Bacteria, viruses, and fungi are all capable of infecting a joint. These tiny organisms invade and inflame the synovial membrane of the joint. Joint destruction with arthritis may be a local response to this infection. This condition is referred to as bacterial, infectious or septic arthritis.
As you have found out, acute septic arthritis in children can be present at birth. Early treatment is advised to prevent complications. In fact, a delay in diagnosis or treatment can lead to severe destruction of the hip joint.
The growth plate can be affected leaving the child with loss of motion. A difference in leg-length from side to side can occur. The combination of all these changes may mean the child will walk with a limp.
Studies show that a delay of four days or more increases the risk of a poor outcome. There are many other factors involved. Prematurity, type of bacteria, and the need for intensive care can affect prognosis, too.