Abstract
Summary
For injuries to the lower leg or forearm, supplemental support from soft tissue compression (STC) with a splint or brace-like system and combined with external fixation could be done effectively and quickly with a minimal of facilities in the field.
Introduction
Soft tissue compression (STC) in functional braces has been shown to provide rigidity and stability for most closed fractures, selected open fractures and can supplement some other forms of fracture fixation. However, soft tissue injuries are compromised in war injuries. This study was designed to evaluate if STC can provide adequate rigidity and stability either with, or without other forms of fixation techniques of simple fractures or bone defects after standardised soft tissue defects. The load was applied either axially or in bending as the bending configuration is more like conditions when positioned on a stretcher in the field.
Methods
A simple, oblique fracture was created in 23 cadaveric femurs, 23 tibiae and fibulae, 22 humeri and 22 radii and ulnae of intact limb segments. The weight of each intact limb segment was measured. Cyclic axial loads (12 – 120N) were applied for each progressive condition: intact limb, mid shaft osteotomy, a lateral 1/4 circumferential soft tissue defect, 1/3 circumferential defect and finally, 3 cm bone defect. Limbs were randomly assigned to be stabilised be either plate and screw (PS), intramedullary rod (IR) or external fixation (EF). Testing with and without STC in a brace was performed after each condition. In an additional 36 forearms, bending rigidity was measured using a modular fracture brace with external fixation. The bone and the soft tissue weighed separately and the ratio of soft tissue to bone was calculated. ANOVA multi-variant analysis corrected for multiple comparisons was used to compare the axial rigidity between the different conditions tested.
Results
There was no significant difference in axial rigidity for humerus or femoral shaft fractures treated by any of the methods related to the degree of soft tissue damage. Femurs, tibias and humeri with a 3 cm bone defect were best stabilised with IR. Forearms with a 3 cm bone defect were best stabilised with PS. Progressive increase in soft tissue defects did create progressive loss in rigidity in forearms and legs, but the most dramatic loss occurred with the bone defect and ST defect. The rigidity of IR and EF in legs decreased over 50% with bone defect, and about 20% of that was restored with STC. The rigidity of IR and EF in forearms decreased almost 79%, and about 21% of that was restored with STC. The increase in resistance to bending in the forearm was most significantly improved by STC.
Discussion/Conclusions
Invasive types of surgical intervention provide the best rigidity to fractures, regardless of the presence of or size of a soft tissue defect. In general, use of PS and IR and application of conventional types of braces to achieve STC is not practical in the field. EF, however, can be applied quickly and easily with a minimal of facilities in the field and can be applied in such a way that no foreign bodies end up in the contaminated wound. For injuries to the leg or forearm, supplemental support from STC with a splint or brace-like system could be effective.
