Vladimir Bobic and Mike McNicholas: An update on completed and published BioPoly UK registry study.

1. Prof. Vladimir Bobić
MD FRCSEd, Consultant Orthopaedic Knee Surgeon
Chester Knee Clinic at Nuffield Health, The Grosvenor Hospital Chester, United Kingdom
www.kneeclinic.info office@kneeclinic.info @ChesterKnee
BioPoly®RS Knee System
The partial resurfacing implant
1

2. Relevant Disclosures
1: Royalties received from Schwartz Biomedical
3b: Paid Consultant for intellectual property (implant
and instrument design), Schwartz Biomedical
2

3. Mr Mike McNicholas
BSc, MD, FRCSEd(Tr&Orth), FFSEM RSCI
Consultant, University Hospital Aintree, Liverpool
Hon Prof, Directorate of Sport, University of Salford
Hon Senior Lecturer, Department of Musculoskeletal Biology, University of Liverpool
BioPoly®
RS Knee System
The partial resurfacing implant
Cardiff, 3rd February 2017
3
@BioKneeSociety

4. Articular Cartilage Repair: Surgical Options
ACI/MACI
BioPoly: Filling the Void?
OATSMicrofracture
Allografts UKR & TKR
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5. BioPoly Femoral Resurfacing Implant
Articular Component: Patented Combination UHMWPE + HA
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6. Poly vs BioPoly
Wetability Hydrophilic
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7. Self-lubricating material for better wear
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8. • BioPoly® Material
– “Microcomposite” (UHMWPE and Hyaluronic Acid)
– Hydrophilic (water attracting) polymer
• Hyaluronic Acid within BioPoly®
– Attracts synovial fluid for lubrication
– Allows for articulation with cartilage
• No damage to opposing cartilage surfaces
• No damage to implant surface
• Resurfacing Applications
BioPoly® Technology Overview
Hyaluronic Acid
8

9. Material properties
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Material Density Modulus Poisson’s ratio Hyperelastic
Trabecular bone 1.8 g/cc1 1.15 GPa 0.22 NA
Cartilage 1 g/cc 10 MPa
0.495
(incompressible)
Neo Hooke
C10 = 1.672 MPa,
D1 = 0.0
Titanium 4.5 g/cc3 103 GPa 0.343 NA
Co-Cr 8.41 g/cc3 233 GPa 0.3 NA
UHMWPE
(unhydrated)
0.945 g/cc4 830 MPa 0.464 NA
1 http://silver.neep.wisc.edu/~lakes/BoneTrab.html
2 van Rietbergen B, Majumdar S, Pistoia W, et al. Assessment of cancellous bone
mechanical properties from micro-FE models based on micro-CT, pQCT and MR
images. Technol Health Care. 1998;6:413–420.
3 http://www.fwmetals.com/titanium-wire-alloys.php
4 http://www.goodfellow.com/E/Polyethylene-UHMW.html

10. FEA Comparison of Partial Resurfacing Femoral
Implants: BioPoly RS and a metallic implant
• Contact biomechanics between
femoral condyle focal defect implant
and the opposing tibial articulating surface.
• Resulting biomechanical interface:
Reduced contact stresses and strains
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11. Results: Compressive Strains
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Metallic Implant
Compressive Log
strains at the tibial
surface below
implant apex
Peak -0.3
BioPoly
Compressive Log
Strains at the tibial
surface below
implant apex
Peak -0.100
Additional load sharing zones

12. BioPoly loading FEA
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13. BioPoly - Deformed shape at 1000N
(note larger area of tibial cartilage engaged in load sharing)
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14. Results in lower opposing cartilage contact pressure
(2.5x body weight load)
BioPoly
Tibial Cartilage
Contact Pressure
Peak = 3.46 MPa
Active Contact Zone
Loaded Area ~ 471
mm2
Metal Implant
Tibial Cartilage
Contact Pressure
Peak = 7.24 MPa
Active Contact Zone
Loaded Area ~ 314 mm2
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15. ®Confidential
BioPoly RS Knee and Patella System
• CE Marked
• Suitable for cartilage defects in the distal
femur and patella up to 3.1 cm2
• Femoral Condyle and Trochlear Facet
Implants
– Ti64 grit blasted stems. Press fit or cemented
• Patella implants
– All BioPoly construction for cementation
• Simple surgical instrument set and
technique
• Existing reimbursement codes
Femoral Condyles and
Trochlear Facets
Patella
15mm 20mm 15x24mm
15mm/0 15mm/1 20mm/0 20mm/1
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16. BioPoly RS Knee Surgical Technique
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17. 17
The Race-track BioPoly RS Knee Surgical Technique

18. BioPoly Surgical Technique
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19. BioPoly Surgical Technique
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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

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BioPoly RS Knee Surgical Technique

32. Race-track BioPoly
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33. 33

34. Patellar BioPoly
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35. Patellar BioPoly
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36. Cemented all BioPoly Implant
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37. Current BioPoly® RS Partial Resurfacing
3 Families of Products
BioPoly® RS KNEE
CE Marked
BioPoly® RS PATELLA
CE Marked
BioPoly® RS SHOULDER
CE Marked
Patella
Humeral
head
Distal Femur
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+ BioPoly® RS Femoral Trochlea and Talar Dome in the pipeline

38. BioPoly
®
RS Partial Resurfacing Knee Implantations
5 yrs
600+ cases
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39. BioPoly® RS Partial Resurfacing Knee System
Typical Resurfacing Patient
▪ 21+ year old active adult
▪ Knee pain
▪ Too young for TKR
▪ Often failed Debridement, Microfracture,
OATS or ACI
▪ Patients wanting to regain active lifestyle
▪ Focal defects
▪ Femoral condyles
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40. Preoperative knee imaging
+ MRI and
Arthroscopy for
lesional characteristics
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41. Indications : Lesion Characteristics
• Medial or Lateral femoral condyle, NOT tibial condyles
• Focal 2cm
2
or (2.4 x 1.5) cm
2
≤3.1cm
2
(Entire lesion visualized in static knee through static arthroscope)
• ICRS grade 2, 3, or 4
• Contained ICRS 0/1
• Depth from articular surface < 4mm
• Good subchondral bone (MRI)
X41

42. Contradictions
Lesion characteristics:
• Uncontained
• Very large
• >1 implant required
• Kissing lesion
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43. Contradictions
Other joint pathology
• Malalignment
• Laxity
• Major meniscal deficiency
• Subchondral sclerosis
• Advanced degenerative changes
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44. Registry Study: Preliminary Report
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45. Study Investigators and Collaborators:
Prof Vladimir Bobic - Chester Knee Clinic, Chester, UK
Prof Mike McNicholas – Aintree, Liverpool, UK
Mr Dinesh Nathwani - Imperial College, London, UK
Prof Alister Hart - RNOH Stanmore, London, UK
Mr Jonathan Miles - RNOH Stanmore, London, UK
Matt Hill - Schwartz Biomedical, USA
Herb Schwartz - Schwartz Biomedical, USA
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46. Registry Study Design
• Study Type: Post-market registry
• 35 patients & 4 UK Centres
• Control: Historical microfracture outcomes
• Outcome measures: KOOS, VAS, Tegner, SF-36
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Major Inclusion and Exclusion Criteria
Inclusion Criteria Exclusion Criteria
• Age 21 years and older • Body Mass Index (BMI) ≥ 30
• Symptomatic lesions classified as ICRS grade 2, 3, or 4 • Generalized degenerative or autoimmune arthritis
• Lesion size ≤ 3.1cm2 circumscribed by normal or nearly normal
(ICRS grade 0 or 1) cartilage with an overall depth ≤ 4mm
from the articulating surface
• Uncorrected chronic malalignment of the knee*
• Uncorrected ligamentous instability*
• Uncorrected mechanically symptomatic meniscal tear or
total meniscectomy*
• Sufficient subchondral bone quality to support implant • Kissing lesion on tibia
• More than one implant required to accommodate lesion
• Use with opposing articulating tibial components
*Can be corrected during surgery

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48. Registry Study Results
• Interim results after 2
years indicate:
– Significant improvement in
all clinical outcomes
– One revision (2.9%) due to
subchondral bone disorder
– No differences between
younger and older patients
• Mean Defect size = 2.7cm2
• Over half of patient population (54.3%) failed previous
cartilage repair procedures
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49. Rotation of BioPoly Implant
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50. Failed BioPoly Implant
• Why? No structural or technical problems identified. No infection. Patient selection? Surgical technique?
• Very difficult to remove! Revised successfully with deep subchondral drilling + ChondroTissue patch.
• Possible reasons: inadequate osseous support (previous microfractures + failed MACI = failure of implant
to bone integration)
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51. Patient Adverse Events
• 1 Wound infection reported after 1/12
– Resolved quickly with medication
• 1 Patient began experiencing pain at 3/12
– Arthroscopy revealed implant intact, and loose
cartilage body as source of pain
– Removal of loose cartilage body resolved
2symptoms
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52. Registry Study Results
• BioPoly compared to historical microfracture outcomes
– BioPoly patients on average 7 – 9 years older
• Significantly superior KOOS QoL and Sport after 2 years
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Registry Study Results

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55. OrthoBiologics vs Metal and Plastic
Hmmm ... not really. Not so soon, but will happen ... 55