|
In this patient group
there have been 17 failures.
6
Infections
4 Fractured neck of femur
3 Cup breakouts
1 Femoral loosening
1 AVN
1 Collapsed femoral head from extensive AVN
1 Fractured acetabulum.
|
|
In the five
patients with infection, one had previous surgery and previous
hip infection and one patient was diabetic.
In
the four patients with fractured neck of femur two were over
the age of 70yrs and had marked osteoporosis.
|
| Now
both these patients would be regarded as contra-indications both
on account of age and osteoporosis. |
|
In the two
younger patients one had generalised DEXA scan proven, osteoporosis
and one had renal osteodystrophy from renal failure, avascular
necrosis and was on steroids for SLE.
|
|
All
the fractured neck of femurs occurred within the first three
post-operative months.
There have been no long term fractured necks of femur including
our pilot series extending back eight years nine months.
|
|
The
three cup breakouts were all early complications
|
|
Two patients
had previous Chiari osteotomies and one patient had acetabular
dysplasia.
|
| All
of these cups were inserted prior to the development of the dysplasia
cup which allows supplementary screw fixation and bone grafting
of the acetabular deficiency. |
|
In
the one patient who sustained a fractured acetabulum at the
primary surgery the bone was of very poor quality because of
renal failure, a renal transplant and renal osteodystrophy.
|
| There was
one revision in the series for avascular necrosis of the femoral
head. |
|
Fifteen
out of the seventeen failures presented within the first
post-operative year.
|
|
In
the first 100 Hybrid hip resurfacings the demographics are as
shown:
|
|
|
|
100
Hip Resurfacings in 95 Patients
|
|
41
Female
|
54
Male
|
|
45
Left
|
55
Right
|
|
| |
|
The
presenting pathology in these 100 hips is as shown:
|
 |
|
The
average age in this group was:
48.3
years (18 – 74 yrs)
Mean follow up – 59 months (52 – 68 mths)
|
|
Out
of the first 100 Hybrid resurfacings there have been two failures:
|
| one infection
& one femoral head collapse in a patient with extensive previous
idiopathic AVN. |
|
There
were two deaths from unrelated causes,
|
one at 4
yrs 9 months post-operative from septicaemia following chemotherapy
for breast carcinoma &
one at 4 yrs 6 months from a cerebro-vascular accident. |
|
There
were no cases of acetabular loosening as judged by progressive
radiolucent lines, change in position of component or obvious
migration.
|
|
There
were no cases of femoral loosening as judged by change in position
or obvious migration.
|
| There were
however enormous problems with the peripherally expanded HA on
smooth Hybrid cup in use at that time. The peripheral expansion
meant that in many cases the acetabular component did not reach
the prepared acetabular floor. |
|
In
these first 100 hips 48 components were not fully seated.
|
| |
 |
| As
can be seen that incomplete seating varied from 0.5mm to 10mm. |
|
On
post-operative X-ray only 13 cases with no radiolucency were
seen but happily by three plus years most of the gaps had filled
in and 74 hips had no radiolucency at the cup bone interface.
|
Radiolucent
Lines
| Post-op |
|
3+
years |
|
| One
Zone |
-
13 |
One
Zone |
-
15 |
| Two
Zones |
-
47 |
Two
Zones |
-
7 |
| Three
Zones |
-
25 |
Three
Zones |
-
2 |
| No
Radiolucency |
-
13 |
No
Radiolucency |
-
74 |
|
|
As
can be seen that poor acetabular component seating gave poor
post-operative appearances on x-ray.
|
|
This
poor intra-operative seating of the acetabular component has
been solved with the Birmingham Hip Resurfacing which is a spherical
component and like many other uncemented total hip replacement
cups employs 2mm of under reaming. It is then straight forward
to get full seating of the acetabular component in the prepared
bony bed
|
|
80
hips were classified as Charnley category A or B and these patients
had no built-in restraint from other conditions to their activity
level.
|
|
Merle-D' Aubigne'
Scores in Charnley A+B
Catergories
80
Hips
| Pain |
- |
5.99
|
| Walking |
- |
5.95
|
| Movement |
- |
5.96
|
|
| In these
80 hips the pain, walking and movement scores are extremely good. |
|
Heterotopic
ossification was not a problem and no patient has hip stiffness
as a result of heterotopic ossification.
|
Hetertopic Ossificaction
(Brooker)
| No
Ossification |
- |
76
|
| Grade1 |
- |
18
|
| Grade2 |
- |
1
|
| Grade3 |
- |
3
|
| Grade4 |
- |
0
|
|
| At this time
all patients were given prophylactic Indomethacin in the five
post-operative days. |
