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Orthopaedic

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Arthritis

Question
99 out of 101
 

Which of the following statement(s) is/are correct concerning total joint replacement arthroplasty?



A Total knee and hip prostheses have a life expectancy of approximately 10 years

B The major failure of total joint arthroplasty is aseptic mechanical loosening at the interface between the bone, cement, and implant

C Biologic tissue ingrowth into a prosthesis worsens long-term results

D Rigid fixation at the time of implantation is important to secure tissue ingrowth

Ans. B
The major failure of total joint arthroplasty is aseptic mechanical loosening at the interface between the bone, cement, and implant

D. Rigid fixation at the time of implantation is important to secure tissue ingrowth

a. Significant technological advances in both the biomaterial and manufacturing process have lead to dramatic improvement in total joint replacement surgery during the last 20 years.

b. These advances have significantly improved the longevity of artificial joints, particularly hip and knee prostheses, which are by far the most common. Despite these advances the procedure is still considered primarily for elderly patients.

c. Total knee and hip prostheses have a fixation life expectancy of about 15 years or more in many patients. The major failure of total joint arthroplasty is aseptic mechanical loosening at the interface between the bone, cement, and implant.

d. Factors which contribute to loosening include excessive weight, high activity level, component misalignment, and breakdown of the cement interface.

e. An important potential advance, and one that has demonstrated some clinical success already, is the use of porous surface coated prostheses that promotes biological tissue ingrowth and fixation of the implants.

f. These implants are designed to be inserted surgically into carefully prepared bone under conditions of interference fit (tight intimate contact).

g. It is proposed that significant bone tissue infiltration into the porous surface will begin within 8 to 12 weeks and that after an appropriate amount of time (perhaps 1 year) long-term equilibrium bone remodeling will result in a well-fixed bone ingrowth phase that will last for years.

h. Two factors are important to secure fixation. First, the implant must be fixed rigidly within the bone during the initial ingrowth period. Secondly, the local mechanical environment must promote a positive remodeling response of the supporting trabecular bone.

Arthritis Flashcard List

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