Salter-Harris Fracture Classifications

The Salter-Harris fracture is a common injury in children, involving the growth plates of the long bones. Approximately 15% to 30% of all childhood fractures are growth plate fractures and are common in the lower leg bones (tibia and fibula). It is important to detect these fractures as they may affect the growth of the bone if not treated properly.

There are five types of Salter-Harris fractures. The higher the type number, the more complications associated with the fracture.

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Type I

Type I

Only 5% of fractures are Type I. It may be difficult to diagnose unless there is obvious displacement and sometimes the diagnosis is a clinical one. Type I fractures occur though the weak zone of the provisional calcification and are known for their fast healing and rare complication rate.

Type II:

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Type II

Approximately 75% of fractures are type II. These fractures occur at the physis (growth plate) and metaphysis – and when the corner of the metaphysis separates (Thurston-Holland Sign). The fragment usually stays with the epiphysis while the rest of the metaphysis will displace. Typically, healing is fast and growth is usually okay; however, distal femur fractures may result in growth deformity.

 

Type III:

10% of fractures are Type III, which are defined as fractures of the growth plate and epiphysis, or even a split of the epiphysis. The fractures extend into the articular surface of the bone and will require reduction of the joint. In distal femur fractures it may result in a growth deformity.

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Type III

Type IV:

About 10% of fractures are Type IV fractures—which pass through the epiphysis, physis (growth plate), and the metaphysis. Type IV fractures can cause complications such as growth disturbance and angular deformity.

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Type IV

Type V:

Type V fractures are uncommon, only occurring about 5% of the time. In type V fractures, compression or a crush injury of the growth plate takes place. This fracture has no association with the epiphysis or metaphysis and an initial diagnosis may be difficult. Despite being uncommon, these fractures have the highest incidence of growth deformity and disturbance.

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Type V

Unbelievable Bacteria

One of the ways bacteria enters the body is through an open wound. When an open wound goes straight down to a fractured bone it is called and open fracture. When bacteria gains access to the deeper tissue beneath the open wound, the tissues become contaminated. Preoperative and prophylactic antibiotics are given to the patient to help decrease the infection rate with the hope of killing the bacteria in the contaminated field.

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Additionally, a special treatment is done during an open fracture to further help prevent infection. This treatment consists of irrigating and washing the wound, as well as debridement of the dead tissue. Once the tissue has been adequately cleaned, the fracture needs to be reduced and stabilized. Three different ways to stabilize the fracture is with a plate, a rod, or an external fixator. The open wound is either left open for a variable amount of time and it is closed later on. At the time of wound closure, a skin graft will be needed. To promote healing of the fracture a bone graft will be needed usually four to six weeks after the injury.

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A bone graft is obtained from the pelvis as the pelvis has a large reserve of bone that can be utilized. The bone that is harvested is cut into pieces and then added to the fracture where needed. Despite the best care, a certain percentage of open fracture injuries will become infected. When the tissues become infected by bacteria, white blood cells are attracted to the infected site where the bacteria are multiplying and causing inflammation.

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Bacteria multiply by replicating their DNA and then dividing into two identical bacterial cells. Due to the doubling of bacterial cells, the population of the bacteria grows rapidly. Once at the site of infection, the white blood cells begin to ingest the bacteria. These bacteria however, may survive and multiply within the white blood cells, causing the cells the burst. When this occurs, the bacteria is then released back into the tissues.

Other types of bacteria can also produce a thick capsule that prevents them from being engulfed. Engulfed bacteria may also produce toxins used to destroy cells that try to attack them. Bacteria can also hide in dead bone or bone cells. When this happens, antibiotics and white blood cells are unable to reach the bacteria, since the dead bone has no blood supply. In addition to the bacteria hiding in the bone, the bacteria grow rapidly.

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During this growth period, the bacteria communicate with one another through a process known as quorum sensing. Quorum sensing is the use of a chemical signals from one bacteria to another. As the bacterial population grows, the concentration of the chemical signal. Once the concentration of the chemical signal reaches a certain threshold, the bacteria then begin their attack. The bacteria will attack the tissues causing it to break down and die which can lead to an abscess formation. The abscess must be drained and evacuated, followed by antibiotic treatment.

bacteria communuity

Antibiotics can kill bacteria in several different ways. One way is by disrupting the cell wall which ruptures the bacteria. Another way, is by preventing DNA replication by blocking the unwinding of the DNA. A third way is by inhibiting the ribosomes from making proteins needed for the cellular structure and function. The last way is by blocking the enzymes that produce folate. Folate is needed for DNA synthesis, and without it the cell will die.

When hardware is used to stabilize the fracture, the story can become much more complex.

 

Finger Fractures

Fractures to the fingers and hands are common. Mallet finger is a deformity caused from a blow to the finger at the DIP joint. Patient is unable to straighten the DIP due to avulsion injury.

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Most often mallet finger injuries can be treated without surgery. Treatment is given by applying a splint to immobilize the fingertip in extension. Movement should be allowed in the PIP joint. Surgery may be necessary if more than 50% of the joint is involved or there is subluxation of the joint to restore the function of the extensor tendon.

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Middle and proximal phalangeal fractures:

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The normal relaxed cascade of the hand should form a straight alignment of the fingers.  When holding a relaxed cascade, the fingers should normally point towards the region of the scaphoid. Malrotation of the finger will cause the affected finger to deviate from its normal rotational direction.

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Treatment:

If there is no rotational deformity, the finger is treated by buddy taping the injured finger to the adjacent normal finger for 2-3 weeks. If rotational deformity is present, a digital block is given and the fracture is reduced in a volar splint. The MCP is held in 70 degrees of flexion for proximal phalanx fractures for 2-3 weeks. The splint holds the DIP and PIP in 0 degrees extension in middle phalanx fractures. Then buddy tape for additional 2 weeks.

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Metacarpal fractures:

The wrist should be immobilized in 20 degrees extension and the MCP in 60-70 degrees of flexion.

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The fingers should be kept free in order to check for rotation. Finger fractures means stiffness of the fingers.

Indication for surgery:

  • Rotational deformity
  • Open fracture
  • Multiple unstable fractures
  • Significant angulation or deformity.
  • Articular displacement
  • Metacarpal shortening especially with the middle and index fingers.

If the fracture is displaced or unstable, closed reduction and K-wire is an option for fixation.

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Plating is another option for fixation however it is rare.

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In phalanx fractures treated by ORIF, adhesions of the extensor tendon may occur. Patient may have decreased range of motion of the PIP which is called extrinsic tightness.

The patient will have greater passive PIP flexion with MP extension compared to when MP is flexed.

 

Osteoporosis

Osteoporosis is a decrease in bone strength. The strength of the bone depends on mineral density and bone quality. Osteoporotic bone is at risk of fracture at the hip, wrist and spine.

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If fracture of the vertebral spine occurs, the patient will have a fivefold increased risk for having a second vertebral fracture or hip fracture. A second vertebral fracture means you may have more compression fractures in the future.

With one hip fracture, there will be a tenfold increase of another hip fracture occurring. Men with hip fractures have a higher mortality rate than women.

Lifetime risk of fractures of the hip, spine and wrist is 40 %. The decrease of bone strength and bone mass clearly predicts fracture risk.

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Osteoporosis affects 45% of women aged 50 or older. There is some correlation between osteoporotic fracture and risk of death. This is logical since 25% of patients with hip fracture die within one year. The lifetime risk is high with senile osteoporosis. There are about million osteoporosis related fractures that occur per year.

Men and women both begin to start “spending” or losing bone at a certain point in their lives. Banking or building up of bone during youth has benefits during the later years. Most individuals obtain their peak bone mass between ages of 16 and 25 years. Men begin to lose bone mass after the age of 25 years at a rate of 0.3% per year. Women begin to lose bone at a rate of 0.5% per year. After menopause there is an accelerated rate of bone loss at the rate of 2-3% of total bone loss per year for about 10 years.

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Osteoporosis has bone mineralization but abnormal osteoclast function. There are two types of osteoporosis:

  1. Type I: postmenopausal which occurs 15-20 years after menopause. It has increased risk of vertebral and wrist fractures. It is due to estrogen deficiency.
  2. Type II: senile which occurs in men and women over the age of 70 years. Vertebral and hip fractures are a risk. It occurs more in females than males with a ratio 2:1. It is due to aging and long term calcium deficiency.

20-25% of elderly patients could die within one year suffering of a hip fracture.

osteoporosis4.pngRisk factors for osteoporosis include: thin, north European descent, people who live sedentary lifestyles, smoker and drinkers, and anti-seizure medications as phenytoin (Dilantin) and phenobarbital.

The bone mineral density is measured by T- score which is relative to normal age, young, matched control (25 year old women) and Z-score which is relative to similar aged patients.

How is osteoporosis measured? It is measured by DEXA scan at the hip through the T –score. DEXA scan is important in predicting fracture risk.osteoporosis5.png

Lab findings as albumin, calcium, phosphate, vitamin D, parathyroid hormone and bone specific alkaline phosphatase are usually normal.

Vitamin D levels are low in about 70 % of patients with fracture. Vitamin D absorbs calcium from the intestines. With aging, the stomach acidity decreases and the calcium absorption decreases and vitamin D requirements increase. Elderly need more vitamins D to absorb the same amount of calcium.

Treatment of osteoporosis include: bisphosphonates, Denosumab and calcitonin. Bone stimulation can be achieved by parathyroid hormone, calcium and vitamin D.

When to initiate therapy? If T-score is less than -2 with no risk factors, if T-score is less than -1.5 with at least one risk factor as prior vertebral fracture or hip fracture.

What decides if you develop osteoporosis or not? Your savings: you can control this by adding more bone when you are young before the age of 25 years. You begin spending your bone after 25 years.