Medical Mystery: Ongoing knee pain, with no relief from steroid injections
Despite not experiencing an injury to his knee, the symptoms were beginning to limit the man's ability to stay active, resulting in weight gain.
Gary is an active 74-year-old who, despite his busy travel schedule for work, would walk or cycle several miles a day. Six months ago, he began to experience tightness in the front of his thigh and discomfort in his left knee during his daily exercise.
Although he had not experienced an injury to his knee, the symptoms were beginning to limit his ability to stay active, resulting in weight gain. Concerned about the possibility of arthritis, he made an appointment with his physician for examination.
An X-ray of his left knee showed some mild, but age-appropriate, joint space narrowing in his cartilage.
Because an X-ray is taking a three-dimensional object and rendering it in two-dimensions, it is possible for patients to have a cartilage defect that does not appear in the X-rays. If the cartilage defect is small enough, the patient’s X-ray can appear relatively normal.
Because Gary’s symptoms were consistent with arthritis and his X-rays showed mild joint space narrowing, his doctor recommended a steroid injection in the knee.
Steroid injections typically contain a local anesthetic and corticosteroid, which means the injection is both diagnostic and therapeutic. If the source of the pain is within the joint, the local anesthetic will work to temporarily “numb” the area of arthritis, helping to confirm the diagnosis. The corticosteroid will act as a strong anti-inflammatory agent to hopefully diminish the patient’s symptoms for an extended period of time.
Gary, unfortunately, did not get even temporary relief from the injection.
What was the real cause of his knee pain?
Solution
After Gary attempted, without success, another type of injection commonly used to treat arthritis of the knee, he came to see me with the hope of providing him relief from his symptoms.
After I heard about his lack of a response to the steroid injection, my physical exam was more focused on investigating for tendinitis or bursitis (inflammation of the fluid-filled pads that act as cushions at the joints). The exam did not provide evidence of either condition.
Because arthritis in the hip or spine can cause referred knee pain, my examination shifted to investigating for a more remote source of his symptoms. Bending and rotating Gary’s hip consistently reproduced his left knee symptoms.
I suggested an X-ray of Gary’s left hip, which confirmed my suspicion: severe bone-on-bone arthritis of the hip.
Because Gary had not exhausted the nonsurgical treatment options for hip arthritis, he elected to attempt a steroid injection in his hip.
It is common for patients with hip arthritis to have referred knee pain, but patients typically have accompanying groin pain. Because Gary did not have groin pain, the steroid injection would also provide more confirmation of the diagnosis of hip arthritis causing his knee symptoms.
Gary responded briefly to the steroid injection, which eased his left knee pain for a couple of days. Unfortunately, he did not have a lasting response, which we typically hope will continue for at least three to four months.
We discussed a hip replacement to help provide him with long-lasting relief from his symptoms and improved function.
Yale A. Fillingham is a board certified joint replacement surgeon at Rothman Orthopaedic Institute.