Orthopedic Examination of the Extremities and Musculoskeletal Diagnosis

Most patients with a sore shoulder, a numb hand, a twisted knee or a painful heel can be diagnosed with a careful history, range of motion and the right three or four orthopedic tests. The board rewards the same skill: knowing how each test is done, what a positive looks like and which structure it implicates. This chapter works joint by joint through the extremities, then turns to the patterns that separate sprain from fracture, osteoarthritis from inflammatory arthritis, and a trigger point from fibromyalgia.

Section 1The shoulder

Functional anatomy that drives the tests

The shoulder complex has four articulations: glenohumeral (GH), acromioclavicular (AC), sternoclavicular (SC) and scapulothoracic. The shallow glenoid, deepened by the labrum, relies on the rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) to hold the head centered while the deltoid elevates. The supraspinatus tendon and subacromial bursa pass beneath the coracoacromial arch with every elevation, which is why impingement is the commonest cause of shoulder pain.

Normal active motion is about flexion 180°, extension 50 to 60°, abduction 180°, internal rotation 70 to 90° and external rotation 90°. Scapulohumeral rhythm is about 2 to 1 (120° GH and 60° scapular in full abduction), and the humerus must externally rotate to clear the greater tuberosity overhead.

Always compare active with passive range and add resisted isometric testing. Painful active motion with full painless passive motion and painful resisted movement points to a contractile lesion (muscle or tendon). Loss of both active and passive motion in the capsular pattern (for the GH joint, external rotation most limited, then abduction, then internal rotation) points to the capsule, classically adhesive capsulitis or advanced glenohumeral arthritis. Weakness with full passive range suggests a tear or a nerve lesion.

Impingement

Subacromial impingement is compression of the supraspinatus tendon, the long head of biceps and the subacromial bursa beneath the coracoacromial arch. Contributors include a hooked (type III) acromion, AC osteophytes, weak scapular stabilizers and thoracic kyphosis. Neer described three stages: stage I edema and hemorrhage (typically under age 25, reversible), stage II fibrosis and tendinitis (25 to 40) and stage III bone spurs and tendon rupture (over 40).

Rotator cuff tests

Each cuff muscle has a test that isolates it. The supraspinatus (suprascapular nerve, C5 and C6) initiates abduction and is the tendon torn most often, usually near its insertion on the greater tuberosity in the hypovascular critical zone. Infraspinatus (suprascapular nerve) and teres minor (axillary nerve) externally rotate. Subscapularis (upper and lower subscapular nerves) internally rotates. Calcific tendinitis also favors the supraspinatus.

Instability, biceps and labrum

About 95 percent of GH dislocations are anterior (abduction, external rotation and extension); the shoulder looks squared off and the axillary nerve is most often injured (check the lateral deltoid skin). A Hill Sachs lesion is a posterolateral humeral head impaction fracture and a Bankart lesion an anteroinferior labral avulsion. Posterior dislocation follows seizure or electrocution, with the arm locked in internal rotation and a lightbulb sign on AP.

The AC and SC joints

The AC joint is injured by a fall onto the point of the shoulder with the arm adducted. Tenderness sits directly over the joint, and the cross body adduction test (horizontal adduction of the 90° flexed arm across the chest) compresses it and reproduces pain. The AC shear test squeezes the clavicle and spine of the scapula together. The Rockwood classification grades separations:

The SC joint usually dislocates anteriorly (a visible bump, benign), but a posterior SC dislocation can compress the trachea, esophagus and great vessels: dyspnea, dysphagia or venous congestion of the arm is an emergency.

Adhesive capsulitis

Adhesive capsulitis (frozen shoulder) is fibrosis and contracture of the GH capsule, typically at age 40 to 60, more in women, and strongly associated with diabetes (often bilateral and stubborn), thyroid disease, immobilization and stroke. It passes through a painful freezing phase (to about 9 months), a frozen phase (about 4 to 12 months, stiffness more than pain) and a thawing phase (up to about 2 years). The hallmark is equal loss of active and passive motion in the capsular pattern, external rotation worst, with a firm end feel. Films are normal; arthrography shows a small capsule.

Section 2The elbow, wrist and hand

The elbow

The elbow is three joints in one capsule: the humeroulnar (hinge), the humeroradial and the proximal radioulnar (pivot). Normal motion is about 0° extension to 140 to 150° flexion and 80 to 90° each of supination and pronation. The carrying angle, the valgus angle between arm and forearm in full extension, is about 5 to 15° and greater in women. A cubitus varus (gunstock) deformity is the classic late result of a malunited supracondylar fracture. The capsular pattern is flexion more limited than extension.

The lateral epicondyle is the common extensor origin (ECRB is the key tendon in lateral epicondylopathy) and the medial epicondyle the common flexor and pronator origin. The ulnar collateral ligament resists valgus and fails in throwers; the radial collateral complex resists varus. The ulnar nerve runs in the cubital tunnel behind the medial epicondyle.

Lateral epicondylopathy (tennis elbow) is degenerative tendinosis of the ECRB origin from repetitive gripping and wrist extension, peaking at 35 to 55 years; most patients do not play tennis. It must be distinguished from radial tunnel syndrome (tender 4 to 5 cm distal to the epicondyle) and C6 radiculopathy. Medial epicondylopathy (golfer's elbow) is less common and often accompanies ulnar neuritis.

Also know olecranon bursitis (aspirate a hot one to exclude infection or gout) and radial head subluxation (nursemaid's elbow) in a toddler pulled by the hand.

Peripheral nerves of the forearm and hand

Nerve entrapments in the upper limb are high yield because they mimic cervical radiculopathy. The key is that a peripheral nerve lesion follows the nerve's cutaneous field and its muscles, while a root lesion follows a dermatome and myotome and often has neck signs and reflex change.

Carpal tunnel syndrome, the commonest entrapment neuropathy, causes numbness of the lateral three and a half digits that is worse at night and eased by shaking the hand, then thenar atrophy with weak abductor pollicis brevis. Thenar skin is spared because the palmar cutaneous branch passes superficial to the ligament; thenar numbness suggests a proximal lesion. Risk factors are pregnancy, hypothyroidism, diabetes, rheumatoid arthritis, acromegaly and repetitive use; nerve conduction studies confirm it. In a double crush, a proximal (root) compression makes the nerve more vulnerable distally.

The ulnar nerve is compressed at the cubital tunnel (most common) or Guyon canal (cyclists). A Guyon canal lesion spares dorsal ulnar hand sensation, because the dorsal cutaneous branch leaves above the wrist. Advanced palsy produces the ulnar claw. The radial nerve is compressed in the spiral groove (Saturday night palsy, wrist drop with triceps spared) or as the posterior interosseous nerve (finger drop, no sensory loss).

Wrist and hand conditions

Normal wrist motion is about 80° flexion, 70° extension, 20° radial deviation and 30° ulnar deviation. A fall on the outstretched hand (FOOSH) produces a predictable set of injuries by age: distal radius fracture in older adults, scaphoid fracture in young adults, and buckle (torus) or supracondylar fracture in children.

• Scaphoid fracture is the most commonly fractured carpal bone. Look for tenderness in the anatomic snuffbox and over the scaphoid tubercle and pain with axial thumb compression. Initial films may be normal; immobilize in a thumb spica and repeat imaging in 10 to 14 days or obtain MRI. Because the blood supply enters distally and flows retrograde, waist and proximal pole fractures risk avascular necrosis and nonunion.
• Colles fracture: distal radius with dorsal angulation and displacement (dinner fork deformity). Smith fracture: volar displacement (reverse Colles). Barton fracture: intra-articular rim fracture with carpal subluxation. Boxer's fracture: neck of the fifth metacarpal. Bennett fracture: intra-articular base of the first metacarpal; Rolando is its comminuted form.
• Gamekeeper's (skier's) thumb is a tear of the ulnar collateral ligament of the thumb MCP joint; a Stener lesion (adductor aponeurosis trapped between the torn ends) prevents healing and needs surgery.
• Finger tendon injuries: mallet finger (avulsion of the terminal extensor, DIP droops), jersey finger (avulsion of FDP, usually the ring finger, cannot flex the DIP), boutonnière deformity (central slip rupture, PIP flexion with DIP hyperextension) and swan neck deformity (PIP hyperextension with DIP flexion), the last two classic in rheumatoid arthritis.

Dupuytren contracture is painless fibrosis of the palmar fascia, forming nodules and cords that pull the ring and little fingers into MCP and then PIP flexion. It favors men of northern European ancestry over 50 and is linked to diabetes, alcohol, smoking, epilepsy and family history. The tabletop (Hueston) test is positive when the palm cannot lie flat.

Trigger finger (stenosing tenosynovitis) is thickening of the flexor tendon sheath at the A1 pulley over the metacarpal head, so a nodule on the tendon catches as it passes. The finger clicks, locks in flexion and may need to be pulled straight. The ring finger and thumb are most often involved, and diabetes and rheumatoid arthritis are risk factors.

Section 3The hip and knee

The hip

The hip is a deep ball and socket joint reinforced by the iliofemoral, pubofemoral and ischiofemoral ligaments and a labrum. Normal motion is about flexion 120°, extension 10 to 30°, abduction 45°, adduction 30°, internal rotation 35 to 40° and external rotation 45°. Intra-articular disease shows first as loss of internal rotation (capsular pattern: flexion, abduction and internal rotation limited). Hip joint pain is felt in the groin and may refer to the knee. Lateral pain over the trochanter is usually greater trochanteric pain syndrome (gluteal tendinopathy with or without bursitis).

The Trendelenburg sign is easy to get backward: standing on the right leg, a weak right gluteus medius lets the left side of the pelvis drop. A Trendelenburg gait is the dynamic version, or the patient lurches the trunk over the weak stance hip (gluteus medius lurch).

Leg length is measured from the ASIS to the medial malleolus (true or anatomic length); a difference here is structural. Measuring from the umbilicus to the medial malleolus gives apparent length, which reflects pelvic obliquity or contracture. A difference in apparent length with equal true lengths is functional.

Hip conditions by age

The knee

The ACL runs from the anterior tibia to the lateral femoral condyle and resists anterior translation and internal rotation of the tibia; the PCL, the strongest, runs from the posterior tibia to the medial femoral condyle and resists posterior translation. The MCL resists valgus and is attached to the medial meniscus, which is C shaped, less mobile and torn more often; the LCL resists varus and runs to the fibular head. Motion is 0 to about 135° flexion; the capsular pattern is flexion more limited than extension.

A classic ACL injury is a noncontact cutting or deceleration injury with a pop and hemarthrosis within hours; women are at higher risk. The unhappy triad is ACL, MCL and medial meniscus from a valgus rotation blow. A Segond fracture (lateral tibial plateau avulsion) nearly proves an ACL tear. The PCL fails in a dashboard injury. Meniscal tears give joint line tenderness, delayed swelling, catching and locking; a knee locked short of extension (bucket handle tear) needs prompt referral. A tibiofemoral dislocation threatens the popliteal artery: check pulses.

Patellofemoral tests and the extensor mechanism

The Q angle (ASIS to mid patella to tibial tubercle) is about 13° in men and 18° in women; a larger angle increases lateral patellar pull, predisposing to patellofemoral pain syndrome (anterior knee pain with stairs, squatting and prolonged sitting) and lateral dislocation.

Extensor mechanism traction problems depend on age: Osgood Schlatter disease at the tibial tubercle in adolescents, Sinding Larsen Johansson at the inferior patellar pole, and patellar tendinopathy (jumper's knee) in adults. Bursitis is named by site: prepatellar (kneeling), infrapatellar and pes anserine (under sartorius, gracilis and semitendinosus). A ruptured Baker cyst (between medial gastrocnemius and semimembranosus) mimics deep vein thrombosis.

The Ottawa knee rules call for radiographs after acute knee injury if any one of these is present: age 55 or older, isolated tenderness of the patella, tenderness of the fibular head, inability to flex to 90°, or inability to bear weight for four steps both immediately and in the clinic.

Section 4The ankle and foot

Ankle anatomy and sprains

The talus is wider anteriorly, so the ankle is most stable in dorsiflexion and least stable in plantarflexion, which is why sprains happen with the foot pointed and turned in. Motion is about 20° dorsiflexion and 50° plantarflexion, with inversion and eversion mainly at the subtalar joint.

The lateral ligament complex comprises the anterior talofibular (ATFL), calcaneofibular (CFL) and posterior talofibular (PTFL) ligaments, and an inversion sprain tears them in that order, the ATFL first. The strong medial deltoid ligament resists eversion; medial tenderness after an eversion injury should prompt a search for a fibular fracture. External rotation injures the syndesmosis (high ankle sprain), which heals slowly.

Ankle sprains are graded like other sprains: grade I stretching of the ATFL with minimal swelling and no laxity, grade II partial tear of the ATFL with or without CFL involvement, moderate swelling, ecchymosis and mild laxity, and grade III complete rupture of the ATFL and CFL with marked swelling, inability to bear weight and gross instability. Most heal with functional rehabilitation rather than prolonged immobilization.

Achilles, heel and forefoot

Achilles tendon rupture classically strikes a middle aged recreational athlete at push off: a feeling of being kicked, a palpable gap 2 to 6 cm above the insertion, and weak (not absent) plantarflexion through the toe flexors and peroneals, which is why the Thompson test matters. Risk factors include fluoroquinolones, steroid injection and prior tendinopathy.

Plantar fasciopathy is the commonest adult heel pain: pain with the first morning steps that eases with walking, and tenderness at the medial calcaneal tubercle; heel spurs are incidental. Burning sole pain suggests tarsal tunnel syndrome, and posterior heel pain at age 8 to 14 is usually Sever disease.

Morton neuroma is perineural fibrosis of an interdigital nerve, usually in the third web space, causing burning and a pebble in the shoe feeling, worse in narrow shoes. At the first MTP joint, think of hallux valgus, hallux rigidus, turf toe and gout (podagra).

Fractures and the Ottawa ankle rules

The Ottawa ankle rules are nearly 100 percent sensitive for clinically important fractures. An ankle series is indicated for malleolar zone pain plus any one of: bone tenderness at the posterior edge or tip of the distal 6 cm of the lateral or medial malleolus, or inability to bear weight for four steps both immediately and at examination. A foot series is indicated for midfoot pain plus tenderness at the base of the fifth metatarsal or the navicular, or the same weight bearing failure. They do not apply to intoxicated patients, those with reduced sensation or multiple injuries.

Section 5Diagnosis of muscle, bone and joint conditions

Sprains, strains and how to grade them

A sprain is an injury to a ligament (or joint capsule); a strain is an injury to a muscle or tendon (the musculotendinous unit). The easiest way to separate them at the bedside is selective tension. Passive movement that stretches an inert structure hurts in a sprain. Resisted isometric contraction and passive stretch of the muscle hurt in a strain. Strains occur most often at the musculotendinous junction in muscles that cross two joints and contract eccentrically, such as the hamstrings, rectus femoris, gastrocnemius and adductors.

Healing passes through inflammatory, proliferative (type III collagen) and remodeling (aligned type I collagen) phases over months. End feel is part of grading: a normal ligament has a firm, abrupt end point; a soft or empty end feel suggests rupture, and an empty end feel with severe pain but no mechanical block raises concern for acute bursitis, abscess or tumor.

Tendinopathy and bursitis

Tendinopathy is the umbrella term for painful tendon disorders; most chronic cases are degenerative tendinosis (disorganized collagen, neovascularization, few inflammatory cells), so treatment centers on progressive loading. Tenosynovitis involves the sheath (de Quervain, trigger finger), and enthesitis, inflammation at a tendon insertion, marks the spondyloarthropathies.

A bursa is a synovial lined sac that reduces friction. Bursitis gives localized tenderness and swelling over the bursa, and pain with compression or with motion of the overlying tendon. Superficial bursae (olecranon, prepatellar) swell visibly; deep bursae (subacromial, trochanteric, iliopsoas) do not. Septic bursitis (usually S. aureus, through skin breaks) produces warmth, redness, cellulitis and sometimes fever; aspiration is diagnostic, and gout and rheumatoid arthritis can also inflame bursae.

Fractures by region and the red flags

Suspect a fracture with a significant mechanism, point bone tenderness, deformity, crepitus, inability to bear weight or use the limb, and pain with axial loading, percussion or tuning fork vibration over bone. Plain films in two orthogonal views (one view is no view), including the joints above and below for long bones, are the starting point. Some fractures are occult at first: scaphoid, femoral neck, stress fractures and nondisplaced fractures in osteoporotic bone may need repeat films, MRI or bone scan.

Growth plate injuries are graded by Salter Harris (SALTR): I through the physis (S, straight), II physis and metaphysis (A, above; most common), III physis and epiphysis (L, lower; intra-articular), IV through all three (T), V crush (R, rammed; worst prognosis).

The emergencies are open fractures, fractures with vascular compromise and compartment syndrome (after tibial or forearm fractures and crush injury). Its earliest, most reliable signs are pain out of proportion to the injury and pain on passive stretch of the compartment muscles; pallor, paresthesia, paralysis and pulselessness are late. Fasciotomy is urgent.

Arthritis: reading the pattern

Sort arthritis by number of joints, which joints and symmetry, inflammatory (stiffness over an hour, raised ESR and CRP) or mechanical (stiffness under 30 minutes) behavior, and extra-articular features. A hot, swollen single joint is septic arthritis until aspiration proves otherwise (S. aureus, or gonococcus in young sexually active adults); crystals are the other main cause.

Rheumatoid arthritis also causes nodules, lung disease and Felty syndrome. Hand deformities include ulnar deviation at the MCP joints, swan neck and boutonnière deformities. The cervical spine finding that matters to a chiropractor is atlantoaxial instability from erosion or laxity of the transverse ligament; an atlantodental interval over 3 mm in an adult is abnormal, and high velocity manipulation of the upper cervical spine is contraindicated in active RA.

The seronegative spondyloarthropathies share HLA B27, enthesitis, sacroiliitis, anterior uveitis and negative RF. Ankylosing spondylitis starts in young men with inflammatory back pain that improves with exercise, a reduced Schober test (under 5 cm increase over 10 cm) and chest expansion under 2.5 cm, and a rigid spine that fractures easily. Psoriatic arthritis favors DIP joints with dactylitis and nail pitting. Reactive arthritis follows Chlamydia or enteric infection with arthritis, urethritis and conjunctivitis. Enteropathic arthritis accompanies inflammatory bowel disease.

Myofascial pain, fibromyalgia and their mimics

Myofascial pain syndrome is regional pain from trigger points: hyperirritable spots in a taut band that refer pain in a set pattern. Active points reproduce the familiar pain; latent ones hurt only when pressed. Supporting signs are a local twitch response, a jump sign and weakness without atrophy. Classic referrals: upper trapezius to the temple, infraspinatus deep into the anterior shoulder, gluteus minimus down the lateral leg (mimicking L5 radiculopathy).

Fibromyalgia is chronic widespread pain with fatigue, unrefreshing sleep and cognitive symptoms, attributed to central sensitization; it is commoner in women, coexists with IBS, headache and mood disorders, and laboratory tests are normal. The 1990 ACR criteria required widespread pain for 3 months and 11 of 18 tender points. The 2010 and 2016 criteria use the widespread pain index (WPI) and symptom severity scale (SSS): WPI 7 or more with SSS 5 or more, or WPI 4 to 6 with SSS 9 or more, generalized pain in 4 of 5 regions, for at least 3 months. Graded aerobic exercise has the best evidence.

Screen for mimics. Polymyalgia rheumatica (over 50, shoulder and hip girdle stiffness, high ESR, dramatic steroid response) coexists with giant cell arteritis in 15 to 20 percent: ask about headache, jaw claudication and vision. Polymyositis causes proximal weakness with raised CK.

When to refer

Refer or image first for suspected fracture or dislocation, neurovascular compromise, a hot joint, fever, weight loss or cancer history, unremitting night pain, progressive neurologic deficit, compartment syndrome, a locked knee, a complete tendon rupture, a limping child with limited hip rotation, and signs of giant cell arteritis.

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