When we plan for a total hip arthroplasty (THA)—a hip replacement—the focus is often on the joint itself: the degree of wear, bone quality, alignment, pain, and mobility. But this study reminds us an important truth: your medical comorbidities (other health conditions you have) significantly influence not just your risk, but also the costs across the entire episode of care. PubMed
In an era of bundled payments and value-based care, understanding what drives costs—and what risks you may face—is crucial both for patients and providers.
What the Study Did & What It Found
Study Overview
- The researchers used a large database (PearlDiver) to identify 250,343 patients who underwent primary hip replacement between 2007 and 2015. PubMed
- Patients were stratified based on having various medical comorbidities (e.g. obesity, kidney disease, COPD, cirrhosis, etc.). PubMed
- They compared reimbursements (i.e. what insurers paid) on the day of surgery and over the 90-day postoperative period among patients with and without comorbidities. PubMed
Key Findings
- Day-of-surgery costs / reimbursements
- Patients with comorbidities such as cirrhosis, morbid obesity, obesity, chronic kidney disease (CKD), and hepatitis C had the highest reimbursements on the surgical day. PubMed
- This suggests more resources, complexity, or precautions are needed even during the surgical encounter when patients have higher medical risk.
- 90-day postoperative period
- Over the 3 months after surgery, comorbidities like cirrhosis, hepatitis C, COPD, atrial fibrillation, and CKD were associated with substantially higher reimbursements (i.e. higher overall cost burden) compared to patients without these conditions. PubMed
- These comorbidities likely drive additional resource use: more monitoring, complications, readmissions, more intensive rehabilitation, or extended care.
In short: having certain medical conditions can considerably raise the “price of success” for hip replacement—not just in money, but in complexity, vigilance, and postoperative challenges.
What This Means for You as a Patient (Hip or Knee Replacement)
Although this study is specific to hips, the principles translate to knee replacements too. Here’s what patients should understand:
1. Your body’s “baseline” health matters
A joint replacement operation is not just about the bone or cartilage. Your circulation, organ function, metabolic control, respiratory health, and systemic resilience all play into how smoothly things go—how well you heal, how likely complications are, and how much extra care is needed.
2. Preoperative optimization is key
If you have comorbidities (kidney disease, liver disease, heart rhythm problems, lung disease, obesity, etc.), preparing them beforehand makes a difference. That might mean:
- Working with your primary care doctor or specialist to stabilize these conditions
- Improving nutrition, controlling blood pressure, optimizing kidney function, or treating liver disease
- Smoking cessation, weight loss, respiratory therapy, or cardiac evaluation as needed
The goal is to reduce surgical and postoperative risk, and ultimately reduce extra cost, complications, and stress.
3. Be realistic about recovery complexity
With comorbidities, you may require:
- More intensive monitoring after surgery
- Greater vigilance for complications (infections, organ dysfunction, wound healing issues)
- Higher likelihood of additional services (inpatient rehab, prolonged physiotherapy, readmissions)
Understanding this up front helps set expectations and fosters better planning.
4. Choose a surgeon and team who account for the “whole you”
When evaluating surgeons, ask:
- How do you assess and plan for patients with medical comorbidities?
- What steps do you take to reduce risk in the 90-day postoperative period?
- How will my extra health factors (like kidney disease or COPD) change your surgical plan or follow-up care?
A surgeon who considers just the joint—but not your broader health—is missing half the picture.
How I Use These Insights in My Hip & Knee Practice
As your hip & knee replacement specialist, here’s how I apply the lessons from this study:
- Comprehensive preoperative evaluation
Before recommending surgery, I evaluate your full medical profile. If you have comorbidities, I work with your other doctors to optimize them—kidney, liver, heart, lung, metabolic, etc. - Risk-stratified surgical planning
Knowing the added risk, I adapt surgical and anesthesia plans: more conservative intraoperative protocols, enhanced monitoring, anticipating possible complications. - Aggressive postoperative vigilance
In the 90 days after surgery—the period shown as vulnerable in the study—I plan closer follow-up, early detection of issues, and rapid intervention when needed. - Transparent counseling and informed consent
I believe in discussing not only the benefits of hip or knee replacement but also realistically the risks, especially in patients with comorbidities, so you know what to expect and can plan accordingly.
Bottom Line
This study confirms what many experienced surgeons already know: the success of joint replacement doesn’t depend solely on the joint—it also depends heavily on the patient’s overall health. Comorbidities such as kidney disease, liver disease, lung disease, obesity, or arrhythmias can significantly increase complexity, cost, and risk in the months following surgery.
If you’re considering hip or knee replacement, let’s review your total health picture—not just your joint. Together, we’ll tailor a plan that maximizes your safety, outcome, and long-term joint durability.
Dr. Samuel Rosas, MD, PhD, MBA
Hip & Knee Replacement Specialist
Memorial Healthcare System – South Florida
“Healthy movement starts with strong, stable joints — and every ligament matters. My goal is to keep you walking, running, and living pain-free for decades.”