Physical Dimensions of Aging Musculoskeletal Changes: Bones & Joints PDF

HES 383 – PHYSICAL DIMENSIONS OF AGING MUSCULOSKELETAL CHANGES: BONES & JOINTS Prof Gina Whitaker, BSc Kin, PhD Sept 26th, 2023 The UBC Okanagan Campus and the City of Kelowna are located on the traditional, ancestral, and unceded territory of the Syilx Okanagan Nation. BONE - A&P REVIEW Bone is c...

HES 383 – PHYSICAL DIMENSIONS OF AGING MUSCULOSKELETAL CHANGES: BONES & JOINTS Prof Gina Whitaker, BSc Kin, PhD Sept 26th, 2023 The UBC Okanagan Campus and the City of Kelowna are located on the traditional, ancestral, and unceded territory of the Syilx Okanagan Nation. BONE - A&P REVIEW Bone is composed of: • Extracellular matrix ─ 65% Inorganic: Hydroxyapatite crystals - Ca5(PO4)3(OH) ─ 35% Organic: protein fibres – mostly collagen • Cells ─ Mature bone cells (osteocytes) ─ Osteoblasts, Osteoclasts ─ Osteogenic cells  develop into osteoblasts • Red & Yellow Bone Marrow • Cortical (compact) bone: 75-80% of skeletal mass • Trabecular (spongy) bone: 20-25% of skeletal mass BONE REMODELLING • Bone is continuously remodelling • Based on our body’s needs, to maintain homeostasis • Use-dependent: we can have localized areas of Formation > Resorption vs. Resorption > Formation depending on the use • Osteoblasts & Osteoclasts are involved in bone remodeling • OsteoBlasts  Bone FORMATION • OsteoClasts  Bone RESORPTION BONE MASS OVER THE YEARS Peak bone mass in early 20s • Peak bone mass highly determined by: genetics (60-80%) • The 2 prominent modifiable predictors of peak bone mass are: Physical Activity level & Nutrient intake (Protein, Ca2+,VitD, Mg2+) Age-independent predictors of bone loss: • Physical Inactivity, Smoking, High alcohol intake, Inadequate nutrient intake 5-10% difference in peak bone mass = 25-50% difference in hip fracture risk later in life AGE-RELATED BONE LOSS • Tightly linked to sex-hormone decline (estrogen & testosterone) • Decreased production of sex hormones  decreased osteoblasts and increased osteoclasts • Other humoral factors • Decreased Insulin-like growth factor & growth hormone  decreased bone remodeling • Increased Cytokines  increased osteoclast activity • Decreased VitD and Ca2+ absorption  increased bone resorption • Intrinsic effects of ageing on bone • Impaired osteoblast production from osteogenic stem cells • Decreased ability for cells to sense and respond to mechanical forces MORPHOLOGICAL CHANGES OF BONE WITH AGE • Loss of bone mass & mineral content • Reduced Calcium and Phosphate stores • Altered bone shape and geometry • Increased bone marrow fat content (yellow bone marrow) PATTERNS OF AGE-RELATED BONE LOSS IN WOMEN & MEN Males – steady decline of cortical and trabecular bone ~2% per year, slightly more trabecular bone loss Females over 10 year menopausal time period: ~30% loss of trabecular bone mass ~10% loss of cortical bone mass BMD = bone mineral density Dashed lines: trabecular bone Solid lines: cortical bone Corrado A, Cici D, Rotondo C, Maruotti N, Cantatore FP. Molecular Basis of Bone Aging. International Journal of Molecular Sciences. 2020; 21(10):3679. https://doi.org/10.3390/ijms21103679 OSTEOPOROSIS • “Porous Bones” • Trabecular bone loss and thinning • Cortical bone becomes porous and thin NORMAL VS. OSTEOPOROTIC METACARPAL BONE OSTEOPOROSIS C ANADA IMPACT REPORT 2018 OSTEOPOROSIS – RISK FACTORS NON-MODIFIABLE MODIFIABLE • Age (>65 YO) • Low Ca2+ and/or Vit D intake (or absorption) • Genetics • Tobacco use • Sex – approx.1:3 females and 1:5 males will suffer from an OP fracture during their lifetime • Alcohol intake (>2 servings per day on a regular basis interferes with Ca2+ absorption) • Caucasian or Asian descent • Prolonged use of certain drugs (e.g. glucocorticoids) • Inactivity / Sedentary lifestyle AGE-SPECIFIC INCIDENCE RATES FOR FRACTURES AT 3 COMMON LOCATIONS Falls are the leading cause of hip fractures among older adults SPINAL COMPRESSION FRACTURES • Source of chronic pain • Difficult to rehabilitate • Back brace • Osteoporosis meds: bone strengthening • Cement injections • Spinal fusion surgery OSTEOPOROSIS – SIGNS/SYMPTOMS & TREATMENT Signs & Symptoms • Abnormal curvature of the spine • Height decrease • Fragility / spontaneous fracture • Back pain from compression fractures in the spine Treatment • Dietary supplements: Ca2+,Vit D • Exercise: Strength Training & Weight-bearing • Pharmaceuticals that inhibit bone resorption or promotes bone formation Fragility Fracture: any fall from standing height or less that results in a fracture. DIAGNOSING OSTEOPOROSIS • Bone Mineral Density Testing • DXA scan • Usually of femur or spine • T-score (your bone density compared to standards of healthy young adults aged 25-35) • Measured at Femoral neck or Lumbar spine FRACTURE RISK CALCULATORS • Assesses 10 year risk of Osteoporosis • Good clinical tools for prevention • CAROC (Canadian Association of Radiologists & Osteoporosis Canada) • Includes Age, Sex, BMD measurement • Other considerations: any fracture after 40, recent prolonged glucocorticoid use • Low (<10%) / Mod (10-20%) / High (>20%) risk categories • FRAX (Fracture Risk Assessment System, WHO) • Computer-based questionnaire https://www.sheffield.ac.uk/FRAX/ • BMD measurement optional Fracture Risk Assessment (Canada) RECALL: THE VICIOUS TRIAD • The vicious cycle: Muscle and bone loss, and visceral fat accumulation with aging, combined with increase total adiposity  chronic inflammation  favors more muscle and bone breakdown • The vicious triad: can lead to Osteosarcopenic Obesity Syndrome • A multimorbid state that predisposes an individual to morbidity • Increased risk of weakness and imbalance, falls, fractures, further decline in function, frailty, disease JefariNasabia P, et.al. (2017). Aging human body: changes in bone, muscle and body fat with consequent changes in nutrient intake. Journal of Endocrinology 234(1):R37-51 EXERCISE FOR PREVENTION & TREATMENT OF OP • Avoid sedentary lifestyle • Weight-bearing activity maintains bone strength • Osteoporosis Canada Guidelines Include: • Strength training • Bone strength & muscle strength • Incorporate Balance training • Considerations • High risk of fracture should be considered when prescribing exercise • Avoid high-impact if high risk • Consider fall risk THE 3 F- WORDS FUNCTIONAL FUN FREE USING HIP PADS AS A PREVENTION TOOL AGE-RELATED DECLINE IN JOINT FUNCTION SYNOVIAL JOINTS – BASIC A&P REVIEW • Synovial joints are the freely moveable (within the range of motion) joints • The articulating bone ends are lined with hyaline cartilage (articular cartilage) • Joint cavity is filled with synovial fluid (secreted into the joint cavity by the synovial membrane) • Movement facilitation • Protection • Nutrients to the cartilage  Some joint cavities contain Meniscus • A fibrous joint capsule protects entire joint - Pads of fibrocartilage - Help stabilize joint and extra shock absorber • Attaches to bone, reinforced by ligaments  Some joints contain Bursae between tendons & ligaments - Fluid filled sacs that provide extra cushioning AGE-RELATED JOINT WEAR & TEAR • All of our joints experience wear & tear with age • Our weight-bearing joints – knees, hips, spine, big toes are the most prone to wear and tear damage. • With aging: • Articular cartilage: thinning, decreased tensile stiffness, reduced water content • Decreased water content in the joint capsule • Increased fibrous tissue growth Increased stiffness, mild aches & pains Decreased joint range of motion OSTEOARTHRITIS Osteoarthritis is the body’s failed attempt at repairing joint damage from wear & tear • Characterized by a progressive degradation of articular cartilage along with synovitis and bone remodelling • Severe enough to cause local debilitating pain • Affects 1:3 people in their lifetime (over half of people aged 65+) • Most common in Hands, Knees, Hips • Huge contributor to global disability • A major cause of hip and knee replacements Primary Risk Factors: - Age - Genetics - Inflammation - Overuse / Disuse - Overweight: increased mechanical loading stress - Obesity: pro-inflammatory state  Promotes joint degeneration OSTEOARTHRITIS - PATHOPHYSIOLOGY Articular cartilage: Structural damage and erosion due to mechanical stress, inflammation Proteolytic enzymes are released from chondrocytes which further degrades cartilage Bone becomes exposed and damaged (cracks form) Cysts and osteophytes develop Pieces of osteophytes and damaged cartilage break off and float around in synovial cavity Degeneration of articular cartilage  Friction & Damage  Inflammation  Pain OSTEOARTHRITIS Signs & Symptoms • • • • • • Pain with movement and weight bearing Swelling Limited ROM (stiffness) Crepitus may be heard Deformity Can affect other joints, body alignment Diagnosis • No systemic signs or changes in blood levels • May see inflammation or changes in the joint with XRAY (E.g. joint space narrowing, osteophytes, bone cysts) Radiographic imaging of OA. Normal knee (left image) and osteoarthritis Knee (right image) (lateral view). OA images display joint space narrowing, morphological changes of the joint and surrounding bone structures and importantly a thinner cartilage layer. Sacitharan P. K. (2019). Ageing and Osteoarthritis. Sub-cellular biochemistry, 91, 123–159. https://doi.org/10.1007/978-981-13-3681-2_6 OSTEOARTHRITIS TREATMENT REGIME Sacitharan P. K. (2019). Ageing and Osteoarthritis. Sub-cellular biochemistry, 91, 123–159. https://doi.org/10.1007/978-981-13-3681-2_6 EXERCISE FOR PREVENTION & TREATMENT OF OA • Low impact exercise • Flexibility / Strength / Aerobic • Emphasize importance of muscle strengthening exercises • 3 x per week is ideal for experiencing quick effective pain relief • Analgesic benefits seen in just a few weeks, even in >75YO NO CLASS ON THURSDAY • Asynchronous Activity: case study 1 • Journal club prep.