[Analysis on morphology and stability of femoral hip prosthesis based on the revision operation].
OBJECTIVE
According to the information obtained from the revision of total hip arthroplasty, the situations of the artificial femoral stem under physiological stress were analyzed preliminarily. In order to accumulate clinical experience, the discussions about how to enlongate the life of artifical joints were performed.


METHODS
Fifty-three patients required revision operations were selected, including 28 males and 25 females,with an average age of 74.66 years old (61 to 84 years old). The average life of artificial joints was 18.24 years (3 to 27 years). The initial weightbearing was started 11 days (5 to 16 days) after the first operation. The main reasons for the revision were the spontaneous loosening and trauma. Based on imaging and surgical findings, as well as the histological pathology, the situations of the stems in human bodies were determined.


RESULTS
Femoral prosthesis would sink under physiological stress. The design of femoral stems, motion of patients', and bone growth determined the secondary stability. Straight stems were helpful for physiological subsidence of prosthesis, achieving the stability with close bone-implant contact by bone growth,which allowed the patient to do early landing exercise. The collared prosthesis and prosthesis combined with internal fixation limited the subsidence of femoral stems. Their stability depends on the time of initial placement and the bone growth for supporting. Delaying the inital weightbearing was suggested for patients with these protheses.


CONCLUSIONS
According to the actual situation of the patients, the appropriate chosen of femoral stems and time to perform the weightbearing can extend the life of the femoral prosthesis.
Zhong-Han
ZH
Min
Hong-Mei
HM
Zhang
Ying
Y
Zhou
Shi-Gui
SG
Yan
Hong-Min
HM
Qin
Xian-Cai
XC
Ye
Zhen-Kang
ZK
Zhu
Jing Lin
Ge-Jun
GJ
Zhao
D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design