This young patient suffered a high-energy injury resulting in a comminuted, intra-articular, open fracture of a long bone. Accepted practice is that such injuries require immediate and thorough washout with soft tissue debridement if appropriate[2] and [3]. As there were concerns regarding the stability of the fracture fragments only minimal soft tissue debridement was performed.
We maintain that the gas locules seen on the CT scan at 24 h represent air introduced via the open wound at the time of injury. Subsequent introduction, particularly at the time of initial wound management is possible though we feel less likely as only minimal debridement was performed and fracture displacement in theatre would have been much less than that at the time of injury. For the same reason, the passage of air into the ankle due to elevation of the injured leg is unlikely and, in addition, the fracture and joint would have been occluded by haematoma by this time.
Another possibility is that the gas locules represent nitrogen bubbles “sucked” into the joint from the circulation due to production of a vacuum within the joint. The volume of gas and its presence between the fracture fragments suggests that this is not the case, however, and the disruption of the joint by fracture would reduce the negative pressure that could be generated. In addition if the gas has originated from the ankle joint it might reasonably be expected to spread out in a concentric manner from the joint. The possibility of gas forming organisms in the wound is unlikely due to the short time between injury and CT (less than 24 h) and there were no signs or symptoms of local or systemic infection at any stage.
We hypothesise, therefore, that air entered the fracture site via the open would at the time of maximum displacement as the tibia was deformed at the point of impact, when the skin was broken. Subsequent relative reduction of the fracture as the deforming force lessened trapped the air within the leg and “pumped” the air to locations distant to the open wound including the ankle joint.
If a fluid such as air can be pumped distant from the open wound, other fluids could likewise be translocated, potentially carrying with them contaminating organisms. Liquid contamination would, of course, not be distinguishable by CT and the presence of gas in this case could be considered a serendipitous surrogate indicator of the mechanism occurring. The gas seen so far from the joint is a salutary reminder of the huge forces required to shatter healthy bone into many fragments. Much of the energy would also have been dissipated into the adjacent soft tissues, and the extent of soft tissue injury is often underestimated.
We maintain that the gas locules seen on the CT scan at 24 h represent air introduced via the open wound at the time of injury. Subsequent introduction, particularly at the time of initial wound management is possible though we feel less likely as only minimal debridement was performed and fracture displacement in theatre would have been much less than that at the time of injury. For the same reason, the passage of air into the ankle due to elevation of the injured leg is unlikely and, in addition, the fracture and joint would have been occluded by haematoma by this time.
Another possibility is that the gas locules represent nitrogen bubbles “sucked” into the joint from the circulation due to production of a vacuum within the joint. The volume of gas and its presence between the fracture fragments suggests that this is not the case, however, and the disruption of the joint by fracture would reduce the negative pressure that could be generated. In addition if the gas has originated from the ankle joint it might reasonably be expected to spread out in a concentric manner from the joint. The possibility of gas forming organisms in the wound is unlikely due to the short time between injury and CT (less than 24 h) and there were no signs or symptoms of local or systemic infection at any stage.
We hypothesise, therefore, that air entered the fracture site via the open would at the time of maximum displacement as the tibia was deformed at the point of impact, when the skin was broken. Subsequent relative reduction of the fracture as the deforming force lessened trapped the air within the leg and “pumped” the air to locations distant to the open wound including the ankle joint.
If a fluid such as air can be pumped distant from the open wound, other fluids could likewise be translocated, potentially carrying with them contaminating organisms. Liquid contamination would, of course, not be distinguishable by CT and the presence of gas in this case could be considered a serendipitous surrogate indicator of the mechanism occurring. The gas seen so far from the joint is a salutary reminder of the huge forces required to shatter healthy bone into many fragments. Much of the energy would also have been dissipated into the adjacent soft tissues, and the extent of soft tissue injury is often underestimated.
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