Acetabular fracture

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Acetabular fracture
AcetabularfracX.png
Acetabular fracture as seen on plain X-ray

Fractures of the acetabulum occur when the head of the femur is driven into the pelvis. This injury is caused by a blow to either the side or front of the knee and often occurs as a dashboard injury accompanied by a fracture of the femur. [1]

Contents

The acetabulum is a cavity situated on the outer surface of the hip bone, also called the coxal bone or innominate bone. It is made up of three bones, the ilium, ischium, and pubis. Together, the acetabulum and the head of the femur form the hip joint.

Fractures of the acetabulum in young individuals usually result from a high energy injury like vehicular accident or feet first fall. In older individuals or those with osteoporosis, a trivial fall may result in acetabular fracture.

In 1964, French surgeons Robertt Judet, Jean Judet, and Emile Letournel first described the mechanism, classification, and treatment of acetabular fracture. They classified these fractures into elementary (simple two part) and associated (complex three or more part) fractures.

Judet-Letournel classification

Elementary fractureDescriptionAssociated fracturesDescription
Posterior wallThis is the most common variety of acetabular fracture. It typically occurs due to dashboard injury; when a person travelling in a vehicle involved in a head-on collision, the force applied over the flexed knee travels along the femur bone to the head of the femur, breaking the posterior wall of the acetabulum. The head of the femur is dislocated outside the joint.T shapeWhen a transverse fracture also had a vertical fracture line, it is called a T shape fracture. Here the innominate bone is broken in such a way that all three parts of it, the ilium, the ischium and the pubis are separated from one another. This is a three part fracture. Though both columns are broken, the weight bearing dome is still attached to the main part of the ilium and hence it is not a true fracture of both columns.

This fracture may be associated with a fracture through the posterior wall as well, making it more complex. This fracture typically occurs when the injuring force is applied from the side, against the greater trochanter of the femur, as in a fall on the side or being hit on the side. This force may be combined with dashboard injury as well. The fracture is best seen in anteroposterior view and iliac and obturator oblique views.

Posterior columnAs with posterior wall injury, this also typically occurs due to dash board injury.Posterior column + Posterior wallThese fractures are extensions of elementary fractures. With the involvement of the posterior wall, the difficulty in treatment increases. These fractures are rarely amenable to non-surgical treatment. Due to posterior wall fracture, the hip is usually dislocated posteriorly, requiring immediate reduction of dislocation and surgical reconstruction after a few days.

The posterior column with posterior wall fracture occurs due to dashboard injury. The anteroposterior view may give clues to these injuries. Judet views and CT scans help in knowing the extent of the injury.

Anterior wallThis fracture is uncommon, typically occurring when the injuring force is applied from the side, against the greater trochanter of the femur bone, as in a fall on the side or being hit on the side.Transverse + posterior wallThese fractures are extension of elementary fractures. With involvement of posterior wall, the difficulty in treatment increases. These fractures are rarely amenable to non-surgical treatment. Due to posterior wall fracture, the hip is usually dislocated posteriorly, requiring immediate reduction of dislocation and surgical reconstruction after few days.

Occurs due to combined dash board injury and direct injury to the hip from the side.

Anterior columnThis fracture is uncommon, typically occurring when the injuring force is applied from the side, against the greater trochanter of the femur bone, as in a fall on the side or being hit on the side. Depending on the location, the fractures are described as very low, low, intermediate and high anterior column fracture.Anterior column + posterior hemi transverseIn this variety of fractures, the posterior or ilio ischial column is broken as a transverse fracture, while the anterior or ilio pubic column is broken into multiple pieces. Part of the weight-bearing dome in this variety of fractures is still attached to that part of the iliac wing, which forms part of the iliac joint. This type of injury has to be differentiated from both column fractures, where the weight-bearing dome is a floating piece not attached directly to the bone-forming sacroiliac joint.

Typically, it is caused by a combination of forces acting on the hip through the femoral head. All three X-ray views plus a CT scan are a must for the diagnosis and management of this complex injury. In this injury, non-operative treatment rarely gives satisfactory results. Surgical management is ideal. The choice of approach rests with the surgeon but going from the front or anterior approach is necessary. The posterior injury may be tacked with the anterior approach by an experienced surgeon. If the patient is unfit to undergo major surgery due to any reason, longitudinal traction to achieve secondary congruence of the hip may help to restore hip function, though partially.

TransverseIn this variety of fracture, the innominate bone is broken such that the upper part consists of ilium with weight bearing dome and the lower part consists of ischium and pubic bones. It typically occurs when the injuring force is applied from the side, against the greater trochanter of the femur bone, as in a fall on the side or being hit on the side. This is a two part fracture, but though both columns are broken, it is not a true both-column fracture, as the weight bearing dome is still attached to main ilium.

In this variety of fracture, the innominate bone is broken such that the upper part consists of ilium with weight bearing dome and the lower part consists of ischium and pubic bones. It typically occurs when the injuring force is applied from the side, against the greater trochanter of the femur bone, as in a fall on the side or being hit on the side. This is a two part fracture, but though both columns are broken, it is not a true both-column fracture, as the weight bearing dome is still attached to main ilium.

Depending on the level at which the fracture line passes in relation to weight bearing area, the transverse fracture is further subdivided into types:

  1. Infra tectal: below the weight bearing dome
  2. Juxta tectal: just at the level of the weight bearing dome
  3. Trans tectal: passing through the weight bearing dome
Diagnosis

X-ray visualization is best done in Antero posterior view and Iliac and obturator oblique views. In CT scan the characteristic feature is that the fracture line runs from front to back. CT scan also helps in identifying impaction of bone pieces and if there are pieces in the joint

Combined both column fracturesThese are the most complex injuries. Here the weight bearing roof or dome of the acetabulum is a floating piece. This adds to complexity of management.
Diagnosis

All three x-ray views plus CT scan is a must for diagnosis and management of this complex injury.

Treatment

Like any other acetabular fracture, if the femoral head is dislocated out of the socket, early reduction into socket is a priority. However, in this injury, non-operative treatment rarely gives satisfactory results. Surgical management is ideal. The choice of approach rests with the surgeon, but going from front, or anterior approach is must. The posterior injury may be tacked with anterior approach by experienced surgeon. If the patient is unfit to undergo major surgery due to any reason, longitudinal traction to achieve secondary congruence of hip may help to restore hip function, though partially.

Presentation

Associated injuries and complications

The broken bone pieces or the dislocated head of the femur may injure the sciatic nerve, causing paralysis of the foot; the patient may or may not recover sensation in the foot, depending on the extent of injury to the nerve. The posterior wall fragment may be one large piece, or multiple pieces, and may be associated with impaction of the bone. Sciatic nerve injury and stoppage of blood supply to the femoral head at the time of accident or during surgery to treat the injury may occur. Deep vein thrombosis and pulmonary embolism are other complications that may occur in any type of injury to the acetabulum. A common postoperative complication is heterotopic ossification around the injured hip joint. [2]

Anatomy

To understand the fracture pattern of a fractured acetabulum, it is essential to have minimum three x-ray views, though use of CT scan with 3-D reconstruction of images has made understanding of these fractures easier.

  1. Pelvis with both hips antero posterior view. This view shows six important landmarks of the acetabulum, specifically:
    • Pelvic brim
    • Ilio ischial line
    • Tear drop
    • Anterior wall
    • Posterior wall
    • Weight bearing dome
  2. Iliac oblique view. This view shows the whole of the ilium, the posterior column, and the anterior wall
  3. Obturator oblique view. Shows the anterior column and the posterior wall.
White: Anterior column, Red: Posterior column Acet anatomy bone model1.jpg
White: Anterior column, Red: Posterior column
Obturator view showing Anterior column and Posterior wall Acet anatomy bone model obturator view3.jpg
Obturator view showing Anterior column and Posterior wall
Iliac oblique view showing Posterior column and Anterior wall Acet anatomy bone model2.jpg
Iliac oblique view showing Posterior column and Anterior wall

Patterns of fracture

Tile's classification of acetabular fracture:

Diagnosis

Ideal x-ray visualization of an elementary fracture will depend on the fracture type:

In all cases, CT scan can assist in identifying impacted bone pieces, which may be found within the joint, and MRI may be done to identify the extent of potential injury to the sciatic nerve.

Treatment

If the femur head is dislocated, it should be reduced as soon as possible, to prevent damage to its blood supply. This is preferably done under anaesthesia, following which, leg is kept pulled by applying traction to prevent joint from dislocating.

The final management depends on the size of the fragment(s), stability and congruence of the joint. In some cases traction for six to eight weeks may be the only treatment required; however, surgical fixation using screw(s) and plate(s) may be required if the injury is more complex. The latter treatment will be called for if bone fragments do not fall into place, or if they are found in the joint, or if the joint itself is unstable.

Post-surgery

Depending on the stability achieved via initial treatment, the patient may be allowed to stand and walk with help of support within about six to eight weeks. Full function may return in about three months.

Principles of management

At the site of injury: After stabilizing an injured person and resuscitation, quick examination is done to check injury to vital organs.

If one suspects injury to the hip, it is imperative to immobilise the limb using some kind of support to prevent movements of the injured limb to prevent further damage

A trained paramedic may be able to diagnose hip dislocation by noticing the position of the injured limb. It is essential to document status of nerves and vessels before starting any treatment to protect oneself from litigation

On arrival at the hospital, trained trauma surgeon will assess the patient and prescribe necessary tests including x-rays as described earlier.

Non-surgical management consists of reducing the dislocated joint by maneuver under anaesthesia and applying traction to the limb to maintain position of joint and fractured bones. If non surgical management is preferred it may require six weeks to 3 months for recovery.

Surgical management

The surgical management requires high degree of training and well equipped centre. It should be carried out by experienced surgical team to get best results. The principles laid down for management are;

  • Anatomic reduction of the fractured fragments
  • Stable fixation
  • Congruent joint
  • Early mobilization
  • Delayed weight bearing

Innominate bone is a flat bone with many curves. In most part the bone is thick enough and has broad surfaces that are amenable to primary fixation using lag screw(s) and to neutralize forces across the bone one needs to add plate(s) on the surface of the fractured fragments for it to heal without deformity.

Before surgery, patient needs tests to check fitness for surgery

Anaesthesia : the surgery may be performed either under regional anaesthesia or general anaesthesia

Surgical approaches. Following are the common approaches;

  • Kocher Langenbeck approach for posterior injuries
  • Ili inguinal, Ilio femoral of modified stoppa's approach for anterior or combined injuries

Implants : normally lag screws and reconstruction plates are preferred implants

Post operative management: would involve initial period or bed rest, followed by mobilisation by trained therapist

Total time to recover may be up to 3 months

Elderly patients have worse outcomes than other populations. Studies show that over 20 percent will require subsequent total hip arthroplasty. [3]

Elementary fractures

Associated fractures

Related Research Articles

<span class="mw-page-title-main">Human leg</span> Lower extremity or limb of the human body (foot, lower leg, thigh and hip)

The leg is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or buttock region. The major bones of the leg are the femur, tibia, and adjacent fibula. The thigh is between the hip and knee, while the calf (rear) and shin (front) are between the knee and foot.

<span class="mw-page-title-main">Femur</span> Thigh bone

The femur, or thigh bone is the only bone in the thigh. The thigh is the region of the lower limb between the hip and the knee. In many four-legged animals the femur is the upper bone of the hindleg.

<span class="mw-page-title-main">Acetabulum</span> Cavity where the thigh bone (femur) articulates with the pelvis

The acetabulum, also called the cotyloid cavity, is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint.

<span class="mw-page-title-main">Bone fracture</span> Physical damage to the continuity of a bone

A bone fracture is a medical condition in which there is a partial or complete break in the continuity of any bone in the body. In more severe cases, the bone may be broken into several fragments, known as a comminuted fracture. A bone fracture may be the result of high force impact or stress, or a minimal trauma injury as a result of certain medical conditions that weaken the bones, such as osteoporosis, osteopenia, bone cancer, or osteogenesis imperfecta, where the fracture is then properly termed a pathologic fracture.

<span class="mw-page-title-main">Hip</span> Anatomical region between the torso and the legs, holding the buttocks and genital region

In vertebrate anatomy, the hip, or coxa in medical terminology, refers to either an anatomical region or a joint on the outer (lateral) side of the pelvis.

<span class="mw-page-title-main">Slipped capital femoral epiphysis</span> Medical condition

Slipped capital femoral epiphysis is a medical term referring to a fracture through the growth plate (physis), which results in slippage of the overlying end of the femur (metaphysis).

<span class="mw-page-title-main">Hip dislocation</span> Orthopedic injury

A hip dislocation is when the thighbone (femur) separates from the hip bone (pelvis). Specifically it is when the ball–shaped head of the femur separates from its cup–shaped socket in the hip bone, known as the acetabulum. The joint of the femur and pelvis is very stable, secured by both bony and soft-tissue constraints. With that, dislocation would require significant force which typically results from significant trauma such as from a motor vehicle collision or from a fall from elevation. Hip dislocations can also occur following a hip replacement or from a developmental abnormality known as hip dysplasia.

<span class="mw-page-title-main">Ischium</span> Lower and back region of the hip bone

The ischium forms the lower and back region of the hip bone.

<span class="mw-page-title-main">Pubis (bone)</span> Most forward-facing of the three main regions making up the os coxa

In vertebrates, the pubis or pubic bone forms the lower and anterior part of each side of the hip bone. The pubis is the most forward-facing of the three bones that make up the hip bone. The left and right pubic bones are each made up of three sections; a superior ramus, an inferior ramus, and a body.

<span class="mw-page-title-main">Obturator artery</span>

The obturator artery is a branch of the internal iliac artery that passes antero-inferiorly on the lateral wall of the pelvis, to the upper part of the obturator foramen, and, escaping from the pelvic cavity through the obturator canal, it divides into an anterior branch and a posterior branch.

<span class="mw-page-title-main">Upper extremity of femur</span>

The upper extremity, proximal extremity or superior epiphysis of the femur is the part of the femur closest to the pelvic bone and the trunk. It contains the following structures:

<span class="mw-page-title-main">Anterior inferior iliac spine</span>

The anterior inferior iliac spine (AIIS) is a bony eminence on the anterior border of the hip bone, or, more precisely, the wing of the ilium.

<span class="mw-page-title-main">Acetabular notch</span> Deep notch in the acetabulum of the hip bone

The acetabular notch is a deep notch in the inferior portion of the rim of the acetabulum. It is bridged by the transverse acetabular ligament, converting it into a foramen. It is continuous with space of the acetabular fossa. The lunate surface of acetabulum is discontinued opposite the notch.

<span class="mw-page-title-main">Iliofemoral ligament</span> Attaches hip to femur

The iliofemoral ligament is a thick and very tough triangular capsular ligament of the hip joint situated anterior to this joint. It attaches superiorly at the inferior portion of the anterior inferior iliac spine and adjacent portion of the margin of the acetabulum; it attaches inferiorly at the intertrochanteric line.

<span class="mw-page-title-main">Acetabular labrum</span> Ring of cartilage that surrounds the acetabulum of the hip

The acetabular labrum is a fibrocartilaginous ring which surrounds the circumference of the acetabulum of the hip, deepening the acetabulum. The labrum is attached onto the bony rim and transverse acetabular ligament. It is triangular in cross-section.

<span class="mw-page-title-main">Femoral neck</span> Aspect of human anatomy

The femoral neck is a flattened pyramidal process of bone, connecting the femoral head with the femoral shaft, and forming with the latter a wide angle opening medialward.

<span class="mw-page-title-main">Outline of human anatomy</span> Overview of and topical guide to human anatomy

The following outline is provided as an overview of and topical guide to human anatomy:

<span class="mw-page-title-main">Hip bone</span> Bone of the pelvis

The hip bone is a large flat bone, constricted in the center and expanded above and below. In some vertebrates it is composed of three parts: the ilium, ischium, and the pubis.

<span class="mw-page-title-main">Pelvis</span> Lower torso of the human body

The pelvis is the lower part of the trunk, between the abdomen and the thighs, together with its embedded skeleton.

X-rays of hip dysplasia are one of the two main methods of medical imaging to diagnose hip dysplasia, the other one being medical ultrasonography. Ultrasound imaging yields better results defining the anatomy until the cartilage is ossified. When the infant is around 3 months old a clear roentgenographic image can be achieved. Unfortunately the time the joint gives a good x-ray image is also the point at which nonsurgical treatment methods cease to give good results.

References

1.Matta JM, Anderson LM, Epstein HC, Hendricks P. Fractures of acetabulum: a retrospective analysis. Clin Orthop 1986; 205:230.
2.Rowe CR, Lowell JD. Prognosis of fractures of acetabulum. J Bone Joint Surg [Am] 1961; 43A: 30 - - 59.
3.Tile M. Fractures of pelvis and acetabulum. Baltimore; Williams & Wilkins. 1984
4.Letournel E. Acetabular fractures, classification and management. Clin Orthop 1980; 151: 81–106.
5.Pennal GF, Davidson J, Garside H, Lewis J. Results of treatment of acetabular fractures. Clin Orthop 1980; 151: 115 - 123.
6.Tile M, Schatzker J. Rationale of operative fracture care. Berlin, Heidelberg, New York; Springer -Verlag. 1987.
  1. ↑ Solomon, APLEY'S TRAUMA AND ORTHOPAEDICS, EIGHTH EDITION
  2. ↑ Stibolt RD Jr, Patel HA, Huntley SR, Lehtonen EJ, Shah AB, Naranje SM. Total hip arthroplasty for posttraumatic osteoarthritis following acetabular fracture: A systematic review of characteristics, outcomes, and complications. Chin J Traumatol. 2018 Jun;21(3):176-181. doi: 10.1016/j.cjtee.2018.02.004. Epub 2018 Apr 26. PMID   29773451; PMCID: PMC6033725.
  3. ↑ Daurka JS, Pastides PS, Lewis A, Rickman M, Bircher MD. Acetabular fractures in patients aged > 55 years: a systematic review of the literature. Bone Joint J. 2014 Feb;96-B(2):157-63. doi: 10.1302/0301-620X.96B2.32979. PMID   24493178.
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