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Hip Arthroplasty: Management Problems
Hip dislocation complicating primary total hip replacement is unusual. Fortunately, if it occurs, 60% of patients will have only one dislocation.1 Postoperative hip dislocation usually can be prevented. For that reason, it is important to know the predisposing cause and minimize the risk. Therefore, it is useful to consider the causes and cures of hip dislocation complicating primary total hip replacement from a surgical, implant, and patient standpoint.
SURGICAL CONSIDERATIONS
While there are numerous advantages to each of the traditional surgical approaches to the hip (anterolateral, direct lateral, or posterior approach), it is clear that the posterior approach is associated with the highest risk for postoperative dislocation. While there are many other advantages to using the posterior approach, it is important to bear Ulis in mind. During surgery, it is important to ensure that impingement of die implant is eliminated throughout the arc of motion. To this end, it is equally important to ensure that the components are oriented appropriately with adequate anteversion of both the femoral and acetabular components having been achieved.
The concept of "balancing" a primary total hip replacement needs to be reinforced. While most orthopedic surgeons are conversant with the concept of balancing a total knee replacement, balancing of a total hip replacement is not always well taught and is sometfiing that is perhaps not done with as much frequency as it should be. With the trial components in place, the surgeon should ask himself two questions: Is the position of the primary total hip stable? Is it balanced?
If the hip is stable, it will be stable in flexion and adduction as well as during internal rotation. It also will be stable with axial traction applied in 15° of flexion with the hip and knee in the extended position. Many patients with osteoarthritis of the hip have a fixed external rotation contracture of their hip preoperatively. It is important therefore to ensure that this contracture is corrected at the time of primary total hip replacement and that the external rotators as well as the hip flexors are not too tight. If, after inserting the trial components, the hip still has an external rotation contracture, it is important to release obturator externus to ensure that...