Hip pain is a descriptive term for pain that is located around the hip joint region.
Hip pain is a descriptive term for pain that is located around the hip joint region. The hip joints attach the lower limbs to the trunk and hence, our body weight can be transferred downwards through the hip joints to the foot on the ground. The hip joint also provides motion in all 3 anatomical planes (flexion and extension in the sagittal plane, abduction and abduction in the coronal plane and internal and external rotation in the horizontal plane). Its range of motion is the second largest in the body, only to the shoulder joint.
The hip joint is formed by the articulation of the rounded head of the femur and the cup-like acetabulum of the pelvis. The joint surfaces on either side are covered with a strong but lubricated layer of hyaline cartilage. The articulation is covered by the joint capsule which, in turn, is reinforced by surrounding ligaments to provide mobility, stability and to prevent excessive movements of the joint.
There are 4 extra-capsular ligaments. The three strong ligaments are iliofemoral, ischiofemoral, and pubofemoral ligaments, which attach to the corresponding part of the pelvis, the ilium, the ischium and the pubic bone on one end and to the femoral bone on the other end. The Y-shaped and twisted iliofemoral ligament is the strongest ligament in the human body. In standing position, it prevents our body from falling backward without the need of muscular activity. The ischiofemoral ligament prevents excessive medial rotation while the pubofemoral ligament restricts excessive abduction in the hip joint. The fourth ligament is zona orbicularis, which is a collar ring ligament around the narrowest part of the femoral neck at the base of the head of femur. It is formed by the circular fibers of the articular capsule of the hip joint and acts like a buttonhole on the femoral head to maintain its contact with the acetabulum fossa.
The pathologies of hip joint can be classified according to the cause:
It is interesting that hip joint problems are not uncommon in the paediatric patient group. Transient synovitis which may be caused by viral infection is a common cause of hip pain and limping gait in children. Perthes disease is a temporary loss of blood supply to the femoral head among children which can lead to avascular necrosis of the head of femur if left untreated. It is much more common in boys than girls (4:1). Slipped capital femoral epiphysis occurs less commonly, but can affect children and adolescents with boys to girls about 2:1. It is caused by the displacement of the femoral head along the unstable growth plate posteriorly and inferiorly in relation to the femoral neck and within the confines of the acetabulum. In general, about 20% of patients have bilateral involvement at the time of presentation. There is an increased risk in children who are obese moves through the growth plate relative to the rest of femur.
Symptoms and signs:
The symptoms and signs are variable depending on the underlying pathology. Hip pain can be caused by pathologies inside the hip, pain referred from other structures to the hip and pain generated biomechanically from problems of the back above and knee and foot below.
Hip-related pain is not always felt directly over the hip. As the hip joint is three-dimensional, pain may be also felt along the outside part of the hip, in the buttock area or even radiate down to the knee region.
Pain from other sources, like low back, sacroiliac joint, knee joints or even pelvic organs, can be referred to the hip. Iliopsoas strain or iliopsoas bursitis are two common causes of groin pain that can be mistaken as hip pain. Typically the pain is felt in the front of the hip and groin and is aggravated by flexion of the hip – as with going up stairs. It is crucial to look for other primary pathology if hip joint examination is unremarkable. Among the other common causes are adductor strain or adductor tendinitis (groin pull) which are most common in sprinters. Occasionally, pain around the hip can be referred pain from trigger points of the Quadratus lumborum muscle.
Pain in the hip can be generated from overuse use or misuse of the hip because of biomechanical derangements. Abnormal gait can cause pain inside the hip. Limping can be caused by problems in the foot, ankle and knee. It is the way that our body compensates for pain by trying to reduce the force loaded onto the joint with pathology while walking. Limping is never normal. When limping occurs, abnormal stresses are placed on the joints above and below. In the case of knee problems, for example, the body loading will be shifted upward to the hip and downward to ankle causing hip and ankle pain.
Reduced range of movement can be found if the joint is degenerated or acutely inflamed. The most commonly affected movement is internal rotation of the hip joint. Rarely, swelling and erythema can be found around an inflamed hip joint as the joint is deeply located.
Hip pain is a non-specific complaint that requires a doctor to work out the exact underlying causes. Therefore, careful history and physical examination are important. Investigations are sometimes needed to confirm the diagnosis. X-ray hip is a simple and safe procedure to document fracture, dislocation and late avascular necrosis of the hip. Musculoskeletal ultrasound can helps to visual tendinosis, muscle tear and inflamed bursitis. CT scan can help to pick up some subtle fracture. MRI is good to see surrounding soft tissue, but expensive. A musculoskeletal physician will have the expertise to diagnosis a hip pain and confirm the diagnosis, if necessary, with the most cost-effective investigation.
Treatment depends on the cause of hip pain. For hip OA, a musculoskeletal physician will use non surgical treatments like weight reduction, analgesics and physical therapy. For those severe cases that do not respond well, prolotherapy is employed to strengthen the degenerated hip ligaments and stabilize the hip joint to reduce pain. Prolotherapy is especially good for those patients who do not opt for total hip replacement surgery. Surgery is the best treatment method for fracture neck of femur. Immunotherapy is an advanced treatment for hip pain from autoimmune diseases.
小童的髖關節問題並不少見。病毒感染引起的暫時性滑膜炎 (transient synovitis) 是小童髖關節痛和跛行的常見原因。Perthes 病是由於股骨頭的血液供應暫時受阻所致，若不給予治療會發展為缺血性壞死，男孩發病遠多於女孩（4：1）。股骨頭骨骺滑脫症較少見，但偶爾也會發生於兒童和青少年，是由於股骨頭在髖臼內沿未癒合的骺板向後和向下移位造成，總體來講，男女比例為 2：1，就診時雙側受累者佔 20%，肥胖兒童發病風險增高。
Date: 13 – 14 July 2019
Venue: Hong Kong Academy of Medicine Jockey Club Building
Theme: Point of Care of Musculoskeletal Ultrasound in Primary Care
Diagnostic Musculoskeletal Ultrasound Workshop
Date: 2 – 3 November 2019
Venue: Hong Kong Academy of Medicine Jockey Club Building