The term sub-acute refers to the pain following the fracture of a bone rather than the actual fracture itself. It is the pain that occurs in the first few weeks as the bone and soft tissue begin to heal, according to Osteoporosis Canada.
When a bone is fractured, the pain felt immediately thereafter is acute pain. As the bone and soft tissue start to heal, there may be some sub-acute pain may present itself. According to Osteoporosis Canada, this happens because of the lack of movement that has occurred in order to get the bone to knit back together. There may also be some inflammation in the soft tissues surrounding the fracture that results in muscle stiffness.
While medication may help relieve some sub-acute pain, Osteoporosis Canada explains that a doctor may order physical therapy to begin moving those body parts that have been still. Physical movement assists in breaking down scar tissue that may have formed as a result of immobility and prompts muscles to begin working and strengthening. It also helps relieve any fear of moving the body part because of pain. Sub-acute pain from movement does not mean that further harm is occurring to the part of the body with a broken bone, but fear at this stage is a normal feeling. As physical movement increases, sub-acute pain should drop away and disappear.