Long-term stability of total hip arthroplasty (THA) depends on the integration between osseous tissue and the biomaterial implant. Integrity of the osseous tissue requires the contribution of mesenchymal stem cells and their continuous differentiation into an osteoblastic phenotype.

Some studies, like Wang ML et al., show that chronic exposure to titanium and zirconium oxide wear debris may contribute to decreased bone formation at the bone/implant interface by reducing the population of viable human mesenchymal stem cells (hMSCs) and compromising their differentiation into functional osteoblasts.

On the basis of our good experience in the use of Exeter technique in revision surgery of THA, two years ago we started to utilize bone grafts mixed with growth factors in order to improve grafts incorporation and implant fixation. At the moment we are studying the use of hMSCs during hip revision surgery, employing polyethylene cup to reduce the possible titanium and zirconium oxide debris. hMSCs are obtained with MarrowsStim Concentration Kit (Biomet Biologics Europe) by 60 ml of patient’s bone marrow.

Clinical outcomes and quality of life are evaluated on the basis of Harris Hip Score, Womac score and SF-36 score, while bone graft incorporation features are assessed with post operative computed tomography (CT) examination and further CT controls at two, four and eight months after surgery.

In the last months of 2007 we started to retrospectively review 60 patients who had undergone Girdlestone resection arthroplasty of the hip between 1994 to 2006.

The most frequent indications for this procedure were sepsis around prosthesis, aseptic loosening, pseudoartrhosis after femoral neck fractures or medical compromised patients who had an high risk of hip reimplantation procedure. The evaluation of patient’s satisfaction ranges a lot in literature and no valid guidelines have been publicated.

All our patients were submitted to limb shortening measurement and functional evaluation according to SF-36 score and Harris Hip Score. There were 20 men and 40 women with an average age of 70 years old (range 96-43 years old on operation time), the mean follow up was 133 months (range 14–167 months). Some patients were lost at the follow-up, the main reason was death for related and unrelated causes (overall mortality of 30%).

The aim of this study was to analyze patient’s satisfaction and functional outcomes after Girdlestone arthroplasty which appears in our experience, despite the limits, a valid surgical option in order to improve hip function, decrease or cancel pain and control infections when implantation or reimplantation is not possible.

Femoral off-set is the perpendicular distance between femur longitudinal axle and the femoral head’s rotation’s centre. Femoral off-set influences following yardsticks: stability of the joint, range of movement (ROM), muscular forcibleness, solicitations on the femoral component and acetabular component’s usury. From numerous radiographies studies, is shown as off-set is not an indefeasible measure, but an average with a range of variability. Offset is one of the most important yardsticks to consider during the pre-operating planning since, as is broadly documented, it has a positive effect on the functionality of the prosthesis; difficulty remains to individualize the optimal offset value in patient with bilateral coxofemural pathology or carriers of opposite side total hip prosthesis. Modular necks act indipendently in three spatial variables allowing to reach 27 points in the space, disposing of heads with three lenghts the real disponibility become of 81 points.

Usually we estimate the sizes and the orientation of the components manually and through a radiographic intra-operative control in order to choose the best match head-neck.

If we make a minimum mistake in cup position, the use of modular necks allow to correct this failure to obtain the most correct anatomic position producing negligible debris and the reduction of the mechanic stress.

Basing on our experience we think that the possibility to change length and version independently and sequentially is the unique technique avaible to correct the implant’s orientation, even if in our series we have choose neutral neck in most cases. To obtain better functional outcome we are studing a device based on gait analysis and superficial electromyography to calculate pre and post operative off-set. The data that we have achieved are still too few to be able to produce results; if there is possible, presenting them in future editions.