1) 82 patients with THA (40 who had at least one dislocation, and 42 matched patients without instability randomly selected, 19 of these 42 underwent a profile X-ray of the pelvis before and after THA insertion) 2) and 24 standard subjects who underwent lying and weight-bearing profile X-rays of the pelvis to assess the modifications of orientation of the pelvis between these two positions.
uncoated implants should be abandoned; HA resurfacing does not reduce the rate of revision and can be associated with a higher rage of osteolysis; there is no advantage between screw fixed or press-fit cups as long as the cup has a quality resurfacing; there is no real difference between straight and anatomic pivots except that intraoperative fracture can be lower for the straight implants.
Delayed sciatic nerve palsy is uncommon after primary hip replacement. Two kinds of sciatic palsy have been reported with regard to the time of onset: early palsy related to wound haematoma or lumbosacral nerve elongation which occurs between surgery and 18 days, is more frequent than delayed palsy, occurring between 10 and 32 months, which is usually caused by cement extrusion or heat produced by cement polymerisation. We present two cases of delayed, transient sciatic nerve palsy arising at three weeks and four months after primary cementless arthroplasty, respectively, without haematoma and with a normal lumbar spine. These palsies were possibly caused by excessive tension from minor limb lengthening of 2 cm to 4 cm required to achieve leg-length equality. As the initial symptoms were limited to calf pain and mild numbness in the foot, surgeons should be aware of this mode of onset, particularly when it is delayed after hip replacement. Both patients recovered fully by 12 months after surgery so we did not undertake surgical exploration of the nerve in either patient.
Thirty-nine cementless hip replacements using metal-on-metal articulation were consecutively implanted in thirty patients less than fifty years of age and compared with a matched control group of cementless replacements using ceramic-on-polyethylene articulation. The Harris hip score at follow-up (minimum five years) for the metal-on-metal was 94.9 (range, 74–100). After the same follow-up, the results of the ceramic-on-polyethylene were significantly worse: nine osteolyses and seven surgical revisions related to wear. Five-year survival rates were 97% +/− 2% for the ceramic-on-polyethylene and 100% for the metal-on-metal. The metal-on-metal may be recommended to prevent wear problems in younger and more active patients. The aim of the current study was to assess the results of metal-on-metal articulating components inserted as a primary hip replacement in patients under the age of fifty, comparated with a matched control group using ceramic-on-polyethylene. Patients and methods The inclusion of patients was: under fifty years of age and a diagnosis of arthrosis or necrosis of the femoral head. Femoral stem and cup migration was detected. A variation over five millimeters between the follow-up radiographs was considered as migration. At the follow-up in 2003, the cobalt concentrations in the whole blood were assessed in the metal-on-metal cohort. The detection limit of cobalt in the whole blood was 0.06 μg/L. None of the components had migration. At a mean follow-up of sixty-nine months, the median concentration of cobalt in the whole blood was 0.62μg/L. Only eight patients had cobalt levels greater than 1 μg/L. Considering a reoperation with the exchange of one of the components as end point, the five year survival rates were 100% for the metal-on-metal group and 97% + 2 for the ceramic-on-polyethylene group. Our study suggests that the metal-on-metal articulation gives a significant improvement in terms of resistance to wear when compared with these conventional bearing components. Our results suggest the metal-on-metal articulation with cementless components can be recommended in the young and active patient to prevent the occurrence of wear and osteolysis. A careful assessment of patients with high levels of whole-blood cobalt should be performed. Funding: Aucun