Flexor Tenosynovitis of the Hand—Kanavel’s Signs

Flexor tenosynovitis is an infection of the synovial sheath around the tendons of the flexorfingers and hand. The affected finger is red, swollen, and painful due to infection occurring with deep puncture wounds, such as a splinter. Pain is located in the finger at the flexor tendon sheath. Signs of infection of the tendon sheath are called Kanavel’s Signs. There are four Kavanel’s Signs to support the presence of flexor tenosynovitis.

Flexor Tenosynovitis (Kanavel’s Signs)

  1. Uniform swelling of entire finger
  2. The finger is flexed
  3. Intense pain when attempting to straighten the finger
    1. Occurs early
  4. Tenderness along the tendon sheath is the most specific sign.

Treatment consists of antibiotics and surgery may be performed by incision and drainage of the infection.

Hip Dislocation- Sciatic Nerve Injury

Dislocation of the hip is a serious condition that may have significant complications. Pure hip dislocation with or without fracture of the acetabulum or femoral head can cause complications. The worse complication associated with dislocation of the hip is avascular necrosis, due to damage to the blood supply. AVN is death of a segment of the bone in the femoral head. Avascular necrosis may occur if the avndislocation is not reduced in a reasonable period of time. Emergency reduction of dislocations is needed in less than 8 hours of injury. Although x-ray is helpful, a CT scan clearly outlines the bony injury. Other complications associated with dislocation of the hip is injury to the sciatic nerve and arthritis of the hip joint. Injury to the sciatic nerve occurs in about 10-20% of the cases involving posterior dislocation. The sciatic nerve starts in the lower back and runs through the buttock and lower limb. In the lower thigh, just above the back of the knee, the sciatic nerve divides into two nerves, the tibial and peroneal nerves, which innervate different parts of the lower leg. The common peroneal nerve then travels anterior, around the fibular neck, dividing into superficial and deep peroneal nerves. The deep peroneal nerve dives innervation to the tibialis anterior muscle of the lower leg which is responsible for dorsiflexion of the ankle.

tibial common nerve

When injury occurs to the sciatic nerve due to posterior hip dislocation, the common peroneal nerve is usually affected, causing weakness in dorsiflexion of the ankle and loss of toe extension can also occur. Injury to the sciatic nerve usually involves the common peroneal nerve. Injury can occur in carrying degrees of severity and can be missed. Movement of the toes may appear as dorsiflexion; however, this really is the result of plantarflexion. Documenting the injury is important to avoid medical legal problems. Injury to the sciatic nerve typically occurs from the dislocation and not from the reduction. The longer the wait for reduction of the dislocation, the more the patient is predisposed to sciatic nerve injury. The length of time a hip remains dislocated influences the incidence and severity of major sciatic nerve injury. The patient may require an anti-foot drop splint.

foot drop

Peroneal nerve injury/foot drop is treated with physical therapy and waiting. EMG and other nerve studies may be used to assess the condition of the muscles. This condition may take a long time for recovery, usually a partial recovery of the nerve is achieved in a majority of cases. If no recovery is achieved, a surgeon should explore the nerve for repair, graft, or tendon transfer. Sciatic nerve palsy could occur from surgery due to retractors or from traction, usually in posterior hip surgery. Preoperative partial injury of the nerve could deteriorate after surgery. Preoperative documentation of the nerve injury is important.

 

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.

 

Femur Fracture, Subtrochanteric Fracture

Subtrochanteric fractures account for about 10% of all fractures in the proximal femur. This fracture occurs between the lesser trochanter and a point 5 cm distal to the lesser trochanter. The subtrochanteric region is the worst area on the femur for the fracture to occur. There is high compression and tensile forces in the area, as well as less vascularity, less healing potential, and ability. iliopsoasThis area is made of hard cortical bone that does not heal well. There are a lot of deforming forces on the proximal fragment. The subtrochanteric fracture is flexed by the iliopsoas muscle, abducted by the gluteus medius and minimus muscles, and externally rotated by the short rotator muscles. Additionally, there is a high risk of implant failure. A bone to bone transfer may be necessary in this area, especially if the fracture is going to be opened.

There are two types of fractures, atypical and typical. Atypical fractures are associated with bisphosphonate use. Patients will experience thigh pain and usually there is no history of trauma. The fracture may be seen on an MRI. Using bisphosphonate for a long period of time may cause this atypical subtrochanteric fracture of the femur. The fracture may appear as a localized thickening on the lateral side of the femur. When you bend a bone, there will be two parts, a compression component and tension component. In an x-ray, the compression component will signal an oblique “spike” on the medial side and there will be no comminution. The tension component will be on the lateral side. Typical fractures usually occur due to high energy trauma such as car accidents or from a fall.

fracture in areaIn the majority of subtrochanteric fractures, either typical or atypical, we will use a rod. Because the rod is inside the bone, and not outside the bone like a plate, this area is suitable for IM nailing. The rod location will result in a shorter lever arm and lower bending moment on the device. The rod will be closer to the center of motion of the body than a plate, which is on the lateral surface of the bone, further away from the center of motion of the body. Therefore, rods are subjected to smaller bending loads and less likely to result in fatigue failure. The IM rod is minimally invasive and they do not destroy the extramedullary blood supply. IM rods are load sharing so you can initiate weightbearing. IM rods are stronger than plates. You must reduce the fracture before reaming and insertion of the rod.

im rod

The disadvantage is that an IM rod may create varus and procurvatum deformity (flexion). There is more varus with trochanteric entry. There may also have perforation at the anterior cortex distally due to mismatch between the radius of curvature of the nail and femur. The IM rod is not preferred in the treatment of subtrochanteric fracture that extends into the piriformis fossa or the greater trochanter. A fixed angle plate may need to be used to avoid excessive dissection medially. A bone graft may be used to avoid nonunion. A bone to bone transfer will be necessary medially. The patient should try to avoid early weightbearing. The plate induces fracture healing through primary bone healing. The rod induces endochondral ossification, secondary bone healing (more abundant bone healing). If there is enough segment of the proximal fragment that you can place a diagonal screw, this means that you have a large piece of bone and a standard IM nail may be used. If there is not enough bone segment to place a diagonal screw, then you need to place the screws on the head, called cephalomedullary nailing. If the fracture extends to the piriformis fossa or the greater trochanter, then you probably need to use a fixed angle plate.