A new method of socket wear measurement in Charnley total hip replacement.
A new technique of wear measurement of the Charnley type socket is developed and introduced with an evaluation of its advantages and reliability. The principle in this technique is as follows: the X-ray projection angle of the radiograph taken before wear is corrected by some calculations on the basis of the second radiograph taken after wear has occurred. Then, on the identical X-Y coordinate axes made on these films, the shift of the femoral head's center (that is the wear vector) reveals the amount and direction of socket wear. When experimental wear of a socket was measured with this technique, the amount of wear was found accurate independent of varying socket fixating angle or irradiating direction. This technique has certain problems including technical complexity and the need for a new radiograph. However, it is useful clinically, because two-dimensional evaluation of socket wear both in amount and direction is possible.
Tsurumoto
T
T
Department of Orthopaedic Surgery, Nagasaki University, School of Medicine, Japan.
Iwasaki
K
K
D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans