Proximal femoral fractures, including intertrochanteric and subtrochanteric fractures, are a frequent and common type of fracture, mostly seen in elderly people, while in young people they are caused by great violence, with many complications and serious injuries, thus posing a higher demand for the treatment of this type of fracture. From March 2004 to May 2005, we treated 35 cases of proximal femur fractures with AO dynamic condylar screw (DCS) internal fixation. The clinical results are summarized as follows.
1. Clinical data
Among the 35 cases, there were 23 males and 12 females, aged 21-88 years old, average 66 years old, 4 cases of car accident, 29 cases of self-inflicted fall injury, 2 cases of fall injury, 26 cases of left side and 9 cases of right side, all of them were closed fractures, 33 cases were seen after 2 hours to 7 days of injury, 1 case each was 21 days and 30 days. According to the classification of AO[1], there were 2 cases of A1.1 type, 5 cases of A3.1 type, 8 cases of A3.2 type, 10 cases of A3.3 type, 8 cases of subrotor fracture, and 2 cases of subrotor fracture combined with inter-rotor fracture. There were 6 cases of diabetes mellitus, 10 cases of hypertension, 18 cases of cardiac disorders, 3 cases of cerebral thrombosis, and 3 cases of fractures in other parts.
2. Treatment methods
2.1 Preoperative treatment of closed proximal femur fracture without other combined injuries should be routinely given immediate skin traction, and for severe displacement deformity, bone traction should be performed, which not only relieves the pain at the initial stage of trauma, but also facilitates the reset of the fracture. At the same time, actively improve the preoperative auxiliary examinations and treat the comorbidities in time. After the condition is stabilized, elective surgery should be performed.
2.2 The patient was placed in the supine position under continuous epidural anesthesia, and the operating area was routinely disinfected and toweled with the affected hip padded at 30°. The fracture is repositioned under fluoroscopy with a G-arm x-ray machine, and the indirect repositioning technique should be used as much as possible to reduce the destruction of the blood supply at the fracture end and facilitate the healing of the fracture. After the fracture is satisfactorily repositioned under fluoroscopy, a guide pin is inserted at 1.0 cm above the greater trochanter using a 95° guide, which should be parallel to the axis of the femoral neck and located in the lower 1/3 of the femoral head under orthogonal fluoroscopy. and reaming along the guide pin, tapping and then screwing in the appropriate length of condylar screw. A suitable sleeve plate is installed and the plate and femoral stem are firmly fixed with matching screws, and finally the fracture end is given moderate pressure by screwing in the compression screws. If there is a combined fracture of the lesser trochanter and the fracture mass is large, tension screw fixation should be given to restore the integrity of the medial bone cortex. Flush the operative area, place a negative pressure drainage tube, and close the incision layer by layer.
2.3 Postoperative treatment After the operation, give routine care after continuous epidural anesthesia, clear heat and cool blood, activate blood circulation and resolve blood stasis, and promote water retention and swelling by oral administration of traditional Chinese medicine with angelica, sequestra, wei ling xian, safflower, honeysuckle, wild chrysanthemum, dandelion, bupleurum, scutellaria, red peony and qiang wu, together with antibiotic drugs to prevent infection. The patient should be kept in a supine position with the affected limb in an abducted neutral position and wear anti-rotation shoes. Immediately after surgery, patients should be instructed to perform functional exercises of the quadriceps and ankle joints of the affected limbs to prevent the occurrence of venous thrombosis in the lower limbs. The incision was routinely changed surgically 24 to 48 hours after surgery, and the negative pressure drainage tube was removed. CPM machine exercise was given to the affected limb. According to the patient’s bone quality and the degree of intraoperative fixation, generally after 2-4 weeks, the patient could get out of bed to support the double crutches for partial weight-bearing activities of the affected limb, without cross-leggedness or lateral lying.
3.Treatment results
The postoperative radiographs of 35 cases in this group showed that the fracture was anatomically repositioned in 28 cases, nearly anatomically repositioned in 5 cases, and functionally repositioned in 2 cases, and the power condylar screws were firmly fixed. 34 cases had stage I healing of the surgical incision, and 1 case had delayed healing of the incision. In this group, 33 cases were followed up after surgery, the shortest follow-up period was 4 months, the longest was 10 months, and the average was 6 months. X-ray films were taken to show that all of them reached bony healing, and the average healing time was 5 months (3 months to 6 months). There was no 1 death, and 2 cases developed first-degree decubitus ulcers (which were cured after symptomatic treatment). The efficacy was evaluated according to the Harris hip function standard [3]: 22 cases were excellent and 9 cases were good, with an excellent rate of 93.9%.
4. Discussion
4.1 The choice of treatment method proximal femur fracture is mostly found in the elderly, and the average age of onset is 8 years higher than that of femoral neck fracture. Patients in this age group are more or less combined with medical disorders, such as heart disease, diabetes mellitus, hypertension, cardiovascular and cerebrovascular pathologies, and their quality of life is not high. Patients with proximal femur fractures have a high mortality rate.
A statistical comparison of the mortality rates of patients in the conservative and surgical treatment groups showed that the mortality rate in the conservative treatment group was 41%, while the mortality rate in the surgical treatment group was 13%. The four young patients in this group were all caused by car accidents and had other injuries, and the fractures were mostly comminuted and had poor stability, so strong internal fixation and early functional exercise of the affected limbs were more beneficial to the patients’ recovery and reduced the pressure of care. From the anatomical relationship of the proximal femur, the local distribution of reasonable and complex trabeculae is an important part for carrying human activities, and poor alignment will cause non-union of the fracture or hip inversion or valgus, resulting in disability of the limb.
4.2 Biomechanical principle of power condylar screw is composed of power compression screw, 95° sleeve condylar plate, caudal compression nail and matching cortical bone screw. The power compression screw is semi-threaded and has a tendency to slide between the 95° sleeve condylar plate and the 95° sleeve condylar plate when the force is applied, which facilitates fracture healing and makes the fracture end more stable. The sleeve condylar plate is placed on the lateral cortex of the femoral rotor, which effectively carries the tension load and has the role of a tension band, making the fracture end more stable and allowing the patient to perform functional exercises of the limb at an early stage.
4.3 Perioperative experience
Pre-operative treatment of comorbidities should be actively carried out, because most of the patients are elderly and often have combined medical disorders. Pre-operative targeted treatment can minimize the probability of accidents during surgery and create good prerequisites for smooth operation, which is also the key to successful surgery.
During surgery, after the lateral femoral muscle is exposed, the posterior edge of the lateral femoral muscle should be stripped subperiosteal and pulled forward to reveal the proximal femur and greater trochanter. The separation of the lateral femoral muscle fibers should be avoided as much as possible, causing excessive bleeding in the operative area.
③The fracture end should be repositioned as indirectly as possible to reduce local soft tissue stripping to facilitate fracture healing.
④The depth of condylar screw entry into the femoral head should reach 0.5 cm to 1.0 cm below the articular cartilage surface and through the intersection of tension and pressure resistant trabeculae in order to control the proximal end of the fracture more effectively. It should also be noted that the condylar screw should be positioned as high as possible at the proximal end of the fracture so that more screw fixation can be obtained at the proximal fracture end to make the internal fixation more solid.
⑤ While the mechanical strength and design rationality of the internal fixation is important, it should not rely solely on the strength of the internal fixation, but should achieve stable fracture repositioning, which is necessary to maintain the effect of internal fixation.
Particular attention should be paid to the restoration of the integrity of the medial cortex of the fracture to reduce the chance of hip inversion at a later stage, and this is mostly reflected in the repositioning of the femoral trochanter, which can be fixed with one to two tension screws after the repositioning of the femoral trochanter, and if necessary, bone grafting is feasible to restore the integrity of the medial cortex. If it is difficult to achieve anatomical repositioning of the fracture during surgery, the distal fracture can be displaced inward and the force arm can be shortened by relying on the femoral spine support to enhance the stability of the fracture and the effect of internal fixation.
(6) Early postoperative functional exercise is necessary for limb recovery. Patients can be instructed to perform contraction exercises of the quadriceps muscle, and if the internal fixation is secure, exercise of the lower limb CPM machine is feasible to prevent disuse atrophy of the affected limb muscles and prevent adhesions of the knee joint from long-term braking. However, inward contraction exercises of the affected limb and the patient’s habitual lateral recumbency should be avoided.
The selection of internal fixation should have the same bending strength and torsional stiffness as bone according to the biomechanical requirements, and the morphological design should meet the local biomechanical requirements.
DCS can effectively fix the proximal femur fracture and play a good role in power compression. DCS also has the advantages of high fixation strength, high weight-bearing capacity, low surgical trauma and low bleeding, and is therefore becoming more and more popular among clinicians and patients.
However, DCS for proximal femur fractures is not a panacea, and its clinical application should be mastered with strict indications. Generally speaking, according to the classification of AO, most A3 fractures are suitable for power condylar screw fixation, and the pressurization of the plate part as well as the antitension effect make the fixation of the fracture more stable. Among the 35 cases in our group, there were 23 cases of A3 type.
Some of the subtrochanteric fractures are also indications for power condylar screw fixation. 8 of the 35 cases in this group were subtrochanteric fractures, all of which had good fixation and solved the problem that the internal fixation of early subtrochanteric fractures was not strong enough. For the complex fractures of the proximal femur, the power condylar screw showed its superior fixation. In this group, there were 2 cases of subtrochanteric fractures combined with intertrochanteric fractures, and only the power condylar screw alone was used to obtain reliable fixation without the need for other auxiliary internal fixation materials, with reliable efficacy.
Most of the type A1 fractures can be fixed with power hip screws, but the two cases of type A1.1 in this group had incomplete bone cortex at the entry point of hip screws, while the entry point of condylar screws had good bone cortex in the greater trochanteric area of the femur, so we applied power condylar screws and also obtained good results.