Abstract
Introduction
The purpose of the present study was to identify risk factors for lag-screw cut-out following osteosynthesis of intertrochanteric fractures.
Materials and methods
The study was a case-control study using a sex and age matched control group. The fractures were classified according to Evans and OTA/AO classifications. Operative treatment was performed using dynamic hip-screw or cephalomedullary nailing systems. All patients were followed for at least 3–4 months postoperatively. The following risk factors were assessed: fracture type, quality of reduction by blinded assessment using a visual analogue scale, tip-apex distance (TAD) according to Baumgaertner, lag-screw positioning and other relevant additional risk factors in terms of walking ability, osteoporosis, cardio-vascular disease, neurological disease, diabetes, obesity, alcohol consumption and smoking.
Results
35 cases with lag-screw cut-out and 122 controls without cut-out, 124 women with a mean age of 84.9 (range: 51–95) years and 33 men with a mean age of 82.3 (range: 67–94) years were identified. Cut-out were significantly more frequent in OTA/AO type 31-A3 fractures (odds ratio (OR) 4.13; 95% CI: 1.50–11.36). The quality of reduction was significantly related to the risk of cut-out. The mean TAD was 26.5 mm in the case group and 21 mm in the control group. This difference was significant (chi square test p=0.046). Assessment of the lag-screw positioning showed that a central/central (OR 0.18; 95 % CI: 0.11–0.30) or central/inferior (OR 0.14; 95 % CI: 0.03–0.63) position was associated with a reduced risk for cut-out. None of the additional risk factors included in this study seemed to have any influence on the results.
Conclusion
This study showed that fracture type, quality of reduction, TAD and lag-screw positioning were the most important risk factors for cut-out.
