Prosthetic joint infections (PJI) occur infrequently, but they represent the most devastating complication with high morbidity and substantial cost. Staphylococcus aureus and coagulase-negative S. epidermidis are the most common infecting agents associated with PJI.

During the past decades, novel materials have been developed to improve osseointegration of implants. Recently has been demonstrated that by using nanosized hydroxyapatite (HA) coatings, since it combines nanoroughness and bone-like chemistry in a synergistic effect, it promotes better osseointegration when compared to uncoated metal implants. In a further step, due to the known bactericidal properties of fluor, the aim of this study is to evaluate the biofilm development on fluorohydroxyapatite (FHA) compared to HA.

Coatings were grown on stainless steel substrates by Pulsed Laser Deposition (PLD) technique using fluorohydroxyapatite targets of marine origin. A comprehensive physicochemical characterization of the coatings was performed using SEM, EDS, XPS and XRD. Biological in vitro tests using the pre-osteoblastic cell line (MC3T3-E1) demonstrated the non-cytotoxicity of FHA coatings, the healthy cell proliferation and their osteogenic activity.

The S. aureus 15981 (Valle et al.) and S. epidermidis ATCC 35984 strains adherence study was performed introducing each probe in a well of 96-well plate with 200 µl containing 106 colony forming units (CFU/mL) intryptic soy broth supplemented with 1% glucose and was incubated at 37°C 5% CO2 for 24 hours. After incubation, the medium was removed and three washes with 0.9% NaCl sterile saline were performed. The biofilm was disrupted by sonication at 50–60 Hz for 5 min. The CFU/cm2 was estimated by drop plate method. All of the experiments were performed in triplicate.

Statistical analysis was performed by non-parametric unilateral Wilcoxon”s test with a level of statistical significance of 0.05.

The results showed a significant (p=0.02475) 2.4-fold reduction in S. epidermidis biofilm formation on FHA (logUFC/cm2 = 6.87) compared to HA (logUFC/cm2 = 7.25); and also a significant (p=0.042) 3.7-fold reduction in S. aureus 15981 biofilm formation.

In conclusion, according our results FHA is a promising biomaterial that promotes osseointegration and decreases the staphylococcal biofilm that could avoid PJI. Further studies will be necessary.

Introduction and Objectives: Sinding-Larsen-Johansson (SLJ) syndrome is a frequent entity in which there is pain on the anterior aspect of the patella in young athletes. Its etiopathogenesis is not well defined and it is considered a traction apophysitis. Our objective was to analyze the association of SLJ syndrome with the presentation of elevated patella.

Materials and Methods: We carried out a prospective study of 15 knees with evident clinical and radiological signs of SLJ syndrome and another 15 knees without any previous pathological condition. We used X-rays to measure the Caton-Deschamps index, the modified Insall index, and the posterior angle of inclination of the proximal surface of the tibia; we also took clinical measurements of the popliteal angle.

Results: We studied 15 knees in 14 patients. The percentage of males was 85.7% and the mean age of appearance of this pathological condition was 10.86 years (+/− 1.61) Analysis of the data shows that there were no significant differences (p> 0.5) between the groups in relation to the Caton index and the modified Insall index. In relation to the measurements of the popliteal angle of damaged knees, we did find significant differences (mean value: 32.50 d.t.:8.90) with reference to the control group (mean value: 17.67 (+/−. 8.21), and the same was true for the measurements of the posterior inclination angle (mean value: 10.47 (+/− 2.82) in comparison with the knees of the control cases (mean value: 8.33 (+/− 1,40).

Discussion and Conclusions: In conclusion, we found a statistically significant relationship between SLJ syndrome and shortening of the hamstring and increase in the posterior angle of inclination of the tibia.

INTRODUCTION: In guided tissue regeneration a membrane is used for defect isolation to protect it against invasion from surrounding tissues and to keep intrinsic healing factors ‘in situ’. This technique has been successfully used in maxillo-facial surgery, but short experience has been reported in long-bone defects, with synthetic membranes and with variable results. In the other hand, calcification and ossification inside the arterial wall have been described.

OBJECTIVE: The aim of the study was to evaluate the use of cryopreserved aorta allografts as membranes for guided tissue regeneration in comparison with expanded poly-tetra-fluoro-ethylene (e-PTFE) synthetic membranes.

MATERIAL & METHODS: Prospective, randomized, blinded study in 15 New-Zeland rabbits. 10 mm mid-diaphyseal defects were created in both radii: 10 defects were covered with a cryopreserved aortic allograft as a tube, 10 with an e-PTFE membrane and 10, with no barrier membrane, served as controls. Animals sacrifice at 6–12–24–30 months. Studies: X-rays, CT, MR, morpho-densitometric analysis, electronic and optical microscopy. Immuno-cytochemistry on tissues and arterial wall cells cultured.

RESULTS: None of the control defects healed. Nine defects covered with an artery completely reconstituted, but only six of those covered with e-PTFE, with a nearly normal cortical-medullar pattern and with progressive increasing in density and thickness of medullar and cortical to values similar to those of the normal bone. Histological studies showed no inflammatory response to the arterial graft, direct union between the artery and the regenerated bone and even mature bone between the elastic laminae of the arterial wall, suggesting superior biocompatibility properties. Immuno-cytochemistry and ultrastructural studies suggest that arterial allografts could act not only as membrane barriers, with additional osteoinductive properties due to trans-differentiation of viable arterial wall cells (endothelial, smooth muscle and/or tissue specific stem cells) towards osteoblastic cells, and also due to ossification secondary to changes in proteins of the arterial extracellular matrix. This could be the application of the process of arterial wall calcification and ossification (usually seen in arteriosclerosis, gender, diabetes or kidney failure) for regeneration of long-bone defects.

CONCLUSION: Cryopreserved aortic allografts can be used as membrane barriers for guided bone regeneration, with superior results to e-PTFE membranes.

We have studied the medium- and long-term effects of femoral intramedullary nailing in 34 children. There was a high incidence of abnormality at the proximal end of the femur, including coxa valga, arrest of growth of the greater trochanter and thinning of the neck of the femur, because of damage to the trochanterocervical growth plate. These disorders affected 30% of the patients, mostly under the age of 13 years (p < 0.05), and were seen more frequently when the nail had been introduced through the piriform fossa. Other factors, such as the side, gender, aetiology, proximal or retrograde insertion, the size of nail and removal of the implant did not influence the result. We recommend that in patients under the age of 13 years other methods of management should be used to avoid damage to the growth plate.