Musculoskeletal Flashcards
1
Q
Helpful videos
A
BONE AND CARTILAGE TUMOURS https://www.youtube.com/watch?v=wezFzUX-UWY
METABOLIC BONE DISEASE
https://www.youtube.com/watch?v=dmkuUXOZ4EQ
OSTEOPOROSIS
https://www.youtube.com/watch?v=jUQ_tt_zJDo
OA
https: //www.youtube.com/watch?v=sUOlmI-naFs
https: //www.youtube.com/watch?v=sUOlmI-naFs&t=23s
RA
https://www.youtube.com/watch?v=EB5zxdAQGzU
BONE TUMOURS
https://www.youtube.com/watch?v=MgWRqBtXzI0
2
Q
Fracture vocab
A
STRESS
Fatigue: abnormal stress on normal bone (cross country runner)
Insufficiency: normal stress on abnormal bone (osteoporotic)
PATHOLOGIC
Fracture through lytic/sclerotic bone lesion.
OPEN/COMPOUND
Fracture associated with open wound.
3
Q
Fracture healing
A
BONE HEALING Inflammatory, reparitive and remodelling phases. At days 7-14 there is granulation tissue between bone fragments making bone more lucent. Phalanges heal 3 weeks Most things heal 6-8 weeks Tibia heals 10 weeks
DELAYED
Fracture not healed within expected time frame (usually twice as long as expected)
NON UNION
Fracture not going to heal without intervention, usually 6-9 months
MALUNION
Union in poor anatomic position
RISK FACTORS FOR DELAY
Vit D deficiency (vital role in calcium uptake and metabolism). Gastric bypass alters calcium resorption causing secondary hyperparathyroidism. Drugs/meds such as tobacco, NSAIDS and steroids.
4
Q
Compressive vs tensile side
A
Fractures of compressive side of bone are compressed together and do well with healing. Eg posterior tibial shaft or medial femoral neck
Fractures of tensile side are pulled apart and dont heal well. Eg anterior tibia and lateral femoral neck
5
Q
SONK
A
Spontaneous osteonecrosis of the knee.
Incorrectly named, actually insufficiency fracture of femoral condyle. Old ladies with sudden rising from chair etc. Favors medial femoral condyle (maximum weight bearing). Unilateral in old lady without trauma. ssociated with meniscal injury. Lots of oedema
6
Q
Classic stress fractures
A
CALCANEAL
Most fractured tarsal bone, usually intra-articular. Stress fracture will have fracture lines perpendicular to trabecular lines.
NAVICULAR
Runners who run on hard surfaces. High risk AVN
MARCH
Metatarsal stress fracture. Military recruits marching all day.
7
Q
High vs low risk stress fractures for healing
A
HIGH RISK Femoral neck tensile side Transverse patella Anterior tibial 5th metatarsal talus Tarsal navicular Sesamoid great toe
LOW RISK Femoral neck compressive side Longitudinal patella Posteromedial tibia 2nd and 3rd meatarsal calcaneus
8
Q
Scaphoid fracture
A
Most common carpal fracture. Adolescents and young adults. Blood flow retrograde due to cartilage covering of majority of bone. Proximal at risk for AVN (first sign sclerosis) and non union. Usually fracture at waist.
TRANS SCAPHOID PERILUNATE
Perilunate dislocation have high association with scaphoid fracture 60%
SCAPHOLUNATE LIGAMENT DISRUPTION
Gap of >3mm. Seen in 10-30% distal radial/carpal fractures. SL ligament has 3 bands, volar dorsal and middle. Dorsal is most important for stability. Disruption predisposes to DISI deformity.
HUMPBACK DEFORMITY
Angulation of proximal and distal fragments in setting of waist fracture. Can progress to collapse and non union. Associated with DISI
9
Q
SLAC and SNAC
A
SCAPHOID-LUNATE ADVANCE COLLAPSE
Occurs with injury to the SL ligament (or degeneration via CPPD)
SCAPHOID NON-UNIONADVANCED COLLAPSE
Occurs with scaphoid fracture
Scaphoid always wants to rotate in flexion, SL only thing preventing this. If this ligament breaks scaphoid goes into flexion and messes up dynamics. Radioscaphoid first to develop degenerative change. Capitate will migrate proximally and eventual DISI deformity
10
Q
Scapholunate ligament tear
A
Terry Thomas on XR. SL has volar, middle and dorsal with dorsal band being most important for carpal stability. If tear, carpal bones will migrate away from each other.
Predisposes to DISI deformity.
11
Q
DISI vs VISI
A
DORSAL INTERCALATED SEGMENTAL INSTABILITY
Dorsiflexion instability. After radial sided injury (scapholunate side) the lunate becomes free of stabilizing force of the scaphoid and rocks dorsally. More common as SL tear is common. Widening of SL angle with dorsiflexion of lunate. Angle >60 degrees.
VOLAR INTERCALATED SEGMENTAL INSTABILITY
Volar flexion instability. After ulnar sided injury (lunotriquetral side) the lunate no longer has stablizing force of LT ligament and gets ripped volar with scaphoid. Uncommon. Narrowing of SL angle with volar flexion of lunate and scaphoid. Angle <30
12
Q
Carpal dislocations
A
SL DISSOCIATION
SL >3mm. Clenched fist view can worsen. Chronic SL dissociation can cause SLAC wrist.
PERILUNATE DISLOCATION
Lunate stays put and bones around it dislocate dorsally. 60% scaphoid fracture associated.
MID CARPAL DISLOCATION
Both lunate and capitate lose radial alignment. Associated with triquetro-lunate interosseous ligament disruption. Associated with triquetral fracture.
LUNATE DISLOCATION
Lunate dislocates volar, others stay in normal alignment. Most severe. happens with dorsal radiolunate injury.
13
Q
Synovial spaces trivia
A
GLENOHUMERAL JOINT AND SUBACROMIAL BURSA
Should not communicate, implies full thickness cuff tear
ANKLE JOINT AND COMMON PERONEAL TENDON SHEATH
Should not communicate, implies tear of calcaneofibular ligament
ACHILLES TENDON AND POSTERIOR SUBTALAR JOINT
Should not communicate. Achilles tendon does not hav true tendon sheath
PISIFORM RECESS AND RADIOCARPAL JOINT
Should communicate and can use either for arthrography.
14
Q
TFCC
A
Primary stabilizer and shock absorber of distal radiolnar joint DRUJ.
5 COMPONENTS Triangular fibrocartilage (articular disc) Volar and dorsal radioulnar ligaments Meniscus homologue UCL Tendon sheath of ECU
TFCC INJURIES
Acute: fall onto extended wrist
Chronic degeneration: More common and involved with positive ulnar variance and ulnar impaction.
Ulnar sided injuries more likely to heal due to better vascularity.
15
Q
Ulnar variance
A
Can occur congenitally or be acquired from impaction/fracture
POSITIVE
Ulnar impaction syndrome (ulnolunate). Get cystic change in lunate and TFCC tears
NEGATIVE
Get AVN of lunate (Kienbock). Sclerotic XR and low T1 MRI
16
Q
Distal radius fractures
A
COLLES
Distal metaphysis fracture, extra-articular with dorsal angulation. Dinner for deformity. Old lady fracture. Ulnar styloid fracture commonly associated.
SMITH
Distal metaphysis fracture, extra-articular with volar angulation. Younger patient, ulnar styloid fracture associated. Intra-articular variant called reverse Barton. Can result in carpal tunnel if residual volar angulation.
BARTON
Intra-articular dorsal radius fracture ‘radial rim’. Fracture involves either dorsal radius or volar radius (more common). Radiocarpal dislocation is hallmark. Surgical repair with high rate redislocation and mal-union.
HUTCHINSON/CHAUFFER
Intra-articular fracture of radial styloid. Association with SL dissociation and perilunate dislocation
17
Q
Radial tilt
A
Normal radial tilt of about 11 degrees. Usually wont accept past neutral. True lateral to measure.
18
Q
Delayed EPL rupture after radial fracture
A
Distal radial fracture can alter morphology of Listers tubercle (dorsal aspect separating 2nd and 3rd extensor compartment) and result in delayed rupture EPL. More common after non displaced fracture.
19
Q
Extensor tendons
A
6 extensor compartments
First compartment (APL and EPB) are affects in de Quervains
Third compartment has EPL which courses by Listers tubercle and can rupture after fracture.
Sixth compartment (ECU) can get an early tenosynovitis in RA
20
Q
Carpal tunnel
A
Bounded by pisiform, scaphoid tubercle, hamate hook and trapezium tubercle. Transverse carpal ligament overlies. 4 x FDP 4 x FDS 1 x FPL 1 x Median nerve
NOT IN TUNNEL
FCR, FCU, PL, FPB
21
Q
Carpal tunnel syndrome
A
Median nerve distribution, often bilateral, may have thenar muscle atrophy. Enlargement of nerve on USS. Usually from repetitive trauma but can be from dialysis, pregnancy, DM and hypothyroidism. May have increased signal in nerve or it may look swollen/smashed/flattened. Bowing of flexor retinaculum.
22
Q
Guyons canal syndrome
A
Entrapment of ulnar nerve as it goes through Guyons canal (formed by pisiform and hamate). Handle bar palsy. Fracture of hook of hamate can also cause this.
23
Q
Sub sheath tear/dislocation
A
Traumatic dislocation to ECU (compartment 6) out of its normal groove at level of distal ulna. Subluxation implies rupture of overlying sheath. Medial dislocation
24
Q
Vaughan Jackson syndrome
A
Sequential extensor tendon ruptures seen in worsening RA of DRUJ. Progresses ulnar to radial starting at 5 EDM (-4-3-2)
25
Tenosynovitis
Inflammation of tendon manifesting as increased fluid around tendon.
DIFFUSE
TB OR NON TB MYCOBACTERIAL
Hand and wrist most common. Diffuse and exuberant, spares muscles. Immunocompromised. Rice body in TB
RHEUMATOID
Multiple flexor tendons or isolated ECU. Vughan Jackson syndrome as above. Can present before bone findings
FOCAL
PENETRATING INFECTION
Surgical emergency as can spread rapidly to common wrist flexors. Increased pressure in sheath can cause necrosis of tendons. Delayed treatment do bad.
OVERUSE
DEQUERVAINS
Mommy thumb. New mom holding baby. First extensor compartment EPB and APL. Increased fluid in first compartment. Pain on passive ulnar deviation
INTERSECTION SYNDROME
Repetitive use seen in rowers. Fist extensor tendons intersect second extensory compartment tendons. ECR brevis and longus tenosynovitis.
DRUMMER WRIST
Tenosynovitis of third compartment EPL.
26
Bennett and Rolando fractures
Fractures of base of first metacarpal. Rolando fracture is comminuted, Bennett isnt. Pull of APL is what causes dorsolateral dislocation in Bennett.
27
Gamekeepers thumb
Avulsion fracture at base of proximal first phalanx associatwd with UCL disruption. Stener lesion is when adductor tendon aponeurosis gets caught in torn edges of UCL - displaced ligament wont heal right and need an operation. Yoyo appearance on MRI
28
Trigger finger
Overuse/repetitive trauma causes scarring in flexor tendon sheath. Stenosing tenosynovitis. Thick sheath
29
Forearm fractures
MONTEGGIA (MUGR)
Fracture of prox ulna with anterior dislocation radial head.
GALLEAZI (MUGR)
Radial shaft fracture with DRUJ dislocation
ESSEX LOPRESTI
Fracture of radial head and anterior dislocation at DRUJ. Unstable fracture with rupture of interosseous membrane.
30
Cubital tunnel syndrome
Several causes, most commonly repetitive valgus stress. On MCQ answer is accessory aconeus.
Anconeus is muscle on lateral elbow which doesnt do much. Can have accessory muscle (anconeus epirochlearis) on medial elbow which will compress ulnar nerve. Site where ulnar nerve passes beneath cubital tunnel called epicondylo-olecranon ligament or Osbornes ligament
31
Epicondylitis
LATERAL (Tennis elbow)
More common. Repetitive extension. Extensor tendon injury (ECRB). Radial collateral ligament tears due to varus stress
MEDIAL (Golfers elbow)
Repetitive flexion. Common flexor tendon and ulnar nerve may enlarge from chronic injury
32
Partial ulnar collateral ligt tear
Throwers and people with valgus overload get these. Ulnar collateral ligt attaches on medial coronoid at sublime tubercle.
Ligament has 3 bundles with anterior most important. Partial UCL tear gets "T sign" with fluid extending medial to tubercle.
33
Little leaguer elbow
Repetitive chronic injury to medial epicondyle. Stress fracture, avulsion or delayed closure of medial epicondylar apophysis. Usually associated with UCL injury.
Valgus overload syndrome is seen in throwers and consists of lateral compression, medial tension and posterior sheer. Results in UCL injury, arthritis at posterioe humerus/ulna and OCD at capitellum
34
Random elbow
EPITROCHLEAR LYMPHADENOPATHY
Classic look for cat scratch disease.
DIALYSIS ELBOW
Olecranon bursitis from constant pressure on area relating to positioning of arm during treatment
35
Biceps tear
Partial or complete. Complete tear usually occurs in shoulder with avulsion off labrum or in bicipital groove.
PARTIAL TEAR
Often associated with bicipitoradial bursitis. Painful mass antecubital fossa. Popeye deformity.
36
Triceps rupture
Least common tendon in body to rupture. Tenidnopathy fairly uncommon also. Salter Harris 2 fracture of olecranon is classic scenario.
Mimics include striated appearance of insertion at olecranon and olecranon bursitis.
37
Elbow dislocation
Second most commonly dislocated joint in adult. Usually associated with radial head and coronoid process fracture.
Instability in the elbow (posterior rotary instability) is described in a pattern starting in posteriolateral corner with tearing of lateral UCL.
38
Shoulder dislocation
ANTEROINFERIOR
Most common 90%. Hill Sachs posterolateral humerus best seen on internal rotation. Bankart on anteroinferior labrum. GT avulsion in 10% dislocation in >40yo.
POSTERIOR DISLOCATION
Uncommon. Seizure, electrocution. Rim sign is no overlap between glenoid and humeral head. Trough sign is reverse Hillsachs with impaction on anterior humerus. Light Bulb sign is arm locked in internal rotation on all views
INFERIOR DISLOCATION
Luxatio erecta. Uncommon. Arm sticking up. 60% get neurologic injury.
39
Proximal humerus fracture
Old lady FOOSH. Neer classification for how many parts humerus is in. Treat 3 or 4 part wit reverse TSJR
40
Post op shoulder
4 TYPES
Humeral head resurfacing, hemiarthroplasty, TRJR and RTSJR
INTACT CUFF
If glenoid intact get resurfacing or hemi.
If glenoid deficient get TSJR
CUFF TRASHED
If glenoid intact get hermi or RTSJR
If glenoid deficient get RTSJR
COMPLICATIONS/TRIVIA
Most common complication of TSJR is loosening of glenoid component and anterior escape following subscapularis failure.
RTSJR heavily relies on deltoid. Posterior acromion fracture from excessive deltoid tugging can occur.
41
Impingement
Overuse. 2 types with 2 subdivisions
EXTERNAL PRIMARY (abnormal coracoacromial arch)
Hoked acromion
Subacromial osteophyte
Thickening subacromial ligament
Subcoracoid impingement (of subscap between coracoid process and LT) either congenital or post traumatic
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EXTERNAL SECONDARY (normal coracoacromial arch)
Multidirectional glenohumeral instability resulting in microsubluxation and repetitive microtrauma. Generally bilateral and with joint laxity. Increase shoulder volume with injection.
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INTERNAL POSTERIOR SUPERIOR
Junction of supra and infra tendons contacts posterosuperior glenoid and gets pinched between labrumand GT. Athletes with overhead movements. Abd ext rot position.
INTERNAL ANTERIOR SUPERIOR
Abd and int rot. Undersurface of biceps and subscap impinge against anterior superior glenoid rim.
42
Impingement cont
SUBACROMIAL IMPINGEMENT most common resulting from attrition or coracromial arch. Damages supraspinatus tendon.
SUBCORACOID IMPINGEMENT lesser tuberosity and coracoid do pinching, damages subscapularis
POSTEROSUPERIOR INTERNAL impingement is athletes with overhead movements. Greater tuberosity and posterosuperior labrum do pinching, damages infraspinatus and posterior fibres supraspinatus.
43
Rotator cuff tears
Bursal side (top) or articular side (undersurface). Articular surface 3x more common. Underlying mechanism usually degenerative.
Most common is supraspinatus with tear usually at critical zone 1-2cm from footprint. Avascular here and common location for HADD or calcific tendinitis. Teres Minor least common to tear.
Partial tear >50% often needs fixing. Massive rotator cuff tear refers to at least 2/4 rotator cuff tendons tearing.
Tear of rotator cuff interval (junction between anterior fibres of supraspinatis and superiro fibres of subscap) still considered cuff tear.
If full thickness, will get gad in bursa on T1 C+
44
Adhesive capsulitis/frozen shoulder
Inflammatory condition with global decrease in ROM. Can have primary but mcq will always be trauma or surgery. Most commonly affects rotator cuff interval. T1 or non fat sat T2 will show loss of fat in rotator cuff interval with thickening of axillary fold
Decreased glenohumeral volume with injection. Thickened inferior and posterior capsule. Enhancement of rotator cuff interval post gad
45
SLAP tears
Labral tears favour superior margin and track anerior to posterior. Involves insertion of long head biceps.
When extends to biceps anchor (type 4) surgical management changes. Mechanism usually overhead movement (swimmer). Age >40 often have associated cuff tear. NOT associated with instability. Extends laterally with ratty margin. Located at biceps anchor and posteriorly
46
Tear mimics
SLAP MIMIC - sublabral recess
Normal variant with incomplete attachment of labrum at 12oclock. This position has worst blood flow. Follows contour of glenoid with smooth margin. Located at biceps anchor
LABRAL TEAR MIMIC - sublabral foramen
unattached portion of labrum and anterosuperior labrum 1-3oclock. Should not extend below 3oclock
LABRAL TEAR MIMIC - buford complex
1% population. Absent anterior/superior labrum 1-3oclock with thickened middle glenohumeral ligament.
47
Bankart lesions (seen with anterior dislocations)
GLAD
Glenolabral articular disruption. Most mild. Superficial anterior inferior labral tear with associated cartilage damage. No instability. Common in sports.
PERTHES
Detachment of anteroinferior labrum 3-6oclock with medially stripped but intact periosteum.
ALPSA
Anterior labral periosteal sleeve avulsion. Medially displaced labroligamentous complex with absence of labrum on glenoid rim. Intact periosteum.
TRUE BANKART
Cartilagenous or osseous. Periosteum disrupted.Often Hill Sachs.
48
Posterior glenohumeral instability
REVERSE BANKART
Fracture of posterior inferior rim of glenoid
POLPSA
Posterior labrum and posterior scapular periosteum are stripped from gelnoid resulting in recess that communicates with joint space
BENNETT LESION
Extra-articular curvilinear calcification associated with posterior labral tears. Related to injury of posterior band of inferior glenohumeral ligament.
KIMS LESION
Incompletely avulsed/flattened/mashed posterior inferior labrum. Glenoid cartilage and posterior labrum relationship is preserved.
49
HAGL
Humeral avulsion glenohumeral ligament. Avulsion of inferior glenohumeral ligament and usually as result of anterior shoulder dislocation. J sign when normal U shaped inferior glenohumeral recess is retracted from humerus and looks ike a J.
50
Subluxed biceps tendon
Subscapularis attaches to LT and sends a few fibres accross bicipital groove to GT, called transverse ligment. Tear of subscap often opens these fibres and allows biceps to dislocate. Get medial dislocation of biceps
51
HAGL
Humeral avulsion glenohumeral ligament. Non-bankart lesion. Result of anterior shoulder dislocation. J sign when normal U shaped inferior glenohumeral recess is retracted from humerus.
52
Subluxed biceps tendon
Subscap attaches to LT and sends a few fibres across bicipital groove to GT called transverse ligament. Tearing subscap opens these up and medialises biceps tendon.
53
Nerve entrapment at shoulder
SUPRASCAPULAR NOTCH
Affects supraspinatus and infraspinatus
SPINOGLENOID NOTCH
Affects infraspinatus
54
Quadralateral space syndrome
Borders are: humerual shaft, teres minor, teres major and long head triceps. Axillary nerve runs through here and can be compressed. Atrophy of teres minor.
55
Parsonage Turner syndrome
Idiopthic involvement of brachial plexus. Think of it when muscles affected by pathology in 2 or more distributions (axillary and suprascapular etc).
56
Femoral shaft fractures
Medial is classic stress location. Lateral is classic bisphosphanate location (cortical thickening)
57
Hip fracture/dislocation
Posterior dislocation most common with dashboard injuries, usually fractured acetabulum, foot internal rotation.
Acetabulum supported by two columns of bone (ant and post) which merge to form inverted Y. Both column fracture divides ileium proximalto hip joint so have no aticular surface of hip attached to axial skeleton.
Corona mortis is anastamosis of inferior epigastric and oburator vessels. Sometimes rides on sup pub ramus. Can be injured during lateral dissection.
Hip fracture leading to AVN. Femoral head gets blood from circumflex femorals so displaced intracapsular fracture can compromise this.
58
Hip avulsions
Seen more in kids as tendons stronger than bones, other way around in adults.
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ILIAC CREST abdominal muscles
ASIS sartorius, tensor fascia lata
AIIS rectus femoris
GT gluteal muscles
PUBIC SYMPHYSIS adductors
ISCHIAL TUBEROSITY hamstrings
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LT iliopsoas - isolated avulsion in adult think pathological fracture
59
Snapping hip
Clinical sensation. 3 types
EXTERNAL (evaluate clinically)
iliotibial band over GT
INTERNAL (evaluate with USS cine)
iliopsoas over iliopectineal eminence or femoral head
INTRA-ARTICULAR (evaluate with MRI)
labral tears/joint bodies
60
IT band syndrome
Repetitive stress. Fluid on both sides of IT band
61
Hip labrum
Anterior superior tears most common. Paralabral tears associated with tears. Intra-articular contrast will increase sensitivity
62
Iliopsoas bursa
Fluid signal anterior to femur adjacent to psoas tendon at level of ischial tuberosity.
Largest bursa in body. Communicates with joint in 15%. Anterior to hip. Iliopsoas tendon runs anterior to labrum on axial and can mimic tear.
63
Femoroacetabular impingement
Painful hip movement. Two types
CAM TYPE
Osseous bump at femoral head/neck junction. More common in athletic males.
PINCER TYPE
Deformity of acetabulum. Middle aged women. Cross over sign on radiograph where posterior lip crosses over anterior lip by superolateral acetabulum. Associations include coxa profunda, acetabular protrusion and prominent ischial spine.
Get os acetabuli, labral tears and early arthritis
64
THJR
STRESS SHIELDING
Stress transferred through stem so bone around it unloaded and resorbed. More with uncemented. Can predispose to fracture. Can get stress loading inferiorly
HETEROTOPIC OSSIFICATION
Common and usually asymptomatic. Hip stiffness is complaint.
ASEPTIC LOOSENING
Most common indication for revision. >2mm at interface. Can call if see migration of component.
SUBSIDENCE
Arthroplasty sliding downwards. Early failure. See with implants without collar.
WEAR/CREEP
Normal to have a little thinning of liner in area of weightbearing (creep) but not normal at superolateral aspect (wear)
PARTICLE DISEASE
Aggressive granulomatosis. If device sheds it causes inflammatory reaction. Wear is primary underlying factor. Progressive lytic focal regions around replacement and joint effusions. Most commonly in uncemented, see 1-5 yeas after surgery,smooth endosteal scalloping, ESR and CRP normal, no secondary bone response, can see around screw holes.
65
Sacrum
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Usual pathologies shown will be:
SIJ degenerative change
Unilateral SIJ infection
Chordoma
Sacral agenesis
Insufficiency fracture
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SACRAL INSUFFICIENCY FRACTURE
Most common is postmenopausal osteoporosis. Can get in renal failure, RA, pelvic radiation, mechanical changes after hip arthroplasty or steroid use. Will usually show Honda sign on bone scan.
66
Site specific entities
SEGOND FRACTURE
Lateral tibial plateau capsular avulsion fracture. ACL 75%. Occurs with internal rotation.
REVERSE SEGOND
Capsular avulsion medial tibial plateau. External rotation. Associated with PCL and MCL.
ARCUATE SIGN
Avulsion prox fibula (insertion of arcuate ligament complex). 90% associated with cruciate ligament injury usually PCL
DEEP INTERCONDYLAR NOTCH SIGN
Depression of lateral femoral condyle on lateral image secondary to impaction fracture. Associated with ACL.
67
Knee ligaments
ACL: Composed of 2 bundles, anteromedial and posterolateral. Tibial attachment thicker than femoral attachment. Both ACL and PCL are intra-artcular and extrasynovial.
PCL: strongest ligament in the knee.
MCL: fibres laced into the joint capsule at level of joint with connection to medial meniscus. MCL is extra-articular.
CONJOINT TENDON: formed by biceps femoris and LCL.
IT band inserts onto Gerdys tubercle on lateral proximal tibia.
68
Magic angle
Seen on images with short echo time (TE) when tendons form angles at 55 degrees from main magnet. Goes away on T2. Also reduced at higher field strengths due to greater shortening of T2 relaxation times.
69
ACL
TEAR
People stopping and pivoting. Associated with Segond facture and tibia spine avulsion. ACL angle less than Blumensaats line. O'donoghues unhappy triad of ACL, MCL and medial meniscus. Kissing contusion bone marrow oedema.
MUCOID DEGENERATION
Can mimic acute or chronic partial tear.No secondary signs of injury. Predisposes ACL to ganglion cysts. Cleery stalk on T2/FLAIR. T1 is drumstick.
70
ACL repair
Can be fixed in two ways: Using middle third of patellar tendon with a patella bone plug attached to one end and and tibial bone plug at the other. Can use graft of semitendinosus, gracilis or both graft then attached to bolts etc.
GRAFT EVALUATION
Tibial tunnel: should parallel roof of femoral intercondylar notch. Too steep will impinge by femur on extension, too shallow wont provide stability, too anterior can pinch.
Femoral tunnel: primary factor for maintaining length and tension during range of motion.
ARTHROFIBROSIS
Focal or diffuse. Focal form is cyclops lesion (scar associated with ventral graft). Low signal mass in Hoffas fat pad. Limits extension.
GRAFT TEAR
Flat angle is tear. ACL should parallel roof of intercondylar notch. Most susceptible to tear in remodelling process 4-8 months post op. High T2 signal, fibre discontinuity, uncovering of posterior horn of lateral meniscus, anterior tibial translation.
71
Posterolateral corner and PCL
Complex anatomy. Think LCL, ITB, BF and popliteus tendon. Oedema in fibular head.
PCL TEAR
Strongest ligament in knee. Tear is uncommon, more likely to stretch and appear thickened. If tear think posterior dislocation. If tear need to look at popliteal flow void
72
Meniscal tears
Peripheral third (red zone) has better vasculature than inner 2/3 (white zone) and bigger chance of healing on its own.
RADIAL
Vertical. Bad as cuts circular hoop fibres that hold meniscus together.Can lead to extrusion, early OA. Usually see either truncated triangle, cleft or ghost (absent triangle)
FLAP TEAR
Vertical radial that changes direction into longitudinal direction. Parrot Beak
LONGITUDINAL
Can be vertical or horizontal or mixed. Long extension in axial direction. Vertical types can flip and become bucket handle
HORIZONTAL CLEAVAGE
Pure cleavage tears extend to apex. Associated with meniscal cysts. Most common posterior horn medial meniscus
73
Bucket handle tear
80% in medial meniscus. Vertical longitudinal which flips and has component in notch, anterior to PCL. Shown as double PCL sign. Can also be shown as not enough bow ties on sag.
Double PCL sign can only occur in setting of intact ACL
74
Discoid meniscus
Normal variant of lateral meniscus that is prone to tear. Not C shaped but instead shaped like a disc. Too many bowties (3 or more).
Paediatric patient with meniscal tear. 3 types, most rare and prone to injury is Wrisberg variant.
75
Meniscal things
MENISCAL CYST
Most often laterally and associated with horizontal cleavage tears.
MENISCOCAPSULAR SEPARATION
Rare injury. Deepest layer of MCL complex (capsular ligament) is relatively weak and first to tear. Deep tearing results in separation of meniscus and MCL. Happens more with proximal MCL tears and requires immobilization or surgery.
MENISCAL OSSICLE
Focal osssification of posterior horn medial meniscus secondary to trauma or congenital. Usually associated with radial root tears.
MENISCOFEMORAL LIGAMENTS
Wrisberg and Humphrey. Wrisberg is most posterior, Humphrey is anterior
MENISAL FLOUNCE
Ruffled appearance of meniscus that mimics tear.
76
Patella dislocation
Usually lateral. Classic contusion pattern (medial patella facet, lateral femoral condyle). Associated tear of MPFL. Associated with trochlear dysplasia (too flat)
77
Patella alta/baja
ALTA
Patella tendon tear, unopposed pull from quads and patella moves up. Classic is with SLE and can be in elderly, trauma, athletes and RA.
BAJA
Quad tendon tear, unnoposed pull from patella tendon and patella moves down.
Fat impingement syndrome is high T2 signal in Hoffas fat pad inferior to patella.
Jumpers knee is high T2 signal and thickening of patella ligament
78
Tibial fractures (and Maisonneuve)
TIBIAL PLATEAU
Usually axial loading and more common lateral plateau. If medial, usually bilateral. Schatzker system with 2 most common (split and depressed lateral plateau).
PILON (TIBIAL PLAFOND)
Usually axial loading. Talus driven into tibial plafond. Comminution and articular impaction. 75% will also fracture distal fibula
TIBIAL SHAFT
Most common long bone fracture. Slowest healing bone in body 10wk.
TILLAUX
Salter Harris 3 through anterolateral distal tibial epiphysis. Needs open physis in lateral distal tibia. Seen in window between start of medial physis fusion and complete fusion of lateral physis. Growth plate closes medial to lateral with lateral closing around 12-15yo.
TRIPLANE
Salter Harris 4 with vertical component through epiphysis, horizontal through physis then oblique through metaphysis. (oblique component distinguishes this from Tillaux)
MAISONNEUVE
Unstable fracture involving medial tibial malleolus and disruption of distal tibiofibular syndemosis. Widened ankle mortice then up through syndesmosis with proximal fibular fracture.
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A few foot fractures
CASANOVA
Bilat calcaneal fractures then look for T12-L2 burst fracture. Axial loading patterns. Peroneal tendons can get entrapped in calcaneal fractures. Calcaneal are most common tarsal fracture. Either extra or intra-articular depending on subtalar joint involvement.
Bohlers angle is line drawn between ant and post borders of calcaneus on lateral, <20 degrees concerning for fracture.
Critical angle of Gissane is on lateral aswell down anterior process then up at middle facet part normal 95-105
STRESS 5TH METATARSAL
High risk fracture hard to heal. Base of 5th MT shaft distal to intertarsal joint
JONES
Base of 5th MT into intertarsal joint
AVULSION BASE 5TH
More common than Jones. Tug from lateral cord plantar aponeurosis of peroneus brevis.
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Painful Os Peroneus syndrome POPS
Os peroneus is accessory ossicle within peroneus longus. 10% gen pop. Stress reaction and pain can progress to tendon disruption - POPS. Oedema in os peroneus just before peroneus longus tendon enters cuboid tunnel
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Lis Franc
Most common dislocation of foot. Articulation of tarsals and MT bases. Joint is recessed creating keystone locking mechanism. Lis Franc connects medial cuneiform to 2nd MT base on plantar aspect
Cant exclude on non weight bearing. Can get fracture non union and post traumatic arthritis if missed. Fleck sign is fleck of bone near base of 2nd MT which is avulsion of LF ligament.
Homolateral is all bones going lateral. Divergent is first MT going medial, remainder lateral.
Mechanism is extreme plantar flexion and axial loading. 3 ligaments make u complex between medial cuneiform and 2nd MT, plantar band is strongest.
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Anatomy trivia
Achilles tendn is largest in body. Fused gastroc and soleus. Does not have a tendon sheath so cant get tenosynovitis. Inflamm change around it is called paratendinitis.
MASTER KNOT OF HENRY
Where FD crosses over FHL at medial ankle. FHL starts out lateral, crosses over FDL to go medial to the great toe.
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Posterior tibial tendon injury/dysfunction
Progressive flat foot deformity as PTT is primary stabilizer of longitudinal arch. When chronic, tear usually behind medial malleolus (most friction here). When acute,tear most commonly at insertion into navicular. Acute flat arch should think PTT tear.
Also get hindfoot valgus from unopposed peroneus brevis action. Spring ligament is secondary supporter of longitudinal arch (holds up talar head) so this will then thicken and degenerate if no help from PTT
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Sinus tarsi syndrome
Important source of proprioception and balance. Syndrome caused by haemorrhage and inflammation of synovial recess with or without tears of associated ligaments (talocalcaneal ligaments, inferior extensor retinaculum). associations with rheumatological disorders and abnormal loading. MRI finding is obliteration of fat in sunus tarsi space and replacement with scar.
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Plantar fasciitis
Inflammation of fascia secondary to either repetitive trauma, abnormal mechanics (pes cavus) or arthritis (Reiters etc). Pain localised to origin of plantar fascia and worsened by dorsiflexion of toes.
Pantar fascia consists of 3 bands, central/lateral part thicker than the medial part.
Plain film heel spurs. Bone scan increased tracer in region of calcaneus. MRI thickened fascia >4mm usually central band with increased T2 signal near insertion at heel.
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Flat foot progression
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PTT tendon goes.
Spring ligament goes.
Sinus Tarsi damaged (including proprioception nerves)
Altered gait
Plantar fasciitis.
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Split peroneus brevis
Longitudinal split in peroneus in people with inversion injuries. History chronic ankle pain. Tendon C shaped or boomerang shaped with central thinning and partial envelopment of peroneus longus. Tear occurs at lateral malleolus. 80% association with lateral ligament injury.
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Anterolateral impingement syndrome
Injury to ATFL and tibifibular ligaments. from inversion injury can cause lateral instability and chronic synovial inflammation.
Eventual mass of hypertrophic synovial tissue in lateral gutter. MRI finding is meniscoid mass in lateral gutter of ankle which is balled up scar T1 and T2 dark
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Tarsal tunnel syndrome
Pain in distribution of pos tib nerve (first 3 toes) from compression as it passes through tarsal tunnel behind medial malleolus. Usually unilateral and idiopathic although pes planus can predispose by tightening retinaculum. Any mass lesion can compress it in tunnel (ganglion, varicosities, lipoma, tenosynovitis, accessory muscles).
Tarsal tunnel covered by flexor retinaculum and inculdes Tom Dick Harry an post tib artery and nerve
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Mortons Neuroma
Soft tissue mass, tear drop shaped between 3rd and 4th MT heads. Compression/entrapment of plantar digital nerve by intermetatarsal ligament. Over time results in thickening and development of perineural fibrosis.
Mortons neuroma is not a neuroma its a scar. Dark T1/T2. and project downward. Differential is intermetatarsal bursitis which extends above transverse ligament, fluid signal, cystic look
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Haglunds deformity/syndrome
Also called Mullholland deformity.
Retroachilles burstis/retrocalcaneal bursitis
Thicekning of distal achilles tendon
Calcaneal bony prominence posteriorly.
Deformity is the bump. Syndrome is the bursitis and achilles tendon thickening. High heels are predisposing
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Os trigonum syndrome
Os trigonum impedes FHL on extreme flexion or other microtrauma.
Classic findings stenosisn tenosynovitis/collection of fluid around FHL and oedema within os trgionum and accross synchondrosis between Os and posterior talus.
Synchondrosis is a joint that has essentially no movement and is lined with cartilage.
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Achilles tendon injury
Rupture usually obvious with fluid filled hap. Gap size determines treatment. Tear usually 4cm above calcaneal insertion. History weekend warrior with acute pain and unable to plantarflex.
With no gap hard to tell from xanthoma (look like thick tendon).
ACHILLES
Thick >7mm. Unilateral. Weekend warrior athlete.
XANTHOMA
Thick >7mm. Bilateral. High cholesterol association.
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Plantaris rupture
Tennis leg. "achilles tendon rupture but can still plantarflex. Absent 10% population. Classic look on MRI is focal fluid collection between soleus and medial head of gastroc. Association with ACL tear.
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Calcaneal avulsion
Back of bone completely ripped off via achilles. Classic association diabetes.
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Avulsion patterns
PLANTAR FASCIA
Avulsion of medial plantar process often associated with plantar spur.
EXTENSORY DIGITORUM BREVIS AVULSION
Fragment of bone arising at dorsolateral anterior calcaneus
CALCANEOCUBOID LIGAMENT AVULSION
Small linear bone fragment located lateral to calcanocuboid joint
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Low bone density
OSTEOPENIA
Increased lucency of bones.
OSTEOMALACIA
Soft bone from excessive uncalcified osteoid. Usually related to Vit D issues. Looks like diffuse ostepenia. Think: ill defined trabeculae, ill defined corticomedullary junction, bowing and Looser zones
Looser zones: wide lucent bands that traverse at right angles to cortex. Femoral neck and pubic rami classic. Sclerosis surrounding lucency. Should think Osteomalacia and Rickets, less common OI. Type of insufficiency fracture
OSTEOPOROSIS
Low bone density. Peaks at 30 then decreases. Decreases faster in women during menopause. Sharp cortex, prominent trabecular bars, lucent metaphyseal bands and spotty lucencies. Causes are: age,medications, endocrine issues (cushings, hyperthyroid), anorexia and OI. Complications are fractures
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DEXA
Bone mineral density test.
T score = density relative to young adult
T score defines osteopenia vs osteoporosis
T score > -1 normal, -1 to -2.5 osteopenia,
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FRAX
Fracture assessment tool. Predict fractures by using clinical risk factors (age, sex, race, BMI, FHx, personal fracture history, steroid use). Calculated as 10 year probability
Calculates 10 year fracture risk. Adds value by identifying those who are at higher risk and may benefit from pharmacological intervention. Applicable to men and women. Some guidelines suggest intervntion for those with FRAX hip fracture risk of >3% or major fracture risk of >20%
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Reflex sympathetic dystrophy RSD
aka Complex regional pain syndrome
aka Sudeck atrophy
History of trauma or infection. On plain film looks like severe osteopenia. Looks like unilateral RA with preserved joint spaces. Hand and shoulder most common sites. 3 phase hot bone scan. Intra-articular uptake of tracer on bone scan is typically seen in RSD due to vascularity of synovial membrane and is characteristic.
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Transient osteoporosis
TRANSIENT OSTEOPOROSIS OF HIP
Female 3rd trimester, left hip common. Self limiting. Joint space normal. Plain film osteopenia, MRI oedema, bone scan focal uptake.
REGIONAL MIGRATORY OSTEOPOROSIS
Idiopathic disorder, pain in joint which gets better and show up in another joint. Self limiting more common in men
RADIOGRAPH
Osteoporosis super lucent, AVN patchy sclerosis
MRI
Dark T1, oedema on STIR. AVN will have geographic serpigenous dark line representing infarct core. Joint effusions in both
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Compression fracture
OSTEOPOROTIC
Band like fracture line T1 dark.
NEOPLASTIC
Abnormal marrow signal with involvement of posterior margin. Normal vertebral body marrow in adult is fatty s T1 bright. If dark (darker than adjacenet normal disc) that is bad. Also look for lesions in adjacent vertebral bodies.
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Osteochondritis dissecans
Most common male <18. Most common lateral aspect of medial femoral condyle.
Aseptic separation of osteochondral fragment which can elad to gradual fragmentation of articular surfaceand secondary OA. Usually secondary to trauma., but can be secondary to AVN.
Femoral condyle, patella, talus and capitellum.
Look for high T2 signal undercutting fragment of bone to call unstable
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Capitellum lesions
OCD
Capitellum of dominant arm in throwers. Anterior convex margin of capitellum. Unstable if high signal fluid encircling osteochondral fragment on T2. Lead to intra-articular loose bodies. 12-16yo
PANNERS
Capitellum of throwers. Entire capitellum abnormal signal, low T1, high T2. Loos bodies NOT seen. 5-10yo
PSEUDO LESIONS
Posterior capitellum on coronal. Abrupt slope can mimic lesion but is normal.
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Osteochondroses
Collapse/sclerosis/fragmentation
KOHLERS
Navicular. 4-6yo male. Non surgical. Flat navicular
FREIBERG INFRACTION
Second metatarsal head flattened, adolescent girls. Lead to secondary OA.
SEVERS
Calcaneal apophysis. Normal "growing pain".
PANNERS
Capitellum. Kids 5-10yo, throwers, no loose bodies.
PERTHES
Femoral head. WHite kid 4-8yo.
KIENBOCK
Lunate adults 20-40yo, Negative ulnar variance.
SCHEURMANN
Thoracic spine. Kyphosis, 3 adjacent levels with wedging plus thoracickyphosis >40 degrees.
OSGOOD SCHLATTER
Tibial tubercle. Adolescents 10-15yo who jump and kick. Fragmentation and soft tissue swelling
SINDING LARSEN JOHANSSON
Inferior patella. Adolescents 10-15yo who jump
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Osteomyelitis
Radiographs normal 7-10 days. Can happen anywhere/any age. CHildren usually haematogenous spread, adults normally direct spread. Destruction of bone and periosteal new bone formation.
SEQUESTRUM
Piece of necrotic bone surrounded by granulation tissue
INVOLUCRUM
Thick sheath of periosteal bone around sequestrum
CLOACA
Defect in periosteum caused by infection
SINUS TRACT
Channel from bone to skin lined by granulation tissue
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Osteomyelitis
CHRONIC
Lasting longer than 6 weeks. Draining sinus tracts risk for squamous cell cancer. Most specific sign is presence of sequestrum. Healed osteomyelitis is when there is normal marrow signal.
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ACUTE BACTERIAL
Haematogenous seeding (child), contiguous spread or direct inoculation of bone from surgery or trauma.
Haematogenous usually long bones at metaphysis which has best blood flow and allows spreading into subperiosteal space.
Age <1 month vessels through growth plate, often involves joint. Age <18 months spread to epiphysis through blood. Age 2-16 physis is closed, primary focus is metaphyseal
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"ghost sign" is a bone which has poor definitions on T1 then reappears on T2 or after giving contrast. More likely to have osteomyelitis.
