Paeds · rheumatology-musculoskeletal-and-sports
Transient synovitis and the irritable hip
Also known as irritable hip · transient synovitis · toxic synovitis · observation hip · coxitis fugax
A fellowship approach to the child with an irritable hip: transient synovitis as the commonest benign cause of acute limp, the Kocher clinical prediction rule that separates it from septic arthritis at the bedside, the ultrasound effusion and the inflammatory markers that frame the decision, and the watchful waiting with rest and a non-steroidal anti-inflammatory drug that resolves the limp within one to two weeks once pus has been excluded.
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- Never call an irritable hip transient synovitis until you have excluded septic arthritis — apply the Kocher criteria and the inflammatory markers first, because a child with two or more predictors carries a roughly forty per cent or higher probability of pus in the joint that will not wait for the morning
- A febrile child who refuses to bear weight at all, with raised inflammatory markers, is septic arthritis until proven otherwise — the preceding viral illness does not make this transient synovitis, and the refusal to walk is the loudest bedside clue
- An afebrile well-looking child who still limps may have early Perthes disease or a stress fracture mislabelled as transient synovitis — a limp that persists beyond two weeks demands repeat imaging, because transient synovitis resolves and the mimics declare themselves by not resolving
- Kingella kingae septic arthritis in the under-four mimics transient synovitis with a low fever and modestly raised markers — a culture-negative effusion in this age group is not reassuring, and blood-culture-bottle inoculation or polymerase chain reaction is required
- A recurrent irritable hip is not simply a second episode of transient synovitis — recurrent effusion in the same hip raises the possibility of juvenile idiopathic arthritis, early Perthes disease, or an underlying structural lesion, and it warrants specialist review and repeat imaging
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- Musculoskeletal medicine - evaluate the limping child and the irritable hip
- Acute presentations - differentiating transient synovitis from septic arthritis
- Renewed curriculum for first-year trainees from 2027 - Learning goal 6: Clinical management - essential general paediatrics
- Rheumatology and orthopaedics - apply the Kocher criteria to the irritable hip and decide who to aspirate
- Acute presentations - the febrile limping child and the risk of misdiagnosis
- Orthopaedics - recognise Perthes disease and slipped capital femoral epiphysis as mimics
- Musculoskeletal 10-12
- Acute presentations 10-12
- Clinical Applications
- Short Cases
- Long Cases
- 9. Musculoskeletal medicine - the limping child and the irritable hip
- 11. Child health (urogenital and MSK) - safe use of imaging and analgesia
- 4. Professional skills and knowledge: Patient management
- Foundation of Practice (FOP)
- Theory and Science (TAS)
- Applied Knowledge in Practice (AKP)
- Clinical
- History
- Communication
- Video
- General Pediatrics Content Outline - Musculoskeletal disorders
- General Pediatrics Content Outline - Universal Task 3: Diagnostic reasoning
- General Pediatrics Content Outline - Infectious Diseases
- Patient Care 4: Clinical Reasoning
- Patient Care 5: Patient Management
- Medical Knowledge 1: Musculoskeletal disorders and infectious diseases
- Medical Expert
- Pediatrics: Foundations EPA - Acute care of the limping child
- Pediatrics: Rheumatology and orthopaedics applied domain
A five-year-old boy is brought to the emergency department with a one-day limp and a sore right hip, two days after a runny nose; he is afebrile, he walks cautiously but he walks, his inflammatory markers are normal, and the ultrasound shows a small hip effusion. Or an eight-year-old girl limps after school with a stiff hip and a recent cough, and the question is whether to send her home or to tap the joint. In each, the move is the same — score the probability of sepsis, exclude the mimics, and only then call it transient synovitis. [6] [9]
Work the irritable hip as four moves. Score the probability of sepsis with the Kocher criteria — fever over thirty-eight point five, unable to bear weight, ESR over forty, white cell count over twelve — and add CRP over twenty from the Caird study. Scan with ultrasound to confirm a hip effusion and to exclude the mimics. Sample-if the joint when the probability is two or more predictors or the clinical picture is septic, because aspiration is the only way to exclude pus. Soothe with rest and a non-steroidal anti-inflammatory drug once pus is excluded, and the limp resolves within one to two weeks. [1] [3]
Overview & Definition
The irritable hip is the clinical syndrome of a painful, stiff hip in a child who limps or refuses to walk, and transient synovitis is its commonest and most benign cause — a self-limiting, non-infectious inflammation of the hip synovium that resolves without sequelae. The two terms travel together because the bedside problem is the stiff, painful hip, and the diagnostic work is to separate the harmless transient synovitis from the dangerous septic arthritis, the surgical Perthes, and the structural slipped capital femoral epiphysis. [6] [9]
The fellowship framing rests on a single diagnostic truth. Transient synovitis is a diagnosis of exclusion, made only once septic arthritis has been ruled out by the Kocher clinical prediction rule, the inflammatory markers, and — when the probability is high — the synovial fluid. The pathology is a transient, reactive inflammation of the synovium, often following a viral upper respiratory infection, that produces a small effusion, a stiff hip, and a limp, and that resolves spontaneously over one to two weeks without antibiotics, without surgery, and without permanent damage. [1] [7]
The clinical importance comes from what happens when the exclusion is skipped. A child with septic arthritis mislabelled as transient synovitis loses the window for drainage, and the intracapsular pus destroys the cartilage and the femoral head blood supply within hours. A child with early Perthes mislabelled as transient synovitis loses the chance for early imaging and containment planning. The safeguard is the discipline of scoring the probability of sepsis before reassuring anyone, and of reviewing the child whose limp does not resolve within the expected window. [4] [9]
References11ShowHide
- [1]Kocher MS, Zurakowski D, Kasser JR. Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm. J Bone Joint Surg Am, 1999.PMID 10608376
- [2]Kocher MS, Mandiga R, Zurakowski D, Barnewolt C, Kasser JR. Validation of a clinical prediction rule for the differentiation between septic arthritis and transient synovitis of the hip in children. J Bone Joint Surg Am, 2004.PMID 15292409
- [3]Caird MS, Flynn JM, Leung YL, Millman JE, D'Italia JG, Dormans JP. Factors distinguishing septic arthritis from transient synovitis of the hip in children. A prospective study. J Bone Joint Surg Am, 2006.PMID 16757758
- [4]Lipshaw MJ, Walsh PS. Transient synovitis of the hip: Current practice and risk of misdiagnosis. Am J Emerg Med, 2022.PMID 35994972
- [5]Benoit J, El Khalifi S, Saoudi C, et al. Transient synovitis of the hip: Development and validation of a new diagnostic algorithm. Acta Paediatr, 2024.PMID 38366676
- [6]Nouri A, Walmsley D, Pruszczynski B, Synder M. Transient synovitis of the hip: a comprehensive review. J Pediatr Orthop B, 2014.PMID 23812087
- [7]Dubois-Ferrière V, Belaieff W, Lascombes P, et al. Transient synovitis of the hip: which investigations are truly useful?. Swiss Med Wkly, 2015.PMID 26295841
- [8]Yagupsky P, Dubnov-Raz G, Gené A, et al. Differentiating Kingella kingae septic arthritis of the hip from transient synovitis in young children. J Pediatr, 2014.PMID 25217199
- [9]Ryan DD. Differentiating Transient Synovitis of the Hip from More Urgent Conditions. Pediatr Ann, 2016.PMID 27294495
- [10]Yang WJ, Im SA, Lim GY, et al. MR imaging of transient synovitis: differentiation from septic arthritis. Pediatr Radiol, 2006.PMID 17019590
- [11]Martinoli C, Garello I, Marchetti A, et al. Hip ultrasound. Eur J Radiol, 2012.PMID 21571471