common joint injuries

Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 43

Disorders of the Skeletal System:

Trauma, Infections, Neoplasms, and

Childhood Disorders

Chapter 43

Disorders of the Skeletal System:

Trauma, Infections, Neoplasms, and

Childhood Disorders


Common Joint InjuriesCommon Joint Injuries

• Injuries to muscles: strains

• Injuries to ligaments: sprains, ruptures

• Injuries to tendons: rotator cuff injuries

• Injuries to bone surfaces

– Joint dislocations

– Patellar dislocation

– Loose bodies

– Meniscus injuries

– Chondromalacia


Common Joint Injuries (cont.)Common Joint Injuries (cont.)

• Rotator cuff injuries

– Clavicle fractures

– Dislocations

– Bursa damage

– Torn tendons

• Hip injuries

– Dislocation

– Fracture


Knee InjuriesKnee Injuries

• Meniscus injury

• Patellar dislocation

• Chondromalacia


Question Question

Tell whether the following statement is true or false.

Chondromalacia is the most common type of knee injury.


Answer Answer

False

The most common knee injuries are tear of the ACL (anterior cruciate ligament), caused by hyperextension, and damage to the meniscus.


FracturesFractures

• Transverse

• Oblique

• Spiral

• Comminuted

• Segmental

• Butterfly

• Impacted


Bone HealingBone Healing• Hematoma forms and fibrin network fills it

• Cells grow along fibrin meshwork to form new tissue

• Calcium salts deposited in new tissue

• New tissue remodeled into normal shape


Question Question

Which of the following represents the correct sequence of bone healing?

a. Hematoma – cartilage – bone

b. Hematome – elastin – fibrocartilage

c. Cartilage – spongy bone – compact bone

d. Hemangioma – spongy bone – compact bone


Answer Answer

a. Hematoma – cartilage – bone

Following a fracture, a hematoma forms; collagen and cartilage are deposited (soft callus); bone tissue is ossified (hard callus).


Complications Resulting from Soft Tissue InjuryComplications Resulting from Soft Tissue Injury

• Skin injury: fracture blisters

• Muscle injury and swelling: compartment syndrome

• Nerve injury: reflex sympathetic dystrophy

• Adipose tissue or bone marrow: fat emboli


OsteomyelitisOsteomyelitis

• Infection of bone

– Direct contamination

– Contamination through blood (hematogenous)

º Miliary tuberculosis

– Contamination from skin lesions


Hematogenous OsteomyelitisHematogenous Osteomyelitis

• In children:

– Affects long bones

– Purulent exudate inside bone

– Damages arteries to bone

– May penetrate skin or involve joints

• In adults:

– In vertebrae, sternoclavicular and sacroiliac joints, or pubic symphysis

– Tends to affect joint space


Chronic OsteomyelitisChronic Osteomyelitis

• Areas of dead bone develop (S)

• Are surrounded by new bone (IV)


OsteonecrosisOsteonecrosis

• Caused by ischemia to bone due to:

– Bone injury

– Thrombosis or embolism

– Vessel injury

– Compartment syndrome inside bone (increased intraosseous pressure)

– Corticosteroid associated


Question Question

Which type of bone disorder is associated with thrombus formation or embolus?

a. Hematogenous osteomyelitis

b. Chronic osteomyelitis

c. Osteonecrosis

d. Osteoinfarction


Answer Answer

c. Osteonecrosis

Bone has an extensive blood supply (remember, it can’t rely on diffusion of nutrients and gases like cartilage can). When blood flow to an area of osseous tissue is disrupted because of a clot/thrombus or an embolus (a clot that has broken off and traveled), the tissue dies (necrosis).


Benign Bone TumorsBenign Bone Tumors

• Osteoma: small bony tumor on bone surface

• Chondroma: tumor made of cartilage

• Osteochondroma: cartilage-capped tumor with bony stalk

• Osteoclastoma: giant cell tumor

– May invade bone and cause bone destruction


Malignant Bone TumorsMalignant Bone Tumors

• Osteosarcoma

– Most common primary malignant bone tumor

– Tends to appear in areas with the fastest bone growth

• Ewing sarcoma

• Chondrosarcoma

– Malignant tumor of cartilage

• Metastases

– Most common malignancies found in bone


Manifestations of CancerManifestations of Cancer

• Changes in organ function (organ damage, inflammation, and failure): pathologic fracture

• Local effects of tumors (e.g., compression of nerves or veins, stretching of periosteum): pain and weakness

• Nonspecific signs of tissue breakdown (e.g., protein wasting, bone breakdown): calcium release, hypercalcemia


Question Question

Tell whether the following statement is true or false.

Bone cancer is more likely to result in the release of PTH than the release of calcitonin.


Answer Answer

False

As bone tissue deteriorates/breaks down, calcium is released into the blood (hypercalcemia). The hormone released in response to hypercalcemia is calcitonin (it inhibits osteoclasts). PTH is released in response to hypocalcemia.


ScenarioScenario

Mr. K had lung cancer and received chemotherapy…

• He is suffering from chronic back pain and weakness, and he has trouble moving his hands and grasping heavy objects

• His blood calcium is elevated, and CT scans show lesions in his thoracic spine

Question

• What are two possible explanations for his weakness?


Variations in Normal Growth and DevelopmentVariations in Normal Growth and Development

• Torsional deformities

– In-toeing and out-toeing

– Internal and external tibial torsion

– Internal and external femoral torsion

• Genu varum and genu valgum


Hereditary and Congenital DeformitiesHereditary and Congenital Deformities

• Congenital dysplasia of the hip

• Foot deformities (clubfoot)

– Talipes varus: foot inverted at heel

– Talipes valgus: foot everted at heel

– Talipes equinus: plantarflexion, toes lower than heel

– Talipes calcaneus: dorsiflexion, heel below toes


Abnormal Bone FormationAbnormal Bone Formation

• Osteogenesis imperfecta

– Mutations in genes for collagen

• Juvenile osteochondrosis

– Osteonecrotic

º Local degeneration of ossification centers followed by disordered regeneration

– Abnormal ossification of cartilaginous tissue


ScoliosisScoliosis

• Postural

• Structural

– Congenital

– Neuromuscular

– Idiopathic

common joint injuries

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