Acetabular fracture is a fracture of the acetabulum. Such fractures are usually indirect fractures resulting from accidental trauma. The fractures are usually treated by surgical osteosynthesis.
What is an acetabular fracture?
The acetabulum is the term used to describe the hip or pelvic socket. It forms the bony and crescent-shaped portion of the hip joint. The ilium (os ilium), pubis (os pubis), and ischium (os ischii) meet in the acetabulum. When the acetabulum is affected by a primary or secondary fracture, an acetabular fracture is present. A direct or primary fracture has a fracture gap of less than one millimeter. In a secondary acetabular fracture, there is a cleft of more than one millimeter between the fracture fragments, which is later closed with a callus by the processes of secondary fracture healing. Approximately ten fractures are distinguished on the acetabulum. The main subdivision is with the groups of horizontal and vertical fractures. The vertical fracture line with a statically intact pillar includes the fracture of the posterior acetabular rim, the fracture of the posterior pillar and the fracture of the anterior acetabular rim and pillar. A horizontal fracture line with destroyed statics but intact superior glenoid rim is present in T-shaped fracture and anterior horizontal posterior vertical fracture. A horizontal fracture line of long course separates fracture fragments of the acetabulum from the ilium and is present in fracture to the crista iliaca, fracture to the anterior margin of the ilium, and fracture into the sacroiliac joint.
Causes
Fractures are caused by direct or indirect force applied to a bony element. The causative force exceeds the elasticity and strength of the affected bone. Therefore, the bone yields to the pressure. We speak of a true fracture only when the bone has been completely severed. In the injury phase of the fracture, the fracture angle and the fracture line are established. In addition to the severity of the force, these parameters also depend on the angle of the applied forces. Acetabular fracture is usually caused by indirect force. The most common victims are accident victims whose knee hit the dashboard. The impact applied indirect compressive forces to the acetabulum. A direct blow to the greater trochanter of the femur is also a common cause. The knee can no longer be extended and thus buckles while walking during impact. Externally rotated hip joints primarily injure the anterior acetabular pile. Internally rotated hip joints injure the posterior one. Lower transverse fractures occur with an abducted hip joint, and high transverse fractures occur with an abducted hip joint.
Symptoms, complaints, and signs
In acetabular fracture, there are local signs of injury such as swelling or hematoma in the fracture gap. In addition to impaired function, there is often a more or less severe malalignment of the hip joint, which may be evident in the shortening of one leg. In such a hip luxation, the joint head lies outside the acetabulum. This phenomenon may cause femoral head necrosis or osteoarthritis of the hip joint as it progresses. Traumatic hip dislocation occurs predominantly in patients with stable bone structures. Hip dislocation in acetabular fracture occurs predominantly in the direction of the fracture. Because of their close proximity to the fracture, the sciatic nerve and femoral nerve are at risk for injury. If the sciatic nerve has been damaged by the fracture, in addition to severe pain, paralysis of the thigh muscles may be present and the flexor reflex may not be triggered. If the femoral nerve has been injured by the fracture or if it is trapped in the fracture gap, severe movement restrictions occur. Active flexion in the hip joint is thus no longer possible. Patients are also unable to straighten up from a lying position. Bony patella fractures or femoral head fractures are often present as concomitant injuries in impact trauma.
Diagnosis and course
The clinical picture and the mechanis of injury lead the physician to conclude that the acetabulum has been injured. During the clinical examination, the physician checks for blood flow as well as motor function and sensitivity of the affected area. The diagnosis is confirmed by x-rays.In addition to a pelvic overview exposure, special exposures such as an ala exposure and an obturator exposure are ordered. The obturator image is taken with a beam path of 45 degrees with the hip elevated. A computed tomography scan may complete the diagnostic workup. Differential diagnoses should exclude pure dislocation and femoral head fracture, femoral neck fracture, and pelvic fracture. Vascular and nerve damage must also receive differential diagnostic attention. Because steps often remain on the articular surfaces after acetabular fracture, many acetabular fracture patients later develop coxarthrosis. Therefore, the prognosis for complete healing is rather unfavorable.
Complications
Usually, an acetabular fracture results in severe swelling and pain at the affected site. The function of the hip joint is also disrupted. In some cases, malalignment occurs. If an acetabular fracture results in a trapped fracture gap, restrictions in movement occur. In this case, the affected person is sometimes dependent on walking aids and can no longer move around on his or her own. Because acetabular fracture usually occurs in a severe accident, trauma and fractures also occur in other parts of the body, which can negatively affect movement and life. The symptom can be relatively well diagnosed by the doctor and then treated. In most cases, the treatment is surgical and does not lead to further complications or discomfort afterwards. Various implants made of metal are used to position and hold the bones in place. The pain disappears after the surgery and is treated with painkillers beforehand. The treatment usually leads to a positive course of the disease. In older patients, the use of prostheses and artificial hip joints is necessary to avoid restriction of movement.
When should you see a doctor?
A doctor should always be consulted after a fall or accident. The medical professional can determine beyond doubt whether a fracture or break has occurred and refer the affected person to the appropriate specialist. If an acetabular fracture is suspected, the medical examination must not be delayed any longer because of the possible complications. Pain and swelling in particular require rapid treatment by the physician. If there is a suspicion of a multiple fracture, a trip to the emergency room is also an option. This always depends on the respective symptoms and the cause of the injury. For example, a contusion of the hip pelvis does not necessarily require medical treatment, while a complete fracture must be treated in the hospital in any case. Older patients usually receive a total hip replacement for an acetabular fracture. To ensure that the injury heals well, further medical examinations are usually necessary after the fracture has healed. In addition, medication sometimes needs to be adjusted to ensure a pain-free healing process.
Treatment and therapy
Treatment of an acetabular fracture is usually surgical. If the fracture is not accompanied by displacement of the bone fragments and has a fracture gap of less than two millimeters, conservative treatments take place. However, a cast for immobilization is usually not sufficient for this fracture. In most acetabular fractures, precise reduction and plating of the bone fragments is required to prevent the fracture from healing together in a malposition and thus prevent the acetabulum from losing its function. Osteosynthesis is usually the treatment of choice for a surgical treatment pathway. The procedure is used to restore full function to the bone. Osteosynthesis involves the anatomical reduction of the bone. Bone fragments that belong together are fixed in a relatively normal position. Stabilization is achieved by means such as Kirschner wire. If necessary, metal implants are placed to hold the fragments together properly. On older patients, after an acetabular fracture, total hip arthroplasty often takes place after the fracture heals. In other words, they receive an artificial joint replacement that replaces the entire joint. For their severe pain, acetabular fracture patients may receive appropriate pain medication.
Outlook and prognosis
The prognosis of acetabular fracture depends on the extent of the existing fracture and the patient’s general health. The more severe the bone damage and the older the patient, the less favorable the outcome. In a healthy person in middle age, the prognosis is good. After surgical intervention and correction of the bones, there is a regeneration process that lasts for several months. The surgery is challenging because the bones have to be repositioned precisely. This takes several hours under general anesthesia. If complications occur, the prospect of optimal recovery worsens. Patients often suffer from pre-existing conditions that weaken the organism and cause a delay in healing. Existing bone diseases can contribute to an unfavorable course. In some cases, freedom from symptoms is no longer possible. Targeted exercises and training sessions help patients after surgery to optimize their range of motion and slowly rebuild their bodies. Overloading must be avoided to prevent a relapse. Misalignment of the body and one-sided heavy loads can lead to secondary diseases, which should be avoided. Without treatment, there is no relief from the symptoms. The bones have been permanently damaged. The body has no means of self-healing to alleviate and heal the discomfort.
Prevention
To prevent acetabular fracture, strong direct or indirect force on the acetabulum should be avoided.
Here’s what you can do yourself
In younger patients, surgical treatment of an acetabular fracture is almost always successful and without complications. Patients best help themselves by seeing a doctor promptly in the event of a hip injury and by strictly following all medical instructions before and after a surgical procedure. In particular, do not overload the pelvic socket before the fracture is fully healed. In elderly patients, hip injury often occurs due to falls or other accidents in everyday life. In the case of an acetabular fracture, the use of prostheses and artificial hip joints is usually required to counteract a permanent restriction of movement. However, hip operations are very strenuous for seniors and are also not without risk. This group of people should therefore take preventive measures and actively contribute to accident prevention in everyday life. Only TÜV-approved stepladders should be used in the home. If motor skills or the sense of balance are already impaired, it is better not to use the upper sections of shelves and cupboards that cannot be reached without a climbing aid. In bad weather conditions and slippery roads, a walker should always be used as a precaution. If an injury to the hip still occurs, it is necessary to start rehabilitation in good time in order to regain mobility as fully as possible. Patients should find a good physical therapist and practice regularly with him or her.
