Joint anatomy, design, and arthroses: Insights of the Utah paradigm
✍ Scribed by Frost, Harold M.
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 247 KB
- Volume
- 255
- Category
- Article
- ISSN
- 0003-276X
No coin nor oath required. For personal study only.
✦ Synopsis
This model of joint design argues 1) that excessive fatigue damage (MDx) in articular cartilage collagen can be the ''final cause'' of an arthrosis; 2) that known responses of a growing joint's anatomy and geometry, and modeling and maintenance activities, to mechanical loads minimize that cause and thus arthroses; 3) and many biomechanical, biochemical, cellbiologic, genetic and traumatic ''first causes'' of arthroses could lead to that final cause.
The model depends partly on the following facts (marked by a single asterisk) and ideas (marked by a double asterisk). A) During growth a joint's total loads can increase over 20 times* without causing an arthrosis,* yet in adults an equal loading increase would cause one.* B) Fatigue damage (MDx) occurs in joint tissues,* larger strains increase it,* and minimizing strains reduces it.* C) Bone can repair amounts of MDx below an ''MDx threshold,''* but larger amounts can escape repair and accumulate.* The model assumes articular cartilage has similar features.** D) Bone modeling makes bones strong enough to keep their strains below bone's MDx threshold and minimize MDx.* Chondral modeling shapes and sizes joints during growth;* that would keep articular cartilage strains below the chondral MDx threshold** to minimize chondral MDx and arthroses.** Normal chondral modeling nearly stops in adults,* which might explain point A above.** E) Throughout life maintenance activities preserve optimal physical, chemical and biologic properties of a joint's tissues.*
To past emphases on the biochemical, genetic, cellular and molecular biologic features of adult joint physiology, this model adds organ-level, tissue-level and vital-biomechanical features of growing joints that invite study and understanding at lower levels of biologic organization.