1. Contemporary Solutions for Arthritis of the Knee

2. Arthritis affects over 70 million Americans
•2nd only to heart disease in causing disability
•1 million new patients diagnosed each year
• Affects 50% of people 65yrs or older
Source
Centers for Disease and Prevention, 2004.

3. Osteoarthritis is most common form of Arthritis
Rheumatoid arthritis
Post-traumatic arthritis
Inflammatory arthritis
Septic arthritis
All result in loss of joint cartilage
Healthy
Diseased

4. Factors that influence the onset of arthritis
Heredity / Family history
Age
Weight
Gender
Trauma / Repetitive stress
High impact sports
Other illnesses
Diseased compartment

5. The Knee is the #1 Joint Affected by Arthritis
Large weight bearing joint
Complex motion pattern
Common site of injury
Ligaments, meniscus

6. Presenting symptoms of Knee Arthritis
Stiffness
Swelling
Deformity
(“knocked-knee”/ “bow-legged”)
Crepitus (clicking, crunching, grinding)
PAIN
Start-up
Activity limiting
Nighttime

7. Diagnostic Studies Weight-bearing Radiographs A/P, Lateral, Notch view
Fairbanks Changes (subtle)
Joint space narrowing
Squaring of the condyles
Osteophytes
Sclerosis
MRI
Most helpful for ligaments and meniscal injury
Mechanical symptoms
“Symptoms don’t seem to fit”

8. Initial Conservative Treatments
Tylenol®
NSAID’s
(non-steroidal anti-inflammatory drugs)
Physical Therapy
Activity Modification
Weight Loss
Nutritional Supplements

9. The first level of invasiveness: Therapeutic Injections
Corticosteroid
Inter-articular anti-inflammatory agent
Short term symptomatic relief
Viscoelastic Series
Hyaluronic Acid injections: 3-5 shots
Attempts to augment normal joint lubrication properties
Potential for more long lasting relief (6mos-1yr)

10. The Orthopaedic Specialist
When conservative treatments no longer resolve activity limiting pain caused by osteoarthritis then . . .
Surgical and reconstructive treatments may be appropriate

11. Surgical Options for Knee Arthritis
Arthroscopy
Debridement
Meniscectomy
Chondroplasty
Osteotomy
Bone cut and re-aligned onto remaining good cartilage
Arthroplasty (Joint Replacement)
Uni-compartmental knee replacement (partial knee replacement)
Tri-compartmental knee replacement (total knee replacement)

12. Arthroscopic Debridement “clean out” or “scrape bone”
Somewhat unpredictable results
50 to 66 percent get relief for some period of time
Best for patients with mechanical symptoms (catching, locking and giving out)

13. Knee Osteotomy Re-align weight-bearing axis through “good” cartilage
Most popular before success of contemporary knee replacement
Useful for patients too young, heavy or active for knee implants
Early results acceptable, questionable durability

14. End-Stage Osteoarthritis  Knee Replacement
Uni-compartmental Knee Replacement
“Uni,” “partial replacement” or UKR
Tri-compartmental Knee Replacement
“total replacement” or TKR

15. Minimally Invasive Knee Replacement
Same implants as traditional knee replacements
Components
Femoral
Tibial
Patellar

16. Minimally Invasive Knee Replacement
Potential Benefits:
Less trauma to the knee
Less bleeding
Less pain
Cosmetically appealing (smaller scar)
Shorter hospital stay
Quicker recovery than traditional total knee replacement
Potential Complications and Risks
Factors that effect risks:
Skill of the surgeon
Age, weight and health of the patient
Patient compliance

17. Total Knee Replacement
Most common joint replaced
First performed in 1968
Nearly 400,000 TKR’s performed per year in US

18. Total Knee Replacement
Patient satisfaction typically 85-90%
Relieves pain
Restores mobility
Durability well documented at ~90%
Improvements in materials and techniques continue to increase effectiveness
Schai, P.A., T.S. Thornhill and R.D. Scott. "Total Knee Arthroplasty with the P.F.C. System: Results at a Minimum of Ten Years and Survivorship Analysis." JBJS Sept. 1998:

19. TKR: Who’s a candidate?
Many patients that could be helped by knee replacement don’t know about it or do not seek care
Lack of knowledge
Misconceptions
Fear
“Postoperative Patient Data”, DePuy Internal Study. Nov-Dec Sample size: 80 patients
How long do patients wait before they see their surgeon?

20. Important Patient Demographic Trends
Over 65yr group is the most rapidly expanding segment of our population
Increasing individual longevity will result in a greater number of individuals living long enough to be diagnosed with arthritis
(Average age of today’s total knee replacement patient is 67yrs)

21. Important Patient Demographic Trends
36% of TKR patients are between ages 40-64
This group of younger patients requiring TKR is increasing
Those individuals requiring treatment for their arthritis will need solutions with even greater durability

22. Common Misconceptions Delaying TKR Surgery
Too Young—Components will “wear out” and have to be revised
Too Active—Components will “wear out” prematurely and have to be revised
Too Heavy— Stresses on components will cause them to “wear out” or “break”

23. Kinematics of a traditional (fixed-bearing) TKR
Normal knee motion is a complex combination
Flexion/extension
Anterior/posterior translation
Internal/external rotation
Varus/valgus lift off

24. Leading Causes of TKR Failures
Component loosens
Surgical technique
Infections
Polyethylene component wears out
What causes this wear?
What can we do about it?

25. Addressing Polyethylene Wear
Wear is affected by
Implant design
Implant materials
Implant alignment (surgical technique)

26. Polyethylene Wear
One of the leading causes of implant failure over time
Osteolysis
Early Revision
Negative Effect/Perception of patient
Decreased Range of Indications
Implant design and materials chosen are two of the most significant things that can be done to minimize (or virtually eliminate) the effect

27. Implant Design & Materials
Stress = Load/Area
Area
Stress
Area
Stress

28. Implant Design & Materials – continued
Contact Stress Patches
Overall applied stress (force)
Surface contact area
Limitation in contact area results in relatively high level of Polyethylene stress (wear)
Sheer
Fixed Bearing System
Rotating Platform System

29. If Contact Stress is not Optimized
Results in relatively high level of Polyethylene stress (wear)

30. If alignment is not optimized…
10°
Predisposes to accelerated polyethylene wear

31. Today’s Implants The Goal of a TKR Implant Solutions
Restore normal function of the knee
Last as long as possible
Solutions
Fixed Bearing TKR System
A Mobile Bearing/ Rotating Platform TKR System

32. Fixed Bearing TKR Systems
Good clinical results
Designs of Fixed Bearing systems may not optimize wear reduction
Does not mimic all range of motion of the natural knee

33. The Rotating Platform Solution “Congruity with Mobility”
Constraint forces minimized by allowing bearing rotation
Articulates like the natural knee
Full and normal range of motion
Increased contact area results in reduced polyethylene stresses (wear)
94% reduction over Fixed Bearing Systems*
Shear forces at implant-bone interface minimized
Could minimize loosening
Outstanding clinical results for over 25 years
C.J. Bell, H.M.J. McEwen, P.I. Barnett, R. Farrar, M. Stone, J. Fisher, “Comparison of Wear in Fixed and Mobile-bearing Knee Designs,” Transactions of the 49th Annual Meeting of the Orthopaedic Research Society, New Orleans, La., 2003.
H. Maars, D.C. Barton, R.A. Jones, I.M. Wards, J. Fisher, “Comparative Wear Under Four Different Tribological Conditions of Acetylend Enhanced Cross-Linked UHMWPE,” Journal of Materials Science: Materials in Medicine 10 (1999)
C.J. Bell, P.S. Walker, S. Sathasivam, P.A. Campbell, G. Blunn. “Differences in Wear Between Fixed-bearing and Mobile-bearing knees.” Transactions of the 45th Annual Meeting of the Orthopaedic Research Society, Anaheim Calif., 1999.
P. Lewis; C. H. Rorarbeck, R.B. Bourne and P. Devane. “Posteromedial Tibial Polyethylene Failure in Total Knee Replacements.” CORR Feb. 1994:
A. Cadambi, G.A. Engh, K.A. Dwyer and T.N. Vinh. “Osteolysis of the Distal Femur After Total Knee Arthroplasty.” The Journal of Arthroplasty Dec. 1994:

34. Advantages of a Rotating Platform Knee Replacement “Show me the Data”
94% wear reduction with Rotating Platform vs Fixed bearing
Fig. 1 Average Wear Rate per Million Cycles
C.J. Bell, H.M.J. McEwen, P.I. Barnett, R. Farrar, M. Stone, J. Fisher, “Comparison of Wear in Fixed and Mobile-bearing Knee Designs,” Transactions of the 49th Annual Meeting of the Orthopaedic Research Society, New Orleans, La., 2003.
H. Maars, D.C. Barton, R.A. Jones, I.M. Wards, J. Fisher, “Comparative Wear Under Four Different Tribological Conditions of Acetylend Enhanced Cross-Linked UHMWPE,” Journal of Materials Science: Materials in Medicine 10 (1999)
C.J. Bell, P.S. Walker, S. Sathasivam, P.A. Campbell, G. Blunn. “Differences in Wear Between Fixed-bearing and Mobile-bearing knees.” Transactions of the 45th Annual Meeting of the Orthopaedic Research Society, Anaheim Calif., 1999.
P. Lewis; C. H. Rorarbeck, R.B. Bourne and P. Devane. “Posteromedial Tibial Polyethylene Failure in Total Knee Replacements.” CORR Feb. 1994:
A. Cadambi, G.A. Engh, K.A. Dwyer and T.N. Vinh. “Osteolysis of the Distal Femur After Total Knee Arthroplasty.” The Journal of Arthroplasty Dec. 1994:
McNulty, ASTM,2002

35. Implant Alignment Self Aligning Q-Angle Less Stress on Quadriceps
Reduced Lateral Release rate
Reduced Bleeding
Reduced Pain
Improved Recovery
Maximize Tibial Placement and Alignment
Extensor Mechanism Aligns w/ the Trochlear Groove
Promotes Patellar Tracking

36. Advantages of a Rotating Platform Knee Replacement “Show me the Data”
Twenty year evaluation of rotating platform mobile bearing knee replacements
Survivorship 97.7% at 16-20yr Buechel et al Clin Ortho 2001
Cemented rotating-platform total knee replacements 9-12yr follow-up
119 TKA’s, Survivorship 100% at 10yrs Callahan et al JBJS 2000

37. Contemporary Solutions for Arthritis of the Knee Summary
The number of patients suffering from arthritis of the knee is steadily growing
Of the patients suffering from knee arthritis nearly half may not seek treatment due to poor information or fear
Patients seeking care are younger, more active and more demanding
Total knee replacement is a reproducible, reliable and durable solution to end-stage knee arthritis

39. Thank You Sponsored by www.kneereplacement.com