Is calcar referenced tip-apex distance a better predicting factor for cutting out in biaxial cephalomedullary nails than tip-apex distance?

Abstract

Purpose: To test the significance of calcar referenced tip-apex distance (CalTAD) and the length of anti-rotation screw (AR screw) as predictors for failure after biaxial cephalomedullary (CM) nailing of intertrochanteric fractures. Methods: We retrospectively reviewed 190 consecutive fractures that had undergone biaxial CM nailing. Of these, 67 met the inclusion criteria of a non-pathological fracture with a minimum of 90 days radiological follow-up (mean 458 days; 91 days to 4.9 years). Results: The overall failure rate was 15% (10 of 67). Failure was associated with a higher CalTAD in most of the patients (13%, p < 0.001). A higher tip-apex distance (TAD) was not significantly associated with failure (p ¼ 0.132), when the CalTAD was less than 25 mm. When the AR screw length exceeded a line connecting the tip of the nail and the lag screw, screw cutout occurred only in one patient (p ¼ 0.095). Conclusion: Our data provide the first reported clinical evidence that the CalTAD is a better predictor of cutout in biaxial CM nailing than TAD measurement. However, the length of anti-rotational element does not seem to be an independent predictor of CM nailing failure.

Modified Short Proximal Femoral Nail for Intertrochanteric Fractures of Femur in Indian Patients - our Experience

“…Mean TAD total was 22.8mm while TAD ap and TAD lateral was 11.8 and 11.0mm respectively ( Table IV ). TAD has been poorly studied in biaxial cephalomedullary implants (having two screws) such as ours and currently there is no proven or recommended TAD for such implants 15 , 16 . Most frequent position of lag screw was charted in inferior-central zone in 95 cases ( Fig.…”

“…Baumgartner’s original description of TAD pertains with sliding hip screw system with a large single cephalic screw. It has been extrapolated and used in cephalomedullary nails including dual screw systems such as ours 15 , 16 . TAD was measured for only the lag screw as hip pin gets obscured by the lag screw in lateral view.…”

The Effect of Valgus Reduction on the Position of the Blade of the Proximal Femoral Nail Antirotation in Intertrochanteric Hip Fractures

“…Jiamton et al18) reported that the risk of perforation of the femoral head was decreased when the tip of the blade was located in the inferior half of the femoral head. Kashigar et al,10) Caruso et al,15) and Puthezhath and Jayaprakash12) reported that the risk was decreased when the calTAD decreased. In addition, according to Stiehl et al,9) the inferior side of the femoral neck is a dense trabecular structure, which is more resistant to loading stress than other parts of the femoral neck.…”

“…Second, we did not investigate the clinical outcome. In previous papers, the impact of blade position on the clinical outcome was already addressed 10121518). Therefore, we focused on assessing the quality of reduction and the position of the blade radiologically in this study.…”

“…In this regard, attempts have been made to decrease the tip-apex distance (TAD), which emphasizes positioning as deeply as possible in the center of the femoral head. In recent years, the concept of calcar referenced tip-apex distance (calTAD) has emerged on the grounds that placing the blade in the inferior part of the femoral neck and head is more biomechanically and clinically advantageous 9101112). Therefore, non-varus reduction and the good position of the blade, the two important factors in intramedullary fixation, should always be kept in mind during the surgery.…”