Hip pain is a common complaint of many children and adolescents. There are a wide variety of causes ranging from simple trauma to juvenile arthritis to cancer. Typically, the history, onset of the pain and age of the patient help with the diagnosis along with a physical examination and imaging studies.
Infectious
Infectious causes of hip joint pain include septic arthritis and bacterial osteomyelitis. These diseases typically cause unilateral joint involvement and patients tend to appear sick.
Septic arthritis refers to the presence of an infection of the synovial tissue of the joint with pus in the joint cavity. The infectious process is capable of rapidly destroying the joint. Patients usually have a fever along with a painful and swollen joint. The treatment typically involves antibiotics and possible surgical wash-out (irrigation) of the joint. Dr. Ahmed Mounir Moustafa El-Sayed of the University of Menoufiya in Egypt reported in the "Journal of Children's Orthopaedics" that arthroscopic drainage is effective as a minimally invasive procedure to wash out the septic hip joint. The gold-standard of treatment continues to be a large incision and washing out the joint.
Osteomyelitis is a bone infection that can be acute or chronic in onset. The condition can be caused by a variety of bacteria or fungus. It tends to be more common in diabetics, hemodialysis-dependent individuals, immunosuppressed patients, sickle cell disease and intravenous drug users. The symptoms include pain, tenderness, fever, nausea and occasionally pus drainage through the skin (through a sinus tract). Treatment is with antibiotics and possibly a surgical irrigation and debridement (washing out the joint and cleaning up infected portions).
Rheumatologic/Arthritis
Rheumatologic causes of hip pain usually present as more than one joint, but can involve a single hip joint. There are many types of rheumatologic causes of hip pain. Juvenile idiopathic arthritis (JIA) is the common rheumatologic condition that usually has more than just joint involvement, according to the 2009 Pediatric Rheumatology article by Dr. Kristin Houghton of the Children's Hospital in Vancouver, Canada. Systemic JIA is associated with fevers and a rash along with joint pain, while other subtypes of JIA can present only with joint involvement. Eye inflammation can occur in JIA and can lead to vision loss if not treated. Patients usually have morning stiffness along with painful and decreased range of motion of the affected joints. Treatments can range from non-steroidal anti-inflammatory drugs and physical therapy to methotrexate (a chemotherapeutic agent) to monoclonal antibody treatments directed at specific inflammatory markers. It is important to see a rheumatologist for treatment and follow-up.
Reactive arthritis is an immunologic condition that typically occurs after another infection. Patients typically carry the HLA-B27 antigen; however, this is not required to have the condition. The condition typically is not chronic; however, it can be more likely if associated with the HLA-B27 positive patient. Treatments are similar to those for JIA.
Conditions such as ulcerative colitis and psoriasis can be associated with joint manifestations of arthritis. These typically present with symptoms of arthritis along with symptoms of the underlying disease, gastrointestinal symptoms or skin findings.
Common in the northeast United States is Lyme disease caused by a rheumatologic reaction to the bacteria Borrelia burgdoferi. Lyme disease is transferred to the human by a tick bite. Lyme disease can cause a plethora of symptoms ranging from meningitis to "bulls-eye" rash. Usually there is no active Borrelia burgoferi bacteria in the affected joint and it is more of an inflammatory reaction. Treatment is with antibiotics and symptom relief for the joint.
Transient Synovitis
Transient synovitis (toxic synovitis) is a common pediatric condition that involves joint pain thought to occur presumably after a recent viral illness or trauma. It is generally self-limiting. The hip joint commonly is painful to move and the patient may have a limp. The age of the patients is usually 3 to 8 years. The diagnosis is made after excluding more destructive causes including septic joint and Legg-Calve-Perthes disease. Treatment involves rest, non-weightbearing on the affected leg and non-steroidal anti-inflammatory medications.
Legg-Calve-Perthes Disease (LCP)
Legg-Calve-Perthes disease is a form of osteonecrosis/avascular necrosis. Osteonecrosis/avascular necrosis refers to a condition where there is inadequate blood supply to a bone, resulting in death of bone cells. The reason for LCP is unknown. LCP is usually found in children between the ages of 3 to 12. Altered gait (walking with a limp) and pain are typically the presenting symptoms. Younger children typically have better outcomes. There are specific findings on x-ray showing destruction/fragmentation of the femoral head earlier in the disease and then healing. The healing process can form a distinct appearance of the femoral neck and lead to chronic pain from altered joint articulation. Initial treatment involves splinting with non-weight bearing on the affected side. It is important to see a pediatric orthopedic surgeon for definitive management.
Slipped Capital Femoral Epiphysis (SCFE)
Slipped capital femoral epiphysis (SCFE) is a condition of the growth plate where there is displacement of the bone fragments on each side of the growth plate on the proximal femur (closest to the hip joint). It is most common in obese adolescent boys. Patients typically have hip, groin or knee pain along with a limp. There is an irregularity at the growth plate on x-ray. Treatment is aimed at stabilizing the bone usually through surgical fixation of the bones with screws.
Oncologic/Malignancy
Both benign and malignant tumors of the bone can lead to pain in the hip and groin. A common site for an osteoid osteoma tumor is the portion of the femur near the hip joint (proximal femur). It is most often seen in teenagers and is a benign tumor with symptoms that respond to non-steroidal anti-inflammatory medication.
Malignancies such as leukemia, lymphoma and neuroblastoma can also present as bone pain. Ewing sarcoma is a pediatric bone tumor that is very aggressive. Basic x-rays, CT scans and MRIs can help find and differentiate these tumors, which require special treatments by a variety of specialists.
Congenital, Trauma and Referred Pain Conditions
Active pediatric patients can have a plethora of muscle strains in the hips, groin, thighs or hamstrings. Fractures are always possible with any trauma. Fractures can cause acute pain or chronic pain states even when adequately treated. Stress fractures tend to occur more commonly in athletes who repetitively put loads on the bones from activities such as running. Patients with altered eating habits such as anorexia tend to develop stress fractures more commonly.
Snapping hip syndrome refers to a condition where there is clicking/snapping with hip movement that can occur along with pain. It is intimately related to the bursa either over the outside of the hip (trochanteric bursa) or the internal bursa (iliopsoas bursa). The mainstay of treatment is physical therapy.
Hip pain can also be referred from other structures including from the spine or from internal abdominal organs. True inguinal hernias and sports hernias can be causes of hip/groin discomfort.
Developmental dysplasia of the hip (DDH) is a condition of an unstable joint due to improper formation of the joint. It is usually diagnosed and treated early in infancy; however, patients can have residual pain throughout childhood.
