What is a Segmental Fracture
A segmental fracture is defined by the presence of two distinct fracture lines that completely separate the cortical bone and isolate an intermediary bone segment between them. 1
Anatomic Definition and Characteristics
A segmental fracture creates a "floating" middle fragment that is completely disconnected from both the proximal and distal bone segments. This occurs when two separate fracture lines traverse the entire width of the bone, resulting in three distinct bone fragments rather than the typical two fragments seen in simple fractures. 1
Key Distinguishing Features
The intermediary segment is completely isolated with no cortical continuity to either adjacent fragment, differentiating it from "wedge" or "butterfly" fractures where a fragment remains partially attached. 2
The vascularization of the intermediate bone fragment is severely disturbed due to the double disruption of periosteal and endosteal blood supply, which has critical implications for healing. 3
Segmental fractures are classified as "complex" fracture patterns with at least two fracture lines and one or more fragments that span the full width of the bone. 2
Clinical Context and Mechanism
These fractures are always caused by high-energy direct trauma, typically from motor vehicle accidents, and are frequently associated with multiple injuries and significant soft tissue damage. 1, 3
In the tibia (the most commonly reported segmental fracture site), 80% are open fractures and 84% of patients sustain multiple trauma. 4
The mean length of the intermediary segment in tibial segmental fractures is approximately 14 cm, though this varies considerably. 1
Anatomic Location Classification
Segmental fractures are further classified by the anatomic zones involved: 1
- Distal-proximal metaphyso-metaphyseal (both fracture lines in metaphyseal regions)
- Proximal diaphyso-metaphyseal (one metaphyseal, one diaphyseal)
- Diaphyso-diaphyseal (both fracture lines in the shaft - most common pattern)
- Distal diaphyso-metaphyseal (one diaphyseal, one metaphyseal)
Critical Management Implications
The compromised vascularity of the middle segment creates high risk for nonunion, with 81% of delayed unions or nonunions occurring at the distal fracture site. 4
Bone healing is not simultaneous at both fracture sites in more than half of patients, requiring prolonged monitoring and often staged interventions. 1
There is a 48% incidence of compartment syndrome requiring fasciotomy, with 19% residual motor and sensory deficits despite prompt decompression. 4
The stabilization method must provide multilevel stability while minimizing further compromise to the already tenuous biology of the isolated middle fragment. 5