US Surgeons Ignore Evidence on Cement in Hip Fracture Repairs

Laird Harrison

Disclosures

June 29, 2017

Cemented Hip Joints Preferred for Elderly Patients

The evidence has become persuasive that elderly patients with fractured hips benefit more from cemented than uncemented arthroplasty, researchers say.

Despite these findings, more and more orthopedic surgeons in the United States are using press-fit fixation for this indication, says Karl Roberts, MD, who helped write the American Association of Orthopaedic Surgeons (AAOS) guidelines on hip fractures.

"I think if we followed these guidelines and moved toward cemented hip joints in elderly patients, we would see lower costs, better outcomes, and improved value," says Dr Roberts, a clinical associate professor at Michigan State University. Because they so often have weak bones, elderly patients who have broken their hips are at risk for periprosthetic fracture, he says.

One reason for the disconnect between evidence and practice could be that press-fit procedures are quicker, Dr Roberts says. In addition, many physicians are accustomed to using press-fit stems in total hip replacements of patients with osteoarthritis. In 2013, 86% of total hip replacements in the United States were uncemented.[1]

In osteoarthritis patients, uncemented fixation has a high rate of success. At the 2017 AAOS annual meeting, researchers from the Mayo Clinic in Rochester, Minnesota, presented a series of 532 total hip arthroplasties with polished double-tapered uncemented stems (Summit®; DePuy Synthes).

Ninety-nine percent of the stems survived after 15 years, with no femoral components revised for aseptic loosening. While there was no cemented fixation comparison group, "it's hard to say that anything is better than no failures," says coauthor Michael J. Taunton, MD, a Mayo assistant professor of orthopedic surgery. Surgeons removed or revised only four stems (0.8%) for infection and three (0.6%) for periprosthetic fracture.

As physicians become comfortable with uncemented arthroplasty, they may apply this approach to repairs of fractured hips. "Cemented stems in the United States are becoming a lost art," says Dr Taunton.

But people getting total hip replacements for osteoarthritis tend to be younger than people getting partial hip replacements for fractures. The population in the Mayo study had a mean age of 58, and Dr Taunton agrees with Dr Roberts that older patients with fractures are better off with cemented fixation. "A lot of people use uncemented stems for hip fractures, but the data is pretty good that the risk for fracture is greater in the uncemented group than in the cemented group," he says.

Concerns Over Cemented and Press-Fit Arthroplasty Risks

Another reason why some physicians may favor press-fit fixation could be concerns about bone cement implantation syndrome (BCIS). Though its etiology is not completely understood, the syndrome appears to result from emboli formed during cementation that cause hypoxia or hypotension and may lead to unexpected loss of consciousness and even death.

"Any time you're pressurizing cement in a femur, there is a risk that you could get intraoperative hypotension or [BCIS]," says Dr Taunton. "But as anesthesia techniques have improved, we haven't seen those problems as much."

Until recently, studies comparing the two approaches for hip fractures showed conflicting results. A 2011 Cochrane Review found no difference in adverse events.[2] But a 2013 update to the Cochrane review found an advantage for cemented fixation.[3]

And by 2014, when Dr Roberts and his colleagues reviewed the literature again, the evidence had mounted in favor of cemented fixation in fractured hips. They found eight studies of "moderate strength" comparing cemented to press-fit arthroplasty in the elderly. The studies showed a higher fracture risk with press-fit stems.

Hoping to help settle the controversy, a team from the Reinier de Graaf Group in Delft, The Netherlands,[4] randomly assigned 91 patients with displaced femoral neck fractures to hemiarthroplasty with uncemented fixation using a DB-10 stem (Zimmer-Biomet) and 110 to hemiarthroplasty with cemented fixation using a Müller Straight Stem from the same manufacturer.

The mean age was 84.0 in the uncemented group and 83.0 in the cemented group. The mean operation time was 57.3 minutes for the uncemented group and 55.4 minutes for the cemented group. There were 14 periprosthetic fractures in the uncemented group, compared with only three in the cemented group.

One patient in the cemented group suffered a peripheral nerve injury and another suffered an infection leading to a revision. There were five dislocations in the uncemented group and three in the cemented group. Overall, the uncemented group suffered significantly more major local complications (odds ratio, 3.36; 95% confidence interval, 1.40-8.11).

Minor local complications and systemic complications were comparable between the two groups. One patient died just after cement was injected into the femoral canal, but BCIS could not be confirmed.

Functional outcomes were also comparable, and there was no significant difference in postoperative mid-thigh pain at any point through 1 year of follow-up.

Surgeons observed subsidence in 13 (20%) of the uncemented and five (6%) of the cemented hemiarthroplasties, a statistically significant difference (P = .007). Of the four revisions, three were due to loosening, all in the uncemented group, and one for infection, in the cemented group.

"I think most of the literature now shows that there are more fractures with uncemented hips," says first author Sophie Moerman, MD. "In Europe there is a tendency to use a cemented hip in an older patient with hemiarthroplasty."

European and US Surgeons' Prosthesis Outcomes Differ

Why should European surgeons take a different approach from their US colleagues? One explanation could be the type of prosthesis. "This is primarily because different cemented stems have been used on different sides of the Atlantic, and the results of the cemented stems in the US have often been poor, whereas the results of the stems used in Europe have been good," wrote David W. Murray, MD, a consultant orthopedic surgeon at the University of Oxford, United Kingdom, in a 2013 essay tracing the history of the division.[5]

It's not always obvious which patients should get cemented fixation and which should get uncemented fixation, Dr Roberts acknowledges. A healthy 50-year-old patient who fractures a hip in a car accident might not need a cemented fixation. But someone 65 years of age or older who fractured a hip by falling from a standing height probably has weaker bones that could benefit from cement, he says.

In elective total hip replacements, there may be an even grayer area. "Certainly in 2017, a 55-year-old patient gets an uncemented, and for a 95-year-old, the majority of surgeons would do a cemented fixation," says Dr Taunton. "But when you get into the patients that are 70-80, what is the best solution for them?"

One way to make the decision is to refer to the Dorr femoral bone classification system, Dr Taunton says. Patients with bones classified as A or B can probably fare well with uncemented fixation, but those with a C might be better off with a cemented stem.

Dr Roberts is hopeful that trends will shift in the United States. He points out that press-fit stems are more expensive, so economics are on the side of cemented stems.

Perhaps more important, science usually wins out in the end. But it's slow. Findings from randomized trials typically take 10 years to translate to changes in practice. "Surgeons don't like to be told what to do," Dr Roberts says. "So it takes time. But we'll get there."

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