12-phase flow (12)

1. 1FRAME
   Frame the encounter across three lanes: (a) decision-rule image-vs-no-image triage, (b) cannot-miss occult / limb-threatening fracture library, (c) fragility-fracture secondary-prevention loop for low-trauma fracture ≥ 50 (Stiell JAMA 1993 PMID 8433468; BHOF 2022 PMID 35478046)
   inputs: age, mechanism_and_energy
   advance: Scope (decision-rule vs cannot-miss vs fragility lane) framed
2. 2ENTRY
   Acute extremity trauma / deformity / dislocation / open wound; OR low-trauma fall ≥ 50 (sentinel); OR atraumatic bone pain; OR recurrent fragility fracture re-entry (ACEP extremity policy)
   inputs: mechanism_and_energy
   advance: Recognised entry trigger present
3. 3CONTEXT
   Mechanism + energy, age, time since injury (>48 h degrades Ottawa applicability), intoxication / distracting injury / neuro deficit (rule-validity gates), prior fragility fracture, glucocorticoid use, malignancy/myeloma history, anticoagulation, bone-health risk factors (Stiell JAMA 1993 PMID 8433468; BHOF 2022 PMID 35478046)
   inputs: age, mechanism_and_energy, time_since_injury, intoxication_or_distracting_injury, glucocorticoid_or_bone_risk_factors
   advance: Energy, applicability gates, and bone-health context captured
4. 4RED_FLAGS
   Cannot-miss screen: open fracture (time-critical antibiotics + tetanus + washout); neurovascular compromise (absent pulses / abnormal cap-refill / sensorimotor deficit / ABI < 0.9 → emergent reduction + vascular/ortho); acute compartment syndrome (6 P’s; pain out of proportion + pain on passive stretch; ΔP = diastolic − compartment pressure < 30 mmHg → emergent fasciotomy, McQueen PMID 8898137); joint dislocation (reduce promptly, neurovascular before+after); occult elderly hip fracture (negative plain film does NOT exclude); pathologic fracture (malignancy features); septic arthritis mimicking
   inputs: distal_neurovascular_status, open_wound_over_fracture, pain_out_of_proportion
   actions: workup.fracture_triage, panel.cbc
   advance: Limb-threatening / cannot-miss patterns screened and escalated if present
5. 5INITIAL_WORKUP
   Apply Ottawa Ankle/Foot rule → image vs no-image (pooled sens ~97.6%, LR− 0.08 (0.03–0.18), radiograph reduction 30–40%; Bachmann BMJ 2003 PMID 12595378) AND Ottawa Knee rule (pooled sens 0.99 (0.97–1.00), LR− 0.07 (0.02–0.24), LR+ 1.86 (1.72–2.01), DOR 25.1; Sims Eur Radiol 2020 PMID 32222797; corroborated sens 0.98, LR− 0.12 (0.05–0.26), LR+ 1.56 across 18 studies / 6702 pts, Kazemi Arch Acad Emerg Med 2023 PMID 37215241). §5.5.2 CONDITIONAL DEPENDENCE: each rule’s operating characteristics hold ONLY inside its derivation population and an examinable patient — LR− is uninterpretable (reverts toward 1) if intoxicated / distracting injury / diminished sensation / age outside band / >48 h delay; the load-bearing wired LR is the COMPOSITE decision-rule-positive + inability-to-weight-bear + focal bony tenderness path (occult/clinically-important fracture LR+ ≥ 12 in the rule-applicable population — strongest wired LR, Stiell JAMA 1994/1996; Sims PMID 32222797 DOR 25.1). Targeted plain radiographs ≥2 views (joint above and below) if rule positive / inapplicable / high pretest; full distal neurovascular exam; in low-trauma fracture ≥ 50 → CBC + metabolic + 25-OH vitamin D + FRAX (BHOF 2022 PMID 35478046; Kanis PMID 18292978)
   inputs: ability_to_weight_bear, bony_tenderness_site
   actions: calc.ottawa_ankle_rule, calc.ottawa_knee_rule, workup.fracture_triage, panel.cbc, panel.metabolic
   advance: Decision rule applied (or documented inapplicable → image not rule) + radiograph obtained when indicated + bone-health screen sent if low-trauma ≥ 50
6. 6BRANCHING_WORKUP
   Negative XR but high occult pretest → advanced imaging. §5.5.2 OCCULT-SCAPHOID conditional-dependence composite: ED pretest ~25% (Carpenter Acad Emerg Med 2014 PMID 24673666); ABSENCE of anatomical-snuffbox tenderness LR− 0.15 (rule-out anchor, Carpenter PMID 24673666); single findings weak (snuffbox sens 0.93 (0.87–0.97), axial-loading spec 0.66 (0.41–0.85), Huynh/Chung Plast Reconstr Surg 2021 PMID 33620933) — but the conditional-dependent COMPOSITE of snuffbox + scaphoid-tubercle + axial-load tenderness lifts post-test to ~60% at 20% prevalence (Huynh/Chung PMID 33620933; combining tests raises specificity/post-test while preserving sensitivity, Mallee J Hand Surg Am 2014 PMID 25091335) → scaphoid MRI (superior to CT/US/bone-scan, Carpenter PMID 24673666) or thumb-spica + re-image 10–14 d. Elderly inability-to-weight-bear + groin pain → hip MRI within 24–72 h (most sensitive) or CT. Suspected pathologic fracture → CT/MRI + primary workup. Low-trauma ≥ 50 / recurrent → DXA + secondary-osteoporosis labs + FRAX; FRAX|BMD conditional dependency — prior-fracture subsequent-risk HR 1.88 (any clinical fx) / 1.82 (hip), BMD explains only 14–33% of that risk so do NOT withhold treatment of the sentinel fracture pending DXA (Kanis Osteoporos Int 2023 PMID 37566158; FRAX±BMD adjustment framework McCloskey/Kanis 2012 PMID 22820516; TBS-FRAX works with or without femoral-neck BMD, Leslie J Clin Densitom 2023 PMID 37137791) (BHOF 2022 PMID 35478046)
   inputs: vitamin_d_calcium
   actions: workup.osteoporosis, calc.frax, panel.vitamin_d, panel.metabolic
   advance: Occult fracture excluded/confirmed via conditional-dependent composite; fragility-fracture workup initiated
7. 7DIFFERENTIAL
   MECE pivots: fracture vs ligamentous sprain vs dislocation/subluxation vs septic arthritis vs soft-tissue contusion vs pathologic fracture vs stress/insufficiency fracture vs CRPS (late). Co-existence allowed: fracture-dislocation, fracture + neurovascular injury, pathologic + low-energy (Stiell JAMA 1994/1996; ACEP extremity policy). LOOK-ALIKE / cross-dossier routing by engine_id when fracture excluded: Ottawa-Knee-negative low-pretest knee → msk.knee-pain.core.v1 (internal derangement / OA / extensor mechanism); shoulder trauma, no fracture / non-acute → msk.shoulder-pain.core.v1 (rotator-cuff / instability); axial / thoracolumbar focal tenderness or height loss without acute high-energy fracture → msk.low-back-pain.core.v1 + endo.osteoporosis.core.v1 (occult vertebral fragility fracture); cervical-trauma but Canadian C-Spine Rule low-risk and cleared → msk.mechanical-neck-pain.core.v1 (Stiell JAMA 2001 PMID 11597285). Carryover: mechanism, energy, decision-rule output, exam findings, imaging done
   inputs: mechanism_and_energy
   advance: Terminal diagnosis assigned or occult fracture provisionally treated, or routed to the matching regional engine with carryover
8. 8RISK_STRATIFICATION
   Decision-rule output (image / no image; pooled LR− 0.08 (0.03–0.18) negative ankle/foot Bachmann PMID 12595378, LR− 0.07 (0.02–0.24) negative knee Sims PMID 32222797). §5.5.2 FRAGILITY imminent-risk tier is CONDITIONAL on (a) fracture RECENCY — subsequent-fracture hazard is time-dependent and HIGHEST in the first 1–2 years after the sentinel fracture then attenuates (the prior-fracture risk ratio decreases significantly with time since baseline, Kanis Osteoporos Int 2023 PMID 37566158; BHOF 2022 PMID 35478046), and (b) fracture SITE — vertebral fracture confers ~5-fold further vertebral and 2–3× other-site risk vs ~1.8× for a generic prior fracture (BHOF 2022 PMID 35478046; Kanis PMID 37566158); and (c) FRAX|BMD — FRAX major/hip vs NOGG intervention threshold computed WITH or WITHOUT femoral-neck BMD (TBS adjustment valid either way, Leslie J Clin Densitom 2023 PMID 37137791; McCloskey/Kanis 2012 PMID 22820516) since BMD explains only 14–33% of prior-fracture risk (Kanis PMID 37566158). Compartment-syndrome risk (tibial shaft, forearm; ΔP < 30 mmHg McQueen PMID 8898137); occult-fracture pretest; weight-bearing status. ROUTING: vertebral-fragility presentation → carryover to msk.low-back-pain.core.v1 + endo.osteoporosis.core.v1; any fragility tier → endo.osteoporosis.core.v1 with FRAX/recency/site/eGFR/glucocorticoid payload
   inputs: ability_to_weight_bear
   actions: calc.frax, calc.ottawa_ankle_rule, calc.ottawa_knee_rule
   advance: Imaging tier + recency-and-site-conditioned fragility imminent-risk tier + compartment risk documented
9. 9TREATMENT
   Reduction / splint / immobilisation by stability. Multimodal opioid-sparing analgesia: scheduled acetaminophen (rxcui 161) + NSAID (ibuprofen 5640 / naproxen 7258) if no CKD/PUD/CVD/bleeding/healing contraindication; regional fascia-iliaca compartment block for geriatric hip fracture (reduces opioid + delirium; RCT/meta PMID 38012873/36991402); opioid rescue geriatric-cautious (STOPP/START). VTE-prophylaxis decision for lower-limb immobilisation (pharmacologic for higher-risk lower-limb cast / hip fracture; not routine for minor immobilisation). Open fracture: tetanus + early IV antibiotics (cefazolin ± gram-negative by Gustilo grade) + washout within hours + urgent ortho. FRAGILITY-FRACTURE LOOP: vitamin D / calcium repletion + start anti-resorptive (oral bisphosphonate first-line; zoledronate / denosumab if oral unsuitable; anabolic if very-high-risk) + route to endo.osteoporosis.core.v1 via fracture-liaison service (BHOF 2022 PMID 35478046; NOGG 2024)
   inputs: renal_function, anticoagulation
   actions: workup.osteoporosis
   advance: Immobilised/reduced + analgesia + VTE decision made + fragility loop initiated/routed
10. 10DISPOSITION
    Ortho referral / OR criteria (displaced / angulated / intra-articular / unstable / open / neurovascular / hip fracture); explicit weight-bearing status; admit (hip fracture, open fracture, neurovascular, compartment, uncontrolled pain) vs discharge with splint + ortho follow-up + return precautions; fracture-liaison-service referral for fragility fracture (BHOF 2022 PMID 35478046; ACEP extremity policy)
    advance: Level of care + weight-bearing + ortho/FLS referrals set
11. 11MONITORING
    Serial neurovascular checks after splinting/reduction; repeat XR for displacement at follow-up; scaphoid re-image at 10–14 d if initially occult; compartment-syndrome serial exam in at-risk; healing surveillance; bone-health follow-up labs (BHOF 2022 PMID 35478046)
    inputs: distal_neurovascular_status
    actions: panel.metabolic
    advance: No neurovascular deterioration; healing on track; bone-health monitoring scheduled
12. 12FOLLOWUP
    Orthopaedic follow-up; cast/splint care + physiotherapy; fragility-fracture secondary prevention long-term — DXA, anti-resorptive adherence, falls assessment, vitamin D/calcium — routed BIDIRECTIONALLY to endo.osteoporosis.core.v1 (this engine sends FRAX inputs + recency + site + eGFR + glucocorticoid + vitamin D; the sibling owns the anti-resorptive/anabolic ladder and routes back any on-treatment fracture as a fresh sentinel re-entry). Persistent regional pain after bony healing routes to the matching engine: knee → msk.knee-pain.core.v1, shoulder → msk.shoulder-pain.core.v1, back/vertebral → msk.low-back-pain.core.v1, neck → msk.mechanical-neck-pain.core.v1, with the fracture history as carryover. Return precautions (increasing pain, numbness, colour change, fever) (BHOF 2022 PMID 35478046; Kanis PMID 37566158; NICE NG38)
    actions: workup.osteoporosis, calc.frax
    advance: Ortho + FLS / osteoporosis follow-up booked; regional-pain handoff done if indicated; education + return precautions given