Archive for category: Uncategorized

Core topics in orthopaedics

Unicameral Bone Cyst (UBC)

– solitary, fluid-filled cystic lesions located in metaphysis of long bones near physis in kids & adolescents
– predominantly proximal femur & proximal humerus

Signs & Symptoms:
– usu asymptomatic
– pathologic # associated with minimal trauma

Xrays:
– radiolucent, trabeculated lesion with well-defined borders surrounding by sclerotic margin
– ‘fallen leaf’ sign in pathologic #

Histology:
– lined with loose connective tissue membrane containing small numbers of fibroblasts, giant cells & hemosiderin-laden macrophages

Treatment:
– 15% will heal after # with observation alone
– treat # as you would for most #s of that region
– once # healed, aspiration & steroid injections (x 3)
– curettage & bone grafting improves healing rate & provides mechanical support

Aneurysmal Bone Cyst (ABC)

– solitary expansile lesion located in metaphysis of long bones, flat bones & vertebrae
– presents in 2nd decade
– cysts filled with blood

Signs & Symptoms:
– pain with tenderness & swelling at the site of the lesion

Xrays:
– expansile eccentric lesion surrounded by a thinned cortex with periosteal new bone formation
– CT/MRI – characteristic ‘fluid-fluid’ level
– beware of telangiectatic osteosarcoma – has fluid-fluid levels but far more aggressive looking

Histology:
– blood spaces separated by cellular septa lacking an endothelial cell lining & containing a variety of cells such as fibroblasts, multinucleated giant cells & histiocytes & metaplastic bone
– large solid cellular areas may be seen

Treatment:
– excision, curettage & bone grafting
– cryosurgery or chemical ablation may be used

Talocalcaneal joint – lateral approach

* position – supine with sandbag under buttock & table tilted 20-30 deg. away from surgeon

* incision
– curved incision 10-13 cm long on lat. aspect of ankle starting 4 cm above tip of lat. malleolus on post. border of fibula
– follow to tip of fibula & curve forward passing over peroneal tubercle parallel to course of peroneal tendons

* no internervous plane

* dissection
– avoid sural n. & short saphenous vein as they run just post. to lat. malleolus
– incise deep fascia in prox. wound to expose peroneal tendons
– continue to incise fascia following tendons
– incise inf. peroneal retinaculum in line with PB
– incise fibrous sheath over PL
– retract peroneal tendons ant.
– ID calcaneofibular lig. running from lat. malleolus to lat. surface of calcaneus
– ID subtalar joint & incise capsule

* dangers
– sural n. & short saphenous vein

Thoracolumbar Spine Fractures

Three column theory (Denis, 1984)
Ant.-ALL and ant. 2/3 vertebrae
Mid.-post. 1/3 body and PLL
Post.-bony arch, inter/supra spinous and flavum

Stability based on 2 columns.
Divided into 4 categories:
1) Compression
-compression of ant. column with intact middle column and post.
-post. column fails under tension with >40 to 50% loss of ant. height
Subtypes
A-failure of both endplates (16%)
B-failure of sup. endplate (62 %)
C-failure of inf. endplate (6 %)
D-both endplates intact (15 %)

2) Burst Fractures
-compression failure of ant. and middle columns +- post. columns
-retropulsion common
Subtypes
A-both endplates (24 %)
B-sup. endplate (49%)
C-inf. endplate (7%)
D-Burst/rotation injury (15%)
E-Burst/lateral flexion injury (5%)

3) Seat-belt injuries
Subtypes
A-one level bony injury (Chance)
B-one level ligamentous injury
C-two-level injury through bone in middle column
D-two-level injury through ligamentous middle column

4) Fracture-dislocations
-failure of all 3 columns
-high rate of neurologic injury
Subtypes
A-Flexion-Rotation
-M/P columns fail in tension and rotation and A column in flexion
B-Shear
C-Flexion-Distraction

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