Hip Dislocation

Original Editor - Annelies Noppe

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

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
• Chronic hip instability

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.
  • Radiating knee pain

• 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:
  • Reduced hip range of motion
  • Inability to walk as a result of pain and swelling

Differential Diagnosis

• Hip dysplasia
• Hip sublaxation

Diagnostic Procedures

• X-rays: AP pelvis and lateral
  • To confirm dislocation or successful relocation
  • Assess for associated fractures
• CT:
  • To rule out concomitant injuries in traumatic dislocations (e.g. acetabulum or femur head fractures)
  • Clearance of lumbar spine

Medical Management

A dislocated hip should be relocated as soon as possible, as the complication risk of avascular necrosis, neural damage and subsequent dislocations increases with time.
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