Hip Dislocation

Original Editor - Annelies Noppe

Top Contributors - Annelies Noppe, Leana Louw, Lucinda hampton, Kim Jackson, Lokiru Paul, WikiSysop, Vidya Acharya, Anas Mohamed and Kirenga Bamurange Liliane

Definition/Description

Hip dislocation is the displacement of the femur head from the acetabulum. Most of the times this causes damage at the tissue around the hip.

Clinically Relevant Anatomy

The ball-and-socket joint of the hip anatomy exist of the acetabulum and the femur head. The acetabulum has the shape of a cup and the femur head the shape of a ball.

The hip is a weight bearing ball joint mainly functioning as support. The stability of the hip joint is provided mainly by the capsule and the surrounding muscles and ligaments. They stabilise the femur head in the acetabulum and ensure that the hip joint are able to move in all available planes.

Epidemiology /Etiology

Characteristics

The following patients characteristics leads to an increased risk of developing a hip dislocation:

• Female > male
• Alcohol abuse
• Various pre-operative disorders
• Older age:
  • Decreased muscle mass reduces the stress on the hip prosthesis and decreases the natural protection against hip dislocation
  • Increased risk of falling due to compromised balance
  • Neuromuscular dysfunction associated with old age - e.g. neuropathy or cerebrovascular accident
  • Cognitive impairments
• Great dexterity
• Poor follow instructions
• Increased tendency to fall

Causes

The causes of hip dislocations can mainly be devided into two groups, mainly congenital and aquired hip dislocations.

Congenital hip dislocation (CHD)

Also known as developmental dysplasia of the hip (DDH). All newborn babies have their hips assessed for DDH within a few days of birth and at six weeks in order fr treatment to commence early if necessary. CHD occurs with an incidence that vary between 1.5 and 20 per 1.000 births and is 8 times more commonly in girls than in boys. This is explained by the greater mobility of the hip in women.

Acquired hip dislocation

Traumatic dislocation of the hip are mostly caused by car accidents and is always the result of an external force with high intensity. Hip dislocations are thus rarely isolated, and often goes together with other injuries or fractures. Hip dislocations are classified as either anterior or posterior, depending on the displacement of the femur head in relation to the acetabulum. Posterior hip dislocations are more common, and makes about 85-90% of the cases. The position of the hip will be in flexion, adduction and internal rotation. With anterior hip dislocations, the hip will be minimally flexed and positioned in abduction and external rotation.

Dislocation after hip replacement surgery has the highest incidence rate immediately after the surgery or in the first three months. The incidence of hip dislocation following hip replacement surgery depends on patient, surgical and hip implant factors. In general, the larger the head of the femur post surgery, the less likely a patient is to experience dislocation.

Characteristics/Clinical Presentation

• Pain:
  • Severe pain is the most common symptom. With the separation of the femur head from the acetabulum, surrounding muscles and tendons can be damaged as well. Subsequent knee injuries might also be present.

• Swelling

• Leg length discrepancy and deformity:
  • In most of the cases is the affected leg will appear shortened and the hip joint deformed

• Hip immobility:
  • Difficulty moving the affected hip
  • Inability to walk as a result of pain and swelling

Differential Diagnosis

Hip luxation occurs from a lower-energy forward fall on the flexed knee and hip. These patients present with painful and limited ROM.⁷ But these symptoms are not only the symptoms of a hip luxation but also of a hip dysplasia.⁹ The term hip dysplasia means an abnormality of shape or size of the acetabulum or femoral head, or of their proportions or alignment one to the other. ¹³ There is still a difference, in the case of a luxation, the patient isn’t able to walk and a patient with a hip dysplasia can still walk but he has muscle pain in his upper leg. ⁹ In both cases there can be radiating pain to the knee and the range of motion will be reduced. Actually, in the most cases, a hip luxation is a result of a hip dysplasia. Patients with more chronic hip instability may be able to voluntarily sublux or dislocate their hip.⁷ Because when the femoral head or the acetabulum is abnormal, the femoral head can easy go out of the cup and in that case you have a luxation of the hip. When they think about a luxation of the hip, they must take a x-ray photo for the security. The x-ray photo is also necessary for to know sure that the luxation doesn’t have a fracture also. When they definitely want to know that there is nothing wrong with the spine, a CT-scan is an option.¹²

Medical Management

In the recognition and treatment of patients with hip dislocation, the following points are important:

Radiographic examination before and after you put the hip in the right place to determine the type of dislocation and potential fractures.
There should be a radiographic examination of the pelvis with patients who have a severe injury at their thigh (fracture of the femur).
A dislocated hip should be placed in position as soon as possible. Otherwise, the risk of Avascular necrosis, nerve damage, and second luxation increases.
Repositioning of the hip without surgery is done by a traction performed in the opposite direction of the dislocation, with 90° flexion in the hip. This should preferably be done under general or regional anesthesia and muscle relaxation; this to prevent greater damage to cartilage and soft tissue⁵.
After the repositioning, the stability of the hip should be tested very carefully.
If the repositioning fails, with instability or there are fractures of acetabulum or femoral head, operation must take place.
In surgery, the joint must be cleaned of any loose bone fragments or soft tissue that would prevent proper articulation. The purpose of the operation is to let the femoral head make the same movements like before. They have to take attention for the emergence of a osteonecrosis from the femoral head.¹¹

Hip arthroscopy can be used to remove intra-articular fragments, evaluate intra-articular fractures and chondral injuries.

Physiotherapy Management

More than 80% of clinically unstable hips noted at birth have been shown to resolve spontaneously⁵. In newborn babies, flexion / abduction maneuvers can be sufficient. Another way to treat DDH is to holding the hip flexed and abducted (with the leg pulled up and turned out) for one or two months by the use of a brace, splint or harness. This keeps the top of the femur in the right position while the ligaments and bones grow and strengthen around it. If all this fails, surgical management is indicated. A study ⁷ suggests that the surgeon release the adductor longus, lengthen the psoas tendon, and insert a Kirschner wire. This simple and safe surgical procedure results in marked improvement in hip function and prevents complications later.

Traction treatment is very common and important part of the therapy treatment.
Hip flexion can help increase strength and muscular support in the hip. Hip flexion can help increase strength and muscular support in the hip. We do hip flexion passive ! Hip extension is a very good way to work on the range of motion of the hip, especially for person with a Hip dysplasia.
If a person has a luxation of the hip, there is always also a hip dysplasia. If you have a hip dysplasia however, it is not always the case that you have a luxation.
Stretching and joint mobilization is a notable way necessary for the rehabilitation. Step by step the patients learn to use the hip to its full extent.

Resources

Articles
²Patel H. Canadian Task Force on Preventive Health C. Preventive health care, 2001 update : screening and management of developmental dysplasia of the hip in newborns. Can Med Assoc 2001; 164(12): 1669-1677(3A , Grades of recommendation : D)
⁶ Barlow T. Congenital Dislocation of the Hip. J. Bone Joint Surg. 1962;44:292-301 (3B)
⁷ J. Pediatr. Ortop. B. 2012 Nov. Traumatic Hip Dislocation In Children; 21(6):542-51 (2B)
⁸ Navarro-Zarza JE. Clinical anatomy of the pelvis and hip. Reumatol Clin. 2012 Dec.(3B)
⁹ Lisa M. Tibor, Differential Diagnosis of Pain Around the Hip Joint, Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 24, No 12 (December), 2008: pp 1407-142.1 (5)
¹⁰Mw.M.van der Grinten, prof.dr.J.A.N.Verhaar, orthopedisch chirurg. Luxatie van totale heupprothese risicofactoren en behandeling (2B)

¹³ K. Klaue, C. W. Durnin, R. Ganz, The acetabular rim syndrome – a clinical presentation of dysplasia of the hip, may 1991 (5)

Sites
³ http://www.ntvg.nl/publicatie/luxatie-van-totaleheupprothese-risicofactoren-en-behandeling/volledig/print
⁵ http://emidicine.medshape.com/article/86930-treatment
¹⁴ http://orthoinfo.aaos.org/topic.cfm?topic=a00347

Books
¹ Orthopedic Radiology by Adam Greenspan, J.B. Lippincott 1988.
⁴ DeLee JC. Fractures and Dislocations of the Hip. In: Rockwood CA Jr, Green DP, Bucholz R (eds): Fractures in Adults. Vol 2. 4th ed. Philadelphia: Lippincott-Raven, 1996, pp. 1756-1803.
¹¹ ‘De grote medische encyclopedie’, publishing Heideland, Hasselt, botten en gewrichten, spieren en huid
¹² ‘Gezin en gezondheid’, publishing Cambium B.V. , Zeewolde, 1995, David E. Larson, M.D, translated by Prof. DR J.W. Van Ree and Prof. Em. DR R. De Smet

Visual
http://www.rightdiagnosis.com/animations/hip-dysplasia-pediatric.htm