Purpose: Fracture of the neck of the femur in elderly subjects is generally treated by arthroplasty, either using a total or intermediary hip prosthesis, but with a high risk of dislocation, estimated at about 10% in the literature. We investigated the contribution of a double mobile cup to lower this risk.

Material and methods: This prospective study was conducted by several operators in the same university unit between 1998 and 2001. A total of 177 mobile prostheses were implanted in patients with fracture of the anatomic neck of the femur (n=145), the neck and trochanter (n=22), or pathologic fracture (n=4). For six patients, the prosthesis was implanted after failed osteosynthesis of a trochanteric fracture. The postero-lateral approach was used for 136 women and 41 men (age range 61 – 92 years) living at home (n=124), or in an institution with a high degree of independence (n=53). The femoral stem was cemented (n=115) or impacted (n=62). A double mobile cup was used in all cases. A chromium-cobalt/ polyethylene couple was used and head diameters were 28 mm (n=150) or 22.2 mm (n=27). We studied outcome and risk of dislocation one year after implantation.

Results: There were six deaths during the postoperative period. Among the 171 patients, 134 were seen at two months, 108 at six months and 89 at one year: 39 were questioned to ascertain outcome. During the first postoperative year, there were 37 deaths; these patients were followed. Six patients were lost to follow-up. We had two cases of intraprosthetic dislocation related to a defect in the chromium-cobalt head retention of the polyethylene insert. These two cases required revision and were reported to material surveillance with corrective measures for the manufacturer.

There were three true dislocations (2%): 1) a posterior dislocation on day 24 in a female patient presenting a fracture with impaction of the femoral stem; 2) a posterior dislocation on day 22 in a female patient in very poor general condition (severe cardiorespiratory failure, death at 48 hr); 3) one recurrent posterior dislocation related to major acetabular retroversion, revised at four months.

Discussion and conclusion: The double-mobile cup appears to be a simple reproducible method for preventing dislocation of prostheses implanted for fracture of the neck of the femur.

Purpose: We report an retrospective analysis of 33 patients with neurological para-osteo-arthroplathy of the hip who underwent surgery between 1985 and 1999.

Material and methods: Forty-three hips were operated in 33 patients aged 14 to 50 years at the time of the accident. Twenty-two patients had head trauma, two had spinal cord injury and three both. The causal mechanism was: trauma 27 patients, rupture of an inta-cranial aneurysm in five patients, widespread burns one patient. Localisations were inferome-dial 14 patients, anterior 10 patients, posterior two patients, circumferential five patients. Surgical care included complete resection in 30 cases, resection of the head and neck in six, and implantation of a total hip arthroplasty in seven. There were several perioperative accidents: two vessel injuries, two persistent bleedings, one haematoma, eight superficial infections, six recurrences, one ankylosis and one death. Functional outcome was assessed on the basis of gain in amplitude of hip flexion.

Results: Analysis was possible for 37 of the 43 hips. Outcome was good in 18 (flexion gain greater than 90°), fair in nine (flexion gain from 60 to 90°), poor in ten (flexion gain less than 60°). Complete resection gave better results (61.5%). Total hip arthroplasty gave mediocre results. The best results were obtained with resection for the inferomedial and anterior localisations.

Discussion: The decision for surgery should be discussed in light of the objectives to be achieved. We present our surgical strategy as a function of the localisation. We advocate systematic verification of the vascularisation and prefer the obturator approach for inferomedial localisations. The risk of recurrence depends on the delay from the accident to surgery.

Conclusion: Based on this retrospective series, we prefer surgical resection after the first year. We emphasise the importance of peroperative verification of the vascularisation.

Purpose: Among 80 surgical treatments for acetabular fracture, the Dana Mears approach was used in 15. The purpose of this study was to analyse functional and radiological outcome of these fractures at a mean follow-up of 41 months.

Material and methods: The AO classification was used for fractures of the acetabulum : 12 class B (80%) with five B1a2 five B2a1 and two B1a1, and three class C (20%). There was one deformed callus (B1a2) at 120 days Two patients had associated pelvic injuries, eight a hip dislocation, and two an initial sciatic palsy. There were also two osteochondral fractures of the femoral head. The Dana Mears approach was modified slightly in the anterior part passing in front of the tensor muscle to preserve innervation. The gluteal muscles were raised by trochanterotomy. The displacement, the head/ roof congruency and the head/acetabulum congruency were assessed according to the 1981 SOFCOT criteria on the initial x-rays (AP pelvis, oblique ala and obturator) and computed tomographies. The quality of the reduction was assessed with the Matta and Duquesnoy-Senegas criteria. Clinical results were assessed with the Postel Merle d’Aubigné (PMA) score.

Results: Radiographically, there was an anatomic reduction in 73.3% of the cases and perfect head/roof congruency in 80%. Functional outcome was excellent or good in 80% of the patients. Postoperative complications included 11 ossifications, and one transient sciatic paralysis. There was one late aseptic osteonecrosis of the femoral head.

Discussion: The functional prognosis of these fractures is significantly correlated with the quality of reduction (p < 0.05). The advantage of this approach is the direct access to the roof without disinsertion of the gluteal muscles from the iliac crest, allowing more rapid recovery (seven to eight months) of medius gluteus function. In principal drawback is the very high rate of ossifications (one patient required revision for arthrolysis).

Conclusion: The Dana Mears triradiate approach is an integral part of the surgical treatment of acetabular fractures, particularly for B1a2 and B2a1 fractures, but also for B1a1 transtectal fractures. Conversely, this approach is insufficient for reduction of type C fractures requiring and extensive access to the iliac wing and for surgery of deformed calluses where an endopelvic approach is indispensable to control the vessels.

Purpose: The anatomy of the endosteal canal of the proximal femur varies greatly in the general population. This variability can compromise total hip arthroplasty when a femoral stem is inserted without cement. While the secondary fixation of the implant is dependent on several parameters, the predominant factor is the primary stability and the large contact between the bone and the treatment surface of the apposed prosthesis. These two conditions, necessary but insufficient to guarantee an excellent clinical result, are obtained if there is a correct bone-implant morphology match. We analysed the morphology of the endosteal canal of the proximal femur to determine whether there is a standard anatomic conformation justifying the use of line prostheses.

Material and methods: We examined 30 femurs harvested from 30 individuals in a consecutive series in our anatomy laboratory. We made 12 scanner slices parallel to the knee joint line starting 1 cm above the apex of the lesser trochanter going up to 11 cm above the lesser trochanter. For each slice, we assimilated the canal to an ellipsoid surface to characterise its barycentre, the angle of the greater axis relative to the reference plane of the posterior condyles, and its dimensions defined with length (greater axis), and width (perpendicular to the greater axis).

Results: For each femur, the AP projections of the barycentres fell on a straight line (anatomic axis) and the lateral projections on a parabole. Helitorsion, i.e. the difference in the torsion angles between the first slice and the last slice was constant (57±8.5°). The dimensions were recorded for each slice.

Discussion: This method can be criticised. We were able to confirm the tridimensional data reported by Noble and confirmed the notion of a somatotype. We defined the normal (statistical) equation of the endosteal canal for the proximal end of the femur (barycentre, dimensions).

Conclusion: The anatomy of the endosteal canal of the upper extremity of the femur is not variable but standardised. It is thus possible to adapt the bone to the prosthesis.