Extremity Set Ups

Extremity stations reward the candidate who can turn a restricted motion into a glide direction in one sentence, then build a set up that is safe, modest and easy for an examiner to follow. Every joint in this chapter is handled with the same logic: screen for fracture, instability and the conditions that mimic a simple joint restriction; apply the convex concave rule; place the joint in a position that allows play; then contact, stabilize and drive along the treatment plane. Get that logic right and the shoulder, elbow, wrist, hip, knee, ankle and foot all become variations on one performance.

Section 1Shoulder and acromioclavicular set ups

The rule that runs every extremity station

Extremity adjustments restore joint play, the small passive accessory glides that a joint must have for its voluntary range to be normal. Joint play cannot be produced by the patient; it is assessed by the doctor with the joint in a relaxed position. When a voluntary motion is restricted, the missing accessory glide is predicted by the shape of the moving joint surface:

• When a convex surface moves on a fixed concave surface, the roll and the glide go in opposite directions. The humeral head, femoral head, proximal carpal row on the radius, and the talus in the mortise are convex.
• When a concave surface moves on a fixed convex surface, the roll and the glide go in the same direction. The tibial plateau on the femur, the ulna on the trochlea, the bases of the phalanges and the radial fovea on the capitulum are concave.

So if the humerus will not abduct (the shaft moves up), the convex head must glide down: the treatment is an inferior glide. If the knee will not extend (the tibia moves forward on the femur), the concave plateau must glide forward: the treatment is an anterior tibial glide. Say the rule aloud on a station; it is how the examiner hears that your line of drive is reasoned and not memorized.

Glenohumeral set ups

Before any shoulder set up, screen for dislocation and instability (a history of the shoulder "coming out," a positive apprehension test), fracture (trauma in an older patient, a fall on the outstretched hand, deformity, bruising), full thickness rotator cuff tear (weakness, drop arm sign), adhesive capsulitis in its painful freezing phase, and referred pain from the heart, lung apex (Pancoast tumor), diaphragm, gallbladder or cervical spine. Left shoulder pain with exertional chest pressure or dyspnea is cardiac until proven otherwise.

Acromioclavicular and sternoclavicular set ups

The acromioclavicular (AC) joint is a small plane joint that is commonly sprained by a fall on the point of the shoulder. Separations are graded: grades I and II (sprain of the AC ligaments, with partial coracoclavicular involvement in grade II) are managed conservatively; grade III and above (complete coracoclavicular rupture with obvious step deformity, or displacement posteriorly, superiorly or inferiorly) need orthopedic evaluation. Any visible step, a piano key sign, or displacement on comparison stress views is a reason to image and refer rather than adjust. After healing, AC restriction is usually found as a superior or posterior distal clavicle.

The sternoclavicular (SC) joint is a saddle joint with a disc. The common finding is an anterior medial clavicle. A posterior SC displacement can compress the trachea, esophagus and great vessels: hoarseness, dysphagia, dyspnea or venous congestion after trauma to the shoulder or chest is an emergency referral. Never apply posterior pressure to a medial clavicle that is already posterior.

Scapulothoracic mobilization (patient side lying, doctor cupping the scapula and gliding it superiorly, inferiorly, medially, laterally and in rotation) is a useful adjunct, especially when the scapula is held by tight upper trapezius, levator scapulae or pectoralis minor.

Section 2Elbow, wrist and hand set ups

Elbow: three joints in one capsule

The elbow contains the humeroulnar joint (a hinge: concave trochlear notch on the convex trochlea), the humeroradial joint (concave radial fovea on the convex capitulum) and the proximal radioulnar joint (convex radial head rim turning in the concave radial notch, held by the annular ligament). Flexion and extension happen mainly at the humeroulnar joint; pronation and supination at the radioulnar joints. A commonly taught arthrokinematic link is that the radial head glides posteriorly (dorsally) with pronation and anteriorly with supination, so a radial head fixed posterior tends to limit supination and one fixed anterior tends to limit pronation.

Screen the elbow for supracondylar fracture in children (a fall on the outstretched hand, swelling, refusal to move; check the radial pulse and the anterior interosseous, median, radial and ulnar nerves), radial head fracture in adults (lateral elbow tenderness, painful pronation and supination, a positive fat pad sign on the lateral radiograph), posterior dislocation, septic olecranon bursitis (warm, red, fever) and ulnar nerve symptoms at the cubital tunnel.

The pulled elbow

Radial head subluxation (pulled or nursemaid's elbow) occurs in children roughly 1 to 4 years old when a sudden pull on the extended, pronated arm draws the radial head partly out of the annular ligament. The child stops using the arm and holds it slightly flexed and pronated, with little swelling. Reduction is by hyperpronation or by supination with flexion, often with a palpable click and rapid return of use. The critical judgment is the mechanism: a pull fits subluxation, but a fall, visible swelling, bruising or point tenderness suggests fracture and calls for radiographs first. If the child does not use the arm normally within a short time after a reduction attempt, refer for imaging.

Wrist and carpals

At the radiocarpal joint the convex proximal carpal row moves on the concave radius and articular disc, so wrist flexion requires a dorsal glide of the carpals and extension requires a palmar glide. Individual carpals are listed by the direction of their displacement, most often dorsal (posterior). The capitate, the keystone of the distal row, and the lunate are the carpals most often addressed.

Screen the wrist carefully. Scaphoid fracture follows a fall on the outstretched hand and causes tenderness in the anatomical snuffbox and over the scaphoid tubercle; initial radiographs may be normal, so the wrist is splinted and reimaged or scanned, because missed scaphoid fractures risk nonunion and avascular necrosis of the proximal pole. Lunate dislocation (usually palmar) can compress the median nerve and is an emergency. Kienböck disease (avascular necrosis of the lunate) causes dorsal central wrist pain. Distal radius fractures (Colles with dorsal displacement, Smith with palmar displacement) must be excluded after a fall. Do not thrust a wrist with rheumatoid arthritis and ligament laxity.

Hand and phalanges

At the metacarpophalangeal and interphalangeal joints the concave base of the distal bone moves on the convex head of the proximal bone, so flexion requires a palmar glide and extension a dorsal glide of the distal bone. The simplest and safest technique is long axis distraction: the doctor grasps the proximal bone with one thumb and index finger, the distal bone with the other, takes up slack along the axis and applies a gentle tug, often with a small cavitation. Dorsal and palmar glides and gentle rotation follow the same grip. The thumb carpometacarpal joint is a saddle joint; distraction and glides in its two planes help arthritic stiffness when applied gently.

Screen the hand for ulnar collateral ligament rupture of the thumb (skier's or gamekeeper's thumb; laxity on valgus stress, possible Stener lesion needing surgery), mallet finger (extensor tendon avulsion, needs continuous splinting), boutonnière deformity (central slip injury), flexor tenosynovitis (the Kanavel signs: fusiform swelling, flexed resting posture, tenderness along the sheath, pain on passive extension; a surgical emergency), and inflammatory arthritis.

Section 3Hip set ups

Screen the hip before you touch it

Hip pain is a common door card because it hides serious conditions behind an ordinary complaint. Before any hip set up, you must be able to say why the hip in front of you is not one of these:

The hip's capsular pattern is loss of internal rotation most, then flexion and abduction, with less loss of extension; early osteoarthritis is often found first as painful, limited internal rotation and a positive FADIR or FABER with groin pain. Femoroacetabular impingement in younger active adults produces groin pain with flexion, adduction and internal rotation.

Long axis distraction

Long axis distraction separates the femoral head from the acetabulum and is the foundation hip technique, useful for capsular stiffness and early degenerative change. The patient lies supine with the hip in its resting position (about 30 degrees of flexion, 30 degrees of abduction and slight external rotation). The doctor stands at the foot of the table and grasps the leg just above the malleoli, or, if the knee is unstable or painful, the distal femur above the knee with the patient's knee flexed over the doctor's shoulder or forearm. The doctor leans back to take up slack, holds for a breath, and then applies a quick, shallow tug along the long axis of the femur. A belt across the patient's pelvis or the patient holding the table edges keeps the trunk from sliding.

Anterior and posterior glides

The convex femoral head glides opposite to the movement of the shaft. Flexion and internal rotation require a posterior glide; extension and external rotation require an anterior glide; abduction requires an inferior glide.

Section 4Knee set ups

Tibiofemoral joint

At the tibiofemoral joint the concave tibial plateau moves on the convex femoral condyles, so the tibia glides in the same direction as the leg moves: extension requires an anterior glide of the tibia and flexion requires a posterior glide. Terminal extension is accompanied by external rotation of the tibia (the screw home mechanism), unlocked by the popliteus at the start of flexion; a knee that lacks the last few degrees of extension may be missing that rotation as well as anterior glide.

Screen the knee before any set up. The Ottawa knee rules call for radiographs after acute injury if the patient is 55 or older, has isolated tenderness of the patella, tenderness at the fibular head, cannot flex to 90 degrees, or cannot bear weight for four steps both immediately and at the examination. A tense effusion within about 2 hours of injury is a hemarthrosis, which suggests an anterior cruciate ligament tear, a fracture or a patellar dislocation. A knee that is locked (cannot extend fully, with a springy block) suggests a displaced bucket handle meniscal tear and needs orthopedic referral, not a thrust. Fever with a hot swollen knee is septic arthritis until proven otherwise. Calf pain and swelling raise concern for deep vein thrombosis, and a ruptured Baker cyst can mimic it.

Ligament tests come first because two of the knee glides are the drawer tests in disguise: never perform an anterior tibial glide on a knee with a torn anterior cruciate ligament, or a posterior glide on a knee with a torn posterior cruciate ligament.

Proximal tibiofibular joint and the fibular head

The proximal tibiofibular joint is a plane synovial joint on the posterolateral tibial condyle. The fibula moves slightly with ankle motion: with ankle dorsiflexion the fibula rises and rotates, and inversion ankle sprains are commonly taught to disturb the fibula at both ends. A posterior fibular head is the most commonly taught listing, often after an inversion sprain or with lateral knee pain in runners; an anterior fibular head is less common.

The common fibular (peroneal) nerve winds around the fibular neck just below the head, where it is superficial and easily compressed. Contacts must sit on the fibular head itself, not on the neck, and the patient should be told to report any tingling into the lateral leg or dorsum of the foot. Foot drop, numbness of the first web space or weakness of ankle dorsiflexion and eversion after a knee injury suggests fibular nerve injury and requires referral.

Patellar mobilization

The patella must glide inferiorly for full knee flexion and superiorly for full extension, and medial and lateral glides and tilts are needed for normal tracking. With the patient supine and the knee fully extended and relaxed (a small roll under the knee if the patient cannot relax), the doctor uses the thumbs and index fingers on the patellar borders or the heel of the hand on the patellar base or apex to apply superior, inferior, medial and lateral glides, held or oscillated. Avoid compressing the patella into the femur in patellofemoral pain, and avoid lateral glides after a patellar dislocation (lateral apprehension test positive). Quadriceps tightness (especially the vastus lateralis and the iliotibial band) and a weak vastus medialis are treated alongside.

Section 5Ankle and foot set ups

Screen with the Ottawa rules

After an acute ankle or midfoot injury, the Ottawa ankle and foot rules decide whether radiographs come before treatment. Ankle films are indicated with pain in the malleolar zone and bone tenderness along the posterior edge or tip of either malleolus (the distal 6 cm), or inability to bear weight for four steps both immediately and at the examination. Foot films are indicated with pain in the midfoot zone and tenderness at the base of the fifth metatarsal or the navicular, or the same weight bearing failure. Beyond the rules, screen for an Achilles tendon rupture (a palpable gap, weak plantarflexion, positive Thompson test), a high ankle (syndesmotic) sprain (pain with squeeze and external rotation tests), a Lisfranc injury (midfoot pain, plantar bruising, widening between the first and second metatarsal bases), stress fracture (point tenderness of a metatarsal shaft in a runner), Charcot neuroarthropathy (a warm, red, swollen foot in a person with diabetic neuropathy, often with little pain), gout at the first metatarsophalangeal joint, deep vein thrombosis and compartment syndrome. Check pulses and sensation in every diabetic foot before you touch it.

Talocrural and subtalar set ups

The convex talus rolls and glides in the concave mortise, so dorsiflexion requires a posterior talar glide and plantarflexion an anterior glide. After an inversion sprain the talus is commonly found anterior with restricted dorsiflexion, and the cuboid and fibula are often involved too. The foundation technique is talocrural long axis distraction (the "ankle tug"): patient supine, the doctor at the foot of the table interlaces the fingers over the dorsal talar neck with the thumbs on the plantar surface, takes the ankle into its resting position, leans back to take up slack and gives a quick, shallow tug along the long axis of the leg.

Cuboid, navicular and metatarsal techniques

Cuboid syndrome (a plantar, often medially rotated cuboid) causes lateral midfoot pain after an inversion sprain or with repetitive loading in dancers and runners; push off is painful and the plantar cuboid is tender. The classic correction is the cuboid whip: the patient lies prone with the knee flexed about 70 to 90 degrees; the doctor's thumbs overlap on the plantar medial aspect of the cuboid and the fingers wrap the dorsum; the doctor whips the foot from slight dorsiflexion into plantarflexion and, at end range, the thumbs deliver a thrust plantar to dorsal. A gentler alternative is a squeeze (sustained plantar to dorsal pressure). Do not perform a whip until fracture of the fifth metatarsal base and a Lisfranc injury have been excluded, and avoid it in an unstable ankle.

A plantar (inferior) navicular is associated with a dropped medial longitudinal arch and medial midfoot pain. The patient lies supine or prone; the doctor's thumb contacts the plantar navicular just behind its tuberosity, the other hand stabilizes the forefoot, and the line of drive is plantar to dorsal (with a slight medial to lateral component). Navicular stress fracture (point tenderness on the dorsal "N spot" in a jumping athlete) must be excluded first.

At the metatarsals, adjacent heads are glided against each other in dorsal and plantar directions (a "shear"), and the forefoot is spread gently. The first metatarsophalangeal joint follows the concave rule for the proximal phalanx: extension (needed for push off) requires a dorsal glide of the phalanx, so hallux limitus is treated with long axis distraction and dorsal glides, never in an acute gout flare. Avoid squeezing the forefoot over a Morton neuroma between the third and fourth heads.

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