A new research study has highlighted the most common patient-related infection risk factors after total hip arthroplasty for acetabular fractures.
The retrospective study “Comparison of Patient Demographics and Patient Related Risk Factors for Infections After Primary Total Hip Arthroplasty for Acetabular Fractures” was published in the May 2021 issue of the Journal of American Academy of Orthopaedic Surgeons.
The study found evidence that weight extremes as well as iron deficiency anemia correlate to a higher risk of both surgical site infection and periprosthetic joint infection.
Total Hip Arthroplasty for Acetabular Fractures
Breaks in the acetabulum or pelvis are some of the most serious orthosurgical issues. They are often the result of a severe accident such as a motorcycle or vehicle accident or severe fall or, in more elderly patients, less impact falls.
Open reduction and internal fixation are considered the main treatment for displaced acetabular fractures, but with patients whose traumatic injuries are not suitable or who are predisposed to early posttraumatic arthritis, research indicates primary total hip arthroplasty (THA) is often considered more suitable.
Impetus for the Study
Matthew Ciminero, M.D., who is the study’s lead author, is also Administrative Chief Resident in the Department of Orthopaedic Surgery and Rehabilitation at Maimonides Medical Center and will be starting his Fellowship in Orthopaedic Trauma at University of California, San Francisco this Fall, explained the impetus for the study to OTW. “I have been interested specifically in trauma throughout my residency training and have sought to contribute to the field in whatever means possible.”
Joining Dr. Ciminero on the research team was Ivan J. Golub, M.D., Angelo Mannino, M.D., Rushabh M. Vakharia, M.D., Lisa K. Cannada, M.D., and Kevin Kang, M.D.
The overall intent of this work was to study total hip arthroplasty after acetabular fractures.
The study authors also noted how little this subject is covered in the literature. “Studies comparing patient demographics and identifying risk factors for either surgical site infections (SSIs) or periprosthetic joint infections (PJIs) are limited. Therefore, the purpose of this study was to (1) compare baseline demographics of patients who did and did not develop infections and (2) identify risk factors associated with developing either SSIs or PJIs.”
The researchers emphasized that “Acetabular fractures are a devastating, complex and challenging injury manifesting from high velocity traumatic injuries in younger patients to low-impact trauma in elderly patients. Because of the increasing prevalence of high-energy trauma cases in our society, surgical interventions for the treatment of acetabular fractures are becoming increasingly common in trauma centers.”
The Study
Dr. Ciminero and his colleagues used a national database to collect relevant data from 2005 to 2014 for their study. The authors found an interesting pattern in patient-related risk factors for infection. Dr. Ciminero summarized, “Risk of developing both surgical site infections and prosthetic joint infections were statistically significantly increased in the presence of associated obesity, pathologic weight loss, and iron deficiency anemia. Thus the extremes of weight contribute to a correlation of increased infection risk, as does anemia, as determined by a retrospective cohort review using a nationwide claims database.”
The research team looked for patients with an acetabular fracture who were treated with total hip arthroplasty and subsequently developed either surgical site infections (SSIs) or prosthetic joint infections (PJIs) “within 90 days or 2 years, respectively.” Patients who did not develop either infection were control subjects.
The study found 13,059 patients that met this criteria. The researchers closely compared baseline demographics utilizing a multivariate regression model to calculate the odds of postsurgical infection. “The study demonstrated significant differences among the cohorts regarding baseline demographics,” the authors wrote.
The researchers looked at a range of demographic profiles, including “age, sex, and the following comorbid conditions, such as alcohol use disorder, arrhythmias, body mass index (BMI), congestive heart failure, coagulopathies, chronic obstructive pulmonary disease (COPD), depressive disorders, diabetes mellitus, electrolyte/fluid imbalance, hypertension, hyperlipid emia, hypothyroidism, iron deficiency anemia, liver failure, lymphoma, metastatic cancer, neurological deficits, paralysis, peptic ulcer disease, peripheral vascular disease, renal failure, rheumatoid arthritis, tobacco use, valvular disorders, and pathologic weight loss.”
The most significant risk factors for SSI were (in order of risk level) morbid obesity (morbid or “severe” obesity is defined by the Center for Disease Control as having a Body Mass Index of over 40), pathologic weight loss, and iron deficiency anemia. Heightened risk of PJI was also associated with iron deficiency anemia, pathologic weight loss, and morbid obesity.
Iron deficiency anemia, a common condition of low red blood cell count, is easily treatable with supplement in most individuals. This research may highlight the importance of anemia screening before orthopedic surgery.
The authors concluded, “This study provides insight into orthopaedic surgeons and other healthcare professionals on the need of properly educating these high-risk patients of the potential consequences which they may encounter after their procedure.”
Potential Effects on Clinical Practice
“I believe this paper offers valuable information to the general orthopaedic surgeon, arthroplasty surgeon, and orthopaedic traumatologist,” Dr. Ciminero told OTW. One positive outcome is that this information can be provided to patients as they gather knowledge. “I think this study offers surgeons information that they can tell their patients when counseling on the risks of surgery to better inform their decision.”
The study emphasizes that high risk patients require appropriate education by health care professionals. For patients above or below average weight or with iron-deficiency anemia, this equates to a more fully informed patient experience. Research-based provider education on risk factors for infection may empower patients to make more informed decisions. Patient and provider awareness of risk factors for postoperative SSIs and PJIs can lead to improved outcomes for post-ortho surgery patients. Repeat hospital stays and ongoing treatment are not uncommon after invasive orthosurgical procedures.
In addition to possible improved patient health outcomes, hospital and insurance costs could potentially also be reduced with increased patient-related risk factor education. The research review indicated that increased mean hospital costs of care ranging from $12,689 for SSIs to PJIs treatment costs exceeding $1.62 billion this year. “With increasing patient longevity, it can be conjectured that orthopaedic surgeons will invariably encounter patients in their practice requiring this surgical modality for acetabular injuries,” the study stated.
More Research to Come, Hopefully
Dr. Ciminero remarked to OTW that the study also opens the door for further research on this topic. “The data that was extracted for this retrospective study was from 2005 to 2014. In recent years, there has been an increase in total hip arthroplasty performed for acetabular fractures, so it would be interesting to see if a sample size taken including the last 5-7 years would shed any new light on the information. Additionally, given the inherent retrospective nature of database studies, higher level evidence from prospective randomized trials would allow for more information regarding causality.”
Clinical setting and severity of risk factors are also areas of further potential research inquiry. As the researchers suggested, “Future prospective studies should assess the severity and duration of these risk factors and its association of developing infections in the setting of these traumatic injuries. In addition, investigators should assess and try to identify acutely modifiable risk factors and its association on infections within this population. A well-powered retrospective study involving multiple centers could potentially provide additional insight into the topic.”
