplasty during this
time-interval.
Surgical Data
With the exception of the study variables, the preoperative,
intraoperative, and postoperative management was the same for the patients in
both groups. All patients underwent neuraxial anesthesia. All surgical
procedures were performed by or under the direct supervision of one of the
senior authors (R.H.R., W.J.H., or P.F.S.). All procedures involved the use of
a cementless femoral stem (Accolade; Stryker Orthopaedics, Mahwah, New Jersey)
and acetabular cup (Trident PSL; Stryker Orthopaedics). All arthroplasties
were performed through a modified Hardinge anterolateral approach with the
patient in the supine
position11-13.
The size of the components was determined on the basis of preoperative
template measurements and intraoperative assessment. The most common femoral
head size used was 28 mm, although the size of the femoral head varied on the
basis of the size of the acetabular component, the type of liner (highly
cross-linked polyethylene or ceramic), the age of the patient, and the
preference of the surgeon (see Appendix). For patients who received a
polyethylene liner, a 22-mm head was used when the cup size was =46 mm, a
28-mm head was used when the cup size was 48 to 56 mm, and a 32-mm head was
used when the cup size was =58 mm. During the years of this study, 36-mm
femoral heads were introduced. A 36-mm femoral head was used for four patients
who received a cup with a diameter of 60 mm. For patients who received a
ceramic liner in association with the Trident acetabular shell system, a 28-mm
femoral head was used when the cup size was 46 to 48 mm, a 32-mm head was used
when the cup size was 50 to 56 mm, and a 36-mm head was used when the cup size
was 58 to 68 mm.
The desired position of the acetabular component was 30° to 40° of
abduction and 10° to 15° of anteversion. The femoral canal was
prepared with sequential broach trials in 10° to 15° of anteversion.
The soft-tissue tension was optimized through a combination of neck-length and
offset adjustments until an axial force with the leg in extension produced 1
to 2 mm of soft-tissue laxity for male patients and 2 to 3 mm of soft-tissue
laxity for female patients. During trial reductions, stability of the hip was
tested in full flexion (100° to 120°); 90° of flexion and 30°
of adduction; full extension (20° to 30°); 0° of extension and
45° of internal-external rotation; and 0° of extension, 30° of
adduction, and 45° of external rotation with and without knee flexion (up
to 90°). Such stability testing is routine in our practice and was not
modified for the present study.
Once the final femoral stem and head were impacted into place, the abductor
mechanism was repaired with nonabsorbable sutures in an interrupted fashion.
The fascia and the subcutaneous tissue also were repaired with absorbable
sutures in a similar manner.
Study Protocol
All eligible patients were approached preoperatively, and those who were
interested in participating in the study gave consent. The details of the
study were discussed, and it was emphasized that all patients would be
expected (1) to limit the range of motion of the hip for the first six weeks
to <90° of flexion and 45° of external and internal rotation and
(2) to avoid adduction (crossing the legs). In addition, all patients were
allowed to bear weight as tolerated and were allowed to use a walking aid for
as long as they thought it was needed. The purpose of the study, as explained
to patients, was to determine whether or not additional hip precautions were
truly necessary. Patients were informed about the process of randomization
into one of two groups, with the patients being either
"restricted" or "unrestricted" by the need to observe
additional precautions. Randomization was performed preoperatively with use of
a random-numbers table, but the designation of patients to either the
restricted or the unrestricted protocol was double-blinded until the
completion of wound closure in order to avoid any patient-selection bias or
any alteration in surgical technique. Sealed envelopes that had been made only
by the study coordinator were opened at the end of surgery, before bed
transfer, to reveal a patient's group assignment.
In addition to the restrictions placed on both groups, the patients in the
restricted group were managed with the placement of an abduction pillow in the
operating room before bed transfer; used pillows to maintain abduction while
in bed; used elevated toilet seats and elevated chairs in the hospital, in the
rehabilitation facility, and at home; and were prevented from sleeping on the
side, from driving, and from being a passenger in an automobile. Patients in
the unrestricted group were not required to follow any of these additional
restrictions; however, they were given the freedom to choose to use this
additional equipment, if they desired, for their comfort.
All patients were cared for by nurses and physical therapists who were
experienced in working with patients managed with total joint replacement. All
rehabilitation facilities to which patients were transferred were informed of
the study protocol so that the patients in the unrestricted group would not be
unduly restricted and would not be made to deviate from their study protocol.
Detailed written postoperative instructions were reviewed with each patient by
the study coordinator before discharge to ensure that each patient understood
his or her assigned study protocol. At the time of discharge from the
hospital, the patients were given a followup survey to be used as a
self-administered diary to track progress and compliance. These completed
surveys were returned to us at the time of the first postoperative visit, six
weeks after surgery. A final survey was completed at the time of the second
follow-up visit, approximately six months after surgery. Patients who were not
able to return for follow-up or who did not complete their surveys were
contacted by telephone and/or mail.
Patients were followed for a minimum of six months. In both surveys,
patients were asked to record (1) the percentage of time that they followed
each of four range-of-motion restrictions (<90° of flexion while
bending over, <90° of flexion while sitting, avoidance of leg
adduction, and <45° of internal and external rotation), (2) the
specific additional equipment that they used (an elevated chair and toilet
seat, pillows for leg abduction, a walker, crutches, or a cane), and (3) the
postoperative time-point when they stopped using the additional equipment (see
Appendix). In addition, they were asked a series of activity-related questions
regarding the percentage of time spent sleeping on the back as opposed to the
side, the level of comfort when sleeping in these positions, and the amount of
time before they resumed sleeping on the side, before they resumed riding in
or driving an automobile, and before they returned to work. At the time of
both surveys and any subsequent follow-up contacts, patients were specifically
asked to confirm whether or not the hip had dislocated. At the time of the
six-week survey, patients were also asked the number of times that they had
driven or had been a passenger in an automobile. At the time of the six-month
survey, all patients were asked the percentage of their usual daily activities
that they could now perform, patients in the restricted group were asked why
they were noncompliant (if applicable), and patients in the unrestricted group
and patients who had had a previous contralateral hip replacement were asked
to rate the ease of their recovery given their assigned study protocol. The
accuracy of the patient-reported information was further confirmed by
discussions with family members and health-care personnel. Finally, a
standardized questionnaire designed to evaluate patient satisfaction was
completed by the patients preoperatively, at six weeks, and at six months (see
Appendix).
Statistical Analysis
Statistical analysis was performed with use of a chi-square test with a
continuity correction for discrete variables. A onetailed Student t test was
used for continuous variables, and the level of significance (a) was set
at p < 0.05. Before the beginning of the study, a power analysis was
performed (with the value of a set at 0.05, with the value of ß set
at 0.80, and with use of the historic dislocation rate at our institution of
approximately 1.0%) to detect a threefold difference in the dislocation rates.
This analysis indicated that a minimum of 260 hips (a minimum of 130 hips in
each group) would be needed to avoid a type-II
error14,15.
A sufficient number of subjects were thus recruited to meet these
requirements, and additional subjects were recruited to allow for possible
attrition.
Prevalence of Dislocation
There was one dislocation in the entire study; this dislocation
occurred in a patient in the restricted group. Thus, the dislocation rate was
0.33% (one of 303) overall and 0.66% (one of 152) for the restricted group.
The dislocation occurred during transfer of the patient from the operating
table to a bed with an abduction pillow in place. Closed reduction was
performed, with no subsequent episodes of instability and no need for a
reoperation.
Limp
There was no difference between the two groups with regard to the
prevalence of limp. At six months, the prevalence of limp (of any degree) was
12.5% in the restricted group and 13.2% in the unrestricted group (p =
0.80).
Patient Compliance
The level of self-reported patient compliance with range-of-motion
restrictions during the first six weeks after surgery was high in both groups,
but the rate in the restricted group was significantly higher than that in the
unrestricted group (95.7% compared with 90.0%; p = 0.001). Interestingly, a
large number of patients in both groups continued to follow the
range-of-motion restrictions after the required six-week period. At a minimum
of six months postoperatively, the rate of voluntary compliance with these
restrictions was 53.5% in the restricted group and 32.9% for the unrestricted
group (p < 0.001).
Although not required to do so, some patients in the unrestricted group
elected to use some of the equipment on occasion. The difference between the
two groups with regard to the use of equipment was significant for all
categories except the use of pillows for side-sleeping
(Table I). The voluntary use of
pillows for side-sleeping was less frequent in the unrestricted group than in
the restricted group at all timeperiods, but this difference was significant
only during rehabilitation stays.
Patient Satisfaction
At the time of the six-month follow-up, patients in the unrestricted group
reported a much greater degree of satisfaction with regard to return to their
preoperative level of daily activities; specifically, patients in the
unrestricted group could perform 106.4% (range, 25% to 350%) of their
preoperative daily activities, whereas those in the restricted group could
perform 96.5% (range, 25% to 200%) of their preoperative daily activities (p =
0.015). When the patients in the unrestricted group were asked to rate their
recovery relative to the protocol used for the restricted group, 89.4%
believed that their recovery was easier than it would have been if
restrictions had been applied. The patients in the restricted group reported a
compliance rate of 95.7% for range-of-motion restrictions and a 74.3%
compliance rate for all restrictions. The most commonly cited reasons for the
25.7% noncompliance rate (p < 0.001) in this group were that some patients
were dissatisfied with the additional restrictions because of their
"knowledge of the unrestricted protocol" (6.6%, p < 0.001) and
that some patients had "planned to recover at their own pace"
anyway (18.4%, p < 0.001). The percentage of patients who were satisfied
with the pace of their recovery was greater in the unrestricted group than in
the restricted group (89.4% compared with 74.3%; p < 0.001).
Return to Activities of Daily Living
An earlier return to activities of daily living was noted in several key
areas for the patients in the unrestricted group
(Table II), which contributed
to an overall sense of greater satisfaction in that group. Patients began
side-sleeping at an average of 3.2 weeks after surgery in the unrestricted
group, compared with 5.8 weeks in the restricted group (p < 0.001).
Significant differences in side-sleeping were noted at all follow-up
time-periods. Nineteen (14.2%) of the patients in the unrestricted group began
side-sleeping on the night of surgery (p < 0.001). Sleeping fully supine
was rated as "uncomfortable" by 68.4% of the patients in the
restricted group and by 65.6% of those in the unrestricted group (p =
0.684).
Patients in both groups were passengers in automobiles for the first time
early in the recovery period. Patients in the unrestricted group were
passengers for the first time at a mean of 1.5 weeks (range, 0.3 to 20.0
weeks) and took a mean of 16.8 trips (range, one to 100 trips) during the
first six weeks. Patients in the restricted group were passengers for the
first time at a mean of 1.9 weeks (range, zero to 6.1 weeks) and took a mean
of 6.7 trips (range, zero to fifty trips) during the first six weeks (p =
0.026 and p < 0.001, respectively).
Patients in the unrestricted group drove an automobile for the first time
earlier and more often in the first six weeks than those in the restricted
group did. Patients in the unrestricted group drove for the first time at a
mean of 4.9 weeks and took a mean of 17.3 trips in the first six weeks,
whereas those in the restricted group drove for the first time at a mean of
6.8 weeks and took a mean of 5.9 trips during the first six weeks (p <
0.001 for both comparisons). Finally, patients in the unrestricted group
returned to work at a mean of 6.5 weeks whereas those in the restricted group
returned at a mean of 9.5 weeks (p < 0.001). Fifty percent of the working
patients in the unrestricted group returned to work less than six weeks after
surgery, compared with only 18.8% of those in the restricted group (p <
0.001). All ninety-eight of the working patients in the unrestricted group had
returned to their usual jobs after six months of follow-up, compared with only
eighty-one of eighty-five patients in the restricted group (p = 0.096).
Duration of Hospitalization
There was no significant difference between the two groups with regard to
the duration of hospitalization. The mean hospital stay was 3.5 days (range,
two to five days) for patients in the restricted group and 3.5 days (range,
two to eight days) for those in the unrestricted group (p = 0.88). However,
the number of patients who required a rehabilitation stay was significantly
higher in the restricted group than in the unrestricted group (125 hips
compared with 100 hips; p < 0.002).
Costs
The lack of a need for additional equipment and devices in the unrestricted
group was associated with a cost savings of approximately $655 per patient.
This included the cost for an abduction pillow ($120), an elevated toilet seat
($65), and an elevated chair ($995 to purchase or $15 per day to rent). This
finding does not take into account the cost of transport required by the
patients in the restricted group or the loss in wages because of the delay in
returning to work for the patients in the restricted group.
Post-Study Statistical Analysis
As no patients were lost to follow-up, the additional subjects who had been
recruited beyond the minimum requirement of 130 hips per group increased the
power of the study to ß > 0.85 for an a of
0.0514.
To our knowledge, the present report is the first randomized,
prospective study that has evaluated the effectiveness of the most commonly
used restrictions designed to prevent dislocation during the first six months
following total hip arthroplasty. The process of blinding both surgeons and
patients with regard to the group assignments was continued until completion
of wound closure in order to avoid the introduction of any bias in patient
selection or surgical technique. The protocol was well defined and patients
were followed in a strict manner. We believe that the study was nonselective
and, although important exclusion criteria were observed, we believe that it
included all eligible and consenting patients. The unknown effect of
abandoning long-standing restrictions on the dislocation rate and the
intensive time commitment required to complete the questionnaires and
telephone conversations dissuaded some patients from taking part in the study.
Patients who declined to participate may have been more risk-averse than those
who participated. Nevertheless, the patients who participated had a wide
spectrum of diagnoses (including obesity) and demographic characteristics. Our
findings suggest that patients are much more satisfied when fewer restrictions
are imposed on them following hip arthroplasty. They regain their autonomy and
resume daily activities faster, enjoy better sleep, and even return to work
earlier once they can drive.
A large number of patients in the present study observed the restrictions.
Overall, patients in the restricted group were an average of 73.1% compliant
with all aspects of their protocol. The patients in the unrestricted group
were less compliant than those in the restricted group with regard to
range-of-motion restrictions at six weeks. Patients in the unrestricted group
also were less likely to restrict their motion voluntarily at six months. The
most common reasons that patients in the restricted group were noncompliant
and in violation of the protocol were that they did not obtain an elevated
chair for home use and did not use pillows when supine in bed or for
side-sleeping.
Another benefit of removing some of the traditional hip precautions is the
associated economic savings. The estimated cost savings in this study were
substantial, and the environmental burden associated with discarding equipment
such as abduction pillows was reduced.
The present study had some limitations. First, it is conceivable that
despite the pre-study power analysis and inclusion of a relatively large
number of patients, the lack of a significant difference between the two
groups with regard to the rate of dislocation was the result of a type-II
statistical error. We believe that this is unlikely given the increased
statistical power in the post-study statistical analysis. In addition, a
recent retrospective review of postoperative complications in more than 1000
patients undergoing total hip arthroplasty at our institution revealed that
the rate of early dislocation continues to be <1% despite the abandonment
of most patient restrictions.
Second, all of the hip arthroplasties in the present series were performed
through an anterolateral approach, which is believed to be associated with a
lower rate of dislocation than the posterolateral
approach3,16,17.
Hence, the applicability of these findings to total hip arthroplasties
performed through approaches other than the anterolateral approach remains
questionable. In addition, all procedures were performed by or under the
direct supervision of experienced surgeons who each perform more than 500
total hip arthroplasties annually. Moreover, these hip replacements were
performed with the patient in a supine position, which affords improved
accuracy of acetabular component positioning and restoration of limb
length18. The
combination of these factors could have contributed to the already low
dislocation rate in the study group.
Third, the present study evaluated patients undergoing uncomplicated
primary hip arthroplasty and excluded those with predisposing factors to hip
instability such as previous hip surgery and potential abductor weakness,
neurological conditions, hyperflexibility, or other connective-tissue
disorders. Last, and perhaps most important, all patients in the present study
were clearly instructed to avoid crossing their legs, to avoid hip flexion
beyond 90°, and to avoid excessive rotation that could jeopardize
soft-tissue and abductor repairs for six weeks postoperatively. We believe
that it is important for patients to be given detailed instructions regarding
these range-of-motion precautions in order to allow better soft-tissue healing
because patient education still remains critical for avoiding dislocation and
other complications following joint arthroplasty.
We conclude that the imposition of restrictions other than the limitation
of extremes of motion did not influence the prevalence of early dislocation in
this group of patients managed with uncemented total hip arthroplasty through
an anterolateral approach. On the basis of the initial findings of the present
study, we now ask all patients to comply with the range-of-motion restrictions
(that is, the avoidance of flexion of >90°, leg adduction, and external
and internal rotation of >45°) for six weeks postoperatively, but we
have discontinued the use of in-hospital abduction pillows, the avoidance of
sidesleeping, the use of a pillow between the legs while supine in bed and for
side-sleeping, the avoidance of driving or being a passenger in an automobile,
and the use of an elevated chair or toilet seat.
A table presenting demographic data and details related to the surgical
procedure and also the follow-up questionnaires are available with the
electronic versions of this article, on our web site at
(go to
the article citation and click on "Supplementary Material") and on
our quarterly CD-ROM (call our subscription department, at 781-449-9780, to
order the CD-ROM). ?
Note: The authors thank the Rothman Institute research staff for
their assistance with data collection and patient follow-up surveys, and
Rebecca R. Peak, MStat, for her assistance with the statistical analysis.
Demos HA, Rorabeck CH, Bourne RB,
MacDonald SJ, McCalden RW. Instability in primary total hip arthroplasty with
the direct lateral approach. Clin Orthop.2001;393:
168-80.393168
2001
[PubMed][CrossRef]
Ali Khan MA, Brakenbury PH, Reynolds IS.
Dislocation following total hip replacement. J Bone Joint Surg
Br.1981;63:
214-8.63214
1981
[PubMed]
Masonis JL, Bourne RB. Surgical
approach, abductor function, and total hip arthroplasty dislocation.
Clin Orthop.2002;405:
46-53.40546
2002
[PubMed][CrossRef]
Mulliken BD, Rorabeck CH, Bourne RB,
Nayak N. A modified direct lateral approach in total hip arthroplasty: a
comprehensive review. J Arthroplasty.1998;13:
737-47.13737
1998
[PubMed][CrossRef]
Paterno SA, Lachiewicz PF, Kelley SS.
The influence of patient-related factors and the position of the acetabular
component on the rate of dislocation after total hip replacement. J
Bone Joint Surg Am.1997;79:
1202-10.791202
1997
Woo RY, Morrey BF. Dislocations after
total hip arthroplasty. J Bone Joint Surg Am.1982;64:
1295-306.641295
1982
[PubMed]
Joshi A, Lee CM, Markovic L, Vlatis G,
Murphy JC. Prognosis of dislocation after total hip arthroplasty. J
Arthroplasty.1998;13:
17-21.1317
1998
[CrossRef]
Morrey BF. Difficult complications after
hip joint replacement. Dislocation. Clin Orthop.1997;344:
179-87.344179
1997
[PubMed]
Charnley J. Total hip replacement by
low-friction arthroplasty. Clin Orthop.1970;72:
7-21.727
1970
[PubMed]
Talbot NJ, Brown JH, Treble NJ. Early
dislocation after total hip arthroplasty: are postoperative restrictions
necessary? J Arthroplasty.2002;17:
1006-8.171006
2002
[PubMed][CrossRef]
Glassman AH, Engh CA, Bobyn JD. A
technique of extensile exposure for total hip arthroplasty. J
Arthroplasty.1987;2:
11-21.211
1987
[CrossRef]
Hardinge K. The direct lateral approach
to the hip. J Bone Joint Surg Br.1982;64:
17-9.6417
1982
[PubMed]
Stephenson PK, Freeman MA. Exposure of
the hip using a modified anterolateral approach. J
Arthroplasty.1991;6:
137-45.6137
1991
[CrossRef]
Fleiss JL. Statistical methods
for rates and proportions. 2nd ed. New York: Wiley; 1981.
p 42-6.42
1981
Billote DB, Glisson SN, Green D, Wixson
RL. A prospective, randomized study of preoperative autologous donation for
hip replacement surgery. J Bone Joint Surg Am.2002;84:
1299-304.841299
2002
[PubMed]
Mallory TH, Lombardi AV Jr, Fada RA,
Herrington SM, Eberle RW. Dislocation after total hip arthroplasty using the
anterolateral abductor split approach. Clin Orthop.1999;358:
166-72.358166
1999
[PubMed]
Ritter MA, Harty LD, Keating ME, Faris
PM, Meding JB. A clinical comparison of the anterolateral and posterolateral
approaches to the hip. Clin Orthop.2001;385:
95-9.38595
2001
[PubMed][CrossRef]
Austin MS, Hozack WJ, Sharkey PF,
Rothman RH. Stability and leg length equality in total hip arthroplasty.
J Arthroplasty.2003;18(3
Suppl 1): 88-90.1888
2003
[PubMed][CrossRef]