To analyze and use the parameters in post-operative unstable intertrochanteric fractures treated using dynamic hip screw fixation as guidelines for re-operation
Keywords:Unstable intertrochanteric fractures, Dynamic hip screw, Tip apex distance, Lateral femoral wall integrity
Background: The treatment of unstable intertrochanteric fractures is challenging due to the difficulty in obtaining anatomical reduction. The purpose of this study was to analyse and use the parameters (lateral femoral wall integrity and tip-apex distance) in post-operative unstable intertrochanteric fractures treated using dynamic hip screw (DHS) fixation as guidelines for re-operation.
Methods: This was a prospective study and included 40 patients with unstable intertrochanteric fractures treated using DHS fixation from December 2014 to September 2016. The AO/OTA classification was used to classify each of the patients and their lateral femoral wall integrity and tip-apex distance was assessed in the post-operative radiographs.
Results: In this study, 3 patients out of 40 (7.5%) had screw pull out within 5 months of surgery. 2 pull outs occurred when the screw was in the antero-superior zone and 1 when it was in the centre to centre zone. Thus, the rate of screw pull out was higher in the antero-superior zone. The 3 patients with screw pull out had a mean tip-apex distance (TAD) of 36.01 mm as compared to 32.96 mm of those who did not have screw pull out. We further found that pre-operatively 6 patients out of 40 (15%) had lost lateral femoral wall integrity whereas post-operatively 26 patients out of 40 (65%) had lost it. In summary, there is a 5 times higher risk of losing lateral femoral wall integrity if DHS is the implant of choice.
Conclusions: On conclusion, unacceptable TAD limit with loss of lateral femoral wall integrity was found to be a definite indicator of DHS implant pull out. And also found that by using the DHS as an implant of choice, there is a 5 times higher risk of losing lateral femoral wall integrity intra-operatively and that its use for the treatment of unstable intertrochanteric fractures must be guarded.
Bannister GC, Gibson AG, Ackroyd CE, Newman JH. The fixation and prognosis of trochanteric fractures. A randomized prospective controlled trial. Clin Orthop. 1990;254;242-6.
Bridle SH, Patel AD, Bircher M, Calvert PT. Fixation of intertrochanteric fractures of femur. A randomized prospective comparison of the Gamma nail and dynamic hip screw. JBJS. 1991,73(2):330-4.
Clawson DK. Trochanteric fractures treated by sliding screw plate fixation method. J Trauma. 1964;4:737-52.
Kaufer H. Mechanics of treatment of hip injuries. Clin Orthop. 1980;146:53-61.
Davis TRC, Sher JL, Horsman A, Simpson M, Porter BB, Checketts RG. Intertrochanteric femoral fractures. Mechanical failure after internal fixation. JBJS. 1989;72(1):26-31.
Doherty JH, Lyden JP. Intertrochanteric fractures of hip treated with the hip compression screw. Analysis of problems. Clin Orthop. 1979;141:184-7.
Lee YS, Huang HL, Lo TY, Huang CR. Dynamic hip screw in the treatment of intertrochanteric fractures: a comparison of two fixation methods. Int Orthop. 2007;31(5):683–8.
Gupta RK, Sangwan K, Kamboj P, Punia SS, Walecha P. Unstable trochanteric fractures: the role of lateral wall reconstruction. Int Orthop. 2010;34(1):125–9.
Geller JA, Saifi C, Morrison TA, Macaulay W. Tip-apex distance of intramedullary devices as a predictor of cut-out failure in the treatment of peritrochanteric elderly hip fractures. Int Orthop. 2010;34(5):719–22.
Haruna I, Kareem A. A review of tip apex distance in dynamic hip screw fixation of osteoporotic hip fractures. Niger Med J. 2012;53(4):184–91.