With socioeconomic development, the aging population is becoming more and more serious, and the accompanying osteoporosis has led to an increasing incidence of intertrochanteric fractures, which account for about half of hip fractures, with unstable intertrochanteric fractures accounting for 35-40% of these fractures. The Lichtblau study concluded that unstable intertrochanteric fractures have a potential risk of bone comminution, and even with relatively appropriate internal fixation treatment, osseous nonunion may occur, making the treatment of unstable intertrochanteric fractures relatively challenging and uncertain. There are many treatment options for unstable intertrochanteric fractures, and the choice of fixation method is controversial. Conservative treatment has many complications, and since the rise of the AO/ASIF school in the 1960s, internal fixation has become the treatment of choice for intertrochanteric fractures. The goal of surgical treatment is to achieve good fracture repositioning and firm fixation to allow for early postoperative bed release and partial weight bearing, to reduce complications associated with prolonged bed rest and to restore function as soon as possible, and to reduce the mortality and disability rates. The surgical treatment of unstable intertrochanteric fractures includes the following categories.
1 Lateral nail plate type
1. 1 Power hip screw (DHS)
The DHS is an extramedullary fixation method, the first one is the pressurized sliding goose head nail (Richard nail), which was improved by the International Society of Internal Fixation (AO) and called DHS. The DHS has reasonable mechanical properties and is structurally sound, allowing for early release from bed after internal fixation of the fracture and reducing long-term bed-ridden complications. Bartonet al concluded from a clinical study that DHS fixation is similar to Gamma nailing for unstable intertrochanteric fractures, and the cost of DHS fixation is less. DHS fixation has a more realistic application. On the other hand, the fixation system is relatively unstable in the axial, lateral and rotational directions. In unstable intertrochanteric fractures, the medial femoral neck is defective and the compressive stresses are difficult to be transmitted through the femoral spine, which may lead to fatigue fracture, fracture non-union or inversion deformity. DHS internal fixation was previously the gold standard for clinical treatment of intertrochanteric fractures, but its complication rate was as high as 23%, and DHS alone is not recommended for unstable intertrochanteric fractures. lindskog et al found that the addition of a rotor stabilizing plate or axial compression screws or intramedullary nails to DHS improved surgical outcomes and reduced postoperative complications. lee et al concluded that the addition of polymethylmethacrylate ( PMMA) bone cement to DHS reduced the incidence of these complications. Clinical experience has demonstrated that DHS has good clinical efficacy in the treatment of stable intertrochanteric fractures, but the application to unstable intertrochanteric fractures has more complications and further improvement is needed.
1. 2 Percutaneous compression plate (PCCP)
PCCP is a minimally invasive fixation method, which is a new type of internal fixation nail plate system developed by Gotfried etal from the concept of minimally invasive surgery and based on the plate design and biomechanical research. It consists of one plate, three cortical screws of the femoral stem and two power screws of the femoral neck, which are implanted percutaneously through two small incisions of 2 cm in length and assembled in the patient. The two fixation angle nail holes for placement of the femoral neck screws provide a biomechanically advantageous 135° cervical stem angle, and the two thin parallel femoral neck screws of the same diameter effectively prevent rotation of the femoral head and prevent screw slippage. damage to the lateral cortex. Biomechanical studies have demonstrated that PCCP has significantly better resistance to axial stress and torsion than DHS, and Knobe et al, Panesar et al showed good fixation in unstable intertrochanteric fractures with reduced operative time, postoperative infection rate, intraoperative bleeding, reoperation rate, and screw cutting complications compared to DHS. There is a trend toward decreased complications and satisfactory postoperative functional recovery. In addition, the surgical trauma is minimal and the degree of secondary trauma to the patient is greatly reduced. For unstable intertrochanteric fractures, especially in elderly patients with osteoporosis, PCCP is an ideal, safe, and effective minimally invasive operating system for the treatment of intertrochanteric fractures and has broad application value.
2 Intramedullary nailing system
2. 1 Gamma nail
The Gamma nail is an intramedullary central fixation with short force arm, which can bear more compressive stress, and the bending force acting on the fracture is relatively small, and the stress masking is small, and its pressurized threaded nail can have the effect of static pressure on the fracture. It can prevent displacement of the fracture end and the rotation and sinking of the intramedullary nail, and play a firm fixation role, which is less likely to cause fracture collapse, help fracture healing, avoid the occurrence of hip internal and external rotation, and allow early functional exercise after surgery. In addition, the Gamma nail is a closed operation, which causes less damage to the blood circulation at the fracture site and is in line with the principle of minimal invasion. It is significantly better than the lateral nail plate system in terms of operative time, trauma size, postoperative efficacy and complications. However, the main nail of the Gamma nail is thicker, and the stress concentration in the distal femur is more significant, which makes it prone to rotor splitting fractures and secondary femoral stem fractures, as well as the more frequent X-ray exposure of the Gamma nail during surgery and the higher price, which may limit its wide application.
2. 2 Proximal femoral intramedullary nail (PFN)
In response to the design flaws of the Gamma nail, AO/ASIF developed the PFN in 1996, which inherited the advantages of the short force arm, low bending moment, and sliding compression of the Gamma nail, and made a series of improvements, with the following main advantages: ① Since the PFN is closer to the femoral spine, the bending moment at the nail-nail junction is smaller, and it can share the load of the medial femoral neck cortex more than the lateral cortex; ② The fracture can be fixed with a reconstructive nail after resetting. (3) The use of two proximal tension screws effectively prevents rotational displacement of the fracture end; (4) For femoral rotor fractures involving medial cortical comminution, PFN avoids the need for anatomical reconstruction and reduces the proximal intramedullary nail diameter compared with the Gamma nail. Anjum et al [17] concluded that PFN is a more reliable and effective method of internal fixation, with It is less invasive, has less intraoperative bleeding, is simple to perform, and has a low rate of postoperative complications. In terms of reducing screw slippage and avoiding rotation of the cervical stem angle, Min et al concluded that PFN is more effective than Gamma nail, and fully affirmed the practical value of PFN. However, most clinical studies have shown that PFN also has the risk of bone resorption at the fracture end, tension screw cutting out of the femoral head, calcification of the greater trochanter, and inversion deformity. Foreign scholars, after clinical practice, believe that the accurate and precise selection of the appropriate position of the intramedullary nail has a significant impact on the effect of internal fixation, and the corresponding postoperative complications are also reduced to a certain extent, which has certain guiding significance for PFN internal fixation surgery. Domestic scholars also believe that based on the above advantages of PFN internal fixation, it is more suitable for unstable intertrochanteric fractures, especially for elderly patients, which is more in line with their surgical requirements. In summary, PFN has practical clinical application for unstable intertrochanteric fractures, and improved designs for its complications are emerging.
2. 3 Proximal Femoral Anti-rotation Intramedullary Nail (PFN-A)
The PFN-A not only combines all the features of the PFN, but also overcomes many of the technical shortcomings of the PFN. The advantages are as follows: (1) the main nail has a 6° flare angle, which allows the entry point to be located at the tip of the greater trochanter rather than in the pyriform fossa, which is more in line with the anatomy of the femur; (2) the spiral blade removes less bone than the screw, which provides greater resistance to extraction and better resistance to rotation and collapse; the wide surface of the end compresses the bone as much as possible and provides good holding power; (3) the distance between the end of the main nail and the locking screw is improved, and the longest possible length of the PFN-A nail can be used as the main nail. Sahinet and Takigami et al. concluded that PFN-A for unstable intertrochanteric and subtrochanteric femoral fractures has the advantages of shorter operative time, less trauma, less bleeding, faster recovery, higher fracture healing rate, and higher complications. Lenich et al used PFN-A to treat 120 patients with internal fixation, and the complication rate was 7.5%, which was significantly lower than that of DHS and PFN.
The consistency of the results of the above-mentioned clinical studies demonstrates that PFN-A is an ideal procedure for the treatment of unstable intertrochanteric and subtrochanteric fractures.
2. 4 Minimally invasive short reconstructive nailing (TAN)
Based on the Gamma nail, Lu et al. tried to use TAN to treat 80 patients with intertrochanteric fractures, and showed good results in terms of postoperative pain, walking, function, motor muscle
The TAN is a modified version of the Gamma nail, which differs from the traditional Gamma nail in that there are two tension screws of the same diameter in the femoral neck to improve stability and increase the anti-rotation effect, and the application of minimally invasive techniques also makes the operation time shorter, less bleeding and less risky, which may have a more optimistic application prospect.
3 Artificial prosthesis replacement
After a retrospective study of 563 cases of intertrochanteric fractures, Rasi et al concluded that intramedullary fixation is the appropriate surgical procedure for patients aged 45 to 65 years who can tolerate surgery. However, with the development of modern society, the number of elderly patients with intertrochanteric fractures with osteoporosis is on the rise, and most of them are unstable fractures, thus the surgical treatment with internal fixation alone often does not provide definite results, and experimental studies have demonstrated that the holding force of screws is linearly related to bone mineral density; at the same time, the bearing support of bones in elderly patients is reduced, making clinical repositioning difficult and prone to local collapse, screw withdrawal, and head nail penetration during weight bearing. The failure rate of internal fixation is high, and the long operation time and relatively high bleeding volume of internal fixation surgery are unfavorable to the postoperative recovery; on the other hand, elderly patients with poor general health and medical comorbidities are not easy to tolerate the secondary trauma caused by surgery.
For elderly patients with unstable intertrochanteric fractures, an important indicator of surgery is whether the procedure has the advantages of less trauma, shorter hospital stay, lower complications, lower morbidity and mortality rate, early mobility and functional recovery. Some scholars believe that for patients with advanced inter-rotor fractures, poor stability, heavy osteoporosis, and old inter-rotor fractures, artificial hip replacement is the most direct, effective, and rapid treatment that reduces postoperative complications and provides good pain relief. Arthroplasty is also a better option for patients with failed internal fixation. According to the patient’s age and frequency of joint activity, the expected service life of the joint, etc., we can determine whether to choose hemi- or total hip replacement. If the patient has good bone quality, the expected service life of the joint after replacement is long, and the acetabulum is heavily damaged or has obvious degenerative changes, we should choose total replacement, otherwise we can choose hemi-arthroplasty. However, it is worth noting that intertrochanteric femoral fracture prosthesis replacement is not widely used in clinical practice, and there are still controversies about artificial femoral head replacement for the treatment of severe osteoporotic unstable intertrochanteric fractures in elderly patients and after the failure of internal fixation, and the long-term efficacy of this procedure and whether it can meet the long-term survival of patients after joint reconstruction still need to be supported by large-scale clinical trial data and further in-depth research.
On the other hand, the difficulty of surgical operation of one-stage hip arthroplasty, unfamiliarity of orthopedic surgeons with lengthened prosthesis, high treatment cost, more intraoperative blood loss and postoperative painful shortening of the affected limb have limited the clinical application of artificial prosthesis replacement. Therefore, strict preoperative risk assessment, targeted selection of surgical methods and systematic postoperative recovery guidance are necessary.
4 Conclusion
With the increasing incidence of intertrochanteric femoral fractures, the clinical discussion about their surgical fixation methods is constantly updated and is a current research hotspot. Each fixation material has its own advantages and disadvantages for clinical application and is suitable for different types of intertrochanteric fractures; nor is there any one fixation material that is a panacea for all types of fractures. Although there is a considerable amount of literature on different surgical methods both at home and abroad, there is still a lack of data support from large-scale randomized trials, and their treatment results are still not very satisfactory. Careful preoperative evaluation and analysis, rational selection of surgical methods and fixation materials, improvement of surgical treatment outcomes, and avoidance of postoperative complications are the keys to the treatment of unstable intertrochanteric femoral fractures.