вход по аккаунту


Outcomes of obese and nonobese patients undergoing revision total hip arthroplasty.

код для вставкиСкачать
Arthritis & Rheumatism (Arthritis Care & Research)
Vol. 59, No. 5, May 15, 2008, pp 738 –745
DOI 10.1002/art.23562
© 2008, American College of Rheumatology
Outcomes of Obese and Nonobese Patients
Undergoing Revision Total Hip Arthroplasty
Objective. To evaluate the effect of obesity on the incidence of adverse events (surgical site infection, dislocation,
re-revision, or >1 adverse event), functional outcome, residual pain, and patient satisfaction after revision total hip
arthroplasty (THA).
Methods. We conducted a university hospital-based prospective cohort study including 52 obese and 152 nonobese
patients with revision THA performed between 1996 and 2006. We used incidence rates, rate ratios, and hazard ratios
(HRs) to compare the incidence of events in obese and nonobese patients and in 4 body mass index (BMI) categories (<25,
25–29.9, 30 –34.9, >35). Functional outcome and pain were measured 5 years postoperative using the Harris Hip Score.
Results. The incidence rate for >1 complication increased with rising BMI (1.8, 3.4, 10.3, and 17.9 cases/100 personyears). The increase was small between normal and overweight patients (adjusted HR 1.5, 95% confidence interval [95%
CI] 0.5, 4.7), significantly greater with BMI 30 –34.9 (adjusted HR 4.5, 95% CI 1.4, 14.0), and most evident with BMI >35
(adjusted HR 10.9, 95% CI 2.9, 41.1). The adjusted HR for surgical site infection (obese versus nonobese) was 4.1 (95% CI
1.1, 15.0) and for dislocation 3.5 (95% CI 1.3, 9.3). Eighty patients had a followup visit at 5 years. Obese patients had
moderately lower functional results and higher levels of residual pain, but patient satisfaction was almost similar.
Conclusion. Revision THA is technically challenging, particularly in obese patients, probably due to more difficult
anatomic conditions. We found an increased risk of adverse events, notably surgical site infection and dislocation in these
Obesity has been associated with a higher prevalence of
symptomatic osteoarthritis of the hip and a subsequent
increase in total hip arthroplasty (THA) procedures (1–
6). Interestingly, a recent large population-based study
(6) did not find an increase in revision procedures
among obese patients post primary THA. Prosthetic joint
infections, dislocations, and revisions are rare but serious complications after primary THA. There are conflicting results in the current literature concerning the
influence of obesity on the occurrence of these complications. A number of studies found an increase in perioperative morbidity (7–9) and complications such as
infections or dislocations associated with obesity (8,10 –
13), whereas others have reported no differences (14 –
Anne Lübbeke, MD, DSc, Guido Garavaglia, MD, Pierre
Hoffmeyer, MD: Geneva University Hospital, Geneva, Switzerland; 2Karel G. M. Moons, PhD: Julius Center for Health
Sciences and Primary Care, University Medical Center,
Utrecht, The Netherlands.
Address correspondence to Anne Lübbeke, MD, DSc, Orthopaedic Surgery Service, Geneva University Hospital, 24,
Rue Micheli-du-Crest, 1211 Geneva 14, Switzerland. E-mail:
Submitted for publication March 16, 2007; accepted in
revised form November 7, 2007.
18). The literature concerning the influence of obesity
on revision for aseptic loosening is also inconclusive,
which has partially been related to differences in activity level (15,16,18 –23). However, functional outcome
and patient satisfaction after THA have been considered
comparable or only slightly lower in obese compared
with nonobese patients (11,13,17,24).
In comparison with primary hip arthroplasty, revision
hip arthroplasty is a prolonged intervention resulting in
more extensive tissue damage and is associated with
more short- and long-term complications, as well as a
higher mortality rate (25–29). The intervention is considered to be technically challenging, particularly in
obese patients probably because of more difficult anatomic conditions. Only a few studies, notably with
short-term followup, have reported on the influence of
obesity on outcomes after revision THA (12,30,31).
There is even less literature concerning the effect of
obesity on functional outcomes and satisfaction after
revision surgery (32,33).
The aim of this study was first to evaluate the association between obesity and the incidence of main complications (in particular, surgical site infection, dislocation, and
re-revision) after revision THA up to 5 years postoperatively. Also, we aimed to determine whether functional
outcome, pain, and patient satisfaction at 5 years differed
Effect of Obesity on Revision THA
Table 1. Patient distribution*
Total number of revision THAs performed
Patients excluded because of bilateral revision
Number of eligible revision patients
Patients with missing BMI
Total number of patients included
Patients due for 5-year visit
Patients who had died
Lost to followup
Unable to attend 5-year visit
Patients who completed 5-year followup
* THA ⫽ total hip arthroplasty; BMI ⫽ body mass index.
between obese and nonobese patients who underwent revision THA.
Study design and patient population. We undertook a
prospective etiologic cohort study including all consecutive patients who underwent a revision THA at the university orthopedic department of the only public hospital
for the urban and surrounding rural population between
March 26, 1996 and July 31, 2006. Overall, 300 –350 primary and 25–30 revision THAs were done annually. Revisions were performed by senior orthopedic surgeons. We
excluded re-revisions from this study.
Study followup extended through October 31, 2006. For
those patients who underwent bilateral revisions during
the study period (n ⫽ 9), only the first revision THA was
included in order to allow for an analysis on the patient
level. A total of 205 patients were eligible. One patient was
excluded due to missing weight and height information,
leaving 204 patients (Table 1). All patients received antibiotic and thrombosis prophylaxis, and the procedures
were performed in ultraclean air laminar flow operating
rooms using hooded gowns. Gentamicin-loaded bone cement was used in cases with cemented implants.
Exposure and outcome variables. The exposure (etiologic factor) of interest was obesity defined as a BMI ⱖ30
kg/m2, in keeping with previous studies (12,13,30,32,34).
The association between BMI and the primary outcome
was also examined using 4 BMI categories (⬍25, 25–29.9,
30 –34.9, and ⱖ35).
The primary outcome was the incidence of adverse
events including the occurrence of ⱖ1 of the following
during the followup period: surgical site infection (prosthetic joint and/or superficial infection), dislocation (first
event), or re-revision for any cause. Prosthetic joint infection was diagnosed according to the criteria by Zimmerli et
al (35), and internationally recognized criteria (12) were
used for the inclusion of superficial infections.
Secondary outcomes were functional status, pain, and
patient satisfaction (all continuous variables) 5 years after
revision surgery. The Harris Hip Score (HHS; a physicianassessed, hip-specific clinical score evaluating the do-
mains of pain, function, deformity, and motion) (36) was
used to measure functional status. Scores range from 0
(worst) to 100 (best). The pain item of the HHS, consisting
of a 6-grade response scale (none, slight/occasional, mild,
moderate, marked, serious limitation/totally disabling
pain) and rated numerically from 0 to 44 (no pain ⫽ 44),
was used to define the pain outcome. The HHS is the most
widely used physician-assessed hip score in orthopedic
surgery (37,38). The total score and the pain subscore have
shown high reliability and validity (38 – 40). Patient satisfaction was measured using a 0 –10 visual analog scale,
where 10 ⫽ best.
In the estimation of the association between obesity and
the primary (and secondary) outcomes, the following potential confounders were assessed preoperatively: 1) age;
2) sex; 3) indication for revision defined as a 7-category
variable (aseptic loosening of cup, stem, or both; septic
loosening; recurrent dislocation; periprosthetic fracture;
technical error) as well as dichotomized variable (aseptic
loosening versus all other indications for revision); and 4)
surgery of the index hip prior to primary THA.
The following clinical scores were also preoperatively
assessed: the Merle d’Aubigné score, the Charnley classification grade, and the American Society of Anesthesiologists (ASA) score. The Merle d’Aubigné score (41) is a
hip-specific, physician-assessed clinical score evaluating
pain, function, and motion on a scale from 0 to 6 (best,
total score 18). The score has been used by orthopedic
surgeons to evaluate hip arthroplasties for more than 50
years, and it highly correlates with the HHS (Spearman’s
correlation coefficient 0.81– 0.82) (42,43). The Charnley
classification (44) comprises 3 grades: 1 hip affected and
the other normal (grade A), both hips affected (grade B),
and multiple-joint disease or other disabilities leading to
difficulties in ambulation (grade C). The ASA score is
obtained from the anesthesia report and evaluated as a
binary variable (1–2 versus 3– 4). It is a physical status
classification system aimed at grading the patient in relation to his physical preoperative status. The ASA 6-point
scale ranges from a healthy patient to a patient with an
extreme systemic disorder that is an imminent threat to
The Merle d’Aubigné score was used preoperatively
from March 1996 to June 2003. Complete score information was available for 30 (76.9%) of 39 obese patients and
for 88 (76.5%) of 115 nonobese patients operated on during that time period. Four patients had a missing ASA
The following information related to the revision surgery was assessed: 1) surgical approach without or with
(yes/no) use of trochanteric/proximal-femoral osteotomy
indicated in cases where greater femoral and/or acetabular
exposure was needed; 2) use of an acetabular ring in case
of insufficient acetabular bone (yes/no); 3) femoral head
size in millimeters; 4) cementing of stem and/or cup (yes/
no); and 5) operation time in minutes.
Data collection. Patient weight and height were obtained at the preoperative entrance examination, just before surgery. Information about the potential confounding
Lübbeke et al
Table 2. Distribution of baseline characteristics among obese and nonobese patients*
Age at operation, mean ⫾ SD years
Age, years
Reason for revision
Aseptic loosening total
Stem loosening
Cup loosening
Septic loosening
Recurrent dislocation
Periprosthetic fracture
Technical error
Merle d’Aubigné score, mean ⫾ SD‡
ASA score
Surgery prior to primary THA
Charnley classification
Hip contralateral
Affected unoperated
BMI <30
(n ⴝ 152)
BMI >30
(n ⴝ 52)
88 (57.9)
64 (42.1)
72.5 ⫾ 11.8
26 (50.0)
26 (50.0)
68.7 ⫾ 9.9
8 (5.2)
13 (8.6)
32 (21.1)
56 (36.8)
43 (28.3)
2 (3.8)
5 (9.6)
14 (26.9)
28 (53.9)
3 (5.8)
73 (48.0)
19 (12.5)
17 (11.2)
19 (12.5)
12 (7.9)
7 (4.6)
5 (3.3)
10.5 ⫾ 2.3
16 (30.8)
13 (25.0)
2 (3.8)
7 (13.5)
7 (13.5)
3 (5.8)
4 (7.6)
10.1 ⫾ 2.2
98 (64.5)
51 (33.6)
3 (1.9)
8 (5.3)
22 (42.3)
29 (55.8)
1 (1.9)
3 (5.8)
60 (39.5)
52 (34.2)
40 (26.3)
6 (11.5)
18 (34.6)
28 (53.9)
74 (48.7)
12 (7.9)
66 (43.4)
22 (42.3)
5 (9.6)
25 (48.1)
(95% CI)
Mean difference
(95% CI)†
1.2 (0.9, 1.7)
3.7 (0.1, 7.4)
0.4 (⫺0.6, 1.3)
1.7 (1.2, 2.3)
2.0 (1.4, 3.0)§
* Values are the number (percentage) unless indicated otherwise. BMI ⫽ body mass index; RR ⫽ relative risk; 95% CI ⫽ 95% confidence interval;
ASA ⫽ American Society of Anesthesiologists; THA ⫽ total hip arthroplasty.
† F or continuous variables.
‡ Used preoperatively from March 1996 to June 2003. Complete score information was available for 30 (77%) of 39 obese patients and 88 (77%) of 115
nonobese patients operated on during that time period.
§ Charnley classification grade C compared with grade A and B combined.
variables and the surgical intervention was systematically
documented by the operating surgeon on specifically designed data collection forms. The data were checked by a
trained medical secretary and 1 of the investigators (AL).
We retrieved information regarding primary outcome
events from each patient. We contacted all participants
who were 5 years postoperative for a followup visit that
included a clinical and radiologic examination. Information about the occurrence of the primary outcome events
since the intervention, which were not treated at our institution, was obtained either during the followup visit or,
for all those who were unable to join the followup visit, by
phone. Followup examinations were completed by 2
trained physicians who had not performed the operations.
Statistical analysis. The distribution of preoperative
baseline characteristics (potential confounders) and technique- and implant-related variables was examined for
obese and nonobese patients. To assess the association
between obesity and the primary outcome, we calculated
person-times from the date of operation until the first
occurrence of any of the above defined events, death, end
of the study (October 31, 2006), or loss to followup. Then
we estimated the crude incidence rate and crude incidence
rate ratio (IRR) with their 95% confidence intervals (95%
CIs). We repeated the analyses after stratification for age,
sex, ASA score, Charnley classification grade, and indication for revision (dichotomized) to identify possible confounding or effect modification using 2 BMI groups, with
the nonobese group as the reference group. Moreover, we
employed Cox proportional hazards analysis and presented adjusted hazard ratios (HRs). The proportional hazards assumption was checked by examining graphs of the
log minus log survival functions. The analyses above were
performed for any first primary outcome event, and then
repeated for the separate events if data allowed for it. Due
to the small numbers of primary outcome events, we adjusted only for the most important confounders, which
were ASA score for surgical site infection, and age and
ASA score for dislocation. No adjustment was made for the
outcome re-revision as only 8 patients had this event.
Additionally, incidence rates and IRRs for the first primary
Effect of Obesity on Revision THA
Table 3. Incidence rates for each of the adverse events across obese and nonobese
Complication (1 event)
Incidence rate†
Surgical site infection
Incidence rate†
Incidence rate†
Incidence rate†
BMI <30
(n ⴝ 152)
BMI >30
(n ⴝ 52)
Unadjusted IRR
(95% CI)
Adjusted HR
(95% CI)
4.7 (2.3, 9.6)
4.0 (1.8, 8.9)‡
4.6 (1.3, 16.4)
4.1 (1.1, 15.0)§
3.1 (1.3, 7.5)
3.5 (1.3, 9.3)¶
2.8 (0.7, 11.1)
* BMI ⫽ body mass index; IRR ⫽ incidence rate ratio; 95% CI ⫽ 95% confidence interval; HR ⫽ hazard
† Cases/100 person-years.
‡ Complication (1 event of any primary outcome) adjusted for age, sex, and American Society of
Anesthesiologists (ASA) score.
§ Surgical site infection (including superficial and deep infection) adjusted for ASA score.
¶ Dislocation adjusted for age and ASA score using Cox proportional hazards models.
outcome event were assessed across the 4 BMI categories
(⬍25, 25–29.9, 30 –34.9, and ⱖ35) with the normal weight
category (⬍25) as the reference group. We used Cox proportional hazards analysis to adjust for age, sex, and ASA
score. The Kaplan-Meier approach was employed to estimate the one minus survival function (cumulative incidence function).
To assess the association between obesity and the secondary outcomes, we calculated mean scores (with SDs)
and the (crude) mean differences with 95% CIs for obese
and nonobese patients using the unpaired Student’s t-test.
We repeated the analyses after stratification for age, sex,
Charnley classification grade, ASA score, and indication
for revision. Multivariable linear modeling was used to
adjust the effect of BMI on all 3 secondary outcomes for
age, sex, preoperative function and pain, ASA score, and
Charnley classification grade.
Among the 204 patients, 114 were women and 90 were
men, with a mean age of 71.6 years (range 32–94 years) and
a mean BMI of 26.7 (range 15– 44). Twenty-five percent
(n ⫽ 52) of the revisions were performed in patients with
a BMI ⱖ30. Table 2 presents the distribution of the baseline characteristics (potential confounders) across obese
and nonobese patients. The 2 groups mainly differed with
respect to age, ASA score, Charnley classification grade,
and indication for revision. Obese participants were
younger, more often classified as Charnley grade C, and
had higher ASA scores. Moreover, they were revised for
aseptic loosening less often overall (less loosening of the
cup or of both components, more stem loosening), but
more often for recurrent dislocation or technical error.
In obese patients the revision was performed, on average, 92 months after the primary hip THA, compared with
125 months in nonobese patients (mean difference 33
months, 95% CI 9, 58). The 2 groups did not significantly
differ with respect to the use of osteotomy. A trochanteric
or proximal femoral osteotomy was performed in 31 (60%)
obese patients and 79 (52%) nonobese patients. In the
obese group, an acetabular ring was used in 17 (43%) of
the 40 revisions involving a cup replacement as compared
with 89 (66%) of 134 cup replacements in the nonobese
group. In the large majority of patients, a 28-mm head was
chosen, except for 3 cases from each group with a 22-mm
or a 32-mm head. A cemented cup was inserted in 67% of
obese patients versus 80% of nonobese patients, and a
cemented stem in 83% versus 74%. The groups did not
differ with respect to operation time (209 versus 210 minutes).
Primary outcomes. The followup period for the primary
outcome ranged from 3 to 74 months. During followup, 3
(5.8%) of 52 obese patients and 22 (14.5%) of 152 nonobese patients had died, and 4 (7.7%) obese and 6 (3.9%)
nonobese patients were lost to followup.
Obese patients contributed a mean ⫾ SD of 33 ⫾ 25
person-months, and nonobese patients contributed a
mean ⫾ SD of 41 ⫾ 21 person-months. Overall, 20 complications occurred in 17 (33%) of 52 obese patients compared with 18 events in 13 (9%) of 152 nonobese patients.
Surgical site infections were reported in 6 (11.5%) obese
patients (3 superficial, 3 prosthetic joint) and 4 (2.6%)
Lübbeke et al
Table 4. Occurrence of first primary outcome event (surgical site infection, dislocation,
or re-revision) according to 4 BMI categories*
Incidence rate†
Unadjusted IRR (95% CI)
Adjusted HR (95% CI)‡
(n ⴝ 83)
(n ⴝ 69)
(n ⴝ 41)
(n ⴝ 11)
1.0 (Ref.)
1.0 (Ref.)
1.9 (0.6, 5.8)
1.5 (0.5, 4.7)
5.8 (2.0, 16.4)
4.5 (1.4, 14.0)
10.0 (2.9, 34.7)
10.9 (2.9, 41.1)
* BMI ⫽ body mass index; IRR ⫽ incidence rate ratio; HR ⫽ hazard ratio; 95% CI ⫽ 95% confidence
† Cases/100 person-years.
‡ Adjusted for age, sex, and American Society of Anesthesiologists score using Cox proportional hazards
nonobese patients (1 superficial, 3 prosthetic joint). The
crude incidence rate was 4.6 times higher in obese patients
(Table 3). After adjustment for ASA score, the adjusted HR
was 4.1 (95% CI 1.1, 15.0). After stratification for sex, we
observed a higher incidence rate of infection in obese
versus nonobese women (IRR 15.5, 95% CI 1.7, 138.8) but
no significant increase in obese versus nonobese men (IRR
2.0, 95% CI 0.3, 12.2). Dislocation was observed in 10
(19.2%) obese patients and 10 (6.6%) nonobese patients.
The crude incidence rate was 3.1 times higher in obese
individuals. After adjustment for age and ASA score, the
adjusted HR was 3.5 (95% CI 1.3, 9.3). Eight re-revisions
were undertaken, with 4 re-revisions in each group (7.7%
versus 2.6%). In each group, 2 re-revisions were performed
for septic loosening; 1 for recurrent dislocation and 1 for
early aseptic loosening of the cup. The crude incidence
rate of re-revision for any cause was 2.8 times higher in
obese patients (95% CI 0.7, 11.1). Loss of fixation of the
trochanteric osteotomy was observed in 5 (17.2%) obese
patients and 5 (9.3%) nonobese patients.
The incidence rate for the occurrence of ⱖ1 adverse
event increased with rising BMI (Table 4 and Figure 1).
This increase was small between normal and overweight
patients (adjusted HR 1.5), but it became significantly
greater in the group with a BMI 30 –34.9 (adjusted HR 4.5)
and was most evident in the group with a BMI ⱖ35 (adjusted HR 10.9), although the width of the 95% CI increased due to the low patient number in this latter group.
Adjustment was performed for age, sex, and ASA score.
Further adjustment for indication for revision and Charnley classification grade did not substantially change the
Secondary outcomes. Five years after revision, 31 obese
and 79 nonobese patients were due for followup. Among
the obese group, 2 (6.5%) patients had died, 3 (9.7%) were
lost to followup, and 2 (6.5%) were unable to attend. Of
the nonobese patients, 13 (16.5%) had died, 5 (6.3%) were
lost to followup, and 5 (6.3%) were unable to attend. Of
those still alive, 24 (82.8%) obese patients and 56 (84.8%)
nonobese patients were seen at the 5-year visit. The
mean ⫾ SD time to followup was 57 ⫾ 8 months.
Five years postoperatively, obesity was associated with
moderately lower functional status (HHS) and a lower pain
subscore, which remained after adjustment for age, sex,
preoperative function and pain (Merle d’Aubigné score),
ASA score, and Charnley classification grade (Table 5).
The association with patient satisfaction was less evident,
after adjustment the 95% CI included 0.
The primary aim of this study was to determine whether
obesity was associated with a higher incidence of major
events in patients undergoing revision THA. We found
significantly more events, notably surgical site infections
and dislocations, in obese patients. Secondarily, we found
moderately lower results on the HHS but almost similar
satisfaction in obese patients 5 years postoperatively.
In comparison with primary THA, revision surgery is
associated with greater soft tissue damage and prolonged
Figure 1. Cumulative incidence (one minus survival function) of
first primary outcome event (surgical site infection, dislocation, or
re-revision) in normal weight (body mass index [BMI] ⬍25), overweight (BMI 25–29.9), obese (BMI 30 –34.9), and highly obese
(BMI ⱖ35) patients after revision total hip arthroplasty using the
Kaplan-Meier approach.
Effect of Obesity on Revision THA
Table 5. Harris hip score (HHS), pain, and patient satisfaction at 5 years for obese and nonobese patients*
BMI, mean ⴞ SD
HHS pain
Difference, mean (95% CI)
<30 (n ⴝ 56)
>30 (n ⴝ 24)
82.8 ⫾ 14.7
39.2 ⫾ 7.2
8.2 ⫾ 1.8
71.4 ⫾ 17.0
33.9 ⫾ 9.6
7.2 ⫾ 2.7
11.4 (3.9, 18.9)
5.3 (0.8, 9.7)
1.0 (⫺0.2, 2.3)
9.2 (2.0, 16.7)
5.0 (0.9, 9.1)
0.8 (⫺0.3, 1.9)
8.9 (1.9, 15.9)
5.4 (1.1, 9.8)
1.1 (⫺0.1, 2.3)
* Values are the mean ⫾ SD unless otherwise indicated. BMI ⫽ body mass index; 95% CI ⫽ 95% confidence interval.
† Adjusted for age, sex, and Charnley classification grade (all 80 patients included in analysis).
‡ Adjusted for age at operation, sex, preoperative Merle d’Aubigné score, American Society of Anesthesiologists (ASA) score, and Charnley
classification grade. Due to missing values on preoperative Merle d’Aubigné score and ASA score, only 66 patients could be included for adjustment.
operation time, which may explain the increased incidence of superficial and deep infections after revision.
Larger soft tissue dissection and subsequent increased
muscle weakness in revision THA might be one of the
responsible factors for higher dislocation rates (45). In
turn, obesity has been associated with higher rates of
wound healing complications (46) and higher morbidity.
Furthermore, in obese patients the intervention can be
more technically challenging with respect to exposure,
implant positioning, and soft tissue closure (47).
Literature about the influence of obesity on the occurrence of adverse events after revision THA is sparse. Most
studies have reported on small patient groups and short
followup periods. Perka et al (31), in a retrospective study
including 229 patients of whom 31 had a BMI ⱖ30, found
no increase in perioperative morbidity and mortality
within 90 days. Another study (12) evaluated the risk of
surgical site infection after revision according to 3 BMI
categories. The authors did not observe an increase in
infection in obese patients during the study followup,
which was limited to the in-hospital postoperative period.
In contrast, a recent matched cohort study (30) reported
a much higher risk of dislocation (relative risk 6.3) in
morbidly obese patients as compared with a group of normal-weight and overweight patients 12 to 28 months after
revision THA. The mean age of their patients was 57 years,
compared with 72 years in our study. All patients were
operated upon by 1 experienced surgeon. The even higher
relative risk for dislocation in obese patients in their study
might be due to the low dislocation rate (3%) in their
young, nonobese patients.
In a previous study evaluating the effect of obesity on
complications after primary THA, we observed a 4-times
higher rate of infection similar to our current findings. The
only difference is that in the present study, we included
both superficial and prosthetic infections (11). However,
the increase in dislocation due to obesity was less important after primary THA in that study than it was in this
study (2 times versus 3 times higher).
Our findings are also in accordance with several other
studies reporting on increased postoperative complications in obese patients after primary THA (7,8,12,13). Two
of these studies found higher rates of postoperative infections (8,12). Stickles et al (13) evaluated 1-year orthopedic
complication rates according to 5 BMI categories (⬍25,
25–29, 30 –34, 35–39, and ⱖ40) using univariate analyses,
and they found a significant increase with rising BMI,
similar to what we observed in our data. A few studies
reported similar short-term (orthopedic) complication
rates (14 –18), but their numbers of patients, and as a
consequence their numbers of adverse events, were small.
Literature about pain and function after revision THA is
lacking. Lower functional results (on the HHS score) in
obese patients undergoing revision THA have been reported in 2 studies at 3 and 5 years postoperative (32,33).
In contrast to the present study, those analyses were unadjusted. Davis et al (48) analyzed predictors of pain and
functional outcomes 2 years after revision THA using the
Western Ontario and McMaster Universities Osteoarthritis
Index, and they emphasized the importance of preoperative pain and function for the 2-year results. However, they
did not include BMI among their predictors.
Previous studies have reported that obesity was associated with greater pain and disability in patients with hip
or knee osteoarthritis (49,50). However, we found similar
preoperative Merle d’Aubigné scores (10.5 in nonobese
versus 10.1 in obese patients) together with significant
differences in Charnley classification grades between the 2
groups. Part of the explanation for this could be that the
function domain, which we expect to mainly be related to
disability, counts only for one-third of the total Merle
d’Aubigné score. An additional subscore analysis of our
data revealed that the difference of 0.4 points on the preoperative Merle d’Aubigné score between obese and nonobese patients was mostly due to lower function subscores
in the obese group. With respect to the pain issue, we are
unable to provide a clear reason why obese and nonobese
patients did not differ at baseline in our study.
This prospective, hospital-based study compared the
occurrence of several main adverse events in addition to
pain, functional outcome, and patient satisfaction 5 years
postoperatively in obese and nonobese patients undergoing first revision THA. To our knowledge, the followup
period was longer than in any previous study. Analyses
were performed for 2 and 4 BMI categories. We used incidence rates and Cox proportional hazards analysis to account for patient differences in length of followup and
censoring, and to adjust for baseline differences (confounding) across BMI categories. Data collection and clinical followup were standardized, and the clinical assessment was performed by 2 independent surgeons in order
to avoid observer bias.
The study has several weaknesses. First, it was limited
by the relatively small number of adverse events resulting
in large confidence intervals. For the same reason, we were
unable to adjust for all potentially confounding factors.
Lübbeke et al
However, adjustment for several confounders was made
for the combined complications, and for the complications
infection and dislocation alone we adjusted for the most
important confounders. Second, obese and nonobese patients differed by several baseline characteristics, which
could be due to differences in the adverse events following
primary THA and/or differential selection at the time of
indication for primary or revision arthroplasty. Because 2
different clinical scores evaluating pain, function, and mobility were used at baseline and at followup, we were
unable to analyze score differences. No information on
intraoperative bone quality was available, but reports have
shown that obese subjects tend to have greater bone mineral density and a lower risk of hip fractures (51–53). In
addition, the need for an acetabular ring indicating insufficient acetabular bone stock was higher in the nonobese
group, and severity of revision based on bone stock loss
was not found to be significantly related to pain and function in the study by Davis et al. Finally, our study was
conducted at 1 large academic center; however, baseline
characteristics and indications for revisions did not substantially differ from descriptions of other hospital- or
community-based revision cohorts in the literature
(30,54 –56). Further studies including a larger number of
patients are needed to assess external validity and to evaluate the extent to which different techniques and implants
can influence the results.
Revision THA is a technically-challenging intervention,
particularly in obese patients, probably because of more
difficult anatomical conditions. Our results revealed that
obesity was associated with higher event rates; notably,
surgical site infection and dislocation. Furthermore, we
found moderately lower HHS with higher levels of pain 5
years postoperative. Surgeons, patients, and referring physicians should be aware of an increased risk of adverse
events in this patient group. Further studies are necessary
to evaluate whether changes in medical preparation, surgical technique, and implant choice can help reduce the
adverse event rate in obese patients undergoing revision
The authors would like to thank Richard Stern, MD for his
helpful comments.
Dr. Lübbeke had full access to all of the data in the study and
takes responsibility for the integrity of the data and the accuracy
of the data analysis.
Study design. Lübbeke, Moons, Hoffmeyer.
Acquisition of data. Lübbeke, Garavaglia.
Analysis and interpretation of data. Lübbeke, Moons.
Manuscript preparation. Lübbeke, Moons.
Statistical analysis. Lübbeke, Moons.
1. Felson DT. An update on the pathogenesis and epidemiology
of osteoarthritis. Radiol Clin North Am 2004;42:1–9.
2. Flugsrud GB, Nordsletten L, Espehaug B, Havelin LI, Engeland A, Meyer HE. The impact of body mass index on later
total hip arthroplasty for primary osteoarthritis: a cohort
study in 1.2 million persons. Arthritis Rheum 2006;54:802–7.
Karlson EW, Mandl LA, Aweh GN, Sangha O, Liang MH,
Grodstein F. Total hip replacement due to osteoarthritis: the
importance of age, obesity, and other modifiable risk factors.
Am J Med 2003;114:93– 8.
Lievense AM, Bierma-Zeinstra SM, Verhagen AP, van Baar
ME, Verhaar JA, Koes BW. Influence of obesity on the development of osteoarthritis of the hip: a systematic review. Rheumatology (Oxford) 2002;41:1155– 62.
Oliveria SA, Felson DT, Cirillo PA, Reed JI, Walker AM. Body
weight, body mass index, and incident symptomatic osteoarthritis of the hand, hip, and knee. Epidemiology 1999;10:
161– 6.
Wendelboe AM, Hegmann KT, Biggs JJ, Cox CM, Portmann AJ,
Gildea JH, et al. Relationships between body mass indices and
surgical replacements of knee and hip joints. Am J Prev Med
2003;25:290 –5.
Jain NB, Guller U, Pietrobon R, Bond TK, Higgins LD. Comorbidities increase complication rates in patients having arthroplasty. Clin Orthop Relat Res 2005;435:232– 8.
Namba RS, Paxton L, Fithian DC, Stone ML. Obesity and
perioperative morbidity in total hip and total knee arthroplasty patients. J Arthroplasty 2005;20:46 –50.
Sadr Azodi O, Bellocco R, Eriksson K, Adami J. The impact of
tobacco use and body mass index on the length of stay in
hospital and the risk of postoperative complications among
patients undergoing total hip replacement. J Bone Joint Surg
Br 2006;88:1316 –20.
Eveillard M, Mertl P, Canarelli B, Lavenne J, Fave MH, Eb F,
et al. Risk of deep infection in first-intention total hip
replacement: evaluation concerning a continuous series of
790 cases. Presse Med 2001;30:1868 –75. In French.
Lubbeke A, Stern R, Garavaglia G, Zurcher L, Hoffmeyer P.
Differences in outcomes of obese women and men undergoing
primary total hip arthroplasty. Arthritis Rheum 2007;57:327–
Ridgeway S, Wilson J, Charlet A, Kafatos G, Pearson A, Coello
R. Infection of the surgical site after arthroplasty of the hip.
J Bone Joint Surg Br 2005;87:844 –50.
Stickles B, Phillips L, Brox WT, Owens B, Lanzer WL. Defining the relationship between obesity and total joint arthroplasty. Obes Res 2001;9:219 –23.
Ibrahim T, Hobson S, Beiri A, Esler CN. No influence of body
mass index on early outcome following total hip arthroplasty.
Int Orthop 2005;29:359 – 61.
Lehman DE, Capello WN, Feinberg JR. Total hip arthroplasty
without cement in obese patients: a minimum 2-year clinical
and radiographic followup study. J Bone Joint Surg Am 1994;
76:854 – 62.
McLaughlin JR, Lee KR. The outcome of total hip replacement
in obese and nonobese patients at 10 to 18 years. J Bone Joint
Surg Br 2006;88:1286 –92.
Moran M, Walmsley P, Gray A, Brenkel IJ. Does body mass
index affect the early outcome of primary total hip arthroplasty? J Arthroplasty 2005;20:866 –9.
Soballe K, Christensen F, Luxhoj T. Hip replacement in obese
patients. Acta Orthop Scand 1987;58:223–5.
Espehaug B, Havelin LI, Engesaeter LB, Langeland N, Vollset
SE. Patient-related risk factors for early revision of total hip
replacements: a population register-based case– control study
of 674 revised hips. Acta Orthop Scand 1997;68:207–15.
McClung CD, Zahiri CA, Higa JK, Amstutz HC, Schmalzried
TP. Relationship between body mass index and activity in hip
or knee arthroplasty patients. J Orthop Res 2000;18:35–9.
Munger P, Roder C, Ackermann-Liebrich U, Busato A. Patient-related risk factors leading to aseptic stem loosening in
total hip arthroplasty: a case– control study of 5,035 patients.
Acta Orthop 2006;77:567–74.
Raut VV, Kay P, Siney PD, Wroblewski BM. Factors affecting
socket fixation after cemented revision. Int Orthop 1997;21:
83– 6.
Surin VV, Sundholm K. Survival of patients and prostheses
Effect of Obesity on Revision THA
after total hip arthroplasty. Clin Orthop Relat Res 1983;177:
148 –53.
Chan CL, Villar RN. Obesity and quality of life after primary
hip arthroplasty. J Bone Joint Surg Br 1996;78:78 – 81.
Lie SA, Havelin LI, Furnes ON, Engesaeter LB, Vollset SE.
Failure rates for 4,762 revision total hip arthroplasties in the
Norwegian Arthroplasty Register. J Bone Joint Surg Br 2004;
86:504 –9.
Mahomed N, Katz JN. Revision total hip arthroplasty: indications and outcomes [review]. Arthritis Rheum 1996;39:1939 –
Mahomed NN, Barrett JA, Katz JN, Phillips CB, Losina E, Lew
RA, et al. Rates and outcomes of primary and revision total
hip replacement in the United States Medicare population.
J Bone Joint Surg Am 2003;85A:27–32.
Pellicci PM, Wilson PD Jr, Sledge CB, Salvati EA, Ranawat CS,
Poss R, et al. Long-term results of revision total hip
replacement: a followup report. J Bone Joint Surg Am 1985;
67:513– 6.
Saleh KJ, Celebrezze M, Kassim R, Dykes DC, Gioe TJ, Callaghan JJ, et al. Functional outcome after revision hip
arthroplasty: a meta-analysis. Clin Orthop Relat Res 2003;416:
254 – 64.
Kim Y, Morshed S, Joseph T, Bozic K, Ries MD. Clinical
impact of obesity on stability following revision total hip
arthroplasty. Clin Orthop Relat Res 2006;453:142– 6.
Perka C, Labs K, Muschik M, Buttgereit F. The influence of
obesity on perioperative morbidity and mortality in revision
total hip arthroplasty. Arch Orthop Trauma Surg 2000;120:
Katz JN, Phillips CB, Baron JA, Fossel AH, Mahomed NN,
Barrett J, et al. Association of hospital and surgeon volume of
total hip replacement with functional status and satisfaction 3
years following surgery. Arthritis Rheum 2003;48:560 – 8.
Lubbeke A, Katz JN, Perneger TV, Hoffmeyer P. Primary and
revision hip arthroplasty: 5-year outcomes and influence of
age and comorbidity. J Rheumatol 2007;34:394 – 400.
World Health Organization. Obesity: preventing and managing the global epidemic. Report of a WHO consultation.
Geneva: WHO; 1997.
Zimmerli W, Trampuz A, Ochsner PE. Prosthetic-joint infections. N Engl J Med 2004;351:1645–54.
Harris WH. Traumatic arthritis of the hip after dislocation and
acetabular fractures: treatment by mold arthroplasty. An endresult study using a new method of result evaluation. J Bone
Joint Surg Am 1969;51:737–55.
Mahomed NN, Arndt DC, McGrory BJ, Harris WH. The Harris
hip score: comparison of patient self-report with surgeon
assessment. J Arthroplasty 2001;16:575– 80.
Soderman P, Malchau H. Is the Harris hip score system useful
to study the outcome of total hip replacement? Clin Orthop
Relat Res 2001;384:189 –97.
McGrory BJ, Freiberg AA, Shinar AA, Harris WH. Correlation
of measured range of hip motion following total hip arthroplasty and responses to a questionnaire. J Arthroplasty 1996;
McGrory BJ, Harris WH. Can the Western Ontario and Mc-
Master Universities (WOMAC) osteoarthritis index be used to
evaluate different hip joints in the same patient? J Arthroplasty 1996;11:841– 4.
Merle D’Aubigne R. Functional results of arthroplasty of the
hip. Acta Orthop Belg 1953;19:81–103.
Bryant MJ, Kernohan WG, Nixon JR, Mollan RA. A statistical
analysis of hip scores. J Bone Joint Surg Br 1993;75:705–9.
Ovre S, Sandvik L, Madsen JE, Roise O. Comparison of distribution, agreement and correlation between the original and
modified Merle d’Aubigné-Postel Score and the Harris hip
score after acetabular fracture treatment: moderate agreement,
high ceiling effect and excellent correlation in 450 patients.
Acta Orthop 2005;76:796 – 802.
Charnley J. Numerical grading of clinical results. In: Low
friction arthroplasty of the hip: theory and practice. Berlin:
Springer-Verlag; 1979. p. 20 – 4.
Alberton GM, High WA, Morrey BF. Dislocation after revision
total hip arthroplasty: an analysis of risk factors and treatment
options. J Bone Joint Surg Am 2002;84-A:1788 –92.
Thomas EJ, Goldman L, Mangione CM, Marcantonio ER, Cook
EF, Ludwig L, et al. Body mass index as a correlate of postoperative complications and resource utilization. Am J Med
1997;102:277– 83.
Della Valle CJ. Total hip arthroplasty in obese patients. In:
Lieberman JR, Berry DJ, editors. Advanced reconstruction:
hip. Rosemont, IL: American Academy of Orthopedic
Surgeons; 2006.
Davis AM, Agnidis Z, Badley E, Kiss A, Waddell JP, Gross AE.
Predictors of functional outcome 2 years following revision
hip arthroplasty. J Bone Joint Surg Am 2006;88:685–91.
Cimmino MA, Sarzi-Puttini P, Scarpa R, Caporali R, Parazzini
F, Zaninelli A, et al. Clinical presentation of osteoarthritis in
general practice: determinants of pain in Italian patients in
the AMICA study. Semin Arthritis Rheum 2005;35:17–23.
Marks R. Obesity profiles with knee osteoarthritis: correlation
with pain, disability, disease progression. Obesity (Silver
Spring) 2007;15:1867–74.
Felson DT, Zhang Y, Hannan MT, Anderson JJ. Effects of
weight and body mass index on bone mineral density in men
and women: the Framingham study. J Bone Miner Res 1993;
Gruen T. A simple assessment of bone quality prior to hip
arthroplasty: cortical index revisited. Acta Orthop Belg
1997;63 Suppl 1:20 –7.
Langlois JA, Mussolino ME, Visser M, Looker AC, Harris T,
Madans J. Weight loss from maximum body weight among
middle-aged and older white women and the risk of hip
fracture: the NHANES I epidemiologic followup study. Osteoporos Int 2001;12:763– 8.
Khatod M, Barber T, Paxton E, Namba R, Fithian D. An analysis of the risk of hip dislocation with a contemporary total
joint registry. Clin Orthop Relat Res 2006;447:19 –23.
Lachiewicz PF, Soileau ES. Changing indications for revision
total hip arthroplasty. J Surg Orthop Adv 2005;14:82– 4.
Malchau H, Herberts P, Ahnfelt L. Prognosis of total hip
replacement in Sweden: followup of 92,675 operations performed 1978 –1990. Acta Orthop Scand 1993;64:497–506.
Без категории
Размер файла
131 Кб
outcomes, hip, tota, patients, obesp, nonobese, revision, arthroplasty, undergoing
Пожаловаться на содержимое документа