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MARTES / TUESDAY
42
HIP RESURFACING FOR
OSTEONECROSIS
Harlan C. Amstutz, MJ Le Duff
Joint Replacement Institute,
Los Angeles (USA)
INTRODUCTION
The results of THA and prior hip resurfacing designs with
Polyethylene in osteonecrosis (ON) have been less satisfactory
than for patients with other etiologies. Metal-on-metal
(MM) resurfacing is bone preserving and stable and permits
a wide selection of revision options for young patients.
METHODS
From a cohort of 1000 hips of all etiologies, 84 hips (70 patients,
avg. age 40.1 years), with ON Ficat Stage III (19 hips)
and IV (65 hips) were treated with hybrid MM resurfacing.
81% were males and 19% female. 33.3% had previous surgeries
including core decompressions (17 hips), hemi-resurfacing
arthroplasty (3 hips), pinning (5 hips), free vascularized
fibula graft (2 hips) and Judet graft (1 hip). 71 hips (85%)
presented femoral head defects larger than 1cm and none
were excluded because of the size of the defect.
RESULTS
The average F/U was 6.2 years (1.5-11). Average femoral
component size was 46.3mm. The clinical scores were comparable
to that of the rest of the cohort except for the activity
score which was lower in average (7.0 vs.7.5, p=0.0015).
Three hips were revised: 2 for femoral loosening at 22 and
61 months, and one for a fracture of the acetabular wall (over
reaming in osteopenic bone) with protrusio of the cup one
day post surgery. There were no other complications. X-ray
analysis revealed 3 cases of neck narrowing (1 bilateral) and
2 cases of femoral radiolucencies in 3 zones around the
metaphyseal stem. The Kaplan-Meier 5-year survival estimate
was 97.1% (95% Confidence Interval 88.7 to 99.2). There
has been no femoral component loosening for patients implanted
after August of 1997.
CONCLUSION
Our results highlight that the etiology of osteonecrosis itself
does not constitute a contraindication for resurfacing despite
large defects. Technique is critical in achieving initial femoral
fixation and promoting long-term durability. Those patients
who had large defects are advised to refrain from impact
activities.
AVASCULAR NECROSIS AND HIP
RESURFACING
Michael Menge, Clemens Nitschke
St. Marienkrankenhaus,
Ludwigshafen (Germany)
BACKGROUND
Osteonecrosis (AVN) of the femoral head very often affects
patients between the age of 20 and 50 years of age. In many
cases conservative treatment will not be sufficient and
arthroplasty has to be performed. As in these mostly younger
patients life expectancy will be normal it may be helpful using
a resurfacing device first to keep standard total hip replacement
as a second chance procedure.
Method: Between 1999 and 2006 more than 1.500 patients
received a MoM resurfacing of the hip. From those patients
35 patients received a resurfacing for a stage four posttraumatic
or localized AVN. We excluded patients with metabolic
disorders or continued steroid medication. There were
two additional cases of sickle cell anaemia. The technique
in these cases will be described and the problems will be
discussed.
RESULTS
The intraoperative findings and the technique will be demonstrated.
Mostly the neck of the femur will have to be shortened
significantly. Lateralizing the acetabular socket can partially
retain the offset. Only two patients had to be revised due to
neck fracture according to progressive necrosis.
CONCLUSIONS
In our limited series of AVN treated with resurfacing of the
hip the outcome was better than in standard hip THR. In
about 6% the osteonecrosis progressively lead to a neck
fracture and to conversion to a standard stem with big head
metal to metal articulation.
RESURFACING IN THE
ELDERLY PATIENT
Michael Menge
St. Marienkrankenhaus,
Ludwigshafen (Germany)