Intertrochanteric fracture is a common type of hip fracture in the elderly, accounting for about 36%. The majority of intertrochanteric fractures can be treated by closed reduction and internal fixation. PFNA and InterTan nail are the preferred intramedullary fixation systems for most intertrochanteric fractures [2, 3, 9]. Irreducible intertrochanteric fractures refer to fractures that cannot be effectively reduced by conventional closed traction. Radiographically, the proximal broken end is dislocated in the anterosuperior direction upon traction and the distal broken end in the posteroinferior direction. Besides, these fractures can hardly be corrected by increasing the traction weight. Type 31A1.3, 31A2 and 31A3 are irreducible intertrochanteric fractures [4–7, 10, 11]. In 2017, Chinese researchers  proposed the classification and treatment principles for irreducible intertrochanteric fractures. Type Ⅰ and Ⅱ fractures (irreducible either on the sagittal or coronary plane) are usually reducible with closed reduction and fixation using bucking bars and poking manipulation. They are mostly type 31A1.3 and type 31A2 fractures. However, type Ⅲ fractures (irreducible on both sagittal and coronary planes) are hardly reducible by closed reduction using bucking bars and poking manipulation. There have been no targeted therapies for this type of fractures so far. According to the existing research, the overall failure rate of surgery is higher for these fractures. Therefore, limited open reduction is recommended if closed reduction is ineffective for irreducible intertrochanteric fractures [5, 11–16], typically type 31A3 fractures as discussed in the present study.
The reasons for the difficult reduction in type 31A3 fractures can be summarized as follows: First, the fracture line runs in an opposite direction as the intertrochanteric line. The load transfer pattern along the fracture line results in the slip and instability of the distal fracture fragments. Second, the fracture line runs obliquely on the coronary plane from the posteroinferior to the anteromedial. Hence, the soft tissue hinge damage is serious in the front, and the femoral head floats. As a result, no immobilizing effect is exerted on the fracture fragments during closed reduction. Third, the proximal broken end is subjected to the action of short external rotator muscles, gluteus medius muscle, and gluteus minimus muscle and therefore is in abduction and dislocation. Furthermore, the proximal broken end is subjected to the joint action of the iliofemoral ligament and iliopsoas muscle and therefore is in an upward dislocation. The joint action of the two muscle groups results in the dislocation of the proximal broken end in a three-dimensional space, that is, forward, upward and outward simultaneously. However, the distal broken end is dislocated downwards due to the gravitational pull. Given the above three reasons, type 31A3 fractures are usually presented as dislocations on two planes, sagittal and coronary, in the elderly. Such fractures are hardly reducible under closed traction, so limited open reduction is needed.
However, during limited open reduction, the assistant may find it hard to maintain the reduction due to the more developed muscles in the proximal femur in type 31A3 fractures. In that case, the reduction should be assisted with Kirschner wires for temporary fixation or other instruments. When several Kirschner wires are used for temporary fixation, the contralateral cortex may displace due to the improper anterior or posterior position of the Kirschner wires, leading to the loss of reduction. If several Kirschner wires are inserted at different angles, they may mistakenly enter the medullary cavity, which affects the subsequent placement of intramedullary screws. Besides, the Kirschner wires generally have low holding power. The broken end is likely to dislocate as the intramedullary screws are inserted subsequently, leading to the loss of reduction. Some researchers tried to use titanium cables alone to assist reduction and fixation. However, there was still an average dislocation of 3 mm in the broken end postoperatively . This is because the proximal femur has a conical structure tapering downwards. The use of titanium cables alone for circumferential wiring can hardly give robust support. Moreover, the broken end may undergo micromovement during the nailing process, leading to downward slippage of the titanium cable and another loss of reduction.
For the reasons above, surgical procedures that can achieve and maintain reduction without causing too much trauma are needed. We innovatively combined intracortical screw technology and limited open reduction for irreducible intertrochanteric fractures in the elderly. Since osteoporosis is a prevalent condition in elderly patients, greater importance should be attached to reduction. Forcible screw insertion with poor reduction will finally lead to a dramatic increase in the risk of internal fixation [4, 10, 14]. Therefore, the authors abandoned closed reduction and performed limited open reduction instead to expose the broken end directly. The high-quality precision reduction was then achieved using minimally invasive reduction instruments. Intracortical screw technology was employed for fixation and reduction maintenance only after precision reduction and temporary fixation with Kirschner wires. The screw channel was made where the cortex was intact, and it was ensured that the channel was entirely inside the cortex. The reduction was strictly maintained due to the holding power of the screws, and another loss of reduction was avoided by this method. If the fracture line is too long or if there is no suitable site for the insertion of multiple intracortical screws, the minimally invasive titanium cables can be used to assist fixation. In this way, the screws and the cables work synergistically to increase the holding power. With satisfactory reduction achieved, all reduction instruments and the Kirschner wires for temporary fixation are safely withdrawn. By doing so, improper anterior or posterior insertion of the Kirschner wires can be prevented, avoiding insufficient temporary fixation and loss of reduction during the subsequent screw placement. This method can also prevent the entry of the Kirschner wires into the medullary cavity, which will affect the subsequent intramedullary nail placement. As demonstrated by our study, limited open reduction allows for effective reduction and fixation and reduction maintenance. This method prevents flask-shaped soft tissue damage that may be otherwise caused by repeated ineffective closed reduction using bucking bars, forceps holder, and poking manipulation.
For patients of advanced age, operation time and intraoperative blood loss have a direct bearing on patients' survival. As compared with the existing research, our method did not prolong the operation time or increase intraoperative blood loss [17, 18]. This is because the fastly performed limited open reduction can reduce time consumption and potential soft tissue damage and bleeding that are usually associated with repeated attempts of closed reduction. Besides, intracortical screws can effectively maintain reduction and reduce bleeding at the broken end.
For patients of advanced age, the reduction effect directly influences survival and prognosis and the complications associated with internal fixation. In the present study, the reduction effect was assessed using Kim's indicators. The excellent and good rate was 100% among our cases. This result fully demonstrated the safety and reliability of intracortical screw technology combined with limited open reduction. All of the elderly patients achieved satisfactory reduction, with reduction loss less than 1 cortical thickness, which was far superior to the standard of less than 4 mm .
This technology has some defects. First of all, limited resection and exposure of proximal femur raise higher requirements on surgical instruments and assistant's skills. Secondly, precision reduction and intracortical screw placement entirely within the cortex are to be done via a small incision. Therefore, the learning curve may be steeper and longer for some surgeons.
Our study had certain limitations, including a small sample size and short duration of follow-up. Our research findings remain to be verified through studies with a longer follow-up and a larger sample size.
To conclude, intracortical screw technology plus limited open reduction could achieve high-quality reduction and fixation in elderly patients with type 31A3 irreducible intertrochanteric fractures. A good clinical efficacy was attained without increasing operation time and intraoperative blood loss.