Between September 1987 and December 1993, a total of 2237 primary
cementless total hip arthroplasties were performed for the treatment
of osteoarthritis at our institution by the two senior authors (R.H.R.
and W.J.H.). One hundred and twenty-three (5%) of these
procedures were performed in 114 patients between the ages of eighty and
eighty-nine years. To provide a more complete picture of the perioperative
complications, this entire original group was analyzed. Of the 114 patients,
seven (eight hips) died within two years (range, five to twenty-two
months) after the surgery. None of these patients died of causes
related to the hip surgery. Additionally, seventeen patients (eighteen
hips) died more than two years postoperatively but had not returned
for follow-up. Five hips were lost to follow-up. Thus, eighty-six
patients (ninety-two hips) were available for review at two to eleven
years (mean, five years) after the operation (Table I). (One patient
with bilateral total hip replacement was followed for more than
two years on only one side.) There was no significant difference
regarding age (p = 0.95; t test), side (p = 0.28;
chi-square test), or preoperative Charnley pain or function score
(p = 0.78 and p = 0.72, respectively; chi-square
test) between the twenty-nine patients (thirty-one hips) followed
for less than two years (died or lost to follow-up) and the eighty-six patients
(ninety-two hips) followed for two years or more. The only difference
was that there were more men in the group followed for less than
two years (p = 0.01; chi-square test).
The cementless acetabular component was the Universal cup I (Biomet,
Warsaw, Indiana), which is a hemispherical titanium-alloy
component with a plasma-spray coating. The peripheral flange has
a flare to provide a press-fit. The plasma-spray coating increases
the outer diameter by 1 mm compared with the reamed diameter, thereby
further enhancing stability. The cup liner is a cylindrical shell
with both standard and high-wall options. The technique for insertion
of the acetabular cup included routine use of titanium screws inserted
through the dome for supplemental fixation.
The cementless femoral component was the Taperloc femoral stem
(Biomet). This component is composed of titanium alloy with a circumferential plasma-spray
coating on its proximal third. It is a collarless, tapered, wedge-shaped
implant and is available with a lateral-offset option. Insertion
of the femoral component requires no endosteal reaming. Broaching
achieves a solid cortical press-fit. The broach is used as a trial
to check for stability and leg length. The permanent implant is
then inserted with firm impaction. Stability of the prosthesis is
manually tested by twisting the screwed-in handle used for insertion
of the prosthesis. Excellent intraoperative stability was perceived
in every patient, despite variation in bone stock.
All patients were instructed to bear approximately 10% of
their weight on the treated extremity for six weeks, at which time
they were advanced to a cane. A low-dose warfarin protocol was used,
with 10 mg given on the night of the surgery and the dose subsequently
adjusted daily to maintain the prothrombin time at fifteen seconds.
Objective preoperative and follow-up evaluation was performed
by specially trained physical therapists or research fellows. Clinical
evaluations were performed preoperatively, at six weeks postoperatively,
and then yearly with use of the Charnley modification of the Merle
d’Aubigné and Postel scale17.
The Harris hip-scoring system18 was
incorporated into the clinical evaluation at our institution later
in the study period, so a preoperative Harris hip score was not
available for seventeen of the ninety-two hips. The patient was
questioned specifically about thigh or groin pain, which was recorded
as present or absent.
Leg-holders were used to position the limb accurately for sequential
radiographic review, and the distance between the film and the x-ray
tube was constant. The quality of the bone stock preoperatively
was categorized radiographically with the method described by Dorr
et al.19. Subsidence of the femoral
component was defined as a change in position of more than 3 mm.
All changes around the cementless femoral component were documented
with a modification of the system suggested by Engh et al.20-22. The femoral component was classified
as stable with bone ingrowth, stable with fibrous ingrowth, or unstable.
Mechanical failure was deemed to have occurred if the femoral component
was revised for loosening or was considered to be radiographically unstable.
The position of the acetabular component was determined according
to the criteria of Massin et al.23.
Any change in component position of either 3 mm or 3° was considered
to represent migration of the cup, a definite sign of cup-loosening24. Radiolucency of greater than 1
mm in thickness at the component-bone interface was looked for in
the three zones defined by DeLee and Charnley25.
Cup wear was assessed according to the technique of Livermore et
al.26. Briefly, the shortest distance
between the center of the femoral head and the edge of the metal
cup was used for this evaluation. Each radiograph was measured by
a single observer to the nearest 0.25 mm with use of the X-caliper
(Eisenlohr Technologies, Davis, California). This is an electronic
caliper that automatically corrects for magnification on the basis
of a known variable such as the actual femoral head size.
Statistical Analysis
Categorical variables were analyzed with use of a chi-square
test27. Statistical comparison
to test for differences between two groups was performed with the
Student t test for uncorrelated means27.
All analysis was done with StatView 5.0 (SAS Institute, Cary, North
Carolina).
Clinical Results
There was substantial improvement in pain relief, function, and
motion following the total hip arthroplasties. At the last follow-up
evaluation, the mean Harris hip score was 82 ± 13
points (range, 49 to 100 points). The Harris hip score was not determined
for six patients (six hips) at the last office visit: two of them
had died, and we were unable to contact the remaining four by telephone
or letter. According to information recorded in the office charts,
four of these six patients reported no pain, one had slight pain
with tenderness over the greater trochanter, and one had moderate
pain over an ununited greater trochanter. Neither of the latter
two patients had radiographic signs of loosening of the prosthesis.
As previously mentioned, because the Harris hip score was not incorporated
into the clinical evaluation in the beginning of this study, preoperative
scores were available for only seventy-five of the ninety-two hips;
the mean score for these seventy-five hips was 40 13 points (range,
15 to 78 points). The sixty-nine hips with both preoperative and
postoperative Harris hip scores had a mean increase of 42 points.
The mean Charnley score for pain improved from 2.7 points (2,
3, or 4 points) preoperatively to 5.7 points (range, 3 to 6 points)
at the time of the latest follow-up, the mean score for function
improved from 2.8 points (range, 1 to 5 points) to 4.2 points (range,
1 to 6 points), and the mean score for motion improved from 4.0
points (range, 2 to 6 points) to 5.2 points (4, 5, or 6 points).
Of the ninety-two hips, 77% (seventy-one) were not considered
to be painful by the patients and 17% (sixteen) were considered
to be mildly painful without limitation of activity. Four (4%)
of the hips were associated with pain in the thigh. Each of these patients
had radiographic evidence of osseous ingrowth, and each had a Charnley
pain score of 5 points. Five (5%) of the ninety-two hips
had pain that was considered limiting, and the location of the limiting
pain was described as the groin (one hip), buttock (one hip), or
trochanter (three hips).
At the time of the most recent follow-up, the eighty patients
(eighty-six hips) with an available postoperative Harris hip score
were evaluated with regard to whether they could walk six blocks
or more without an assistive device (24% [twenty-one] of the
eighty-six hips); could walk six blocks or more with support (10% [nine] of
the hips); could walk outdoors for a distance of less than six blocks
(31% [twenty-seven]), either with support
(nineteen) or without support (eight); could walk only indoors (31% [twenty-seven]);
or could not walk because of medical conditions unrelated to the
hip surgery (2% [two, neither of which was painful]).
They were also evaluated with regard to whether they required a
walker for walking (20% [seventeen]),
had difficulty putting on shoes and socks (43% [thirty-seven]),
and could ascend and descend stairs (86% [seventy-four]).
There were no femoral or acetabular revisions.
Radiographic Results
Of the ninety-two hips that were evaluated after at least two
years, 85% (seventy-eight) were followed radiographically
for two years or more (mean, five years; range, two to ten years).
Eleven hips were followed for less than two years, and we were unable
to find the follow-up radiographs for three hips.
The acetabular cup angle averaged 42° (range, 27° to 60°). No
socket demonstrated migration (definite loosening), and none showed
complete bone-prosthesis lucency consistent with probable loosening.
Wear was measured on the immediate postoperative radiograph and
on radiographs made at the time of the most recent follow-up. These
radiographs were available for seventy-three of the seventy-eight hips.
Of these, 41% (thirty) had a 22-mm femoral head and 59% (forty-three)
had a 28-mm head. Forty-three percent (thirteen) of the thirty 22-mm sockets
and 40% (seventeen) of the forty-three 28-mm sockets demonstrated
measurable wear. Linear cup wear averaged 0.076 mm/yr for
the hips with a 22-mm femoral head and 0.074 mm/yr for
those with a 28-mm head. Volumetric wear was 29 and 46 mm3/yr, respectively. Acetabular
lysis was seen in 4% (three) of the seventy-eight hips;
two had a 22-mm head and one, a 28-mm head.
According to the system of Dorr et al.19,
17% (fifteen) of the ninety hips in which bone type was
evaluated had type-A cortical bone; 58% (fifty-two), type-B;
and 26% (twenty-three), type-C. Two hips did not have available
radiographs for this evaluation. The clinical results were independent
of bone type. According to the classification system of Engh et
al.20, all of the femoral components
had radiographic evidence of bone ingrowth. No component was unstable,
and no fibrous ingrowth was seen. None of these cementless femoral
components had evidence of mechanical failure (that is, either a
revision or radiographic evidence of failure) at a mean of five
years (range, two to eleven years) after the arthroplasty. Despite
the high prevalence of polyethylene wear and the presence of acetabular osteolysis,
there was only one case of femoral osteolysis. This osteolysis was
localized at the proximal-medial aspect of the femoral neck, proximal
to the coating of the prosthesis.
Complications
In the original group of 123 hips, the rate of medical complications
was 24% (thirty hips). The complications included femoral
nerve palsy (associated with one hip [0.8%]),
with total recovery by six months; urinary tract infection (five
hips [4.1%]); pulmonary emboli (eight
hips [6.5%]), none of which were symptomatic
and all of which were detected on routine postoperative lung scans;
cardiac abnormalities (three hips [2.4%]),
consisting of one case of congestive heart failure, one case of angina,
and one case of atrial fibrillation; gout attack (three hips [2.4%]);
intestinal ileus (three hips [2.4%]);
peptic ulcer (one hip [0.8%]); seizure (one
hip [0.8%]); urinary retention (six hips [4.9%]);
and enterocolitis (two hips [1.6%]).
It is important to note that there were no perioperative deaths.
Equally important are the results involving perioperative
component-related complications. There were no femoral fractures,
dislocations, or infections. One patient did eventually have recurrent
dislocations (a total of nine dislocations treated by closed reduction)
but declined operative intervention. Two patients sustained a periprosthetic fracture
at 1.5 and six years postoperatively. Both fractures were related
to a fall. One was treated with traction, and the other was treated
with open reduction and internal fixation.
We are not aware of any other reports in the literature on the
efficacy of primary cementless total hip arthroplasty in octogenarians.
There are a few related reports on the use of cementless total hip arthroplasty
in older patients. Engh et al.22 reported
good results with the use of the AML prosthesis (DePuy, Warsaw,
Indiana) in patients older than sixty-five years. Survivorship probabilities
with revision and mechanical failure as the end points were 98.6% and
92.5%, respectively, at eight years. There were three stem
revisions, one because of stem breakage and two because of failure
of biologic stabilization. The rate of revision because of failed
biologic stabilization was only 0.6% at a mean of six years.
McAuley et al.28 reported a cumulative
probability of prosthetic survival of 0.92 at twelve years, with
any reoperation as the end point, in patients sixty-five years of
age or older who were treated with different designs of the AML
femoral component and a fully porous-coated acetabular component.
The survival rate for the femoral component was 0.97, and that for
the acetabular component was 0.92. At a mean of 8.5 years, 91% (139)
of the 152 patients reported no or mild pain and had a normal activity
level.
Concerns regarding cementless total hip arthroplasty in the elderly
include persistent pain, failure of bone ingrowth, and cost6,8,9,29,30. Our data indicate no clinically
adverse consequences of cementless fixation in terms of pain and function.
Even patients with thigh pain had satisfactory clinical scores,
and all patients had radiographic evidence of bone ingrowth. The
decreased time required for insertion of an uncemented prosthesis
in this physiologically frail age-group is an advantage over arthroplasty
with cement. The time saved by avoiding curing of femoral and acetabular cement
mantles decreases blood loss and operative time. Fat embolism is
a well documented consequence of cement injection and pressurization11-13. Patterson et al.31 reported seven cases of cardiac
arrest during total hip replacement with cement and a long-stem
femoral component. Three patients were successfully resuscitated,
but four patients died. Factors that were common to all of these
patients were advanced age, a previously undisturbed intramedullary
canal, and osteoporotic bone. Cementless fixation is likely
to reduce the chance of this serious complication.
Many authors9,32 have based
implant selection on an arbitrary age and bone quality because of
the belief that initial implant stability may not be achievable
in the elderly. In our series, no prosthesis was thought to be unstable
when tested manually during surgery. Failure due to a lack of osseointegration
is also of concern in these patients. There were no instances of loosening
after a minimum two-year follow-up period in our patients. Therefore,
we concluded that the bone of elderly patients can provide adequate initial
stability for cementless implants, leading to subsequent bone ingrowth.
Cemented total hip components generally are considered to be
a less expensive and therefore a more appropriate option for the
elderly. The cost of the prosthesis alone is the usual basis of
comparison, even though many additional costs are incurred in the
implantation of a cemented stem and cup. For example, longer operative
time as well as the cement, cement-mixing setup, cement pressurizers, cement
restrictors, pulse irrigation, and cement guns are all associated
with costs. Barrack et al.33 examined
the costs of total hip replacement with a cemented or uncemented
stem and found the actual cost for a modern cemented stem to be
greater than that for an uncemented stem.
Persons eighty years of age or older are, by percentage, the
fastest growing segment of the American population, with their number
estimated to increase to nine million by the year 2000 and to thirty-two million
by the year 205034. Because of
their longevity, even this elderly group may require between ten
and twenty years of service from their implants35.
In conclusion, in the short term, cementless fixation for total
hip replacement in octogenarians can decrease pain and improve function.
Long-term biologic fixation may prove to be of benefit as these individuals
lead longer and more active lives.