Dislocation of Hip Joint

Overview

A traumatic hip joint dislocation or hip dislocation occurs when the head of the femur (ball) is pushed out of the acetabular notch (socket). This injury is most commonly a result of a traumatic incident which can be a car collision, a high-impact fall on a straight leg, or contact sports such as gymnastics.  

A dislocated hip joint is often a serious condition and can be extremely debilitating if not treated immediately within hours. Elderly women are more prone to get a dislocated hip joints due to osteoporosis (discussed later). Hip dislocation can also be there congenitally or during the development of the baby. However, in this article, we will focus more on the unwanted, traumatic (injured) type of dislocation of the Hip joint.  

Anatomy

To understand this problem, we will go through a little bit of the anatomy of the hip joint. The hip joint is a ball and socket type joint. The ball is formed by the head (upper end) of the femur; the long thigh bone, while the socket is formed by the acetabular notch or acetabulum; part of the hip bone.  

This ball and socket joint is covered by a smooth layer called articular cartilage, which serves to provide lubrication and to keep the bones in place. Moreover, the acetabular notch is ringed with strong fibrous cartilage called the labarum. The labrum serves to hold the ball in the socket by making a gasket around the edges of the acetabulum. Apart from these support the two bones that are making the joint are tightly held together by several other ligaments e.g., the iliofemoral ligament.  

Types of Dislocations

Hip joint dislocation is often described in two types: 

Posterior Dislocation

This is the most common form and 90% of the cases are of posterior hip dislocation. The thighbone (femur) is pushed out of the socket in a backward direction. A posterior dislocation causes the leg to become fixed in a position, with the knee and foot rotated inwards, i.e., towards the middle of the body. 

Anterior Dislocation

When the ball (femur) is pushed out in a forwards direction i.e., the blow is from the back of the hip joint, the dislocation is termed as an anterior dislocation of the hip joint. In this case, the leg is rotated outwards and away from the midline of the body.  

Different types of hip dislocation via Town Centre Orthopaedics

Symptoms

The blow itself along with damage to the surrounding tissues resulting in severe symptoms which include: 

  • Severe pain  
  • Inability to move leg or thigh 
  • Numbness or tingling – if there is a nerve damage  
  • Swelling – might be caused by injury to a blood vessel 

Causes and Risk Factors

The hip joint like most other joints of the body is a pretty strong joint. A lot of sudden impact or force is required to break away the ligaments and dislocate the hip joint. As mentioned above the most common cause is trauma. Approximately 70% of the cases are caused by motor vehicle collisions. During this collision, the leg hits the dashboard in front which forcefully pushes the leg in a backward direction causing the head of the femur to be pushed out of the socket.  

Another cause that might be associated with hip dislocation is a fall from a high point. Landing on the ground with a straight leg causes forceful expulsion of the ball from the socket resulting in hip dislocation.   

Risk factors may include: 

  • Driving at high speeds 
  • Not using seatbelts  
  • Working in the construction industry – can make you prone to falls  
  • Poor nutrition, especially lack of calcium and vitamin D 
  • Age – young athletes often experience this injury  
  • Sex – post-menopausal females are prone to get a hip joint dislocation  

Diagnosis

A history of sudden trauma with extreme pain and lack of movement can indicate hip dislocation. 

X-ray or CT scans are used to confirm the diagnosis and the extent to which the structures are injured.  

James Heilman, MD, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

Treatment

Treatment therapies include two main procedures: 

  • Reduction procedures – if there are no other associated injuries e.g., fractures or nerve damage, the doctor or orthopaedist will simply give administer an anaesthetic and manipulate the bones back in their positions. This is called reduction.  

Reduction is followed by monitoring with x-rays and CT scans to check if the bones are in their right positions 

  • Surgery – if there are fractures or injury to other tissues like a tear of ligaments or injury to vessels, immediate surgery is required in which the fractures are fixed and bones are put back in their positions 

Complications

In cases where there are associated fractures with dislocation of the hip joint, there can be long-term complications. You might face the following complication: 

  • Nerve injury – as the head of the femur is pushed out of the socket it can compress or injure the nearby nerves. This occurs mostly in posterior dislocations and the nerve at the greatest risk is the sciatic nerve. The sciatic nerve runs from your buttocks down to your knee. Injury to this nerve can cause weakness and even loss of movement in your entire leg. Sciatic nerve injury occurs in 10% of cases of hip dislocation 
  • Osteonecrosis – in case a blood vessel or nerve is torn or cut, the vital supply to the bone, especially the head of the femur can be blocked. This can result in the death of the tissue due to the unavailability of oxygen, nutrients, or lack of nervous stimulation.  
  • Arthritis – pain in the joint due to cartilage damage and increased friction  

Prevention

Hip joint dislocations can be avoided by avoiding traumas i.e., taking precautions to avoid injuries from accidents, falls, or sports. You can: 

  • Wear seatbelts – seatbelts can help you stay in place during the accident and lower the impact between your leg and the dashboard 
  • Drive carefully and under speed limits 
  • Take precaution while working at elevated heights e.g., roofs 
  • Have proper nutrition to avoid bone or cartilage weakening 

Conclusion

Hip dislocation is a serious injury that needs to be treated right away. If you experience a fall or you get into an accident following severe pain or swelling you need to be immediately taken to the hospital or the emergency room.  

The injury is very painful however, with the treatment options available you can get fully treated. The recovery period is long as for most of the musculoskeletal injuries. Most of the time you would need to rest, take pain killers and ask people around you to help you in different task. You can carry on most of your daily life tasks after the prescribed recovery period. 

The content shared in the Health Literacy Hub website is provided for informational purposes only and it is not intended to replace advice, diagnosis, or treatment offered by qualified medical professionals in your State or Country. Readers are encouraged to confirm the information provided with other sources, and to seek the advice of a qualified medical practitioner with any question they may have regarding their health. The Health Literacy Hub is not liable for any direct or indirect consequence arising from the application of the material provided.

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