A locking compression plate (LCP) can serve as an external fixation for fractured tibia. However, there is concern about the stability and endurance during partial weight bearing. This study was experimentally evaluated the effects of fracture gap sizes (1, 5, and 10 mm) on the stability and endurance of fractured tibia externally fixed with a 316L-stainless LCP. For stable fractured tibia (1-mm fracture gap), the large contact area of fracture surfaces resulted in nearly similar stiffness to that of intact tibia. The partial weight bearing is therefore possible. Whereas smaller contact area and no contact of fracture surfaces were observed for tibias with 5-mm and 10-mm fracture gaps, respectively. Their stiffnesses were significantly lower than those of intact tibia and tibia with 1-mm fracture gap. Thus, the partial weight bearing should be considered carefully in early phase of treatment. All LCP-tibial models were cyclically loaded beyond 500,000 cycles, that is, approximately 6 months of healing, without any failure of LCP. Thus, the failure of LCP is unlikely a critical issue for the present cases.
Chaosuan Kanchanomai and Vajara Phiphobmongkol
Chaosuan Kanchanomai, Panurungsit Muanjan and Vajara Phiphobmongkol
The effects of locking screw position (long column fixation—long distance between the nearest screws to the fracture—and short column fixation—short distance between the nearest screws to the fracture) and fracture gap size (1-mm and 8-mm transverse fracture gap) on stiffness and fatigue of fractured femur fixed with a locking compression plate (LCP) were biomechanically evaluated. The stiffness of 1-mm fracture gap models and that of intact femoral model were in the range of 270–284 N/mm, while those of 8-mm fracture gap models were significantly lower (155–170 N/mm). After 1,000,000 cycles of loading, no fracture of LCP of 1-mm fracture gap models fixed in either long column or short column fashions occurred. On the other hand, the complete fractures of LCPs of 8-mm fracture gap models fixed in long column and short column fashions occurred after 51,500 and 42,000 cycles of loading, respectively. These results suggest that the full weight loading may be allowed for the patient with 1-mm transverse femoral fracture fixed with an LCP. On the other hand, the full load of walking should be avoided for the patient with 8-mm transverse femoral fracture fixed with an LCP before adequate healing.