Definition/Description[edit | edit source]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. Traumatic hip dislocations is seen as medical emergencies and treatment should be sought as soon as possible.[1] Show
Clinically Relevant Anatomy[edit | edit source]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.[2] 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[edit | edit source]Characteristics[edit | edit source]The following patients characteristics leads to an increased risk of developing a hip dislocation: [3]
Causes[edit | edit source]The causes of hip dislocations can mainly be devided into two groups, mainly congenital and aquired hip dislocations. Congenital hip dislocation (CHD)[edit | edit source]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 for treatment to commence early if
necessary.[5] 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.[6][7]
This is explained by the greater mobility of the hip in women.[3] More than 80% of clinically unstable hips noted at birth have been shown to resolve
spontaneously.[8] Hip dysplasia in an adult Acquired hip dislocation[edit | edit source]Young adults are most affected by traumatic hip dislocations, mostly caused by car accidents and is always the result of an external force with high intensity.[9] Another common mechanism is falling from a height.[5] Hip dislocations are thus rarely isolated, and often goes together with other injuries or fractures. With hip dislocations, the soft tissue around the hip, such as the muscles, ligaments and labrum are also damaged. Neural injuries may also be present.[5] Fractures to the acetabulum and femur head is most commonly associated with traumatic hip dislocations.[9] 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.[10] The position of the hip will be in flexion, adduction and internal rotation, with notable shortening of the leg. With anterior hip dislocations, the hip will be minimally flexed and positioned in abduction and external rotation. A superiorly dislocated hip post trauma
Dislocated total hip replacement Characteristics/Clinical Presentation[edit | edit source]
Differential Diagnosis[edit | edit source]
Diagnostic Procedures[edit | edit source]
Complications[edit | edit source]Immediate:[5]
Long term:[9]
Examination[edit | edit source]
Medical Management[edit | edit source]Conginital dislocation[edit | edit source]Conservative management[edit | edit source]
Surgery[edit | edit source]Surgery is indicated for failed conservative management. Surgery entails release the of the adductor longus muscle, lengthening the psoas tendon, and insertion of a Kirschner wire. This results in marked improvement in hip function and prevents complications later in life.[4] Total hip replacement surgery is an option later in life, when marked functional limitation and pain is present. Acquired hip dislocation[edit | edit source]A dislocated hip should be relocated as soon as possible, as the complication risk of avascular necrosis, neural damage and subsequent dislocations increases with the time between the dislocation and relocation.[9] The Allis maneuver is normally the reduction method of choice for posterior dislocations[9] Non-surgical[edit | edit source]Closed relocation of the hip is done by a traction force performed in the opposite direction of the dislocation, with the hip in 90° flexion. This should preferably be done under general or regional anesthesia and muscle relaxation to prevent greater damage to cartilage and soft tissue.[8] It may also be done in under anaesthetics in theater.[5] After the relocation, the stability of the hip should be tested very carefully. A period of bed rest might be recommended depending on the stability of the hip and the extent of the soft tissue injuries. Surgical[edit | edit source]Indications:
Hip arthroscopy can be used to evaluate intra-articular fractures and chondral injuries and to remove intra-articular fragments, Hip replacement surgery can also be considered if optimal stability is not achieved with relocation and fixation of the associated injuries.[9] Dislocation following hip replacement surgery might indicate revision surgery to ensure the stability of the hip in the long run. Open reduction indications:[9]
Physiotherapy Management[edit | edit source]It is important to take the time frames for soft tissue healing (and bone healing in cases with associated fractures) into consideration with rehabilitation following a hip dislocation. The orthopaedic surgeon will give guidance on weight bearing restrictions that might be present following the medical management of the hip. Full rehabilitation following hip dislocation can take 2-3 months.[5]
See rehabilitation resources below. Resources[edit | edit source]
Clinical Bottom Line[edit | edit source]Hip dislocations are classified into congenial and acquired. Congenital hip dislocations, or developmental hip dysplasia can be successfully managed in children, but might cause problems later in life, when total hip replacement surgery might be indicated to improve function, leg length discrepancies and pain. Acquired, or traumatic hip dislocations are medical emergencies, and treatment should be sought as soon as possible. Relocation should ideally occur within 6 hours from the dislocation, in order to reduce complications. Traumatic dislocations are reduced either open or closed, and open or arthroscopy surgery might be indicated in cases with associated fractures. Physiotherapy plays an important role in the rehabilitation following a hip dislocation, in order to get the patients back to their previous level of function, and to prevent further dislocations. References[edit | edit source]
What is acetabular dysplasia in the hips?What is acetabular dysplasia? Acetabular dysplasia is an abnormally shallow hip socket that leads to uncovering of the femoral head and excessive pressure on the rim of the hip socket. This can be painful — especially if you are active.
How could a shallow acetabulum cause issues for a patient?Acetabular dysplasia, or hip dysplasia, is a disorder that occurs when the acetabulum (hip socket) is shallow and doesn't provide sufficient coverage of the femoral head (ball), causing instability of the hip joint.
Is it normal for the femoral head to be seated within the acetabulum?The normal hip (see figure) is a ball and socket joint with the femoral head (ball) well-seated and stable within the acetabulum (socket).
What is the head of the femur?The femoral head is the most proximal portion of the femur and is supported by the femoral neck. It articulates with the acetabulum of the pelvis. The femoral head is nearly spherical (two-thirds) but has a medial depression known as the fovea capitis femoris that serves as an attachment point for the ligamentum teres.
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