New Podcast Episode #34 Featuring Professor Justin Cobb (Imperial College London)
For decades, hip replacement has been considered one of the most successful operations in all of medicine. Modern implants routinely provide decades of pain relief, excellent function, and predictable outcomes for millions of patients worldwide.
But for younger, highly active patients, one question continues to generate debate:
Could hip resurfacing offer advantages over a traditional total hip replacement?
In Episode #34 of The Joint Replacement Podcast, I had the privilege of speaking with Professor Justin Cobb, orthopedic surgeon, engineer, and Professor at Imperial College London, whose career has been dedicated to advancing implant design, computer-assisted surgery, and the next generation of hip resurfacing technology.
This conversation explores where hip resurfacing has been, why it fell out of favor, and why many experts believe it may be entering a new chapter.
What Is Hip Resurfacing?
Unlike a traditional total hip replacement—which removes the femoral head and inserts a stem inside the femur—hip resurfacing preserves the patient’s femoral neck and most of the femoral head.
Instead of replacing the entire upper femur, the damaged joint surface is capped with a metal or ceramic implant while a matching acetabular component is placed into the socket.
The theoretical advantages include:
- Preservation of bone
- Larger femoral head size
- More natural biomechanics
- Easier revision if necessary
- Lower risk of instability
These potential benefits have made resurfacing particularly attractive for younger, active patients, although patient selection remains critical.
Why Did Hip Resurfacing Decline?
Hip resurfacing experienced tremendous enthusiasm in the early 2000s before concerns emerged regarding metal-on-metal bearings.
Research demonstrated that some implants generated excessive cobalt and chromium ions due to wear, particularly when acetabular components were malpositioned or used in smaller patients. These findings led to recalls of several implant systems and a dramatic decline in resurfacing worldwide.
Studies from national joint registries showed higher revision rates in certain patient populations, particularly women with smaller component sizes using first-generation metal-on-metal devices.
Key references:
- Smith AJ, Dieppe P, Porter M, Blom AW. Risk of cancer in first seven years after metal-on-metal hip replacement compared with other bearings. BMJ. 2012;344:e2383.
- National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. Annual Report.
- U.S. Food and Drug Administration. Information about Metal-on-Metal Hip Implants.
Why Is Hip Resurfacing Being Revisited?
Professor Cobb believes the story did not end with metal-on-metal implants.
His research has focused on developing a ceramic-on-ceramic hip resurfacing system, designed to preserve many of resurfacing’s biomechanical advantages while eliminating concerns regarding metal wear debris.
During our discussion, he explains how advances in:
- ceramic engineering
- implant manufacturing
- computer-assisted planning
- surgical instrumentation
may allow resurfacing to evolve beyond its earlier limitations.
Although these newer technologies continue to undergo clinical evaluation, they represent an exciting area of orthopedic innovation.
Hip Replacement vs Hip Resurfacing: Which Is Better?
The honest answer is:
It depends on the patient.
Modern total hip replacement remains the gold standard for the vast majority of individuals with hip arthritis.
Today’s implants have outstanding survivorship, with many studies demonstrating greater than 95% implant survival at 15–20 years in appropriate patients.
Total Hip Replacement Advantages
- Excellent long-term results
- Extensive clinical evidence
- Reliable pain relief
- Widely available
- Appropriate for nearly all patients
Potential Hip Resurfacing Advantages
- Bone preservation
- Larger femoral head
- Lower instability risk
- Potentially more natural hip mechanics
- Attractive option for carefully selected younger active patients
The challenge lies in identifying which patients truly benefit from each procedure.
Implant Design Matters
One of the most fascinating parts of our discussion centered on how orthopedic implants are actually developed.
Professor Cobb explains that creating a successful implant requires collaboration between:
- surgeons
- engineers
- biomechanical scientists
- materials experts
- manufacturing specialists
An implant is not simply a new shape.
It must demonstrate:
- biomechanical performance
- wear characteristics
- manufacturing reproducibility
- biological fixation
- long-term clinical safety
before widespread adoption.
This process often takes well over a decade from initial concept to routine clinical use.
The Future of Hip Replacement
Our conversation also explores what may define the next generation of joint replacement.
Potential advances include:
- Personalized implant positioning
- Improved robotics
- Artificial intelligence
- Advanced biomaterials
- Better understanding of hip biomechanics
- Bone-preserving implant designs
While no technology replaces surgical judgment, innovations continue making joint replacement more precise and individualized than ever before.
Key Takeaways
Hip resurfacing remains a topic of significant interest—particularly for younger, active patients.
Although traditional metal-on-metal resurfacing largely disappeared after well-documented complications, newer ceramic technologies may eventually expand treatment options for carefully selected individuals.
For now, modern total hip replacement continues to provide exceptional outcomes for the overwhelming majority of patients, while hip resurfacing remains a specialized procedure best performed by experienced surgeons in appropriately selected candidates.
As Professor Cobb emphasizes throughout our conversation, innovation should always be driven by one goal:
Helping patients regain function, relieve pain, and return to the activities they love.
Listen to Episode #34
🎙️ The Joint Replacement Podcast – Episode #34
Professor Justin Cobb (Imperial College London)
Topics include:
- Hip resurfacing vs total hip replacement
- Implant development
- Ceramic hip resurfacing
- Robotics and computer-assisted surgery
- Bone preservation
- Athletic performance after hip surgery
- The future of joint replacement
Search The Joint Replacement Podcast on YouTube, Spotify, Apple Podcasts, or wherever you listen to podcasts.
Selected References
- Learmonth ID, Young C, Rorabeck C. The operation of the century: total hip replacement. Lancet. 2007;370(9597):1508–1519.
- National Institute for Health and Care Excellence (NICE). Joint replacement (primary): hip, knee and shoulder. NG157. 2020.
- National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. Annual Report.
- U.S. Food and Drug Administration. Information about Metal-on-Metal Hip Implants.
- Smith AJ, Dieppe P, Porter M, Blom AW. Risk of cancer in first seven years after metal-on-metal hip replacement compared with other bearings. BMJ. 2012;344:e2383.
- Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Annual Report.
- Evans JT, Evans JP, Walker RW, Blom AW, Whitehouse MR, Sayers A. How long does a hip replacement last? A systematic review and meta-analysis of case series and national registry reports. Lancet. 2019;393:647–654.
- Abdel MP, Cross MB, Yasen AT, Haddad FS. The functional and financial impact of modern hip resurfacing. Bone Joint J. 2015;97-B(1):13–19.