Acetabular fractures are fractures of the socket of the hip joint. They can occur in any type of automobile accident, including head on accidents and side contact accidents. The acetabulum is the socket portion of the pelvic bone that forms the joint with the upper end of the femur in the hip area. The acetabulum is smooth and cup-shaped. It contains the cartilage that acts as the lubricant to move the joint.
The acetabulum gets fractured when the ball of the joint pushes through the relatively thin socket. Side pressure or pressure coming up from the foot can cause this type of severe injury. The ball is often stuck within the socket following the accident. Normally, the ball gets broken; however, the acetabulum alone or both bones can be broken in the same accident.
An acetabular fracture is a high-energy incident that only occurs from falls from great heights or high speed motor vehicle accidents. There is often a great deal of trauma to the surrounding areas and other fractures besides the acetabular fracture. If the bone becomes weak because of osteoporosis, there is a higher incidence of these types of fractures due to weak bone, especially in the elderly.
When an acetabular fracture occurs, the hip must be stabilized so that the ball is held firmly within the socket and so that the socket itself is smooth and contoured. This can rarely be done without surgery and without replacing the entire joint. The surgeon must remove the bone chips from within the joint and create a space to hammer in an artificial acetabulum. The ball of the joint is removed and a new ball is cemented in. Surrounding ligaments and muscles must be repaired so that the joint is completely stable. Dislocation of a joint like this can occur and the joint must be replaced if it happens too often.
In the elderly, surgery is sometimes not done, even in cases where the alignment between the ball and the socket is not exactly right. These fractures heal fairly well, although the patient will not have perfect mobility.
Even if surgery is performed to fix the acetabulum, weight bearing must be minimal for up to three months following the surgery. Touch toe weight bearing is allowed but no more than that to avoid dislocating the joint or refracturing the acetabulum. After this, physical therapy can be done which can improve strength, mobility and balance.
Acetabular fractures have a poor term prognosis and have many complications. First of all, these are patients with multiple other injuries including head injuries, abdominal trauma, urologic trauma and spine or knee injuries. Blood clots of the leg and lung are relatively common, which can be fatal. Surgery itself can lead to bleeding complications, healing problems, nerve injury and infectious disease issues. After healing from the injury, the joint may still not work right and dislocations can happen just with stepping on the foot. Hip arthritis is a common secondary complication if the acetabulum isn’t completely replaced following the traumatic event.