CORR Insights: What Are the Mortality, Infection, and Nonunion Rates After Periprosthetic Femoral Fractures in the United States?

Where Are We Now?

Periprosthetic femoral fractures are devastating injuries with high associated morbidity [6], mortality [6], and economic costs [2, 4]. Periprosthetic fractures have often been compared with geriatric hip fractures [3], which are widely recognized as morbid, life-altering injuries. In contrast to geriatric hip fractures, periprosthetic femoral fractures have multiple layers of added complexity: location (proximal, shaft, or distal), affected joint (knee or hip), and a wide array of treatment options including nonoperative treatment, internal fixation, revision arthroplasty, and endoprosthetic reconstruction. For this reason, periprosthetic fractures are challenging to study, especially in large-database studies where inherent limitations related to pertinent clinical details (for example, fracture pattern, fixation or revision construct, and bone quality) make it particularly difficult to group fractures with similar morphology and treatment characteristics.

As the numbers of hip and knee replacements grow and life expectancy increases, so too will the incidence of periprosthetic fractures and their associated complications. Until recently, the degree to which the incidence of periprosthetic fractures has increased has been unclear because of the complexity of studying these injuries in large databases. Some of the largest studies to date were either long-term single-institution studies [1] or relied on a 1-year time period from the Nationwide Readmissions Database [9].

A study in this month’s Clinical Orthopaedics and Related Research® by Walter et al. [12] used the Medicare Physician Service Records Database to capture the incidence, mortality, and complication rates of periprosthetic femur fractures from 2010 to 2019. Briefly, the authors found that the incidence rate of proximal periprosthetic femur fractures more than doubled from 2010 to 2019. The incidence rate of distal fractures more than tripled over the same time period. The 1-year and 5-year mortality rates after periprosthetic femur fractures in THA were 21% to 23% and 58% to 63%, respectively. Similarly, the 1-year and 5-year mortality rates after periprosthetic femur fractures in TKA were 22% to 27% and 57%, respectively.

The mortality rates cited by Walter et al. [12] should have us concerned. After all, the next time we counsel a patient with a periprosthetic femur fracture about their long-term outlook, how many of us will mention that more than half of patients won’t live past 5 years? For reference, reported rates of 1-year mortality after native hip fracture range from 17% to 21% in recent studies [7, 8, 11]. Based on the findings by Walter et al. [12], surgeons should counsel patients about the major risk of morbidity and mortality after periprosthetic fracture, consider a multidisciplinary approach to periprosthetic fracture care (similar to that commonly used in geriatric hip fractures) to mitigate some of these risks, and advocate for appropriate training in periprosthetic fracture care among orthopaedic trainees.

Where Do We Need To Go?

The study by Walter et al. [12] is an important step toward better understanding the epidemiology of periprosthetic fractures. However, much work remains to be done. The numbers cited in this study are sobering. The rapid growth in periprosthetic fracture rates over just 10 years highlights the need for providers who are comfortable managing these injuries, which can often be quite complex, necessitating experience in trauma and revision arthroplasty.

Treatment factors were not evaluated in the current study. However, because operative management can vary dramatically based on patient and fracture characteristics, this is an important area for further study. Similarly, the current study categorized fractures according to ICD-9 and ICD-10 codes, which do not capture critical information related to fracture severity or morphology. These characteristics can dramatically impact a patient’s treatment plan and prognosis.

Overall, the study by Walter et al. [12] answers some questions and raises others. First, how can we prevent these injuries in order to decrease, or least slow, the incidence of periprosthetic femoral fractures? Second, how can we decrease complications and prolong survival after periprosthetic femoral fracture, and minimize the morbidity and mortality described in this study? Third, how do we reach a broader consensus on the optimal treatment for different fracture patterns?

How Do We Get There?

These are questions with no simple answers, but there are some reasonable steps forward.

First, being cognizant of the known patient-related risk factors for periprosthetic fracture and tailoring operative decisions to those factors can help prevent periprosthetic femoral fractures. These factors include advanced age, osteoporosis, and fall risk, to name a few. Cemented fixation should be considered any time a patient presents for primary arthroplasty and has these risk factors. There are clear data suggesting a decreased risk of proximal periprosthetic femoral fracture with cemented fixation, yet there has been a simultaneous decrease in the use of cemented fixation. Fortunately, the pendulum may be swinging back toward cemented fixation in higher-risk patients. From my experience applying to adult reconstruction fellowship, I was pleasantly surprised to see many programs advertising how many cemented stems their fellows put in over 1 year. I’m guessing this is in response to trainees wanting more, not less, training in this vital skillset. Indeed, a recent survey of orthopaedic trainees suggested that many young surgeons do not feel they are receiving appropriate training in femoral cementation [10].

Second, we need to be better at treating these fractures to minimize morbidity and prolong survival. Part of this is that we need more providers who are comfortable with trauma and revision arthroplasty. Accreditation Council for Graduate Medical Education–accredited residency programs require residents to log a certain number of hip fracture cases. Perhaps a similar minimum should be instituted for periprosthetic fractures to ensure a basic level of understanding and familiarity with these injuries. Outside of the training realm, orthopaedic providers and hospitals should appreciate the resources required to effectively treat these complex injuries. Similar to patients with geriatric hip fractures, patients with periprosthetic femoral fractures may benefit from multidisciplinary care and advanced social support upon discharge [2].

Third, although the Vancouver classification system is helpful, reliable, and widely used, there are gray areas that merit further analysis. For example, there is ongoing debate about how to treat Vancouver Type B2 fractures, some of which may benefit from fixation over revision arthroplasty, or vice versa. More consensus and understanding related fixation approaches based on fracture morphology, current implant type, and bone quality would be helpful in this regard. Better studies are merited. There are many variables to consider when studying periprosthetic femoral fractures, such as fracture pattern, existing implants, patient characteristics, and chosen treatment. For this reason, data granularity and clarity are particularly vital when studying periprosthetic femoral fractures. This is an area where institutional databases, which can capture these data with increased granularity over large national databases, can really shine. Additionally, there is a dearth of well-designed randomized controlled trials comparing two or more viable treatment options for periprosthetic fracture patterns. Part of this is because of heterogeneity in fracture patterns and the difficulty of randomizing older patients with high perioperative risk [5]. Large trauma centers and multicenter groups should address this dearth by designing large-scale randomized controlled trials that can provide prospective, less-biased data about optimal fixation for certain fracture patterns.