Is your hip causing knee pain, or vice versa?
Adults with knee pain account for approximately four million primary care visits yearly, according to the American Academy of Family Physicians. This number has increased almost 65 percent over the past 20 years.
While people often see their primary care physicians initially for an exam and X-rays, they may be referred to an orthopedic surgeon for further evaluation, especially if their pain is ongoing.
“The most common cause of knee pain I see in my office is knee arthritis,” said Jonathan Sunkin, MD, an orthopedic surgeon at Falmouth Orthopedic Center. “But sometimes, people will come to the office complaining of terrible knee pain and are surprised to find it’s not the knee that is causing their pain, but their hip or back.”
How to Tell the Difference
Differentiating the source of pain begins with an exam and testing.
“As a part of the knee exam, I will look at the X-rays and if they are normal, I will order an MRI (magnetic resonance imaging),” said Dr. Sunkin. “If the patient has received cortisone injections in the knee, I will ask if the injections relieved the pain. If the MRI is normal and the injections have not relieved the pain, then I know to look at the hip and/or back.”
Dr. Sunkin will also routinely check the internal and external rotation of the hip as part of the knee exam “because sometimes when I internally rotate the hip, it will elicit the same pain, and if I discover stiffness with hip motion, then that is a good hint to get a hip X-ray, even if the patient is complaining of knee pain.”
There are several things to take into consideration when diagnosing knee and hip pain, according to Dr. Sunkin. For instance, arthritis in the back, hip and knee can cause pain.
“If you have arthritis in your back or hip, that can cause pain in your knee,” he said. “The hip can become stiff and cause you to overuse adjacent joints to compensate. Your knee will work harder to compensate for your hip and could also throw your back out of alignment. Your spine is compensating for your stiff hip. This can be confusing because the hip pain may really be what is causing back pain.”
Tightening of the iliotibial band in the hip, which is a stout piece of tissue that runs from the top of the pelvis in the iliac bone to the outer portion of the tibia, can be painful. It runs from the top of the pelvic bone down to your knee. When it becomes tight, it can cause lateral (outer side) hip pain, also called bursitis, and lateral knee pain at the bottom of the band. Physical therapy can be very effective in loosening the band, Dr. Sunkin said.
A labrum, which is a ring of cartilage that goes around the acetabulum of the hip, can get worn over time and tear, causing pain in the hip. The meniscus in the knee can have the same fate and cause knee pain.
A pinched nerve in your back (lumbar radiculopathy) causes sciatica (pain going down your leg) but it can lead to lateral hip pain, too.
A Process of Elimination
“Cortisone injections can be very helpful because they are diagnostic and therapeutic,” said Dr. Sunkin. “The injection stays right where you inject it into the joint and if it offers good relief even for a brief period of time, it makes me feel more confident that it is truly what is causing the pain. The shot can take up to two weeks to kick in and if it hasn’t relieved their pain even briefly after six weeks, then I know that is not the source of the pain.”
Cortisone shots can be administered into the bursa of the hip to relieve the pain from bursitis, said Dr. Sunkin. If the injection works, then the hip is the source of pain, and if it doesn’t, then I will get an MRI of the back to make sure there isn’t something going on in the back that is causing the hip pain.
“When it comes to assessing a patient with knee pain, it’s important to remember to check the hip and the knee together, and the hip and the back,” he said.
