Abstract
Background: Anterolateral acetabular bone deficiency
is one of the technical problems associated with total hip arthroplasty
in patients with developmental hip dysplasia. The purpose of this
study was to evaluate the results of one method of acetabular reconstruction
for hip dysplasia—placement of an uncemented socket in
conjunction with a bulk femoral head autograft.
Methods: Forty-four hips in thirty-five patients
(twenty-nine female and six male; average age, thirty-nine years)
with developmental hip dysplasia were treated with primary total
hip arthroplasty with use of an uncemented porous-coated titanium
cup fixed with screws and an autogenous bulk femoral head graft.
The patients were followed clinically in a prospective fashion for
five to 12.3 years (mean, 7.5 years), and radiographs were analyzed
retrospectively.
Results: Four acetabular components were revised:
two, because of severe polyethylene wear and osteolysis; one, because
of aseptic loosening; and one, because of fracture of the acetabular
shell. The mean Harris hip score for the unrevised hips improved
from 51 points preoperatively to 91 points postoperatively. No unrevised
socket had definite radiographic evidence of loosening. Forty-three
of the forty-four hips had no radiographic evidence of resorption
of the graft or had radiographic evidence of resorption limited
to the nonstressed area of the graft lateral to the edge of the
cup.
Conclusions: This method of reconstruction provided
reliable acetabular fixation and appeared to restore acetabular
bone stock in patients with developmental hip dysplasia. We use
this technique for patients with moderate anterolateral acetabular
bone deficiency requiring total hip arthroplasty.
When total hip arthroplasty is required in a patient with
developmental dysplasia of the hip, anterolateral bone deficiency often
precludes conventional methods of acetabular reconstruction. Various
methods of reconstruction to obtain coverage and stability of the
acetabular component have been described, including a small cup
placed in an anatomical location or a superior position1-3, medial displacement of the cup
by perforation or fracture of the medial wall of the acetabulum4,5, and augmentation of bone stock
with lateral bulk bone-grafting of the pelvis in conjunction with
implantation of a cemented or uncemented cup6-13.
Augmentation of bone stock with bulk bone-grafting has some advantages:
it allows placement of the cup in a more anatomical position, and
it provides support for the acetabular component. On the other hand,
there is a risk that bulk bone grafts may collapse or be resorbed
with time. Implantation of a cemented cup in conjunction with a
femoral head autograft has been reported to have favorable early
results but poorer mid-term and long-term results14-17.
In the last decade, a number of reports have described favorable
short-term results of arthroplasty with an uncemented acetabular
component combined with a bulk femoral head autograft6,12,18,19, but there is little information
on the mid-term to long-term results of this type of acetabular
reconstruction. Specifically, little is known about the durability
of uncemented socket fixation in conjunction with a bulk acetabular
autograft or about the fate of the bulk autograft in this setting.
The purpose of this study was to review the results at a minimum
of five years after total hip arthroplasty with an uncemented socket
used in conjunction with a bulk femoral head autograft in patients with
acetabular bone deficiency due to developmental dysplasia.
The study group comprised thirty-five consecutive patients (forty-four
hips) in whom degenerative joint disease secondary to developmental
hip dysplasia had been treated, prior to 1993, with primary total
hip arthroplasty. During the arthroplasty, an uncemented titanium
porous-coated acetabular component was fixed to the pelvis with
screws and superior segmental deficiencies of the acetabular bone
were reconstructed with use of the patient’s ipsilateral
femoral head as an autograft. The operative approach was anterolateral
in twenty hips, transtrochanteric in twelve, and posterior in twelve.
The bone graft was fixed to the pelvis with screws prior to the
final reaming. As a general rule, bulk bone graft was not used in patients
with developmental dysplasia unless at least 1.5 cm of the socket
would have been uncovered with the cup in good position. During
the same time-period, 334 hips with a diagnosis of dysplasia were
treated with other methods of total hip arthroplasty.
Twenty-nine of the thirty-five patients were female. The average
age at the time of the index arthroplasty was thirty-nine years
(range, twelve to sixty-seven years). Sixteen hips had been treated
previously with one or more surgical procedures.
On the acetabular side, a Harris-Galante-I cup (Zimmer, Warsaw,
Indiana) was used in fifteen hips; a Harris-Galante-II cup (Zimmer),
in nine; an Osteonics PSL cup (Howmedica Osteonics, Allendale, New
Jersey), in fourteen; an Osteonics Omnifit Spherical cup (Howmedica
Osteonics), in five; and an Osteonics Dual Geometry cup (Howmedica
Osteonics) fixed with screws, in one. The median cup diameter was
48 mm (range, 42 to 58 mm). Forty-one femoral components were uncemented,
and three were cemented.
All patients were asked to return for a clinical examination and
radiographs at one, two, five, and ten-year intervals, or more frequently,
after the surgery. Patients who could not return for an examination
answered a detailed standardized letter or telephone questionnaire
and sent radiographs. For patients who subsequently underwent revision,
the immediate prerevision clinical data were used for analysis.
The preoperative, immediate postoperative, and most recent follow-up
radiographs were assessed. When a patient had undergone revision
of the acetabular component, the radiographs made just prior to
the revision procedure were used for analysis. Preoperative radiographs
were assessed for the degree of acetabular dysplasia by measuring
four indices of dysplasia: the level of dislocation as classified
by Crowe et al.20, the center-edge
angle of Wiberg21, the acetabular
angle22, and the acetabular roof
(Tönnis) angle23.
The percentage of coverage of the acetabular component by the
femoral head autograft was assessed on the immediate postoperative
radiographs. Graft coverage of the acetabular component was calculated
as a percentage of the porous-coated surface of the acetabular component
measured on the anteroposterior pelvic radiograph. The average coverage
of the acetabular component by the femoral head autograft was 28% (range,
9% to 98%). Five hips had between 0% and
15% cup coverage; twenty-five, between 16% and
30%; eleven, between 31% and 45%; and
three, >45%. On the most recent radiographs, union
of the graft to host bone was inferred by the disappearance of the
femoral head-host bone interface and, when visible, the appearance
of bridging trabeculae across this interface. Radiographs were assessed
for any change in the position of the acetabular component or migration
of the acetabular component, with use of the radiographic teardrop
and the interteardrop line as references. Radiolucent lines at the
bone-implant interface were recorded in the acetabular zones described
by DeLee and Charnley24. Inclination
of the acetabular component, measured as the angle subtended by
the face of the socket and the interteardrop line on anteroposterior
pelvic radiographs, averaged 43° (range, 20° to 57°) postoperatively.
The mean vertical distance of the center of hip rotation above the
interteardrop line was 40 mm preoperatively and 23 mm postoperatively.
Probable or definite acetabular loosening was defined as a change
in socket position, socket migration, screw fracture, or a complete
radiolucent line at the bone-implant interface of 2 mm in any zone.
Preoperative radiographs were available for forty-three of the forty-four
hips. According to the classification system of Crowe et al.20, twenty hips (47%) were
in Group I; twelve (28%), in Group II; nine (21%),
in Group III; and two (5%), in Group IV. Other preoperative
indices of acetabular dysplasia revealed an average center-edge
angle of -6° (range, -53° to 40°), an average Tönnis angle23 of 35° (range, 10° to 62°), and
an average acetabular angle of 53° (range, 36° to 67°).
Kaplan-Meier survival analysis25 was
performed with two different end points: revision of the acetabular
component for any reason, and revision of the acetabular component
because of aseptic loosening.
The mean duration of clinical
follow-up was 7.5 years (range, five to 12.3 years) and the mean
duration of radiographic follow-up was 7.4 years (range, 4.2 to
12.9 years), excluding one patient who had a revision at 3.5 years
and was included in all of the analyses. All patients who did not
have a revision (Figs. 1-A and 1-B) had at least five years of clinical
and radiographic follow-up, with the exception of one patient who
was doing well clinically at ten years but declined to have radiographs
made. The most recent radiographic follow-up for that patient was
performed at 4.2 years after the operation, at which time there were
no signs of failure. There were no deaths in the series.
Four acetabular components were revised, at 3.5, 6.0, 6.3, and 7.9
years following the index procedure. Two of these components were
revised because of severe polyethylene wear and osteolysis; one,
because of aseptic acetabular loosening; and one, because of a fracture
of the metal shell of the cup. In the two patients (thirty-four
and twenty-one years of age) who had the revision because of wear
and osteolysis, the cup was well fixed at the time of revision.
Both sockets had a 46-mm outside diameter matched with a 22-mm femoral
head. The patient with aseptic acetabular loosening had Crowe Group-I dysplasia,
with 11% of the acetabular component covered by the graft.
The patient with fracture of the cup had Crowe Group-III dysplasia,
with 97% of the cup covered by the graft. At revision,
the inferior part of the cup was fixed to bone but the superior
part was broken and loose and had migrated into the bone graft.
Three of the four sockets that were revised were replaced with another
uncemented hemispherical socket, and one hip (in the patient with
97% graft coverage) was treated with a reconstruction ring;
none of the four patients required additional structural grafts.
At revision, three of the four grafts were reported to be healed
to host bone; the status of the fourth was not commented upon by
the surgeon.
Clinical evaluation demonstrated a marked decrease in pain and
improvement in function following total hip replacement. The Harris
hip score for the unrevised hips improved from an average of 51
points (range, 29 to 81 points) preoperatively to an average of
91 points (range, 61 to 100 points) postoperatively. Thirty-seven
unrevised hips (93%) had been categorized as causing moderate
or severe pain preoperatively compared with only one unrevised hip
(3%) that caused moderate pain at the time of the latest
follow-up. The one patient with moderate pain (after 6.1 years of
follow-up) walked with no aids, had had severe preoperative pain,
and believed that he was much better postoperatively; he had a complete
radiolucent line of <1 mm at the socket-bone interface.
Seventeen patients (43% of the unrevised hips) required
a cane, crutch, or crutches preoperatively compared with only two
patients (5% of the unrevised hips) at the time of the
most recent follow-up.
At the time of the last radiographic follow-up, three unrevised cups
had a complete radiolucent line of £1 mm in width in all three
zones but no other signs of loosening. These cups were not considered
loose but may have had fibrous rather than bone ingrowth. One other
acetabular component, which had 88% coverage by the graft
on the anteroposterior radiograph, demonstrated a 10° change to
a more vertical position and fracture of one of the fixation screws
within the first year. However, the position of the component did
not change further with time and, at the most recent (10.4-year)
radiographic follow-up examination, the cup appeared well fixed
with no complete radiolucent line and no graft resorption. The remainder
of the sockets either had no radiolucent lines or had noncircumferential
lines in only one or two zones. No other socket showed evidence
of probable or definite loosening.
At the time of the last follow-up, all of the grafts appeared healed
to host bone. Resorption was categorized as lateral to the cup (in
unstressed areas) or over the cup (in a stressed area). Forty-three
(98%) of the forty-four grafts showed no evidence of resorption
(eight grafts) or resorption only lateral to the cup (thirty-five
grafts) (Fig. 1-B).
The resorption lateral to the cup typically represented rounding
off of the graft and was not extensive. Therefore, the femoral head
autografts appeared to provide continued coverage of the cup and
seemed to augment pelvic bone stock. One femoral head autograft
showed moderate resorption over the loaded area of the component.
This graft, which covered 33% of the cup, underwent resorption
over the lateral margin of the cup and involved about 10% of
the surface of the cup. The cup remained well fixed after 11.3 years
of follow-up.
At the time of the latest follow-up, forty of the forty-four
acetabular components had survived without revision for any reason.
According to Kaplan-Meier survival estimates, the ten-year rate
of survival without acetabular revision for any reason (wear, osteolysis,
or loosening) was 85% (95% confidence interval,
70% to 100%). With inclusion of the hip that failed
because of a broken socket as a failure due to loosening, forty-two
of the forty-four hips survived without revision for aseptic loosening.
The ten-year rate of survival without acetabular revision because
of aseptic loosening was 91% (95% confidence interval,
77% to 100%).
Complications included eight minimally displaced intraoperative
fractures of the proximal part of the femur during insertion of
the stem without cement. There were no superficial or deep infections.
There were no dislocations, but one patient had episodes of subluxation.
Another patient sustained a late periprosthetic fracture at the
tip of a well-fixed femoral component as a result of a motor-vehicle
accident eight years postoperatively. Three femoral components were
revised during the study period: one was well fixed but was revised because
femoral lysis was seen during an acetabular revision, one was loose
and was revised at the time of an acetabular revision, and one was
revised alone because of aseptic loosening.
Some anterolateral acetabular bone deficiency is present in most
patients with acetabular dysplasia. Managing this deficiency is
one of the technical problems that must be overcome when total hip
arthroplasty is used to treat developmental dysplasia. This study
demonstrated good mid-term results after use of an uncemented porous-coated
socket fixed with screws in conjunction with a bulk femoral head
autograft.
The bulk grafts in this series were used for bone deficiencies of
varying severity. The amount of the socket covered by the graft
as seen on the anteroposterior radiograph ranged from 9% to
98%. However, the anteroposterior radiograph provides only
a two-dimensional representation of a three-dimensional reconstruction.
In some cases, the anteroposterior pelvic radiograph leads to an
underestimation of the amount of the socket covered by the graft
because part of the deficiency (and hence the graft) is anterior—that
is, the deficiency is not just lateral; grafts in an anterolateral
location are only partially visualized on anteroposterior radiographs.
In other cases, the anteroposterior pelvic radiograph leads to an
overestimation of how much of the cup is covered by the graft because
socket contact with the host anterior or posterior column is not
visible. The amount of the acetabular component that can safely be
left uncovered is not known. Bone grafts were not used routinely
unless at least 1.5 cm of the anterolateral surface of the cup would
have been uncovered with the cup in a good position. The bone grafts
in this series served two purposes: (1) to provide additional anterolateral
support for the socket in the face of host bone deficiency, and
(2) to potentially provide future augmentation of bone stock. The
function of the grafts in this series represents a continuum: they
provided both support and bone stock augmentation in more severe
cases, whereas they provided mostly bone stock augmentation in milder
cases.
Variable results of the use of cemented sockets with autologous
femoral head bone grafts for the treatment of hip dysplasia have
been reported9,10,14,16,17,26,27.
In general, early results have been favorable, but they have deteriorated
with time, mostly because of an increasing revision rate as a result
of socket loosening or graft collapse. Gerber and Harris14 reported that 21% of forty-seven
cups were loose or had been revised at a mean of 7.1 years; Mulroy
and Harris17 reported that by
11.8 years the failure rate had increased to 46%. Similarly,
Lee et al.16 found that the rate
of mechanical failure in thirty-six hips with dysplasia that had
been treated with a cemented cup and a graft increased from 6% at
five years to 39% at ten years. However, Inao et al.27 found that none of twenty cups followed
for 5.2 to 12.9 years after reconstruction with a graft had been
revised, although three had radiographic signs of loosening. The
amount of resorption of autologous bulk bone with time also has
varied in series of cemented sockets10,17,26.
Most authors, even those reporting a high rate of failure with time,
have found that the autografts contribute valuable pelvic bone stock
that facilitates subsequent revision.
Uncemented sockets in combination with autogenous bone graft
provided good acetabular fixation in the young patient population
in our study at five to 12.9 years. Only two hips were revised because
of socket loosening or socket fracture, and, in retrospect, one
of these failures could have been predicted because most of the
socket rested on graft. There have been several other studies of
femoral head autografts used in combination with an uncemented socket12,18,19,28. Barrack and Newland6 noted no failures in ten hips within
three years. Morsi et al.v found
that only one of seventeen hips that had been reconstructed with
a bulk femoral head autograft and an uncemented cup had been revised
at a mean of 6.6 years. Four hips had minor graft resorption. Hintermann
and Morscher29 reported that,
of thirty-nine hips reconstructed with an autograft and an uncemented
cup, two had been revised because of cup loosening at a mean of
7.6 years. Graft resorption involving the loaded area over the cup
was seen in two hips. Anderson and Harris30 reported
that, of twenty dysplastic hips followed for at least five years
after reconstruction with use of an uncemented cup, none had mechanical
failure. Bulk bone graft had been used in four hips, and none showed
resorption.
The majority of the grafts used in the present series appear
to have augmented pelvic bone. This is an important advantage of
the technique since many patients with hip dysplasia are young and
require additional hip operations. The follow-up period was sufficient
to demonstrate that the grafts had united and had partially remodeled,
but without biopsy data it is uncertain whether they were vascularized
or incorporated. Most graft resorption was mild and involved bone
lateral to the socket that probably was not stressed and would be expected
to resorb according to Wolff’s law. However, it is also
possible that graft resorption occurs gradually from the outer graft
margin and with time progresses over the cup. Only one cup failed
as a result of graft collapse, a failure mode that is common with
cemented sockets used with femoral head autograft. Bone growth into
uncemented sockets in areas not supported by graft may provide protection
against socket loosening even if some graft resorption occurs.
This study showed that uncemented sockets with a bulk femoral
head autograft can provide good acetabular fixation and augmentation
of pelvic bone stock. The method preserves more host bone than either
a high hip center or a medial protrusio technique does. We believe
that the different available techniques of acetabular reconstruction
are each applicable to specific patients with hip dysplasia. For
mild deficiency, we prefer to medialize the socket to, but not through,
the medial wall of the pelvis and to place it without cement or
structural bone graft. In this situation, a bulk graft is not necessary
for socket stability and provides limited bone restoration. For moderate
anterolateral bone deficiency, we ream to the medial wall near or
a little above the normal hip center and use structural autogenous
bone graft to augment lateral acetabular coverage. For severe lateral
deficiency in which much of the cup would be supported by bone graft
even after medialization to the medial wall, we prefer to elevate
the hip center and place a small uncemented socket on host bone,
usually without a graft.
McQueary FG,Johnston RC. Coxarthrosis after congenital dysplasia. Treatment by
total hip arthroplasty without acetabular bone-grafting. J Bone Joint Surg Am,1988;70: 1140-4. 701140
1988
[PubMed]
Pagnano W, Hanssen AD, Lewallen DG,Shaughnessy WJ. The effect of superior placement of the acetabular component on
the rate of loosening after total hip arthroplasty. J Bone Joint Surg Am,1996;78: 1004-14. 781004
1996
[PubMed]
Russotti GM,Harris WH. Proximal placement of the acetabular component in total
hip arthroplasty. A long-term follow-up study. J Bone Joint Surg Am, 1991;73: 587-92. 73587
1991
[PubMed]
Dorr LD, Tawakkol S, Moorthy M, Long W,Wan Z. Medial protrusio technique for placement of a porous-coated hemispherical
acetabular component without cement in a total hip arthroplasty
in patients who have acetabular dysplasia. J Bone Joint Surg Am,1999;81: 83-92. 8183
1999
[PubMed]
Hartofilakidis G, Stamos K, Karachalios T, Ioannidis TT,Zacharakis N. Congenital hip disease in adults. Classification of acetabular deficiencies
and operative treatment with acetabuloplasty combined with total
hip arthroplasty. J Bone Joint Surg Am,1996;78: 683-92. 78683
1996
[PubMed]
Barrack RL,Newland CC. Uncemented total hip arthroplasty with superior acetabular deficiency.
Femoral head autograft technique and early clinical results. J Arthroplasty,1990;5: 159-67. 5159
1990
[PubMed]
Garvin KL, Bowen MK, Salvati EA,Ranawat CS. Long-term results of total hip arthroplasty in congenital
dislocation and dysplasia of the hip. A follow-up note. J Bone Joint Surg Am,1991;73: 1348-54. 731348
1991
[PubMed]
Raut VV, Stone MH, Siney PD,Wroblewski BM. Bulk autograft for a deficient acetabulum in Charnley
low-friction arthroplasty. A 2-9-year follow-up study. J Arthroplasty,1994;9: 393-8.. 9393
1994
[PubMed]
Ritter MA,Trancik TM. Lateral acetabular bone graft in total hip arthroplasty.
A three- to eight-year follow-up study without internal fixation. Clin Orthop,1985;193: 156-9. 193156
1985
[PubMed]
Rodriguez JA, Huk OL, Pellicci PM,Wilson PD Jr. Autogenous bone grafts from the femoral head for the treatment
of acetabular deficiency in primary total hip arthroplasty with
cement. Long-term results. J Bone Joint Surg Am, 1995;77: 1227-33. 771227
1995
[PubMed]
Shinar AA,Harris WH. Bulk structural autogenous grafts and allografts for reconstruction
of the acetabulum in total hip arthroplasty. Sixteen-year-average
follow-up. J Bone Joint Surg Am,1997;79: 159-68. 79159
1997
[PubMed]
DeLee JG,Charnley J. Radiological demarcation of cemented sockets in total
hip replacement. Clin Orthop,1976;121: 20-32. 12120
1976
[PubMed]
Kaplan EL,Meier P. Nonparametric estimation from incomplete observations. J Am Statist Assn,1958;53: 457-81. 53457
1958
Gross AE,Catre MG. The use of femoral head autograft shelf reconstruction
and cemented acetabular components in the dysplastic hip. Clin Orthop, 1994;298: 60-6. 29860
1994
[PubMed]
Inao S, Gotoh E,Ando M. Total hip replacement using femoral neck bone to graft
the dysplastic acetabulum. Follow-up study of 18 patients with old
congenital dislocation of the hip. J Bone Joint Surg Br,1994;76: 735-9. 76735
1994
[PubMed]
Morsi E, Garbuz D,Gross AE. Total hip arthroplasty with shelf grafts using uncemented cups.
A long-term follow-up study. J Arthroplasty,1996;11: 81-5. 1181
1996
[PubMed]
Hintermann B,Morscher EW. Total hip replacement with solid autologous femoral head graft
for hip dysplasia. Arch Orthop Trauma Surg, 1995;114: 137-44. 114137
1995
[PubMed]
Anderson MJ,Harris WH. Total hip arthroplasty with insertion of the acetabular
component without cement in hips with total congenital dislocation or
marked congenital dysplasia. J Bone Joint Surg Am, 1999;81: 347-54. 81347
1999
[PubMed]
Silber DA,Engh CA. Cementless total hip arthroplasty with femoral head bone grafting
for hip dysplasia. J Arthroplasty,1990;5: 231-40. 5231
1990
[PubMed]
Wolfgang GL. Femoral head autografting with total hip arthroplasty
for lateral acetabular dysplasia. A 12-year experience. Clin Orthop,1990;255: 173-85. 255173
1990
[PubMed]
Gerber SD,Harris WH. Femoral head autografting to augment acetabular deficiency in
patients requiring total hip replacement. A minimum five-year and
an average seven-year follow-up study. J Bone Joint Surg Am,1986;68: 1241-8. 681241
1986
[PubMed]
Harris WH, Crothers O,Oh I. Total hip replacement and femoral-head bone-grafting for severe
acetabular deficiency in adults. J Bone Joint Surg Am,1977;59: 752-9. 59752
1977
[PubMed]
Lee BP, Cabanela ME, Wallrichs SL,Ilstrup DM. Bone-graft augmentation for acetabular deficiencies in
total hip arthroplasty. Results of long-term follow-up evaluation. J Arthroplasty,1997;12: 503-10. 12503
1997
[PubMed]
Mulroy RD Jr,Harris WH. Failure of acetabular autogenous grafts in total hip arthroplasty.
Increasing incidence: a follow-up note. J Bone Joint Surg Am,1990;72: 1536-40. 721536
1990
[PubMed]
Convery FR, Minteer-Convery M, Devine SD,Meyers MH. Acetabular augmentation in primary and revision total
hip arthroplasty with cementless prostheses. Clin Orthop,1990;252: 167-75. 252167
1990
[PubMed]
Zlatic M, Radojevic B,Lazovic C. Reconstruction of the hypoplastic acetabulum in cementless arthroplasty
of the hip. Int Orthop,1990;14: 371-5.. 14371
1990
[PubMed]
Crowe JF, Mani VJ,Ranawat CS. Total hip replacement in congenital dislocation and dysplasia of
the hip. J Bone Joint Surg Am,1979;61: 15-23. 6115
1979
[PubMed]
Wiberg G. Studies on dysplastic acetabula and congenital subluxation
of the hip joint. With special reference to the complication of osteo-arthritis. Acta Chir Scand,1939;83: 58). 8358
1939
Sharp IK. Acetabular dysplasia. The acetabular angle. J Bone Joint Surg Br, 1961;43: 268-72. 43268
1961
Tönnis D. Congenital
dysplasia and dislocation of the hip in children and adults. New
York: Springer; 1987.