Pelvic and Acetabular Fracture Surgery
ABOUT THE ACETABULUM
Two parts comprise the hip joint: a ball on the upper end of the thigh bone, called the head of the femur; and a socket in the pelvis known as the acetabulum. The hip joint, like other joints, is made up of specialized structural elements that serve as precisely fitting, moving parts. The head of the femur rotates freely within the smooth, concentric surfaces of the acetabulum. An extremely low friction tissue, hyaline cartilage, lines this joint as well as others in the human body. The friction between two hyaline cartilage surfaces is much less than the best man-made bearing. Acetabulum fractures often result from automobile or motorcycle accidents, falls from great heights and industrial accidents, when a accidental strong force drives the head of the femur through the acetabulum.
ABOUT ACETABULUM FRACTURES
Fractures of the acetabulum disrupt the smooth surface and precise fit of the hip joint. If the bone is allowed to heal with large gaps and irregularities, severe abrasion to and the ultimate destruction of the cartilage will result. In some cases, the bone itself will show wear. The consequence: severe hip arthritis. Patients who develop arthritis have pain when walking, loss of hip motion, and limited functional capabilities. Fractures of the acetabulum cause internal bleeding from the broken bone and the surrounding injured soft tissues. Major blood vessels may be torn, causing severe bleeding. There can be damage to internal organs, such as the bowel or bladder. The nerves that provide sensation and muscle function to the leg or that control bowel, bladder and sexual function may also be impaired.
This is the traditional treatment technique and may involve traction to the leg. Recent medical studies however indicate non-operative treatment is best reserved for a minority of fractures (about 11%). Traction can prevent further displacement of the femur into the acetabulum but does not accurately reduce (reposition) acetabulum fractures and can lead to muscle atrophy and joint stiffness as well as a high incidence of arthritis.
Acetabulum Fracture Surgery
Surgery is required to obtain the best possible results for the majority of patients. Acetabulum fracture surgery preserves the hip joint by accurate reconstruction of the fractured bone. This reconstruction restores the smooth surface of the acetabulum and its accurate fit to the femoral head.
In the majority of cases, arthritis is prevented and there is close to normal hip function.
Prior to surgery, patients undergo a comprehensive series of tests to obtain baseline data essential to the surgeon, medical specialists, anesthesiologist and other members of the health care team. These include an electrocardiogram, blood and urine tests, and a history and physical examination to determine any past or existing medical problems. X-rays are also obtained, including 5 standard pelvis views and CT (computed tomography) scans. Sophisticated computer software allows the technologist to make cross-sectional CT scans into three-dimensional images. These x-rays enable the surgeon to determine the fracture pattern and precise degree of displacement and to plan the surgical approach. (Figures 3 & 4).
For best results, surgery should take place within seven days of injury. The potential for difficulties and complications increases after three weeks.
Depending on the fracture pattern, one of three surgical approaches will be chosen which will give the best access for reconstruction of the acetabulum. These include the Kocher-Langenbeck approach (posterior approach), the Ilioinguinal approach (simultaneous access to both anterior & posterior portions of the pelvic ring), and the Extended iliofemoral approach (lateral approach). The patient is placed on a special operating table that applies traction to the leg during surgery and assists in reducing the fracture.
Surgery to repair acetabulum fractures is called open reduction and internal fixation. Open refers to making an incision that exposes the broken bone fragments to view. Reduction refers to the process by which the surgeon uses specially designed instruments to grasp the bone fragments and manipulate them into their normal position. Internal fixation occurs when metal screws and plates are used to hold fractured bone fragments to the unbroken portions of the pelvis.
Screws and plates (thin strips of metal with holes to accommodate screws) fix fractured bone fragments together. Typically made of stainless steel, these implants do not react with body fluids or cause an allergic response. Implants made of vitallium or titanium are also safe and effective. .
The operation itself takes between two and five hours, with a blood loss ranging from 100 to 2,000 cc’s. A blood transfusion may be necessary but only as a last resort after using the cell saver. The cell saver collects lost blood, washes the blood cells and returns them to the patient’s circulation. During surgery, drains will be placed in the surgical site, which will be removed two to three days post-operatively. The dressing covering the incision will be checked on a regular basis and changed or removed two to three days after surgery. Patients wear compression boots and anti-embolus stockings to prevent blood clots from forming in the large veins or veins traveling to the lungs.
After several months, the solidly healed bone will once again support normal function. The cartilage will also heal, filling in the now reduced fracture lines. And though the metal plates and screws implanted during surgery will become superfluous, they are also harmless. Typically, they will be left in place to avoid unnecessary surgical removal.