Hip pain in children
- The most common causes of hip pain in children are synovitis of the hip, Perthes disease and slipped capital femoral epiphysis.
- Rarer serious aetiologies of hip pain are leukaemia, juvenile arthritis  and enteropathic reactive arthritis . These aetiologies are not addressed in this article.
Synovitis of the hip
Signs and symptoms
- The most common cause of a sudden limp and refusal to walk in children between 3 and 10 years of age.
- This is an acute aseptic inflammation of the synovial membrane of the hip.
- The child complains of severe pain in the hip, thigh or knee, and holds the thigh in a flexed position and externally rotated with the knee bent. Hip rotation and extension are limited.
- ESR may be slightly elevated.
- An ultrasound examination of the hip will reveal possible effusion in the hip joint.
- Even though radiographic findings will be normal, x-rays are indicated particularly when the symptoms persist or the clinical picture is atypical and always when the patient is older than 10 years.
- Another diagnosis is likely (and referral to a specialist warranted) if
- the symptoms have persisted for longer than two weeks
- the patient is under 2 or over 10 years of age
- the patient is febrile or
- CRP is higher than 20 mg/l or ESR higher than 35 mm/t.
- Differential diagnoses include, in particular, Perthes disease, slipped capital femoral epiphysis, septic arthritis, osteomyelitis, juvenile arthritis , osteoid osteoma and neoplasias.
- Synovitis of the hip is sometimes bilateral, but if other joints are involved the child has a different disease.
- If it is possible to exclude other conditions with certainty, the entire treatment can be carried out in primary health care.
- Treatment consists of rest; the child should be allowed to keep the hip in the most comfortable position.
- Pain may sometimes be severe. Symptomatic treatment consists of anti-inflammatory drugs or paracetamol .
- Diagnostic arthrocentesis (requires general anaesthesia) may be necessary to exclude bacterial infection.
- Prognosis is good even without treatment.
Prevalence and symptoms
- Osteonecrosis of unknown aetiology involving the epiphysis of the femoral head, which may cause a symptomatic subchondral stress fracture. The fracture and delayed ossification of the femoral head cartilage will lead to the softening of the epiphysis which, in turn, may cause permanent flattening of the femoral head.
- Usually affects boys between 5 and 9 years of age (boys:girls = 4:1).
- In 10% of patients, the disease is bilateral but does not usually affect both sides at the same time.
- The main symptom is a limping gait. The clinical picture is similar to that of synovitis of the hip, but the symptom onset is usually gradual, and the symptoms are persistent or recurring.
- The pain is often limited to the area between the groin and knee.
- ESR, CRP and leukocyte count are normal.
Treatment, follow-up and prognosis
- The aim should be to diagnose Perthes disease early.
- Diagnosis is based on x-rays: irregularity of the subchondral bone structure and widening of the joint space is noted initially followed by flattening of the epiphysis. The unaffected hip should also be x-rayed for comparison.
- A suspicion of Perthes disease is an indication for referral to an orthopaedic or paediatric surgeon within a few weeks.
- An MRI scan may be indicated in unclear cases.
- The aim of treatment is to correct subluxation and contain the femoral head within the confines of the acetabulum in order to return the spherical shape to the softened and flattened cartilaginous head of the femur.
- This can be achieved either by using an abduction brace or through femoral or pelvic (or both) osteotomy.
- Reduced range of motion (particularly abduction of less than 30º with the hip extended or passive hip rotation to abduction when applying flexion to the thigh) and radiological subluxation are suggestive of significant deformity of the femoral head.
- Arthrography under general anaesthesia may be indicated in order to establish the aetiology of reduced range of motion and to plan the possible surgical intervention. MRI scanning is indicated only in special cases.
- All hips affected by Perthes disease must be closely monitored in the acute phase. The monitoring consists of a physical examination and x-rays every three months.
- Prognosis is usually good for young children (under 6 years) and no specific treatment is needed.
- The disease duration is 2–4 years, depending on the age of the patient.
Slipped capital femoral epiphysis (epiphyseolysis capitis femoris)
Incidence and symptoms
- Slipped capital femoral epiphysis (SCFE), also called slipped upper femoral epiphysis (SUFE) and epiphysiolysis of the hip, is characterised by a displacement of the femoral epiphysis in relation to the femoral neck.
- The condition is defined as stable if metaphyseal remodelling has occurred after the slippage, and the epiphysis is fixed in a new position. The patient is able to walk. If remodelling has not yet occurred the condition is considered to be unstable. An unstable SCFE is very painful.
- Early diagnosis and surgical treatment should be pursued. If left untreated the medial and posterior shift of the epiphysis will increase and further worsen the functioning of the hip. In moderate to severe cases the risk of osteoarthritis is increased.
- Occurs at the age of 10–16 years (somewhat earlier in girls), often in association with obesity (boys:girls = 2.5:1).
- Bilateral involvement is seen in 20–30% of patients.
- The clinical signs will always include a limp and decreased range of motion.
- The severity of pain varies greatly; from a painless condition up to pain-induced inability to walk. Pain in the knee, thigh and inguinal area, on weight bearing and during movement, is typical. Pain radiating to the knee may be misleading when attempting to localise the origin of pain.
- The patient usually holds the lower limb in slight external rotation.
- If SCFE is suspected (typical age and hip joint symptoms) both anterioposterior and Lauenstein projections of both hips should be taken without delay. Posterior displacement of the epiphysis will be evident in the x-rays.
- In a recently slipped epiphysis, the physeal step is clearly identifiable by ultrasonography. If there is sonographic evidence of joint effusion, the condition can be considered unstable.
- The patient warrants emergency referral to an orthopaedic specialist.
- The treatment is always surgical. Percutaneous fixing with a single screw is used to stabilise the epiphysis. The smaller the displacement the better the outcome in most cases. In severe displacement, osteotomy of the femoral neck or trochanter may be indicated.
- Prophylactic fixation of the contralateral asyptomatic hip should be considered if the patient is very young or has an endocrinological or metabolic underlying disease (about 7% of cases).
Ischiopubic synchondrosis (van Neck osteochondrosis)
- The pelvic bones develop from cartilaginous structures which gradually ossify to form a continuous hip bone. The ischiopubic synchondrosis is a cartilaginous joint, occurring prior to the final fusion of the ischial and pubic bones. The ossification of this cartilaginous joint can be a painful process.
- A rare cause of a painful limp
- Encountered in children aged between 6 and 10 years.
- The symptoms persist for a few months, and recovery is spontaneous.
- It is important that other conditions are excluded by an orthopaedic specialist.
- Plain pelvic x-rays, and sometimes an MRI scan, are indicated.
- Restriction of sporting activities should be considered as needed.
Strain-induced osteochondroses of the hip
- These conditions occur during the pubertal growth spurt, sometimes earlier.
- They affect the attachment sites of large muscles, which are cartilaginous structures in children.
- Analogous with Osgood–Schlatter disease in the knee.
- The typical locations are:
- the posterior thigh muscle attachment site at the ischial tuberosity
- in the front of the pelvis, the sartorius muscle attachment site at the anterior superior iliac spine
- in the front of the hip, the rectus femoris muscle attachment site at the anterior inferior iliac spine
- in the groin, the iliopsoas muscle attachment site in the lesser trochanter.
- A careful clinical examination is important. X-rays are mainly used for excluding other conditions.
- Treatment is symptomatic and can be carried out in primary health care.
- Sporting activities that induce pain should be stopped for a fixed period.
- Apophysitis of the ischial tuberosity, in particular, may warrant a break of up to 6 months from running and jumping.
1. Kermond S, Fink M, Graham K, Carlin JB, Barnett P. A randomized clinical trial: should the child with transient synovitis of the hip be treated with nonsteroidal anti-inflammatory drugs? Ann Emerg Med 2002 Sep;40(3):294-9. [PMID:12192353].
Copyright © 2010 Duodecim Medical Publications Limited.
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