Comment on: Should the tip-apex distance (TAD) rule be modified for the proximal femoral nail antirotation (PFNA)? A retrospective study
Ashwani Soni, SGGS Medical College and Hospital
2 December 2014
Dear Sir,
We read with interest the article “Should the tip-apex distance (TAD) rule be modified for the proximal femoral nail antirotation (PFNA)? A retrospective study” by Nikolosky et al. in journal of Orthopaedic Surgery and Research [1]. We would like to congratulate the authors for their informative work and would like to express our comments.
We fully agree with authors that less than 25mm tip apex distance concept of dyanamic hip screw (DHS) cannot be applied to proximal femoral nail (PFN) as such. DHS acts on the principle of sliding of lag screw into the barrel when there is collapse at fracture site. Free backward sliding of lag screw into the barrel decreases the stress at the lag screw-bone junction and prevents cut-out to some extent. Lacking of this phenomenon in proximal femoral nail (PFN) makes it an entirely different implant than DHS, biomechanically. Keeping this concept in mind large detailed study is required on in this area of concern.
References:
Nikoloski AN, Osbrough AL, Yates PJ. Should the tip-apex distance (TAD) rule be modified for the proximal femoral nail antirotation (PFNA)? A retrospective study.J Orthop Surg Res. 2013, 8(1):35. [Epub ahead of print]
Journal of Orthopaedic Surgery and Research
Comment on: Should the tip-apex distance (TAD) rule be modified for the proximal femoral nail antirotation (PFNA)? A retrospective study
2 December 2014
Dear Sir,
We read with interest the article “Should the tip-apex distance (TAD) rule be modified for the proximal femoral nail antirotation (PFNA)? A retrospective study” by Nikolosky et al. in journal of Orthopaedic Surgery and Research [1]. We would like to congratulate the authors for their informative work and would like to express our comments.
We fully agree with authors that less than 25mm tip apex distance concept of dyanamic hip screw (DHS) cannot be applied to proximal femoral nail (PFN) as such. DHS acts on the principle of sliding of lag screw into the barrel when there is collapse at fracture site. Free backward sliding of lag screw into the barrel decreases the stress at the lag screw-bone junction and prevents cut-out to some extent. Lacking of this phenomenon in proximal femoral nail (PFN) makes it an entirely different implant than DHS, biomechanically. Keeping this concept in mind large detailed study is required on in this area of concern.
References:
Competing interests
none