Study design
We retrospectively analysed young patients with FNFs in our hospital between January 2017 and January 2020 (all included patients were less than 60 years old). The demographic and radiological data of these patients were retrospectively collected from the institutional database. The study protocol was reviewed and approved by the institutional review board of the hospital. All patients provided informed consent for participation in the study.
Study population
All consecutive younger patients (age<60 years old) with FNFs who were primarily treated with FNS or CCS in our department from January 2017 to December 2019 and with a minimum of 6 months follow-up were included in the study.
Surgical technique
Spinal epidural anaesthesia or general anaesthesia was administered to the patient. All surgeries were performed by the same group of doctors. The patient was placed in the supine position on an orthopaedic traction table. After the C-arm X-ray machine confirmed that the fracture was in an adequate reduction position, conventional sterilization was performed.
FNS group: The affected limb was slightly abducted and internally rotated. A longitudinal incision of approximately 5cm was made under the greater trochanter. Subsequently, the lateral femoral surface was exposed for satisfactory hardware placement. First, we inserted an anti-rotation wire to fix the fracture. Then, we inserted a second guide wire as the central guide wire using a 130° angled guide. The proper position of the guide wire was confirmed by X-ray. We used a direct measuring device to determine the length and choose the proper implant. We then inserted the implant over the central guide wire into the pre-reamed hole. Next, we drilled a hole for the anti-rotation screw (ARscrew) and inserted it. Interfragmentary compression was applied by turning the insertion screw counterclockwise. The implant position was monitored during compression using X-ray. Finally, we attached a protection sleeve and drilled a hole for the locking screw and inserted it. (Surgical procedures in Figure 3).
CCS group: Three parallel guide pins were inserted into the femoral head along the longitudinal axis of the femoral neck in a triangular configuration. After the screws were in the correct position, three cannulated screws were screwed in and finally pressed evenly. Please note that the screw inlet should not be lower than the lesser trochanter to reduce the concentration of stress. The distal thread should pass through the fracture line completely. The top of the screw should be 5–10 mm below the femoral head cartilage, and the screw should be as close to the cortex as possible.
Perioperative Management
After ruling out blood disorders and or bleeding tendency preoperatively, low-molecular-weight heparin sodium (1 mg/kg body weight, once a day) was routinely used for anticoagulation. Antibiotics were administered 0.5 hours before the operation. After anaesthesia and resuscitation, the patient was be instructed to actively exercise isometric contraction of the lower extremity muscles, active ankle pump exercises, and active/assisted active hip and knee flexion exercises. Patients with osteoporosis were treated with calcium tablets and diphosphate. Partial weight-bearing training was performed according to the recovery of the affected limb. Approximately 3 months after the operation, walking with a load was permitted according to bone healing. X-ray examination was performed within three days after the operation. X-ray follow-up was performed once a month in the first six months after surgery and every six months thereafter. Hip function assessment was performed 6 and 12 months after the surgery. If the patient had hip pain on the surgical side during follow-up, computed tomography (CT) or magnetic resonance imaging (MRI) of the hip joint was performed to confirm the presence of fracture nonunion or femoral head necrosis.
Clinical outcome measure
The patients were retrospectively identified from the hospital database. Baseline and follow-up data were acquired from the electronic medical records. Patient records were reviewed and the following data were collected: height, weight, body mass index, time from injury to operation, operation time, blood loss, type of fracture internal fixation, types of fractures (Garden typing and Pauwels classification), and length of clinical follow-up. We used the Mercuriali et al. [5] method to calculate the volume of blood loss. All pre- and postoperative hip radiographs of the study cases were evaluated by the authors who reached a consensual decision for each case regarding the type of FNF (according to Garden and Pauwels classification).
The quality of postoperative fracture reduction was evaluated based on standard anteroposterior and lateral radiographs of the femoral neck of the affected side using the Garden alignment index [6]. Assessment of postoperative fracture healing: There was no obvious percussion pain in the hip joint or lower limbs on the operative side. X-ray or CT showed that the fracture line was blurred, and the original fracture end had continuous cancellous bone trabeculae passing through. Assessment for AVN of the femoral head mainly refers to the standard of Slobogean et al. [7]; that is, if the postoperative X-ray film showed partial collapse of the femoral head or subchondral translucent area. In addition, if the patient had local pain in the hip joint, AVN of the femoral head was suspected, and MRI of the hip joint was performed when indicated. The method of Zlowodzki et al. [8] was used to identify femoral neck shortening.
We used the Harris Hip Score to evaluate hip joint function preoperatively, and at 6 and 12 months after surgery. At the last follow-up, the Harris scoring system was used to score the function of the hip joint: a full score of 100 points, ≥90 points as excellent, 80-89 points as good, 70-79 points as medium, and <70 points as poor.
Statistical analysis
The statistical software used for all analyses was SPSS 25.0 (SPSS Inc., Chicago, IL, USA). Continuous variables were reported as mean ± standard deviation (with range). Discrete variables were reported as numbers ( percentage of total). Chi-squared tests or Fisher's exact probability method were used to compare binary variables (demographic data and complication rates).