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Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_2 | Pages 113 - 113
2 Jan 2024
García-Rey E Gómez-Barrena E
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Pelvic bone defect in patients with severe congenital dysplasia of the hip (CDH) lead to abnormalities in lumbar spine and lower limb alignment that can determine total hip arthroplasty (THA) patients' outcome. These variables may be different in uni- or bilateral CDH.

We compared the clinical outcome and the spinopelvic and lower limb radiological changes over time in patients undergoing THA due to uni- or bilateral CHD at a minimum follow-up of five years.

Sixty-four patients (77 hips) undergoing THA due to severe CDH between 2006 and 2015 were analyzed: Group 1 consisted of 51 patients with unilateral CDH, and group 2, 113 patients (26 hips) with bilateral CDH. There were 32 females in group 1 and 18 in group 2 (p=0.6). The mean age was 41.6 years in group 1 and 53.6 in group 2 (p<0.001). We compared the hip, spine and knee clinical outcomes. The radiological analysis included the postoperative hip reconstruction, and the evolution of the coronal and sagittal spinopelvic parameters assessing the pelvic obliquity (PO) and the sacro-femoro-pubic (SFP) angles, and the knee mechanical axis evaluating the tibio-femoral angle (TFA).

At latest follow-up, the mean Harris Hip Score was 88.6 in group 1 and 90.7 in group 2 (p=0.025). Postoperative leg length discrepancy of more than 5 mm was more frequent in group 1 (p=0.028). Postoperative lumbar back pain was reported in 23.4% of the cases and knee pain in 20.8%, however, there were no differences between groups. One supracondylar femoral osteotomy and one total knee arthroplasty were required. The radiological reconstruction of the hip was similar in both groups. The PO angle improved more in group 1 (p=0.01) from the preoperative to 6-weeks postoperative and was constant at 5 years. The SFP angle improved in both groups but there were no differences between groups (p=0.5). 30 patients in group 1 showed a TFA less than 10º and 17 in group 2 (p=0.7).

Although the clinical outcome was better in terms of hip function in patients with bilateral CDH than those with unilateral CDH, the improvement in low back and knee pain was similar. Patients with unilateral dysplasia showed a better correction of the PO after THA. All spinopelvic and knee alignment parameters were corrected and maintained over time in most cases five years after THA.


Bone & Joint Research
Vol. 11, Issue 12 | Pages 881 - 889
1 Dec 2022
Gómez-Barrena E Padilla-Eguiluz N López-Marfil M Ruiz de la Reina R

Aims

Successful cell therapy in hip osteonecrosis (ON) may help to avoid ON progression or total hip arthroplasty (THA), but the achieved bone regeneration is unclear. The aim of this study was to evaluate amount and location of bone regeneration obtained after surgical injection of expanded autologous mesenchymal stromal cells from the bone marrow (BM-hMSCs).

Methods

A total of 20 patients with small and medium-size symptomatic stage II femoral head ON treated with 140 million BM-hMSCs through percutaneous forage in the EudraCT 2012-002010-39 clinical trial were retrospectively evaluated through preoperative and postoperative (three and 12 months) MRI. Then, 3D reconstruction of the original lesion and the observed postoperative residual damage after bone regeneration were analyzed and compared per group based on treatment efficacy.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_3 | Pages 9 - 9
1 Apr 2018
Garcia-Rey E Carbonell R Cordero J Gomez-Barrena E
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Introduction

Durable bone fixation of uncemented porous-coated acetabular cups can be observed at a long-term, however, polyethylene (PE) wear and osteolysis may affect survivorship. Accurate wear measurements correlated with clinical data may offer unique research information of clinical interest about this highly debated issue.

Objetive

We assessed the clinical and radiological outcome of a single uncemented total hip replacement (THR) system after twenty years analysing polyethylene wear and the appearance of osteolysis.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_9 | Pages 77 - 77
1 May 2017
García-Rey E Gómez-Barrena E García-Cimbrelo E
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Background

Although the tribological characteristics are excellent, cup fixation has been one of the limitations in alumina-on-alumina total hip replacement (THR), so different types of materials and surfaces have been developing. We analysed the clinical and radiological outcome of two different uncemented cups for the same alumina-on-alumina THR.

Methods

679 hips were prospectively followed for at least 5 years. 342 had a hydroxyapatite (HA)-coated relatively smoothed tri-radius cup, implanted between 1999 and 2005 (group 1), and, 337 had a HA-coated macotextured tri-radius implanted between 2006 and 2009 (group 2). Dysplastic hips were more frequently observed in group 2. We compared screw use in both groups as primary fixation, the clinical results, and the radiological appearance of cup loosening.


Bone & Joint Research
Vol. 6, Issue 5 | Pages 315 - 322
1 May 2017
Martinez-Perez M Perez-Jorge C Lozano D Portal-Nuñez S Perez-Tanoira R Conde A Arenas MA Hernandez-Lopez JM de Damborenea JJ Gomez-Barrena E Esbrit P Esteban J

Objectives

Implant-related infection is one of the most devastating complications in orthopaedic surgery. Many surface and/or material modifications have been developed in order to minimise this problem; however, most of the in vitro studies did not evaluate bacterial adhesion in the presence of eukaryotic cells, as stated by the ‘race for the surface’ theory. Moreover, the adherence of numerous clinical strains with different initial concentrations has not been studied.

Methods

We describe a method for the study of bacterial adherence in the presence of preosteoblastic cells. For this purpose we mixed different concentrations of bacterial cells from collection and clinical strains of staphylococci isolated from implant-related infections with preosteoblastic cells, and analysed the minimal concentration of bacteria able to colonise the surface of the material with image analysis.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_8 | Pages 78 - 78
1 Apr 2017
García-Rey E García-Cimbrelo E Gómez-Barrena E
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Background and aim

Recent proposals have been introduced to modify stem design and/or femoral fixation in total hip replacement (THR). New designs need to consider previous design features and their results. The aim of this study has been to evaluate the clinical and radiological results of six different designs of tapered uncemented stems implanted in our Institution.

Methods

1918 uncemented hips were prospectively assessed from 1999 to 2011 (minimum follow-up of five years for the unrevised hips). All hips had a 28 or 32 mm femoral head and metal-on-polyethylene or alumina-on-alumina bearing surface. Six uncemented femoral designs that shared a femoral tapered stem incorporating a coating surface were included in the study. The different design features included the type of coating, metaphyseal filling, and sectional shape.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_8 | Pages 35 - 35
1 Apr 2017
Ciapetti G Fotia C Granchi D Rojewski M Rosset P Gómez-Barrena E Baldini N
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Background

Delayed bone healing and nonunion are complications of long bone fractures, with prolonged pain and disability. Regenerative therapies employing mesenchymal stromal cells (MSC) and/or bone substitutes are increasingly applied to enhance bone consolidation. Within the REBORNE project, a multi-center orthopaedic clinical trial was focused on the evaluation of efficacy of expanded autologous bone marrow (BM) derived MSC combined with a CaP-biomaterial to enhance bone healing in patients with nonunion of diaphyseal fractures. To complement the clinical and radiological examination of patients, bone turnover markers (BTM) were assayed as potential predictors of bone healing or non-union.

Methods

Bone-specific alkaline phosphatase (BAP), C-terminal-propeptide type I-procollagen (PICP), osteocalcin (OC), β-Cross-Laps Collagen (CTX), soluble receptor activator of NFkB (RANKL), osteoprotegerin (OPG) were measured by ELISA assays in blood samples of 22 patients at BM collection and at follow-ups (6, 12 and 24 weeks post-surgery).


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_8 | Pages 39 - 39
1 Apr 2017
Gomez-Barrena E Rosset P Hernigou P Gebhard F Ehrnthaller C Baldini N Layrolle P
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Background

Definitive proof is lacking on mesenchymal stem cell (MSCs) cellular therapy to regenerate bone if biological potential is insufficient. High number of MSCs after GMP expansion may solve the progenitor insufficiency at the injury but clinical trials are pending.

Methods

A prospective, multicenter, multinational Phase I/IIa interventional clinical trial was designed under the EU-FP7 REBORNE Project to evaluate safety and early efficacy of autologous expanded MSCs loaded on biomaterial at the fracture site in diaphyseal and/or metaphysodiaphyseal fractures (femur, tibia, humerus) nonunions. The trial included 30 recruited patients among 5 European centres in France, Spain, Germany, and Italy. Safety endpoints (local and general complication rate) and secondary endpoints for early efficacy (number of patients with clinically and radiologically proven bone healing at 12 and 24 weeks) were established. Cultured MSCs from autologous bone marrow, expanded under GMP protocol was the Investigational Medicinal Product, standardised in the participating countries confirming equivalent cell production in all the contributing GMP facilities. Cells were mixed with CE-marked biphasic calcium phosphate biomaterial in the surgical setting, at an implanted dose of 20−106 cells per cc of biomaterial (total 10cc per case) in a single administration, after debridement of the nonunion.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_3 | Pages 130 - 130
1 Feb 2017
Garcia-Rey E Cimbrelo EG Gomez-Barrena E
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Background and aim

Despite good survivorship analysis for most uncemented tapered straight stems, new proposals modifying stem design in total hip replacement (THR) are being introduced in order to facilitate femoral revision surgery.

We have evaluated the clinical and radiological results of four different designs of uncemented tapered straight stems implanted in our institution in order to assess: operative complications, clinical results, survivorship analysis for aseptic loosening and radiographic findings

Methods

1008 hips implanted from 1998 to 2006 were prospectively followed for a mean of 12 years (range, 10 to 17). Four uncemented femoral designs employing a tapered straight stem were included: 209 Alloclassic stems, 420 Cerafit, 220 SL-Plus and 159 Summit. All hips had a 28 or 32 mm femoral head, and polyethylene (PE)-on metal or ceramic-on-ceramic bearing surface. Radiological femoral type, stem position, femoral canal filling at three levels and the possible appearance of loosening and other bone remodelling changes were recorded in all hips.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_2 | Pages 56 - 56
1 Jan 2017
García-Rey E Gómez-Barrena E García-Cimbrelo E
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Total hip replacement (THR) in young patients has been associated to higher revision rates than in older population. Different conditions may lead to end-stage arthritis of the hip in these patients. We compared the clinical and radiological outcome of two different groups of young and very young patients who underwent a ceramic-on-ceramic THR.

120 hips were prospectively followed for a mean of 10.4 years (range, 5 to 17). 38 patients (46 hips) were less than 30 years old (group 1), and, 68 (74 hips) were between 31 and 40 years old (group 2). Weight (p<0.001) and physical activity level were greater in group 2 (p<0.001). Preoperative function (p=0.03) and range of mobility (p=0.03) were worse in group 1. Primary osteoarthritis was not found in any case. Rheumatoid juvenile arthritis was the most frequent diagnosis in group 1 and avascular necrosis of the femoral head in group 2. A femoral funnel-shaped type 1 according to Dorr was more frequent in group 2 (p=0.04). The same ceramic-on-ceramic uncemented THR was used in all cases. Screws for cup fixation were only used when strictly needed. We analysed the clinical results according to the Merle-D´Aubignè and Postel scale, the postoperative radiological reconstruction of the hip and the radiological appearance of cup loosening. Kaplan-Meier survivorship analysis was used to estimate the cumulative probability of not having a revision surgery.

Screw use required to obtain a secured interference fit of the acetabular component was found more frequently in group 1 (p=0.01). Postoperative pain (p=0.002) and function (p=0.002) were better in group 1. Mean acetabular abduction angle of the cup was greater in group 1 (p=0.03) and reconstruction to the hip rotation center according to Ranawat (p=0.01) was better in group 2. Placement of the acetabular component inside the Lewinnek´s zone and stem position were similar in both groups. No hips were revised due to complications related to ceramic or to stem loosening. Three cups were revised for aseptic loosening in group 1 and four in group 2. The survival rate for cup aseptic loosening at 15 years was 92.3% (95% CI: 83.7 to 100) for group 1 and 93.1% (95% CI: 85.3 to 99.9) for group 2 (Log rank, p=0.88).

Ceramic-on-ceramic uncemented THR is an excellent option for young and very young patients. Despite worse preoperative conditions in patients under the age of 30 years, a similar clinical outcome was found in this series.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_2 | Pages 55 - 55
1 Jan 2017
García-Rey E Gómez-Barrena E
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Although cemented fixation provides excellent results in primary total hip replacement (THR), particularly in patients older than 75 years, uncemented implants are most commonly used nowadays. We compare the rate of complications, clinical and radiological results of three different designs over 75-years-old patients.

433 hips implanted in patients over 75 years old were identified from our Local Joint Registry. Group A consisted of 139 tapered cemented hips, group B of 140 tapered grit-blasted uncemented hips and group C of 154 tapered porous-coated uncemented hips. A 28 mm femoral head size on polyethylene was used in all cases. The mean age was greater in group A and the physical activity level according to Devane was lower in this group (p<0.001 for both variables). Primary osteoarthritis was the most frequent diagnoses in all groups. The radiological acetabular shape was similar according to Dorr, however, an osteopenic-cylindrical femur was most frequently observed in group A (p<0.001). The pre- and post-operative clinical results were evaluated according to the Merle-D'Aubigne and Postel scale. Radiological cup position was assessed, including hip rotation centre distance according to Ranawat and cup anteversion according to Widmer. We also evaluated the lever arm and height of the greater trochanter distances and the stem position. Kaplan-Meier analysis was done for revision for any cause and loosening.

The hip rotation centre distance was greater and the height of the greater trochanter was lower in group B (p=0.003, p<0.001, respectively). The lever arm distance was lower in group C (p<0.001). A varus stem position was more frequently observed in group B (p<0.001). There were no intra- or post-operative fractures in group A, although there were five intra-operative fractures in the other groups plus two post-operative fractures in group B and four in group C. The rate of dislocation was similar among groups and was the most frequent cause for revision surgery (8 hips for the whole series). The mean post-operative clinical score improved in all groups. The overall survival rate for revision for any cause at 120 months was 88.4% (95% CI 78.8–98), being 97.8% (95% CI 95.2–100) for group A, 81.8% (95% CI 64.8–98.8) for group B and 95.3% (95% CI 91.1–99.6) for group C (log Rank: 0.416). Five hips were revised for loosening. The overall survival rate for loosening at 120 months was 91.9% (95% CI 81.7–100), being 99.2%(95% CI 97.6–100) for group A, 85.5 (95% CI 69.9 −100) for group B and 100% for group C (Log Rank 0.093).

Despite a more osteopenic bone in the cemented group, the rate of peri-prosthetic fractures was higher after uncemented THR in patients older than 75 years. Although the overall outcome is good with both types of fixation, the post-operative reconstruction of the hip, which might be more reliable after cemented fixation, may affect the rate of complications in this population.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 290 - 290
1 Jul 2014
Calzado-Martín A Crespo L Saldaña L Boré A Gómez-Barrena E Vilaboa N
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Summary

Attachment, proliferation and osteogenic maturation of hMSCs are enhanced on a sub-micron grooved Ti6Al4V alloy, while osteoblasts are less sensitive. These effects are attributed to their different maturation stage and may be mediated through differential activation of the RhoA/ROCK pathway.

Introduction

Ti6Al4V alloy is the most widely used titanium-based biomaterial for manufacturing bone-anchoring devices. We report on the interactions of human bone-forming cells, mesenchymal stem cells from bone marrow (hMSCs) and primary osteoblasts (hOBs), with an anisotropic Ti6Al4V alloy that displays submicron grooves.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 33 - 33
1 Jul 2014
Perez-Jorge C Perez-Tanoira R Lozano D Conde A Arenas M Hernandez-Lopez J De-Damborenea J Gomez-Barrena E Esbrit P Esteban J
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Summary Statement

Description of an original in vitro protocol for assessing combined bacteria and cell competitive adherence on the surface of biomaterials of medical interest

Objectives

Biomaterial-related infections are a major clinical problem. The pathogenesis of this syndrome has been described as a competitive adherence between bacteria and human cells in the so-called “race for the surface” theory. The aim of this study is to develop an in vitro protocol method that can be used to investigate this competence and its implications in the development of materials aimed to be used in orthopedic surgery.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 37 - 37
1 Jul 2014
Molina-Manso D Del-Prado G Lucas-Diaz M Gómez-Barrena E Cordero-Ampuero J Esteban J
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Summary Statement

Combination of antibiotics with N-acetylcisteine and sub-MIC concentration of erythromycin was evaluated in two collection and 16 clinical strains of staphylococci isolated from PJI. The results were strain-dependent, so it evidences the necessity of perform individual studies of biofilm susceptibility.

Objectives

Staphylococci are the most common cause of prosthetic joint infections (PJI) (1), making the treatment of this disease difficult due to the increased resistance to antibiotics of biofilms. Combination between antibiotics and other compounds could be a good alternative. The aim of this study was to evaluate the effect of the combination of two compounds with nine antibiotics in biofilms formed by staphylococcal strains isolated from PJI.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 196 - 196
1 Jul 2014
Lozano D López-Herrradón A Portal-Núñez S Ardura J Vila M Sánchez-Salced S Mulero F Gómez-Barrena E Vallet-Regí M Esbrit P
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Summary Statement

Parathytorid hormone-related protein (107–111) loaded onto biopolymer-coated nanocrystalline hydroxyapatite (HAGlu) improves the bone repair in a cavitary defect in rat tibiae.

Introduction

Biopolymer-coated nanocrystalline hydroxyapatite (HAGlu) made as macroporous foams are promising candidates as scaffolds for bone tissue engineering applications. They exhibit optimal features, promoting internalization, proliferation and differentiation of osteoprogenitors, with an adequate cell colonization over the entire scaffold surface. Parathyroid hormone-related protein (PTHrP) is an important modulator of bone formation. Its 107–111 epitope (osteostatin) exhibits osteogenic properties at least in part by directly acting on osteoblasts. The main aim of this study was to evaluate whether osteostatin loading into HAGlu scaffolds might improve their bone regeneration capacity.


Bone & Joint Research
Vol. 3, Issue 3 | Pages 48 - 50
1 Mar 2014
Lidgren L Gomez-Barrena E N. Duda G Puhl W Carr A


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 144 - 144
1 Sep 2012
Perez-Jorge C Perez-Tanoira R Arenas M Matykina E Conde A Gomez-Barrena E
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INTRODUCTION

Biomaterial-related infections are an important complication in orthopaedic surgery [1], and Staphylococcus sp. accounts for more than half of the prosthetic joint infection cases [2]. Adhesion of bacteria to biomaterial surfaces is a key step in pathogenesis of such infections [3]. Titanium alloys are widely used in orthopaedic implants because their biocompatibility [4]. Surface incorporation of ions with antimicrobial properties, like fluorine, is one strategy previously studied with good results [5].

MATERIAL AND METHODS

A 18mm diameter rod of Ti–6Al–4V alloy ELI grade according to the standard ASTMF136-02 supplied by SURGIVAL was cut into 2 mm thick disk specimens, ground through successive grades of SiC paper to 1200 grade, degreased with a conventional detergent and rinsed in tap water followed by deionised water. The specimens were then chemically polished (CP).

The disks were anodized only on one side by using a two electrode cell in a suitable electrolyte. TiO2 barrier layers, without fluoride (BL), were produced by anodizing in 1 M H2SO4 at 15 mA cm-2 to 90 V, reaching 200 nm of thickness.

Fluoride barrier layers (FBL) were produced in an electrolyte containing 1 M NH4H2PO4 and 0.15 M NH4F, at constant voltage controlled at 20 V for 120 min at 20°C; the thickness of the layer is 140 nm.

Laboratory biofilm-forming strains of Staphylococcus aureus 15981 [6] and Staphylococcus epidermidis ATCC 35984 were used in adherence studies, which were performed using the protocol by Kinnari et al [7]. Photographs obtained were studied by ImageJ software. Statistical analysis was performed by EPI-INFO software. The experiments were performed in triplicates


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 112 - 112
1 Sep 2012
Molina-Manso D del Prado G Manrubia-Cobo M Ortiz-Pérez A Cordero-Ampuero J Gómez-Barrena E
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INTRODUCTION

Prosthetic joint related-infections (PJRI) are severe complications in orthopaedic surgery. Staphylococcus aureus and Staphylococcus epidermidis are the most commonly isolated pathogens from implants (1). The variable antimicrobial susceptibility found in these microorganisms, makes it necessary to perform individual susceptibility studies in order to select the best antibiotic combination for clinical management (2).

MATERIAL AND METHODS

35 staphylococcal strains (17 S. aureus, 18 S. epidermidis) were isolated from PJRI using a previously described sonication protocol (3). Biofilm-producing collection strains S. aureus 15981 (4) and S. epidermidis ATCC 35984 were also included in the study. In vitro susceptibility was evaluated against 7 antimicrobial agents: rifampin, vancomycin, ciprofloxacin, cotrimoxazole, cloxacillin, clindamycin, and daptomycin. Minimal Inhibitory Concentration (MIC) assays were determined according to EUCAST recommendations and breakpoints (5). Minimal Bactericidal Concentration (MBC) was also calculated by colony counting after plating the well contents.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_II | Pages 279 - 279
1 May 2010
Lòpez-Franco M Lòpez-Franco O Murciano-Antòn MA Gòmez-Barrena E Sánchez-Pernaute O Cañamero M Herrero-Beaumont G
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Aim: Osteoarthritis can be a progressive disabling disease, which results from the pathological imbalance of degradative and reparative processes. The synovium, bone, and cartilage are each well established sites involved in the pathophysiological mechanisms that lead to progressive joint degeneration. However, the role of meniscus is not known enough. We studied the distribution of cartilage oligomeric matrix protein (COMP) in man menisci and its changes in osteoarthritis

Patients and Methods: We studied 30 internal menisci from patients with knee osteoarthritis that underwent a total knee arthroplasty and meniscal tissue get from partial arthroscopic meniscectomy in 5 young patients that suffered internal meniscus tear within three months after the damage.

Meniscal samples were processed for histology, immunohistochemistry and in situ hybridization, for assessment of cell density, cells actively dividing as well as apoptotic cells, distribution of COMP and estimate the proteoglycan content.

Results: Osteoarthritic meniscus demonstrated areas depleted of cells and significant decrease in COMP immunostaining. Cell clusters were found around meniscal tears. We did not find cells activity dividing in the osteoarthritic group, but there were dividing cells in meniscectomy group. Proteoglycan staining was decreased in meniscus from osteoarthritis group.

Conclusions: Osteoarthritis leads to decrease cell population in menisci, loose of COMP as well as altered matrix organization. The role of meniscus in osteoarthritis of the knee is no clear but our results demonstrate changes in COMP and cells in osteoarthritis menisci. These changes reveal an altered scaffold and changes in the meniscus function. Perhaps these alterations have influence on development of knee osteoarthritis.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_III | Pages 455 - 455
1 Sep 2009
Esteban J Molina-Manso D Martín-de-Hijas N García-Almeida D Fernández-Roblas R Cordero J Gomez-Barrena E
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Biofilm development is a major factor in the pathogenesis of implant-related infections. However, there are only a low number of studies that analyses the ability of clinical isolates of bacteria to develop biofilm in vitro. Here we study biofilm development in several strains of Staphylococcus aureus and Coagulase-negative Staphylococcus (CNS) consecutively isolated from retrieved orthopaedic implants from patients diagnosed of implant-related infections.

We have evaluated in vitro biofilm development using the crystal violet technique in microtiter plates. Biofilm development was confirmed by visual microscopy and Confocal Laser Scanning Microscopy. Staphylococcal strains were isolated from implant-related infections by sonication of retrieved prosthesis as previously published by our group, and identified using conventional methods.

Twenty-seven strains (15 S. aureus, nine S. epidermidis, and one each of S. hominis, S. lugdunensis and S. warneri) were included in the study. Four strains of S. aureus (26.7 %) and one strain of S. epidermidis (8.3 %) did not develop biofilm in the test, showing OD lectures almost identical to the negative control. No statistical differences were detected between the two groups. The microscopic examination confirms this finding. Among the biofilm-producing strains, an important difference of the amount of biofilm produced was detected. One strain (S. aureus) produced biofilm in greater amount than all other strains, detectable even by visual examination of the plate.

In conclusion, not all staphylococcal strains isolated from implant-related infections are able to develop biofilm in vitro. There must be other pathogenic factors that are important in the pathogenesis of implant-related infections and need to be studied in order to develop a better strategy for treat these infections.