Greater rate of cephalic screw mobilisation following proximal femoral nailing in hip fractures with a tip-apex distance (TAD) and a calcar referenced TAD greater than 25 mm

J Orthop Surg Res. 2018 May 2;13(1):106. doi: 10.1186/s13018-018-0814-1.


Background: To ascertain whether the tip-apex distance (TAD), calcar referenced TAD (CalTAD), and the sum of both (TADcalTAD) are predictive measurements of mobilisation of the cephalic screw in patients with trochanteric hip fractures.

Methods: Between 2014 and 2015, 68 patients (mean age 86 years, 45 females, 23 males) with a trochanteric hip fracture underwent intramedullary nailing. The TAD and CalTAD were measured, and for each parameter, we calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

Results: There is evidence of a statistically significant association between a TAD and CalTAD greater than 25 mm and a TADcalTAD greater than 50 mm and mobilisation of the cephalic screw. All measurements have similar sensitivity, but the TAD presents the highest specificity (p < 0.01).

Conclusion: To avoid the risk of mobilisation of the cephalic screw and possible subsequent failure of the construct, surgeons should strive for a TAD and CalTAD less than 25 mm and a TADcalTAD less than 50 mm when using intramedullary fixation.

Keywords: CalTAD; Fracture; Hip; TAD; TADcalTAD.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Bone Nails / standards*
  • Bone Screws / standards*
  • Female
  • Femur / diagnostic imaging*
  • Femur / surgery
  • Fracture Fixation, Intramedullary / instrumentation
  • Fracture Fixation, Intramedullary / methods
  • Fracture Fixation, Intramedullary / standards*
  • Hip Fractures / diagnostic imaging*
  • Hip Fractures / surgery
  • Humans
  • Male
  • Prosthesis Failure*
  • Reference Standards