We retrospectively analyzed the medical records of patients with intertrochanteric hip fractures operated in two centers between January 2016 and July 2019. The trauma database of each institution was reviewed to identify patients, using the corresponding codes with intertrochanteric hip fracture and surgical treatment with a cephalomedullary nail as search criteria. Subsequently, the data was collated with the medical records of the institutions to obtain precision data. This study was conducted after obtaining the approval of the Ethics Committee of both institutions.
Patients aged > 65 years treated with short cephalomedullary nails were included. Exclusion criteria were previous surgery in the contralateral hip, pathological fractures, and lack of clinical/x-ray follow-up to assess fracture healing—whether due to death or loss to follow-up.
All patients were operated underwent minimally invasive surgery with intraoperative radioscopy on a traction table in a supine position. Closed reduction was attempted in all cases. The cephalomedullary nails utilized were made of steel, with an angle of 130°, a single cephalic lag screw to the head (no blade), and a single dynamic distal locking.
On the first postoperative day, all patients were allowed full-weight bearing with assistance, as tolerated, except no ambulatory patients.
Radiological examinations were performed before and after surgery, 6 weeks, and 3, 6, 9 and 12 months. X-ray examination included anteroposterior (AP) and lateral (L) views of the hips.
Age, gender, and side of fracture, were recorded. Preoperative AP and L X-ray views were reviewed to identify fracture stability according to AO/OTA classification (31.A1–31A2.1 were grouped as stable; and 31.A2.2 -A2.3 as unstable) [13].
Immediate postoperative X-rays were review to assess femoral neck angle (FNA), reduction quality, lag screw position on the femoral head, and tip to apex distance (TAD).
FNA was measured in the operated and contralateral hip in the AP and L views and differences were calculated. The reduction quality was categorized according to a modification of the method developed by Baumgaertner et al. based on two criterions asses on AP and L views [5]. FNA of 125–130º on AP and less than 20º of angulation on the L view was the first criterion. The second criteria were the presence of less than 4mm of displacement of any fragment in both views. If both criteria were met, the reduction was categorized as good, if only one or neither criteria were met the reduction was acceptable or poor, respectively.
For the lag screw position, the femoral head was divided into three regions on AP (inferior, center, superior) and L views (posterior, center, anterior) according to Cleveland´s method [14]. For this, the placement of the tip of the lag screw in the femoral head was considered.
TAD was calculated according de the method described by Baumgaertner et al., according to which, a distance of ≤25mm is adequate [5].
These measurements were performed by two independent authors and discrepancies were resolved by the senior author.
Non-union was defined as the absence of bone callus at nine months after surgery and lack of radiographic healing progress in the last 3 months. Complications related to loss of fixation of cephalic screws in the femoral head (i.e. cut-through and cut-out) were also analyzed. Cut-out was defined as the extrusion of the screw from the superior cortex of the femoral head or neck and cut-through as the axial migration of the screw with joint penetration. On basis of nonunion, cut-out, and cut-through occurrence the study population was divided into two group failure and non-failure groups.
Statistical Analysis
A Student’s t-test or Wilcoxon´s test was used to compare continuous variables between failure and nonfailure groups, and a Chi-square or Fischer’s test to analyze the relationship between categorical variables.
In order to analyze whether a variable exerted any influence on the incidence of complications, logistic regression analysis and selected the variables using a step-by-step method were applied. When assessed separately, due to the low frequency of each individual complication, Firth’s logistic regression was used. Uni and multivariate logistic regression analysis results were presented as odds ratio (OR) for statistically significant variables. For the purposes of drawing statistical conclusions, a p-value < 0.05 was considered statistically significant. Statistical analysis was conducted using R Software (Language and Environment for Statical Computing, R Foundation for Statical Computing, Vienna, Austria)