When it comes to demanding hip revision surgeries, mused a team from New York University (NYU) Langone Health, what would using an isolated head and liner exchange mean for instability outcomes and follow-on revisions?
One Factor Can Increase Re-Revision THA Risk 7-Fold!
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Secondary#hipsurgery#isolatedheadandlineareschangemean#postoperativeinstability
In addition, what is the association between patient-specific factors, surgical techniques, and implant-related factors to postoperative instability?
In order to answer those questions, the investigator team designed a retrospective case-cohort study and recently published the results, “Prior Instability is Strongly Associated With Dislocation After Isolated Head and Liner Exchange,” appears in the July 1, 2022 edition of The Journal of Arthroplasty.
“As revision THA (total hip arthroplasty) cases increase, and revision for hip instability takes a larger proportion of early revision THA cases, it is important to understand the revision options the surgeon has in their toolbox,” said co-author Ran Schwarzkopf, M.D., an orthopedic surgeon with Langone, to OTW. “We wanted to compare outcomes between different indications for head and liner only revision and evaluate reasons for need of re-revision.”
The researchers considered 209 hips that underwent a head and liner exchange between 2011 and 2019 (>2 years’ follow-up). Surgical indications were acetabular liner wear in 86 hips (41%), instability in 40 hips (19%), and infection in 36 hips (17%). Of the 209 hips, 47 (23%) had undergone a prior revision, while 54 had a prior THA dislocation (26%). For revision, the majority of hips involved a head size ≥32 mm (167 hips, 80%), and neck length >0 mm (133 hips, 64%). Elevated liners were used for 85 hips (41%); neutral liners were used for 63 hips (30%).
A posterior approach was used for the majority of patients (177 patients, 85%). The team found that the soft tissues surrounding the hip were compromised in 53 hips (25%). Regarding the Lewinnek safe zone, 72 cups (34%) were outside this area. A total of 28 hips (13%) experienced a dislocation within two years postop.
Dr. Schwarzkopf said to OTW, “The most interesting and clinically important finding was the increased risk, 7-fold, for post-revision instability/dislocation event, in cases that had a head and liner revision for instability (indication for index revision THA).”
“I think surgeons need to take this increased risk of recurrent instability in cases that were revised for instability with a head and liner exchange only,” added Dr. Schwarzkopf. “Surgeons should evaluate these cases closely to assess if a more involved revision is needed with possibly a femoral and/or cup revision as a better option than head and liner exchange only.”
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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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