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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. |