The first noticeable symptom of femoroacetabular impingement is often deep groin pain with activities that stress hip motion. Prolonged walking is especially difficult. Although the condition is often present on both sides, the symptoms are usually only felt on one side. In some cases, the groin pain doesn't start until the person has been sitting and starts to stand up. There is often a slight limp because of pain and limited motion. Groin pain associated with femoroacetabular impingement can be accompanied by clicking, locking, or catching when chronic impingement has resulted in a labral tear. When femoroacetabular impingement and a labral tear are both present, symptoms get worse with long periods of standing, sitting, or walking. Pivoting on the involved leg also reproduces the pain. Some patients have a positive Trendelenburg sign (hip drops down on the right side when standing on the left leg and vice versa).
As is often the case, one problem can lead to others. With femoroacetabular impingement, hip bursitis can develop. The gluteal (buttock) muscles may be extra tender or sore from trying to compensate and correct the problem. The pain can be constant and severe enough to limit all recreational activities and sports participation.
How do health care professionals diagnose the problem?
Diagnosis begins with a complete history of your injury. Your Physical Therapist at Actify Physiotherapy will ask questions about where precisely the pain is, when the pain began, if there was a specific injury that occurred or whether the pain gradually developed over time, and what movements aggravate or ease the pain. They will inquire about any previous injuries to the hip, low back, knee or even ankle, which may have contributed to the hip or groin pain you are feeling now. Your therapist will also ask about any swelling, clicking, catching, or weakness in the hip or groin area.
Next they will do a physical examination. Your Physical Therapist will first look at your posture and alignment in standing. They may also check to see if you have a leg length discrepancy that is contributing to your injury or dropped arches that can also change your entire lower limb alignment. Next they will palpate all around your low back, pelvis, groin, and also the side and back part of your hip including into your buttocks muscles in order to determine your most tender point. After determining your most sore point they will check the range of movement in your hip by passively moving your hip into many different ranges of motion. Motion in your pelvis and low back may also need to be checked. With FAI often the range of movement of the involved hip is not the same as the normal hip. Depending on the cause of the FAI the range of motion may appear to be restricted or may even appear to be overly mobile, particularly in one direction. In addition the muscles both at the front and back of the hip joint may be tighter than they should be.
The strength of your muscles around your groin and hip as well as your knee and core will be assessed next. Your therapist will ask you to resist certain movements while checking for pain as well as strength deficits. Often with FAI the gluteal muscles are weak on the affected side, which creates a muscular imbalance affecting the biomechanics at the hip. Your therapist may also want to watch you do things such as walk, jog, mini squat on one leg, or hop in order to assess your overall biomechanics.
Other specific tests may be done to provoke your symptoms and test for excess or restricted movement at the hip joint. In one common test done for FAI the patient lies on the table on his or her back. Your Physical Therapist then bends your leg up, internally rotates the hip, and presses the knee toward the other leg. This position puts the hip in such a position that impingement occurs and often reproduces the painful symptoms. If you have an inflamed bursa at the front of the hip, this position will also be irritating for it.
Several imaging tests can be done to identify what's going on including X-rays, magnetic resonance images (MRI), and computed tomography (CT) scans. X-rays show the presence of any extra bone build up as well as the position and alignment of the bones and joint. X-rays also show the shape of the femoral head. Any asymmetries (i.e., where the head is not an even round shape compared to the other side) are also visible on X-rays as well as indications for a retroverted hip, which is, in simple terms, a hip bone that is angled backwards. MRIs can show any damage to the labrum but not necessarily any changes to the surface of the hip joint. The presence of edema (swelling) under the bone may show up and requires further evaluation to decide if it is from femoroacetabular impingement or some other cause (e.g., cyst, tumor, stress fracture). Using MRI with a dye injected into the joint (called magnetic resonance arthrography or MRA) provides greater detail of the joint surface and may be needed. CT scans help show the exact shape of the bone and reveal any abnormalities in the bone structure. CT scans might be the most helpful when arthroscopic surgery is planned as they give the surgeon a better idea of what needs to be done to reshape the bone. If the procedure is going to be done with an open incision, then the CT scan isn't necessary, as the surgeon will see everything once the area is opened up.
On the next posting we will be discussing the possible treatments available for FAI. If you have any questions feel free to contact us.