Hip pain, especially pain in the groin area, which is commonly referred to as crotch pain, thigh root pain and hip pain, has always been clinically inaccessible for accurate diagnosis and treatment, and even many experienced senior professors of orthopedics are not familiar with the concept and mostly treat it with strains and lumbar spine problems, with poor results. With the in-depth understanding of the hip joint and the development of hip arthroscopy, femoroacetabular impingement has gradually been recognized by medical doctors.
Femoroacetabular impingement, also known as hip impingement, is a mechanical or structural problem of the hip joint. It can be seen in patients of all ages, including adolescents and young adults.
In a healthy hip, the rounded head of the thigh “slides” into the acetabulum, as if the head of the femur were moving smoothly within the acetabulum. The edge of the acetabulum is surrounded by a special circle of cartilage called the acetabular labrum, which increases the depth of the acetabulum and ensures that the femoral head stays in the acetabulum so that it does not dislocate and run out of the acetabulum when the hip joint moves.
Hip impingement occurs when there is a problem with the smooth, painless, free movement of the acetabular ball: socket.
What are the causes of hip impingement?
The cause may be a deformity of the femoral head, an abnormal femoral neck, or an acetabulum covering too much of the femoral head. Over time, repeated impingement of the femoral head against the acetabular rim causes damage to the cartilage and glenoid labrum.
Many patients with impingement have structural abnormalities of the ball-molar joint at birth, or they develop structural abnormalities gradually during growth and development. Repetitive hip motion beyond the normal range of motion of the joint can easily lead to impingement and is commonly seen in athletes. Trauma can also lead to impingement.
There are two types of impingement.
Cam impingement.
Usually present in men who exercise frequently, it usually consists of the non-spherical portion of the femoral head or a wide spreading protruding deformity of the femoral neck squeezing, colliding and shearing the acetabular cartilage and acetabular labrum during flexion and internal rotation, the shearing forces cause damage to the acetabular labrum from the surface to the interior and tearing from the acetabulum, damage to the acetabular cartilage usually occurs in the anterior upper part of the acetabulum
Clamp impingement.
Usually present in middle-aged women who prefer to be active, it usually consists of abnormal contact between the femoral neck junction and the acetabular rim, with repeated impingement contact leading to degeneration of the acetabular labrum, further causing internal cystic degeneration of the acetabulum as well as peri-acetabular labral ossification and acetabular deepening. This chronic injury is often located in a narrow, elongated area around the acetabular cartilage. The degeneration around the acetabular labrum usually manifests itself in the form of ossification
The two conditions may occur together and are referred to as mixed impingement; in fact, the mixed type is the most common in clinical practice, accounting for 60% to 70% of cases.
Note: Hip impingement is not necessarily associated with the development of osteoarthritis; in fact, it is believed that many patients with hip impingement will develop osteoarthritis in the future if left untreated.
Manifestations of impingement.
Early on, symptoms of hip impingement may not yet be present or may be very mild and atypical. Typical symptoms include
Stiffness in the thigh, hip or groin
Inability to flex the hip past 90°
Pain in the groin area, especially after hip flexion (e.g., running, jumping, or even sitting for long periods of time)
Hip, groin or lower back pain at rest and during activity
Diagnosis of impingement
The diagnosis of hip impingement is very crucial, on the one hand, it determines whether the surgery is good or not, on the other hand, if the diagnosis is missed, hip impingement can lead to further cartilage damage and arthritis.
When a patient comes to the clinic, I first ask the patient about the medical history and subjective sensation, and then conduct a detailed physical examination. Generally, the initial diagnosis of impingement can be made through history taking and physical examination, and then imaging is performed to further confirm the diagnosis.
X-rays: To clarify the overall condition of the hip joint, and to understand the typical impingement at a glance.
MRI: can detect cartilage and glenoid labral damage
CT: thin layer plain scan can detect hidden bone flab, free body, etc., while 3D reconstruction can be performed for a comprehensive view of the hip joint
Treatment of impingement
Patients are seen and I will explain the following treatment modalities, some of which can be cured with conservative treatment, including
Reduction of certain specific types of motion
Physical therapy
Analgesic treatment
Joint injections
In more cases, surgical treatment is required, including both minimally invasive arthroscopic surgery and incisional surgical treatment. Arthroscopic surgery can solve most of the problems due to its small trauma and quick recovery. Through only two small incisions of less than 1 cm, it can complete the intra-articular exploration, clarify the etiology, and perform the cleaning of the femoral redundancy, repair of the acetabular glenoid lip injury, and synovial membrane cleaning, which has become the main method of treating femoral acetabular impingement with good results. Patients should abandon the treatment viewpoint of “tolerate what you can” and actively seek help from doctors. Most patients can get significant relief of symptoms through minimally invasive methods and resume life and work soon after surgery.