Bone Healing and Anatomy

Long Bone Structure

Reference: http://www.sirinet.net/~jgjohnso/modlongbones.jpg

Osteon

Haversion

Canal

Important terms to know….

• Diaphysis-shaft of long bone

• Metaphysis-growth area of long bone

• Epiphysis-ends of long bone

• Periosteum-outer sheath, blood and nerve supply

• Endosteum-inner sheath of long bone

• Compact bone=cortical bone

• Cortical Wall = 1/16 in – ¼ in

• Spongy bone=cancellous bone =trabecular bone=woven bone

Periosteum

Cortical Wall

Long Bone Structure

Short Bone Structure

Reference: http://health.allrefer.com/health/short-bones-short-bones.html

Composition of Bone

• 65 -75% Inorganic material:

hydroxyapetites (calcium, other mineral salts)

• 25-35% Organic material:

collagen, proteoglycans, proteins, bone growth factors

Cortical Bone• Provides stability; slow revascularization; dense material

(compact, lamellar)

• 5-30% porous

• Forms 80% of mature skeleton-Mechanical strength

Cancellous Bone

• Remodels faster; early revascularization with trabecular structure; blood flows thru it better. (Blood brings the cells, cells bring the healing).

• 30-90% porous

• Found in 20% of skeleton

Mechanisms of Bone Formation

Osteogenesis- capable of forming new bone from live cells (osteoblasts, pre-osteoblast cells)

-Source: Autograft, bone marrow

Osteoinduction- the formation of new bone by recipient mesenchymal cells that differentiate into bone

-Source: active BMP’s, DBM, demineralization process

Osteoconduction- inert scaffolding permits cell migration & ingrowth of new host bone. Creeping substitution

-Source: Allografts, ceramics, collagen

Remodeling/Wolff’s Law

• “Wolff's law" states that bone models and remodels in response to the mechanical stresses it experiences so as to produce a minimal-weight structure that is 'adapted' to its applied stresses.

• If loading on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading .

• Bone Heals Under Compression• Astronauts: weak bones• Weightlifts: more bone density

AO Basic Principles

• Anatomical reduction and compression

• Stable fixation

• Preservation of blood supply

• Early mobilization

Bones of the foot

Forefoot

Midfoot

Hindfoot

Bones of the foot

Bones of the forefoot

Tendons of the foot

Hammertoe Reconstruction

• Painful, affects mobility, limits footwear,

negatively impacts active lifestyle

• Causes: Genetics and Lifestyle:

Arthritis

Natural foot destabilization with age

Diabetes

Extended wear of high-heeled shoes

• Genetic predisposition creates likelihood of

multiple deformities per patient

• Average patient age is 52, 81% female

• Foot deformities affect 10-20% of U.S.

30-60 million individuals

• Patient growth driven by increasing diabetic

population, rate of osteoarthritis

0%

20%

40%

60%

Under 45 45 - 60 Over 60

Age Distribution of Hammertoe Patients1

Growing Patient Population

1. Thompson Reuters Assessment, CPT 28285, 2010.

Hammertoe

15

Hammertoe

Typical Symptoms

• Pain or irritation of the affected toe when wearing shoes.• Corns and calluses (a buildup of skin) on the toe, between two

toes, or on the ball of the foot. Corns are caused by constant friction against the shoe. They may be soft or hard, depending upon their location.

• Inflammation, redness, or a burning sensation• Contracture of the toe• In more severe cases of hammertoe, open sores may form.

Hammertoe Market

550,000 Hammertoe Surgeries

1,200,000 Diagnosed but Untreated

6 2011 iData Research Foot Ankle Report

30 – 60 Million

Hammertoe Sufferers6

US Hammertoe Surgery Market

Surgery- Legacy Standard of Care

• Varies based on severity (MPJ sometimes addressed)• Arthodesis or Arthroplasty- or a combination of both

• Major steps:• Preparation – Sometimes• Incision- dorsolinear over joint PIP• Capsulotomy• Tendon Release or transfer (extensor sometimes flexor)• Retrograde Wire into middle and distal phalanx• Wire back into proximal phalanx and sometimes

metatarsal

Surgical Treatment- Planning

Surgical Treatment - Incision

Surgical Treatment- Open

Surgical Treatment- Capsule, Tendon Release

Surgical Treatment- K-wire

Surgical Treatment- Kwire

Surgical Treatment - Bending

Surgical Treatment- the reality

Surgical Treatment- the reality

Growth Opportunity For Improved Hammertoe Solution

• $1B4 potential for next generation reconstruction device

draws from large, existing patient pool:

1.2M patients diagnosed but have not chosen

reconstruction

New patients from 30-60 million patient pool (10-20%

U.S. population1)

1. Scott R. AOFAS Poster Presentation, 2012.

2. Augoyard et. al., “Proximal Interphalangeal Arthrodesis, Using Intramedullary Bone Fastener…,” Memometal Technologies; 2007.

3. iData, U.S. Market for Small Bone & Joint Orthopedic Devices, June 2011.

4. Piper Jaffray, Stryker Research Report, 6 June 2011.

K-wire Fusion/Reconstruction:Legacy Standard of Care

Complicated recovery is deterrent to majority

of patients:

Open wound: wire protrudes for 6 weeks

Secondary trauma risk

Cannot shower, discomfort sleeping

Repeat visit to have K-wire pulled out

K-wire below 50% of surgeries by 20153

Reconstructions Accelerate With Availability Of K-wire Alternative

-

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

2007 2012 2017

Implants

K-wires

Pro

cedure

s1

29

Patient Brochures

“Happy Toes” Promotions & Website Help Surgeons Grow Practice

3030

More Supporting DataExisting Date Regarding K-wire

• 2.5% Failure Rate 1

• 18% Infection Rate 2

• 20% Non-union Rate 3

New Data Released 4

• Retrospective Comparison of Protoe to K-Wire

253 patients (190 K-wire, 63 ProToe)

Non-union rate

Pro-Toe- 31.7%

K-wire- 74.7%

Time to union

Pro-Toe – 9.3 weeks

K-wire – 8.6 weeks

No significant difference in fusion rates

1 Zingas C. Foot and Ankle International 1995 3 Caterini R. Foot and Ankle Int. 2004.

2 Reese AT. JR Coll Surg Edinb. 1987 4 Scott R. AOFAS Poster Presentation, 2012

Nextradesis™

2 weeks post-op

New Technology Introduction: Hammertoe Market Adoption Curve

Thank You