The revision of the hip surgery belongs to the major orthopaedic surgery and the purpose of our research is the presentation of our experience.

During the period 2004–2008, revision in surgery of the hip was performed in 15 patients, while most of them were women with average 73 years. 190 subcapital fractures were revisioned in 7 patients, 277 pertrochanteric fractures in 3 patients, 75 total arthroplasties in 5 patients and all of them were bipolar arthroplasties and osteosynthesis with DSH plate. The average interval between the primary operation and revision arthroplasty was 28 months, revision of the acetabular was performed in 3, revision of the femoral in 1 and regarding to the other patients both types of revision were performed. According to Paprosky classification we noted lesions of type I and type II and in 13 cases operation was made in a time. Early complications appeared in 6 patients (mostly postoperative infections). For the stabilization of the acetabular we used supporting rings with bone grafts or press fit acetabulars without cement, while for the femoral, according to the injury extend and the bone quality, the stabilization of the stem was made with cement. The average follow-up time was 20 months, we re-examined 14/15 patients and chronic complications appeared in 2 patients. The final result was satisfactory, according to Harris-Hip score with the radiological evaluation.

Conclusively, hip revisions are difficult and demanding operations, accompanied by serious complications. For their success good preoperative planning, experience and complete material-technical supporting are required with use, most of the times, of custom made prosthesis, supporting rings of the acetabular with bone graft.

Periprosthetic fractures represent a challenging problem in joint arthroplasty the incidence of which seems to be increasing due to the big number of the arthroplasties and the increasing average life expectancy.

The purpose of this study is to present the methods of treatment, the problems that we have to solve intra-operatively and our long term results about the healing procedure and the fuctional restoration.

Between 2000–2008 we operated 15 femoral peri-prosthetic fractures(1 re-fracture). 10 of them were after hip arthroplasties.

The classification which used was Lewis-Rorabeck for the fractures after TKR and Vancouver for them after THA.

Cause of fracture was fall and the time interval from the primary operation was 1–14 years. The majority of the patients were women(14), and the mean age 65 years.

13 of the 15 fractures were treated with ORIF and the remaining two need to be revised. During the follow up 2 of them died due to other pathological problems. The post op follow up ranged from 1–8(3.5)years.

The postoperative evaluation was done according the Harris Hip Score and the Knee Society Clinical Rating System.

The fractures healed after a mean time of 6 months. Two postoperative wound infections were registered to the revised fractures and their treatment were successful with surgical debridement.

All the patients are in good health condition, moving with some kind of support and they are selfreserved.

As a conclusion we believe that this kind of fractures demand the proper surgical planning, prediction of all possible complications and the cooperation of other specialties and physiotherapisties.

Introduction: Cobalt-chrome particles from metal hip implants can accumulate in the liver, spleen, lymph nodes and bone marrow of patients. This is a concern as studies have reported neoplastic changes in cells of patients with metal implants. The aims of this study were to determine the effect of wear particles generated by metal-on-metal and ceramic-on-metal implants from hip simulations upon the viability of L929 cells and to determine their genotoxic potential when cultured with primary human fibroblasts.

Methods: Particles were generated in a 10 station Prosim hip simulator run with water as lubricant under microseparation and standard conditions. Bearings comprised medical grade HIPed ‘BIOLOX Forte’ alumina ceramic femoral heads against Ultima metal CoCr acetabular cups (CoM) and wrought CoCr alloy ASTM F1537 femoral heads and acetabular cups (MoM). Particles were sterilised at 1800C for 4 hours and cultured with L929 fibroblasts at particle volume(μm3):cell number ratios of 500:1, 100:1, 50:1, 5:1, 0.5:1, 0.05:1, 0.005:1 and 0.0005:1. Camptothecin (1 and 2μg.ml-1) and latex beads (100μm3 per cell) were used as positive and negative controls. Cultures were for 0, 1, 2, 3, 4 and 5 days at 37oC in 5%(v/v) CO2 in air. Cell viability was assessed using the ATPlite assay. Sterile particles were cultured with primary human fibroblasts at particle volume (μm3):cell number ratios of 50:1, 5:1 and 0.5:1. Cells were exposed to 30%(v/v) H2O2 (positive control) and latex beads (50μm3 per cell; negative control). Cells were cultured for 24 hours and 5 days at 37oC in 5%(v/v) CO2 in air. Genotoxicity was assessed using the comet assay. Statistical analysis between the cell-only negative controls and the cells with the particles at various concentrations, were determined by ANOVA and calculating the minimum significant difference (MSD;p< 0.05) using the T-method.

Results: Particle volume(μm3):cell ratios of 500:1, 100:1 and 50:1 caused a significant decrease in cell viability over 5 days. Wear particles from MoM implants under microseparation wear conditions were also significantly reduced viability at particle volume(μm3):cell ratios of 5:1 over 5 days. Particles from MoM implants under standard wear conditions and CoM implants under both wear conditions resulted in increases in tail length and tail moment relative to the cells only negative control for all treatment groups after 24 hours. These decreased by day 5. Tail length and tail moment were increased at 24 hours relative to day 5 for each of the three particle types. Particles generated by MoM implants under microseparation conditions had different effects upon cells. Tail lengths increased between days 1and 5 for all particle concentrations. A significant increase in tail moments between days 1 and 5 was recorded.

Discussion: This study has shown that metal particles can cause cytotoxic effects and immediate DNA damage to fibroblasts in vitro. Particles were found to reduce cell viability over 5 days and this may account for the decreases in tail length and moments between 1 and 5 days for three particle types. This is of concern as MoM and CoM implants are designed to be implanted into young patients and, despite their low wear rates generate circa 10¹³ particles per mm3 of wear.

Introduction: Joint replacement surgery is one of the most common operations that take place in United Kingdom. The major problem in total hip arthroplasty is the generation of particulate wear debris and the subsequent biological responses. Wear debris induces osteolysis and a subsequent failure of the implant that lead to the liberation of greater quantities of particulate and soluble debris to bone marrow, blood, lymph nodes, liver and spleen. Recently, it has been suggested that these adverse effects depend not only on the chemical composition but also on the particulate nature of the material (size and shape). Particle size has been shown to influence the inflammatory response of macrophages to wear debris. This study evaluated whether particle size also influences the viability and mutagenic damage.

Methods: Cobalt chrome alloy particles of two sizes (large 2.9±1.1μm, small 0.07±0.04 μm) were generated and characterised by Scanning Electron Microscopy. Different concentrations of particles were added to primary human fibroblasts in tissue culture. The release of cytokines in the medium was assayed by Enzyme-Linked ImunnoSorbent Assay (ELISA). Cell viability was determined by MTT conversion and the degree of DNA damage was quantitatively analysed by the Alkaline Single Cell Gel Electrophoresis (COMET) assay with image analysis.

Results: Small particles initialise DNA damage at much lower volumetric concentrations (0.05 and 0.5 μm³/cell) than larger particles (500 μm³/cell). The difference in the doses was approximately related to the difference in surface area of the particles. DNA damage was related to a delayed decrease in cell viability, which was noted after three days of exposure.

In contrast, the release of the inflammatory cytokine TNF-α and the multifunctional growth factor TGF-β-2 occurred at lower doses (0.0005 to 5 μm³/cell for TNF-α and 0.5 to 50 μm³/cell for TGF-β-2). No release of IL-6 was detected at any dose. Only growth factor FGF-23 was increased in similar pattern to the DNA damage.

Conclusions: This study has demonstrated important differences between the mutagenicity, toxicity and inflammatory potential of small (nanometre sized) and large (micrometer sized) chrome particles.

Wear debris from worn cobalt chrome joint replacements causes an increase in chromosomal translocations and aneuploidy. In this study the relationship between the amount of DNA damage and the changes in gene expression was investigated in human fibroblasts after exposure to artificial cobalt chrome particles. The comparison was made with different doses of particles, at different time intervals and in fibroblasts of different ages, those that had completed 10 population doublings (10 PD fibroblasts) and those that had completed 35 population doublings (35 PD fibroblasts). The genes (TGF-©¬2, p38 MAPK, Integrin ¥â1, SOD1, Caspase 10, PURA, FRA-1 and VNR) were chosen after a previous screen with cDNA microarrays. The percentage of senescent cells was evaluated using an immunohistochemical assay for ¥â-galactosidase activity. The 35 PD fibroblasts showed significantly more ¥â-galactosidase activity than the 10 PD fibroblasts. The level of DNA damage, as detected with the alkaline comet assay, was greater at higher doses, at longer exposures (up to 24 hours) and in 10 PD fibroblasts. The expression of all the genes listed above was generally lower after exposure to cobalt chrome particles using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The reduction in gene expression, like the increase in DNA damage was greater at higher doses and at longer exposure times. After 24hr exposure the reduction in gene expression was greater in 10 PD fibroblasts compared to 35 PD fibroblasts. After 6hr exposure this was only true at higher doses of particles and the opposite was seen after a lower dose of particles. These results show that levels of gene expression of TGF-©¬2, p38 MAPK, Integrin ¥â1, SOD1, Caspase10, PURA, FRA-1 and VNR may be correlated with the level of DNA damage and that this depends on the dose and length of exposure and the age of the cells. This highlights the potential importance of these genes in the mutagenicity of cobalt chrome particles in human fibroblasts.

The choice of the surgical exposure in total hip arthroplasties for osteoarthritis is a significant parameter for a successful outcome.

The aim of this study is to evaluate complications or/and advantages related to the most often used approaches for total hip arthroplasties: the direct lateral or transgluteal (Hardinge) and the posterior (Moore) one.

During the period 1997–2000, 50 patients with lateral approach and 50 patients with posterior approach were randomly selected from a pool of 394 total hip arthroplasties (382 patients). Patients with surgery of the contralateral hip were excluded. The mean age of the patients was 72 years (62–84 years) and the indication was degenerative osteoarthritis. The operating time and the postoperative, early and late, complications were studied. The average follow-up was 18 months (12–24 months) and included clinical and radiographic control.

The mean operating time was 76 min. (63–91 min.) and 92 min. (83–110 min.) for lateral and posterior approach, respectively. Complications (early and late) associated with transgluteal approach were 16 patients with positive trendelenburg sign, which disappeared within one year post op, 8 with sympathetic knee effusion which subsided within 6 weeks, 2 with ectopic periarticular ossification and 1 with severe thigh pain. In total hip arthroplasties with posterior approaches, 4 cases were complicated with ectopic ossification, 3 with sympathetic knee effusion which subsided within 4 weeks, 2 with posterior dislocation which needed revision surgery and 2 with peroneal nerve paresis which recovered within 6 months. Except for the trendelenburg sign (p< 0.001), all the other complications did not differ statistically significantly (p> 0.05).

In conclusion, the posterior approach seems to be related with more severe postoperative complications compared to the transgluteal approach. The gluteus medius’ loss of strength (responsible for limping in equal legs’ length), could be treated with prompt strengthening of the muscle within the first postoperative year.