MSK 3 Flashcards
End stage SLAC
In end stage SLAC, the midcarpal joint collapses under compression and the lunate assumes an extended or dursiflexed position - DISI
synovial thickening
ddx
- synovial thickening
- lipoma aborescence
- PVNS
- rheumatoid
*
dDx of ABC
Gorham disease
Dr Francis Deng and Dr Yuranga Weerakkody◉ et al.
Gorham disease or vanishing bone disease is a poorly understood rare skeletal condition which manifests with massive progressive osteolysis along with a proliferation of thin walled vascular channels. The disease starts in one bone but may spread to involve adjacent bony and soft tissue structures.
Terminology
Other names for this condition include progressive massive osteolysis, Gorham-Stout disease, and phantom bone disease.
Epidemiology
Gorham disease is thought to be non-hereditary and there is no recognised gender predilection. It can potentially occur in any age group although most reported cases have been in young adults 2.
Clinical presentation
Signs and symptoms are incredibly varied depending on the bones involved, and may only become apparent after a fracture.
Pathology
The osteolysis is thought to be due to an increased number of stimulated osteoclasts 3, which is likely secondary to abundant non-neoplastic vascular and lymphatic proliferation in the affected region 9. The bone is subsequently replaced by variable amounts of fibrous connective tissue that is hypervascular10.
Location
Gorham disease can potentially involve any bone. Reported sites include:
humerus (first reported case)
shoulder girdle
pelvis
skull 2
mandible
Splenic lesions (cysts) and soft-tissue involvement underlying skeletal disease represent characteristic extraskeletal manifestations supporting the diagnosis 6.
Radiographic features
Plain radiograph and CT
intramedullary or subcortical lucent foci may be the earliest manifestation 1
this progresses to profound osteolysis with resorption of affected bone and lack of compensatory osteoblastic activity or periosteal reaction
Scintigraphy
99mTc bone scan may initially be positive but later becomes negative with ongoing bone resorption
History and etymology
It was first reported by Jackson in 1838 12 and later defined by Gorham and Stout in 1955 13.
Differential diagnosis
Imaging differential considerations include:
generalised lymphatic anomaly
multifocal lymphatic malformations, including intramedullary bone lesions
does not classically cause progressive osteolysis 11
osteolytic metastases
osteolytic primary bone lesion
multiple myeloma
osteomyelitis
rapidly progressive osteoarthritis
Milwaukee shoulder
multicentric carpal tarsal osteolysis
Osteochondritis dissecans
Dr Mostafa El-Feky◉ and Assoc Prof Frank Gaillard◉◈ et al.
Osteochondritis dissecans (OCD) is the end result of the aseptic separation of an osteochondral fragment with the gradual fragmentation of the articular surface and results in an osteochondral defect. It is often associated with intraarticular loose bodies.
Epidemiology
Onset is between childhood and young adults age, with the majority of patients being between 10 and 40 years of age, with approximately a 2:1 male to female ratio 3.
Risk factors
repetitive throwing / valgus stress and gymnastics / weight bearing on upper extremity
valgus stress / compressive force on the vulnerable chondroepiphysis of the radiocapitellar joint in skeletally immature patients is supported as the aetiology for OCD of the capitellum 8
ankle sprain/instability
In the talus, 96% of lateral lesions and 62% of medial lesions were associated with direct trauma 9
competitive athletics 10
family history: epiphyseal dysplasia has been postulated as a subset of OCD 11
Clinical presentation
Symptoms are variable and range from asymptomatic to significant pain and locking (suggesting loose body formation). Joint effusions and synovitis are often present.
Pathology
The exact aetiology is uncertain and controversial, with the majority of cases thought to be the result of trauma 4. In up to 40% of cases, patients give a history of trauma as the inciting event 3. Other postulated causes include 4:
avascular necrosis (AVN)
fat emboli
microtrauma
familial dysplasia
Location
Many joints can be affected, but typical locations include:
femoral condyles are most common site accounting for ~95% of all cases: osteochondritis dissecans of the knee
talus: osteochondritis dissecans of the ankle
capitellum: osteochondritis dissecans of the elbow
glenoid 7
Staging
See osteochondral injury staging and osteochondritis dissecans surgical staging.
Radiographic features
Plain radiograph
Plain radiographs should be the first step in the evaluation of knee pain, however, unless advanced changes are present and/or a meticulous technique employed, early findings of osteochondritis dissecans may be occult. The intercondylar “notch” view is very helpful.
Early findings include subtle flattening or indistinct radiolucency about the cortical surface. As the process progresses, more pronounced contour abnormalities, fragmentation and density changes (both lucency and sclerosis) become evident. If an osteochondral fragment becomes unstable and displaced, then donor site and intra-articular fragment may be seen.
CT
CT has the advantage of sectional imaging through the joint and multiplanar reformats. Findings are similar to those seen on plain radiographs.
MRI
MRI is the modality of choice, with high sensitivity (92%) and specificity (90%) 4 in the detection of separation of the osteochondral fragment. This is essential in determining management.
T1:
variable signal overall with intermediate to low signal adjacent to fragment and variable fragment signal
T2:
the high signal line demarcating fragment from bone usually indicates an unstable lesion however false positives can result from oedema 6
low signal loose bodies, outlined by high signal fluid
donor defect filled with high signal fluid
high signal subchondral cysts
T1+gad:
enhancement indicates the viability of the lesion
The four classic signs of instability described at MRI include 14 :
high signal intensity rim at the interface between the fragment and the adjacent bone on T2-weighted MR image
fluid-filled cysts beneath the lesion
high signal intensity line extending through the articular cartilage overlying the lesion
focal osteochondral defect filled with joint fluid, indicating complete detachment of the fragment
Complications
persistent pain with activity: ~ 2/3 following surgical management of knee and 40% following surgical management of elbow 12,13
articular incongruity 13
early degenerative joint disease 13
Treatment and prognosis
Spontaneous healing is usual unless there is an unstable fragment, and treatment revolves around rest and immobilisation for up to a year 5.
When the fragment is unstable or displaced, without treatment patients are susceptible to premature secondary osteoarthritis. Numerous surgical approaches have been tried, including drilling, bone grafting, replacement of bone fragment and pinning 5.
When surgery is performed, the results in most cases are only “fair”. ~50% (range 35-70%) of patients achieve a “good to excellent” clinical outcome 3 but even in these cases, the majority develop osteoarthritis.
History and etymology
It was first described by the German surgeon Franz Konig in 1888.
Differential diagnosis
normal irregular distal femoral epiphyseal ossification
avascular necrosis
osteochondral impaction fracture
stress/insufficiency fracture
See also
differential diagnosis of erosive arthritis
Unicameral bone cyst
Dr Henry Knipe◉◈ and Assoc Prof Frank Gaillard◉◈ et al.
Unicameral bone cysts (UBC), also known as simple bone cysts, are common benign non-neoplastic lucent bony lesions that are seen mainly in childhood and typically remain asymptomatic. They account for the S (simple bone cyst) in FEGNOMASHIC, the commonly used mnemonic for lytic bone lesions.
Epidemiology
They are usually found in children in the 1st and 2nd decades (65% in teenagers) and are more common in males (M:F ~ 2-3:1) 2,6.
Clinical presentation
These lesions are usually asymptomatic and found incidentally, although pain, swelling and stiffness of the adjacent joint also occur. The most frequent complication is a pathological fracture, and this is frequently the cause of presentation 1,2,6.
Pathology
When uncomplicated by fracture the cysts contain clear serosanguineous fluid surrounded by a fibrous membranous lining. It is thought to arise as a defect during bone growth which fills with fluid, resulting in expansion and thinning of the overlying bone.
During the active phase, the cyst remains adjacent to the growth plate. As the lesion becomes inactive it migrates away from the growth plate (normal bone is formed between it and the growth plate) and it gradually resolves 3,5.
Location
They are typically intramedullary and are most frequently found in the metaphysis of long bones, abutting the growth plate 1. Locations include 1,2,5:
proximal humerus: most common 50-60%
proximal femur: 30%
other long bones
occurrence elsewhere is relatively uncommon, and usually occurs in adults
spine: usually posterior elements
pelvis: only 2% of UBC 1
UBCs can be rarely seen in adults in unusual locations such as in the talus, calcaneus, or the iliac wing.
Radiographic features
Plain radiograph
UBCs are well defined geographic lucent lesions with a narrow zone of transition, mostly seen in skeletally immature patients, which are centrally located and show a sclerotic margin in the majority of cases with no periosteal reaction or soft tissue component. They sometimes expand the bone with thinning of the endosteum without any breach of the cortex unless there is a pathologic fracture. Prominent ridges of bone can appear as pseudotrabeculation on x-ray but in fact, UBC is made of one contiguous cystic space. Rarely, they are truly multiloculated 3.
If there is fracture through this lesion a dependant bony fragment may be seen, and this is known as the fallen fragment sign.
CT and MRI
CT and MRI add little to the diagnosis, however, can be helpful in eliminating other entities that can potentially mimic a simple bone cyst (see differential diagnosis below).
MR signal characteristics for an uncomplicated lesion include:
T1: low signal
T2: high signal
Usually there no fluid-fluid levels unless there has been a complication with haemorrhage.
Scintigraphy
Unicameral bone cyst on bone scintigraphy tends to appear as foci of photopenia (cold spot). However, a pathological fracture would cause an increased radioisotope activity.
Treatment and prognosis
Intervention is usually not required for an asymptomatic lesion. If large and threatening to fracture, or causing deformity then an intralesional steroid injection can be performed 3-5. If fractured the bone usually heals normally 5. In some instances, surgery with curettage and bone grafting is required.
Differential diagnosis
General imaging differential considerations include
intraosseous lipoma
fibrous dysplasia
eosinophilic granuloma (EG)
giant cell tumour of bone: usually older, extending to articular surface
non ossifying fibroma: eccentric, cortical base
haemophilic pseudotumour (intraosseous)
aneurysmal bone cyst (ABC): usually eccentric
runners and cyclists
oedema between ITB and Lat fem condyle
Hx may be ? lat meniscus tear
this is the next cause for lat knee pain.
Iliotibial band syndrome
Dr Yuranga Weerakkody◉ and Dr Saqba Farooq et al.
Iliotibial band (friction) syndrome is a common cause of lateral knee pain related to intense physical activity resulting in chronic inflammation. Alternatively, the same pathology can occur over the greater trochanter and is considered the same diagnosis.
Epidemiology
Commonly affect young patients who are physically active, most often long-distance runners or cyclists. The exact prevalence is unknown, but one study has found the prevalence among actively training marines to be higher than 20% 5. Iliotibial band syndrome accounts for 12% of running-related overuse injuries 4.
Clinical presentation
Classically, iliotibial band syndrome is diagnosed by history and physical examination. Pain over the greater trochanter or at the lateral knee joint is the presenting symptom with point tenderness 1-2 cm above the lateral joint line. Pain is usually worse with downhill running and increases throughout an episode of activity 4.
Pathology
When the knee flexes, the iliotibial band (ITB) moves posteriorly over the lateral femoral epicondyle. When the band is excessively tight or stressed, the ITB rubs against the epicondyle irritating the lateral synovial recess.
WIth hip flexion, the ITB slides anteriorly over the greater trochanter and may cause a painful clunking sensation or audible snap.
Aetiology
The following physical factors are reported to be associated with the development of the syndrome 4:
limb length discrepancy
genu varum
overpronation
hip adductor weakness
myofascial restriction
Microscopic appearance
The histologic analysis demonstrates inflammation and hyperplasia in the synovium.
Radiographic features
Ultrasound
Allows visualisation of the impingement by assessing dynamic motion of the ITB through knee flexion and extension.
MRI
MRI is reserved for when the diagnosis is unclear and to exclude other aetiologies of lateral knee pain such as a meniscal tear or lateral collateral ligament injury.
MR findings of ITB syndrome include ill-defined signal abnormality within the fatty soft tissues interposed between the ITB and bone. In the knee, the soft tissues lateral to the lateral femoral condyle show low T1 and high on T2 signal, in keeping with oedema/fluid. In the hip, similar soft tissue changes are present and there may also be tendinopathy or tear of the gluteus medius or minimus tendons. There may also be marrow oedema in the affected bone.
Cystic areas representing primary or secondary (adventitious) bursae may be identified.
Chronic MR findings include thickening of the ITB and increased T2 signal intensity superficial to the ITB are occasionally seen. Soft tissue fibrosis and bony proliferation may be present.
Treatment and prognosis
Initial treatment is conservative, consisting of physical therapy, anti-inflammatory medication, and steroid injections 3.
Surgical treatment is reserved only for those who fail conservative treatment and includes resection of the posterior aspect of the ITB 3.
Differential diagnosis
General imaging differential considerations include:
lateral meniscal tear
lateral collateral ligament injury
See also
proximal iliotibial band syndrome
Fibrous Dysplasia
Polyostotic
- Basion Dens Interval discociaterval
- Kids < 8 year have different injury pattern and have high risk of ligamentous injury
- Kids < 8 years have an adult injury pattern.
- don’t miss bilateral injury.
- Used to evaluate Atlanto-occipital discociation injuries.
- Distance from the basion to the tip of the dens should be < 12mm on x-ray or <8.5mm on Ct.
What are the main differences in characteristics of Primary bone tumours VS primary Soft tissue tumours (that are near bone).
- Primary Bone tumours
- Epicentre centered on bone.
- Beveling away from bone (ie inside to out)
- Periosteal Reaction present
- Large boney component, small soft tissue component.
- Primary Soft tissue Tumours
- Epicentre in soft tissues adjacent to bone
- Bevelling towards bone (ie Outside in)
- Periosteal reaction absent
- Large soft tissue component, small boney component.
Describe the FiCAT Classification
2019 Aug Q100
Ficat and Arlet classification of avascular necrosis of femoral head
Dr Mostafa El-Feky◉ and Assoc Prof Frank Gaillard◉◈ et al.
The Ficat and Arlet classification uses a combination of plain radiographs, MRI, and clinical features to stage avascular necrosis of the femoral head.
Classification
stage 0
plain radiograph: normal
MRI: normal
clinical symptoms: nil
stage I
plain radiograph: normal or minor osteopenia
MRI: oedema
bone scan: increased uptake
clinical symptoms: pain typically in the groin
stage II
plain radiograph: mixed osteopenia and/or sclerosis and/or subchondral cysts, without any subchondral lucency (crescent sign: see below)
MRI: geographic defect
bone scan: increased uptake
clinical symptoms: pain and stiffness
stage III
plain radiograph: crescent sign and eventual cortical collapse
MRI: same as plain radiograph
clinical symptoms: pain and stiffness +/- radiation to knee and limp
stage IV
plain radiograph: end-stage with evidence of secondary degenerative change
MRI: same as plain radiograph
clinical symptoms: pain and limp
History and etymology
The French orthopaedic surgeon Paul (RP) Ficat (1917-1986) 4 in association with Professor Jacques Arlet devised a system of staging idiopathic avascular necrosis of femoral head in the late 1970s based on two fundamental concepts 2:
a standard radiograph shows only the shadow of the mineralised portion of a bone
bone necrosis is the end result of severe and prolonged ischaemia
See also
avascular necrosis
avascular necrosis of the hip
Steinberg staging
ARCO classification
Segond fracture
Avulsion of middle third of lateral capsular ligs
VERY HIGH ASSCOIATION WITH ACL tears
Internal rotation and varus with internal rotation
look for posterolateral corner injuries
LCH
Osteopathia striata
AKA: Voorhoeve Disease
- Linear longitudinal striations in metaphyses
- A/W focal dermal hypoplasia (Goltz syndrome)
- “Celery Stalk metaphysis”
Meniscocapsular separation
Meniscocapsular separation
Meniscocapsular separation refers to detachment of the meniscus from its capsular attachments. It is an uncommon injury.
Clinical presentation
Clinical findings are nonspecific and can include pain, instability, and joint effusion.
Pathology
Location
it is more common in the medial (more frequently posterior horn region 5) than in the lateral compartment of the knee
ramp lesions are a specific type of meniscocapsular injury associated with ACL-deficient knees 6
meniscofemoral detachment is more common than meniscotibial detachment 4
Associations
While it can uncommonly occur in isolation, it is more often associated with other ligamentous injuries.
Radiographic features
MRI
Meniscocapsular separation is usually diagnosed arthroscopically and the positive predictive value (PPV) of MRI has been traditionally described as being low 3 (as low as 9% medially and 13% laterally).
Low predictive value MRI findings that have been correlated with meniscocapsular separation include 1-2:
interposition of fluid between the meniscus and the medial collateral ligament
meniscal corner tears: according to one study had a PPV of 0% medially and 50% laterally 3
perimeniscal fluid
meniscofemoral and meniscotibial extension tears
irregular meniscal outline
increased distance between the meniscus and the medial collateral ligament
visualisation of fluid from the superior all the way to the inferior end of the meniscus has been described as a more suggestive feature 5 (PPV unknown)
On MR arthrography meniscocapsular separations have been correlated with interposition of contrast medium between the meniscus and the medial collateral ligament.
Treatment and prognosis
It may heal after conservative treatment or after re-suturing the meniscus into the capsule.
Complications
Potential complications include:
increased meniscal mobility and resultant meniscal tears 5
Differential diagnosis
On MRI consider a normal menisco-synovial recess / perimeniscal recess 4.
SLAC Wrist
OA and CPPD and Rheumatoid
adamantimoma
anterior tibial cortex is typical
ddx is OM and FCD
dash board injury
forse is applied to an aspect of prox tib with flex knee
Puture PCL
Check PCL, POp art and nervers
Describing the epicenter of the lesion
Intra-articular
central
eccentric
cortical
paraosteal
Mazabraud syndrome + ABC
Erosive OA
- gull wing
- joint space narrowing
- central erosions
- PIP and DIP
- Ankylosis
- Undulating osseus contours
- F > M
- Subluxations on ulnar side
- does not effect MCP/intercarpals/proximal zones
- if you see it proximally, may be psoriasis
popliteaus pseudotear
mimics posterior tear
Volar plate avulsion injury
Dr Mohamed Saber and Dr Charlie Chia-Tsong Hsu et al.
Volar plate avulsion injuries are a type of avulsion injury. The volar plate of the proximal interphalangeal (PIP) joint is vulnerable to hyperextension injury, in the form of either a ligament tear or an intra-articular fracture.
Gross anatomy
The volar plate forms the floor of the PIP joint separating the joint space from the flexor tendon sheath. The volar plate has a ligamentous origin on the proximal phalanx with a capsular insertion onto the middle phalanx.
Pathology
Hyperextension injury involving the PIP of the finger can avulse the volar plate which is commonly associated with a volar avulsion fracture at the base of the middle phalanx.
When the volar avulsion fracture involves a significant portion of the articular surface, instability and dorsal dislocation of middle phalanx can occur. This is because a greater portion of the stabilizing collateral ligaments is attached to the avulsed fragment.
Classification
Knowledge of the orthopedic Eaton classification is practical when reporting volar plate injury as it influences the decision on management 3. Treatment is dependent on the following factors:
size of the fragment (<40% of articular segment)
degree of impaction
direction of the dislocation
Another classification which is considered useful for management is the Keifhaber-Stern classification.
Radiographic features
A small fragment of bone is avulsed from the volar base of the middle phalanx. If there is significant involvement of the articular surface, this may be associated with dorsal dislocation of the middle phalanx.
Treatment and prognosis
Overall, a small fragment involving <40% of the articular segment and/or reducible fracture with < 30 degrees of flexion is usually managed conservatively with finger splinting. A large fragment or > 30 degrees of flexion to reduce the fragment and malalignment post-closed reduction are indicators for operative treatment.
Giant Cell Tumour
Case courtesy of Radswiki, Radiopaedia.org, rID: 11454
Hoffas fat pad inpingement
- Hoffas fat pad inpingement
- cause of anterior knee pain
There is a well-circumscribed anterior paraarticular oval mass within the infrapatellar (Hoffa’s) fat pad. It appears isointense to the muscles on T1WI with a central area of high signal (isointense to the articular cartilage), heterogeneous high signal on PD fat sat sequences with a central area also isointense to the articular cartilage and peripheral hypointense rim (calcification). No enhancement is seen following IV contrast administration. Note mild oedema of high signal within of the infrapatellar fat pad with no lesion of the adjacent bone. An intraarticular effusion is noted. Grade 3 vertical oblique tear of the posterior horn of the medial meniscus.
Case Discussion
Intracapsular (osteo-)chondroma of the knee is a rare benign tumour of cartilaginous origin due to an extrasynovial metaplasia, usually located within the infrapatellar fat pad.
The main differential diagnoses include localised pigmented villonodular synovitis (also known as intraarticular giant cell tumour of the tendon sheath), calcified synovial sarcomas, calcifying bursitis, primary synovial chondromatosis, periosteal chondromas, and soft tissue chondrosarcoma.
Localised pigmented villonodular synovitis typically appears as a soft tissue mass of midline location within the infrapatellar fat pad in contact with the patellar tendon. Its signal intensity is variable; however, the presence of low signal intensity on all sequences is a typical feature, indicating haemosiderin deposition.
calvarlia haemangioma
Radiographic features
Five classic bone contusion patterns have been described 1-4:
pivot-shift injury
valgus stress to flexed and externally rotated knee
contusion pattern: posterolateral tibial plateau and mid part of lateral femoral condyle
associated with anterior cruciate ligament (ACL) tears
see also: contrecoup injury of the knee, O’Donoghue unhappy triad
Haemophilic arthropathy refers to permanent joint disease occurring in haemophilia sufferers as a long-term consequence of repeated haemarthrosis.
EpidemiologyCut
Around 50% of patients with haemophilia will develop a severe arthropathy.
Clinical presentation
Presents similarly to osteoarthritis, with chronic joint pain, reduced range of motion and function, and reduced quality of life.
Pathology
Haemophilia is an X-linked recessive disease affecting mainly males. Haemarthroses may be spontaneous or result from minor trauma and typically first occurs before the age of two and continues to occur into adolescence. It is usual for the same joint to be repeatedly involved. In adulthood, haemarthroses are uncommon. However, proliferative chronically-inflamed synovium results in the development of haemophilic arthropathy.
The haemarthroses results in the deposit of iron in the intraarticular region, which then leads to the proliferation of the synovium, neoangiogenesis, and ultimately damage to both the articular cartilage and subchondral bone 8.
Haemophilic arthropathy is characterised by synovial hyperplasia, chronic inflammation, fibrosis, and haemosiderosis. The synovium mass erodes cartilage and subchondral bone leading to subarticular cyst formation 3.
Location
Haemophilic arthropathy is often monoarticular or oligoarticular. Large joints are most commonly involved in the following order of frequency 2:
knee
elbow
ankle
hip
shoulder
Radiographic features
Plain radiograph
joint effusion is seen in the setting of haemarthrosis
periarticular osteoporosis: from hyperaemia
epiphyseal enlargement with associated gracile diaphysis: from hyperaemia (appearances can be similar to juvenile rheumatoid arthritis and paralysis)
secondary degenerative disease: symmetrical loss of joint cartilage involving all compartments equally with periarticular erosions and subchondral cysts, osteophytes and sclerosis
knee 3
widened intercondylar notch
squared inferior margin of the patella
bulbous femoral condyles
flattened condylar surfaces
changes can be classified through the Arnold-Hilgartner classification 4
elbow 2
enlarged radial head
widened trochlear notch
ankle 1
talar tilt: relative undergrowth of the lateral side of the tibial epiphysis leads to a pronated foot
LCL
ant post - ITB, LCL, biceps fem
ITB inserts on gerdys tubercle
significance of ulnar variance.
Associations
positive ulnar variance is associated with ulnar impaction syndrome.
negative ulnar variance is associated with Kienbock disease and ulnar impingement syndrome
Ulnar variance (also known as Hulten variance) refers to the relative lengths of the distal articular surfaces of the radius and ulna.
Ulnar variance may be:
neutral (both the ulnar and radial articular surfaces at the same level)
positive (ulna projects more distally)
negative (ulna projects more proximally)
Variance is independent of the length of the ulnar styloid process.
Pathology
Aetiology
trauma or mechanical
distal radius/ulnar fractures with shortening (e.g. impaction) and angulation
DRUJ ligamentous injuries (e.g. Galeazzi and Essex-Lopresti-fracture dislocations)
surgical shortening of ulna or radius
growth arrest (e.g. previous Salter-Harris fracture)
congenital
Madelung deformity/reverse Madelung deformity
Radiographic assessment
Ulnar variance changes with wrist position (more positive with maximum forearm pronation and negative with maximum forearm supination) and increases significantly during a firm grip 1.
To determine ulnar variance on radiographs, the generally accepted standard view is a posteroanterior view obtained with the wrist in neutral forearm rotation, the elbow flexed 90° and the shoulder abducted 90°.
Positive variance occurs when the level of the ulna is >2.5 mm beyond the radius margin at the distal radio-ulnar joint. Negative variance is when the ulna is ≤2.5 mm than the radius at the DRUJ 1.
what is this?
Rheumatoid arthritis (RA) is a chronic multi-system disease with predominant musculoskeletal manifestations. Being a disease that primarily attacks synovial tissues, RA affects synovial joints, tendons, and bursae.
Refer to the related articles for a general discussion of rheumatoid arthritis and for the particular discussion of its respiratory and/or cardiac manifestations.
Radiographic features
Regarding disease detection, as the early RA manifestations are non-osseous in nature, ultrasound and MRI have shown to be superior to radiographs and CT. Plain radiography, however, remains the mainstay of imaging in the diagnosis and follow-up of RA 2.
Plain radiograph
One large cohort study showed that radiographically demonstrable erosions were present in 30% of patients at diagnosis, and in 70% three years later 4.
The radiographic hallmarks of rheumatoid arthritis are:
erosions; important early finding, in the “bare areas”, frequently in the radial side of the metacarpophalangeal (MCP) joints 7
soft tissue swelling
fusiform and periarticular; it represents a combination of joint effusion, oedema and tenosynovitis 5
this can be an early/only radiographic finding
osteoporosis: initially juxta-articular, and later generalised; compounded by corticosteroid therapy and disuse
joint space narrowing: symmetrical or concentric
Hands and wrists
Diagnosis and follow-up of patients with RA commonly involve imaging of the hands and wrists. The disease tends to affect the proximal joints in a bilaterally symmetrical distribution.
RA is a synovial based process, with a predilection for:
PIP and MCP joints (especially 2nd and 3rd MCP)
ulnar styloid
triquetrum
As a rule, the DIP joints are spared.
Late changes include:
subchondral cyst formation: the destruction of cartilage presses synovial fluid into the bone
subluxation causing:
ulnar deviation of the MCP joints
boutonniere and swan neck deformities
hitchhiker’s thumb deformity
carpal instability: scapholunate dissociation, ulnar translocation
ankylosis
scallop sign: erosion of the ulnar aspect of the distal radius which may be predictive of extensor tendon rupture (Vaughan-Jackson syndrome)
pencil-in-cup deformity: classically psoriatic arthropathy but well-recognised in rheumatoid arthritis
Elbow
joint effusion (elevated fat pads)
joint space narrowing
periarticular erosions
cystic changes
Feet
similar to the hands, there is a predilection for the PIP and MTP joints (especially 4th and 5th MTP)
involvement of subtalar joint
posterior calcaneal tubercle erosion
hammertoe deformity
hallux valgus
Shoulder
erosion of the distal clavicle
marginal erosions of the humeral head: the superolateral aspect is a typical location 2
reduction in the acromiohumeral distance: “high-riding shoulder” due to subacromial-subdeltoid bursitis and high incidence of rotator cuff tear
Hip
concentric loss of joint space, compared with osteoarthritis (OA) where there is a tendency for superior loss of joint space
acetabular protrusion
Knee
joint effusion
typically involves the lateral or non-weight bearing portion of the joint
loss of joint space involving all three compartments
lack of subchondral sclerosis and osteophytes, compared with OA
prepatellar bursitis
Spine
The cervical spine is frequently involved in RA (in approximately 50% of patients), whereas thoracic and lumbar involvement is rare. Findings include:
erosion of the dens
atlantoaxial subluxation
atlantoaxial distance is more than 3 mm on a flexion radiograph
atlantoaxial impaction (cranial settling): cephalad migration of C2
erosion and fusion of uncovertebral (apophyseal joints ) and facet joints
osteoporosis and osteoporotic fractures
erosion of spinous processes
Tuberculosis (musculoskeletal manifestations)
Dr Daniel J Bell◉ and Dr Prashant Mudgal et al.
Musculoskeletal tuberculosis is always secondary to a primary lesion in the lung.
Epidemiology
The prevalence of the disease is around 30 million globally and 1-3% of the 30 million have involvement of their bones and/or joints. Mycobacterium tuberculosis is responsible for almost all of the cases of osteoarticular tuberculosis; although atypical mycobacteria have been reported in lesions of the synovial sheath.
The predisposing factors are protein-energy malnutrition, environmental conditions and living standards such as poor sanitation, overcrowded housing and slum dwelling. Trauma as a causative factor is debatable, but has been reported. Acquired immunodeficiency syndrome and other causes of immunocompromised status and repeated pregnancies and lactation in women are also a factor.
Pathology
Osteoarticular tuberculosis can occur in the spine, hip, knee, foot, elbow, wrist, hand, shoulder and as diaphysial foci. It has not been reported to affect the mandible or the temporomandibular joint. The major method of spread is haematogenous. The most common method of spread to the vertebral body is through the Batson prevertebral venous plexus.
Osteoarticular tuberculosis is reported in various sites including:
tuberculosis of the spine
tuberculous arthropathy
tuberculosis of the tendon sheath and bursae
tuberculous osteomyelitis
tuberculous dactylitis
case:
Patient Data
AGE: 11 years old
GENDER: Male
4 case questions available
X-RAY
Oblique
Lateral
X-ray
Oblique
Oblique view of both hand radiograph and lateral view of left elbow show soft tissue swelling and multiple cystic bony destructions involving all long tubular bones and carpal bones. Benign solid periosteal reaction along left humerus is partly visualised.
Case Discussion
The patient was known case of paediatric AIDS and diagnosed disseminated tuberculosis. He re-visited hospital with both wrist and left elbow swelling, multiple skin abscesses at left and, right axilla, and left elbow. The AFB staining from the abscesses were positive1+ at right hand, 3+ at right axilla and 1+ at left elbow. The left epitrochlear nodes are enlarged and positive AFB staining 1+.
The plain radiograph of both hands and left elbow show multiple cystic osteolytic lesions involving all long tubular bones and carpal bones. This case demonstrates “osteitis tuberculosa multiplex cystoides” or “Jungling disease” which is the multifocal musculoskeletal TB and often found in disseminated disease and conjoined with pulmonary infection. The differential diagnoses are categorised in infection (e.g. disseminated pyogenic osteomyelitis) and neoplasms (e.g. eosinophilic granuloma or small round cell tumours).
Oblique view of both hand radiograph and lateral view of left elbow show soft tissue swelling and multiple cystic bony destructions involving all long tubular bones and carpal bones. Benign solid periosteal reaction along left humerus is partly visualised.
Case Discussion
The patient was known case of paediatric AIDS and diagnosed disseminated tuberculosis. He re-visited hospital with both wrist and left elbow swelling, multiple skin abscesses at left and, right axilla, and left elbow. The AFB staining from the abscesses were positive1+ at right hand, 3+ at right axilla and 1+ at left elbow. The left epitrochlear nodes are enlarged and positive AFB staining 1+.
The plain radiograph of both hands and left elbow show multiple cystic osteolytic lesions involving all long tubular bones and carpal bones. This case demonstrates “osteitis tuberculosa multiplex cystoides” or “Jungling disease” which is the multifocal musculoskeletal TB and often found in disseminated disease and conjoined with pulmonary infection. The differential diagnoses are categorised in infection (e.g. disseminated pyogenic osteomyelitis) and neoplasms (e.g. eosinophilic granuloma or small round cell tumours).
Tuberculous spondylitis
Dr Bahman Rasuli◉ and Dr Hani Makky Al Salam et al.
Tuberculous spondylitis, also known as Pott disease, refers to vertebral body osteomyelitis and intervertebral discitis from tuberculosis (TB). The spine is the most frequent location of musculoskeletal tuberculosis, and commonly related symptoms are back pain and lower limb weakness/paraplegia.
Epidemiology
Tuberculous spondylitis is one of the more common infections of spine in countries where TB is prevalent. Unfortunately, the incidence of tuberculous spondylitis, as with other forms of TB, is on the rise, due to new multiple drug resistant strains.
Discitis and/or osteomyelitis comprise approximately 50% of all musculoskeletal tuberculosis, and usually affects the lower thoracic and upper lumbar levels of the spine 2.
Clinical presentation
Patients usually present with back pain, lower limb weakness/paraplegia, and kyphotic deformity. Constitutional symptoms (fever and weight loss) are also common but not as pronounced as with bacterial discitis/osteomyelitis.
Pathology
The spine is involved due to hematogenous spread via the venous plexus of Batson 2. There is usually a slow collapse of one or usually more vertebral bodies, which spreads underneath the longitudinal ligaments. This results in an acute kyphotic or “gibbus” deformity. This angulation, coupled with epidural granulation tissue and bony fragments, can lead to cord compression. Unlike pyogenic infections, the discs can be preserved and it more commonly involves the thoracic spine. In late-stage spinal TB, large paraspinal abscesses without severe pain or frank pus are common, leading to the expression “cold abscess”.
Radiographic features
Plain radiograph
The spread of infection is typically described as ‘sub-ligamentous’: beneath the anterior longitudinal ligament, usually sparing the posterior elements and often involving multiple levels.
Tuberculous spondylitis can be difficult to detect in early stages because of relative preservation of the disc space.
A reduction in vertebral height is often seen with the irregularity of the anterosuperior endplate being relatively early and subtle sign. Due to the subligamentous extension, there may be some irregularity of the anterior vertebral margin. This is a classical appearance with TB spondylitis.
Later, paraspinal collections can develop which can be remarkably large.
Ivory vertebrae can result in re-ossification. Other associated features may include:
gibbus deformity
vertebra plana
As with other extrapulmonary TB, the chest film may be unrevealing (no pulmonary lesions seen in up to 50% of cases), with the source being a primary lung lesion that is clinically silent.
CT and MRI
Cross-sectional imaging is required to assess better the extent of involvement and particularly for the presence of an epidural component and cord compression. MRI is the modality of choice for this, with CT with contrast being a distant second.
Features include irregularity of both the endplate and anterior aspect of the vertebral bodies, with bone marrow oedema and enhancement seen on MRI:
T1: hypointense marrow in adjacent vertebrae
T2: hyperintense marrow, disc, soft tissue infection
T1 C+ (Gd): marrow, subligamentous, discal, dural enhancement
The paraspinal collections are typically well circumscribed, with fluid centres and well-defined enhancing margins 7.
Differential diagnosis
In many parts of the developing world, TB is the most common cause of vertebral body infection, with the majority of cases seen in patients under the age of 20. TB can also affect the meninges of the spine, causing an intense pachymeningitis that enhances dramatically.
brucellosis: can present as granulomatous osteomyelitis of the spine that can be difficult to distinguish from TB. Both are acid-fast bacilli, which may cause caseating granuloma(s)
fungal infection
sarcoidosis
pyogenic infection
compared to pyogenic infection tuberculous spondylitis has relatively preserved disk-space height, forms large paraspinal abscesses with a smooth enhancing wall and there is usually systemic involvement of multiple organs
see: tuberculous spondylitis versus pyogenic spondylitis
metastasis
Robins Mycobacterial Osteomyelitis (p. 1196)
Tuberculous osteomyelitis occurs in 1% to 3% of patients with tuberculosis; organisms are typically bloodborne, although direct extension or lymphatic seeding can occur. The spine is involved in 40% of cases (Pott disease) with frequent invasion into soft tissues and abscess formation. Lesions exhibit typical granulomatous reaction with caseous necrosis.
Avascular necrosis of the hip
Dr Yuranga Weerakkody◉ and Assoc Prof Frank Gaillard◉◈ et al.
Avascular necrosis of the hip is more common than other sites, presumably due to a combination of precarious blood supply and high loading when standing.
Clinical presentation
The most common presenting symptom is a pain in the region of affected hip, thigh, groin, and buttock. Although few patients may remain asymptomatic until late stages.
Pathology
Typically it affects the superior articular surface (between 10-2 o’clock) and begins in the most anterior part of the hip.
Aetiology
It can be thought of as traumatic (secondary to the neck of femur fractures) or non-traumatic. In non-traumatic cases, it is bilateral in 40%.
traumatic
chronic corticosteroid therapy
alcoholism
smoking
systemic lupus erythematosus (SLE)
hyperlipidaemias
HIV
haemoglobinopathies
chronic renal failure
diabetes mellitus
pregnancy-related
Radiographic features
Specific staging system (Ficat staging) exists for the hip which includes x-ray, MRI and bone scan appearances, and covers much of the imaging appearances, thus please refer to that article.
Other than describing the general appearance of the affected region, the following are necessary to include in the report as they have a bearing on prognosis and treatment:
position
estimating percentage volume of the head involved (axial) and percentage weight-bearing surface involved (coronal)
coexisting osteoarthritis or secondary degenerative change
joint effusion
presence of a potentially unstable osteochondral fragment: rim sign
subchondral fractures
CT
Often more sensitive than plain film in showing subchondral fractures.
MRI
MRI is the most sensitive modality, with a sensitivity of 71-100% and specificity of 94-100%1. As there is a high rate of bilateral involvement, both hips should be included in the field of view of at least some sequences.
T1: usually the initial specific findings are areas of low signal representing oedema, which can be bordered by a hyperintense line which represents blood products
T2: may show a second hyperintense inner line between normal marrow and ischaemic marrow. This appearance is highly specific for AVN hip and known as “double line sign”.
The Mitchell classification is commonly used to classify AVN based on MR-images.
Differential diagnosis
In some situations consider
subchondral insufficiency fracture of the femoral head - considered by some as a different entity 9
General imaging differential considerations include:
haematopoietic marrow (see bone marrow)
Pitt’s pit
fovea centralis
idiopathic transient osteoporosis of the hip (ITOH)
hyperaemia with diffuse increased uptake of radiotracer by the femoral head, neck, and intertrochanteric region
chondroblastoma
fracture
infection
pain and fever
usually involves both sides of the joint
metastases
Cortical lesions
(most commonly benign)
causes of AVN
mnemonic: GIVE INFARCTS
Gaucher disease
Idiopathic (Legg-Calve-Perthes, Kohler, Chandler)
Vasculitis (SLE, polyarteritis nodosa, rheumatoid arthritis)
Environmental (frostbite, thermal injury)
Irradiation
Neoplasia (-associated coagulopathy)
Fat (prolonged corticosteroid use increases marrow)
Alcoholism
Renal failure + dialysis
Caisson disease
Trauma (femoral neck fracture, hip dislocation)
Sickle cell disease
Location: femoral head (most common), humeral head,
femoral condyles
Bennett’s Fracture
Bennet #:
- Dorsal tradial dislocation
- force from abductor pollicis langus
- a small fragment maintains articulations w trapezium
Rolando #:
- Comminuted BENNETT #
- Fracture line may have “Y”, “V” or “T” configuration
- Decompression sickness
- Dr Daniel J Bell◉ and Dr M Venkatesh et al.
- Decompression sickness (DCS), also known as diver’s disease, aerobullosis, the bends or caisson disease, is an uncommon diving-related decompression illness that is an acute neurological emergency typically occurring in deep sea divers.
- Clinical Presentation
- Decompression sickness can be further clinically subdivided into:
- mild symptoms: arthralgia, skin marbling, small patchy haemorrhages, and lymphatic obstruction
- serious and life-threatening symptoms: affecting the brain, spinal cord, inner ear, and/or lung
- Pathology
- Nitrogen gas bubbles can cause neurovascular infarction of the brain and spinal cord leading to neurological deficit. There are various theories to explain this, which hypothesise between arterial occlusion, venous infarction and cellular nitrogen toxicity.
- Location
- The white matter tracts of the spinal cord and brain are predominantly affected due to their high myelin content 3. Cord lesions are more common than brain lesions. In the spinal cord, there is a predilection for the thoracic cord segments to be affected, thought to be secondary to more nitrogen accumulating in the lateral and posterior columns where there is higher fat content and also the relatively low blood flow compared to the cervical and lumbar segments.
- Complications
- bone infarction
- spinal cord infarct
- Radiographic features
- MRI
- Radiological changes are seen in early stages in MRI, but have very low specificity. The affected white matter may show ischaemic lesions or the bubbles themselves. There may also be an accumulation of nitrogen bubbles in marrow fat.
- Normal MRI of the cord does not rule out the diagnosis 3. If there are MRI findings, these tend to normalise after a few weeks.
- Treatment and prognosis
- hyperbaric oxygen on site and during transportation followed by treatment in a recompression chamber
- The quicker treatment begins, the higher the chance of successful recovery.
- History and etymology
- A caisson is a watertight container used in underwater construction work.
- The bends refers to the joint pain associated with the disease
https://www.semanticscholar.org/paper/A-study-of-old-lesions-of-caisson-disease-of-bone-Gregg-Walder/06dd820f98223d54ee36dcdf4c42bc4182fdc9b6
Post-traumatic digital ischemia from thrombosis of ulnar artery at Guyon’s canal.
Epidemiologyincidence
rare
demographics
male: female ratio is 9:1
age bracket is 40s-50s
location
unilateral, dominant ring finger +/- small finger
less commonly, index and middle fingers
thumb is spared
risk factors
occupations using vibrating tools such as carpenters, machinists, mechanics
sports such as baseball catchers, mountain biking, golf, volleyball, karate
Pathophysiologymechanism
single or repetitive blunt impact on hypothenar eminence leads to ulnar artery thrombosis or aneurysm
hook of hamate functions as an anvil, causing thrombosis
distal embolisation leads to ulceration, gangrene
Pes Ansuerinus Bursitis
Medial knee pain
Say Grace before T
Sartorius, Gracillus, Bicepts tendon
Plain Xray Approach to solitary bone lesion
- Lytic or Sclerotic
- Age <30 or >30
- Location in the body
- Location in the bone
- Periosteal Reaction
- Tumour Matrix
- Bone Destruction
- Margins
- Soft tissue component
- Pedunculated osteochondroma
- sessile osteochondroma
- enchondromas
- usually just lucent lesions
- but in other bones have a chondroid matrix
- Chondroblastoma
- epiphysis/growth plate tumour
- UBC
- fallen fragment
- ABC
- diaphyseal
- NOF
- cortically based lesion
- expansile
- healing NOF as it heals becomes sclerotic
Achilles tendinopathy
Dr Mohamed Saber and Dr Yuranga Weerakkody◉ et al.
Achilles tendinopathy refers to a combination of pathological changes affecting the Achilles tendon usually due to overuse and excessive chronic stress upon the tendon. It can be seen both in athletes and non-athletes. It is hard to differentiate clinically from a paratendinopathy (which is most common). It may or may not be associated with an Achilles tendon tear.
Epidemiology
It can affect a range of people from athletes to recreational exercisers and even inactive people. It affects non-athletes in around one-third of cases.
Pathology
Macroscopically, tendinopathy results in enlargement, disruption of fibrillar pattern and an increase in tendon vascularity. Histopathologically, there is evidence of disorganised proliferation of tenocytes, disrupted organisation of collagen fibres, and an increase in the non-collagenous matrix, and neovascularisation. Usually, there is no evidence of inflammation, but the cause is thought of as a failed healing response 1. Repetitive microtrauma from unusual or excessive mechanical loading is deemed to be a causative factor.
Location
It particularly affects the mid and distal portions of the tendon 2.
Radiographic features
Ultrasound
Often shows thickening and rounding of the affected portion of the tendon. The cutoff value of 1 cm in anteroposterior diameter is usually used for diagnosis. There is also evidence of neovascularisation, which, if present, is usually indicative of a poorer outcome and more severe clinical symptoms. Additional signs include increased Kager fat pad echogenicity and thickening of a hypoechoic paratenon.
MRI
Can show increased intratendinous signal and tendon enlargement, with oedema in Kager fat pad in cases of tendinosis.
Juxtacortical (periosteal) Chondroma
Non-contrast MR of the knee shows a 2.5 x 1.8 cm T2 hyperintense, T1 intermediate multilobulated mass at the anterolateral proximal right tibial shaft, which appears to arise from the cortex or periosteum. There is T2 hyperintensity within the tibialis anterior muscle surrounding the mass, consistent with intramuscular oedema. There is no evidence of significant bone marrow oedema of the tibia.
Case Discussion
The small lytic mass associated with the anterolateral cortex of the tibia metaphysis shows evidence of chondroid-type mineralisation by radiography (“rings and arcs” pattern of calcification). The MR images nicely demonstrate the lesion originating from the superficial cortex, without intramedullary invasion. The absence of associated reactive marrow oedema is suggestive of a benign aetiology. The MR signal characteristics (T1 intermediate, T2 hyperintense) are typical of chondral tissue.
The differential diagnosis includes:
periosteal (juxta-cortical) chondroma
chondromyxoid fibroma (intramedullary >> juxta-cortical location, sclerotic rim, and radiographically apparent chondroid matrix is uncommon)
non-epiphyseal chondroblastoma (classically T2 hypointense due to immature chondroid matrix, usually associated with reactive marrow oedema)
The presentation and imaging appearance, including the lobulated and exophytic morphology, are most consistent a benign juxtacortical chondroma.
Histology
Soft, gray mass associated with a piece of bone. The mass measures approximately 2.0 x 2.0 x 1.7 cm. Sections show a cartilaginous neoplasm that has some degree of nuclear atypia and areas of myxoid changes. However, it is known that benign periosteal or juxtacortical chondromas can have atypia. Furthermore, the mass is relatively small, measuring 2.5 cm by imaging, and is well-circumscribed. Immunostains (Ki-67, p53) were indeterminate.
DIAGNOSIS: juxtacortical (periosteal) chondroma.
Juxtacortical chondroma
Dr Sarah Robertson and Dr Yuranga Weerakkody◉ et al.
Juxtacortical chondromas, also known as periosteal chondromas, are rare benign chondral tumours that arise from the periosteum of tubular bones. They are thought to account for ~2% of benign bone tumours.
Epidemiology
They tend to present around the 2nd to 4th decades. There is a recognised male predilection 1.
Location
Typical sites include 3:
proximal humerus and distal femur (70%)
phalanges (25%)
tibia
radius
ulna
Radiographic features
Plain radiograph
may be seen as a saucerisation of the adjacent bony cortex with a sclerotic periosteal reaction
distinct soft tissue mass may be difficult to identify
matrix calcification may be seen in ~50% of cases; as with all chondroid lesions, this tends to be ring and arc
most lesions are <3 cm in size 1
MRI
Typically seen as a soft tissue lesion abutting the cortex and may better demonstrate evidence of pressure erosion of neighbouring bone. Often has a lobulated configuration. Tends to lack associated medullary bone or soft tissue oedema.
Signal characteristics include 8:
T1: typically iso to low signal relative to muscle
T2/T2*: high signal but with low signal areas representing calcification
T1 C+ (Gd): heterogeneous and tends to show peripheral predominant contrast enhancement
Treatment and prognosis
They are benign lesions, however, may be similar in imaging and histopathologic appearance to juxtacortical chondrosarcomas. Local excision is often the treatment of choice. Once resected lesions usually do not recur.
Differential diagnosis
Imaging differential considerations include:
periosteal osteosarcoma: lobulated margins and high T2 chondral nodules of periosteal chondroma are absent
non-epiphyseal chondroblastoma: typically associated with reactive marrow oedema on MR
juxtacortical chondrosarcoma: often larger than 3 cm (mean size 5.5 cm)
bizarre parosteal osteochondromatous proliferation (Nora lesion): for phalangeal lesions
cortical desmoid: for the posteromedial distal femoral lesions
tenosynovial giant cell tumour: for phalangeal lesions
hyperextension injury
Bone bruise pattern
knee
hyperextension injury
direct force to anterior tibia with foot planted
contusion pattern: “kissing contusions” of anterior tibial plateau and anterior femoral condyle
associated with ACL, PCL, meniscal injuries, and in severe cases knee dislocation
CPPD
- chondrocalcinosis
- subchonral cysts with little osteophyes
- can mimic OA, RA , Gout or chots
- any joint
- calc in and around joints: hyaline cartilage, fibor cartilage, syndoivum, capsile, tendons ligaments
- Can resemble OA, but WORSE in the patellofemoral joint
- DDx
- Gout
- Charcot Earth (CPPD is AKA psuedocharcot)
- OA
- RA
- Septic arthritis
What are the three types of Partial thickness tear?
RE SHoulder USS
7.3. Partial-Thickness Tears
Partial-thickness tears are defined as a disruption of tendon fibers that does not allow communication between the glenohumeral joint cavity and the subacromial-subdeltoid bursa. Partial tears may be intrasubstance, or extend to either the bursal or articular surfaces of the tendon (figure 1-39). Articular surface partial-thickness tears most commonly affect the anterior aspect of the critical zone of the supraspinatus and are more prevalent than intrasubstance and bursal surface tears. Theoretical basis for the increased frequency of articular surface tears include peculiar histological and biomechanical properties. The bursal side layers are primarily composed of tendon bundles, which are resistant to rupture and may elongate under tensile load, whereas articular side layers are composed of a complex of tendon fibers, ligaments, and joint capsule, which is more susceptible to tear.176
Psoriatic arthritis
- asymmetric
- oligo or poly arthropathy
- DIP (primarily) and PIP
- can mimic OA
- proliferative bone chagnes
- periostitis (radio styloid)
- osteolysis Pencil in cup
- enthesitis dactylitis
- RF neg
*
Intertarsal arthropathy
- Matches the prox zone of the hands
- Has the same ddx (RA and CPPD) as well as a few more
- Neuropathic charcot arthropay
- Disorgansies joints, fragmented and sclerotic bone. Starts with systic change
- CPPD
- Cystic change, can mimic charcot Earth. Aka pseudocharcot
- Gout
- OAL usually secondary (coalition, truam, tibiaasias posterior dysfunction (pes planus)
- Neuropathic charcot arthropay
boutonniere’s Syndrome
Boutonnière deformity is the eponymous name of a musculoskeletal manifestation of rheumatoid arthritis presenting in a digit, with the combination of:
flexion contracture of a proximal interphalangeal (PIP) joint
extension of a distal interphalangeal (DIP) joint
Pathology
Boutonnière deformities occur when the central slip of the extensor digitorum tendon is torn or stretched resulting in PIP joint flexion. Increasing PIP joint flexion causes further extensor retinaculum damage resulting in “buttonholing” of the proximal phalanx between the lateral bands of the extensor tendon. Secondary DIP joint extension then occurs 4.
Etiology
inflammatory arthritis 4
central slip of extensor digitorum tendinopathy or rupture 4
History and etymology
“Boutonnière” is French for buttonhole. The appearance apparently reminded (presumably French-speaking) surgeons of a buttonhole.
Fibrous Dysplasia
Segond fracture
Dr Subhan Iqbal◉ and Assoc Prof Frank Gaillard◉◈ et al.
Segond fracture is an avulsion fracture of the knee that involves the lateral aspect of the tibial plateau and is very frequently (~75% of cases) associated with disruption of the anterior cruciate ligament (ACL). On the frontal knee radiograph, it may be referred to as the lateral capsular sign.
Clinical presentation
Contrary to the more common causes of an ACL tear, which typically involve a valgus stress 3, a Segond fracture usually occurs as a result of internal rotation and varus stress 1,4. Typically these injuries are seen in two settings:
falls
sports: especially soccer, skiing, basketball and baseball 4,10
Pathology
Somewhat surprisingly, the exact cause of a Segond fracture continues to be contentious. The conventional teaching has been that it is the result of avulsion of the middle third of the lateral capsular ligaments 7. Other candidate structures include the iliotibial band and anterior oblique band of the fibular collateral ligament 3.
In 2017, the ALL expert group released a consensus paper 8 recognising the presence of the anterolateral ligament 9, and noted a constant attachment to the lateral meniscus. However, the ALL is inconsistently identified on MRI 7.
Radiographic features
Plain radiograph
The classical appearance of a Segond fracture is that of a curvilinear or elliptic bone fragment projected parallel to the lateral aspect of the tibial plateau. This has been referred to as the lateral capsular sign 1, which is best seen on the anteroposterior view of the knee.
MRI
MRI is essential in all cases of Segond fractures to identify internal derangement. Disruption of the ACL is the most common, however, there are additional frequently encountered injuries. Associated injuries include 1,3:
ACL tear
most common associated injury
75-100% of cases 6
medial or lateral meniscal tear
66-75% of cases 6
posterior horn most common
avulsion of ACL from the tibial attachment: rare
avulsion of fibular attachment of the long head of biceps femoris
avulsion of the fibular collateral ligament
Treatment and prognosis
Although the fracture itself is small, the extensive ligamentous injury associated with it usually requires surgical intervention, to correct anterior rotational instability 4. Healing of the Segond fracture is associated with a particular bone excrescence arising below the lateral tibial plateau.
History and etymology
First described by Paul Ferdinand Segond, French surgeon (1851-1912) based on cadaveric experiments 1,2,4.
Differential diagnosis
Imaging differential considerations include:
arcuate sign: avulsion fracture of the head of the fibula 5
fragment orientated more horizontally
Olecranon bursitis refers to inflammation of the olecranon bursa. The olecranon bursa is a subcutaneous sac that overlies the olecranon process and contains a small amount of fluid to prevent against injury of subcutaneous tissue and skin from the uncovered bony olecranon.
Pathology
Aetiology
Bursitis can develop secondary to many causes:
excessive use - e.g. student’s elbow
trauma
acute trauma
repetitive trauma
infection - septic
inflammation - rheumatoid arthritis, gouty arthropathy and CPPD
Radiographic features
Plain film
Lateral radiograph of the elbow reveals soft tissue swelling superficial to the olecranon. Traumatic fracture or calcification in gout or CPPD may be evident.
Ultrasound
May show a fluid collection in the olecranon bursa, features of synovial proliferation and/or hyperaemia. A small proportion of patients may also show presence of an associated loose body or features of associated triceps tendonitis (+/- calcifications) 2.
Pivot shift
ACL
MCL
Meniscus
Posterior Lateral corner injuries
Structures
- PLC
- LCL
- BF
- Pop t
- arcuate lig
- popliteofibular lig
- Common peroneal nerve may be injured
Flap tear
Dr Balint Botz ◉ and Dr Yuranga Weerakkody◉ et al.
A flap tear is a type of meniscal tear which usually comprises of a displaced flap fragment.
horizontal tears can give rise to flap tears, which can be classified as superior or inferior when displaced. Superior flaps arise from the superior surface of the meniscus and inferior flaps from the inferior surface.
oblique tears could also give rise to flaps which are mechanical unstable and associated with mechanical symptoms 2
Location
Flap tears occur six to seven times more frequently in the medial meniscus 3.
Mnemonic For Monteggia and Galleazii Fractures
- MUGR
- “Mugger”
- Monteggia = Ulna fracture and radial dislocation
- Galleazzi = Radial fracture with Ulnar dilocation
- A in Monteggia = proximal in the alphabet = proximal findings
- Z is distal in the alphabet = distal findings.
Periosteal Chondromas
A rare type of chondroma (benign chondrogenic lesion) which occur on surface of long bones
Epidemiologydemographics
occur in 10-20 year-olds
locationsurface of long bones (under periosteum) in distal femur, proximal humerus, and proximal femur
59% of lesions in proximal humerus
other locations in the hand (metacarpal or phalanges)
Presentation
Symptoms
many are painful secondary to irritation of tendons
Imaging
Radiographs
well-demarcated, shallow cortical defect
punctate mineralization (calcification) in 1/3.
saucerization of underlying bone
radiographs important to differentiate from chondrosarcoma (histology may be similar)
Studies
Histologysimilar to enchondroma except for increased cellularity and more malignant looking cells (can look like chondrosarcoma)
bland hyaline cartilage
small chondroid cells in lacunar spaces
Treatment
Operativemarginal excision including underlying cortexindications
severe symptoms interferring with function
technique
lesion will recur if cartilage is left behind
bone graft any large defects
Case courtesy of Dr Andrew Dixon, Radiopaedia.org, rID: 62021
Picture frame vertebral body
Dr Yuranga Weerakkody◉ and Dr Mohammad Taghi Niknejad et al.
Picture frame vertebral body is a radiologic appearance in which the cortex of the vertebral body is thickened. This sign can be seen in patients with Paget disease.
It is a result of disorganised new cortical bone formation after excessive osteoclastic activity causes the resorption of normal bone.
Radiographic features
At radiography, this results in increased opacity of the cortex on all sides of the vertebral body.
Differential diagnosis
rugger jersey spine
the characteristic sclerosis is seen only at the superior and inferior vertebral endplates
Phocomelia
Dr Karwan T. Khoshnaw and Dr Yuranga Weerakkody◉ et al.
Phocomelia is an extremely rare congenital skeletal disorder that characteristically affects the limbs. It can affect either the upper limbs or lower limbs or both. Phocomelia is also a descriptive term to describe the characteristic limb anomalies occurring with its associated conditions.
Pathology
It characteristically manifests as a deficiency or shortening of the proximal to mid portions of the limbs.
Associations
Phocomelia can occur sporadically. However, recognised associations include:
thalidomide embryopathy: most common cause of historically
Roberts syndrome
TAR syndrome 4
Grebe syndrome
Holt-Oram syndrome
DK phocomelia syndrome/von Voss-Cherstvoy syndrome
Schinzel-phocomelia syndrome 5
Radiographic features
Antenatal ultrasound
Classically with upper limb involvement, the hands are present, but with variable deficiency and or foreshortening of the arm and/or forearm. The hands may be of normal or abnormal morphology.
History and etymology
Derived from the Greek phoco meaning “seal” and melia meaning “limb”.
Differential diagnosis
congenital limb amputation
amelia
Findings: A bony overgrowth extending outwards from the surface of the right radial head away from the joint. The appearance is typical for an osteochondroma (exostosis). Cross-sectional imaging, preferably MRI, is advised to measure the cartilage cap, especially if there is a history of pain.
Epidemiology
Osteochondromas develop during childhood (period of most rapid skeletal growth), but once formed remain for the rest of the individual’s life. They can present at any age and are most frequently found incidentally.
They are usually sporadic, but can be part of:
hereditary multiple exostoses (HME): also known as diaphyseal aclasis
Trevor disease: also known as dysplasia epiphysealis hemimelica
Malignant transformation occurs in the cartilage cap, and is uncommon in sporadic solitary osteochondromas (~1%), whereas in the setting of hereditary multiple exostoses the rate is much higher (5-25%) 5.
Clinical presentation
Symptomatic presentation is either due to mechanical effects of the lesion, fracture, or malignant transformation.
Mechanical symptoms include:
impingement upon nearby structures:
nerve compression
vascular compression
reactive myositis
palpable lump
bursal formation and bursitis
Fractures occur typically through the neck of pedunculated lesions.
Ongoing growth and or pain after skeletal maturity has been reached is suspicious for malignant degeneration.
Pathology
Osteochondromas are considered a chondroid neoplasm and are primarily a part of the growth plate which separates and continues growing independently, without an associated epiphysis, usually away from the nearby joint. The medullary cavity is continuous with the parent bone, and hyaline cartilage caps them. Osteochondromas can be congenital or occur as a result of previous trauma to the growth plate, including previous irradiation 3,4.
Location
They most commonly arise from the appendicular skeleton, especially around the knee 3:
lower limb: 50% of all cases 3
femur (especially distal): most common: 30%
tibia (especially proximal): 15-20%
less common locations: feet, pelvis
upper limb
humerus: 10-20%
less common locations: hands, scapula
spine: the posterior elements of the spine are an uncommon but not rare site for these tumours
Radiographic features
Plain radiograph
An osteochondroma can be either sessile or pedunculated and is seen in the metaphyseal region typically projecting away from the epiphysis. There is often associated broadening of the metaphysis from which it arises. The cartilage cap is variable in appearance. It may be thin and difficult to identify, or thick with rings and arcs calcification and irregular subchondral bone.
New cortical irregularity or continued growth after skeletal maturity has been reached, as well as frankly aggressive features (e.g. bony destruction, large soft tissue component, metastases) are all worrying for malignant transformation.
Findings: A displaced and overlapped fracture of the ulnar shaft is present. Additionally, the radial head is dislocated anteriorly.
Case credit: Frank Gaillard, rID: 8012
Key Points
these are typically seen in children and warrant close investigation of both the elbow and the wrist
there is a chance the patient could have an associated distal radius injury as is the case in some studies (24%)
monteggia fracture-dislocations are not easy to image and require highly modified techniques such as horizontal beam lateral
Osteochondral injury staging
Dr Mostafa El-Feky◉ and Assoc Prof Frank Gaillard◉◈ et al.
Osteochondral injury staging system for MRI attempts to grade the stability and severity of osteochondral injury and is used to plan management.
stage I
injury limited to articular cartilage
MRI findings: subchondral oedema
x-ray findings: none
stage II
cartilage injury with associated subchondral fracture but without detachment
thin sclerotic margin
x-ray findings: usually none; may see fracture as sclerotic or osteopenic area
two subtypes 2,3
type A: cystic on CT and/or oedema on MRI
type B: non-displaced and incompletely undercut by fluid (MR) or lucency (CT), with an open connection to the articular cartilage (essentially 2a without oedema on MRI)
stage III
detached, non-displaced fragment
MRI findings: high signal around osteochondral fracture (rim sign) but not displaced
x-ray findings: slight lucency between osteochondral fragment and remainder of the bone
stage IV
osteochondral fragment displaced
usually joint effusion present, surrounding fragment and filling donor site
x-ray findings: increased lucency between osteochondral fragment and remainder of the bone, or loose body with donor site irregularity
stage V
subchondral cyst formation
secondary degenerative change
x-ray findings: secondary osteoarthritis
increased sig in meniscus
- can be normal in kids and young adults. normal gascularity flow of suynovial lfludi
- Signs of OA
- myxoid degn
- Evidence of trauma
- contusion
- Meniscal cyst
- meniscal tear
- Contacts an articular surface on more than 1 slice
- meniscal tear
- if see in only 1 slice
- around 50% chance of a tear
*
- around 50% chance of a tear
- Hydroxyapatite deposition disease (HADD)
- globular foci of calcification in the expected location of the supraspinatus (white) infraspinatus (black arrow) and pect major (arrowheads tendon).
- HADD
- no know cause.
- 2/3 assymptomatic
- can be the cause of acute pain and a/w fever, increased ESR and CRP.
- AKA calcific tendonitis, hydroxyapatite rheumatism, calcific periarthritits and pertendinitis calcarea.
- calc appears clowud like and amorphous and can involve the tendon, ligament, bursa or. joint capusle.
- intraarticuilar deposition can destroy the point space, resulting in a condition referred to as Milwaukee shoulder.
- The shoulder is most commonly involved.
- On CT accompanying erosion of the underlying bone canbe seen.
- Electron microscopy needed to dx.
- Can appear aggressive erosive esp when involveing the pect major origin which can be mis interpreted as malignancy.
- Pope Jr, T., 2015. Aunt Minnie’s Atlas And Imaging-Specific Diagnosis. Philadelphia: Wolters Kluwer.
Grystal induces arthoropaties
- Gout mono sodium
- Pseudogeout: CPPD intra articular
- HADD
Complex regional pain syndrome
Dr Balint Botz ◉ and Assoc Prof Frank Gaillard◉◈ et al.
Complex regional pain syndrome (CRPS), also known as Sudeck atrophy, is a condition which can affect the extremities in a wide clinical spectrum. CRPS is principally a clinical diagnosis seen more commonly in females than males with a mean age of presentation of 50 to 70 years 12. No one imaging study is sensitive or specific to rule in or rule out the syndrome.
Terminology
Two types of CRPS have been described 8:
type 1: no underlying single nerve lesion (formerly known as reflex sympathetic dystrophy)
type 2: underlying nerve lesion identified (formerly known as causalgia)
Clinical presentation
Patients present after an initiating event (see causes below) with symptoms of more than 6 months duration such as oedema, changes in skin blood flow, abnormal motor activity, allodynia or hyperalgesia 11. Symptoms are often out of proportion to the initiating event and not limited to a single peripheral nerve 8.
Pathology
Aetiology
trauma: often minor
surgery 11
idiopathic: immobilisation
unknown in many cases
CNS disorders
myocardial infarction
Location
Occurs in hands and feet distal to the injury.
Radiographic features
Plain radiograph
severe patchy osteopenia, particularly in the periarticular region
soft tissue swelling, with eventual soft tissue atrophy
subperiosteal bone resorption
preservation of joint space
It is important to differentiate this from disuse osteopenia since the clinician could initiate aggressive physical therapy for the latter.
MRI
patchy bone marrow oedema signal (particularly subcortical), although bone marrow signal may be normal in some cases
soft tissue oedema and enhancement
skin thickening
joint effusion
synovial hypertrophy
muscle atrophy in later stages
Nuclear medicine
increased uptake on all three phases
diffusely increased juxta-articular activity around all joints of a hand or foot on delayed images is the most sensitive indicator
Treatment and prognosis
In most cases, a multidisciplinary approach is required whereby a combination of various treatments may be employed, such as physical therapy, systemic or regional medications, sympathectomy or spinal cord stimulation, and psychotherapy. Interventional radiology can offer pain relief by peripheral nerve block procedures.
References
Case courtesy of Dr Angela Byrne, Radiopaedia.org, rID: 8112
Chondroblastoma
https://radiopaedia.org/cases/chondroblastoma-distal-femur-2?lang=us
LCH
- Gouty arthritis
• monosodium urate crystals in synovial fluid
• asymptomatic periods from months to years
Target areas: commonly CCMC +all hand joints
‘./ development of chronic tophaceous gout
=lobulated soft-tissue masses
‘./ well-defined eccentric erosions with overhanging edge
(often periarticular) + sclerotic margins
‘./ preservation of joint spaces
‘./ absence of osteoporosis
‘./ most extensive changes in common carpometacarpal
compartment:
‘./ scalloped erosions of bases of ulnar metacarpals
- Patella dislocation relocation (PDR)
- kissing contusions to the medial patella facet and the lateral femoral condyle
- large lipohaemarthrosis
- sprain/tear of the medial patella retinaculum.
- hoffas fat pad injury
- redislocation occurs in up to 63% of patients
- A/W ACL tears
Pope Jr, T., 2015. Aunt Minnie’s Atlas And Imaging-Specific Diagnosis. Philadelphia: Wolters Kluwer.
Parrot beak meniscal tear
Dr Magdalena Chmiel-Nowak◉ and Dr Yuranga Weerakkody◉ et al.
Parrot beak meniscal tear is a type of radial meniscal tear with a more oblique course, which on axial images gives the characteristic appearance of a curved V, similar to a parrot’s beak. As it is obliquely orientated in relation to the coronal and sagittal plane, it results in a marching cleft sign on sagittal images. This type of tear is usually symptomatic, as the partially torn meniscal flap in unstable.
Practical points
Some authors advise that the term should be reserved for arthroscopy reports, and not used in MRI reports as a meniscal tear pattern descriptor 1.
Pearls re enchondrona & malignant transformation
- In the absence of a fracture, a painful encondrona is considered malignant until proven otherwise.
- Malignant transformation occurs but is rare.
- Malignant transformation is more common in central lesions
haemochromatosis.
Overhanging (hooked) osteophytes of the metacarpal heads of the right index.
Case Discussion
The overhanging osteophytes (a.k.a. hooked or beak-like osteophytes) at the heads of the metacarpals of index and long fingers are typical for haemochromatosis. Chondrocalcinosis is not prominent in this case. The main differential diagnosis of haemochromatosis is CPPD.
References
causes of increased bone denisty
Generalised increased bone density (mnemonic)
Dr Sachintha Hapugoda◉ and Dr Maunil Ajay Bhuta et al.
A handy mnemonic for causes of generalised increased bone density / osteosclerosis:
Regular Sex Makes Occasional Perversions Much More Fun, Happening and Lovely
Mnemonic
R: renal osteodystrophy (case 1 and 2)
S: sickle cell disease, salt and pepper skull (case 2)
M: metastasis (osteoblastic/sclerotic)
O: osteopetrosis
P: pyknodysostosis; Paget disease
M: myelofibrosis
M: mastocytosis
F: fluorosis
H: hyperparathyroidism; hypervitaminosis A and D
L: lymphoma
Case 1:
Plain X-ray hands of a young patient with CRF shows signs of secondary hyperparathyroidism:
irregular, frayed and ill-defined cortical outline, pronounced at radial aspect of middle phalanges –> subperiosteal bone resorption
multiple lytic expansile lesions –> brown tumours (arrows)
osteosclerosis
accentuated trabecular pattern non-essential trabeculae are resorbed; those that remain appear prominent)
Case Discussion
Renal osteodystrophy is a constellation of musculoskeletal abnormalities that occur in patients with chronic renal failure.
Manifestations include:
osteomalacia (adults) / rickets (children)
secondary hyperparathyroidism: bone resorption, osteosclerosis, soft tissue & vascular calcifications and brown tumours
aluminium intoxication if the patient is on dialysis
Comment:
Subperiosteal bone resorption is the hallmark of HPTH and is first identified in hands.
Ivory vertebra (ewing sarcoma 1st case, BrCa second case)
Dr Mostafa El-Feky and Radswiki◉ et al.
The ivory vertebra (also known as ivory vertebra sign) sign refers to the diffuse and homogeneous increase in opacity of a vertebral body that otherwise retains its size and contours, and with no change in the opacity and size of adjacent intervertebral discs.
Pathology
Etiology
The cause for an ivory vertebra depends on the age of the patient 1.
Pediatric
lymphoma: commonest cause, usually Hodgkin lymphoma
osteosarcoma
osteoblastoma
blastic metastatic disease
neuroblastoma
medulloblastoma
Ewing sarcoma (rare)
Adult
osteoblastic metastases
prostate cancer
breast cancer
lymphoma (usually Hodgkin lymphoma)
tuberculous spondylitis
hemangioma
chordoma
Paget disease of bone
vertebral body expansion (unlike hemangioma)
coarsened trabeculae
SAPHO syndrome 3
Rarely, the ivory vertebra can also be seen in 4:
primary bone sarcoma
sarcoidosis
systemic mastocytosis
Radiographic features
Plain radiograph and CT
Plain radiographs and CT will demonstrate diffuse sclerosis of the vertebral body with variable involvement of the posterior vertebral elements.
MRI
MRI demonstrates hypointense signals within the corresponding vertebra which is directly proportional to the degree of sclerosis of the vertebral body.
lateral patellar dislocation
lateral patellar dislocation
twisting injury to flexed knee
anterolateral lateral femoral condyle and inferomedial patella
associated with medial patellar retinaculum +/- medial patellofemoral ligament injury +/- medial patellotibial ligament injuries
References
posterior accessory ligs
which can look like tear
Wrist berg behind PCL
Humpry Anterior
One or the other present in 75% of cases
poly ostotic
osseous expansion
ground glass appearance
this is Fibrous dysplasia
Types of primary osseous osteosarcoma - 5
95% of OSA = Primary Osseous
- Conventional OSA
- Low grade OSA
- telangiectatic OSA
- Small Cell OSA
- multicentric OSA
Parosteal osteosarcoma
Dr Matt A. Morgan◉ and Assoc Prof Frank Gaillard◉◈ et al.
Parosteal osteosarcoma is a subtype of osteosarcoma and arises from the outer layer of the periosteum.
Epidemiology
It is the most common type of juxtacortical or surface osteosarcoma and accounts for ~5% of all osteosarcomas. It typically presents in early adulthood and middle age with a peak incidence in the third decade. It affects females slightly more than males 9.
Clinical presentation
Patients usually present with a painless, slowly enlarging mass 9.
Pathology
They are usually located at the metaphysis (80-90%), most commonly at the posterior aspect of the distal femur (60%), followed by either end of the tibia, and then the proximal humerus.
They are composed of a dense osteoid component attached to the outer cortex over a narrow zone. Parosteal osteosarcoma originates from the outer fibrous layer of periosteum. It exhibits extensive bone matrix and minimal fibroblastic cellular atypia, and as such is considered to be a low-grade tumour.
Radiographic features
large lobulated exophytic, ‘cauliflower-like’ mass with central dense ossification adjacent to the bone
string sign: thin radiolucent line separating the tumour from the cortex, seen in 30% of cases
tumour stalk: grows within the tumour in late stages and obliterates the radiolucent cleavage plane
+/- soft tissue mass
cortical thickening without aggressive periosteal reaction is often seen
tumour extension into the medullary cavity is frequently seen
MRI
It exhibits predominantly low signal intensity both on T1 and T2 weighted imaging. High signal intensity on T2 is suggestive of a high-grade tumour.
Treatment and prognosis
Parosteal osteosarcomas are usually low-grade lesions are usually treated with surgical resection and no neoadjuvant chemotherapy or radiation. As they are frequently metaphyseal in location, large parosteal osteosarcomas or those with deep medullary invasion may require limb salvage, including joint replacement.
Parosteal osteosarcomas have an excellent prognosis (80-95% long-term survival).
Differential diagnosis
On imaging consider
cortical desmoid: avulsive injury of the posterior femoral cortex
myositis ossificans: the ossification pattern of parosteal OS is the radiographic inverse of that seen in myositis ossificans, with the densest ossification in the centre of the lesion and the least radiopaque bone at the periphery (eggshell pattern); there is also often a history of trauma, progressive decrease in size or constant size and significant oedema in early stages on MRI.
sessile osteochondroma: parosteal OS lacks corticomedullary continuity between the tumour and the underlying medullary canal.
juxtacortical chondrosarcoma
high-grade surface osteosarcoma
parosteal lipoma: radiolucent mass adjacent to the cortical surface on plain film and on cross-sectional imaging will usually show a definite fat component 2
- GCT
- subarticular
- Geode
- synovial fluid escaping into juxtartiular surface
- OM
- any age
- aggressive
- lytic
- Pagets
- thickened cortex
- osseos expansion
- coarsend trabecular
- Flame sign of lytic phase pagets disease
what is the difference between a wide and narrow zone of transition?
