Dislocations of the Hip

Dislocations of the Hip

Hip joint dislocations represent a traumatic orthopedic emergency that requires prompt and appropriate treatment. This includes immediate activation of EMS for rapid handling and transport. The common mechanism of injury leading to hip joint dislocations is direct violent trauma. Hip joint dislocations are classified according to their anatomical orientation and are described as anterior, posterior or central. Less common anterior hip joint dislocations are usually the result of substantial force exerted on an abducted leg, levering the anterior part of the femoral head from the acetabulum. A second mechanism of injury that triggers anterior hip dislocation can occur after a strong direct blow to the posterior aspect of the joint. This compromises the anterior ligament structures of the joint and causes the femoral head to protrude from the acetabulum. The most common posterior dislocations are usually the result of significant force transmitted along the shaft of the femur while the knee and hip joints are in a flexed position. The last type of hip joint dislocation, called central, is called the best fracture-dislocation.45 Central hip dislocation usually occurs after applying significant direct force to the lateral aspect of the hip. articulation. This injury mechanism causes the femoral head to be pushed medially towards the acetabulum, resulting in concomitant fractures. The typical biomechanical presentation of the injured lower limb after respective dislocations of the hip joint may be obvious. Upon visual examination of the injured athlete who has suffered an anterior hip dislocation, the lower limb tends to be abducted and externally rotated.

Conversely, after posterior dislocations of the hip joint, the injured lower extremity can present itself in the position of adduction and internal rotation. Due to the complexity of the dislocations of the central hip joint, the affected lower extremity may show a slight shortening, depending on the degree of penetration of the femoral head into the acetabulum.

Common complaints typical of anterior dislocations include considerable pain throughout the hip and the inability to generate joint excursion. Symptoms of paresis can also indicate a pathology associated with the femoral nerve. Paleness and diminished distal pulses should raise suspicions of femoral artery involvement. A specific sign of posterior hip dislocations.

Pain throughout the joint is noticeable, which can sometimes be concentrated in the gluteal region. With posterior displacement of bone fragments, it can result in potential sciatic nerve involvement. This causes referred pain over the entire back of the affected leg. Injury to vascular structures is rare after posterior hip joint dislocations, however this should not dissuade the physical trainer from making a full assessment of these functions of the injured lower limb. The incidence of mortality associated with catastrophic hip joint dislocations is usually the result of accompanying pelvic or thoracic disease. Therefore, thorough assessments of such related injuries are mandatory when managing traumatic hip joint dislocations. Due to the complex nature of hip joint dislocations, attempts at in situ reduction by anyone other than an orthopedic specialist are discouraged. As the incidence of associated pathology increases, the fitness trainer must monitor these injuries, periodically evaluate vital signs and immobilize the hip in the position found pending the arrival of the EMS. Complications of hip joint dislocations include osteoarthritis, Femoral neurovascular involvement specific for anterior dislocation, chronic instability of the hip joint, AVN of the femoral head and sciatic nerve pathology after posterior dislocation. The likelihood of AVN is significantly increased with delayed reduction or repeated unsuccessful attempts to reposition the hip joint dislocation.

.Comparison of Hip Dislocations

■ Anterior hip dislocation: Lower extremity abducted and externally rotated

■ Posterior hip dislocation: Lower extremity adducted and internally rotated

■ Central hip dislocation: Lower extremity may demonstrate a subtle shortening depending on the degree of penetration of the femoral head into the acetabulum Complications of Hip Joint Dislocations

■ Osteoarthritis

■ Femoral neurovascular compromise specific to anterior dislocation

■ Chronic hip joint instability

■ Avascular necrosis of the femoral head

Sciatic nerve pathology subsequent to posterior dislocation

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