THA stem design may have a larger impact on periprosthetic fracture risk vs. cement use
Key takeaways:
- Risk for periprosthetic fracture after THA may be more closely correlated with femoral stem design vs. use of cement.
- Researchers challenged the current cement-centric stem classification approach.
According to published results, stem design was the strongest predictor of postoperative periprosthetic femoral fracture after total hip arthroplasty, regardless of the use of cement.
“In this study, we challenge the conventional cement-centric stem classification approach and call for more nuanced categorization to better predict stem performance,” Josh N. Lamb, PhD, FRCS, consultant senior lecturer at the University of Bristol and a consultant lower limb arthroplasty surgeon at Wrightington Hospital in England, and colleagues wrote.
They added, “Stem design was strongly associated with [postoperative periprosthetic femoral fracture (POPFF)] risk, regardless of the presence of cement.”
Lamb and colleagues performed a cohort study of 809,832 primary THAs performed in England between January 2004 and December 2020 with a median follow-up of 6.5 years. The primary outcome measure was incidence of POPFF.
Overall, periprosthetic femoral fracture occurred in 0.6% of THAs (n = 5,100). Lamb and colleagues noted most fractures were treated with fixation after cemented stem implantation.
Lamb and colleagues found adjusted prosthesis time incidence rates for periprosthetic fracture, defined as the absolute incidence per 1,000 prosthesis-years of observation, were significantly associated with stem design, regardless of cement use.
They found cemented composite beam stems were associated with the lowest risk for periprosthetic fracture. They also found collared cementless stems were associated with a similar or decreased risk for periprosthetic fracture compared with polished taper slip cemented stems, the “current gold standard,” according to Lamb and colleagues.
“This study showed that POPFF accounts for one-quarter of all reoperations and that there is a large variation in the risk of POPFF according to femoral stem design, regardless of whether the stem is fixed with cement or not,” Lamb and colleagues wrote.
They concluded, “Researchers and policymakers should consider whether classifying stems simply by the presence of cement offers the utility required by the surgeons and patients whom it affects.”
Perspective
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The article “The risk of postoperative periprosthetic femoral fracture after total hip arthroplasty depends more on stem design than cement use: An analysis of National Health Data from England” by Josh N. Lamb, PhD, FRCS, and colleagues was a well-done national database cohort study designed to evaluate the risk of surgically treated postoperative periprosthetic femur fractures concerning the type of femoral stem used during the primary surgery. I commend the authors for thoroughly analyzing a comprehensive database that provides the incidence of fractures within their population. Their finding that cemented composite beam stems have the lowest fracture risk aligns with existing literature.
As a practicing arthroplasty surgeon, I am uncertain whether these data are as actionable as the discussion suggests. Specifically, concerning stem selection during primary surgery, the periprosthetic fractures we aim to prevent are the intraoperative and immediate postoperative types, not late postoperative fractures. For this reason, many surgeons advocate using cemented femoral components for patients with osteopenia or osteoporosis. Although, recent data from the American Joint Replacement Registry challenge this idea, suggesting that collared cementless stems may be associated with a lower risk of revision due to fracture when compared with cemented stems. The present study provides insight into the potential reason for this association, and I agree with the authors’ conclusion that a more nuanced categorization of stem performance would benefit surgeons, patients and health care systems.
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