Clinical Study On Internal Fixation Of Femoral Neck Fracture Guided By Modified Pauwels Classification Based On CT Data Analysis

Objective: This study proposes a new method of classifying femoral neck fractures,called the modified Pauwels classification based on CT data analysis.The study systematically evaluates the feasibility and clinical value of using this classification to guide internal fixation treatment of femoral neck fractures through clinical studies.Method: Seventy-six patients who received internal fixation treatment(49cases of simple hollow screw fixation and 27 cases of hollow screw+medial support plate fixation)for femoral neck fractures from September 2020 to March 2022 at our hospital were collected,including preoperative pelvic radiographs,positive and lateral radiographs of the affected hip and CT plain + 3D reconstruction data,and postoperative pelvic radiographs and positive and lateral radiographs of the affected hip at January,March,June,and December.First,two junior orthopedic residents used the modified Pauwels classification based on CT data and the traditional Pauwels classification to classify the neck of femur fracture according to the preoperative imaging data.One month later,the order was rearranged and the previous doctor classified the fractures again.Collect the results of two classifications and evaluate the reliability and repeatability of the two types using the weighted Cohen’s Kappa coefficient.Subsequently,the improved Pauwels classification based on CT data analysis was used to classify fractures in all 76 patients,and the perioperative conditions(surgical time,bleeding volume,hospitalization time),fracture reduction(postoperative Garden index),pain and function(postoperative VAS score,Harris score),and postoperative ischemic necrosis of the femoral head were systematically evaluated and statistically analyzed for the two internal fixation methods in each classification of patients.Results: The agreement between the modified Pauwels classification based on CT data analysis was 0.835 for the same observer twice and 0.810 between the two observers,while the agreement between the traditional Pauwels classification was0.531 for the same observer twice and 0.490 between the two observers.To predict recovery of hip function,the percentage of excellent Harris scores at 12 months postoperatively in patients with each type of modified Pauwels classification was 92.30%for type A,90.00% for type B,and 61.50% for type C(P < 0.05),and the incidence of femoral head necrosis at the last follow-up was 7.70% for type A,18.00% for type B,and 38.50% for type C(P < 0.05).When comparing the two types of internal fixation,the bleeding volume in the hollow screw + medial support plate internal fixation group(162.50± 25.00 ml)was higher than that in the simple hollow screw internal fixation group(26.67±10.00 ml),and the postoperative Harris score at 12 months was lower than that in the simple hollow screw internal fixation group [(92.25±1.50)<(95.44±2.13)].In patients with modified Pauwels classification type B,the VAS scores at 3 and6 months after surgery were lower in the hollow screw + medial support plate group[(1.80±0.5),(0.27±0.46)] than in the hollow screw-only group [(3.00±1.06),(1.34±0.91)],but the operative time and bleeding were higher than in the hollow screwonly group [(1.00±1.06)].In the internal fixation group [(1.80±0.56h)>(1.40±0.38h),(150.00±53.45ml)>(27.75±7.50ml)],the postoperative 12-month Harris score was lower(92.27±0.88)than that of the hollow screw-only group(94.20±2.59).In patients with modified Pauwels classification type C,the bleeding volume in the hollow screw + medial support plate internal fixation group(181.25±59.39 ml)was greater than that in the hollow screw-only internal fixation group(38.0±19.95 ml),but the postoperative Harris score at 12 months was much higher than that in the hollow screw-only internal fixation group [(92.25±0.71)>(83.20±8.56)].Conclusion: Compared with the traditional Pauwels classification,the modified Pauwels classification based on CT data analysis was more reproducible and consistent in classifying femoral neck fractures and predicted the functional recovery and incidence of ischemic necrosis of the femoral head.Meanwhile,in terms of internal fixation selection,patients with type A and type B preferred hollow screw fixation alone,while patients with type C preferred hollow screw + medial support plate fixation.