Reverse obliquity femoral neck fracture: two cases report and review of the literature

Abstract Background:The literature defines a femoral neck fracture with a Pauwels angle of more than 70° as a vertical femoral neck fracture, which is one of the refractory fracture types. Clinically, there is a class of femoral neck fractures with a Pauwels angle ≥ 90° and a fracture line alignment that does not allow for Gotfried-positive support. we classified and named it as reverse obliquity femoral neck fracture（ROFNF）and report the treatment of two cases. Case presentation: The first case was a 56-year-old female admitted with a right femoral neck fracture (Pauwels III-type, Pauwels angle 95°) caused by a slip and fall while playing table tennis. The second case was a 45-year-old male admitted with a right femoral neck fracture (Pauwels III-type, Pauwels angle 90°) due to a rollover accident while driving an electric car. The patients were supine on a fluoroscopic operating table and offered lumbar epidural anesthesia. After failure of closed anatomical repositioning under fluoroscopy, both patients were treated with incisional repositioning via an anterior hip approach and internal fixation with three 7.3 mm cannulated screws in combination with a medial femoral neck buttressplate. The follow‑up radiographs at 9 months showed complete union of the bone fractures. Conclusions: This is the first reported of reverse obliquity femoral neck fracture with Pauwels angle≥ 90°. The course of treatment in our case showed that closed reduction and firm fixation of this rare type of femoral neck fracture were difficult, and open reduction via anterior hip approach and combined fixation were the optional treatment.