Osteoporosis. Dr. C. C. Visser. MBChB MMed (Med Phys) Diploma Musculoskeletal Medicine (UK) Member: Society of Orthopaedic Medicine (UK)

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1 Osteoporosis Dr. C. C. Visser MBChB MMed (Med Phys) Diploma Musculoskeletal Medicine (UK) Member: Society of Orthopaedic Medicine (UK)

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4 Effect of age on trabecular bone. Fatfree dry bone cylinders obtained from the iliac crest of a 20- (a) and a 60- year-old person (b).

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12 Dowager s hump. Marked thoracic kyphosis due to multiple osteoporotic fractures in elderly woman.

13 Dowager s hump. Marked thoracic kyphosis due to multiple osteoporotic fractures in elderly woman with corresponding radiograph.

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16 Diagnosis

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20 Changes in vertebral shape due to osteoporosis. Normal vertebra (1), wedge fracture (2), biconcave or fish vertebra (3), and a compression fracture (4).

21 Osteoporotic fracture. Radiograph illustrating radiolucency, Schmorl s node, wedge and compression fractures

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24 Treatment

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30 Stress Fractures

31 Stress Fractures Partial/complete fracture of cortical/cancellous bone due to its inability to withstand rhythmic nonviolent stress applied repeatedly in a submaximal manner Often associated with muscle overloading / fatigue reduction in shock absorption redistribution of forces to the bone 5 % of all sports injuries (Recreational and well trained athletes): 75% are tibial / tarsal

32 Types of Stress Fracture Fatigue stress #: abnormal repetitive load applied to normal bone Insuffiency stress #: normal stressing of abnormal bone (osteoporosis/osteomalacia) Combinations can exist

33 Predisposing factors Risk factors for osteoporosis Female Amenorrhoea Poor diet Caucasian Poor fitness with rapid progression in training Biomechanical abnormalities esp excessive pronation/foot rigidity

34 Pathology Normally equilibrium between osteoblastic and osteoclastic activity Controlled loading of bone: increase in osteoblastic activity giving greater bone density and strenght (stress reaction) Repeated overloading of bone: increase in osteoclastic activity with weakening and eventually failure of bone (stress #)

35 Bone response to stress Heals or Forms localized area of mature periosteal and endosteal hyperostosis (cortical hypertrophy = stress reaction) if bone response is greater than demands on bone or Develops stress # Stress on bone leads to progressive deformity If deformity within elastic range, bone returns to original configuration when deforming force relaxes If stressed beyond elastic range, permanent deformity due to microfractures If continued stress, number of stress # increases and progresses leading to structural failure (stress#)

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37 Common sites Sesamoids: Medial-middle to distal: standing, running, football Metatarsal 2 nd, 3 rd -shaft: running, marching, ballet, skating 5 th -distal to tuberosity:running, basketball Navicular central third-dorsal and proximal:basketball, running Calcaneus posterior-dorsal:running, jumping, marching

38 Tibia Posterior-junction of proximal and middle/junction of distal and middle thirds: running, marching, aerobics, ballet, basketball Anterior-midshaft: ballet, basketball, running Fibula Proximal: jumping, parachuting Supramalleolar: running, marching Patella midpole: jumping, basketball, hurdling Femur Neck: running, long distance running, ballet Shaft-junction proximal and middle thirds: long distance running, ballet

39 Pelvis junction of pubis and ischium: long distance running Sacrum proximal: running, aerobics Spine (lumbar): ballet, gymnastics, running, weight lifting Ribs 1 st : backpacking, weight lifting, pitching Lower ribs: golf, rowing

40 Clavicle medial: carrying heavy weights Scapula coracoid: golf, shooting Humerus shaft: pitching, tennis, wrestling, shotputting Radius shaft: pitching Ulna shaft: shoveling, rowing, pitching, body building, wheelchair athletics Hamate hook: golf, tennis, batting Scaphoid waist: shotputting, gymnastics

41 Symptoms and Signs Severe pain in region: aggravated by activity, initially relieved by rest but later not any more Tenderness over site Swelling and increased warmth if # in superficial bone Palpable localized periosteal thickening in chronic cases Loading bone will cause pain eg hopping on injured leg Fulcrum test of long bones: pressure on bone away from # site will cause pain at the site

42 Investigations: X-ray s 25% accurate early on Changes occur between 2 weeks and 3 months Cancellous bone eg calcaneus, long bone ends: Linear radiodense area orientated perpendicularly to the trabeculae (=collapsed trabeculae, osteoblastic activity, endosteal callus) Cortical bone: Radiolucent line within an area of cortical hyperostosis Line either perpendicular or parallel to the long axis of the bone Not always visible if the surrounding localised stress response is massive: try overpenetrated X-rays, tomography, CT, MRI

43 Stress reaction with cortical hyperostosis

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49 Stress fractures of the fibula in RA. Radiography of the right ankle and foot shows severe osteoporosis, rheumatoid deformity with a valgus hindfoot and a healed stress fracture of the lower part of the fibula with extensive callous formation.

50 Stress fracture of the fibula in RA. Radiography of the knee joint shows erosive RA resulting in a valgus deformity of the joint and extensive destruction of the lateral compartment. The resulting mechanical stress has led to an oblique fracture in the upper part of the fibula.

51 Investigations: Tc-Bone scan Nearly 100 % diagnostic May be positive within 6-72 h after onset of pain Triple phase bone scan (blood flow, soft tissue hyperaemia, bone turnover): old vs new # partial vs complete # soft tissue lesions vs bony lesions

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53 Investigations: MRI and CT MRI: nonspecific and too expensive CT: Bone marrow oedema Perisoteal reactiobn Fracture (not always) Nonunion of tarsal stress fractures: Initially ill-defined area of mildly increased cortical activity Spreads into medulla and is highly active Sreads to the opposite cortex and becomes intensely active Seldom required in most stress fractures

54 Treatment Cease all activity involving injured bone Weightbearing bones: partial/nonweight bearing Immobilisation seldom required except in tarsal # Certain femur neck # may require internal fixation

55 Complications Complete fracture, especially Femoral neck : medial aspect just proximal to lesser trochanter linear radiodense region orientated perpendicularly to long axis of bone ie cortical pattern Navicular: # in saggital plane at junction of middle and lateral thirds difficult to see on X-ray, do Tc scan/ct/mri Can lead to nonunion / ischaemic necrosis of lateral fragment Delayed union/nonunion: sclerosis bordering fracture margins partially or completely Flat/irregular bones like ischium & ribs, navicular, ant cortex of mid tibia, base of 5 th MT distal to the tuberosity Contralateral injuries

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