Abstract
An audit of a group of dislocations (7 out of 66 hip replacements) revealed a problem with the Charnley Golf Ball cup when used with the posterior approach.
Sixty-six consecutive Charnley hip replacements in one institution by one surgeon using the posterior approach over a one year period are presented. The dislocation rate prior to the introduction of the Golf Ball cup was less than 1%. The overall dislocation rate after the introduction of the Golf Ball socket rose to 10.6%.
Four patients suffered one dislocation, 2 patients suffered two dislocations and 1 patient suffered a dislocation and spontaneous reduction. Five patients were revisions hip replacements and 61 primary hip replacements. Two of the revisions dislocated.
A study of the type of acetabular component type in this series showed there were 17 Wroblewski Angle Bore Sockets (WAB), 11 ogee long posterior wall sockets (OGLPW) and 38 golf ball (GB) sockets making a total of 66 hip replacements.
Of the 17 patients with the WAB the dislocation rate was 0 %. Of the 11 OGLPW patients the dislocation rate was 0 %. However in the 38 patients with golf ball sockets the dislocation rate was 18% (7/38). All the dislocations were anterior.
The acetabular component position was flexion 15–30 degrees (mode 30 degrees) and anteversion 0–10 degrees (mode 0 degrees). The numbers were not large enough to produce any statistical correlation. All femoral stems were set to 0 degrees anteversion.
Following this audit we discontinued the use of the golf ball socket with the posterior approach and have had no further dislocations in primary hip replacement using either the OGLPW or the WAB sockets.
Surgeons who use the posterior approach should be warned about the problems of a high anterior dislocation rate when using the Golf Ball cup.
These abstracts were prepared by Mr Peter Kay. Correspondence should be addressed to him at The Hip Centre, Wrightington Hospital, Appley Bridge, Wigan, Lancashire WN6 9EP.
