INTRODUCTION

Since July 2008 we are experimenting a new cup with iliac screw fixation, developed on the idea of Ring and Mc Minn. Iliac fixation is permitted by a polar screw of large diameter, coated by HA, which allows a compression to bone and a firm primary stability. Moreover it's possible to increase primary stability with further smaller peripherals screws. We present this new cup and report the preliminary results.

The use of monoblock tapered stems has shown very good results in hip revision surgery, particularly in case of severe proximal femur bone deficiency.

However a too valgus neck, a short offset, may result in a high risk of dislocation. In addiction monoblock stems make the control of limb length difficult, and potentially increase the risk of subsidence or intraoperative fracture. Different types of modular tapered stems with distal fixation have been developed to allow a more user-friendly restoration of limb-lenght discrepancy and an indipendent proximal control of offset and anti-retroversion.

We assessed 64 hip revisions performed on 63 patients (mean age 62 years). Indication for treatment was: aseptic loosening (42 cases) septic loosening (18 cases) and periprosthetic fracture (4 cases). According to Paprosky classification, femoral defects were staged as type I (2 cases), type II (20 cases), type IIIA (25 cases) and type IIIB (13 cases); periprosthetic fractures were all type B2 according to the Vancouver classification. In all cases we used a Restoration® Modular (Striker, Orthopaedics) cone-conical uncemented stem implanted by a lateral approach, with a trans-femoral osteotomy in 19 cases. A preventive cerclage cable was used in 10 patients in case of very thin cortex. We used the minimum size stem in most of the cases.

Mean follow-up was 20 months (range 6–36). Short-term complications included hip dislocation (1 case), recurrent infection (1 case), stem subsidence > 5 mm (1 case). Mean Harris Hip Score improved from 43 to 81.9 (t test p< 0.0005), while limb lenght discrepancy improved in 97% of cases with symmetry in 76%.

The use of modular revision stems is an effective alternative in hip revision surgery that ensures good primary stability, while modularity enables the implant to be tailored to the patient, allowing restoration of the limb length and correct muscular balancing.

The vast majority of total-joint-replacement components utilized are modular to some degree. Modularity increases the surgeon’s options in both primary and revision THA. Modular prostheses allow the surgeon intra-operative versatility, allowing adjustment of leg length, offset, neck length, and version. This is particularly helpful in CHD, posttraumatic arthritis and in hip revision. Modularity may be applied also to the neck, enlarging the range of choice for difficult cases. Howeverusing of a modular interface increases risk of fretting, wear debris, and dissociation and mismatching of components.

A series of 87 revision THA performed between 1997 and 2003 using modular neck was reviewed. The pros-theses are AnCA-Fit with a cementless titanium anatomical stem and Profemur with a tapered revision titanium stem. Both provided with a modular neck inserted by morse taper and a hemispheric press-fitted cup. All the implants have a ceramic-ceramic coupling. Four cases were performed due to recurrent dislocation and 83 for implant loosening. Retrieved necks were studied searching for corrosion.

No cases of disassembly or fracture of the neck were observed. Two cases of dislocation were treated with brace. Analysis of retrieved necks confirmed the absence of corrosion. Leg length discrepancy decreased from 57.7% to 22%. One post-operative infection was successfully treated with debridment.

Modular neck system allows to correct intraoperatively leg length and offset, choosing between five interchangeable necks available in two lengths: straight, varus-valgus, ante-retroverted. Restoration of hip biomechanics prevents instability. Removal of the neck allows a better surgical exposure when femoral stem is retained. Moreover it allows to maintain ceramic-ceramic coupling. Modular prosthesis has some problems related to risk of corrosion, fretting, fracture or dislocation of components. We observed no cases of disassembly of components or fracture and comparative analysis between retrieved necks and those experimentally studied confirmed absence of corrosion.

From January 2003 to December 2004, 160 consecutive intertrochanteric hip fractures has been treated at the Orthopaedic Rizzoli Institute by a new short intra-medullary rod, which can be distally locked, combined with two sliding screws that insert into the femoral neck and head. The rod is an undersized, titan one. It can be inserted percutaneously.

Fractures were classified pre-operatively according to stability and post-operatively according to the type of operative reduction.

The failure rate and post-operative stability were then compared according to the type of fracture and to the quality of operative reduction.

Results indicate that the pre-operative fracture classification is a significant determinant of post-operative stability. The type of operative reduction was not as significant a determinant of post-operative stability, but an anatomical reduction gives better clinical results.

Overall results shows that stable fractures has always healed and only minor complications has been observed. Unstable fractures has a percentage of drawbacks of 1.5% (3 in 160 pts) due to a wrong screw positioning ( 2 proximal and 1 distal ).

Three patients died in the early post-operative period due to cardiac failure.

No intraoperative fracture, no displacement of the fracture site and no “cut out” were observed.

The uncemented cup with iliac stem ensures immediate primary stability by fixation to the hipbone in acetabular loosening with severe bone defect. Homologous bone grafts contribute to restoring bone stock, which is a fundamental requirement for long lasting implant stability.

From 2002 to 2004 we implanted 23 cups with iliac stems in 22 patients. In 7 cases there was also stem loosening, and so total hip arthroplasty was performed. In 2 patients the defect was grade 2b, in 5 grade 3a, and in 16 grade 3b according to Paprosky. A direct lateral approach was performed in the supine position. Morselized bone grafts were used in all cases by the “impaction grafting” technique, and in 4 cases modelled structural grafts were also employed. Mean follow-up has been 18 months (8–32).

So far we have not had any cases of loosening. At follow-up x-rays showed remodelling of the grafts with integration.

The cup with iliac stem enables primary stability on healthy bone tissue, and protects the grafts form mechanical stimulation, thus allowing them to integrate and restore bone-stock. It also restores the centre of rotation, and provides functional benefits and implant stability.

Aim Although converting a loosened fixation of the proximal femur into a total hip arthroplasty restores the joint, it is a technically complex operation and often requires steps that are not usually performed in arthroplasty for common diseases. The aim of this study was to assess clinical and radiographic results of 127 total hip arthroplasties due to loosening of proximal femur fixation, performed at our institute.

Materials and methods From 1987 to 2001 we performed 127 total hip arthroplasties (THA) in patients with loosened facture fixation of the proximal femur. Patients treated by endoprosthesis were excluded from this study.

The patients were divided into two groups according to the fracture site. Group 1 included 71 patients with medial fracture, and Group 2 contained 56 patients pertrochanteric or subtrochanteric fracture. All patients were assessed by the Merle d’Aubignè clinical evaluation method. Radiographically, the bone-implant interface was assessed by the presence of radiolucency lines according to the DeLee-Charnley method modified by Martell

Results The mean time lapse between fixation and conversion was 31 months for Group 1 and 10 months for Group 2 patients. In 12 cases of Group 2 bone grafts were used and surgery time was on average 20′ longer than that of Group 1. Furthermore, in Group 2, we had 4 dislocations compared to none in Group 1. In Group 2 long-stem prostheses with diaphyseal conical anchorage were more frequently used, whereas in Group 1 standard prostheses were used in all cases. Patients of Group 2 had a lower clinical score for the three parameters assessed (pain, walking and ROM) than those of Group 1. The final clinical results were also better for Group 1 patients.

Conclusions This study shows how THA in fixation loosening of proximal femur fractures can provide good results. Especially in patients with medial fractures of the femur, since the anatomy is not altered, THA does not pose any particular difficulties and ensures excellent results. In fractures of the trochanteric mass, where non-union or malunion alter markedly the anatomy of the bone segment, the site for the implant, results are certainly inferior However, careful planning of the operation, the use of special prostheses, and bone grafts enable satisfactory results to be achieved in these patients too.

Introduction Total hip arthroplasty in patients affected by major dysplasia poses great surgical difficulties due to insufficient primary acetabulum, small femoral canal, excessive anteversion of the femoral neck, traction on the neurovascular structures, muscular imbalance that is difficult to restore, and marked epiphyseal rising. In this study we present our experience in lowering and arthroplasty in major hip dysplasia, obtained by shortening osteotomy achieved in a single stage, using techniques designed to diminish possible risks.

Materials and methods From 1989 to 2000 we treated 20 patients (27 operations, 7 bilateral) at our institute who were affected by the sequela (lowering of the prosthesis) of Eftekhar Grade-C (11 cases) or Grade-D (16 cases) congenital luxation of the hip. Mean follow-up was 63 months. Clinical results were assessed before and after surgery according to the Merle D’Aubigné method. We also evaluated the presence and degree of Trendelenburg position and the possible use of shoe lifts. The radiographic results of the hip prosthesis were assessed by the Gruen and Dee Lee methods for the stem and cup respectively.

Results The mean preoperative clinical score according to the Merle D’Aubigné classification was 3 ± 1 for pain, 3 ± 1 for walking, and 4 ± 2 for movement. The preoperative Trendelemburg position was very marked in all patients. In 18 cases out of 27 a shoe lift was used with a mean height of 60 mm ± 10. We performed a “Z” osteotomy in 14 cases and an oblique osteotomy in 13 cases. The postoperative mean clinical score was 6 ± 1 for pain, 6 ± 1 for walking, and 5 ± 1 for movement. Postoperative Trendelemburg position was present in 19 cases, and 9 cases out of 27 still used a shoe lift with a mean height of 30 mm ± 10. Movement of the cup and stem was observed at 84 months and 112 months’ follow-up respectively, which required revision surgery.

Conclusions The choice between oblique and Z osteotomy depends on two parameters: the surgeon’s experience and the extent of femoral resection. Z osteotomy may be more difficult to perform technically, but it enables better adaptation of the prosthesis to the femoral segments for resections over 35 mm. No significant differences in time to unite were observed between oblique and Z osteotomies.