Insights from Dr. Michael Kheir | The Joint Replacement Podcast Episode #22
Joint replacement surgery has transformed millions of lives, but the technology, implants, and surgical techniques continue to evolve rapidly.
In Episode #22 of The Joint Replacement Podcast, I sat down with Dr. Michael Kheir, orthopedic surgeon, Director of Research, and Assistant Professor at the University of Michigan, to discuss some of the most important questions patients ask about hip and knee replacement today.
From robotic surgery and implant longevity to revision surgery and infection prevention, Dr. Kheir shared practical insights that can help patients better understand their options and set realistic expectations before surgery.
What Inspired Dr. Kheir to Become a Joint Replacement Surgeon?
Dr. Kheir’s journey into orthopedics began with a personal experience. As a child, he watched his grandmother struggle with severe knee arthritis before undergoing staged bilateral knee replacements.
The transformation was dramatic.
After surgery, she regained her mobility and quality of life, leaving a lasting impression that ultimately helped shape his career.
Today, Dr. Kheir specializes in primary and revision hip and knee replacement while leading research efforts focused on improving outcomes and solving some of arthroplasty’s most difficult challenges.
How Long Do Modern Hip and Knee Replacements Last?
One of the most common questions patients ask is:
“How long will my replacement last?”
According to Dr. Kheir:
Hip Replacements
Modern hip replacements are expected to last approximately 20–35 years or longer.
Many of the survivorship studies currently available are based on older implant designs and polyethylene materials. Newer implants and highly cross-linked polyethylene may perform even better over time.
Knee Replacements
Modern knee replacements generally demonstrate excellent survivorship at 20 years and beyond, although outcomes depend on factors such as:
- Patient age
- Activity level
- Body weight
- Implant design
- Surgical technique
For many patients undergoing joint replacement after age 65, there is a good chance the implant will last for the remainder of their lifetime.
Why Implant Design Matters
One of the most interesting portions of our discussion focused on modern hip implant design.
Dr. Kheir highlighted the growing use of triple-tapered collared femoral stems, a newer generation of cementless hip implants designed to optimize fixation while reducing complications.
Potential advantages include:
- Improved rotational stability
- Reduced subsidence (implant settling)
- Enhanced biologic fixation
- Lower early revision rates
Registry data from Michigan and other large databases have demonstrated promising early survivorship with these modern stem designs.
For patients, the important takeaway is that implant design continues to evolve, with many modern implants showing excellent long-term durability.
Cemented vs. Cementless Hip Replacement
Not every patient receives the same type of implant fixation.
Cementless Fixation
Most younger and healthier patients receive cementless implants that allow bone to grow directly into the implant surface.
Benefits include:
- Biological fixation
- Excellent long-term durability
- Preservation of bone stock
Cemented Fixation
For older patients with osteoporotic bone, cemented fixation may offer advantages.
Dr. Kheir frequently considers cemented stems for:
- Elderly patients
- Patients with poor bone quality
- Patients with wide femoral canals (Dorr C bone)
Research continues to show that cemented fixation may reduce the risk of intraoperative and postoperative femur fractures in selected patients.
The key message is that implant fixation should be individualized rather than applying a one-size-fits-all approach.
Robotic Hip Replacement and Personalized Surgery
Robotics remains one of the most rapidly growing areas in joint replacement surgery.
Dr. Kheir utilizes robotic-assisted hip replacement to help optimize implant positioning and account for each patient’s unique anatomy.
Modern robotic systems allow surgeons to:
- Create a detailed 3D surgical plan before surgery
- Evaluate implant sizing
- Assess leg length restoration
- Analyze hip stability
- Account for spinal alignment and pelvic motion
One particularly important advancement is the ability to evaluate the relationship between the spine and pelvis.
Patients with spinal stiffness often require individualized implant positioning to reduce the risk of instability and dislocation.
These technologies allow surgeons to move beyond generic implant positioning and toward a more personalized approach.
Posterior vs. Anterior Hip Replacement
The debate between anterior and posterior hip replacement approaches continues throughout orthopedics.
Dr. Kheir performs a minimally invasive posterior approach combined with robotic technology.
His reasoning highlights an important principle:
The best surgical approach is often the one your surgeon performs most consistently and effectively.
Every approach carries advantages and disadvantages.
Anterior Approach Potential Benefits
- Lower dislocation rates
- Fluoroscopic guidance
- Muscle-sparing exposure
Posterior Approach Potential Benefits
- Excellent visualization
- Familiarity for many surgeons
- Flexibility in complex cases
- Easier revision surgery
Ultimately, surgeon experience often matters more than the specific incision location.
Solving One of Orthopedics’ Biggest Problems: Infection
Joint replacement infection remains one of the most devastating complications in arthroplasty.
Dr. Kheir’s academic practice frequently manages some of the most complex infected joint replacements in the region.
Several emerging technologies may help improve infection treatment in the future.
These include:
Antibiotic-Eluting Bone Void Fillers
Specialized materials can fill areas of bone loss while slowly releasing antibiotics directly into the surgical site.
Peptide-Based Therapies
Researchers are investigating new biologic treatments designed to attack bacteria more effectively.
Biofilm Disruption Technologies
Novel systems using alternating magnetic fields are being developed to disrupt bacterial biofilms that form on implant surfaces.
These technologies remain under investigation but may dramatically improve treatment options for patients with prosthetic joint infections.
Why Patient Education Improves Outcomes
One of the most valuable lessons Dr. Kheir learned during fellowship training was the importance of patient education.
Many complications, frustrations, and unrealistic expectations can be reduced when patients understand:
- Recovery timelines
- Activity expectations
- Potential complications
- Rehabilitation requirements
Well-informed patients are often more confident and better prepared for recovery.
Dr. Kheir even developed concise educational guides and frequently asked question sheets to help patients better understand their surgical journey.
The “20-20-20 Rule” After Knee Replacement
For knee replacement patients, Dr. Kheir recommends a simple recovery framework:
20-20-20 Rule
- 20 minutes of motion exercises
- 20 minutes of elevation and rest
- 20 minutes of icing
The goal is to balance movement with swelling control.
Many patients focus heavily on exercise while underestimating the importance of reducing inflammation during the early recovery period.
A calmer knee often becomes a better-moving knee.
Key Takeaways for Patients
If you’re considering hip or knee replacement, Dr. Kheir’s advice can be summarized in several important points:
- Modern joint replacements are highly durable.
- Implant selection should be individualized.
- Robotics can improve surgical planning and precision.
- Patient education significantly improves outcomes.
- Walking early after surgery is critical.
- Infection research continues to advance rapidly.
- The surgeon’s experience often matters more than the specific implant or approach.
Joint replacement continues to evolve through better implants, improved technology, and ongoing research aimed at helping patients achieve safer surgeries and better long-term outcomes.
Listen to the Full Episode
To hear the complete conversation with Dr. Michael Kheir, including detailed discussions on robotics, revision surgery, implant design, infection treatment, and recovery strategies, watch Episode #22 of The Joint Replacement Podcast.
The Joint Replacement Podcast
Hosted by Matthew Sloan, MD
Helping patients understand hip and knee replacement—and the surgeons who perform it.
Citations
- Australian Orthopaedic Association National Joint Replacement Registry Annual Report.
- American Joint Replacement Registry (AJRR) Annual Report.
- Evans JT et al. How Long Does a Hip Replacement Last? Lancet, 2019.
- Evans JT et al. How Long Does a Knee Replacement Last? Lancet, 2019.
- Abdel MP, Berry DJ. Contemporary Total Hip Arthroplasty Outcomes.
- Parvizi J, Gehrke T. Prevention and Management of Periprosthetic Joint Infection.