Design And Experimental Applications Of The Femoral Head With Off-center Drill Bulb-shaped Decompression Operation Equipement

Objective: Avascular necrosis of the femoral head(ANFH)of the localblood circulation disorder leading to bone cells, bone marrow hematopoieticcells,and fat cell death is caused by a variety of reasons, causing the fracture oftrabecular bone, a pathological change of femoral head collapse. the femoralhead core decompression therapy is exact widely used in early avascularnecrosis of the femoral head, in clinical. But, clinically, a kind of completedecompression, simple operation, is absenced. Through the femoral headoff-center drill bulb-shaped decompression surgical instruments andexperimental applications, in a bulb-shaped cavity within the femoral head, youcan completely clear the equipment necrosis of bone tissue femoral neckmarrow core decompression and bone graft new ideas.. Early detection andtreatment to prevent the collapse of the femoral head, bone support in the bonecavity and metal supports, the use of the support frame to the femoral headsubchondral bone plate to provide mechanical support to restore and maintainthe femoral head shape.Methods: Fresh7-8month castrated male healthy pigs slaughtered, dualfemur of a total of20specimens, to prepare for the experiment application, theapplication of off-center drill bulb-shaped decompression surgical instruments,(off-center core decompression drill, drill fixed sets of fixed sets of openingswith a hollow cavity and the ends were equipped with its conduction), the pigfemur head specimens using a vise fixed at the experimental stage, the greatertrochanter of femor25mm opening, with DHS hole drilling, trochanter distalcortical bone, drilling diagonally along the direction of the guide pin throughthe femoral neck up to the top of the drilling of femoral head subchondral boneof about5mm, the formation of bone femoral neck channel of about12mm. Femoral head off-center cutting drill bushing inserted through the femoral neckchannel to the femoral head area, a fixed shaft, turn the eccentric head rotationshaft when the cutter head resistance decreases, the end of a fixed power drill,complete the cutting, when shaft to rotate at the eccentric drill5mm at thefemoral head cartilage surface also rotate at the completion of the maximumdiameter of the cutting, no damage to the femoral head cartilage. Applicationeccentric drill12mm in diameter in the femoral head formed with a diameter ofabout16mm oval the fornix-shaped bone cavity which completely scrapecystic necrotic bone tissue of the femoral head, to form a bulb-shaped cavity.Results: Through the femoral neck, the femoral head cutting pigs20femoral specimens, an average of every pig femoral head specimens take about15minutes and26seconds with surgery.18of20porcine femur specimenssurgery went well and the results ware satisfactory, cutting range up to thefemoral head articular cartilage surface under5mm postoperative x-ray filmobservation that: the femoral head were seen in low density area, obviouslycavity, the shape of the bulb-shaped, with an average diameter of about15.9mmof the surgical instruments through the femoral neck pathway of the femoralhead, the surgical steps to simplify, shorten the time of minimally invasivesurgery, bone graft increase surgical trauma decreases.Conclusions: The femoral head necrosis was more common in youngpatients, if not for early treatment, more than85%of patients with clinicalsymptoms of Ficat Ⅰ and Ⅱ, within two years because of the collapse of thearticular surface of the femoral head replacement. Core decompression forpatients in early was better applicable in Ficat Ⅰ,and Ⅱ A avascular necrosisof femoral head in patients. Through the narrow straight about12mm of thediameter,through the femoral neck channel in zones of femoral head necrosisand excavation of the bone cavity of a maximum diameter of about16.1mm, soa more thorough removal of necrotic bone. To take minimally invasive bone,directional bone graft, femoral head core decompression drill before specificbending and oblique openings both significantly increased the cutting radius,cutting the femoral head necrosis of bone tissue, but not so hard to turn, and uniform grafting. grafting the area of dead space; but also according toindividual characteristics of the bone defect area, targeted bone graft boneparticles to ensure that plant to the exact location within the femoral head, inorder to achieve the precise grafting of the target area. Femoral head eccentricdrill bulb-shaped decompression surgical instruments to streamline, easy tooperate, convenient and safe, can achieve a further bone graft necrosis femoralneck femoral head core decompression and cutting bone tissue. This method isless damage is an effective method for the treatment of avascular necrosis.