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.

Hamate Fractures

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Fractures of the hamate bone are rare, difficult to diagnose, and routine x-rays may not show the fracture. Hamate fractures are classified as either a hook fracture or as a body fracture.

Hamate hook fractures are usually seen in individuals who participate in sports which involve a racquet, baseball bat, or from swinging a golf club.

Swinging of the golf club may cause a hook fracture of the Hamate bone. Missing the fracture can lead to persistent pain from nonunion.

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Hamate body fractures are associated with axial force trauma, such as a fist striking a hard object, a fall, or from crushing injuries. It may also be accompanied by 4th and 5th metacarpal subluxation. Coronal fractures are the most common type of Hamate body fractures.

There are three types of coronal fractures; Type A (large piece), Type B (moderate piece) and Type C (avulsion). Make sure to watch out for subluxation of the joint due to pull from the Extensor Carpi Ulnaris.

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Hook fractures of the Hamate are best seen by carpal tunnel or supination x-ray views. For hamate fractures, CT scan is the best study. A 30° pronated view is helpful for body fractures.

Clinical Evaluation

Pain will be present, especially with axial loading of the ring and little finger or by grasping an object. The patient will have dismissed grip strength. They may have ulnar and median nerve neuropathy symptoms. The most common findings are pain and tenderness on the ulnar side of the wrist, distal to the wrist joint.

The pull test has been recently described. This is when the palm of the hand is placed into supination, the wrist is in full ulnar deviation, and the fingers of the patient should be flexed. The examiner pulls on the ulnar two digits with the patient resisting the pull. A positive test with pain in the area of the hook indicates a fractures hook of hamate injury. Pain may also be felt due to compression of the ulnar nerve in the Guyon Canal.

Treatment                        

Early immobilization for acute fractures with short arm splint for 6 weeks will be used to avoid a nonunion. For symptomatic nonunion, excision of the fracture fragment will be needed.

Types A and B require open reduction and internal fixation, in addition to stabilization of the joint if needed. Type C requires closed reduction and percutaneous pinning of the fragment for stabilization of the joint. If a closed reduction of the joint is not adequate, open reduction and stabilization of the joint should be done. A displaced fragment with subluxation requires reduction of the joint and stabilization of the joint with K-wires or fixation of the fragment.

When a 4th or 5th carpometacarpal dislocation occurs, one should make special effort to find a coronal fracture of the hamate.

 

 

 

Ankle Fractures – Danis Weber Classification

The more proximal fibular fractures indicate a risk of syndesmotic disruption and ankle instability.

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Type A is an internal rotation and adduction injury. The fracture of the fibular is below the level of the tibial plafond. It is usually an avulsion injury from supination of the foot. It may be associated with an oblique or vertical medial malleolus fractures. Syndesmotic disruption is rare, but it can occur.

Type B is an oblique or spiral fractures of the fibula near or at the level of syndesmosis. This is an external rotation injury. It may be an associated injury to the medial structures of the posterior malleolus. Occurrence of a syndesmotic injury is 50%.

Type C is an abduction injury. The fracture of the fibula is above the level of syndesmosis. Syndesmosis disruption always occurs. In almost all cases there is an associated medial injury. It includes a maisonneuve fracture pronation abduction or pronation external rotation.

Femoral Neck Fractures

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Stress fractures of the femoral neck are most commonly seen in athletes, such as runners. Females are more common than males to experience stress fractures of the femoral neck. Beware of female runners with pain in the groin and normal x-rays.

Clinical findings

The clinical findings for stress fractures of the femoral neck include groin pain, pain with weight bearing activity and negative x-ray in about 2/3 of the patients. An MRI is the best study when diagnosing stress fractures of the femoral neck. Exclude other causes of hip pain such as transient osteoporosis and avascular necrosis.

Types of Stress Fractures

Compression fractures

Compression fractures are a callus at the inferior aspect of the femoral neck. If the fracture involves less than 50% of the femoral neck, it can be treated with non-weight-bearing and crutches, as well as restricted activity. If the fracture involves more than 50% of the femoral neck, it should be treated with screw fixation.

Tension Fracture

A tension fracture is a fracture at the superior aspect of the femoral neck. The adult bone is weak in tension and with tension the fracture will propagate. Treatment should be done with screw fixation.

Displaced Fracture

A displaced fracture will have a bad prognosis especially with younger patients. There is risk of avascular necrosis and nonunion with displaced fractures. This is considered to be an emergency in younger patients. Perform a reduction and screw fixation for treatment of these fractures. It is necessary to obtain an MRI to rule out a stress fracture in elderly patients with groin pain and a normal x-ray. Use a prosthesis in the elderly.