The curriculum · seventeen modules

Reading the joint you actually have

Every module here exists because a field once aimed at an average and the average was not the patient. The programme teaches one habit — measure how the joint behaves under load, find what the correction should answer to, and let that drive the plan — across eleven joints that learned it separately and never compared notes.

The eleven instruments on this site are the practical. Each module names the one you work a case through, so the teaching is never only reading.

17 modules · 4 parts11 instruments as practicalsSelf-pacedNo accreditation, no CME

Start from the case, not the syllabus

What are you operating on this week?

Seventeen modules is a syllabus. Pick the joint in front of you and the programme gives you the six that matter for it, in order — the other eleven stay exactly where they are.

What this is, in one paragraph

Read this before anything else on the page.

This is a self-directed curriculum written by an MD with deep clinical training who is not a practising surgeon and not a licensed physician. It carries no accreditation and awards no credential. Its instruments have never been used to plan an operation on a living person, and a substantial number of the constants inside them were invented for the model rather than taken from a paper — Module 16 exists to list exactly which.

What it is good for: learning to ask a joint a better question than a fixed target asks. What it is not good for is deciding what to do to a patient in front of you.

What this is not

Not accredited and not CME. No body has reviewed it and nothing here counts toward anything.
Not certification. The competency lines below are self-assessment prompts, not a qualification anyone should accept as evidence of skill.
Not clinical decision support and not a medical device. No output should reach a patient decision.
Not a rehabilitation or exercise programme. Module 17 covers what determines outcomes between visits; it does not prescribe.
The marks are not a record. Ticking a module stores a number in your own browser and nothing else. No account, no server, no tracking, and it certifies nothing — clear it any time and it is gone.
Not a substitute for the judgement of the surgeon responsible for the patient.

The syllabus

Four parts. Part II is eleven joints grouped by the question they answer, not by anatomy — that grouping is itself the finding.

PART IThe methodThree modules · no joint yet

The envelope

How a joint behaves under load across its arc, rather than how it looks on a static film. The difference between a measurement taken once, lying down, and a measurement taken in the positions the joint actually works in.

You can do this when you can state, for any joint, what would have to be loaded and in which positions for the measurement to mean anything.

The fixed reference

Every correction answers to something. The whole programme turns on choosing that something well: constitutional alignment in the knee, pelvic incidence in the lumbar spine, T1 slope in the neck, the premorbid glenoid in the shoulder. Each replaced a population average that had been treated as a target.

You can do this when you can name the fixed reference for a joint and say what happens to the plan if you pick the wrong one.

Position first, geometry on the residual

Move the components before you change their shape. What position cannot reach is the residual, and the residual — not the whole deformity — is what an implant or an osteotomy has to supply.

You can do this when you can separate, out loud, the part of a correction that positioning will handle from the part that will not.

PART II · ACoupled jointsCoupledAsk what the neighbour is doing

Hip — the pelvis that will or will not move

Spinopelvic mobility read supine, standing and seated. The output is not an angle to aim at but the width of the window you have. A 1A pelvis leaves about 14.5°; a 2B leaves about 2.5°. Immobility narrows the window — deformity does not.

You can do this when you can look at three films and say how much room this particular pelvis leaves you.

Practical: the hip instrument

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 does not know the hip is asking it too. The finding worth the module is that the same deformity burden and the same residual can demand a different operation.

You can do this when you can explain why two identical-looking ankles get different operations.

Corrected mid-build, and taught as a correction. Flexibility was first modelled as free self-correction. It is not. A flexible hindfoot is correctable, and correcting it is the osteotomy — flexibility decides osteotomy-versus-fusion, it does not shrink the burden.

Practical: the ankle instrument

Thumb — the joint above the one that failed

As the thumb base collapses into adduction the MCP hyperextends to keep the web open. Rebuild the base alone and the reconstruction inherits that compensation. Past about 30° the literature treats it as its own decision.

You can do this when you examine a thumb base and look at the joint above it without being told to.

Structural, not kinematic. There is no second position here — the hyperextension is measured once. The 30° point is published; the 20° watch level is this programme's own convention.

Practical: the thumb instrument

Elbow — the operation that fails at the wrist

The forearm is a ring: proximal joint, interosseous membrane, distal joint. The radial head is a secondary stabiliser — expendable only while the coronoid and the medial ligament are intact and the membrane holds. Excise it with an incompetent membrane and the radius migrates; the failure presents months later as ulnar-sided wrist pain, often to a different surgeon.

You can do this when you can say what else must be true before calling any structure expendable.

The instrument reports a disagreement rather than resolving it. The pull-test threshold is >3 mm conventionally and >2 mm by the RAIL criterion. You are taught the gap, not a number.

Practical: the elbow instrument

Shoulder girdle — the ratio that fits no segment

Scapulohumeral rhythm is taught as 2:1. The scapula supplies about 2.5% of the first 30° of elevation and about 52.7% of the arc from 90 to 120; in the series those figures come from, the ratio between 30° and 90° ran from 1.64:1 to 3.76:1 and never once equalled 2:1. This is Module 2's error in miniature, found independently.

You can do this when you can explain why a whole-arc average is the wrong thing to hold a segment to.

Weak signals stay weak. Visible dyskinesis is reported in 68 to 100 per cent of injured shoulders, so on its own it discriminates almost nothing.

Practical: the girdle instrument

Cervical spine — the neighbour you are about to make

T1 slope behaves as the cervical pelvic incidence. This is the only joint in the programme where the adjacent segment is an output of the operation with a published rate — about 2.9% per year, 25.6% at ten years — rather than an input you measure beforehand. Identical films at 45 and at 75 project roughly 76% against 24% cumulative exposure: the target does not move, the exposure does.

You can do this when you can tell the difference between a neighbour you inherited and one you are about to manufacture.

Two warnings that travel with the number. Past ten years it is extrapolation. And whether fusion causes adjacent-segment disease or merely reveals natural history is genuinely contested.

Practical: the cervical instrument

PART II · BAttrition jointsAttritionAsk what is left to build on

Glenoid — the correction budget

How far the glenoid has travelled from its premorbid position, 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.

You can do this when you state the budget before choosing the implant, not after.

The soft-tissue gate sits above the geometry. If the envelope will not tolerate the correction, the arithmetic never runs. Learn the order.

Practical: the glenoid instrument

Wrist — the joint that refuted the rule

Built expecting an envelope; found a gate. No neighbour compensates, there is no second position, and the midcarpal joint is resected rather than recruited. What decides the operation is which articular surfaces survived — a proximal row carpectomy makes the capitate articulate with the lunate fossa, so both must be intact, and stage III degeneration excludes the operation rather than making it harder.

You can do this when you can recognise a joint the programme's central question does not fit, and stop asking it.

Practical: the wrist instrument

PART II · COwn-reference jointsOwn referenceAsk how far it has drifted from itself

Knee — compartment opening drives geometry, not just position

The origin instance. Compartment opening measured under load across the flexion arc, functional-alignment-first, with the soft-tissue envelope read per structure. Valgus and varus fail differently: laxity appearing after the bone cuts is not the same problem as posterior osteophytes producing a fixed flexion contracture.

You can do this when you can say which knees will be hard to balance, and why, before the skin is open.

Stiffness reads the tighter compartment, never an average. Averaging hid a tight medial beside a lax lateral until that was corrected. Conformity slopes and step gain are invented constants.

Practical: the knee instrument · the envelope studio

Foot — supply against the demand of a gait cycle

First MTP dorsiflexion available under load against roughly the 55° walking asks for. 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.

You can do this when you test above and below the joint that hurts.

The weakest module in the programme, and it is taught that way. Weight-bearing passive hallux dorsiflexion in standing has been reported not related to hallux dorsiflexion during walking. The second position this instrument rests on is contested in a way the hip's seated film is not.

Practical: the foot instrument

Lumbar spine — the same films, read the other way

The hip asks will this pelvis move? The spine asks how much of that motion am I about to remove? Two patients with identical radiographs: at 78 the age-adjusted target demands about 26.3° of correction, at 34 about 53.5°. A universal neutral target demands 43° of both — undershooting the younger by about 10° and overshooting the older by about 17°.

You can do this when you can explain why one ideal number is wrong in both directions but dangerous in only one.

The loudest limit in the programme. The age-adjusted values used are approximate brackets showing the shape, not the primary regression — take that from the source. Reported correlations with junctional angle were small. It models a principle, not a plan.

Practical: the lumbar instrument

PART IIIWhat travels between jointsThe structures no single field states

The adjacent segment, and displaced failure

Where the coupled/attrition distinction comes from, and why it is a property of the question rather than of the joint — the same shoulder is an attrition problem at the glenoid surface and a coupled problem at the girdle. Then the third pattern: the elbow and the cervical spine share a failure that lands at a joint nobody operated on.

You can do this when you can sort a new joint into a family by the question being asked of it.

Anchored, invented, and knowing which is which

The module that makes the rest usable. Anchored: the Lewinnek failure rate, the hip-spine classification, Walch types, the Coleman block, Jack's and Silfverskiöld's tests, the 30° MCP point, age-adjusted alignment, the pull-test thresholds, carpectomy staging, scapular share by arc, the adjacent-segment rate. Invented here: conformity slopes, step gain, cup window widths, the ankle's 12° capacity, cheilectomy gains, the 20° MCP watch level, the spine's brackets, and the assumptions of additivity and linearity throughout.

You can do this when you can be handed any number on this site and say which list it belongs to.

What happens between the visits

A measurement-led plan still has to survive the months around it, and a substantial share of what determines a musculoskeletal result happens where nobody is watching. This module covers what the evidence supports about that interval and — just as importantly — where it stops.

The clearest signal is about delay. In a cohort of 67,245 people with knee osteoarthritis, the adjusted risk of opioid use rose in graded fashion with how long physical therapy was delayed, from about 1.25 to about 2.50 across the delay bands, while receiving physical therapy was associated with a lower risk, around 0.77.

Read that carefully, because it is easy to overstate. The relationship is graded, not exponential — do not describe it as exponential. It is an association from observational data and does not establish that delay causes opioid use. And nothing in it tells you what to prescribe to an individual: this module teaches you to notice the interval, not to fill it.

You can do this when you can state what is known about the interval around an operation without inflating it into a protocol.

Patient-facing tracking is a different product with different obligations — it is not built here.

The order it is meant to be taken in

Part I is not optional. Everything after it assumes those three habits.

Stage	Modules	What changes for you
Foundation	01–03	You stop asking what a joint looks like and start asking what it does under load, and what the correction answers to.
One family	Any one of II·A, II·B, II·C	You learn a question well enough to notice when it stops working.
Across families	The other two	The contrast is the teaching. Take the wrist after the hip, not before it.
The structures	15–17	You can place a joint you have never seen, and you know which of your numbers you made up.

There is no examination, no cohort and no schedule. Each instrument keeps its own record of what you rated, and none of it is scored or ranked.

Where this came from

The curriculum is downstream of an argument: three orthopaedic subspecialties independently discovered that their universal anatomical reference was the wrong target, each replaced it with a patient-specific one, and none of them cited the others. The contribution is naming the shared error, not any of the individual fixes.

One module in this syllabus exists because the argument was tested and lost half its claim — the wrist refuted the rule the others were built on, and it is taught in that position rather than quietly dropped.

The programme, all eleven instruments on one page →
The full thesis →