# A Review of the Impacts of Implant Stiffness on Fracture Healing
## 3 Clinical Problems in Bridge Plating for Fracture Treatment
Specifically, within a population of low-energy fractures treated using the minimally invasive plate osteosynthesis (MIPO) technique, a trend was observed where longer plates were associated with a lower rate of non-union, although this trend did not achieve statistical significance. Factors such as the total number of plate holes, average bridging length, ratio of bridging length to plate length, and fixation crossing the fracture line were also not significantly associated with non-union. Comparative studies between MIPO and traditional locking compression plates were conducted in previous studies [38; 42]. [PERSON] et al. found a significant decrease in the rate of non-union for the MIPO group in comparison to the group treated with open reduction [38]. Meanwhile, the other study reported no significant difference in postoperative complications between the two methods [42]. MIPO has gained popularity as a technique for managing distal femoral fractures. Theoretically, MIPO allows for better preservation of the blood supply, maintenance of the fracture hematoma, and reduces soft tissue damage. It has been reported in a mouse fracture model that the starting point for fracture repair is mesenchymal cell proliferation from the periosteal area near the fracture site and differentiation into osteoblasts [4], and there is a consensus that maintenance of blood flow and protection of the periosteum is important. However, the effectiveness of MIPO for the treatment of other long bone fractures remains uncertain, with studies presenting mixed results. This indicates that additional research is needed to fully understand the potential advantages of MIPO. The preferred choice is the longest anatomically feasible plate, as these plates can be applied [14; 35]. This approach preserves the biology, ensures a more uniform stress distribution, and diminishes implant fatigue. Using a greater number of screw fixings than necessary is not required. Moreover, it is crucial to maintain low screw-fill levels and minimize stress concentrations [14; 43]. [PERSON] et al. found a significant link between higher rigidity scores and an increased likelihood of non-union, where rigidity score encompassed factors such as proximal screw density, plate material, and the number of screws traversing the fracture site [37]. Moreover, constructs utilizing solely locking screws were correlated with a greater incidence of non-union compared to hybrid constructs that combine locking and non-locking screws [40]. Notably, a higher density of proximal screws and overall screw density was significantly related to elevated non-union rates, specifically within the group of patients with low-energy fractures [44]. This particular relationship was not observed in other studies examining similar variables [36; 38]. The plate construct's effective length is defined as the distance between the initial screws located on either side of the fracture. It has been proposed that a longer effective length may lead to a reduction in non-union rates. A previous study found strong evidence supporting a significant correlation between a greater effective length and lower non-union rates [39]. This correlation was established by measuring the average number of unfilled holes next to the fracture. However, this relationship was not observed when measured in millimeters [39]. In contrast, other studies did not discover a significant connection between the effective length and the occurrence of non-union [38; 40].