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Biomedical subjects

R Beccari

Publications and source records attributed to R Beccari.

8 recordsLinked to original sources

Anatomical comparative study of two vascularized bone grafts for the wrist.

Atrophic scaphoid non-union and lunate necrosis can be treated with vascularized bone grafting; through a posterior approach as described by Zaidemberg, based on a supraretinacular artery, or through an anterior approach, based on the volar carpal artery, according to Kuhlmann's procedure. The aim of our study was to determine the area covered by each of these two grafts and their respective future applications. Fifteen hands from eight adult human cadavers, free of any scar, were dissected after injection of colored fluid latex, through dorso-radial approach for Zaidemberg's graft and through volar approach for Kuhlmann's. We observed the morphological parameters of the pedicles and the arc of rotation of each flap. The volar vascularized graft had a constant origin and it could be transferred to the scaphoid, the lunate and the scapholunate joint. The posterior graft of Zaidemberg was technically more difficult to harvest because of the anatomical variations. It made it possible to reach the scaphoid, the trapezium and the scaphotrapeziotrapezoid joint line. Both these two vascularized bone grafts represent interesting procedures for treatment of scaphoid non-union or lunate necrosis, or intracarpal bones arthrodesis. They bring various possibilities of bone covering, related to specific area of mobilization and are not opposite procedures, but have different targeted indications. One must better define the respective places of the vascularized bone grafts, compared with the traditional free (non-vascularized) graft.

Adult↗

[Surgical replacement of the thumb saddle joint with the GUEPAR prosthesis].

Primary arthritis of the thumb saddle joint is very common. Among the different treatment options, the implantation of a total joint arthroplasty is an alternative. The GUEPAR prosthesis, developed by a group of French surgeons, is mainly used in elderly patients and only in cases with preserved trapezial height. This study reports the mid-term results of the second generation of this implant. The clinical results show good pain relief and good mobility of the thumb. There were a few patients with radiological signs of implant loosening, but none of them had clinical problems. The advantage of a total replacement of the saddle joint, compared to the standard resection arthroplasty, is faster rehabilitation and preservation of the length of the thumb. The new generation of the GUEPAR prosthesis has a more anatomical metacarpal stem and a modularity which allows the fit of the implants according to the anatomical situation.

Aged↗

[Guepar anatomical trapeziometacarpal prosthesis].

INTRODUCTION: A choice of surgical techniques of treatment for trapeziometacarpal (TMC) Osteo-Arthritis (OA) have been described. Total arthroplasty is often used, especially in France. Many papers have been published, presenting various prostheses. In English literature, this device is not thoroughly used. MATERIALS AND METHODS: [corrected] Guepar total arthroplasty is a cemented ball-in-socket prosthesis in metal-polyethylene. It includes an anatomical stem available in 4 sizes. After failure of the conservative treatment, total arthroplasty must be reserved to elderly patients, painful, with OA Dell stage III or IV aligned or not. The trapezial height must be sufficient. The authors reports the preliminary results of 64 Guepar prostheses, anatomical new design, implanted since 1995. RESULTS: Results of 63 prostheses are presented. One removal had been necessary at 9 months for metacarpal loosening (failure). Mean follow-up was 29 months. Clinical results were judged excellent or good in all cases. Regarding the radiological results, no modifications has been observed in 56 cases. Six radiolucent lines without displacement of the implants has been noted, with no incidence on clinical results. In one case, a metacarpal stem penetrated into the medullary canal in the bone axis but without any clinical modifications. DISCUSSION AND CONCLUSION: Clinically, in addition to pain relief, trapeziometacarpal prosthesis allows to preserve the first column length and to obtain a better opposition of the thumb as well of a better thumb-digits pinch, compared after trapeziectomy. Radiologically, as for total hip arthroplasty, the exact adaptation of an anatomical stem (new design) to the canal has probably a better prognosis at long term follow-up.

Adult↗

[Biomechanical evaluation of osteosynthesis with cannulated screws for Ponteau-Colles fractures in a bird model].

INTRODUCTION: The use of cannulated screw without protrusive head in Colles fractures could avoid some of the drawbacks of conventional pinning. In order to compare the mechanical resistance of Kirshner wires versus cannulated screws we designed a animal model of Colles fractures and tested three types of osteosynthesis: A: K-wires, B: Herbert cannulated screw, C: specific cannulated screws. METHOD: After creating a 10 mm defect in three sets of 10 fresh turkey tibia, 3 types of osteosynthesis were done and tested in compression with an Adamel Lhomargy machine: set A: K-wire fixation, set B: Herbert screws fixation and set C: specifics screws fixation. RESULTS: The compression strength needed for failure of the fixations were: for the K-wires (set A): 52 N +/- 17; for the Herbert screws (set B): 93 N +/- 39; for the specifics screws (set C): 160 N +/- 48; (p < 0.0001). DISCUSSION: The use of an animal model makes the experimentation easier and the sampling more homogeneous. In this model, resistance to compression of the cannulated screw was better than K-wires and the specific cannulated screw better than Herbert screw. Therefore clinical trial of osteosynthesis with cannulated screw in Colles fracture could be considered.

Animals↗