The acetabulum is part of the pelvic bone and is also known as the pelvic or hip socket. It is crescent-shaped when viewed from above and forms the center of the hip joint. All three parts of the pelvic bone, namely the ischium, pubic bone and ilium, meet here and together form the joint surface. The femur moves in the acetabulum with every movement. Its integrity is therefore essential for locomotion, sport and sitting.
An acetabular fracture is a joint fracture that has a special position in a pelvic fracture. An acetabular fracture is usually the result of severe direct or indirect force. This occurs, for example, when falling from a great height and landing on the feet. The head of the femur is abruptly pressed against the acetabulum, which rarely remains without consequences.
An indirect impact can also occur in a rear-end collision when the knee strikes the dashboard. An acetabular fracture often occurs together with a dislocation of the hip joint. In around 15 percent of cases, the sciatic nerve is also injured.

The acetabulum (hip socket) is formed from the pubic bone, ischium and ilium © Henrie | AdobeStock
The symptoms of an acetabular fracture are very similar to the general symptoms of a pelvic fracture. They include
- Severe pain,
- swelling and
- possibly an unstable pelvic bone.
Bruising may also occur in the affected areas. In some cases, the legs may vary in length due to the pelvic fracture. Due to the severe pain, walking is usually restricted or impossible.
As an acetabular fracture is usually the result of a serious accident and the ability to walk is impaired, the ambulance or emergency doctor is usually called and further treatment is provided in hospital. There, the doctors on duty in the emergency room and trauma surgery department will take care of the next steps. First of all, detailed questions are asked about the course of the accident and the patient's medical history (anamnesis):
- How did the accident occur?
- How can the pain be described?
- Were there any previous complaints?
- Are previous damage or injuries known?
The questioning of the patient is followed by various examinations.
Physical examination
The physical examination in particular is very important and must be carried out thoroughly. This involves checking for
- external injuries,
- bruising or
- malpositions of the joint
of the joint. A shortening of the leg on the affected side and an outward twist (external rotation) are also important indications of a bone injury near the hip.
The pelvis is then carefully palpated to detect painful pressure points and possibly even signs of a bone injury (crepitatio = crackling). The stability of the pelvis can also be assessed. However, extreme caution is required during the examination as it is often very painful for the patient and should be avoided.
To rule out internal bleeding, a rectal examination with a finger is also not unusual. In addition, routine
- sensitivity,
- motor function and
- blood circulation
of the legs and feet are also routinely checked to ensure that possible nerve damage is not overlooked.
Imaging procedures
An ultrasound examination (sonography) can be used to examine the abdominal cavity for possible injuries to the internal organs. An ultrasound scan can also reveal the presence of free fluid - such as blood - in the abdomen. An ultrasound should always be carried out in the emergency room (shock room), particularly in the event of serious traffic accidents or a fall from a great height. This is part of the initial examination and determines the urgency of further treatment. Injuries to internal organs can be life-threatening and generally require emergency surgery. An isolated acetabular fracture is not normally life-threatening.
In order to diagnose an acetabular fracture, an X-ray of the pelvis is important. This allows the exact location of the fracture to be localized and an assessment to be made as to whether the fracture is unstable or stable. In a stable fracture, the pieces of bone are barely displaced, whereas in an unstable fracture there is considerable displacement. In the case of smaller and non-displaced fractures, it may not be possible to visualize them reliably on a normal X-ray, although this does not rule out a fracture.
If a bone fracture is suspected due to the history and severe pain, a computer tomography (CT) scan should be performed. This allows precise conclusions to be drawn about the extent of the injury. In addition, the condition of the soft tissue can also be better assessed with the help of a CT scan. This examination makes it easy to see the extent to which a bruise has spread.
Further examination methods for an acetabular fracture
As already described in detail, the most important examination for acetabular fractures is computer tomography. However, additional special examinations may be necessary to detect other injuries to neighboring organs and organ systems. Accompanying injuries can, for example
- the urinary bladder,
- the urethra or
- the urethra or the ureter as well as
- the rectum or
- the female internal reproductive organs (ovaries and uterus).
are affected. First of all, examinations must be carried out by specialist doctors who deal with the respective possible concomitant injuries. The urologist is responsible for the urinary bladder, urethra and ureter, the visceral surgeon for the colon and rectum and a gynecologist for the reproductive organs. If concomitant injuries are suspected, the relevant specialists will then arrange further examinations if necessary.
For example, if injuries to the urinary tract and kidneys are suspected, a so-called excretory urography can be arranged. For this purpose, the patient is administered a contrast agent, which is injected into a vein. This contrast medium is excreted by the body via the kidneys and is visible on the X-ray image.
An acetabular fracture is a serious injury that requires surgery in almost all cases . This is also done with the aim of preventing premature joint wear. After all, the acetabulum is of central importance and bears the main load when a person walks upright.
For this reason, patients usually have to remain in bed for several weeks after the operation. If there is a multiple pelvic fracture in addition to the acetabular fracture, it may take several months before the patient can put weight on their legs again.
Acetabular surgery following an acetabular fracture is a demanding procedure. For this reason, the operation should be performed in specialized centers. During the operation, the broken bone parts are fixed with plates and screws or an external stabilizer. During the acute phase, anesthetics are mainly used.
The pain-relieving medication allows the patient to perform physiotherapy exercises. Many painkillers have sedative properties, which have a positive effect on patients with an acetabular fracture.

Surgery for an acetabular fracture involves fixing the bone parts with screws and plates © Joel bubble ben | AdobeStock
An acetabular fracture is a comparatively complicated fracture for which a long regeneration phase is important. It can take weeks or months before the patient can put weight on their legs again as usual. However, this long period is important in order to prevent a secondary deformity or incorrect healing. Secondary" refers to a good position of the broken bone parts directly after the operation, which then shift again if the patient puts weight on them too early.
Nevertheless, it is also important to start mobilization early in the case of a pelvic fracture in order to reduce the risk of thrombosis and prevent muscle breakdown. In order to avoid the above-mentioned complications, it is essential that this is carried out under physiotherapeutic guidance in the case of an acetabular fracture. This allows the extent of the load to be controlled and managed and helpful tips and tricks to be given.
At the beginning of physiotherapy, movement therapy in water is ideal for strengthening the muscles and regaining a normal range of movement, even if the leg must not be fully loaded at this stage.
The programme consists mainly of passive and assisted active mobilization. The patient performs isometric exercises with the help of the physiotherapist. These exercises initially involve tensing the muscles without active movement. Later, concentric exercises are performed - i.e. exercises in which the patient tenses the muscles during movement.
As the therapy progresses, the patient can continue with
- rehabilitation on an ergometer and special exercises
- special exercises for the lumbar and lower back area and the hip joint.
begin. Only after consultation with the attending physician should the patient start light sports once the rehabilitation measures have been completed.
In summary, it can be said that an acetabular fracture is rarely a life-threatening injury. However, treatment is usually surgical and the healing process requires a lot of patience. Rehabilitation lasting several months and limited ability to work must be expected. But patience pays off in the vast majority of cases.