الفهرس 
Anattomy Off The Hiip JoiinOnly 14 pages are availabe for public view
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Abstract
SUMMARY
Instability either due to recurrent dislocation or aseptic loosening
remains a major complication of total hip arthroplasty (THA). It is the
leading reason for revision THA overall, apart from infection, and is
probably the most common reason for early revision THA.
In revision THA for instsbility factors such as muscular insufficiency,
implant positioning problems or the need for bone reconstruction have been
implicated in postoperative instability. Depending on the reasons for revision,
mean dislocation rates in the literature ranges from 5 to 30%.
Revision strategies typically are directed by the identified causes for
instability. Numerous methods have been described, including reorientation
of the implants, the use of modular implants, elevated rim liners or socket
wall addition, trochanteric advancement, removal of sources of impingement,
and abductor repair. However, even when the etiology could be clearly
identified, failure rates for stability ranging from 20% to 40% have been
reported.
Salvage procedures have been proposed when no obvious etiology
could be identified or when an attempt of stabilization of the hip using one of
the above mentioned methods failed. In such cases, use of an allograft to
increase the static constraints or use of constrained devices have been
reported.
More recently, the use of constraining systems has become the most
popular salvage option. However, success to achieve stability is highly
variable and depends on the constrained component design. Additionally,
such devices raise concerns regarding the potential for increased wear,
osteolysis, loosening, and implant disassembly as reports of failure emerged.