Fate of the unrevised cemented stem following cup only revision: 227 hips at an average of 6 years follow-up.
BACKGROUND
After primary total hip replacement, aseptic loosening of the acetabular cup is more common than loosening of the femoral stem. Removal of a well-fixed stem adds to operative time, blood loss, risk of bone loss and fracture. There is limited evidence that isolated cup revision can be a safe option in revision hip arthroplasty. We question the following regarding the unrevised cemented stem after isolated cup revision: 1) Does the unrevised stem require revision after isolated cup revision? 2) When is the stem subsequently revised? 3) Why is the stem subsequently revised? 4) Do unrevised stems exhibit radiographic loosening?


OBJECTIVE
We hypothesise that after isolated cup revision most unrevised stems do not need subsequent revision, and that most do not exhibit evidence of radiographic loosening.


METHODS
A retrospective analysis of all patients who underwent revision of the acetabular component only during revision hip arthroplasty between March 1970 and July 2013 was carried out. We assessed survival of the unrevised stem, reasons for subsequent revision, plus radiographic analysis for stem loosening.


RESULTS
Two hundred and twenty-seven hips were included [215 patients with an average age at the time of primary surgery was 47 (13-70) years]. The Charnley stem was used in 161 cases; C-stem 65, Howse 1. Average time between primary surgery and cup revision was 15.9 (1.6-33.4) years. Average follow-up for all stems post-isolated cup revision was 6.1 (0.1-30.7) years. Twenty-eight stems (12.3%) were subsequently revised 5.1 (0.1-12.6) years after the isolated cup revision. Reasons for subsequent revision were: aseptic loosening (10); infection (8); dislocation (6); unreconstructable joint post-loose cup removal (2); fracture (2). Radiographic review was possible on 140 cases. Five femoral stems were revised and 2 others showed evidence of possible radiological loosening but were not revised.


CONCLUSIONS
To our knowledge this is the largest series showing that isolated cup revision in the place of a well-fixed cemented stem is safe and is associated with ongoing good long-term survival of the stem.


METHODS
Level IV, retrospective case series.
Wrightington Hospital, Hall Lane, Appley Bridge, Wigan, Lancashire, WN6 9EP, United Kingdom. Electronic address: lorcanmcgonagle@hotmail.com.
L
L
McGonagle
Wrightington Hospital, Hall Lane, Appley Bridge, Wigan, Lancashire, WN6 9EP, United Kingdom.
P D
PD
Siney
Wrightington Hospital, Hall Lane, Appley Bridge, Wigan, Lancashire, WN6 9EP, United Kingdom.
V V
VV
Raut
D000293:Adolescent; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D001843:Bone Cements; D005260:Female; D005500:Follow-Up Studies; D006615:Hip; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D057068:Periprosthetic Fractures / Q000601:surgery; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000601:surgery; D012086:Reoperation; D012189:Retrospective Studies; D055815:Young Adult
D001843:Bone Cements
Cup; Isolated; Stem; THR revision; Unrevised