Lipoma Removal

Lipoma is the most common type of soft tissue tumor. It is a benign tumor that contains fat. Lipomas are slow growing, asymptomatic, and painless. They are typically soft and mobile with superficial swelling. If it is deep or intramuscular, it is usually large and may be firm, similar to a sarcoma. Deep lipoma is usually close to the neurovascular bundle. Most of the lipomas are superficial. Deep lipomas are infrequent and they present a problem on the diagnosis. Lipoma is rarely seen in younger patients. It is usually seen in patients older than 40 years of age and men; occasionally, lipoma occurs in multiples.

benign mature fat

Liposarcoma is a malignant tumor that arises in fat cells. This condition is usually proximal to the knee and elbow. Consider liposarcoma or any other soft tissue tumor if the tissue mass is deep, more than 5cm, and located in the thigh. An MRI will show a homogeneous signal intensity. It has the same signal as fat in the subcutaneous tissue in all pulse sequences. The fatty tumor has the same fatty appearance as the subcutaneous fat. The signal is bright on T1, dark on T2, and in STIR. Liposarcoma will be dark on T1 and bright on T2. Liposarcoma is also hot on a bone scan. Lipoma is avascular and cold on a bone scan. A marginal excision may be performed if the lipoma is painful, growing, or deep, otherwise it is observed. Recurrence is rare.

Permanent section is needed for the diagnosis after excision of the fatty tumor. Biopsy is not needed, an MRI makes the diagnosis. Histology shows mature fat, no mitosis, atypical, or pleomorphic.

 

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.

 

Stiff Knee

Extension contracture of the knee can result from different causes, but it usually occurs from trauma. The patient is unable to bend the knee to a functional level.

stiffknee1.png

Trauma will cause adhesions inside the knee, fibrosis, and shortening of the knee ligaments.

There will also be adhesions and shortening of the quadriceps muscles.

stiffknee2.png

Treatment

Treatment will usually begin with therapy. The first surgical option will include an arthroscopy and the release of any adhesions. The second surgical option that may be considered as a quadricepsplasty (Thompson or Judet) or a combination of treatments.

An example of a combination treatment plan would be a modified Judet quadricepsplasty with the release of the quadriceps muscle from the femur and a release of the adhesions that are located inside the knee.

After surgery the surgeon can usually achieve 90° plus flexion.

Osteonecrosis of the Hip

Osteonecrosis or avascular necrosis of the hip is death of a segment of bone in the femoral head due to disruption of the blood supply. The etiology of this condition is not fully understood. There are several risk factors associated with osteonecrosis of the hip.

osteohip1.png

The condition is bilateral in about 80% of the patients. Check the other hip even if it is asymptomatic.

Early diagnosis is important. In early stages of osteonecrosis, a femoral head preserving procedure may be done.  In late stages of osteonecrosis, the femoral head collapses and cannot be saved. The femoral head may need to be replaced.

Obtain AP frog leg lateral views of the hip. The frog leg lateral view will show the crescent sign. MRI is the study of choice especially when the patient has persistent hip pain, radiographs are negative and the diagnosis of osteonecrosis is suspected.

osteohip4.png

The Ficat classification is a commonly used system to stage osteonecrosis of the hip.

  • Stage I: normal appearing X-ray. MRI will detect the lesion (changes in the marrow).
  • Stage II: sclerosis and cyst formation
  • Stage III: subchondral fracture. Crescent sign and flattening of the femoral head.

Stage IV: advanced lesions with arthritis, osteophyte formation and loss of the joint space.

osteohip5.png

Treatment

For early stages of osteonecrosis of the hip, initial trial of non surgical treatment is usually done. Surgery may be needed if non surgical methods are not successful.

Non-operative treatment includes:

  • Bisphosphonates: may also be used before the femoral head collapses. Still experimental.

Traditional surgical treatment: when the lesion is small, a head preserving procedure can be done.

  • Core decompression for stages I and II: can make a single large hole or multiple holes in the femoral head. It decompresses the head and stimulates a healing response. The lesion is anteriorly and superiorly.
  • Core decompression with bone graft: debride the necrotic area and place the bone graft. Some lace this much bone graft.
  • Traditional fibular graft: is done in younger patients.

osteohip7.png

Complications:

  • Donor site pain and leg dysfunction
  • Tibial stress fracture form side the graft is taken.
  • Total hip arthroplasty (cementless cup and stem) or total hip resurfacing. Resurfacing is not commonly used.

osteohip8.png

  • Total hip replacement (predictable): is considered to be the traditional procedure for advanced stages of osteonecrosis of the hip.
  • Total hip resurfacing (controversial): need adequate bone stock to support the femoral component. The result is not as good when compared with a patient with osteoarthritis (older group).