Radiographic evaluation of the Zurich cementless total hip acetabular component.
OBJECTIVE
To radiographically evaluate the Zurich cementless total hip (ZCTH) cup and correlate lucency with clinical signs of implant instability, time since surgery, and implant generation, using zonal analysis.


METHODS
Retrospective study.


METHODS
Client-owned dogs (n = 53).


METHODS
Radiographs of dogs that had ZCTH arthroplasty (>1 year) were evaluated using zonal analysis, for lucency surrounding the cup-bone interface (number of zones, length, area). Dogs were examined for clinical signs of implant instability (lameness, hip pain). Lucency was correlated with lameness, time after surgery, and implant generation.


RESULTS
Radiographs of 68 implants (18 generation I, 50 generation II) were evaluated. Eight dogs were lame (11.8%). Dogs with lameness were more likely to have lucency in > or =2 zones of analysis (per view), have >2 times the average curvilinear length of lucency, and have >4 times the average area of lucency surrounding the implant compared with non-lame dogs. A weak relationship was observed between time after surgery and implant generation; however, there was no relationship between time after surgery and lucency.


CONCLUSIONS
Dogs with lameness after ZCTH arthroplasty were more likely to have lucency at the cup-bone interface. Lucency was better evaluated by radiographic projection than zonal analysis. Temporal progression of lucency was weakly correlated with implant generation.


CONCLUSIONS
Dogs with lucency in > or =2 zones of analysis should be evaluated more frequently for clinical signs of implant loosening. Further investigation of serial radiographs after ZCTH arthroplasty is warranted.
Hanson
Steven P
SP
Affiliated Veterinary Specialists PA and Central Florida Veterinary Radiology PA, Maitland, 32751, USA.
Peck
Jeffrey N
JN
Berry
Clifford R
CR
Graham
John
J
Stevens
Gary
G
D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000818:Animals; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D001843:Bone Cements; D004283:Dog Diseases / Q000000981:diagnostic imaging / Q000601:surgery*; D004285:Dogs; D005260:Female; D006619:Hip Dysplasia, Canine / Q000000981:diagnostic imaging / Q000601:surgery*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery; D006622:Hip Prosthesis / Q000662:veterinary*; D007593:Joint Instability / Q000662:veterinary; D007794:Lameness, Animal / Q000209:etiology; D008297:Male; D011475:Prosthesis Failure / Q000662:veterinary*; D011859:Radiography; D012189:Retrospective Studies; D016896:Treatment Outcome
D001843:Bone Cements