Aramid-epoxy composite internal fixation plates: a pilot study.

Mechanical tests were conducted on an aramid-epoxy composite laminate in vitro and in vivo to determine its suitability for internal fixation plates. This material, fashioned into blank test coupons the size of the standard 4-hole AO-ASIF plates, had a tensile modulus of elasticity significantly lower than bone. In three-point bending, blank test coupons exhibited a low yield strength that would limit utility in significant load-bearing situations, but changes in the layer configuration of the composite could be expected to improve this characteristic.

Nonunions of fractures of the proximal and distal thirds of the shaft of the femur.

Subtrochanteric and supracondylar fractures of the femur are challenging, and specific anatomic and mechanical problems make fixation precarious. With careful selection of devices and techniques, nonunions may be avoided. Nonunion treatment requires strong immobilization and osteogenesis stimulation with bone grafts.

Experimental Nd:YAG laser disintegration of methylmethacrylate. Analysis of gaseous products.

The difficulty of removing intramedullary methylmethacrylate (MM) in revision of hip prostheses is considerable. To facilitate its removal from bone, Nd:YAG laser energy was delivered to a bovine anatomic specimen of the femur with the medullary canal filled with MM. Through an endoscope the laser was observed to soften and ablate the methyl methacrylate.

Zickel supracondylar nails for fractures of the distal end of the femur.

Between 1974 and 1984 the Zickel supracondylar nail system was used to fix 82 femora. Sixty-nine femora had supracondylar fractures and 13 supracondylar osteotomies. A high rate of union (98%) was achieved in the fracture group, which included a variety of fracture types, but five supracondylar osteotomies failed to unite initially and required additional surgery.

Knee joint angle: its relationship to quadriceps femoris activity in normal and postarthrotomy limbs.

The relationship of knee joint angle to maximum effort quadriceps femoris activity, as measured by smoothed and rectified EMG, was systematically examined in 30 normal and 18 post-meniscectomy limbs. Our results show that motor unit activity depends not only upon joint angle, but also upon peripheral receptor feedback, which is altered in the post-arthrotomy limbs, producing the characteristic "extensor lag" or inability to maintain the knee at 0 degrees while flexing the hip. The significant interaction of joint position and limb condition must therefore be taken into account when evaluating or rehabilitating pathologic joint conditions.

Subtrochanteric femoral fractures.

Femoral fractures in the subtrochanteric and proximal shaft regions require special management because of the great stresses inflicted on the area. Stability is best achieved with intramedullary fixation when there is adequate control of both proximal and distal fragments. Intertrochanteric fractures with small subtrochanteric components can often be adequately fixed with strong nail plate or screw plate devices.

Fractures of the adult femur excluding the femoral head and neck: a review and evaluation of current therapy.

A review and appraisal of current methods of treatment of fractures of the femur including operative and nonoperative methods as well as complications or limitations of various methods, reveals that a specific appliance or procedure is of value only when used with proper indication and proper technique. When internal fixation is performed, load-sharing between appliance and bone is mandatory, because of the large mechanical stresses involved. Intramedullary fixation permits load-sharing more often than extramedullary fixation and should be used on femoral fractures whenever possible.

A new intramedullary fixation device for the distal third of the femur.

A new fixation device was designed for fractures of the distal third of the femur. An additional use has been for the stabilization of supracondylar osteotomies. The device consists of two- pre-shaped rods which are inserted through the medial and lateral femoral condyles into the medullary canal.

Intramedullary fixation of pathological fractures and lesions of the subtrochanteric region of the femur.

The Zickel intramedullary appliance was used without methylmethacrylate in forty-six patients to stabilize thirty-five fractures and eleven impending fractures associated with osseous lesions in the subtrochanteric region of the femur. Early mobilization or ambulation was possible in nearly all cases. The patients with actual fractures survived an average of 4.

An intramedullary fixation device for the proximal part of the femur. Nine years' experience.

Nine years' experience with a combined intramedullary rod and triflanged nail in eighty-four non-pathological fractures in the subtrochanteric region of the femur is reported and a system of classifying these fractures based on morphology is offered. The appliance was successful in permitting early mobilization of patients and afforded a high rate of union of the fractures. The problems of varus displacement of the distal fragment and protrusion of the device into the joint were not encountered, and there was only one mechanical failure.