Diagnostic algorithm

The following four-pillar clinical framework is a practical way to assess diagnostic concordance and select candidates for hip arthroscopy: compatible history, examination findings, concordant imaging, and response to an intra-articular injection.

Pillar	Question	Supportive pattern
1. Typical history	Does the pain story fit a hip-related problem?	Activity-related, mechanically provoked anterior/groin pain with a coherent functional limitation. Think C-sign pain.
2. Examination	Can you reproduce familiar pain and identify the relevant impairment?	FADIR/FABER or loading test reproduces familiar pain; ROM/strength/stability findings fit the story.
3. Imaging	Does imaging show a plausible structural correlate?	Radiographs and advanced imaging showing FAI bony morphology or soft-tissue damage.
4. Injection	Does intra-articular anesthetic relief support an intrarticular pain source?	Meaningful improvement in the familiar pain during a documented anesthetic window.

This framework aligns with the Warwick definition of FAIS: symptoms, clinical signs, and imaging findings must coexist.

Diagnostic concordance:

Confirm a hip-related history and rule out red flags or a dominant non-hip source.
Perform a complete hip and regional examination, document familiar pain and competing pain generators.
Obtain appropriate radiographs and advanced imaging when indicated. Assess morphology, joint preservation, and alternative diagnoses.
Perform a diagnostic injection if needed to clarify the diagnosis.
If the pillars agree, discuss the diagnosis and treatment options. If they conflict, re-examine and consider other diagnoses.

Diagnostic concordance increases as the four pillars converge. When one pillar is markedly discordant, particularly the history or injection response, an imaging finding should not carry the entire decision.

Diagnostic algorithm

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