S Kamath, D Bramley
Monklands Hospital, Airdrie, Lanarkshire
Correspondence to: Mr S Kamath FRCS, 54 Barony Court, Nantwich, Cheshire CW5 5RD Tel: 01270 629 715 Email:hskamath5@hotmail.com (Present location Dept of Orthopaedics, Leighton Hospital, Crewe)
SMJ 2005 50(2): 56-58
Abstract
Background: The role of the ‘clicky hip’ symptom as a prognostic predictor of developmental dysplasia of hip (DDH) is controversial. We aim to study the role of isolated hip clicks as a prognostic predictor of DDH. Material and methods: 235 babies with persisting or referred with clicky hip beyond six weeks of age were prospectively followed up to note the incidence of DDH. Of these 176 babies were referred for a hip click without additional risk factors. Results: 7 out of 176 cases (4 – IIa, 2 – IIb, 1 – IIc) had initial abnormal ultrasound examination based on Graf classification. However, all babies with isolated hip clicks eventually had normal hips on clinical and radiographic examination. Discussion: While screening of babies with clicky hips does help in diagnosing the odd case of DDH this is not consistently reproducible. Modifying the targeted ultrasound screening by including clicky hip as a risk factor will not reduce the incidence of missed cases. Isolated clicks in the hip joint beyond six weeks age are rarely a predictor of DDH. However when in doubt such cases should be referred to be reviewed by an orthopaedic surgeon or a radiologist experienced in hip ultrasound.
Key words: Clicky hip, DDH, CDH, risk factors
Introduction
Clickiness in the hip joint has been associated with developmental dysplasia of the hip (DDH), though the prognostic importance of the 'click' in relation to hip instability remains controversial.1,2,3,4,56 The study examined the incidence of DDH in babies referred with an isolated clicky hip and compared this with the incidence of DDH in babies having a clicky hip with other associated risk factors. We aim to study the role of isolated hip clicks as a prognostic predictor of DDH.
Material and methods
In the period between August 2001 and December 2003, as part of routine child health surveillance, primary care physicians or paediatricians referred 235 babies with clicking hips noted at six weeks postnatal check or afterwards. Fortytwo babies had bilateral, 62 had right sided and 131 babies had left hip clicks. All cases, irrespective of their age at the time of referral, are seen in our institute and have clinical and ultrasound examination. Children referred with a clicky hip within first six weeks of birth were not included in our study as clickiness is associated with physiologically immature hips at this age and these almost always spontaneously normalize without treatment.3
Children who had persisting hip clicks at their six weeks post natal assessment or who were referred with clicky hips at a later date were reviewed. The median age at the time of initial examination was 18 weeks (6 – 60 weeks). The male to female ratio was 1:2.6. One hundred and twenty children were first born. Of the 235 babies, 17 were breech presentation and 25 babies had positive family history. Thirty-four babies were delivered by caesarian section of which 17 babies had the caesarian section for reasons other than breech presentation. Therefore, a total of 176 babies were referred for a hip click, without additional risk factors. All except nine cases had static ultrasound examination of both hips, the results of which were classified as described by Graf. 7 Nine cases were aged six months and above at the time of referral and thus had radiographic evaluation of the hips.
Results
Of the 176 babies referred with an isolated clicky hip, physical examination was normal with stable hips. Static ultrasound examination was carried out in 167 cases of which 160 cases were normal, based on the Graf classification. Four hips were grade IIa, two hips were grade IIb and one hip had grade IIc changes on initial examination. (Table I) However, all cases at six month follow up had progressed to a normal hip, as confirmed by radiographs. Nine cases, referred after six months age, were normal on radiographic examination.
All the cases with initial normal ultrasound examination were seen again when the child was one year old or after they had started walking, whichever was the earliest and had clinical and radiographic examination if needed at that time. Children with initial abnormal ultrasound examination were followed up at more regular intervals for one year or beyond till both capital femoral epiphysis were fully developed and well medialised with symmetrical acetabular indices. None of the cases in our series referred with clicky hips subsequently developed DDH. Of the 59 babies with other associated risk factors, 50 had normal clinical and ultrasound examination. Four hips had grade IIa, two hips had grade IIb and one hip had grade IIc on initial ultrasound. All subsequently progressed to normal hips at follow up examination.
One baby with an associated breech presentation and one baby with a positive family history had a clinically unstable hip which was classified as Graf III on initial ultrasound. These required treatment.
Discussion
Soft tissue clicks are common, being reported in about 10% of newborns, and usually resolve with time.1 The ‘click' is usually of little consequence and may represent either a transient vacuum phenomenon within the joint or muscle or tendon snapping.2 Many articles state that an isolated click without other clinical signs of instability is insignificant and is not a sign of DDH.2,3,5 However, some authors believe that a click is an important sign that requires systematic follow up.1,4,6 In our prospective series of 176 cases with isolated hip clicks, seven cases had initial abnormal ultrasound examination. However, all babies with isolated hip clicks eventually had normal hips on clinical and radiographic examination. Two of the 59 cases of clicky hips with other associated risk factors showed abnormal hip necessitating treatment.
In our experience, a clicky hip has been the most common reason for referral to the hip-screening clinic. Clicky hip is a vague term and most often the terminology is used by inexperienced referring physicians. The real problem is that paediatricians and primary health care workers can use the term clicky to mean ‘abnormal’/ unstable/dislocated as well as for ligamentous clicks. They should be encouraged to be specific and say exactly what they found on examination - abnormal groin creases, short leg, restricted abduction, Barlow positive, Ortolani positive, fixed dislocation or ligamentous click. All such cases should initially be examined by an experienced primary care physician. While screening of babies with clicky hips may help in diagnosing the odd case of DDH this is not consistently reproducible. Hip clicks in babies less than six weeks of age are often associated with physiologic immaturity. Modifying the targeted ultrasound screening to include the clicky hip as a risk factor will not significantly reduce the incidence of missed cases.
Isolated clicks in the hip joint beyond six weeks age are rarely a predictor of DDH. However when in doubt such cases should be referred to be reviewed by an orthopaedic surgeon or a radiologist experienced in hip ultrasound.
REFERENCES
1 Allan DB, Gray RH, Scott TD, Tonkin M, Hughes JR, Evans GA. The relationship of ligamentous clicks arising from the newborn hip and congenital dislocation. J Bone Joint Surg [Br] 1985;67-B:491.
2 Benson MKD, Fixsen JA, Macnicol MF. Children’s orthopaedics and Fractures. Churchill Livingstone 1994; 420.
3 Bond CD, Hennrikus WL, DellaMaggiore ED. Prospective evaluation of newborn soft tissue hip clicks with ultrasound. J Pediatr Orthop 1997;17:199- 201.
4 Cunningham KT, Moulton A, Benningfield SA, Maddock CR. A clicking hip in a newborn baby should never be ignored. Lancet 1984;3:668-70.
5 Dunn PM. Clicking hips should be ignored. [Letter] Lancet 1984;1:846.
6 Jones DA. Importance of the clicking hip in screening for congenital dislocation of the hip. Lancet 1989;8638:599-601.
7 Graf R. The diagnosis of congenital hip-joint dislocation by the ultrasound combound treatment. Arch Orthop Trauma Surg 1980;97:117–33.