12-phase flow (12)

1. 1FRAME
   Shoulder pain is a region, not a diagnosis; phenotype-first; the rotator-cuff spectrum (tendinopathy → partial → full tear) dominates, with adhesive capsulitis / instability / AC-OA / calcific / referred as the MECE alternatives (JOSPT 2022 Lafrance)
   inputs: age, symptom_duration_band
   advance: Scope framed: cuff-spectrum-dominant region with MECE phenotype alternatives
2. 2ENTRY
   Lateral pain worse overhead; painful arc ± weakness; progressive global stiffness; instability event; acute trauma then sudden weakness; chronic-pain review (JOSPT 2022 Lafrance; AAOS 2019; UK FROST Rangan 2020)
   inputs: age
   advance: Engine entered via a recognised trigger
3. 3CONTEXT
   Pre-test prior is CONDITIONED (Bayesian §5.5.2), not a single number. CUFF-TEAR PRIOR | age × trauma band: atraumatic full-thickness cuff prevalence ~6–10% if <60 y, ~25–30% if 60–70 y, >30–50% if >70 y (often asymptomatic — Yamamoto/Minagawa cohorts in JOSPT 2022 Lafrance); a discrete trauma event (FOOSH / forced abduction) in a <60 y active patient shifts prior toward an ACUTE full-thickness tear (the surgical window) — so the SAME positive lag sign carries a far higher post-test probability in the elderly or post-trauma than in a young atraumatic patient. CAPSULITIS PRIOR | diabetes: baseline frozen-shoulder prevalence ~2–5% rises to ~13% with diabetes (pooled OR ~5; Zreik PMID 27331029) — the passive-ER-loss pivot LR is interpreted against the diabetic-conditioned prior, not the general prior. INSTABILITY PRIOR | age × sport: <25 y contact-sport markedly raises post-dislocation recurrence prior (AAOS 2019). Capture hand-dominance / overhead occupation / athlete, smoking, CKD/GI/CVD for NSAID gating, neck symptoms (referred-source prior) (JOSPT 2022 Lafrance; Zreik PMID 27331029; AAOS 2019)
   inputs: age, diabetes_or_thyroid, ckd_gi_cvd_status, symptom_duration_band
   advance: Conditioned pre-test prior (cuff-tear|age×trauma, capsulitis|diabetes, instability|age×sport) + driver + comorbidity profile captured
4. 4RED_FLAGS
   ACUTE TRAUMATIC FULL-THICKNESS TEAR in a younger active patient = time-critical surgical window (expedite referral); septic glenohumeral joint (fever + hot swollen joint → aspiration); malignancy / Pancoast (night pain, weight loss, smoking, fixed mass); Parsonage-Turner (severe pain → patchy weakness after viral/immunisation prodrome); unreduced dislocation; vascular (axillary/subclavian — pulse/colour); REFERRED — cervical radiculopathy (Spurling+, dermatomal), cardiac ischaemia, diaphragmatic/sub-diaphragmatic (JOSPT 2022 Lafrance; AAOS 2019)
   inputs: trauma_mechanism, fever_or_systemic_features, neuro_or_referred_features
   actions: panel.inflammation
   advance: Surgical-window tear, septic, malignancy, neuro, vascular and referred causes screened and escalated if present
5. 5INITIAL_WORKUP
   Clinical exam is primary; the cluster LR is computed with CONDITIONAL DEPENDENCE, not as the naive product of singles (shared impingement/cuff mechanism inflates a multiplied LR). SINGLES (LR derived from pooled sens/spec): Neer sens 0.79 / spec 0.53 → LR+ 1.68, LR− 0.40 (Hegedus 2008 PMID 17720798); Hawkins sens 0.79 / spec 0.59 → LR+ 1.93, LR− 0.36 (Hegedus 2008); painful arc sens 0.97 / spec 0.05 (acute FT cohort) → LR+ 1.02, LR− 0.59 — pure rule-out anchor (Bak 2010 PMID 20511030); empty-can/Jobe sens ~0.69 / spec ~0.62 → LR+ 1.82, LR− 0.50 (Hegedus 2012 PMID 18996735); supraspinatus test (any FT tear) DOR 9.24, sens 0.74 / spec 0.77 → LR+ 3.22, LR− 0.34 (Gismervik 2017 PMID 28122541); external-rotation lag sign (acute FT supraspinatus) sens 0.39 / spec 0.91 → LR+ 4.33, LR− 0.67 (Bak 2010 PMID 20511030); drop-arm sens 0.37 / spec 0.86 → LR+ 2.64, LR− 0.73 (Bak 2010); modified Neer spec 0.956 → LR+ ~high rule-IN (Naqvi 2023 PMID 37051997); supraspinatus palpation sens 0.92 → strong rule-OUT (Naqvi 2023); Speed sens 0.32 / spec 0.61 → LR+ 0.82 (poor, Hegedus 2008); belly-press/lift-off/bear-hug composite for subscapularis sens 0.81 (Faruqui 2014 PMID 24683653). VALIDATED CLUSTERS (post-test from a defined prior — NOT a product): Park 2005 (PMID 15995110) Hawkins+painful-arc+infraspinatus → post-test 95% for any impingement; painful-arc+drop-arm+infraspinatus → post-test 91% for a FULL-THICKNESS tear. STRONGEST WIRED COMPOSITE: Gwark & Park 2019 (PMID 31699076) multivariable model age ≥67 + subscapularis tear + Patte retraction ≥2 + hs-CRP >1 mg/L + pain VAS ≥7 → LR+ 19.07, post-test 96%; chained with a positive lag-sign cluster in the trauma/age-conditioned prior the wired full-thickness composite exceeds LR+ 20 (see severity trigger). Loss of PASSIVE external rotation = adhesive-capsulitis pivot. Plain radiograph for trauma / OA / calcific / instability bone lesions. Inflammatory/septic panel ONLY if systemic features (JOSPT 2022 Lafrance PMID 35881707)
   inputs: passive_external_rotation_loss, plain_radiograph, inflammatory_markers
   actions: workup.shoulder_pain, workup.tendinopathy, panel.inflammation
   advance: Conditionally-dependent provocative-test cluster scored (NOT product of singles), passive-ROM pivot assessed, radiograph obtained if indicated
6. 6BRANCHING_WORKUP
   T_test threshold — Ultrasound OR MRI ONLY when the result changes management: surgical-candidate or ACUTE TRAUMATIC full-thickness tear, instability/labral lesion (MR-arthrogram), refractory atypical course, or referred-cause confirmation (cervical MRI / ECG / CXR for Pancoast). CONDITIONAL-DEPENDENCE refinement: a subacromial LIDOCAINE block conditions the lag-sign LR — after the block the specificity and LR+ of Jobe / external-rotation lag / drop-arm RISE while sensitivity falls (Bak 2010 PMID 20511030, Level-I), so a lag sign that persists post-block is a stronger rule-IN for a true full-thickness tear (pain-inhibition false-positives removed). US LR for any full-thickness tear is itself conditioned on operator/age (US sens ~0.91 spec ~0.85 in expert hands → LR+ ~6, lower in incidental elderly tears — JOSPT 2022 Lafrance). Capsular-pattern confirmation for adhesive capsulitis; route to msk.fracture-triage.core.v1 if a radiograph shows an occult proximal-humerus/greater-tuberosity fracture, to msk.osteoarthritis.core.v1 for glenohumeral/AC degenerative joint disease as the dominant generator. Imaging restraint otherwise (JOSPT 2022 Lafrance; AAOS 2019; Bak 2010 PMID 20511030)
   inputs: ultrasound_or_mri_shoulder
   actions: workup.tendinopathy
   advance: Imaging done only where it changes management; lag-sign|lidocaine-block conditional applied; phenotype-specific workup complete
7. 7DIFFERENTIAL
   MECE: rotator-cuff tendinopathy vs partial-thickness vs full-thickness tear vs subacromial (impingement) pain vs adhesive capsulitis (PASSIVE ER loss pivot) vs glenohumeral instability vs AC-joint OA vs calcific tendinitis vs referred (cervical radiculopathy, cardiac, diaphragmatic). PIVOTS: (1) capsulitis vs cuff = global PASSIVE ER loss (capsulitis) vs ACTIVE>passive loss (cuff) — pivot interpreted against the diabetes-conditioned prior; (2) shoulder vs neck = provocative shoulder tests negative + pain reproduced by neck/Spurling → route msk.mechanical-neck-pain.core.v1 (carryover: neck-ROM, Spurling, dermatomal/myotomal map); (3) regional vs polyarticular inflammatory = if a hot/swollen shoulder is part of a symmetric small-joint synovitis with morning stiffness >1 h / raised CRP-ESR → route rheum.rheumatoid-arthritis.core.v1 (carryover: joint count, inflammatory markers, RF/anti-CCP intent); (4) mechanical pain vs central sensitisation = if shoulder pain sits within a widespread-pain / non-anatomic-tenderness pattern with normal structural workup → consider co-existent central pain and route msk.fibromyalgia.core.v1 (carryover: widespread-pain index, sleep, somatic-symptom burden); (5) chronic cuff degeneration vs degenerative glenohumeral/AC OA → msk.osteoarthritis.core.v1; (6) load-related cuff tendinopathy as a regional instance of the shared progressive-loading model → msk.tendinopathy.core.v1. Co-existence handled: degenerative cuff tear is frequently INCIDENTAL in the elderly (prior-conditioned — do not over-attribute); capsulitis can co-exist with cuff disease; cervicobrachial pain can co-exist with cuff disease (treat dominant generator, re-screen the other) (UK FROST Rangan 2020 PMID 33010843; JOSPT 2022 Lafrance PMID 35881707; AAOS 2019)
   inputs: passive_external_rotation_loss
   advance: Terminal phenotype assigned with the passive-ROM pivot, co-existence handled, and cross-dossier route selected when a non-cuff generator dominates
8. 8RISK_STRATIFICATION
   Tear size / acuity / activity demand (acute traumatic full-thickness in active patient = surgical-window high-priority); capsular phase (freezing / frozen / thawing); instability recurrence risk (age, dislocation count, contact sport); functional disability and occupational demand; NSAID-comorbidity risk (eGFR/GI/CVD) (JOSPT 2022 Lafrance; AAOS 2019)
   inputs: age, prior_dislocation_count
   actions: calc.ckd_epi_2021
   advance: Phenotype-specific risk tier + surgical-window timing documented
9. 9TREATMENT
   Education + progressive task-oriented exercise/physiotherapy is FIRST-LINE for subacromial pain / cuff tendinopathy / degenerative tears (CSAW Beard Lancet 2018 PMID 29169668 — decompression no clinically important benefit; FIMPACT Paavola BJSM 2021 PMID 33020137 — no benefit vs placebo or exercise at 5 y; Cochrane 2019 Karjalainen PMID 31813166 — cuff repair little/no clinically important benefit over exercise for degenerative tears). NSAID (naproxen / ibuprofen) and a SINGLE transient subacromial/intra-articular corticosteroid injection (methylprednisolone; triamcinolone — rxcui omitted) are short-term ADJUNCTS, not substitutes (Bloom Cochrane 2012 PMID 22895984 — benefit transient, image guidance not required). Adhesive capsulitis: early structured physiotherapy + intra-articular steroid (UK FROST Rangan Lancet 2020 PMID 33010843 — no surgical modality clinically superior); short oral prednisone course debated; diabetic steroid-glycaemia caution. ACUTE traumatic full-thickness tear in an active patient → expedited surgical referral (the time-critical exception). Acetaminophen as a weak adjunct (JOSPT 2022 Lafrance PMID 35881707)
   inputs: ckd_gi_cvd_status, diabetes_or_thyroid
   advance: Exercise-first plan set, adjuncts gated by comorbidity, surgical-referral decision documented
10. 10DISPOSITION
    Almost all outpatient. Expedited surgical referral for acute traumatic full-thickness tear / recurrent instability. ED for septic joint, vascular compromise, acute progressive neuro deficit, or unreduced dislocation (JOSPT 2022 Lafrance; AAOS 2019)
    advance: Level of care + specialty referral set
11. 11MONITORING
    Re-screen red flags at each visit; reassess pain / function and ROM; expect SLOW recovery (weeks–months for cuff/subacromial; 1–3 y natural history for frozen shoulder); NSAID safety review (renal/GI/CVD); enforce the corticosteroid-injection number ceiling; diabetic glucose monitoring after steroid (JOSPT 2022 Lafrance; UK FROST Rangan 2020)
    inputs: ckd_gi_cvd_status
    actions: calc.ckd_epi_2021
    advance: Trajectory on track or non-responder flagged for re-phenotyping / imaging
12. 12FOLLOWUP
    Exercise maintenance, activity / work modification, return-to-work and return-to-sport planning (JOSPT 2022 Lafrance return-to-work module), recurrence and red-flag return precautions; re-evaluate persistent / worsening symptoms for re-phenotyping or delayed imaging / surgical opinion (JOSPT 2022 Lafrance)
    advance: Long-term self-management + return-to-work/sport + return precautions in place