Same six questions asked of every joint, so that they read against each other rather than as eleven separate essays. Each is a working tool, not a diagram.
The colour on the left edge is not decoration — it is the family the joint turned out to belong to, a result explained in § 3.
01
Own reference
Knee
Compartment opening under load, measured across the flexion arc, driving component geometry rather than only component position. The origin instance: functional-alignment-first, with the soft-tissue envelope read per structure and a pre-op clinic rating that predicts the tier before anyone opens anything.
Valgus and varus fail differently and the geometry should answer differently — laxity after the bone cuts is not the same problem as posterior osteophytes producing a fixed flexion contracture.
Honest limit. Conformity slopes, step gain, patellar-track gains and the rating-to-envelope lookup are hypotheses with no clinical validation. Stiffness is read from the tighter compartment, never an average.
Signature — The envelope
Opening under load across the arc — the measurement the implant is cut to, not a target it is aimed at.
Open instrument →
02
Coupled
Hip
Spinopelvic mobility: functional pelvic tilt read supine, standing and seated. The instrument returns not a target angle but the width of the window in which a cup is safe for this particular pelvis.
The finding that matters clinically: immobility narrows the window, deformity does not. A stiff spine — not a deformed one — removes your margin. A 1A pelvis leaves 14.5° to work in; a 2B leaves 2.5°.
The instrument's own arithmetic. Cup window widths are computed here rather than taken from a published table — a way of thinking about margin, not a number to plan from.
Signature — 14.5° → 2.5°
Width of the feasible cup window, 1A pelvis versus 2B. The number is the room you have, not the angle you want.
Open instrument →
03
Attrition
Shoulder · glenoid
How far the glenoid has travelled from its premorbid position, set against how far a reamer may safely go. What will not fit inside that budget is the residual, and the residual is what the construct has to supply — augment, graft, or a different operation.
The soft-tissue gate sits above the geometry, not beside it: if the envelope will not tolerate the correction, the arithmetic never runs.
No mandate reaches here. Neither TEAM nor ASM includes the shoulder. The page says so rather than implying a payment clock it does not have.
Signature — Correction budget
Degrees needed against degrees safely reamable. The gap is what the implant must carry.
Open instrument →
04
Coupled
Ankle
The hip one segment down. The subtalar joint is the adjacent segment and the Coleman block is the seated film — the same two-position question, asked in a vocabulary that has no idea the hip is asking it too.
The result worth the build: the same deformity burden and the same residual can demand a different operation, depending entirely on what the hindfoot is willing to give back.
A modelling error, corrected mid-build. Flexibility was first credited as free self-correction. Wrong: a flexible hindfoot is correctable, and correcting it is the osteotomy. Flexibility decides osteotomy-versus-fusion; it does not shrink the burden.
Signature — What the hindfoot gives back
Compensation available below the ankle, tested past a 5° physiologic allowance.
Open instrument →
05
Own reference
Foot · hallux
First MTP dorsiflexion available under load against roughly the 55° a gait cycle demands. Two nested two-position tests: Jack's test below for the windlass, Silfverskiöld above — because the calf loads the forefoot and the toe is downstream of it. Mid-range pain overrides the arithmetic entirely.
The weakest instrument in the programme, and its page says so first. Weight-bearing passive hallux dorsiflexion in standing has been reported not related to hallux dorsiflexion during walking.
Signature — Arc available vs 55° demanded
45–60° walking, ~65° running. Supply against demand, with pain as an overriding gate.
Open instrument →
06
Coupled
Hand · thumb
The thumb CMC joint, and what the MCP is doing about it. As the base collapses into adduction the MCP hyperextends to keep the web open. Rebuild the base alone and the reconstruction inherits that compensation. The gate is clinical — failed non-operative management — not radiographic.
Structural, not kinematic. There is no second position, the hyperextension is measured once. The 30° decision point is published; the 20° watch level is this tool's own convention, marked as invented.
Signature — MCP compensation
Hyperextension the adjacent joint has taken on. 30° published; 20° is ours.
Open instrument →
07
Own reference
Lumbar spine
The same spinopelvic films as the hip, read in the opposite direction. The hip asks will this pelvis move? The spine asks how much of that motion am I about to remove? A stiff spine is the hip's hazard and this operation's product.
Two identical radiographs: at 78 the age-adjusted target demands 26.3° of correction. At 34 it demands 53.5°. A universal 43° target undershoots the young man by 10.5° and overshoots the elderly woman by 16.7°.
The loudest safety framing in the programme, deliberately. The age brackets are approximate, showing the shape, not the primary regression. Reported correlation with junctional angle was small (r ≈ 0.32): direction supported, precision not.
Signature — 26.3° vs 53.5°
Correction demanded of identical films at 78 and at 34. A 27° swing on age alone.
Open instrument →
08
Coupled — confirms hardest
Elbow · forearm
The forearm is a ring: proximal joint, interosseous membrane, distal joint. The radial head is a secondary valgus stabiliser — expendable only while the coronoid and MCL are intact and the membrane holds.
Excise it with an incompetent membrane and the radius migrates proximally. The failure presents as ulnar-sided wrist pain, months later, at a joint nobody operated on — often to a different surgeon.
Reports the disagreement rather than resolving it. The radius pull test threshold is >3 mm conventionally and >2 mm by the RAIL criterion.
Signature — >3 mm / >2 mm
The two published pull-test thresholds, reported as a gap. Expendability is conditional, never a property of the part.
Open instrument →
09
Attrition — refutes
Wrist · carpus
Built expecting an envelope. Found a gate. No neighbour compensates, there is no second position, and the midcarpal joint is resected rather than recruited.
A proximal row carpectomy makes the capitate articulate with the lunate fossa, so both must be intact — stage III degeneration of the proximal capitate excludes the operation rather than making it harder.
A classifier with a gate, not a calculator — and that is the finding. This joint refuted the programme's own rule, which is why it is here at full length rather than quietly dropped.
Signature — What survives
Capitate head and lunate fossa, intact or not. A gate, not a budget.
Open instrument →
10
Coupled
Shoulder girdle
The scapulothoracic share of elevation — judged against the share expected for that segment of the arc, not against one taught ratio.
Scapulohumeral rhythm is taught as 2:1. In the cited series, no increment of the arc equalled it. The scapula supplies about 2.5% of the first 30° and about 52.7% of the arc from 90° to 120°.
Weak signals stay weak. Visible dyskinesis reaches tier B and never tier C on its own — reported in 68–100% of injured shoulders, so it discriminates almost nothing alone.
Signature — 2.5% → 52.7%
Scapular share of the first 30° versus the 90–120° segment. The taught ratio fits no segment of the arc.
Open instrument →
11
Coupled — displaced failure
Cervical spine
T1 slope behaves as the cervical pelvic incidence, correlating at about r = 0.89 with C0–C7 lordosis. The instrument reads the T1S−CL mismatch and the C2–C7 sagittal axis against a 40 mm threshold.
Symptomatic adjacent-segment disease runs at 2.9% per year and 25.6% at ten years — the model reproduces that figure to within a tenth of a point, the only external calibration in the programme.
Two warnings ride on the output. Past ten years it is extrapolation. Whether fusion causes adjacent-segment disease or merely reveals natural history is genuinely contested.
Signature — 76% vs 24%
Projected adjacent-segment exposure from identical films at 45 and at 75. The neighbour you are about to manufacture.
Open instrument →
12
Not built
The instrument that was never built
Every one of the eleven above depends on a joint being loaded — under body weight, under an examiner's hand, under a block. Nothing in orthopaedics standardises that force. "Stress the joint" means whatever the examiner's grip means that afternoon.
A calibrated stress applicator with a load indicator would put a number under all eleven instruments at once. It is the highest-value missing piece in the programme.
Listed because it is absent. A programme that only shows what it built is advertising, not a record.
Status — —
The measurement every other instrument silently assumes somebody made consistently.