Risedronate does not enhance fixation or BMD in revision cups: randomised study with three years follow-up.

Background: Bisphosphonates may improve implant fixation by inhibition of bone resorption and stimulation of osteoblasts by up regulation of BMP-2. However, there are few clinical studies in this area.

Questions/purpose: Does treatment with oral bisphosphonates improve implant fixation and bone remodelling around the acetabular component after revision arthroplasty with or without use of morselised allograft?

Patients And Methods: Fifty-three patients received university pharmacy blinded medication for three months: 5 mg risedronate or placebo one dosage and 1 g calcium carbonate and 800IE cholecalciferol per day.

Inducible displacements of the cup and the femoral head during active range of motion: dynamic RSA studies of cemented total hip replacements.

We evaluated changes in position of the femoral head relative to the cup and of the cup relative to the pelvis in total hip replacement patients during hip motion 2 years postoperatively. Two patient groups with nine patients in each group were studied. Hip motions, translations of the femoral head center, and cup displacements were recorded with dynamic radiostereometric examination (RSA, 2 exposures/s) during abduction in Group 1 and with use of static RSA exposures at increasing flexion of the hip in Group 2.

Femoral neck version affects medial femorotibial loading.

The aim of this study was to provide a preliminary evaluation of the possible effect that femoral version may have on the bearing equilibrium conditions developed on the medial tibiofemoral compartment. A digital 3D solid model of the left physiological adult femur was used to create morphological variations of different neck-shaft angles (varus 115, normal 125, and valgus 135 degrees) and version angles (-10, 0, and +10 degrees). By means of finite element modeling and analysis techniques (FEM-FEA), a virtual experiment was executed with the femoral models aligned in a neutral upright position, distally supported on a fully congruent tibial tray and proximally loaded with a vertical only hip joint load of 2800 N.

Highly crosslinked polyethylene does not reduce aseptic loosening in cemented THA 10-year findings of a randomized study.

Background: Polyethylene (PE) wear particles are believed to cause aseptic loosening and thereby impair function in hip arthroplasty. Highly crosslinked polyethylene (XLPE) has low short- and medium-term wear rates. However, the long-term wear characteristics are unknown and it is unclear whether reduced wear particle burden improves function and survival of cemented hip arthroplasty.

Five-year DEXA study of 88 hips with cemented femoral stem.

We performed repeated dual-energy X-ray absorptiometry (DEXA) measurements over five years in a homogeneous patient population to study the effect of a cemented stem on proximal femoral bone remodelling. Data from 88 patients (88 hips) implanted with total hip arthroplasty (THA) prostheses were extracted from three randomised studies. Femoral bone mineral density (BMD) was measured using a Lunar DPX-IQ densitometer for five years postoperatively.

Anticonvulsant drug-induced rickets and multiple slipped epiphyses in a child treated non-operatively: a case report.

The clinical and radiographic presentation of a child with spastic tetraplegia, anticonvulsant drug-induced rickets, borderline hypothyroidism and multiple slipped epiphyses is described. While the metabolic abnormalities were being treated, the parents denied surgical treatment and have been non-compliant with bracing of the wrist, ankle and knee deformities. By two years of medical treatment, rickets had resolved and the growth plates of the lower limbs' joints had closed.

5-year experience of highly cross-linked polyethylene in cemented and uncemented sockets: two randomized studies using radiostereometric analysis.

Background: Laboratory tests and early clinical studies have shown that highly cross-linked polyethylene (PE) markedly improves wear resistance compared to conventional PE. We evaluated this type of PE in two randomized clinical studies using radiostereometric analysis (RSA). The 2- and 3-year follow-up of these studies have already been reported.

Influence of design variations on early migration of a cemented stem in THA.

Unlabelled: The clinical results of using different cemented stems in total hip arthroplasty may vary because of shape, surface finish, and choice of metal alloy. Less is known about the influence of size and offset using one and the same design. Data from 140 patients (140 hips) of a cohort constituting 197 patients (231 hips) implanted with cemented Spectron Primary stems were extracted from patients studied in four randomized studies primarily designed for other purposes.

Addition of fluoride to acrylic bone cement does not improve fixation of a total hip arthroplasty stem.

Unlabelled: Improved fixation to bone is vital for improving the long term success of cemented implants. Addition of fluoride to acrylic bone cement may be one way to improve the quality of the bone cement interface and thereby reduce the risk of loosening. Ninety patients (97 hips) with a median age of 70 years (range, 31-81 years) scheduled for total hip arthroplasty were randomized to receive a stem fixed with fluoride-containing acrylic bone cement or conventional acrylic bone cement.

Standing versus supine radiographs in RSA evaluation of femoral head penetration.

Evaluation of polyethylene acetabular component wear in total hip arthroplasties commonly is performed using serial radiographs of the hip by measuring the change in the location of the center of the femoral head in relation to the acetabular component. Of the different methods currently used for this purpose, radiostereometric analysis (RSA) is considered the most accurate and precise. In all such radiographic studies, it is assumed the femoral head is seated into the deepest portion of the acetabular component during all radiographic examinations.

Different loss of BMD using uncemented press-fit and whole polyethylene cups fixed with cement: repeated DXA studies in 96 hips randomized to 3 types of fixation.

Background: In cemented THA, aseptic loosening of the cup is more common than loosening of the stem, while periprosthetic osteolysis of the socket resulting in difficult reconstruction problems has emerged as the most significant problem with cementless cup fixation.

Patients And Methods: 90 patients (96 hips) scheduled for THA were stratified in three groups according to the method of fixation of the acetabular component: acrylic bone cement with fluoride (Cemex-F), porous-coated press-fit cup with ceramic coating (Trilogy, uncemented) and acrylic cement with gentamicin (Palacos). All patients received the Spectron EF stem.

Fluoride-containing acrylic bone cement in total hip arthroplasty. Randomized evaluation of 97 stems using radiostereometry and dual-energy x-ray absorptiometry.

Ninety patients (97 hips) scheduled for total hip arthroplasty were stratified to fixation of the femoral component using fluoride-containing cement or Palacos with gentamicin. Whole polyethylene Reflection and press-fit Trilogy cups were used. All patients received Spectron EF stem.

New polymer materials in total hip arthroplasty. Evaluation with radiostereometry, bone densitometry, radiography and clinical parameters.

Aims: To evaluate the outcome of different types of polyethylene, bone cements and one design of uncemented fixation with porous and ceramic coating using radiostereometry, bone densitometry, conventional radiography and clinical parameters.

Materials And Methods: Study I: 201 patients were extracted from 5 prospective randomised studies to evaluate femoral head penetration at two years with radiostereometry in four basic designs, cemented Lubinus and Reflection cups, uncemented Trilogy and Reflection cups. Studies II and III: 60 patients (61 hips) were randomised to receive either highly cross-linked or conventional all PE cups.

The Otto Aufranc Award. Highly cross-linked polyethylene in total hip arthroplasty: randomized evaluation of penetration rate in cemented and uncemented sockets using radiostereometric analysis.

The annual wear rate in polyethylene articulations should be 0.1 mm or less to avoid future osteolysis. Highly cross-linked polyethylene shows an 80 to 90% wear reduction in hip simulator testing, but the clinical documentation of this new polyethylene is still inadequate.

Bioactive cement or ceramic/porous coating vs. conventional cement to obtain early stability of the acetabular cup. Randomised study of 96 hips followed with radiostereometry.

Ninety patients (96 hips) scheduled for THA were stratified to fixation of the acetabular component in three main groups of about equal size. Fluoride cement, porous coated press-fit cup with ceramic coating or Palacos cum Gentamicin cement were used. All patients received Spectron EF stem.

Highly cross-linked polyethylene in cemented THA: randomized study of 61 hips.

Highly cross-linked polyethylene (PE) has been introduced as an alternative bearing material in total hip arthroplasty (THA) because of high wear resistance in laboratory tests but the clinical experience of this material is limited. We evaluated a highly cross-linked PE (warm irradiated adiabatic melting, absorbed dose, 95 kGy) in a randomized study of cemented THAs. Cups of the same design but made of conventionally gamma irradiated PE (absorbed dose, 25-40 kGy) constituted the control group.

Increase in early polyethylene wear after sterilization with ethylene oxide: radiostereometric analyses of 201 total hips.

We evaluated polyethylene wear by measuring femoral head penetration in 201 THA (median age 62 (31-81) years, 117 women) extracted from 5 randomized studies aimed to assess various fixation principles. There were 30 cemented all-polyethylene Lubinus cups sterilized by gamma irradiation in a reduced oxygen environment, 65 porous-coated Trilogy cups with liners gamma-sterilized in inert gas. Moreover, 37 cemented cups were sterilized with ethylene oxide (Reflection all-poly) and 69 porous-coated cups had liners sterilized in ethylene oxide (Reflection).