Don's gem's

The Wizard's potion

These are some of Don's interesting comments from the Friday morning case conferences.  Any errors in this section are solely the poor recording of otherwise accurate comments, due to the pressure of the quantity of interesting comments.  This section is updated weekly.

To see the cases click here

This section has outgrown it's page and been subdivided. Previous sections are linked below.

2001             July August September October November December
2002 Jan Feb March April May June July August September October November December

This page last updated on 05/06/2003 09:56:57 PM


August 23rd 2002 from Christine Lamoureux


  1. Subscapularis tears: the definition of a complete tear is one in which there is no subscapularis tendon attachment to the humerus; a full-thickness tear does not necessarily have to be complete; a combination of complete and full-thickness tears can result in displacement of the biceps tendon into an intraarticular position proximally and extraarticular position distally, for example.
  2. Young adult patient slammed hand in a car door and has masses dorsal to the second and third metacarpophalangeal joints that are dark on T1 and bright on T2 with fluid surrounding the flexor tendons: differential includes pannus associated with JRA vs hematoma (but the injury is subacute), vs multifocal PVNS.
  3. Haglund’s disease; the "pump bump" comprised of thickening of the posterosuperior calcaneous and Achilles tendon. This phenomenon is also associated with superficial Achilles bursitis and retrocalcaneal bursitis. The differential includes seronegative spondyloarthropathies.
  4. Hypoplastic glenoid neck and a "dentate" morphology of the glenoid fossa may be associated with multidirectional instability patterns, secondary OA, and rotator cuff tears. This variant morphology is often an incidental finding on plain films and is comprised of a broad glenoid (resembling acetabular dysplasia) and the "dentate," or tooth-like articular surface. Associated findings include a hypoplastic humeral head, bowing of the acromion and clavicle (such as may be seen in Erb’s palsy). It is questionable how many of such cases are symptomatic. There can also be an abnormal anterior labrum resulting in anterior instability, or posterior labral pathology with posterior instability. The latter has been associated with an enlarged labrum separated from the glenoid margin with a cleft, which may be developmental. According to Dr Hughes, further characteristics of the hypoplastic glenoid include bilaterality and posterior angulation of the glenoid with respect to the rest of the scapula.
  5. Seronegative spondyloarthropathies differ from RA in that they may be characterized by early marrow edema, bony proliferation, "whiskering" periostitis and soft tissue swelling ("sausage digits") before the joint spaces become very abnormal.
  6. Shoulder MR arthrograms: it is often helpful to compare the T1 and fluid-sensitive sequences side-by side. A disadvantage of arthrography is the fact that evaluation of bursal-sided irregularities of the rotator cuff can be obscured.. These bursal-sided tears are not well described but can be partial with associated tendon retraction. A "rim-rent" tear is an articular-sided tear that is described as laminated.
  7. Stages of idiopathic calcific tendonitis: first the tendon accumulated calcium, then there is partial extrusion into the bursa, and finally involvement of the bursa itself. MRI with Gad is useful for evaluating whether there is associated inflammation to explain a patient’s symptoms.
  8. How to distinguish a healing fracture from osteomyelitis on MRI: a debated issue with no real consensus at our conference. Dr Resnick mentions literature by Mark Schweitzer re the usefulness of the T1 sequence. Dr Hughes suggests using T1 fat saturation images both pre and post-contrast. Dr Pathria suggests "a needle." She states that T1 pre and post contrast fat sat sequences are useful in the setting of evaluation of knee arthrograms to evaluate for retears.
  9. Infarcts (osteonecrosis) of the femoral condyles: assume that these are related to steroid use or alcohol. Literature supports that the lateral femoral condyle is more often involved that the medial. The femur and tibia can both be involved, but involvement of the patella and fibula is rare. The "double line" sign is a topic of debate: described at U. Penn as a T1 dark band with inner high T2 signal. Dr Pathria believes this is a real phenomenon, not due to just chemical shift artifact, and that the high signal band represents healing. Dr Resnick states that infarct can be difficult to distinguish from fracture at times, and that an osteochondral fracture is in the differential when a half-moon shape pattern of signal abnormality is adjacent to the articular surface if no history is given.
  10. Legg Perthes: definition of the "sagging rope" sign: this may represent a ring-like pattern of osteophytes at the femoral head/neck junction and may be seen in cases of OA as well. It is unclear if this sign as described referred to the surface of the femoral head or to osteophytes.
  11. Be careful when describing calcification in the region of the distal ulna as within the TFCC as there are many causes of calcification in this region.
  12. There is an association of gout with psoriatic arthritis but not with CPPD.
  13. Lunotriquetral contact (elongation on a frontal film) is a secondary sign of partial coalition.
  14. The elbow has three fat pads: 2 anterior and one posterior. In a normal lateral radiograph the anterior radial and coronoid fat pads are superimposed, and the posterior olecranon fat pad is not seen.
  15. Classic findings in amyloid arthropathy: shoulder masses ("shoulder pads"), involvement of the wrist resulting in carpal tunnel pathology, the spine and the hip (can result in pathologic fractures of the femoral necks).
  16. In ankylosing spondylitis, the size of syndesmophytes relates to the degree of facet ankylosis. Also, in AS the symmetry of the SI joint involvement is overrated as a feature. In the spine, pseudo-pseudoarthroses may occur when 2 levels are involved without involvement of the intervening level.
  17. Hydroxyapatite deposition may occur at one site and is not necessarily associated with systemic disease. It can appear unchanged for years or can resolve.
  18. Gout-associated soft tissue densities may be secondary to the density of the urate crystals themselves (160 HU) . Saturnine gout refers to that which was associated with drinkers of moonshine.
  19. Distal clavicular resection with acromioplasty is performed in some cases of impingement syndrome. The radiographic appearance can be confused with distal clavicular resorption secondary to RA, post-traumatic resorption, hyperparathyroidism or scleroderma (although these latter 2 processes usually taper it).

August 16th 2002 from Christine Lamoureux

  1. Rotary Fixation of the Atlanto-axial joint: plain film findings are a persistent asymmetry of the atlantoaxial space on the open-mouth view imaged in both obliquities. The lateral mass that is elevated, foreshortened and closer to the odontoid is the one that has moved anteriorly. The finding of asymmetry on a frontal view alone is not diagnostic. CT is useful for evaluation of equivocal findings.
  2. Silastic Synovitis: fragments of a silastic implant appear low signal on MRI.
  3. Amyloid Arthropathy: the case shown demonstrated cystic changes in the carpal bones and distal radius. This type of arthropathy was more common 15 years ago that it is today because of a different type of dailysate that was in use…this process can involve the hip joints as well, producing "apple core" lesions of the proximal femur.
  4. Brachial plexus MRI: " Robert Taylor Drinks Cold Beer" (roots, trunks, divisions, cords, branches (an Andeas gem).
  5. Case of and enhancing osseous fragment adjacent to the fibular head with soft tissue inflammation and no history of trauma: differential includes ossicle in the biceps femoris muscle (more commonly seen in the lateral head of the gastrocnemius muscle and popliteus muscle), myositis ossificans (pseudomalignant osseous tumor of the soft tissues…but no trauma history), soft tissue osteoma or osteochondroma (rare). Favor a late stage pseudomalignant osseous tumor of the soft tissues (a benign lesion).
  6. Mass in the suprascapular and spinoglenoid notch consistent with a ganglion cyst with entrapment syndrome: these lesions can sometimes erode bone and are associated with labral pathology 87 % of the time according to Auria…
  7. Biceps tendon completely dislocated from the bicipital groove: this can be a clinical diagnosis but MRI is useful when the clinical diagnosis is unclear? The "slingshot" effect is when the tendons of both the long and short heads rupture and "the biceps ends up below the elbow." A proximal to distal approach to the pathology of a rupture is recommended. There are two intraarticular and two extraarticular mechanisms:

    Intraarticular: biceps tendon is in the joint, and there must be a full-thickness tear of the subscapularis

    Extraarticular: either transverse ligament disruption or a partial tear of the subscapularis fibers

  8. Benign lung nodules can be metastatic from giant cell tumor and chondroblastoma via direct invasion of the vascular tree.
  9. Inferior Glenohumeral Ligament Complex: non fat-suppressed images can be helpful to evaluate pathology in this region. Discussion re multidirectional instability and difficulty in distinguishing iatrogenic effects of capsulorrhaphy vs those attributable to trauma.
  10. Advice re improving our shoulder arthrograms: a common mistake is to place the needle too medially. The needle needs to be up against the humeral head before injecting.


July 19th 2002 Ortho

1.   Stenner's lesion is a UCL injury at the thumb MCPJ, such that the ligament is pulled off distally and ends up superficial to the aponeurosis, so that it will not spontaneously heal.  It gives a yo yo on a string sign.  Classically gamekeepers wringing the rabbits neck, now common in skiers.  Both the proper and accesory ligaments have to be torn to cause a Stenner's.  All Stenner's are surgically repaired.  Only rarely does the ligament pull off the metacarpal.  can also be a boney  avulsion.  If can radially deviate 35 degrees or show an avulsed boney fragment that is rotated, then this suggests a Stenner's rather than a simple UCL tear. 

2.   Various shapes of acromium:  Type 1; flat, Type 2; curved, Type 3; hooked, Type 4; undersurface bump at level of IS tendon.  Possibly developmental, but hooks occur at the same site as the coracoacromial ligament spurs.  Determines type of surgical excision required for SAD.  If the acromium is the cause of impingement, then it is external impingement.

3.   Patella tendon rupture is usually secondary to repetitive minor trauma and tendinosis/ tendinopathy.  Other predisposing factors for tendon rupture are:  DM, Steroids, RhA, SLE, CRF.  Possible associations are PCL tear and knee dislocation.  Results in patella alta (as does Marfan's).  Grelsamer Meadows modified Insall Salvati method states that the patella tendon (inferior tip of patella to tibial tubercle) should not be more than twice the length of the articular cartilage of the patella.  This is independant of flexion and can be used with plain film or MRI.  When repairing the tendon look for holes in patella or tibial tubercle for either primary repair or supporting box wire/merseline.

4.   Hip labral tears. Type 1; morphologically normal, central high signal,  Type 2; linear high signal going to a single surface,  Type 3; detached.  The ilio femoral ligament is the inverted V shaped ligament of Bigalow, a very strong ligament.  Clicking hip can be intra or extra articular.  Intra; labrum and degenerated ligamentum teres, extra; Psoas and ITB.  ALAB acetabular labral articular defect is fissuring of the articular cartilage adjacent to a torn labrum (and is a local secret)

5.   Ankle trauma. 

    SER I; torn anterior tib fib lig,

    SER II; oblique Fx of fibula (high posterior to low anterior at level of ankle),

    SER III; post tib Fx,

    SER IV; transverse Fx of tib malleolus or deltoid lig inj.

6.   A pillon Fx occurs in dorsiflexion.


July 19th 2002 Rheumatology

1.  Long standing AS of the Cx spine can have anterior resorption/ scalloping of the bodies.

2.  Commonest cause of secondary HOA is bronchogenic carcinoma, but the condition with the highest incidence of HOA is pleural fibroma (ass. hypoglycaemia).

3.  OA of the hand causes a medial lateral wavy appearance, but not displaced anterior/posterior.

4.  Erosive or inflammatory OA causes central collapse (erosion) and ankylosis.

5.  Gout, CPPD and HAD can all be deposited in OA joints and cause painful flare ups.

6.   Short middle phalanges can be seen with frostbite, which also cause OA.

7.  Rice bodies; RhA, TB