P. Schandelmaier

Minimally invasive plate osteosynthesis: does percutaneous plating disrupt femoral blood supply less than the traditional technique?

OBJECTIVES/HYPOTHESISnProximal and distal femur fractures have traditionally been treated with open reduction and internal fixation through a standard lateral approach. New, minimally invasive internal fixation techniques, however, have been developed in an effort to devascularize the bone less than the traditional method. The purpose of this study was to determine whether a minimally invasive percutaneous plating technique better preserves bone vascularity relative to the traditional method by comparing the effect of the two approaches on the blood supply of the distal femur using silicone arterial dye injection in a cadaveric model.nnnSTUDY DESIGN/METHODSnTen fresh human cadavers underwent lateral conventional plate osteosynthesis (CPO) through a standard lateral approach on one side and minimally invasive plate osteosynthesis (MIPO) through two three-centimeter incisions on the contralateral side. After injection of silicone dye, a dissection was performed bilaterally to identify the femoral perforating and nutrient arteries.nnnRESULTSnAll MIPO specimens showed intact perforating and nutrient arteries, whereas the CPO specimens had a variable incidence of vessel disruption. The MIPO group demonstrated better periosteal perfusion in each of the cadavers and improved medullary perfusion in 70 percent of the MIPO specimens compared with the CPO specimens.nnnCONCLUSIONnA percutaneous minimally invasive plating technique disrupts the femoral blood supply less than the traditional open method. Such minimally invasive methods may be more advantageous biologically than the traditional method.

The mechanical effect of blocking screws ("Poller screws") in stabilizing tibia fractures with short proximal or distal fragments after insertion of small-diameter intramedullary nails.

OBJECTIVES/HYPOTHESISnTo evaluate the mechanical effects of medial and lateral blocking screws in supplementing intramedullary nail fixation of high proximal and low distal tibial fractures treated with small-diameter intramedullary nails.nnnSTUDY DESIGNnIntact fresh human cadaveric tibiae were sectioned to provide ten distal segments measuring seventy millimeters and ten proximal segments measuring ninety millimeters. In the distal segments, stainless steel solid eight-millimeter tibial nails were advanced to eight millimeters from the ankle joint. Two transverse and one anterior-posterior (AP) locking screw were inserted using a custom-made jig. The same jig was used for the placement of a medial and a lateral blocking screw (BS) in the AP direction, nine millimeters above the superior most interlocking screw and eight millimeters distal to the lower end of the segment. In the proximal segments, two interlocking screws (both static and dynamic screws) were placed in a medial-lateral direction with the use of the insertion handle. A jig was used for placement of a medial and a lateral BS in the AP direction, nine millimeters below the lower transverse interlocking screw and sixteen millimeters proximal to the lower end of the segment. The bone-implant construct (BIC) was embedded and fixed in a materials testing machine. The BICs were loaded in the medial-lateral direction at a distance of 185 millimeters from the nail ends with loads from -150 newtons to + 150 newtons. Force-displacement curves were recorded before and after insertion of the BSs.nnnRESULTSnIn proximal BICs, the addition of BSs decreased the deformation of the BICs 25 percent, from 8.9 +/- 1.9 degrees [mean +/- standard deviation (SD)] in the control group to 6.8 +/-1.1 degrees in the BS group (mean +/- SD) (p < 0.0001). In distal BICs, the addition of BSs decreased the deformation of the BICs 57 percent, from 9.5 +/- 1.4 degrees (mean +/- SD) in the control group to 4.0 +/- 1.0 degrees in the BS group (mean +/- SD) (p < 0.0001).nnnCONCLUSIONSnThe study suggests that medial and lateral blocking screws can increase the primary stability of distal and proximal metaphyseal fractures after nailing and can be an effective tool for selected cases that exhibit malalignment and/or instability.

Distal femoral fractures and LISS stabilization

In recent years, the technique of surgical stabilization in the distal femur has changed. This change decreased the number of non unions and the need for bone grafting. Minimally invasive surgical techniques with a submuscular plate placement have replaced the emphasis on anatomical reduction in the shaft area. Reconstruction of complex articular injuries has been simplified by more direct visualization of the articular surface with the lateral peripatellar approach. Problems remaining are surgical technique and implant considerations. The Less Invasive Stabilization System (LISS) simplifies the surgical technique for percutaneous plate osteosynthesis. An insertion guide is used to insert monocortical, self-tapping screws through a stab incision. A thread in the plate provides the angular stability for the anchoring of these screws. In extra-articular fractures and simple intra-articular fractures, the distal femoral nail permits intramedullary stabilization. A spiral blade improves fixation of the distal femoral condylar block. Despite the enhanced surgical technique and implant possibilities, a great number of patients show a functional deficiency. These are particularly patients with complex intra-articular fractures. The fatigue failure of the osteoporotic implant-bone construct is a problem in elderly patients. The LISS represents a good option to avoid the addition of bone cement to an osteosynthesis.

Less Invasive Stabilization of Complex Tibial Plateau Fractures : A Biomechanical Evaluation of a Unilateral Locked Screw Plate and Double Plating

Objective: To compare the vertical subsidence in a bicondylar tibial plateau fracture model stabilized either by a unilateral locked screw plate (LSP) or by double plating. Design: Biomechanical cadaver study. Intervention: A 41-C1 fracture model was created in eight pairs of fresh-frozen human cadaver tibiae. Stabilization was performed either by open reduction and internal fixation (ORIF) using a lateral L-buttress plate and a medial four-hole, one-third tubular antiglide-plate or by a lateral LSP. Four load levels (400N, 800N, 1200N, 1600N), each with five cycles, were consecutively applied to the medial plateau. Main Outcome Measurements: The vertical plastic deformation at the end of each cycle was the main parameter of interest. Statistical analysis was performed with the two-way ANOVA test for repeated measurements. Each individual loading level was analyzed separately using Student t test. Results: In one pair, both fixation techniques failed at the first loading cycle of 1200N. One ORIF fixation failed at the first loading cycle of 1600N. The average plastic vertical subsidence was 0.40 mm (LSP) and 0.25 mm (ORIF) at 400N (P = 0.291), 0.83 mm (LSP) and 0.81 mm (ORIF) at 800N (P = 8.82), 1.06 mm (LSP) and 0.96 mm (ORIF) at 1200N (P = 0.98), and 1.54 mm (LSP) and 1.14 mm (ORIF) at 1600N (P = 0.53). Vertical subsidence depended on the applied load (P = 0.002), but not on the method of fixation (P = 0.236). Conclusion: Both fixation techniques have a high resistance to vertical subsidence even with loads exceeding the average body weight. No statistically significant difference was seen between the two methods of fixation.

Nonreamed interlocking nailing of closed tibial fractures with severe soft tissue injury.

Closed tibial shaft fractures with severe soft tissue trauma require urgent surgical treatment to minimize complications such as soft tissue necrosis, infection, compartment syndrome, and nonunion. Although time to union and complications are similar to open tibial fractures, these injuries often are treated as low energy closed fractures. The method of internal fixation depends not only on the fracture pattern, but also on the condition of the soft tissues. Unlike plate osteosynthesis, the authors believe that virtually all complex closed tibial fractures may be treated with an unreamed tibial nail if proximal and distal interlocking is possible. With severe closed soft tissue trauma (Grades 2 and 3), an unreamed nail may have biologic and mechanical advantages. In a prospective study, 21 closed tibial shaft fractures with severe soft tissue trauma (Grades 2 and 3) were treated with an unreamed nail. The mean followup was 29 months. All fractures healed in an average time of 23 weeks. However, 3 patients required a bone graft, and in 3 patients the fixation was revised. One infection occurred after an exchange reamed nailing. Because of the low infection and low nonunion rate, the authors recommend unreamed interlocking tibial nails for closed tibial shaft fractures with severe soft tissue trauma.

Biomechanical study of nine different tibia locking nails.

We compared different nail types within the Bone/Implant-Complex to look for differences in stiffness for axial load, bending and torsion of the System. We simulated comminuted mid shaft fractures by a 2-cm defect osteotomy in paired human cadaver tibiae. We fixed tibiae with one of nine different interlocking nails [AO Unreamed Tibial Nail 9 mm (UTN9), AO Unreamed Tibial Nail 8 mm (UTN8), Russell & Taylor Delta Tibial Nail 9 mm (RTD), Russell & Taylor Reconstruction Tibial Nail 11 mm (RTR), Brooker & Wills Tibial Nail 11 mm (B&W), Grosse & Kempf Tibial Nail 11 mm (G&K), AO Universal Tibial Nail 11 mm (AOU), Klemm & Schellmann Tibial Nail 11 mm (K&S), and Börner & Mattheck Tibial Nail 11 mm (B-M)] according to the manufacturers recommendations. In torque testing the unslotted nails (UTN9, UTN8, RTD, RTR, B&W) showed significantly higher stiffness compared to the slotted nails (G&K, AOU, K&S, B-M). Compared to intact bone, both groups of nails were significantly less stiff. In axial load testing large diameter nails interlocked by large diameter interlocking bolts (G&K, K&S, B-M) showed significantly higher stiffness. For A-P bending no significant differences between implants were found, but isolated bones showed significantly higher A-P bending stiffness. In varus-valgus bending large diameter nails (RTR, G&K, K&S, B-M) showed significantly higher bending stiffness compared to low diameter (UTN8, B&W) implants.

Superior results of tibial rodding versus external fixation in grade 3B fractures

From 1987 to 1993, 41 Grade 3B open tibial shaft fractures were treated with the unreamed tibial nail or an external fixator. The method of treatment was left to the choice of the operating surgeon. Three below knee amputations were performed; three patients died; and three were lost to followup. Thirty-two patients were observed until union or for at least 1 year. There were no significant statistical differences between the two groups with respect to fracture type, fracture location, age, gender, or accompanying injuries. The unreamed tibial nail group showed significantly better results regarding time to full weightbearing, number of reoperations, isolated bone grafting, walking range, and average Karlström and Olerud score. Time to bony union, infection, and nonunion were not significantly different between the groups.

Outcome of tibial shaft fractures with severe soft tissue injury treated by unreamed nailing versus external fixation

MATERIALSnBetween 1987 and 1991, 114 fresh tibial shaft fractures with severe soft tissue injury, which met the inclusion criteria, were treated and retrospectively reviewed. There were 48 cases in the unreamed nail (unreamed tibial nail (UTN)) group and 66 cases in the external fixation (EF) group.nnnMETHODSnSoft tissue injury was classified by the Gustilo and Tscherne methods. There were 18 AO type A, 56 type B, and 40 type C fractures. There were no significant difference in fracture type, soft tissue injury, age, and additional injury between the groups. Outcome was assessed using the Karlström score after 28 months.nnnRESULTSnThere were a significantly higher number of reoperations in the EF group. Mean time to bony healing was 25.8 weeks. In the EF group, there was a 26% rate of pin tract infection, whereas 19% of cases had bolt breakages in the UTN group. In the UTN group, 40% had good results, compared with 27% in the EF group. In the UTN group, there were significantly fewer ante- and recurvatum deformities of more than five degrees.nnnCONCLUSIONSnTreatment of tibial fractures by UTN, compared with EF, gave a lower reoperation rate and better functional outcome.

The topography of the perforating vessels of the deep femoral artery

This study evaluated the anatomic relationship between the femur and the vessels that arise from the deep femoral artery, that is, the perforating arteries and the nutrient artery. Blue silicone dye was injected through the common femoral artery in 20 fresh human cadavers. An anteromedial and a posterolateral dissection were performed to identify the femoral perforating arteries and the nutrient artery of the femur. The length of the femur and the distances between the tip of the greater trochanter and the perforating arteries and nutrient artery were measured. This study showed that a reliable, clinically applicable topographic relationship exists between the femur and the perforating arteries and the nutrient artery.