Risk of simultaneous and delayed breakage of total hip replacement ceramic implants in patients with trauma induced periprosthetic fracture and acetabular shell loosening.

Background: Ceramic implant breakage (CIB) in total hip replacement (THR) is a rare incident. A confusion exists between the fragile mechanical behaviour of ceramic materials (brittleness) and fragility in the common sense (easy to break), leading to the misconception that trauma is to blame for these breakages. Trauma has been reported as a cause of breakage by several authors and it is debated whether the burst force can be reached in one single trauma in-vivo.

Does load-bearing materials influence hip capsule thickness in total hip replacement? An MRI case-matched study.

Background: Ceramic-on-ceramic (COC) total hip replacements (THR) have exhibited less instability and late dislocation. Hip capsule plays an important role in hip stability. Different surrounding soft tissue reactions have been observed according to the bearing material used but no study compared these data using MRI investigation.

Total hip arthroplasty after acetabular fracture: does initial treatment make any difference to the outcome? A 5- to 23-year follow-up with clinical and radiological analysis.

Purpose: To determine if initial treatment affects the outcome of total hip arthroplasty (THA) after acetabular fracture.

Methods: 49 patients (49 hips) initially treated non-operatively followed some months later by THA in conjunction with acetabular reconstruction (Group 1) and 29 patients (29 hips) who had undergone THA after a previous osteosynthesis (Group 2) were assessed. The mean follow-up was 11.

Periprosthetic Joint Infection in Hip Arthroplasty: Is There an Association Between Infection and Bearing Surface Type?

Background: Preliminary studies have raised the question of whether certain prosthetic biomaterials used in total hip arthroplasty (THA) bearings are associated with increased risk of periprosthetic joint infection (PJI). For example, some observational data suggest the risk of PJI is higher with metal-on-metal bearings. However, it is not known whether other bearings-including ceramic bearings or metal-on-polyethylene bearings-may be associated with a higher or lower risk of PJI.

Ceramic-on-ceramic THA Implants in Patients Younger Than 20 Years.

Background: Poor survival of THA implants in very young patients has been attributed to use of cemented implants, wear of conventional polyethylene, and the presence of morphologic deformities in the proximal femur or in the acetabulum. Few studies have reported the long-term results of ceramic-on-ceramic implants in THAs in patients younger than 20 years.

Question/purposes: We determined: (1) the proportion of patients who experienced complications related to the ceramic bearing (squeaking, fracture); (2) the survivorship free from loosening and free from revision for any reason; (3) whether patients with osteonecrosis had inferior survivorship compared with patients whose surgical indication was all other diagnoses including sequelae of pediatric hip disorders (developmental dysplasia of the hip, Legg-Calvé-Perthes disease, slipped capital femoral epiphysis); and (4) clinical function.

Are ceramic-on-ceramic bearings in total hip arthroplasty associated with reduced revision risk for late dislocation?

Background: Dislocation is a major complication after primary total hip arthroplasty (THA), but little is known about the potential relationships between bearing materials and risk of dislocation. Dislocation within the first year after surgery is typically related to either surgical error or patient inattention to precautions, but the reasons for dislocation after the first year are often unclear, and whether ceramic bearings are associated with an increased or decreased likelihood of late dislocation is controversial.

Questions/purposes: The purpose of this study was to use a national registry to assess whether the choice of bearings-metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), ceramic-on-ceramic (CoC), or metal-on-metal (MoM)-is associated with differences in the risk of late dislocation.

Occurrence of noise in alumina-on-alumina total hip arthroplasty. A survey on 284 consecutive hips.

Background: Alumina-on-alumina bearings have been accepted as a valuable alternative for young and active patients. Alumina fractures, and socket loosening were the main complications reported. But, with the increasing number of prostheses implanted, noise occurrence appeared as a new concern.

Thirty years of experience with alumina-on-alumina bearings in total hip arthroplasty.

Alumina-on-alumina bearings in total hip arthroplasty have been developed in an attempt to minimise debris and the occurrence of osteolytic lesions. The outstanding tribological properties of this bearing system are explained by low surface roughness, high hardness for major scratch resistance, and high wettability. Since the 1970s, technological improvements in the manufacturing process of alumina components together with a better understanding of Morse taper technology have provided a surgical grade material with high density, high purity and small grains.

Is there a risk in placing a ceramic head on a previously implanted trunion?

Background: Strategies for revising a ceramic-on-ceramic total hip prosthesis are controversial. Some consider reimplantation of a ceramic head on a well-fixed femoral stem inadvisable as it may lead to a fracture of the newly implanted head.

Questions/purposes: We assessed (1) the risk of fracture when a new ceramic head was placed on a previously implanted trunion; (2) the survival rate of the revised hips; and (3) hip function and acetabular and femoral component loosening at midterm followup.

Cost analysis in total hip arthroplasty: experience of a teaching medical center located in Paris.

Background: Since the beginning of 2008, the implementation of a 100% activity-based payment system, has made efficiency one of the prime concern for the French health-care providing institutions. We therefore assessed the real cost of a scheduled total hip replacement (THR) ina teaching hospital and compared findings with French national data (and with the Government Healthcare Insurance System allowance).

Hypothesis: The study should suggest possible means to optimize organization of management and/or clinicians' practice.

Bone tissue response to titanium implant surfaces modified with carboxylate and sulfonate groups.

The present study assessed in vivo new bone formation around titanium alloy implants chemically grafted with macromolecules bearing ionic sulfonate and/or carboxylate groups. Unmodified and grafted Ti-6Al-4V exhibiting either 100% carboxylate, or 100% sulfonate, or both carboxylate and sulfonate groups in the percent of 50/50 and 80/20 were bilaterally implanted into rabbit femoral condyle. Neither toxicity nor inflammation were observed for all implants tested.

Decrease in particle-induced osteolysis in ovariectomized mice.

Postmenopausal osteoporosis is a common disorder that results from increased osteoclastic activity caused by estrogen deficiency. Whether postmenopausal bone remodeling can alter the response to particulate debris is unknown. The purpose of this study was to evaluate the bone response to polyethylene particles in an ovariectomized murine model.

[Total hip replacement: current concepts and basic issues].

Since the pioneering period of the early 1960s, total hip replacement has gained in safety, effectiveness and quality, through advances in anesthesia, pain control and less-invasive surgery. New materials have been developed jointly with engineers. Thirty years ago we started to develop a special friction system with alumina on an alumina couple, which avoids osteolysis due to plastic debris.

Benzylaminated dextran-modified hydrogels: a long-term bioactive TGF-beta1 carrier.

Highly porous dextran-based hydrogels [in which various amounts (up to 16.6%, w/w) of a benzylaminated dextran (DMCB) exhibiting high affinity for TGFbeta1 was immobilized] were developed to achieve long-term retention of bioactive TGFbeta1 in situ. Unmodified hydrogels rapidly desorbed 80-90% compared with only 40-60% of the preloaded TGFbeta1 from the DMCB-modified hydrogels during a period of 21 days in PBS in vitro.

Enhancement of the biological activity of BMP-2 by synthetic dextran derivatives.

In the present study, we explored the binding capacity of synthetic heparin-like dextran derivatives to recombinant human bone morphogenetic protein 2 (BMP-2), a heparin-binding osteoinductive growth factor. Affinity electrophoresis analysis provided evidence that carboxymethylated dextran polymers grafted with high amounts of benzylamide groups (named DMCB) interact with BMP-2. The capability of such polysaccharides to potentiate the growth factor biological activity was then investigated.

Alumina-on-alumina hip arthroplasty in patients younger than 30 years old.

Unlabelled: THA in patients younger than 30 years old presents challenges: the initial technical challenge relates to the initial disease that often causes deformities making reconstruction difficult, while the long-term challenge is wear and subsequent osteolysis and component loosening. Ceramic-on-ceramic prostheses may represent a valuable option to reduce wear. We retrospectively studied 101 patients (132 hips) with ceramic-on-ceramic prostheses implanted from 1977 to 2004.

Osteonecrosis after allogeneic bone marrow transplantation.

Unlabelled: Osteonecrosis after bone marrow transplantation is usually severe. Most patients develop acute and chronic graft-versus-host disease requiring a high dose of steroids for a long period of time. Generally ineffective nonoperative treatment in the past has resulted in treatment primarily with total hip arthroplasty (THA).

Prolonged hypoxia concomitant with serum deprivation induces massive human mesenchymal stem cell death.

Mesenchymal stem cells (MSCs) have been proposed for the repair of damaged tissue including bone, cartilage, and heart tissue. Upon in vivo transplantation, the MSCs encounter an ischemic microenvironment characterized by reduced oxygen (O2) tension and nutrient deprivation that may jeopardize viability of the tissue construct. The aim of this study was to assess the effects of serum deprivation and hypoxia on the MSC survival rates in vitro.

Engineering of implantable cartilaginous structures from bone marrow-derived mesenchymal stem cells.

Fabrication of implantable cartilaginous structures that could be secured in the joint defect could provide an alternative therapeutic approach to prosthetic joint replacement. Herein we explored the possibility of using biodegradable hydrogels in combination with a polyglycolic acid (PGA) scaffold to provide an environment propitious to mesenchymal stem cells (MSCs) chondrogenic differentiation. We examined the influence of type I collagen gel and alginate combined with PGA meshes on the extracellular matrix composition of tissue-engineered transplants.