Minimally invasive osteosynthesis of adult tibia fractures by means of rigid fixation with anatomic locked plates

Abstract

Main principle of biological fixation by minimally invasive locked plate osteosynthesis (MILPO) in lower extremity long bone fractures is relative stability which is provided by using long plate with limited number of screws. Some biomechanical studies have been reported about this issue. However, clinical studies are still missing. The aims of this retrospective extended case series were to evaluate the clinical and radiological results of adult tibia fractures treated by MILPO and the effect of plate length and screw density on complication rates. Twenty tibia fractures in 19 patients (mean age 42.3 years) operated by MILPO were reviewed. According to the AO classification, diaphyseal and metaphyseal fractures without intraarticular extensions were simple and wedge-type fractures, whereas all intraarticular fractures were comminuted. Number of screws, cortices and empty screw holes proximal and distal to the fracture, plate-span ratio (plate length divided by overall fracture length), plate-screw density (number of inserted screws divided by number of plate holes), fixation failures, delayed or nonunion, malalignment and leg length discrepancy were documented. Mean follow-up was 16 (range 12-26) months. On average, 4 screws with 6 cortices were used both proximally and distally in all fractures. Only in diaphyseal fractures, one screw hole close to the fracture was omitted. Average plate-screw density and plate-span ratio were 0.68 and 4, respectively. Mean union time was 3 months. There were no cases of delayed or nonunion on the final follow-up. Plate bending was observed in one patient who had fair result. The remaining 18 (94.8 %) patients showed good and excellent results. Satisfactory results can be achieved despite low plate-span ratio and high plate-screw density in simple and wedge-type diaphyseal fractures of the tibia. Additionally, plate-screw density can be higher at metaphysis in intraarticular fractures, in which essential point is a perfectly stable fixation that provides early motion.

Fig. 1

Screw fixation technique used in the study. Kirschner wires are inserted into the bone through the most proximal and distal holes of the plate (a and b ). A second plate of similar size and length is placed through the same holes on the Kirschner wires and used as an external guide to localize the screw holes (c and d). The locking drill guide is inserted into the screw hole (e). Appearance of the leg after skin closure (f)

Fig. 2

Preoperative anteroposterior (a) and lateral (b) radiographs of 56-year-old female patient show a wedge type (AO 42-B1) right tibia fracture and associated fibula fracture at the same level. Tibia fracture was fixed with a 4.5 mm locking compression plate (c and d). One proximal screw hole close to the fracture was omitted. Plate-span ratio was 4.6 and plate-screw density was 0.66. 18 months postoperatively, anteroposterior (e) and lateral (f) radiographs showed uneventfully healing of the fracture without any complications