Causes of a Hip dislocation
Roughly nine out of ten hip dislocations occur posteriorly after a large force impacts the bent knee pushing the femoral head out of the hip joint. Forces that causes a posterior hip dislocation commonly involve car accidents with the knee impacting the dashboard. Anterior hip dislocations occur when a large amount of force pulls the leg away from the body while the hip rotates the foot outward such as during a fall. A small number of patients, roughly two percent nationally, dislocate their hips after a total hip replacement in the first year after surgery. Often surgeons can correct these dislocations without the need for additional surgery, but if the internal prosthetic components take on damage the joint will require surgical repair.
Types of Hip Dislocation
Hips can displace towards the front of the body or the back of the body. Anterior, the rarer injury, dislocates towards the front of the body however most dislocations occur posteriorly. When a dislocation occurs, they classify as either a simple or complex dislocation. Simple dislocations occur without an associated fracture and complex dislocations occur with a fracture.
Symptoms of a Hip dislocation
A dislocated hip presents with severe pain, visual deformity and the inability to bear weight. Anterior hip dislocations present with the leg appearing dislocated towards the front of the body. Posterior hip dislocations, much more common, present with the leg deformed towards the back of the body. The differentiation between a simple and complex dislocation requires imaging to determine.
Treating a Hip Dislocation
All hip dislocations require timely treatment within six hours of the injury. Simple hip dislocations often only require a closed reduction, but if dislocation will not reduce to its proper alignment then treatment advances to surgical intervention. Complex dislocations vary depending on what has broken. If small fragments of bone pollute an otherwise stable joint, then surgeons consider an open reduction that involves removing the fragments. Fractures involving destabilization of the acetabulum, femoral head, and femoral neck result in an open reduction and internal fixation, ORIF, surgery to reestablish structural support and set the joint.
Complications from a Hip Dislocation
The risk of developing post traumatic arthritis of the hip affects about twenty percent of patients that suffered from a hip dislocation. This however varies depending on the severity of the dislocation with minor cases having less risk and extensive damage cases having higher chances. Osteonecrosis of the femoral head can occur in up to forty percent of patients, and damage to the sciatic nerve can present in up to twenty percent of cases and correlates with the amount of time the hip spends dislocated. However, while the complications often accompany a hip dislocation the actual risk of a second hip dislocation hovers around only two percent of patients.
Recovery from a Hip dislocation
Recovery from a simple hip dislocation can take months with accompanying regular physical therapy taking place so the soft tissues can heal or stabilize. In cases where the dislocation requires surgical fixation the recovery can take even longer as it involves additional tissue damage such as a broken hip.