Long-term results of 58 hip cup revision arthroplasties using a threaded ring implant.
BACKGROUND
There is still a discussion whether cementless hip cup revisions should be performed with a press fit cup or a threaded ring implant.


METHODS
The results of 58 hip cup changes using the spherical, threaded ring "Munich" are presented. In 16 cases, the ring "Munich I" with a smooth surface and in 42 cases the ring "Munich II" with a corundum-blasted surface were implanted. Mean follow-up was 7.5 years; radiological signs of loosening and the Harris Hip Score were examined.


RESULTS
The re-revision rate for aseptic loosening of the ring was 12/58 overall (Munich I: 5/16, Munich II: 7/42). The average Harris Hip Score was 76.2 overall (Munich I: 74.4, Munich II: 76.8). Higher survival rates were achieved with the "Munich II" ring due to improved construction details.


CONCLUSIONS
These rates are still below those reported for press-fit cups, the technique described by Slooff or reinforcement rings.
von Schulze Pellengahr
Christoph
C
Department of Orthopedics, Grosshadern Medical Center, University of Munich, Marchioninistrasse 15, 81366 Munich, Germany. DrPellengahr@compuserve.de
Düll
Tobias
T
Müller
Peter E
PE
Dürr
Hans Roland
HR
Baur-Melnyk
Andrea
A
Maier
Markus
M
Birkenmaier
Christof
C
Jansson
Volkmar
V
D019644:Arthroplasty, Replacement, Hip; D019544:Equipment Failure Analysis; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D011474:Prosthesis Design; D012086:Reoperation; D016896:Treatment Outcome