2. MSK p167-180 (Soft Tissue Injury/Acquired - Upper limb) Flashcards
Wrist extensor tendon compartments
There are 6 of them.
First compartment (APL, EPB) are affected in De Quervain’s
Third compartment has EPL, which courses beside Lister’s tubercle.
Sixth compartment (ECU) can get early tenosynovitis in RA.
Carpal tunnel anatomy (6)
Lies deep to palmaris longus.
Defined by 4 bony prominences
- Pisiform
- Scaphoid tubercle
- Hook of hamate
- Trapezium tubercle
Transverse carpal ligament wraps contents in fibrous sheath
Carpal tunnel contents (7)
10 things:
- 4 flexor profundus
- 4 flexor superficialis
- 1 flexor pollicis longus
- 1 median nerve
Does NOT contain
- Flexor carpi radialis or ulnaris
- palmaris longus
- flexor pollicis brevis
Which synovial spaces usually communicate
Pisiform recess and Radiocarpal joint (either space can be used for wrist arthrography)
Which synovial spaces should NOT usually communicate (3)
GH joint and subacromial bursa - implies full thickness rotator cuff tear
Ankle joint and common (lateral) peroneal tendon sheath - implies tear of calcaneofibular ligament
Achilles tendon and posterior subtalar joint - Achilles tendon does not have a true tendon sheath
Triangular fibrocartilage tears (4)
Acute or chronic
Acute: young person with tear on ulnar side
Chronic: Ulnar abutment syndrome (positive ulnar variance with cystic change in lunate)
Degeneration of this cartilage is common (50% at age 60)
Scapholunate ligament tear (4)
Terry Thomas sign (increased SL distance on plain film).
3 parts to the SL ligament, volar, dorsal, middle.
Dorsal most important for carpal stability.
Predisposition for DISI deformity.
Keinbocks (3)
AVN of lunate, seen in 20s-40s.
Associated with negative ulnar variance.
Signal drop out on T1
De Quervain’s tenosynovitis (5)
“Washer woman’s sprain” or “Mommy thumb” due to repetitive activity/overuse.
Classically new mum holding a baby. Much more common in women.
First extensor compartment (EPB and APL) affected.
Imaging:
- US: Increased fluid within the first extensor compartment.
- MRI: Increased T2 signal in the tendon sheath
Intersection syndrome (3)
Repetitive use issue, classic in rowers.
1st extensor compartment cross over 2nd extensor compartment.
Results in extensor carpi radialis brevis and longus tenosynovitis.
Tenosynovitis (2)
Inflammation of tendon with increased fluid around the tendon.
Can be diffuse or focal
Diffuse tenosynovitis (5)
Nontuberculous mycobacterial infection:
- Hand and wrist commonly affected.
- Diffuse exuberant tenosynovitis sparing the muscles.
- Usually occurs in immunocompromised
Rheumatoid arthritis
- Multiple flexor tendons or extensor carpi ulnaris affected.
- Tenosynovitis can present as an early RA (before bone findings)
Focal tenosynovitis (4)
Overuse:
- Will be in classic locations, like 1st extensor compartment for DeQuervains
Infection
- Tenosynovitis of any flexor tendon is a surgical emergency, infection can spread rapidly to common flexors of wrist.
- Increased pressures and necrosis of tendons
- Delayed treatment tend to do terribly.
Dupuytren contracture (4)
Most common fibromatosis.
Classically white person with alcoholic liver disease.
Nodular mass on palmar aspect of aponeurosis, progressing to cord like thickening and contracture. Usually involves 4th finger.
50% are bilateral.
Finger tumours (9)
Scalloping on plain film. MRI needed for a specific diagnosis
Glomus tumour
- Benign vascular tumour seen at tips of fingers (75% in hands).
- T1 dark, T2 bright, avid enhancement.
Giant Cell Tumour of Tendon Sheath
- basically PVNS of tendon.
- Usually palmar tendons of hand.
- Can erode underlying bone.
- Soft tissue density, T1 and T2 dark, blooming on gradient.
Fibroma
- Benign overgrowth of tendon collagen.
- Low T1 and T2, will NOT bloom like GCT.
Cubital Tunnel Syndrome (3)
Result of repetitive valgus stress.
Ulnar nerve passes beneath cubital tunnel retinaculum, aka epicondylo-olecranon ligament or Osborne band.
Due to compression by any pathology (tumour, haematoma, accessory muscle (classically anconeus epitrochlearis)
Partial Ulnar Collateral Ligament Tear (3)
Throwers (valgus overload) hurt their ulnar collateral ligament (attaches to medial coronoid - sublime tubercle).
UCL has 3 bundles, anterior bundle is most important.
Partial UCL tear demonstrates T sign, with contrast extending medially to the tubercle.
Panner disease (3)
Osteochondrosis of capitulum.
Seen in 5-10YO kids, thought to be related to throwing.
Looks like OCD affecting the elbow (also favours capitulum).
Panner vs OCD (4)
Both favour capitulum.
Both demonstrate low T1 and high T2.
Panner affects age 5-10, no loose bodies.
OCD affects teenagers, has loose bodies.
Lateral epicondylitis (3)
Tennis elbow.
More common than medial.
Extensor tendon injury, classically extensor carpi radialis brevis)
Radial collateral ligament complex - tears due to varus stress.
Medial epicondylitis (2)
Golf elbow.
Common flexor tendon and ulnar nerve may enlarge from chronic injury.
Epitrochlear lymphadenopathy
Classic look for cat scratch disease.
Dialysis elbow (2)
Olecranon bursitis due to constant pressure on the area.
Related to arm positioning during treatment.
Impingement/rotator cuff tears (4)
Rotator cuff pathology is usually result of overuse (sports) or impingement mechanisms.
2 Main types of impingement with 2 major subdivisions:
External
- Primary
- Secondary
Internal
- Posterior superior
- Anterior superior
External rotator cuff impingement - definition
Impingement of rotator cuff overlying the bursal surfaces (superficial surfaces) adjacent to acromial arch.
Arch is made up of coracoid process, acromion, and coracoacromial ligament.
External rotator cuff impingement - types (4)
Primary (abnormal coracoacromial arch):
- Hooked acromion (type III Bigliani) more associated with external impingement than curved or flat types.
- Subacromial osteophyte formation or thickening of coracoacronial ligament
- Subcoracoid impingement: Impingement of subscapularis between coracoid process and lesser tuberosity. Can be due to congenital configuration or post traumatic after fracture of coracoid or lesser tuberosity
Secondary (normal coracoacromial arch):
- Multidirectional glenohumeral instability: Micro-subloxation of the humeral head in the glenoid leads to repeated microtrauma. Usually seen in patients with generalised joint laxity, often involves both shoulders.
Internal rotator cuff impingement - definition
Impingement of rotator cuff on undersurface (deep surface), along glenoid labrum and humeral head.
Internal rotator cuff impingement - types (5)
Posterior superior:
-Posterior superior rotator ciff (junction of supra and infraspinatus tendons) comes into contact with posterior superior glenoid
- Best seen in ABER position, tendons pinched between labrum and GT.
- Seen in athletes who make overhead movements (tennis, swimming, throwers)
Anterior superior
- Internal impingement when the arm is in horizontal adduction and internal rotation.
- Undersurface of biceps and subscapularis tendon may impinge against anterior superior glenoid rim.
Subacromial impingement (3)
Most common form
Results from attrition of coracoacromial arch.
Damages supraspinatus tendon
Subcoracoid impingement (2)
Lesser tuberosity and coracoid do the pinching.
Damages subscapularis
Posterior superior internal impingement (3)
Athletes who make overhead movements
GT and posterior inferior labrum do the pinching
Damages infraspinatus and posterior fibres of supraspinatus.
Rotator cuff tears (6)
Tear of articular surface is 3x more common than bursal.
Usually degenerative, but trauma can play a role.
Supraspinatus tear is commonest.
Teres minor is least common.
Partial tear of >50% is important to surgeons.
Tear of fibrous rotator cuff interval is still considered a rotator cuff tear.
Massive rotator cuff tear
at least 2 of 4 rotator cuff muscles torn
Full thickness rotator cuff tear - imaging (2)
high T2 signal in expected location of tendon.
Gadolinium in the bursa on T1
SLAP (Superior Labral Anterior Posterior) tear (7)
Superior glenoid labral tears which track anterior to lateral.
Tear involves the labrum at the insertion site of long head of biceps. Therefore injury to this tendon is associated and part of the grading system (type 4).
When SLAP extends to biceps anchor, surgical management changes from debridement to debridement + biceps tenodesis.
Mechanism is usually overhead movement (classically swimmer).
People over 40 usually have associated rotator cuff tear
NOT usually associated with instability.
SLAP mimic (3)
Sublabral recess.
Essentially normal variant. Incomplete attachment of the labrum at 12 O’clock, which typically has the worse blood supply.
Follows contour of glenoid and has smooth margin, whereas SLAP extends laterally and has rough margin.
Labral tear mimic - sublabral foramen (2)
Unattached but present portion of the labrum, located at anterior-superior labrum (1 o’clock to 3 o’clock).
Should NOT extend below the equator (3 o’clock)
Labral tear mimic - Bulford complex (2)
Another variant, present in 1% of population.
Absent anterior/superior labrum (1 o’clock to 3 o’clock) with thickened middle glenohumeral ligament.
Bankart lesions - a spectrum (5)
GLAD (Glenolabral Articular Disruption)
- Superficial partial labral tear with associated articular cartilage defect.
- No instability. Common in sports
Perthes
- Avulsed anterioinferior labrum (3-6 o’clock), medially stripped but intact periostium.
- Inferior GH complex still attached to periostium.
ALPSA
- Like Perthes with bunched up medially displaced inferior GH complex.
- Intact periostium
Bankart (cartilaginous)
- Torn labrum, periostium disrupted.
Banklart (osseous)
- Fractured glenoid fossa
HAGL (3)
Humeral avulsion glenohumeral ligament.
Avulsion of the inferior glenohumeral ligament, often due to anterior shoulder dislocation.
J sign: normal U shaped inferior glenohumeral recess is retracted away from the humerus, causing J shape.
Subluxation of biceps tendon (3)
As the subscapularis attaches to lesser tuberosity, it sends some fibres across the bicipital groove to the GT, called the transverse ligament.
Subscapularis tear opens these fibres up, allowing the biceps to dislocate (usually medially).
Subscapularis tear = medial dislocation of the long head of biceps tendon.
Suprascapular notch vs spinoglenoid notch (2)
Cyst at the level of the suprascapular notch will affect supraspinatus and infraspinatus.
Cyst at the level of spinoglenoid notch will only affect infraspinatus.
Quadrilateral space syndrome (6)
Compression of the axillary nerve in the quadrilateral space, usually from fibrotic bands.
Associated with atrophy of teres minor.
Borders of the quadrilateral space:
- Teres minor (superiorly)
- Teres major (inferiorly)
- Humeral neck (lateral)
- Triceps (medial)
Parsonage-turner syndrome (2)
Consider when muscles affected by pathology in 2 or more nerve distributions.
Idiopathic involvement of brachial plexus.
