The Biomechanical Study on the Stability of the Knowles Pinning in the Intertrochanteric Fracture of the Femur

The stability of the Knowles pinning in the intertrochanteric fractures of the femur was studied to determine which state would best support the load and compared with that of others. Experimental stable and unstable four-part fractures of the intertrochanteric region were produced by manual straight cut in 20 embalmed adult femora. These fracture were stabilized using accurate or inaccurate reduction combined with implant of Knowles pin parallel to calcar femorale or femoral neck. Those specimen were examined for the maximum load supported with the Universal Testing Machine. The results obtained are as follows: 1. Those femora of stable fracture with accurate reduction and Knowles pinning parallel to calcar femorale were failed by load of 140±13kg. 2. Those femora of stable fracture with accurate reduction and Knowles pinning parallel to femoral neck were failed by load of 120±11 kg. 3. Those femora of stable fracture with minimal displacement and Knowles pinning parallel to calcar femorale were failed by load of 110±10.4kg. 4. Those femora of unstable four-part fracture with accurate reduction and Knowles pinning parallel to calcar femorale were failed by 80±9kg.