PFNA internal fixation technique
PFNA internal fixation technique
PFNA (Proximal Femoral Nail Antirotation), the proximal femoral anti-rotation intramedullary nail. It is suitable for various types of femoral intertrochanteric fractures; subtrochanteric fractures; femoral neck base fractures; femoral neck fractures combined with femoral shaft fractures; femoral intertrochanteric fractures combined with femoral shaft fractures.
Main nail design features and advantages
（1）The main nail design has been demonstrated by more than 200,000 cases of PFNA, and it has achieved the best match with the anatomy of the medullary canal；
（2）6-degree abduction angle of the main nail for easy insertion from the apex of the greater trochanter；
（3）Hollow nail, easy to insert；
（4）The distal end of the main nail has a certain elasticity, which is easy to insert the main nail and avoids stress concentration.
Spiral blade:
(1) One internal fixation simultaneously completes anti-rotation and angular stabilization;
(2) The blade has a large surface area and a gradually increasing core diameter. By driving in and compressing the cancellous bone, the anchoring force of the helical blade can be improved, which is especially suitable for patients with loose fractures;
(3) The helical blade is tightly fitted with the bone, which enhances the stability and resists rotation. The fracture end has a strong ability to collapse and varus deformity after absorption.
The following points should be paid attention to in the treatment of femoral fractures with PFNA internal fixation:
(1) Most elderly patients suffer from basic medical diseases and have poor tolerance to surgery. Before surgery, the general condition of the patient should be comprehensively evaluated. If the patient can tolerate the surgery, the surgery should be performed as early as possible, and the affected limb should be exercised early after surgery. To prevent or reduce the occurrence of various complications;
(2) The width of the medullary cavity should be measured in advance before the operation. The diameter of the main intramedullary nail is 1-2 mm smaller than the actual medullary cavity, and it is not suitable for violent placement to avoid the occurrence of complications such as distal femur fracture;
(3) The patient is supine, the affected limb is straight, and the internal rotation is 15°, which is convenient for the insertion of the guide needle and the main nail. Sufficient traction and closed reduction of fractures under fluoroscopy are the keys to successful surgery;
(4) Improper operation of the entry point of the main screw guide needle may cause the PFNA main screw to be blocked in the medullary cavity or the position of the spiral blade is eccentric, which may cause the deviation of fracture reduction or the stress shearing of the femoral neck and femoral head by the spiral blade after surgery, reducing the the effect of surgery;
(5) The C-arm X-ray machine should always pay attention to the depth and eccentricity of the screw blade guide needle when screwing in, and the depth of the screw blade head should be 5-10 mm below the cartilage surface of the femoral head;
(6) For combined subtrochanteric fractures or long oblique fracture fragments, it is recommended to use an extended PFNA, and the need for open reduction depends on the reduction of the fracture and the stability after reduction. If necessary, a steel cable can be used to bind the fracture block, but it will affect fracture healing and should be avoided;
(7) For split fractures at the top of the greater trochanter, the operation should be as gentle as possible to avoid further separation of the fracture fragments.
Advantages and Limitations of PFNA
As a new type of intramedullary fixation device, PFNA can transfer load through extrusion, so that the inner and outer sides of the femur can bear uniform stress, thereby achieving the purpose of improving the stability and effectiveness of internal fixation of fractures. The fixed effect is good and so on.
The application of PFNA also has certain limitations, such as difficulty in placing the distal locking screw, increased risk of fracture around the locking screw, coxa varus deformity, and pain in the anterior thigh area caused by irritation of the iliotibial band. Osteoporosis, so intramedullary fixation often has the possibility of fixation failure and fracture nonunion.
Therefore, for elderly patients with unstable intertrochanteric fractures with severe osteoporosis, early weight bearing is absolutely not allowed after taking PFNA.