Of
the joints in the leg that are commonly injured in runners, hip pain
often poses the most difficult diagnosis. There are a couple of reasons
for this: First, there are simply too many possible causes of hip pain,
and a second, less obvious reason, relates to the frequency of these
injuries.
The bony anatomy of the hip is actually quite straightforward. The
head of the femur ends in a ball that articulates with a pocket in the
pelvic bone, the acetabulum. This forms the classic ball-in-socket
joint. Yet, because of the extreme forces that this joint is subjected
to, especially when running, and because of the very complicated
supporting structures that help make it among one of the strongest and
most stable joints in the body, many potential sources of hip pain are
possible. Because the hip plays such an important role in weight bearing
and locomotion, it is of the utmost importance to identify these
injuries as early as possible, and treat them before they result in
joint damage.
We’ll review the more commonly encountered causes of hip pain in
runners: muscular strains and pulls in the groin, hamstring or
piriformis, hip flexor tightness, bursitis, stress fractures and labral
tears. Iliotibial band friction syndrome (ITBFS) may also cause hip
pain, but has been widely covered, and therefore will not be discussed
in this article.
Groin Pulls or Tears
A pulled groin is caused by a strain in the hip adductors, muscles
that pull the legs together. These muscles attach to the thighbones at
the level of the hip and run down the inside of the thigh, stabilizing
the joint. When overstretched or overused, small tears can develop
resulting in hip pain, swelling, and a dull ache in the groin area.
Severe tears occur more suddenly and are associated with very sharp pain
and bruising down the leg.
Unfortunately, many hip injuries can cause groin pain as well, so
distinguishing a true groin pull from other possibilities may not always
be that straightforward. Usually a focused history and physical exam
suffice to confirm the diagnosis.
The treatment of a groin pull is similar for other pulled muscles.
Rest, ice, compression and elevation can all help to alleviate symptoms.
Anti-inflammatory medications or acetaminophen can be used to treat
pain and once the injury has healed sufficiently, a gradual return to
activity can then follow.
Hamstring Injuries
The hamstrings are made up of three distinct muscles that run down
the back of the thigh, which then operate together as powerful knee
flexors. Like all muscular injuries, hamstring injuries occur when
fibers within the muscles tear. The severity of the injury is determined
by the amount of damage and how completely the fibers are torn—the
least severe form being a strain, while the most severe consists of a
complete tear.
Hamstring injuries are almost always associated with pain in the back
of the leg that gets worse with flexing the knee. However, if the
injury is higher up in the muscle body, then the symptoms can be
experienced in the hip itself.
Piriformis Syndrome
The piriformis is a small muscle that runs from the sacrum to the
outside of the hip. For a small muscle it can cause big problems when
inflamed or overused. Because it runs over the sciatic nerve, the
piriformis has a nasty habit of putting pressure on this nerve and
causing exquisite pain in the glute and posterior hip area when it
swells or spasms.
Aside from addressing any mechanical issues that might be
exacerbating the problem the main way to treat piriformis syndrome is by
stretching the muscle out as much as possible. To stretch the
piriformis: lay on your back, bend your knees and cross your right leg
over your left so your right ankle rests on your left knee in a figure
four position. Bring your left leg toward your chest by bending at the
hip. Reach through and grab your left thigh to help pull everything
toward your chest.
Iliopsoas Syndrome
The iliopsoas muscle is a powerful hip flexor that runs across the
top of the hip joint and works to pull the knee up and off the ground
when it contracts. Movement of the tendon is facilitated by the
iliopsoas bursa. If the tendon or the bursa becomes inflamed, flexion
may become very painful and the pain is felt in front of the hip with an
associated snapping or clicking sensation during movement. Iliopsoas
syndrome often arises as a result of increasing volume or intensity too
quickly, and hence this problem may be easily avoided. Once it has set
in though, the only effective treatment is rest with liberal use of
anti-inflammatory medications.
Hip Bursitis
Bursae are fluid-filled sacs that assist in lubricating the movement
of structures around joints. The hip bursa allows for the smooth
movements of various tendons over each other as the hip ranges in
different directions. In some instances this sac can become inflamed
after repetitive micro-trauma common in long-distance running. The
inflammation can be very painful with symptoms predominantly over the
outer aspect of the hip radiating down into the thigh.
Once inflamed, the treatment for hip bursitis is similar to many of
the other injuries described here: rest, the application of ice and the
use of anti-inflammatory medications. Although it is rare, in some cases
the bursitis may become severe or chronic and require surgery.
Stress Fracture
Although much more common in the foot and lower leg, stress
fractures of the hip may also occur. Stress fractures result from a
combination of overuse in the setting of muscle fatigue, and in some
cases, predisposed anatomical issues. Under normal circumstances the
muscles and tendons absorb the vast majority of the forces transmitted
during repeated ground striking in running. However, with progressive
fatigue, more and more of the force is transmitted to the underlying
bone, and with time the bone may fracture.
Unlike a traumatic injury, in which there is a sudden tremendous
force applied that results in an obvious disruption of the bone, stress
fractures are insidious and take time to manifest symptoms. Stress
fractures of the hip will cause a dull ache either felt in the groin or
lower back, and this can delay the diagnosis allowing more time for the
fracture to worsen. Once suspected, confirming the diagnosis can also be
difficult as the bone may appear normal on plain X-rays. Only more
advanced imaging will show the problem definitively.
Once diagnosed, a complete cessation of weight bearing exercise is
mandated. This is critical in order to prevent the stress fracture from
progressing to a much more serious and complete fracture. The duration
of recovery will depend on the severity of the injury and, in rare
cases, surgical intervention may be required.
Hip Pain Due to Labral Tear
The labrum of the hip is a cartilage ring that forms a kind of
lubricating O-ring around the ball of the femur holding it in place in
the acetabulum. In some people, bony abnormalities either of the neck of
the femur or of the lip of the acetabulum can cause the labrum to
become repetitively impinged with normal ranging of the hip joint. Over
time, this impingement causes the labrum to fray and eventually tear.
Until recently, the long-term importance of labral tears wasn’t
completely appreciated. Now, these tears are seen as a potential
contributor to the early development of arthritis of the hip.
Because the labrum is made of cartilage and therefore completely
insensate, the symptoms of a labral tear arise only long after the
damage has been done. Patients with this problem frequently complain of
pain in the groin that gets worse when crossing the affected leg over
the other. Hence, the diagnosis is difficult to confirm and requires an
MRI with contrast injected into the joint. Once confirmed, the only
treatment options for symptomatic patients are the complete cessation of
weight bearing activities or surgery. It is important to note that not
all patients with labral tears require surgical repair. This should be
discussed with an orthopedic surgeon familiar with the diagnosis and the
procedure to address it.
The hip joint is less prone to injury than the lower leg but can
still be afflicted by a number of issues both big and small. Quickly
arriving at the correct diagnosis is an important part of getting
effective treatment and returning to activity. Knowing the common causes
of hip and groin pain is also an important part of that equation. See
your physician whenever you have vague, non-specific pains that are
difficult to ascribe to a specific area. This can often end up being
something more important than you might initially think and catching it
early is key.
