Paeds- hip problems Flashcards
Developmental Dysplasia of the Hip (DDH)
dislocation or subluxation of the femoral head during the perinatal period which affects the subsequent development of the hip joint.
It affects up to 5 in 1000 babies and girls are more commonly affected than boys accounting for 80% of cases.
It is more common in the left hip (due to intrauterine position?) but in 20% of cases is bilateral.
DDH risk factors
positive family history of DDH, breech presentation, first born babies, Down’s syndrome and the presence of other congenital disorders (talipes, arthrogryposis).
DDH if left untreated
the acetabulum is very shallow and in more severe cases a false acetabulum occurs proximal to the original one with a shortnened lower limb.
Severe arthritis due to reduced contact area can occur at a young age and gait / mobility may be severely affected.
DDH signs
include shortening, asymmetric groin/thigh skin creases and a click or clunk on the Ortolani or Barlow manoeuvres.
DDH investigation
Unstable hips with a positive Ortolani test (reducing a dislocated hip with abduction and anterior displacement)
Barlow test (dislocatable hip with flexion and posterior displacement) require further evaluation with ultrasound
USS should detect a dislocated hip, an unstable hip or a shallow acetabulum. which should detect a dislocated hip, an unstable hip or a shallow acetabulum.
Xrays cannot be used for the early diagnosis of DDH as the femoral head epiphysis is unossified until around 4‐6 months but xrays are the investigation of choice after this age.
DDH diagnosis & treatment
Early diagnosis is key to the success rates of treatment.
Mild cases with a slightly shallow acetabulum and mildly dislocatable but reduced (in joint) hip can be closely observed with serial examination and ultrasound to ensure the hip remains reduced.
Dislocated or persistently unstable hips are reduced and held with a special harness known as a Pavlik harness which keeps the hips in comfortable flexion and abduction thus maintaining reduction (over‐flexing and abducting the hip can result in avascular necrosis).
The Pavlik harness is used full‐time for around 6 weeks and part‐time for a further 6 weeks once the hip is confirmed to be stable. A Pavlik harness can be used up to around 4‐6 months of age and the success rate is 85‐95%.
For children with persistent dislocation over 18 months old open reduction is much more likely to be required and the acetabulum is likely to be very shallow by this stage.
Typically the child will need an open reduction to clear soft tissues and may also need an osteotomy to shorten and rotate the femur and/or pelvic osteotomy to deepen and re‐orientate the acetabulum.
Persistent or undiagnosed DDH at this stage tends to have a poorer prognosis.
Transient synovitis
a self‐limiting inflammation of the synovium of a joint, most commonly the hip.
It commonly occurs shortly after an upper respiratory tract infection (usually viral) although sometimes no cause is found.
Typical age is between 2 and 10 and boys are more commonly affected than girls.
Transient synovitis presentation & symps
commonest cause of hip pain in childhood although other pathologies including septic arthritis
Perthes disease
Juvenile Idiopathic Arthritis
Rheumatoid arthritis must to be excluded.
Presentation is with limp or reluctance to weight bear on the affected side.
Range of motion may be restricted (but not as much pain or loss of motion as septic arthritis).
The child may have a low grade fever but is not systemically unwell or septic.
Transient synovitis investigation
Radiographs can exclude Perthes disease whilst a normal or near normal CRP and a clinical picture more suggestive of transient synovitis may exclude septic arthritis.
If there is any doubt aspiration of the hip under anaesthetic or open surgical drainage may be performed to limit cartilage damage from potential bacterial infection.
MRI may also be useful in equivocal cases as osteomyelitis of the proximal femur is a further possible diagnosis.
Transient synovitis treatment
a short course of NSAIDs and rest. Pain generally resolves within a few weeks but if there is no resolution then another cause for hip pain (JIA, early Perthes) should be sought.
Perthes disease
(aka Legg‐Calve‐Perthes disease) is an idiopathic osteochondritis of the femoral head which usually occurs between the ages of 4 to 9 and is more common in boys (around 5:1), particularly very active boys of short stature.
The femoral head transiently loses its blood supply resulting in necrosis with subsequent abnormal growth. The femoral head may collapse of fracture.
Subsequent remodeling occurs however the shape of the femoral head and congruence of the joint is determined by age of onset (with older children faring worse) and the amount of collapse.
In incongruent joint will lead to early onset of arthritis and severe cases may require hip replacement in adolescence or early adulthood.
Perthes disease symptoms & investigation
Affected children present with pain and a limp.
Most cases are unilateral and bilateral cases may represent an underlying skeletal dysplasia or a thrombophilia.
Loss of internal rotation is usually the first clinical sign followed by loss of abduction and later on a positive Trendellenburg test from gluteal weakness.
Perthes disease treatment
no specific treatment other than regular xray observation and avoidance of physical activity.
Approximately 50% of cases do well. In some cases the femoral head becomes aspherical, flattened and widened.
The lever arm of the abductor muscles is altered resulting in weakness (Trendellenburg positive).
Occasionally the femoral head may sublux (partially dislocate) requiring an osteotomy of the femur or acetabulum.
SUFE – Slipped Upper Femoralase may predispose to SUFE.
mainly affecting overweight pre‐pubertal adolescent boys where the femoral head epiphysis slips inferiorly in relation to the femoral neck.
girls are less commonly affected and hypothyroidism or renal disease
the growth plate (physis) is not strong enough to support body weight and the femoral epiphysis slips due to the strain.
growth spurt may preclude the onset and puberty may be delayed (idiopathic or hypothyroidism). 1/3 of cases are bilateral.
Slipped Upper Femoral Epiphysis signs & symptoms
Cases can be acute (sudden onset), chronic or acute‐on‐chronic.
Patients have pain and a limp.
The pain may be felt in the groin (like other hip pathology) however the major pitfall is that patients can present purely with pain in the knee (due to the obturator nerve supplying both the hip and knee joint) and the diagnosis can be missed as an unwary clinician may fail to examine the hip, concentrating solely on the knee and treat as a benign knee condition.
