biopoly - isakos cartilage symposium - shanghai june 2017

Prof. Vladimir BobićMD FRCSEd, Consultant Orthopaedic Knee Surgeon

Chester Knee Clinic at Nuffield Health, The Grosvenor Hospital Chester, United Kingdomwww.kneeclinic.info [email protected] @ChesterKnee

BioPoly®RS Knee System The partial resurfacing implant

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http://www.kneeclinic.info

mailto:[email protected]

Relevant Disclosures

1: Royalties received from Schwartz Biomedical3b: Paid Consultant for intellectual property (implant

and instrument design), Schwartz Biomedical

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Mr Mike McNicholasBSc, MD, FRCSEd(Tr&Orth), FFSEM RSCI

Consultant, University Hospital Aintree, LiverpoolHon 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

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@BioKneeSociety

Articular Cartilage Repair: Surgical Options

ACI/MACI

BioPoly: Filling the Void?

OATSMicrofracture

Allografts UKR & TKR4

BioPoly Femoral Resurfacing Implant

Articular Component: Patented Combination UHMWPE + HA5

Poly vs BioPoly

Wetability Hydrophilic

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Self-lubricating material for better wear

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• 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

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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 HookeC10 = 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.html2 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.php4 http://www.goodfellow.com/E/Polyethylene-UHMW.html

http://silver.neep.wisc.edu/~lakes/BoneTrab.html

http://www.fwmetals.com/titanium-wire-alloys.php

http://www.goodfellow.com/E/Polyethylene-UHMW.html

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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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 apexPeak -0.100

Additional load sharing zones

BioPoly loading FEA

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BioPoly - Deformed shape at 1000N (note larger area of tibial cartilage engaged in load sharing)

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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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®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

Patella15mm 20mm 15x24mm

15mm/0 15mm/1 20mm/0 20mm/1

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BioPoly RS Knee Surgical Technique

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The Race-track BioPoly RS Knee Surgical Technique

BioPoly Surgical Technique

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BioPoly Surgical Technique

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Race-track BioPoly

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Patellar BioPoly

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Patellar BioPoly

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Cemented all BioPoly Implant

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Current BioPoly® RS Partial Resurfacing3 Families of Products

BioPoly® RS KNEECE Marked

BioPoly® RS PATELLACE Marked

BioPoly® RS SHOULDERCE Marked

Patella HumeralheadDistal Femur

37+ BioPoly® RS Femoral Trochlea and Talar Dome in the pipeline

BioPoly® RS Partial Resurfacing Knee Implantations

5 yrs

600+ cases

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BioPoly® RS Partial Resurfacing Knee SystemTypical 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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Preoperative knee imaging

+ MRI and Arthroscopy for lesional characteristics

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Indications : Lesion Characteristics• Medial or Lateral femoral condyle, NOT tibial condyles

• Focal 2cm2 or (2.4 x 1.5) cm2 ≤3.1cm2 (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)

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Contradictions Lesion characteristics:

• Uncontained• Very large• >1 implant required• Kissing lesion

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Contradictions Other joint pathology

• Malalignment

• Laxity

• Major meniscal deficiency

• Subchondral sclerosis

• Advanced degenerative changes43

Registry Study: Preliminary Report

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Study Investigators and Collaborators:Prof Vladimir Bobic - Chester Knee Clinic, Chester, UKProf Mike McNicholas – Aintree, Liverpool, UKMr Dinesh Nathwani - Imperial College, London, UKProf Alister Hart - RNOH Stanmore, London, UKMr Jonathan Miles - RNOH Stanmore, London, UKMatt Hill - Schwartz Biomedical, USAHerb Schwartz - Schwartz Biomedical, USA

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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 CriteriaInclusion 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

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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Rotation of BioPoly Implant

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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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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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• BioPoly compared to historical microfracture outcomes– BioPoly patients on average 7 – 9 years older

• Significantly superior KOOS QoL and Sport after 2 years52

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OrthoBiologics vs Metal and Plastic

Hmmm ... not really. Not so soon, but will happen ... 55

biopoly - isakos cartilage symposium - shanghai june 2017

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