الفهرس 
Chapter (1): AnatomyOnly 14 pages are availabe for public view
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Abstract
The number of hip arthroplasties done every year is rising up,
leading to more cases that need revision. One of the main issues in the
revision surgery as well as complex primary total hip arthroplasty is
acetabular reconstruction. It is mandatory to reconstruct acetabular
defects to help the surgeon to reach the main target of this type of
surgery; a stable well-positioned construct.
Several classification systems were hypothesized in order to
accurately classify these defects and try to make a clear specification for
each type of reconstruction techniques reported in the literature. The most
common and well-known classification systems are those popularized by
Paprosky et al and AAOS systems.
For long periods surgeons tried to reconstruct acetabular defects
using biological methods in the form of bone grafts either bulk or
morselized impaction grafts. The long term complications of bulk grafts make the surgeons look for other techniques to avoid re-revisions caused
by bone graft resorption.
The literature is full of reports of different types of cages and rings
used to overcome the obstacles in revision surgeries. Lack of modularity
of these systems and the technical challenge in their application as well as
the reported complications of them limited their use to specific types of
acetabular defects.
Continuous research went on for long time to find a material that
suits the requirements needed for long term use. Tantalum has already
proved its superior qualities compared to other materials regarding longterm
durability, osteointegration and its close-resemblance to bone
characteristics. Studies reporting the results of using tantalum in the form of
cementless shells preceded the use of porous augments for the
reconstruction of defects. The early successful results of porous metal
shells encouraged the surgeons to start using tantalum augments.
Early to midterm follow up results of using tantalum augments were
published showing high success rate and promising clinical and
radiological results. This was one of the main reasons to start this thesis
in Menoufia University Hospitals trying to find an effective solution for
the complex primary and difficult revision cases referred to our hospital.
This study started in 2012 to report the clinical and radiological
outcome of using trabecular metal augments made of tantalum in hip
arthroplasty for 20 hips that had an acetabular defect less than Paprosky
grade 3B or pelvic discontinuity. Twenty patients were followed up for a mean of 34.5 months after
the surgery. Both clinical and radiological evaluation for these cases were
done. Clinical evaluation including HHS, OHS and ambulatory score
preoperatively and at the latest follow up were done. Radiological
assessment for the augments and whole construct utilized Moore et al.
criteria for osteointegration of trabecular metal shells that was modified
for the augments by Abolghasemian et al.
Preoperative planning in acetabular reconstruction represents the
corner stone in the success of this type of surgery. In revision cases,
patients should be notified with the expected time to return to their
activities and the possibility of complications.
In this study, we used tantalum augments for six patients in addition
to a primary prosthesis. This category of patients were divided in two halves, three of them had cemented cups and the other three had cementless components. The remaining fourteen hips were revisions. One
case only had a cementless dual mobility cup and the remaining thirteen
had cemented cups.
This study includes eight cases that were diagnosed with infection
preoperatively. According to the protocol of management of infected
cases, one patient had two stage revision surgery and the other seven
underwent a single stage procedure. Impaction bone grafting was used in
eight cases to reconstruct associated cavitary defects.
Ten cases of the revision group needed trochanteric osteotomy for
the femoral side. Standard osteotomy was done in two cases and extended
osteotomy was done in eight cases. Reattachment was done in all cases
using soft wires.
All cases had improved clinical scores postoperatively with only one
fair result according to HHS grading. All the patients were satisfied with
the overall procedure and postoperative pain relief. Full weight bearing
started at 1.5 months in cases without trochanteric osteotomy. It was
postponed to 3 months for cases that had trochanteric osteotomy.
Intraoperative periprosthetic femoral shaft fracture occurred in one
case that was managed with a plate. Late dislocation occurred in one case
and was managed with closed reduction. No cases of reinfection were
reported and no revisions were done.
Radiological assessment of these augments found them to be stable
at early to mid-term follow up. No signs of cup migration were found.
Only one sign of instability appeared in one case in the form of a nonprogressive
radiolucent line that didn‘t need revision.
The promising early results of using this technique for acetabular
reconstruction convinced more surgeons to start using this system in revision surgeries. Given its modularity and the ability to reconstruct
different types of defects with no fear of bone resorption, porous metal
augments are considered a valuable method in the management of
acetabular defect. Augments are stable at midterm follow-up, can be used
in different types of defects, technically easy and there is no fear of
resorption.