Educational

1. PATHOPHYSIOLOGY OF
SKELETAL INJURIES
HAFSA SYED

2. Introduction
■ Skeletal injuries are common in sport, especially in
contact sports, such as football and rugby, and in
individual sports such as skiing and gymnastics.
■ The skeleton can be divided into two subgroups:
■ 1. Axial skeleton – bones of the skull, vertebral column,
ribs and sternum
■ 2. Appendicular skeleton – bones of the upper and lower
limbs.

3. ■ Bones function as:
■ Protectors of vital organs – provides mechanical protection for
most of the body’s internal organs, thereby reducing the risk of
injury to them
■ Supportive structures – the skeleton is the framework of the body
it provides attachment for skeletal muscles
■ Levers – the skeleton assists with movement Reservoirs for
calcium and phosphorus – storage for minerals (calcium and
phosphorus), which are released when needed into the blood
■ Blood producing cells – develops red blood cells in the bone
marrow.

4. Bone structure
■ There are primarily three types of bone, namely: woven, compact and
cancellous.
■ Woven bone is normally remodelled and replaced with either compact or
cancellous bone. Woven bone is found during embryonic development,
during fracture healing (callus formation).
■ Compact bone is the outer structure and provides mechanical strength,
while cancellous bone forms the inner structure and its function is the
metabolic unit of the bone.
■ Classification of bones
■ Bones are usually classified according to their shape.

6. Bone formation and growth
■ 1. Osteoblasts (bone forming cells)
■ 2. Osteoclasts (bone eating cells).
■ 3. Osteocytes (cells of the matrix) – found in mature adult
bone.

7. Cartilage
■ Cartilage is a non-vascular connective tissue that is divided,
according to its minute structure, into: hyaline cartilage (articular)
– covers joint surfaces fibrocartilage – knee meniscus, vertebral
discs elastic cartilage – outer ear.
■ These different forms of cartilage are distinguished by their
structure, elasticity, and strength.
■ In general, cartilage is a tough, fibrous and blood vessel-free
connective tissue that forms flexible linkages, supporting
structures and acts as a shock absorber in joints such as the knee.

8. Osteoarthritis (OA)
■ Osteoarthritis (OA) is the most common form of arthritis,
which is a leading cause of physical disability, increased
healthcare usage and impaired quality of life .The term OA
also applies particularly to the degeneration and excessive
wear of cartilage. This condition develops and progresses
with an increase in age.
■ Sport activities that appear to increase the risk for OA include
those that demand high-intensity, acute, direct joint impact as
a result of contact with other participants, playing surfaces or
equipment

9. Common skeletal injuries
■ Fractures are potentially serious injuries, damaging
■ not only the bone but also the soft tissue in the surrounding
■ Area bone fracture can be very painful, due to
■ (1) the breaking in the continuity of the periosteum;
■ (2) oedema of nearby soft tissues, caused by bleeding of torn
periosteal blood vessels, evoking pressure pain; and
■ (3) spasms in muscles trying to hold bone fragments in place.

10. Clinical features of a fracture
■ pain
■ deformity
■ oedema
■ muscle spasm
■ abnormal movements
■ loss of function
■ shock
■ limitation of joint movement

11. ■ Stress fractures occur in normal and abnormal bones that
have been subjected to repeated traumas
■ These fractures occur in weight-bearing and non-weight
bearing bones. There are two general types of stress
fractures, insufficiency fracture and a fatigue fracture.
Insufficiency fracture results from normal stress applied to
abnormal bone that is weakened by an underlying disorder
such as osteoporosis, rheumatoid arthritis, osteomalacia.
■ Fatigue fractures occur when normal bones are subjected to
increased loads and repetitive stresses.

14. Osteoporosis
■ Osteopenia is not an injury but if left untreated can lead
to the development of osteoporosis.
■ Osteoporosis is three times more common in women
than in men, partly because women have a lower peak
bone mass and partly because of the hormonal changes
that occur at the menopause.
■ Oestrogens have an important function in preserving bone mass
during adulthood, and bone loss occurs as levels decline, usually
from about the age of 50 years.

15. The Female Athlete
■ The female triad is defined as a serious syndrome
consisting of three interrelated components:
■ 1. disordered eating
■ 2. amenorrhea
■ 3. osteoporosis

16. ■ The athletes most at risk are those participating in sports
in which success is determined by thinness and
aesthetics.
■ Results of treatments for reversing bone loss in athletes
with menstrual dysfunction, such as hormone
■ replacement

17. The osteoporosis risk factors are summarised
below:
■ female sex
■ premature menopause
■ age
■ primary or secondary amenorrhoea
■ slight body build
■ primary and secondary hypogonadism in men
■ Asian or Caucasian race
■ previous fragility fracture
■ glucocorticoid therapy
■ maternal history of hip fracture
■ low body weight

18. ■ cigarette smoking
■ excessive alcohol consumption
■ prolonged immobilisation
■ vitamin D deficiency
■ low dietary calcium intake.

19. Healing re-modelling process during
injury/rehabilitation
■ Healthy bone remodelling occurs at many simultaneous
sites throughout the body where bone is experiencing
growth, mechanical stress, microfractures or breaks.
About 20% of all bone tissue is replaced annually by the
remodelling process. The total process takes about 4–8
months, and occurs continually throughout our lives. The
healing potential of bone is influenced by a variety of
biochemical, biomechanical, cellular, hormonal and
pathological mechanisms.

20. ■ The first stage of bone healing is referred to as the inflammatory
phase (also known as the granulation stage, fracture stage or
clot phase). This stage has two parts to it: during the first part of
this stage the surviving cells are sensitised to chemical
messengers that are involved in the healing process, this stage
is completed within seven days. The second part, which lasts for
about two weeks, is the development of a clot around the
fracture site; this I not seen within stress fractures. After the clot
has been formed, granulation tissue forms within the space
between the fracture fragments. This granulation tissue then
activates macrophages. The second stage is known as the
reparative phase callous stage), and can be divided into the soft
callous and hard callous stages. During the soft callous stage
the osteoblasts and chondrocytes within the granulation tissue
begins to make cartilage and woven bone matrices. This newly
formed callus begins to mineralise after approximately a week.
This mineralization concludes with the formation of a fracture
hard callus, this callus is detectable on X-rays due to the
calcium it contains. The creation and mineralization of the callus

21. ■ The third stage is called the remodelling phase
(consolidation phase), In the remodelling phase the
process may occur over months to years and consists of
restoring the fractured bone to its normal size, shape and
strength.Adequate strength usually develops by six
months.

22. Effects on the bone healing process
Nutrition
■ Calcium plays an important role in helping attain peak bone mass during
bone development and preventing fractures in later life. The daily
recommended allowance of calcium intake is 800–1200 mg
■ Multiple factors can affect the bioactivity of calcium:
■ high-fat or high fibre diets can interfere with or decrease the activity of
calcium
■ large doses of zinc supplementation or mega doses of vitamin A can lower
calcium bioactivity
■ high protein diets can decrease calcium reserves by increasing urinary
excretion of calcium

23. ■ In addition, alcohol consumption can decrease the absorption
of calcium and various medications (heparin glucocorticoids)
can affect calcium activity. Vitamin D regulates calcium
absorption and excretion, especially when calcium intake is
low.
■ When calcium levels in the blood drop, parathyroid hormone
(PTH) is released. PTH causes calcium to be released from the
bones; this then raises the low calcium levels in the blood.
Osteoporosis may result from chronically high levels of PTH
(Groff and Gropper 2000).

24. Effect of NSAID's on fracture healing
■ Bone repair is a complex process initiated by injury and
an inflammatory response. Prostaglandins mediate
inflammation, influence the balance of bone formation
and resorption; processes that are essential for new
bone formation. NSAIDs inhibit cyclooxygenases, which
are essential for prostaglandin production (Dumont et al.
2000). It has been shown that long-term excessive use of
these medications may reduce normal bone healing.

25. Conditions that have a negative effect
■ infection
■ poor reduction (poor realignment of fracture)
■ loss of local blood supply due to injury
■ vascular injury
■ failure to make callus (metabolic abnormalities)
■ formation of scar and fat tissue instead of callus
■ poor nutrition
■ alcohol abuse
■ smoking.

26. ■THANKS