Great diffusion of hip prosthetic surgery, in relatively-young patients too, generates as consequence an increase in prosthesis failures associated with limited or massive bone losses, making revision surgery mandatory, even in most advanced degrees of osteolysis.

In best surgery strategy planning are essential: - evaluation of osteolysis degree with standard x-Rays; - evaluation of periprosthetic bone turn-over with scintigraphy (both a specific as they give merely qualitative evaluations of bone remodeling); – quantitative evaluation of periprosthetic bone mineral density with periprosthetic mineralometry (D.E.X.A.). Data obtained with these methods allow more accurate decisions, during the pre-operative phase, regarding the most indicated implant for revision surgery: mid or long-stem, with or without omoplastic transplants, with or without materials promoting bone rehabitation. In any case, the surgeon must have all possible solutions in order to eventually change the operative plan during surgical act.

Following qualitative and quantitative periprosthetic bone evaluations, we use to classify stem and cup mobilizations with Italian Group for Revision (GIR) classification. According to GIR classification, our actual trends in the choice of revision prostheses, in the most advanced degrees of complex mobilizations of stem and cup, are the following: - GIR 3 (Enlargement of the femoral shaft with thinning of cortical bone and loosing of 2 or more walls; loosening and acetabular deformation with losing of one ore more columns and the bottom). In this degree we prefer a long-stem concept straight prosthesis; this prosthesis allows an immediately more stable implant, due to optimized length, in opposition to rotation forces and assuring force transfer in both proximal and distal direction. When osteolysis is wider, it was necessary a strategy change, searching a more distal locking of the implant, according to Wagner’s criteria. The SL Wagner’s prosthesis restores cohesion with the reabsorbed bone surface, generating a relative stability in the immediate post-op period; in the following 2 months, an intense bone apposition, which brings to a progressive filling of bone losses, takes place. For this purpose, it is not indicated, apart from surgical way used, cutting the muscle insertions around the thinned wall. This revision prosthesis is fixed without the use of cement due to the distal blocking, guaranteed by his conical shape; the stem is straight and it is not fit to the natural front-bending of femoral shaft. For this last explained reason, we follow these guidelines, improving our results, using a cementless anatomic modular stem: with this kind of implant design, that preserves cortical bone of femoral shaft from stress shielding, and the extremely wide (XX combination) choice of head and neck components, we are now able to regain as well as possible, the correct offset and center of rotation. For the acetabular loosening, we use to implant oval cups, that naturally fit the acetabular lesion, with or without bone grafts impaction in bone loss areas.- GIR 4 (Massive proximal bone loss all around the shaft; massive peri-acetabular loss). In the past we implanted wide-resection cemented (Muller) or non cemented (Kotz) prosthesis, originally designed for onchologic patients, to treat complete femoral osteolysis. The wide resection uncemented prosthesis, after follow up, supports the Wagner’s theory of distal support, because in spite of an almost complete bone sacrifice, there is an attempt of periprosthetic corticalization by the femoral bone. Since some years we implant even in this cases a modular distally-anatomic revision prosthesis, this type of prosthesis, thanks to his proximal component, provides a relative primary metaphyseal support, that improves global stability of implant. In massive peri-acetabular loss we prefer the use of oval components with peripheral supports and obturatory hook, with bone graft impaction. Only as “extrema ratio” we choose for the implant a McMinn stemmed cup.

From these guidelines, integrated with clinical observation at mid range follow-up, appears clerarly that cementless prosthesis in hip revision surgery, even in most advanced degrees of osteolysis, are really able to guarantee good results for the patient. These patients, previously implanted with hip prosthesis, have intrinsic limitations of hip joint ROM, sometimes associated with muscular impairments; therefore it’s rarely possible to bring back the hip to an optimal degree of function, especially if compared with a normal joint. The goodness of long-term results must be therefore evaluated in relation to patient’s conditions before the operation itself, especially according to bone conditions regarding osteointegration of prosthesis. If follow up of patient is constant, allowing to program with good timing the revision surgery, if necessary, the use of cementless prostheses is a very powerful (nevertheless conservative) instrument for good functional recovery of these patients.

The use of metal-on-metal THA has taken origin from the use of Mc Kee prostheses in our Institute in 1967. In 3rd Division of “Istituto Gaetano Pini” in Milan have been performed more than 1300 implants of these prostheses between 1967 and 1983. The analyses of implant surfaces after removal have demonstrated an almost null debris and good liability regarding implant stability. Even if someone assumed, in the past, the carcinogenic effects induced by metal debris, recent publications showed no statistically significant differences in the incidence of cancer between patients treated with metal-on-metal prostheses and normal population. The very good results in follow-up and the evidence of limited debris of metallic contact surfaces have encouraged us to continue with this experience using large head prostheses with metal-on-metal interface.

We implanted 73 Artek cup in 1997–2000 years, an uncemented pre-assembled cup, fixed by pure press fit. The advantages with this cup derived from his low profile (1/3rd of sphere) and contemporary use of large diameter heads (38 mm), similar to McKee’s model (35–41.5 mm). This design allowed us not only to preserve bone-stock, but even to reduce displacement risk. These advantages were increased by the absence of interposed PE surfaces, which inevitably suffer from time-related degeneration. In the last years we increase the use of hard surface THA, usually performing the implant of pressfit cups with metallic liner and large diameter heads (32 and 36 mm) or ceramic-ceramic interface. We believe in better indication (null-wear) of ceramic-ceramic THA in < 60 years patients (even in older ones high functional requests). Usually > 60 years we implant metal-on metal THA: we think that can guarantee very low debris rates and, if used in association with modular components and large diameter heads, a sensibly increased ROM and lower displacement rate.

We implanted 73 Artek cup in 1997–2000 years, an uncemented pre-assembled cup, fixed by pure pressfit. The advantages with this cup derived from his low profile (1/3rd of sphere) and contemporary use of large diameter heads (38 mm), similar to McKee’s model (35–41.5 mm). This design allowed us not only to preserve bone-stock, but even to reduce displacement risk. These advantages were increased by the absence of interposed PE surfaces, which inevitably suffer from time-related degeneration. In the last years we increase the use of hard surface THA, usually performing the implant of pressfit cups with metallic liner and large diameter heads (32 and 36 mm) or ceramic-ceramic interface. We believe in better indication (null-wear) of ceramic-ceramic THA in < 60 years patients (even in older ones high functional requests). Usually > 60 years we implant metal-on metal THA: we think that can guarantee very low debris rates and, if used in association with modular components and large diameter heads, a sensibly increased ROM and lower displacement rate.

The common use of hard surface THA has to be considered “gold standard” even in the elderly, in a constantly increasing mean-life era with corresponding better quality of life: we believe that is mandatory to offer, even to these patients, a long-lasting and high result hip arthroplasty.

The constant increase in number of hip revisions during last years has lead to a consequent increase even in fracturative events of the femoral shaft. The treatment of these kind of fractures have to be considered like the one for « pathologic fractures », due to periprosthetic or pericemental osteolysis that occurs in prosthesis’ mobilization, reducing drastically the bone resistance.

We use to divide these fractures primarily in two groups:

Pathologic Fractures, occurring before revision surgery.

Surgical solutions are different, according to fracture’s level and severity. TYPE 1 Fracture limited to trochanteric region TYPE 2 Fracture not exceeding stem length TYPE 3 Fracture line from shaft to distal part of the stem TYPE 4 Fracture line completely under femoral stem TYPE 5 Plurifragmentary fracture

For 1st group, surgical solution is to stabilize trochanteric region with dynamic wiring. For 2nd group, plate with both screws and dynamic wires are indicated. The fractures of last three groups are successfully treated with cementless long stem prosthesese, eventually associated with plate. In summary, the modern techniques of revision surgery associated with systems of cement removal (ultra-sounds and re-cementing procedures) have permitted to decrease the number of periprosthetic fractures. We think that the use of last generation models of cementless modular stem for revision, associated with dynamometric wiring, always allows brilliantly solving this complex surgical problem.