الفهرس 
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Abstract
Total hip arthroplasty is the most commonly performed adult
reconstructive hip procedure. Total hip arthroplasty evolved as a result of
many improvements of designs of femoral head prosthesis, the
availability of suitable component materials and manufacturing
techniques, a better understanding of hip biomechanics, and the need for
resurfacing the acetabulum.
Total hip arthroplasty has been associated with excellent implant
survival rates, but debate remains concerning the best fixation method for
the components. Many studies were done to compare the results of
fixation with and without cement and to compare between alternative
bearing surfaces.
Commonly, cemented hip replacements provide an excellent
primary fixation by giving an initial “custom fit” and resistance to axial
and torsional stresses, thus allowing early pain-free function. The
disadvantages, however, may be considerable in active people; indeed
long-term cement fatigue, due to the application of repeated loads during
daily activity can drive the stem to failure. Furthermore, in case of failure,
the cement may be difficult to remove.
Despite being in clinical use for many years, the success of
cemented femoral stems is still not completely understood. Many reports
have demonstrated good long term results with cemented stems.
Therefore it seems justified to still use cemented stems in all age groups
of patients. Otherwise, cementless stems have good outcomes in longterm
follow-up due to their stable secondary fixation, but they could
produce problems in osteoporotic and heavy patients.
Summary (decision making)
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Furthermore, the poor bone quality in addition to sever and
continuous loads can lead to early stress shielding and a higher incidence
of thigh pain, as well as a decrease in function.
Uncemented total hip prostheses are used predominantly in
younger patients. In recent years implant design changes have been made
to achieve more proximal load transfer into the femur to reduce proximal
stress shielding and thus preserve bone stock for potential revision
surgery. The short and midterm results for these prostheses are promising.
In conclusion, the published evidence suggests that cement
fixation remains excellent and even superior to cementless fixation for the
general population with respect to femoral stem fixation. The results of
cemented cups have been inferior to cementless fixation in most
published reports. Cementless fixation in THA, however, has
demonstrated continued improvement in durability. Further research and
refinement of study & signs are necessary to more accurately demonstrate
the relative value of cement or fixation in THA performed in specific
subgroups of patients.
THA has been well established in long-term studies in older
patients as a reliable, reproducible, and durable treatment option for hip
arthritis. However, studies in younger patients have traditionally shown
less promising results. The higher failure rate of THA in young patients
has been attributed to high activity level and excessive demands on the
prosthetic hip, along with traditional techniques and cemented
components.