A study presented at the recent 2019 meeting of the American Academy of Orthopaedic Surgeons (AAOS) set out to determine the risks of complications, dislocations, reoperations, revisions and periprosthetic fractures after conversion total hip arthroplasty (THA) as compared with primary or revision THA.
Conversion of Hemiarthroplasty to THA: Risky Business?
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Secondary#periprostheticfractures#hemiarthroplasty#femoralneckfractures
The team of researchers also asked, “How has this effect changed over time?” and “What are the lengths of hospital stay and hospital costs for conversion THA, primary THA, and revision THA?”
Their work, “Conversion of Hemiarthroplasty to THA Carries an Increased Risk of Reoperation Compared With Primary and Revision THA,” has been accepted for publication in Clinical Orthopaedics and Related Research.
Co-author Nick Hernandez, M.D. with the Mayo Clinic in Rochester, New York, explained the genesis of the study to OTW, “There is little information on the complications and costs of conversion THA after hemiarthroplasty for femoral neck fractures.”
“Previous studies have found that they experience higher risk complications, but it has been difficult to quantify the risk because of small sample sizes and a lack of comparison groups. Therefore, we compared the complications of patients undergoing conversion THA with strictly matched patients undergoing primary and revision THA.”
To tease out the answer to those questions, the authors used a longitudinally maintained total joint registry to find 389 patients who had been treated with conversion THA after hemiarthroplasty for femoral neck fractures between 1985 and 2014. They then matched the conversion THA cohort 1:2 on age, sex, and year of surgery to 778 primary THA and 778 revision THA patients.
According to the investigators; “Patients who converted to THA between 1985 and 1999 had a higher risk of complications, dislocations, reoperations, and periprosthetic fractures compared with primary THA. However, conversion THA patients during the 1985 to 1999 time period had a lower risk of reoperations, revisions, and periprosthetic fractures compared with revision THA.”
“The risk differences across the three groups were more pronounced after 2000, particularly when comparing conversion THA patients with revision THA. Conversion THA patients had a higher risk of reoperations and periprosthetic fractures compared with revision THA, but there were no differences in the complication risk, dislocations, and revisions.”
“Length of stay for conversion THA was longer than primary THA (4.7 versus 4.0 days), but there was no difference compared with revision THA (4.7 versus 4.5 days). Similarly, total inpatient costs for conversion THA were higher than primary THA (USD 22,662 versus USD 18,694), but there was no difference compared with revision THA (USD 22,662 versus USD 22,071).”
Dr. Hernandez summarized his study to OTW, “Over the past 30 years, conversion THA after hemiarthroplasty for femoral neck fracture has remained a higher risk procedure in terms of reoperation compared with primary THA, and over time, it also has become higher risk compared with revision THA. Further, the cost of conversion THA is greater than primary THA and similar to revision THA.”
“Surgeons should approach conversion THA after hemiarthroplasty for femoral neck fracture as a challenging procedure, and patients undergoing this procedure should be counseled about the elevated risks. Furthermore, hospitals should seek appropriate reimbursement for these cases.”
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Discussion
This is a fascinating development. In my practice we've seen similar outcomes with the revised protocol. The key differentiator seems to be patient selection criteria. Has anyone else noticed the correlation with BMI thresholds?
Great point. I'd push back slightly on the conclusion, the sample size in the cited study is too small to draw population-level inferences. That said, the directional signal is compelling and worth a larger RCT.
We implemented a similar approach last year. Early results are promising but we're still gathering 12-month follow-up data. Happy to share our protocol if anyone is interested.
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