1. 3D Knee™ Longevity & Wear
Melinda K. Harman, PhD
3D Knee™ Longevity & Wear
3D Knee 3yr Clinical Results - Bologna 2008

2. Why Knees Fail? 212 consecutive revised TKA, 1997-2000
Melinda K. Harman, PhD
Why Knees Fail?
212 consecutive revised TKA,
Sharkey et al., CORR, 404, 2002
3D Knee 3yr Clinical Results - Bologna 2008

3. Melinda K. Harman, PhD
Key Observations
Contact area for many TKR designs decreases with increased flexion >20°
Bourne, Clin Orthop 2003
Small areas and high contact stress increases potential for PE wear and delamination
in vivo 6.6 years
Retrieved LCS (Harman, ISTA 2003)
3D Knee 3yr Clinical Results - Bologna 2008

4. Articular conformity impacts materials
Melinda K. Harman, PhD
Why Pivoting TKA?
Articular conformity impacts materials
Larger contact areas optimize load distribution during patient activity
Lower contact stresses decrease potential for polyethylene wear
3D Knee 3yr Clinical Results - Bologna 2008

5. 3D Knee™ Articular Design
Melinda K. Harman, PhD
3D Knee™ Articular Design
Fully congruent lateral compartment
Widened medial condyle
Constant sagittal profile > 70° flexion
3D Knee 3yr Clinical Results - Bologna 2008

6. 3D Knee™ Contact Area and Stress Evaluated Using Finite Element Models
Melinda K. Harman, PhD
“Activity Model” of Gait, Stair, Squat
Morra & Greenwald, ORL, Cleveland OH
2.5 – 4.5 BW loads
Flexion angles 0° - 135°
Non-linear UHMWPe material properties
Measured actual manufactured implants
3D Knee 3yr Clinical Results - Bologna 2008

7. Contact Area and Stress at Heel Strike
3D Knee™ vs. Fixed Bearing TKR Designs
Melinda K. Harman, PhD
Contact Area
100
200
300
400
Duracon
PFC Sigma
Curve
GenesisII CR
NKII Ultra
3D Knee
Contact Area (mm2)
Contact Stress 10 20 30 40
Duracon
PFC Sigma
Curve
GenesisII CR
NKII Ultra
3D Knee
Contact Stress (MPa)
Stress Range
Competitive data from: Morra, Harman, Greenwald: Computational models can predict polymer insert damage in total knee replacements. Surgery of the Knee 4th Edition (Eds. Insall & Scott), 1(13):271-83, 2006
3D Knee 3yr Clinical Results - Bologna 2008

8. Contact Area during High Flexion Activities
3D Knee™ vs. “High Flexion” TKR Designs
Melinda K. Harman, PhD
100
200
300
400
500
Legacy LPS-
Flex Fixed
PFC Sigma
RPF
3D Knee
Contact Area (mm2)
Squat (135)
Chair (90)
Stair (60)
Contact stresses < 20 MPa during stair climbing
Includes post/cam contact area
3D KneeTM has 32% - 61% greater contact area
during stair climbing compared to other “high flexion” designs
Competitive data from: Morra, Greenwald: Polymer insert stress in TKR designs during high flexion activities. AAOS 2005
3D Knee 3yr Clinical Results - Bologna 2008

9. Melinda K. Harman, PhD
III: 3DKneeTM Wear Test
3DKneeTM Wear Test
Industry Contract Between DJO Surgical and Clemson University
Clemson University BioTribology Laboratory
Testing occurred between June - December 2007
3D Knee 3yr Clinical Results - Bologna 2008 9

10. Dynamic Wear Test Data Avg. weight loss was less than other designs
Melinda K. Harman, PhD
Dynamic Wear Test Data
Instron/Stanmore 4-station force-controlled knee simulator
25% bovine serum at 37°C
5 million cycle tests
Avg. weight loss was less than other designs
3D Knee 3yr Clinical Results - Bologna 2008

11. Results: TKR Kinematics
Melinda K. Harman, PhD
III: 3DKneeTM Wear Test
Results: TKR Kinematics
Lateral Pivoting Observed During Walking
PLAY VIDEO
Simulator Video 2
3D Knee 3yr Clinical Results - Bologna 2008 11

12. Highly Cross-linked vs. Non-cross-linked
Melinda K. Harman, PhD
IV: Comparisons to the Literature
Highly Cross-linked vs. Non-cross-linked
GUR % BS
GUR 4150 ?% BS
GUR % BS
GUR % BS
DJO Surgical 3DKneeTM
3D Knee 3yr Clinical Results - Bologna 2008 12

13. Force vs. Displacement driven testing
IV: Comparisons to the Literature
Melinda K. Harman, PhD
GUR % BS
Force vs. Displacement driven testing
GUR 4150 ?% BS
GUR % BS
GUR 1050 ?% BS
DJO Surgical 3DKneeTM
3D Knee 3yr Clinical Results - Bologna 2008 13

14. 3D Knee™ – Retrieval Analysis
Melinda K. Harman, PhD
3D Knee™ – Retrieval Analysis
year follow-up
4 retrieved UHMWPe inserts
1 Male, 3 Female
Age at Index: 58-72
BMI: 27-33
Reasons for Revision
Infection (2) at 11 and 13 mos.
Hemarthrosis (1) at 7 mos.
Diabetic capsulitis (1) at 6 mos.
3D Knee 3yr Clinical Results - Bologna 2008

15. UHMWPe Articular Damage Pattern
Melinda K. Harman, PhD
UHMWPe Articular Damage Pattern
6 Mon.
L M
7 Mon.
L M
Dominant wear mode is burnishing, with some scratching & pitting
Damage consistent with observations from other designs with short functional duration
11 Mon.
L M
13 Mon.
L M
Scratches
Burnish
Pits
Creep
Striations
Delamination
Emb. Debris
Abrasion
Indistinguishable
3D Knee 3yr Clinical Results - Bologna 2008

16. Melinda K. Harman, PhD
V: Conclusions
Conclusions
Wear Testing Simulators at Clemson University Performed To ISO Force-Control Standards
3DKneeTM system exhibited very low wear rate
3DKneeTM simulation confirms lateral pivot design
3DKneeTM outperforms a majority of published competition
3D Knee 3yr Clinical Results - Bologna 2008 16

17. Analysis of 3D Knee™ Results: Clinical Outcomes at 5 Years
Melinda K. Harman, PhD
Analysis of 3D Knee™ Results: Clinical Outcomes at 5 Years
WA Hodge1,2,3, MK Harman2, A. Mori2, SA Banks2,3,4
1Hodge BioMotion Orthopaedics, Good Samaritan Medical Center, West Palm Beach, FL, USA
2Institute for Mobility & Longevity, West Palm Beach, FL, USA
3Dept. of Mechanical & Aero Engineering, Univ. of Florida, Gainesville, FL, USA
4Dept. of Orthopaedics & Rehabilitation, Univ. of Florida, Gainesville, FL, USA
Research grants have been received in support of these studies. One or more authors are paid consultants and/or receive royalties from DJO Surgical (Encore Medical).
3D Knee 3yr Clinical Results - Bologna 2008

18. Melinda K. Harman, PhD
5 Year Clinical Outcomes of “ACL substituting” TKR Design using Standard Approach
509 knees
Nov 2001-Aug 2008
235 males, 274 females
Age: 73+9 (30-93) yrs
Weight: (50-159) kg
BMI: 28+5 (19-55)
3D Knee 3yr Clinical Results - Bologna 2008 18

19. This study presents the first 100 TKR patients with 2-6 year follow up
Melinda K. Harman, PhD
“ACL substituting” TKR Patient Cohort operated by Dr. Hodge in West Palm Beach, Florida USA
Patients Excluded
6 patients (7 knees) deceased
4 Re-operations
Severe adhesive capsulitis secondary to diabetic episodes
Synovectomy and PE exchange for recurrent hemarthrosis
Late infection with debridement and polyethylene exchange
Patellar resurfacing secondary to patella maltracking,pain
1 Revision of all components, 2 patellar revisions in same patient
Late infection arising from complications of lumbar laminectomy
Patellar loosening (bilateral in 1 patient at 3 years)
This study presents the first 100 TKR patients with 2-6 year follow up
3D Knee 3yr Clinical Results - Bologna 2008 19

20. Initial 100 “ACL substituting” TKR with Average 4 Year Follow Up
Melinda K. Harman, PhD
Initial 100 “ACL substituting” TKR with Average 4 Year Follow Up
100 knees in 88 patients
Avg. follow-up: 4.2 (3-6) years
surgery Nov – Aug. 2004
45 males, 55 females
Age: 73+8 (43-88) years
Weight: (51-121) kg
BMI: 28+5 (20-40)
Diagnosis
OA - 90 knees
RA - 10 knees
3D Knee 3yr Clinical Results - Bologna 2008 20

21. Outcome Measures Knee Society Score (pain, function) Range of motion
Melinda K. Harman, PhD
JR090 at 2 yrs.
Outcome Measures
Knee Society Score (pain, function)
Range of motion
“Digital Goniometer” tool for computerized measurement of digital radiographs
3D Knee 3yr Clinical Results - Bologna 2008 21

22. Knee Society Scores (Pain/Motion)
Melinda K. Harman, PhD
Knee Society Scores (Pain/Motion)
Pre-Op
47+11
3 mos
92+11
1 year
96+7
2 year
98+4 20 40 60 80
100
Mean Knee Society Score (Pain/Motion)
5 years
97+5
3 year
97+7
3D Knee 3yr Clinical Results - Bologna 2008 22

23. Knee Society Scores (Function)
Melinda K. Harman, PhD
Knee Society Scores (Function)
Pre-Op
51+12
3 mos
85+20
1 year
95+11
2 year
95+10 20 40 60 80
100
Mean Knee Society Score (Function)
5 years
95+12
3 year
97+7
3D Knee 3yr Clinical Results - Bologna 2008 23

24. At last follow-up, 68% have > 120° of flexion
Melinda K. Harman, PhD
Passive Flexion
Pre-Op
107+8
3 mos
113+12
1 year
119+10
2 year
121+10 80 90
100
110
120
130
Mean Passive Flexion (deg)
5 years
3 year
At last follow-up, 68% have > 120° of flexion
3D Knee 3yr Clinical Results - Bologna 2008 24

25. Radiographic Results Pre-Op (3:1 varus : valgus)
Melinda K. Harman, PhD
Radiographic Results
Pre-Op (3:1 varus : valgus)
Varus 183° (176°-196°)
Valgus 170° (156°-175°)
Limb correction = 6° (0°-15°)
Post-op avg. 4 yrs.
AP Limb = 176°+3° valgus
Tibial Slope = 5°+4°
Patellar Tilt = 3°+3°
TKR radiolucent lines
4 TKR exhibited “wide” RLL at 5 years
All showed no progression from 3 years
3 patients had clinically recurrent effusions
3D Knee 3yr Clinical Results - Bologna 2008 25

26. West Palm Beach, Florida USA
Thank You
West Palm Beach, Florida USA