page_title: Hip replacement
section_title: Dislocation
hierarchical_section_title: Hip replacement / Risks / Dislocation
caption_attribution_description: English: A dislocated hip prosthesis.
context_page_description: Hip replacement is a surgical procedure in which the hip joint is replaced by a prosthetic implant, that is, a hip prosthesis. Hip replacement surgery can be performed as a total replacement or a hemi replacement. Such joint replacement orthopaedic surgery is generally conducted to relieve arthritis pain or in some hip fractures. A total hip replacement consists of replacing both the acetabulum and the femoral head while hemiarthroplasty generally only replaces the femoral head. Hip replacement is currently one of the most common orthopaedic operations, though patient satisfaction short- and long-term varies widely. Approximately 58% of total hip replacements are estimated to last 25 years. The average cost of a total hip replacement in 2012 was $40,364 in the United States, and about $7,700 to $12,000 in most European countries.
context_section_description: Dislocation is the most common complication of hip replacement surgery. The most common causes vary by the duration since the surgery.
  Hip prosthesis dislocation mostly occurs in the first three months after insertion, mainly because of incomplete scar formation and relaxed soft tissues. It takes eight to twelve weeks for the soft tissues injured or cut during surgery to heal. During this period, the hip ball can come out of the socket. The chance of this is diminished if less tissue is cut, if the tissue cut is repaired and if large diameter head balls are used.
  Dislocations occurring between three months and five years after insertion usually occur due to malposition of the components, or dysfunction of nearby muscles.
  Risk factors of late dislocation (after five years) mainly include:
  Female gender
  Younger age at primary hip arthroplasty
  Previous subluxation without complete dislocation
  Previous trauma
  Substantial weight loss
  Recent onset or progression of dementia or a neurological disorder
  Malposition of the cup
  Wear of the liner, particularly when it causes movement of the head of more than 2 mm within the cup compared to its original position
  Prosthesis loosening with migration
  Surgeons who perform more of the operations each year tend to have fewer patients dislocate. Doing the surgery from an anterior approach seems to lower dislocation rates when small diameter heads are used, but the benefit has not been shown when compared to modern posterior incisions with the use of larger diameter heads. The use of larger diameter head size does in itself decrease the risk of dislocation, even though this correlation is only found in head sizes up to 28 mm, thereafter no additional decrease in dislocation rate is found. People can decrease the risk further by keeping the leg out of certain positions during the first few months after surgery.
caption: Dislocated artificial hip
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