The profunda femoris artery is the main blood supply of the
thigh. The profunda femoris artery arises from the posterolateral aspect of the
femoral artery about 4 cm below the inguinal ligament. The profunda femoris
artery crosses the pectineus muscle and the adductor brevis muscles, and runs
under the adductor longus muscle. Then it runs between the adductor magnus and
the adductor longus muscles. When it reaches the adductor magnus, it gives
three perforating branches and it ends by perforating the adductor magnus as
the fourth perforating branch. The perforating arteries are called “perforating”
because they perforate the insertion of the adductor margnus in order to reach
the back of the thigh. The first three perforating arteries are branches of the
profunda femoris itself, while the fourth perforating artery is a continuation
of the profunda femoris artery itself. During posterior exposure of the hip,
partial section of more than 2cm of the gluteus maximus tendon attachment on
the femur can be associated with a risk of injury to the first perforating
branch. The profunda femoris artery gives the medial circumflex femoral artery
and the lateral circumflex femoral artery. The MCFA will give the ascending,
the acetabular, and transverse branches. The LCFA will give the ascending, the
descending, and transverse branches.
Stem cells may help tissues that are injured or damaged to
renew and regenerate themselves. Depending on the treatment and medium, stem
cells have the ability to become different types of cells such as bone,
cartilage, and blood vessels. There are several conditions in which stem cells
are used as treatment, including: avascular necrosis, arthritis, and nonunion.
When Avascular Necrosis of the femoral head occurs due to
the diminished blood supply, there is a death of a segment of bone, which is
considered necrotic. The surgeon can inject stem cells into this area to revive
this area by drilling into the bone. When using stem cells to treat AVN, the
surgeon will need to create a channel for new blood vessels to form into the
area that lacks blood supply. After the channel is created, the stem cells are
injected into the necrotic femoral head.
Stem cell treatments for joint pain and arthritis is not
proven to be effective. However, there is some use in knee arthritis for
cartilage regeneration.
The best use of stem cells in Orthopaedics is its treatment
for nonunion fractures. A nonunion fracture is classified as a fracture that
does not heal after a reasonable period of time or a fixation failure. Nonunion
may also be due to motion of the bony ends and incomplete healing of the
fracture; fractures of this nature will need a lot of assistance. Two elements
are needed for treatment of nonunions: vascularity—which improve the local
conditions to facilitate healing; and stability—in the form of fixation such as
a rod or plate.
The most common causes of nonunion are smoking (5 times more
common), diabetes, obesity, osteoporosis, unstable fixation, infection (most
common), open fractures, and the severe displacement of the fracture.
Options available for treatment:
Bone Morphogenetic Protein—very expensive
Bone Graft—donor site morbidity
Stem Cells
Stem cells must be extracted from the bone marrow and are
aspirated and harvested from the anterior iliac crest. This procedure is
performed with an outlet view under fluoroscopy. Once extracted, the bone
marrow is prepared to be centrifuged. After centrifuging the bone marrow, a
good sample is extracted for injection.
The surgeon will mark and localize the
area for injection and the trocar is placed. The sample will then be injected
into the fracture area—occasionally, two areas of nonunion are treated. Adult
mesenchymal stem cells are special cells that can copy themselves, divide, and
multiply. They can differentiate into bone cells that heal the nonunion and lay
down new bone. This process can be monitored by alkaline phosphatase activity
or by the genes of the stem cells. The whole cellular mechanism can help increase
the vascularity of the nonunion.
It is important to note that adult mesenchymal stem cells
are not embryonic stem cells. There is a large amount of information in regards
to stem cells that is lacking or misleading. Cells should probably be combined
with some type of matrix. Additionally, surgeons need a better delivery system
and localization during the injection of the stem cells due to the fact that
the dye kills the cells. It is beneficial to allow the cells to expand and grow
in the culture prior to injection. Moreover, the effect of certain medications
such as aspirin, Plavix, and Coumadin, should be studied further.
Pelvic fractures may cause significant bleeding. The
superior gluteal artery is responsible for the majority of bleeding in pelvic
fractures with an arterial injury. Most of the bleeding in pelvic fractures is
from the veins and the fracture itself. Hemorrhage is the most life-threatening
complication associated with pelvic injuries and will typically occur at the
Superior Gluteal Artery. Hemorrhage of the Superior Gluteal Artery can be
fatal. Approximately 10% of patients will have severe bleeding. Severe bleeding
usually occurs in fracture patterns that are highly unstable to both rotational
and vertical forces.
APC III (open book like type) is the complete disruption of
anterior SI, sacrotuberous, and sacrospinous ligaments; disrupted posterior SI
ligaments.
Vertical Shear Fractures are very bad fractures as they
cause the complete disruption of the anterior and posterior ligaments;
cephaloposterior displacement. Anteroposterior compression or vertical shear
injuries are consistently associated with a higher risk of mortality from bleeding.
The mortality rate is directly related to the amount of shock the patient is in
at the time of presentation.
When treating patients with pelvic fractures and massive
bleeding, it is important to remember that the patient will lose approximately
35% of their blood volume with acute hemorrhage before a sustained decrease in
systolic blood pressure occurs. Immediate application of a pneumatic anti-shock
garment is absolutely contraindicated in patients with a rupture of the
diaphragm. Ringer’s lactate is the preferred initial fluid replacement used to
resuscitate hypovolemic trauma patients in shock. A hypotensive blunt trauma
patient will be given an initial fluid push with 2,000mL of Ringer’s lactate. A
patient with bleeding and in shock will probably require O negative blood. If
the patient is given 4 units of blood but remains hemodynamically unstable,
then angiography and embolization is needed. Immediate application of an
external fixator is another method to control bleeding, especially if the
pelvis is unstable in external rotation. An abdominal and pelvic CT scan will
clearly define the bony injury as well as the extent and source of the
bleeding.
The best treatment for pelvic fractures with bleeding is a
blood transfusion with correction of hypothermia and coagulopathy.
