Avascular Necrosis of the Shoulder

Avascular necrosis is death of a segment of bone. AVN may affect the proximal humerus due to interruption of the blood supply. The ascending branch of the anterior humeral circumflex artery runs in the lateral bicipital groove and then becomes the arcuate artery. The other artery that is important to the blood supply is the posterior humeral circumflex artery.

avascccc

There are several risk factors for AVN including: Alcohol, Systemic Lupus Erythematosus, infection, trauma, and steroid use. 5-25% of AVN cases are due to steroid usage. Steroids increase the serum lipids in the blood which may precipitate fat embolism into the humeral head blood vessels.

posttrauma

proximal humeral pain

Progressive collapse of the humeral head occurs due to bone death, reabsorption, remodeling, micro fractures and final collapse with joint changes and arthritis. Symptoms include: shoulder pain, weakness, crepitus, and a decreased range of motion. Symptoms are gradual and insidious with delay in the diagnosis and treatment. The patient usually has a history of risk factors.

osteomri

In regards to imagining, x-rays will show the best in the neutral rotation AP view. AVN located on the superior middle part of the humeral head just deep to the articular cartilage. If the crescent sign is seen, this is an indicator of collapse. An MRI is going to be the best imaging study. A patient with AVN of the humerus should have a hip radiograph. If the x-ray is negative and the patient has hip pain, you should obtain an MRI of the hip. It is recommended that a patient with osteonecrosis at the site of the shoulder should undergo an MRI of the hip to rule out asymptomatic osteonecrosis of the hip. You may also need to do an x-ray of the knee. AVN may involve three or more anatomic sites (multifocal osteonecrosis).

Treatment typically consists of:

  • Physical Therapy
  • NSAIDS
  • Core decompression for Stage I and Stage II
  • Resurfacing for Stage III
  • Hemiarthroplasty for Stage III and Stage IV
  • Total shoulder surgery for Stage V
    • Advanced disease
    • The results of total shoulder are inferior to patients with osteoarthritis

 

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Tarsal Coalition

Tarsal coalition is a congenital anomaly in which the tarsal bones fuse together, leading to a rigid flat foot, foot pain, and multiple ankle sprains. There are two types of tarsal coalition. The first is known as a Talocalcaneal Coalition, which is a coalition between the talus and the calcaneus. The second is referred to as a calcaneonavicular coalition which is a coalition between the calcaneus and the navicular. When talocalcaneal coalition occurs, it usually happens around 12-15 years of age. The calcaneonavicular coalition presents at an earlier age. About 50% of coalitions are bilateral, and around 20% have multiple coalitions in the same foot. Coalition may be fibrous, cartilaginous, or bony and occurs due to failure of segmentation. It could be associated with fibular hemimelia or Apert’s syndrome.

tarsal anatomy

Symptoms typically consist of patient’s complaining of a painful foot, a history of repeated ankle sprains, and a flat foot deformity. Tarsal coalition may result in a peroneal spastic flat foot. During the physical examination, the physician may find hindfoot valgus. On toe standing, the arch does not reconstitute and heel cord contracture may also be evident during the exam. Furthermore, there may be restriction in the subtalar joint’s range of motion. It is important to check both feet as the condition may be bilateral.

hindfoot

The best imaging study is a CT scan. It can determine the size and location of the coalition. And MRI is also useful in detecting a fibrous or cartilaginous coalition. AP, Lateral, and Oblique view x-rays should be ordered. On a lateral view x-ray, the Calcaneonavicular Coalition can be identified by the “anteater nose sign” and the elongation of the anterior calcaneal process.

ant

A lateral view of a Talocalcaneal Coalition may show talar beaking which is a traction spur that occurs due to the limited motion of the subtalar joint. Additionally, the C sign may be seen which is a radiological sign outlining the talar dome and the sustentaculum. A 45° oblique view is the best for showing calcaneonavicular coalitions.

45oblique

Nonoperative treatment usually consists of anti-inflammatory drugs, modified activities, or the use of a brace or cast. Surgical treatment for the calcaneonavicular coalition usually consists of resection with an interposition of the extensor digitorum brevis muscle or a fat graft no matter the size of the coalition. Similarly, Talocalcaneal coalitions that involve less than 50% of the subtalar joint are also resected. A triple arthrodesis procedure is performed for large coalitions, failed resections, or advanced conditions.

Flail Chest

Flail Chest—Everything You Need to Know

In flail chest, three or more ribs are involved in segmental fractures. A segment of the rib cage breaks and then becomes separated or detached from the chest well. It usually requires a significant amount of violent force in order for the ribs to break in this way. Due to the nature of this injury, flail chest could be a life threatening condition.

flail

The fractured segment will sink into the chest with inspiration and expand out of the chest wall with expiration opposite to the normal chest wall mechanics. The segmented rib fractures work independently. If the segmented section moves right, then the rest of the ribs move left, and vice versa. The flail chest moves in the opposite direction of the chest wall. The fractured segment goes in while the rest of the chest goes out—this is called paradoxical breathing.

There may be a pulmonary contusion associated with the flail chest fracture segment, and this contusion could be more significant than the flail segment. There may also be a noticeable chest wall deformity with the presence of air in the subcutaneous tissue (crepitus). Trauma to the chest usually causes scapular fractures or a clavicle fracture.

Symptoms of Flail Chest:

  • Patient will have chest pain and shortness of breath
  • Paradoxical movement of the flail segment
    • The constant movement of the ribs is very painful
    • The broken rib may puncture the lung and cause pneumothorax

pneumo

Images

On an x-ray, it is difficult to see if the fractures are displaced or nondisplaced. A CT scan is probably the best method for visualizing these fractures.

The prognosis varies and it depends on the severity of the condition, however, the death rate ranges between 10-25% usually depending on the pulmonary injury. About 8% of patients who are admitted to the hospital with fractured ribs will have a flail chest.

Treatment

If there is no respiratory compromise and no flail chest segment, observation of the patient will be done. It is important to follow advanced trauma life support (ATLS) principles.

  • Airway
  • Breathing
  • Circulation

The patient’s pain will need to be managed—usually with intercostal nerve blocks. It is essential to avoid the suppression of breathing and if necessary, give the patient positive pressure ventilation (a chest tube if needed).

Surgery

Surgery may help in reducing the duration of the ventilator support and aid in the pulmonary function. The patient will need aggressive pulmonary toilet and physiotherapy.

An open reduction and internal fixation should be done when there is severe pain and displaced ribs, when there is a flail chest segment (three or more consecutive fractured ribs with segmental injury), the rib fractures are associated with failure to wean the patient off of ventilation, and/or when there are open rib fractures.  Usually a plate and screw system is used in addition to early range of motion of the shoulders.

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.

open fx bacteria

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.

skin graft

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.

multiple bacteria

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.

engulf

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.