Total Hip Arthroplasty After Acetabular Fracture Is Associated With Lower Survivorship and More Complications.
BACKGROUND
Despite modern fracture management techniques allowing for near anatomic reduction of acetabular fractures, there continues to be a risk of posttraumatic arthritis and need for total hip arthroplasty (THA). Few well-controlled studies have compared THA after acetabular fractures with THAs performed for other indications in terms of survivorship or complications, and none, to our knowledge, present 10-year survivorship data in this setting.


OBJECTIVE
(1) How does the 10-year survival of THA compare between those patients who underwent THA after an acetabular fracture and those who underwent THA for primary arthritis or avascular necrosis (AVN)? (2) Is there an increased risk of serious complications like infection, dislocation, and aseptic loosening as well as heterotopic ossification associated with a THA performed after a previous acetabular fracture?


METHODS
This retrospective case-control study compared findings of patients who underwent THA after acetabular fracture versus a matched cohort of patients who had received a primary THA for primary osteoarthritis or AVN. Between 1987 and 2011, we performed 95 THAs after acetabular fracture; of those, 74 (78%) met inclusion criteria and had documented followup beyond 2 years in our institutional registry. We selected 74 matched patients based on an algorithm that matched patients based on preoperative diagnosis, date of operation, age, gender, and type of prosthesis. During this time, we performed approximately 8000 THAs that were potentially available for matching based on complete followup beyond 2 years. We compared cases and control subjects using the Kaplan-Meier survivorship estimator as well as a comparison of the proportions in each group that developed major complications (including infection, dislocation, loosening, and heterotopic ossification) based a retrospective chart review.


RESULTS
The 10-year survivorship after THA was lower in patients with a previous acetabular fracture than in the matched cohort (70%, 95% confidence interval [CI], 64%-78%, versus 90%, 95% CI, 86-95%; p < 0.001). There was no difference in the 10-year survival rate for those patients whose acetabular fracture was initially treated conservatively and those treated by open reduction and internal fixation. Patients with previous acetabular fracture had a higher likelihood of developing infection (7% [five of 74] versus 0% [zero of 74]; odds ratio [OR], 11.79; p = 0.028), dislocation (11% [eight of 74] versus 3% [two of 74]; OR, 4.36; p = 0.048), or heterotopic ossification (43% [32 of 74] versus 16% [12 of 74]; OR, 3.93; p < 0.001).


CONCLUSIONS
In this case-control study, patients with a prior acetabular fracture had markedly inferior 10-year survivorship and more frequent serious complications when compared with patients undergoing THA for primary osteoarthritis or AVN. Given these findings, management of these complex cases should be in highly specialized units where the expertise of arthroplasty and trauma reconstruction is available.


METHODS
Level III, therapeutic study.
Li Ka Shing Institute, St Michael's Hospital, University of Toronto, West Basement B-114, 209 Victoria Street, Toronto, ON, M5B 1W8, Canada. morisonz@smh.ca.
Zachary
Z
Morison
Department of Orthopaedics and Traumatology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
Dirk Jan F
DJ
Moojen
Division of Orthopaedic Surgery, Department of Surgery, St Michael's Hospital, Toronto, ON, Canada.
Aaron
A
Nauth
Division of Orthopaedic Surgery, Department of Surgery, St Michael's Hospital, Toronto, ON, Canada.
Jeremy
J
Hall
Division of Orthopaedic Surgery, Department of Surgery, St Michael's Hospital, Toronto, ON, Canada.
Michael D
MD
McKee
Division of Orthopaedic Surgery, Department of Surgery, St Michael's Hospital, Toronto, ON, Canada.
James P
JP
Waddell
Division of Orthopaedic Surgery, Department of Surgery, St Michael's Hospital, Toronto, ON, Canada.
Emil H
EH
Schemitsch
D000077:Acetabulum / Q000293:injuries / Q000503:physiopathology / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D005260:Female; D050723:Fractures, Bone / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D006617:Hip Dislocation / Q000209:etiology; D006621:Hip Joint / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D009999:Ossification, Heterotopic / Q000209:etiology; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome