Are Tip-Apex Distance and Surgical Delay Associated with Increased Risk of Complications and Mortality Within the...

Background: Femoral neck fractures (FNF) have high mortality rates. Surgical delay likely contributes. Dynamic hip screw (DHS) fixation is common for FNF, and the tip-apex distance (TAD) measures screw position in the femoral head. A TAD >20-25 mm is considered a risk factor for screw cut-out. This study investigated the association between (1) surgical delay and complication/mortality rates within two years post-surgery and (2) TAD and postoperative complications following DHS in FNF. Methods: This retrospective study included 325 FNF patients who underwent DHS osteosynthesis at Regional Hospital Randers, Denmark from 2015-2021. The primary composite outcome included complications measured on radiographs (e.g., screw cut-out, avascular necrosis), reoperation, or death within 2 years. Radiographs were evaluated for TAD and postoperative complications/reoperations. Surgical delay was defined as the time from the diagnostic radiograph to the start of the operation. TAD was measured based on radiographs. Electronic patient journals and national SSN registers were used to assess reoperation and death rates. Results: The mortality rate was 16% within 1 year and 26% within 2 years. The complication rate was 16% within 2 years. The median surgical delay was 7.9 h (IQR 5; 14). Surgical delay was significantly associated with the 1-year mortality rate (p < 0.01), but not with the 1-year complication rate (p = 0.77). Surgical delay was associated with complication rates 2 years post-surgery only for undisplaced fractures, p = 0.046. The median TAD was 16.3 mm (13.8; 18.7); no association with complications <1 year (p = 0.56) or <2 years (p = 0.99) was observed. There were 59/325 patients with TAD >20 mm, six of whom had complications, and 6/59 with TAD >25 mm, none of whom had complications. Conclusions: We report a significant association between surgical delay and mortality rates in FNF, despite surgical delays <24 h. Additionally, there was a significant association between surgical delay and risk of complication/reoperation 2 years post-surgery for undisplaced fractures. No association was found between TAD and complication rates following DHS fixation for FNF; however, only a few TAD outliers were observed.