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Excellent survivorship with cementless acetabular component at 15 years
Very low re-revision rates reported.
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Patients who underwent revision total hip arthroplasty with cementless acetabular components had low rates of loosening and re-revision after 15 to 19 years, said a U.S. researcher.
This study is among the first to examine long-term results of revision hip arthroplasty with cementless components.
“In North America, cementless acetabular reconstruction has become the standard for revision total hip arthroplasty. ... It is a very familiar and straightforward surgical technique, and it is applicable to the majority of acetabular defects encountered. However, there are few studies that document the results of cementless acetabular revisions at more than 10 years,” said Craig Della Valle, MD, of Rush University Medical Center in Chicago.
Della Valle noted that complications with these components such as osteolysis, wear and late loosening increase after 10 years for primary hip replacements.
This study looked at 138 consecutive revision total hips, with an average age of 55 years that Della Valle said was “on the young side.” Most of the included hips received a two-component revision, but 13% were isolated acetabular revisions.
Line-to-line reaming
All patients received the HG-1 acetabular component (Zimmer). The surgical technique included “line-to-line reaming of the acetabulum with the insertion of three to six screws,” Della Valle said at the American Academy of Orthopaedic Surgeons 72nd Annual Meeting. Surgeons used components with a median size of 62 mm, and bone graft in many cases.
After a minimum of 15 years, 41 patients had died, representing 43 hips. Another seven were lost to follow-up, and surgeons revised 20 patients. The remainder included 67 hips in 64 patients.
Surgeons performed final clinical follow-up at an average of 205 months, with final radiographic evaluation at 206 months. They used the Harris hip score for clinical evaluation, and looked specifically at osteolysis and used the Paprosky classification to analyze bone deficiency. Most patients had type 2 acetabular defects, Della Valle said. To determine risk factors for failure, researchers also performed Kaplan-Meier survivorship and other statistical analyses.
They cited instability as among the main causes of failure leading to seven revisions among the 20 revised hips, while infection caused another six revisions. Nineteen of these 20 acetabular shells were found well fixed at the time of revision surgery.
Harris hip scores improved from 49 to 82 (P<.001), with about two-thirds of the hips scoring in good to excellent range. Researchers found two radiographically loose cups; one of these patients died without requiring a revision, and the other remains asymptomatic and is low demand.
“Osteolysis was the biggest change when we looked at this cohort, with 40% of patients showing some evidence of osteolysis,” Della Valle said.
Researchers found excellent survivorship results: 97% for radiographic loosening or revision due to loosening at 15 years. For acetabular revision (for any reason), survivorship dropped to 81% at 15 years. Survivorship free of osteolysis dropped further to 70%.
Dr. Della Valle is a paid consultant to Zimmer Inc.
For more information:
- Della Valle C, Shuaipaj T, Berger RA, et al. Revision total hip arthroplasty with a cementless acetabular component: evaluation at 15 to 19 years. #273. Presented at the American Academy of Orthopaedic Surgeons 72nd Annual Meeting. Feb. 23-27, 2005. Washington.