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Biomedical subjects

Didier Hannouche

Publications and source records attributed to Didier Hannouche.

14 recordsLinked to original sources
PubMed2006

Induction of a barrier membrane to facilitate reconstruction of massive segmental diaphyseal bone defects: an ovine model.

OBJECTIVES: To report an ovine model that can be used to evaluate the efficacy of bone substitutes for repair of segmental diaphyseal bone defects. STUDY DESIGN: Experimental study. ANIMALS: Eleven 2-year-old Pré-Alpes Sheep. METHODS: Mid-diaphyseal metatarsal bone defects (25 mm long) were stabilized by a dynamic compression plate over a polymethylmethacrylate (PMMA) cement spacer, and by external coaptation. The PMMA spacer was removed at 6 weeks by incising the encapsulating membrane. The defect remained unfilled (Group 1; n=5) or was filled with morselized autologous corticocancellous graft (Group 2; n=6), the membrane sutured closed, and external coaptation applied for 6 months, when healing was evaluated. RESULTS: Radiographic, computed tomographic, and histologic examinations at 6 months after the 2nd surgery revealed non-union in ungrafted defects whereas grafted defects showed bone healing. The induced membrane had blood vessels, CBFA1+ cells, and very few macrophages entrapped in a collagenous tissue positive for type I collagen. CONCLUSION: This ovine metatarsal defect model resulted in a critical-size defect (non-union) that healed when grafted. The PMMA-induced membrane constrained the graft, was well vascularized, and may have osteogenic properties. CLINICAL RELEVANCE: This model may be useful to evaluate new strategies in bone tissue engineering because the PMMA-induced membrane may help confine bone morphogenetic proteins, skeletal stem cells, or other agents to the defect cavity where they could be useful to enhance bone formation.

Animals↗
PubMed2005

Hydrogel optimization for cultured elastic chondrocytes seeded onto a polyglycolic acid scaffold.

The purpose of this study was to compare the effect of different hydrogels on the production of tissue-engineered cartilage based on polyglycolic acid (PGA). Chondrocytes were isolated from adult sheep auricles. Alginate, Type I collagen, methylcellulose, and pluronic F127 hydrogels were evaluated, as were controls prepared without hydrogels. Proliferated chondrocytes were mixed with each hydrogel at 20 x 10(6) cells/mL and seeded onto PGA (1 x 1 x 0.2 cm, n = 60). The constructs were cultured with serum-free medium containing 5 ng/mL TGF-beta(2) and 5 ng/mL des(1-3)IGF-I in rotational bioreactors for up to 6 weeks. The cellular morphology, histology, and biochemistry were analyzed. Type I collagen, methylcellulose, and pluronic F127 displayed improved cartilage matrix deposition in terms of histology and biochemistry compared to alginate. It was not concluded that the combined seeding of chondrocytes and hydrogels on a PGA scaffold had significantly better effects than cell seeding without hydrogels. However, the histology and other useful findings in this ECM analyses suggested that Type I collagen and MC hydrogels were the best candidates for cartilage regeneration, because of their stimulation for chondrocyte proliferation in a three-dimensional culture as well as cartilage regeneration.

Animals↗
PubMed2005

The arterial vascularization of the lateral tibial condyle: anatomy and surgical applications.

The contribution of the inferior lateral genicular artery (ILGA) and the anterior tibial recurrent artery (ATRA) in the arterial supply of the lateral tibial condyle (LTC) has not been comprehensively studied and remains controversial. Eleven knee joints were injected with colored latex and the arteries were dissected macroscopically. The ATRA yielded several osseous branches supplying the tibial metaphysis and the anterior part of the tibial epiphysis and several rami supplying the anterior tibial tuberosity and the lower part of the patellar tendon. The ILGA ran under the lateral collateral ligament and had a horizontal direction towards the retro-patellar fat pad. The ILGA yielded 4-6 branches ascending or descending perpendicularly to its main direction. Full anastomoses between branches derived from the ATRA and the ILGA were observed in front and behind the lateral intercondylar tubercle in all the specimens, but each vessel seemed to provide predominantly the blood supply to a specific area. The anterior part of the LTC drew its blood supply from the ATRA, the posterior part from the ILGA and the mid-portion from both arteries. The standard anterolateral approach to LTC fractures with sub-meniscal arthrotomy appears particularly harmful to epiphyseal vascularization since it interrupts many of the branches deriving from the ILGA and ATRA. The recent development of arthroscopy in the treatment of LTC fractures may be particularly advantageous as it spares the vascularization of the LTC.

Aged↗
PubMed2005

Ceramics in total hip replacement.

Alumina-on-alumina total hip arthroplasty has been used for 32 years in Europe. The theoretical advantages of this combination are represented by its remarkable sliding characteristics, its very low wear debris generation, and its improved fracture toughness. These advantages are achieved if the material is processed properly with high density, high purity and small grains. We summarize the results obtained with the alumina-on-alumina combination concerning in vitro and in vivo wear behavior with special emphasis on wear debris characterization and quantification and histologic tissue examinations. Alumina-on-alumina seems to be one of the best choices in young and active patients provided that sound socket fixation is maintained in the long term.

Aluminum Oxide↗
PubMed2005

Cartilage engineering from ovine umbilical cord blood mesenchymal progenitor cells.

We aimed to determine whether three-dimensional (3D) cartilage could be engineered from umbilical cord blood (CB) cells and compare it with both engineered fetal cartilage and native tissue. Ovine mesenchymal progenitor cells were isolated from CB samples (n=4) harvested at 80-120 days of gestation by low-density fractionation, expanded, and seeded onto polyglycolic acid scaffolds. Constructs (n=28) were maintained in a rotating bioreactor with serum-free medium supplemented with transforming growth factor-beta1 for 4-12 weeks. Similar constructs seeded with fetal chondrocytes (n=13) were cultured in parallel for 8 weeks. All specimens were analyzed and compared with native fetal cartilage samples (n=10). Statistical analysis was by analysis of variance and Student's t-test (p<.01). At 12 weeks, CB constructs exhibited chondrogenic differentiation by both standard and matrix-specific staining. In the CB constructs, there was a significant time-dependent increase in extracellular matrix levels of glycosaminoglycans (GAGs) and type-II collagen (C-II) but not of elastin (EL). Fetal chondrocyte and CB constructs had similar GAG and C-II contents, but CB constructs had less EL. Compared with both hyaline and elastic native fetal cartilage, C-II and EL levels were, respectively, similar and lower in the CB constructs, which had correspondingly lower and similar GAG levels than native hyaline and elastic fetal cartilage. We conclude that CB mesenchymal progenitor cells can be successfully used for the engineering of 3D cartilaginous tissue in vitro, displaying select histological and functional properties of both native and engineered fetal cartilage. Cartilage engineered from CB may prove useful for the treatment of select congenital anomalies.

Animals↗
PubMed2004

Surgical treatment of persistent dislocation or subluxation of the ulnohumeral joint after fracture-dislocation of the elbow.

PURPOSE: To review the results of surgical reconstruction of posttraumatic elbow instability in the setting of either intact or repaired olecranon process using a protocol incorporating hinged elbow fixation. METHODS: Thirteen consecutive patients with ulnohumeral instability after a fracture-dislocation of the elbow, adequate articular surfaces, and adequate, stable alignment of the olecranon were treated with temporary hinged external fixation, preservation, or reconstruction of both the coronoid process and radiocapitellar contact and with repair or reconstruction of the lateral collateral ligament complex. There were 9 men and 4 women with an average age of 45 years. Seven patients had a terrible triad pattern injury and 6 had a posterior Monteggia pattern injury. All 13 patients had fracture of the radial head and 10 patients had fracture of the coronoid process. RESULTS: At an average follow-up period of 57 months stability was restored in every patient. The average Disabilities of the Arm, Shoulder, and Hand questionnaire score was 15 and the average Mayo score was 84, with 6 excellent, 4 good, and 3 fair results. The average arc of ulnohumeral motion was 99 degrees. Six patients had radiographic signs of arthrosis including 5 of 6 patients with olecranon fracture-dislocations. CONCLUSIONS: A stable, functional elbow can be restored in most patients with persistent instability after fracture-dislocation of the elbow using a treatment protocol incorporating hinged external fixation.

Adult↗
PubMed2004

Use of the Cusum technique for evaluation of a CT-based navigation system for total knee replacement.

Most of the early failures of total knee replacements are related to technical flaws. Conventional ancillary devices achieve good alignment in the frontal plane in only an average of 75% of total knee replacements. Computer-assisted surgery may improve the technical quality of implantation surgery. The aim of our study was to evaluate the use of computer-assisted surgery using a quality control process. Seventy-eight total knee arthroplasties were done with a CT-based computer-assisted surgery system. The outcomes studied were alignment of the lower limb, implant positioning, and operative time. The target for alignment was 180 degrees +/- 3 degrees. Cusum analysis showed that the three outcomes were controlled during the study. The cusum test identified any existing outliers. Because few data were available at the beginning of this study regarding computer-assisted surgery for total knee replacement, a randomized study was not relevant. However, a control of the procedure was mandatory. The cusum technique allowed continuous evaluation of the performance of the new procedure, and is a useful tool in assessing new technology. The results of this study showed that it is possible to do a randomized study to determine if computer-assisted surgery can improve the technical result of total knee replacement.

Adult↗
PubMed2003

Fetal tracheal augmentation with cartilage engineered from bone marrow-derived mesenchymal progenitor cells.

BACKGROUND/PURPOSE: The authors have described previously the use of engineered fetal cartilage in a large animal model of fetal tracheal repair. This study was aimed at comparing cartilage engineered from bone marrow-derived stromal cells (BMSC) to native and engineered cartilage, in this model. METHODS: Ovine BMSC were expanded in vitro, seeded onto biodegradable scaffolds, and maintained in transforming growth factor beta 1 (TGF-beta1)-supplemented medium for 3 months (group I). Identical scaffolds were seeded with fetal chondrocytes (group II). All constructs were analyzed in vitro, implanted into fetal tracheas, and harvested after birth for further analysis. RESULTS: There were no differences in survival between the groups. All BMSC-based constructs exhibited chondrogenic differentiation. Matrix analyses in vitro showed that both groups had similar levels of glycosaminoglycans (GAG) and type II collagen (C-II), but lower levels of elastin when compared with native fetal cartilage. Yet, compared with group II, group I had higher levels of GAG, equal levels of C-II, and lower levels of elastin. However, remodeling resulted in no differences between the 2 groups in any of these variables in vivo. CONCLUSIONS: The bone marrow may be a useful cell source for cartilage engineering aimed at the surgical repair of severe congenital tracheal anomalies, such as tracheal atresia and agenesis, in utero.

Animals↗
PubMed2003

Fetal tissue engineering: chest wall reconstruction.

BACKGROUND/PURPOSE: This study was aimed at applying fetal tissue engineering to chest wall reconstruction. METHODS: Fetal lambs underwent harvest of elastic and hyaline cartilage specimens. Once expanded in vitro, fetal chondrocytes were seeded onto synthetic scaffolds, which then were placed in a bioreactor. After birth, fetal cartilage constructs (n = 10) were implanted in autologous fashion into the ribs of all lambs (n = 6) along with identical, but acellular scaffolds, as controls (n = 6). Engineered and acellular specimens were harvested for analysis at 4 to 12 weeks postimplantation. Standard histology and matrix-specific staining were performed both before implantation and after harvest on all constructs. RESULTS: Regardless of the source of chondrocytes, all fetal constructs resembled hyaline cartilage, both grossly and histologically, in vitro. In vivo, engineered implants retained hyaline characteristics for up to 10 weeks after implantation but remodeled into fibrocartilage by 12 weeks postoperatively. Mononuclear inflammatory infiltrates surrounding residual PGA/PLLA polymer fibers were noted in all specimens but most prominently in the acellular controls. CONCLUSIONS: Engineered fetal cartilage can provide structural replacement for at least up to 10 weeks after autologous, postnatal implantation in the chest wall. Fetal tissue engineering may prove useful for the treatment of severe congenital chest wall defects at birth.

Animals↗
PubMed2003

Formation of a mandibular condyle in vitro by tissue engineering.

PURPOSE: Mandibular reconstructive procedures often produce significant donor site morbidity. Recently, the use of minimally invasive techniques has been reported for mandibular reconstruction with decreased morbidity at the primary operative site. To date, these techniques have not addressed the graft donor site. We hypothesize that tissue-engineering techniques may be used to fabricate bone and thereby eliminate donor site morbidity. METHODS: Porcine mesenchymal stem cells (pMSCs) were isolated from the bone marrow of 3 Yucatan minipigs and grown in standard culture flasks. When they became near-confluent, cells were detached and replated with the addition of osteogenic supplements. A model of a porcine mandibular condyle was made and used to fabricate porous polymer scaffolds from biodegradable poly DL-lactic-co-glycolic acid (PLGA). Differentiated osteoblasts were transferred to the PLGA scaffold and cultured for 6 weeks in a rotational oxygen-permeable bioreactor system. The cultured constructs, consisting of scaffold and cells, were evaluated by gross, radiologic, and histologic examinations. RESULTS: The engineered constructs were white and hard and had a shape that closely resembled that of the model condyle. Plain radiographs demonstrated that the radiodensity of the construct was between that of the normal condyle and that of control scaffolds. Histologically, bone was observed on the entire surface of the PLGA scaffolds with an average thickness of 0.03 mm. Bone was not observed in the control scaffolds. CONCLUSION: In this pilot study, autologous tissue-engineered bone constructs were successfully made by combining biodegradable polymers and pMSCs.

Alkaline Phosphatase↗
PubMed2003

Fractures of ceramic bearings: history and present status.

During a period of 25 years (1977 to 2001), 13 fractures of an alumina component were recorded retrospectively. During the same period, approximately 5500 alumina components were implanted (3300 with all-alumina bearings and 1200 with alumina-on-polyethylene). These events occurred in seven women and six men, with a mean age of 59 years and a mean weight of 71 kg. There were eight fractures of the femoral head and five fractures of the socket component. Three fractures clearly were related to trauma (two fractures of the socket and one fracture of the head) and two were related to an abnormal design (one 22-mm head and one extra-long neck). Five fractures occurred without any rational explanation, but two fractures that occurred in the early phase could have been caused by a weaker alumina material. Finally three recent fractures of the liner were related to a change in the design of the material. This has been corrected and no additional fractures were observed. Although this dramatic event is of concern, it is infrequent and easy to solve by a limited revision procedure if done emergently. This rare complication should be balanced with the other complications of THR, including mechanical failures and osteolysis, often described with metal-on-polyethylene prostheses.

Adult↗
PubMed2003

Long-term results of alumina-on-alumina hip arthroplasty for osteonecrosis.

Alumina-on-alumina bearings in THR may, in theory, provide an effective answer to osteolysis in young patients with ON of the femoral head. The purpose of this retrospective study was to report the long-term results of a series of 52 consecutive alumina THAs (41 patients) done for ON. The mean age of the patients at surgery was 41 years (range, 22-79 years). Cemented femoral stems with a 32-mm alumina head were used. Plain alumina cups were used and were either cemented (39 hips) or press-fit (13 hips). No patients were lost to followup. Sixteen hips have been revised. Aseptic loosening of the socket was the main cause of failure. At an average 16-year followup (range, 11-23.65 years), 26 hips were rated excellent and one hip was rated good. No osteolysis was observed and wear was undetectable. If revision for aseptic loosening was the end point, the rate of survival was 88.5% at 10 years for the socket and 100% at 10 years for the stem. With the alumina-on-alumina hip replacement done for ON, absence of osteolysis can be expected for as many as 24 years after the operation. New methods of socket fixation now are being explored.

Adult↗
PubMed2002

Engineered fetal cartilage: structural and functional analysis in vitro.

BACKGROUND/PURPOSE: This study was aimed at characterizing the structure and function of engineered fetal cartilage in vitro. METHODS: Chondrocytes from ovine specimens of fetal elastic, fetal hyaline, and adult elastic cartilage were expanded in culture and their growth rates determined. Cells were seeded onto synthetic scaffolds, which were then maintained in a bioreactor. Matrix deposition was determined by specific staining and quantitative assays for glycosaminoglycans (GAG), type II collagen (CII), and elastin, as well as compared with native tissue. Statistical analysis was by analysis of variance (ANOVA) and Students' t test, with significance set at P less than.01. RESULTS: Fetal elastic chondrocytes grew significantly faster than all other cell types. All fetal constructs resembled hyaline cartilage, regardless of the cell source. There were significantly higher levels of GAG and CII in fetal versus adult constructs, but no significant difference between fetal constructs from different sources. Unlike their adult counterparts, fetal constructs had GAG and CII levels similar to native tissues. CONCLUSIONS: Fetal chondrocytes can be rapidly expanded in culture. Compared with adult constructs, matrix deposition is enhanced in engineered fetal cartilage, which closely resembles native tissue, regardless of the cell source. Engineered fetal cartilage may be a preferable option during surgical reconstruction of select congenital anomalies.

Analysis of Variance↗