Table 2: Different causes of SBDs and consequences of untreated SBDs.

Causes of SBDs
 Trauma injuriesBlast injuries:
these types of injuries are very common amongst military personnel. The injury that results from bomb or explosive detonation is of significant nature because it not only affects the skeletal structure, but also the musculature, blood supply, and nervous system.
Fractures and sport injuries:
these types of fractures are often segmental and are characterized by shattered, fragmented pieces of bone. After the broken pieces are surgically removed, a gap is left between the opposite extremities.

 DiseasesThese include bone cancer (requiring tumor resection and reconstruction), osteoporosis, osteoarthritis, generic infections, congenital deformity corrections, and pathological degenerative bone destruction. The commonality among these diseases is that the bone is either abnormally weak or needs to be removed to prevent spreading of the disease. As a result, large segments of bone are missing or are surgically removed and need to be replaced.

Complications from untreated SBDs
 MalunionThe two fractured bone ends are able to bridge, although they are not symmetrically aligned. As a result, the new bone is still susceptible to fracture. This is commonly seen in undiagnosed/untreated fractures and leads to loss of bone function.

 Nonunion (pseudarthrosis)The two fractured bone ends are not able to heal, and no bridging occurs between them. This is seen in critical defects. Another case of nonunion is observed when there is too much movement between the bone ends (insufficient surgical fixation) and the callus is never able to ossify and harden. In many cases, surgical intervention is needed to resolve the problem and avoid further loss of bone function.