Hip

Hip Trauma: Hip Contusion

Normal Anatomy

The hip joint functions as one of the most important joints in the human body. Designed for both mobility and stability, the hip allows the entire lower extremity to move in three planes of motion, while providing an important shock absorption function to the torso and upper body. The hip is a ball and socket joint, uniting the femur (thigh bone) with the pelvis. As a result of this configuration, the leg moves forwards and backwards, side to side, and rotates to the right and left.


The pelvis features two cup-shaped depressions called the acetabulum, one on either side of the body. The femur, or thigh bone, is the longest bone in the body and connects to the pelvis at the hip joint. The head of the femur, shaped like a ball, fits tightly into the acetabulum, forming the ball and socket joint of the hip.


Embedded within the acetabulum of the pelvis lies an important structure lining the joint known as articular cartilage; this cartilage has two very important functions. First, the smooth, low friction surface of the cartilage allows the hip joint to move freely in all planes of movement. Second, the articular cartilage cushions the hip during weight bearing activities, providing an important shock absorption function to the entire lower extremity.


The hip joint also features a complex system of ligaments that provide stability for the pelvis and lower extremity. The ligaments of the hip joint connect the femur to the pelvis and are essential to keeping the hip from moving outside of its normal planes of movement.
The muscles of the hip joint have dual responsibilities. They provide the dynamic functions necessary to raise and lower the lower extremity as well as the stabilizing functions required during standing, walking, or other weight-bearing exercises. This complex system of muscles works synergistically to provide the power for the hip to move in all directions, as well as to stabilize the entire lower extremity during weight-bearing activities.

Pathology

Trauma is the term used to describe injury. Trauma is classified by its severity depending on the amount of force used to cause the injury. Trauma is also distinguished according to whether it is caused by a single major force or minor repetitive, smaller forces which are cumulative (additive) over time. This is referred to as Cumulative Trauma Disorder (CTD). An injury is also classified depending on if the skin was breached, called an open injury or the skin layer stays intact, referred to as a closed injury. When an injury is minor, it is called a contusion and in this instance, it implies that the injury was closed and only involves the soft tissues including the skin, subcutaneous tissue, muscles, tendons, ligaments, arteries and nerves, alone or in combination. In a contusion, the soft tissue is bruised or stretched, but not torn and requires only symptomatic treatment. The same force of trauma sustained by different patients will result in different injury severity because changes that occur in our body’s internal structure with aging. Specific changes occurring with aging is the amount and type of collagen in our body through metabolism is converted from Type I collagen which is the typical collagen most often found in the human body is converted into Type II collagen. Type II collagen is less resilient and is the type of collagen found in healing scar. The protein, elastin, which gives tissue its stretch properties, also decreases in content with aging. Finally, the water content in the cells of the body decrease with aging. Below is a graph that depicts an identical force sustained by individuals at different ages divided into 20-year increments and the time it takes for each group to heal and become symptom-free. The white section is when the patient is symptom-free and the yellow section is when the patient is having symptoms including pain, stiffness, weakness, and poor function. Note the curve does not come back to baseline and shifts to the right with aging.

Treatment: Hip Contusion

The most common symptomatic treatment used for all types of soft tissue injuries has three components:

1. R.I.C.E. treatment,
2. Anti-inflammatory medication,
3. Controlled early motion and therapy.

The acronym RICE stands for Rest, Ice, Compression and Elevation. A Strain is a muscle injury, a Sprain is a ligament stretch injury and both conditions are treated in this manner. Rest is usually done for 24-48 hours, and can include the use of slings, splints or other types of immobilizers, unless otherwise advised by a physician. Ice is used for 20-30 minutes at a time, 3-4 times per day. Ice is best applied by using an ice slush, which transmits the effects of the cold sensation best, and can be made by crushing ice, mixing it with water, and then placing it in a Zip-lock® plastic bag. The ice bag should not be placed in direct contact with the skin, but instead should have a layer between the skin and ice bag, like a towel, to prevent the skin from freezing. The ice should be applied for no more than 20-30 minutes to avoid skin freezing, which can occur if a patient falls asleep with an ice pack on his/her limb. Ice functions by causing arteries to narrow in size, which decreases swelling and the pain from swelling.

Compression is the wrapping of a body part to further assist in minimizing swelling and is used in conjunction with Elevation. The best way to make a compressive wrapping is for the compression to have multiple layers that provide a cushioning effect. Compression should be wrapped without causing constriction of the blood supply, which can be signaled by increasing pain to the body part wrapped. Other signs a compressive dressing is too tight is an overly-cold sensation of the wrapped limb, blue discoloration of the body part, or any change in color from the patient’s natural skin color. Elevation of an injured body part is best done by elevating the limb to the level of the heart. If elevation is lower than this, the effect of gravity on the veins will increase vein pressure and cause the blood in these veins to have difficulty traveling back to the heart and result in continued limb swelling.

The use of Anti-inflammatory medication helps treat the pain, swelling, and inflammation that occur after an injury to a limb. Examples of anti-inflammatory medications include aspirin products, ibuprofen (Motrin®/Advil®), naproxen(Aleve®/Naprosyn®), meloxicam(Mobic®), indomethacin(Indocin®), Arthrotec®, and Celebrex®, to name a few. All of these medications have side effects and should be taken with this knowledge in mind. Prescriptions should be discussed with your pharmacist and physician.


Controlled early motion and therapy for the involved limb decreases the effects of prolonged immobilization, which include stiffness, muscle atrophy, weakness and a longer return to the pre-injury state. The type of therapy recommended will depend on the tissue type injured and the severity of the injury. Consult your surgeon for the best advice.