Abstract
Background: Dynamic hip screw (DHS) is a standard device for intertrochanteric fractures (ITF). Implant failure in form of screw cut out leading to varus collapse of neck shaft angle is associated with various factors like bone quality, fracture pattern, fracture reduction, lateral femoral wall thickness (LFWT), screw position and tip-apex distance (TAD). But there has been no clear consensus to the relative importance of each factor. The purpose of our study is to assess individual factors for a favorable outcome in DHS fixation of ITF. Materials and methods: 121 hips sustaining ITF treated with DHS between June 2014 and July 2016 were reviewed in our prospective study with a mean period of 12 months. Factors under study were bone quality,fracture pattern, fracture reduction, LFWT, screw position and TAD, which were recorded and used for statistical analysis using SPSS. Chi-square test, Independent t-test and Paired t-test were used to evaluate the significance of the differences. Final analysis involved clinical and radiological assessment using Harris Hip Score (HHS) and radiographs respectively. Results and Analysis: The mean age of patient at the time of surgery was 65.27±3.21 years (range 24-85) with 80 males and 41 females. There was no statistical significant relation found between implant failure and osteoporosis even though cases of failure were found in weak osteoporotic bones. Implant failure in relation to unstable fracture pattern, non-anatomical fracture reduction, LFWT< 21.77 mm, screw placement in position apart from centre or centre-inferior and TAD greater than 25mm was found to be statistically significant (p<0.05).The final functional and radiological assessment revealed 68.85% and 86.88% of hips respectively in good to excellent category. Conclusion: DHS is a well-accepted implant for ITF with lower rate of complications only if proper surgical technique is followed. Good fracture reduction, adequate LFWT, ideal screw position and TAD less than 25mm are must to prevent implant failure. Level of Evidence: Level IV Keywords: Intertrochanteric fractures, DHS, Factors for failure
Highlights
One-half of proximal femur fractures are intertrochanteric fractures (ITF) out of which one-third are unstable
The mechanism of failure has been the cut-out of lag screw from the femoral head leading to varuscollapse of the neck-shaft angle, loss of reduction caused by excessive sliding of the lag screw, non-union, shortening of the affected limb and pain [5] .There are various factors responsible for the same such as age of the patient, bone quality, fracture pattern, stability of reduction, lateral femoral wall thickness(LFWT), lag screw position and tip-apex distance (TAD)
These 16 hips were the one, which went into implant failure and were evaluated further with respect to bone quality, fracture pattern, fracture reduction, LFWT, screw position and TAD
Summary
One-half of proximal femur fractures are intertrochanteric fractures (ITF) out of which one-third are unstable. Implant failure in form of screw cut out leading to varus collapse of neck shaft angle is associated with various factors like bone quality, fracture pattern, fracture reduction, lateral femoral wall thickness (LFWT), screw position and tip-apex distance (TAD). Factors under study were bone quality, fracture pattern, fracture reduction, LFWT, screw position and TAD, which were recorded and used for statistical analysis using SPSS. Implant failure in relation to unstable fracture pattern, non-anatomical fracture reduction, LFWT< 21.77 mm, screw placement in position apart from centre-centre or centre-inferior and TAD greater than 25mm was found to be statistically significant (p
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