Bone Mineral Density and Fracture

The Plot Thickens: The Bones Thin

New Use(s)?

• Thigh bone connected to the blood stream

• Flexibility, strength and balance

• Custom models

Both Ends against the Middle

• Argument for Impact:

Mechanical stress activates osteocytes

• Argument against Impact:

Trauma initiates chondral degeneration

Osteoporosis and Osteoarthritis

• Osteoarthritis– Mechanoreceptors: Impact a must.Impact a must.

• Osteoporosis– Chondral Damage: No Impact.No Impact.

Osteoporosis vs Osteoarthritis

• Osteoarthritis– Mechanoreceptors: Impact a must.Impact a must.

• Osteoporosis– Chondral Damage: No Impact.No Impact.

Osteoporosis and Osteoarthritis

• Bone arises from cartilage:

Cartilage Bone Both

A Sliver Lining

Chondroblasts and ‘Clasts

Chondrocytes are Family Practitioners

Dynamic Support System

Feedback system

• Architectonic reflects lines of stress

• Buildup of bone reduces deformation

• Osteoporosis should increase response

Competitive Physiology

“Static loading does not prevent osteoporosis”

• Rubin, CT, Lanyon, LE, Baust, G: “Modulation of bone loss during calcium insufficiency by controlled dynamc

load.” Calcif Tis Int 1986;38:209-216.

Turkey wings lead the wayCompetitive Physiology

“Static loading does not prevent osteoporosis”

“Short periods of dynamic loading protect the bones in calcium-deficiency.”

• Rubin, CT, Lanyon, LE, Baust, G: “Modulation of bone loss during calcium insufficiency by controlled dynamc load.”

Calcif Tis Int 1986;38:209-216.

Turkey wings lead the way

• 3H uridine rises six-fold after loading1

• 8 seconds of loading = prevention2

• 72 seconds of loading > 30% - 40%2

• Nothing more with 720 or 3600 seconds2

• 1. Pead, MJ, Suswillo, R, Skerry, TM et al: “Increased 3H uridine levels in osteocytes following a single short period of dynamic bone loading in vivo.” Calcif Tisue Int 1988;43:93-97.

• 2. Rubin, CT, Lanyon, LE: “Regulation of bone formation by applied dynamic loads. J Bone Joint Surg 1984;66A:397-402.

Turkey wings lead the way

Eccentric pulls on periostium increase bone strength, reversing osteoporosis

Lanyon, L.E. “Osteoporosis and exercise.” Topics in Geriatric Rehabilitation. March 1989 4:(2)pp.12- 24.

Woolf, J: The Law of Bone Transformation. Berlin, A. Hirschwald, 1892.

Deforming force