tibial femoral angle

The natural history of the tibial femoral angle is one of considerable genu varum or bowing at birth, approximately 15 degrees. There is gradual spontaneous correction to zero degrees at one and one-half to two years of age. During the next year, a valgus of 10 degrees to 12 degrees develops which gradually corrects to the normal adult value of 5 to 6 degrees valgus at about age seven years. This process is identical in boys and girls.

Diagnosis

Clinical diagnosis and x-rays are not required. Observation of child walking:
Knee caps point forward
Femur external
Tibial internal rotation cancels femur rotation
Foot points inward (due to tibial rotation)

Measuring degree of genu varum:
Child stands with medial malleoli touching
Measure distance between medial femoral condyles

http://www.doctorslounge.com/pediatrics/diseases/genuvar.htm

Normal limits of knee angle in white children--genu varum and genu valgum.

Normal limits of knee angle in white children--genu varum and genu valgum. ³

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Heath CH. Staheli LT. Journal of Pediatric Orthopedics. 13(2):259-62, 1993 Mar-Apr. Knee angle and intermalleolar (IM) or intercondylar (IC) distance were measured in 196 white children aged 6 months to 11 years to establish normal limits of tibiofemoral angle. Children were maximally bowlegged at * age 6 months and progressed toward approximately neutral knee angles (0 degree) by age 18 months. Greatest mean knock knee of 8 degrees was observed at age 4 years, followed by a gradual decrease to a mean of less 6 degrees at 11 years. Normal children aged 2-11 years had knock knee up to Á 12 degrees and intermalleolar distance up to 8 cm; the existence of bowlegs after age 2 years was abnormal. *

http://www.wheelessonline.com/ortho/pediatric_genu_varum

measurement of bow leg deformity

Physiological bowing and tibia vara. The metaphyseal-diaphyseal angle

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in the measurement of bowleg deformities. Levine-AM; Drennan-JC J-Bone-Joint-Surg-Am. 1982 Oct; 64(8): 1158-63 The metaphyseal-diaphyseal angle is the angle created by the intersection of a line through the transverse plane of the proximal tibial metaphysis with a line perpendicular to the long axis of the tibial diaphysis. This angle represents the degree of deformity of the proximal end of the tibia in a patient with clinical bowleg deformity and permits early differentiation between infantile tibia vara and physiological bowleg, before the appearance of the radiographic changes of tibia vara. In twenty-nine of thirty affected extremities with an initial metaphyseal-diaphyseal angle of more than 11.0 degrees, radiographic changes of tibia vara later developed. However, only three of fifty-eight extremities with a metaphyseal-diapyseal angle of 11.0 degrees or less had any of the diagnostic changes. In addition, the ratio of the metaphyseal-diaphyseal angle (proximal tibial metaphyseal deformity) to the tibiofemoral angle (deformity of the entire extremity) showed that approximately 60 per cent of the deformity in tibia vara originates in the proximal metaphysis, whereas only 20 per cent of the deformity in physiological bowing originates there. The metaphyseal-diaphyseal angle allows accurate early diagnosis of bowleg deformity, as well as accurate assessment of its progression.

normal anatomy of ankle

avascular necrosis(3)

Conventional X-ray film of right hip shows irregularity of femoral head with increased density and flattening of the articular surface consistent with an avascular necrosis of the femoral head with concomitant joint space narrowing and degenerative changes.

http://www.nature.com/bmt/journal/v31/n6/fig_tab/1703886f2.html

avascular necrosis(2)

Lateral View:
- because AP views of the hip may be difficult to interpret, it is necessary to
evaluate frog-leg lateral x-rays of the femoral head;
- cross-table lateral x-ray is not satisfactory because architectural details
of the femoral head are obscured by the soft tissues that overlie this area;
- lateral radiographs also allow staging purposes since it is often anterior segment
of the femoral head that first collapses or exhibits the crescent sign;

AP View:
- usually demonstrate the principal area of involvement;
- because anterior and posterior acetabular margins overlap the superior portion
of femoral head, subtle evidence of osteosclerotic or cystic changes in
subchondral regions may be missed;

http://www.google.com.eg/imgres?imgurl=http://www.wheelessonline.com/image7/avnn1.jpg&imgrefurl=http://www.wheelessonline.com/ortho/avascular_necrosis_of_femoral_head&usg=__Zy8D6l0UR75GIgG6jE5zfSl7W4Y=&h=467&w=604&sz=15&hl=ar&start=6&sig2=tEN6aWnvoqYeI1SgYSIKWw&zoom=1&itbs=1&tbnid=-e1pB8RHuvfvWM:&tbnh=104&tbnw=135&prev=/images%3Fq%3Davascular%2Bnecrosis%26hl%3Dar%26sa%3DG%26gbv%3D2%26tbs%3Disch:1&ei=mM2RTK_sMMGEswao0vyFCQ

avascular necrosis(1)

Avascular necrosis of the capitate

Avascular necrosis of the femoral head

Avascular necrosis of the femur

ischaemic necrosis, osteonecrosis and aseptic necrosis are synonyms for the same disease process.
Avascular necrosis (AVN) is a disease process that is characterised pathologically by bone marrow ischaemia and eventual death of trabecular bone. Radiological manifestations of AVN occur in the late stages of the disease as the bone attempts to repair itself. As bone repair occurs, weight bearing bone becomes mechanically weakened and flattened and may eventually collapse. This leads to debilitating pain and osteoarthritis.

Causes of Avascular Necrosis:AVN has several causes. Loss of blood supply to the bone can be caused by an injury - post-traumatic avascular necrosis, or by certain risk factors - non-traumatic avascular necrosis e.g. steroids, excessive alcohol use or Caisson disease (found in deep sea divers and tunnel workers dus to poor decompression giving rise to bubbles of nitrogen in the blood which block capillaries causing necrosis).

http://www.xray2.20m.com/custom2.html

Bone Tumor Diagnosis,Another view

When we are confronted with a plain film of a bone , we must think about 6 points to narrow the differential diagnosis of the case.

This six clues are as follow:

1-The first clue is to define the pattern of the bone destruction you see,if it is

a-Geographical or

b-Moth eaten or

c-Permeative.

Examples:

a-geographical lesions such as non-ossifying fibroma and esinophilic granuloma.

b-Moth eaten appearance such as

1-myeloma.

2-metastases.

3-lymphoma.

4-ewings sarcoma.

c-Permeative lesion such as Round-cell lesions .

1-Myeloma.

2-Metastases.

3-Lymphoma.

4-Ewing's Sarcoma

5-Leukaemia

6- Neuroblastoma

7-Osteomyelitis

2-The second clue is the location of the lesion,if it is

- In the transverse plane:
a) Central - Enchondroma
b) Eccentric -GCT, osteosarcoma, chondromyxoid fibroma
c) Cortical - Non-ossifying fibroma, osteoid osteoma
d) Parosteal - Parosteal osteosarcoma, osteochondroma
-In the longitudinal plane:
a) Epiphyseal - GCT, chondroblastoma
b) Metaphyseal - Osteomyelitis, osteosarcoma
c) Diaphyseal - Round cell lesions, ABC, enchondroma

3-The third clue is concerning with the type of periosteal reaction, is it unilamelated ( benign) ,multilamelated,perpendicular or with codemen triangle(malignant).

4-Clues by matrix of the lesion,which could be as follow:

a- Ossification (Osteoblastic process) - Well organized ossified mass with fluffy, cotton-like or cloud-like densities. Eg. Osteosarcoma.

b-Calcification (Cartilaginous process)- Unorganized calcified matrix which is comma-shaped, punctate, annular or popcorn-like. Eg. Enchondroma, Chondrosarcoma, Chondromyxoid fibroma.

5-Clues By Density Of Lesion

1. Sclerotic Cortical lesions- Osteoid osteoma- Brodie's abscess- Stress fracture
2. Lytic lesions in children- Eosinophilic granuloma- Neuroblastoma- Leukemia
3. Lytic lesions in adult- Metastatic lesions (Lung, Kidney, Thyroid)- Multiple myeloma- Primary bone tumor
4. Blastic lesion in children- Medulloblastoma- Lymphoma
5. Blastic lesion in adult- Metastatic disease (Breast, Prostate)- Lymphoma- Paget's disease

6. Clues by number of lesion Multiple lesion: More often benignMalignancies with multiple lesions- Metastatic disease- Multiple myeloma- Lymphoma

Summary:

Let us look at the following:

location, pattern,matrix and the density of the lesion,in addition to type of peri-osteal reaction and number of lesions.

Approach to bone lesions=figures and tables

Figure 1 :Lateral radiograph of distal portion of femur shows osteosarcoma with amorphous tumor-induced new bone formation (black arrows). Note the large soft-tissue mass (white arrows) that displaces adjacent fat. Figure 2 :Buttress periosteal reaction. (a) Diagram shows beaklike solid periosteal buttress formation (arrow). (Adapted and reprinted, with permission, from reference 2.) (b) Anteroposterior radiograph of humerus in a patient with periosteal chondrosarcoma shows periosteal buttress (short white arrow). Note well-defined saucerization of humeral shaft (black arrows) and faint mineralization of the matrix (long white arrow).

A)
B)


Figure 3: Codman triangle. (a) Diagram shows elevated periosteum (arrow) forming an angle with the cortex. (b) Lateral radiograph in patient with osteosarcoma shows the elevated periosteum forming Codman triangle (long arrow). Notice the tumor-induced new bone formation (short arrows.)

B)

A)





Figure 4 :Perpendicular periosteal reaction. (a) Diagram shows spiculated, or hair-on-end, periosteal reaction (arrow). (b) Diagram shows radial, or sunburst, periosteal reaction (arrow).(c) Anteroposterior radiograph in patient with osteosarcoma shows marked perpendicular periosteal reaction in proximal portion of femur.

C)

B)

A)
Figure 5 :Multilamellated periosteal reaction. (a) Diagram shows multilamellated, or onionskin, periosteal reaction (arrow). (b) Anteroposterior radiograph in a patient with osteosarcoma shows multilamellated periosteal reaction (arrow) in proximal portion of femur. Note also large surrounding soft-tissue mass.

B)

A)

Figure 6 :Unilamellated periosteal reaction. (a) Diagram shows single layer of reactive periosteum (arrow). (b) Anteroposterior radiograph of the knee in patient with hypertrophic osteoarthropathy shows thick unilamellated periosteal reaction


B)


A)

Figure 7 : Type 1a geographic lesion .


Figure 8 : Type 1b geographic lesion.


Figure 9 : Type 1c geographic lesion.

Figure 10: Type 2 Moth Eaten lesion .

Figure 11 : Type 3 Permeative lesion.
Table 1 : Soap bubble lesions.
Table 2 : Bone tumors sites.
Table 3 : Bone tumors location.
Table 4 : Multiple bone lesions.
Table 5 : Sequestral lesions . Figure 12 : Common location of bone tumors.
Figure 13 :
Table 6 : Moth eaten bone lesions.
Table 7 : Bone tumors and age

Bone tumors radiology

BONE TUMOUR RADIOLOGY
1. Clues by appearance of lesion
2. Clues by location of lesion
3. Clues by type of periosteal reaction
4. Clues by matrix of lesion
5. Clues by density of lesion
6. Clues by number of lesion

1. Clues By Appearance Of Lesion
Patterns of Bone Destruction

1. Geographic

2. Moth-eaten

3. Permeative

Geographic Bone Destruction
Destructive lesion with sharply defined borderImplies a less-aggressive, more slow-growing, benign processNarrow transition zone

Examples:

1. Non-ossifying fibroma

2. Eosinophilic granuloma

NON OSSIFYING FIBROMA
30 to 40% children over two years have one or more lesions.Most common between 8-20 years of ageUsually occur in metaphysis of one (75%) or more (25%) of the tubular bonesMost lesions heal spontaneously by being replaced with normal bone.May undergo pathologic fracture.Do not undergo malignant transformation

NON OSSIFYING FIBROMA - X-ray characteristics:
* Geographic* Lytic* Multilobulated* Metaphyseal* Usually intramedullary* Eccentric* Well-marginated* Sclerotic rim* Endosteal scalloping

Non-ossifying fibroma of tibia

Eosinophilic Granuloma
Solitary, non-neoplastic proliferation of histiocytes.Part of a spectrum of Langerhan's cell histiocytosis, formerly known as histiocytosis X.Localized lesion in bone or lung and occurs most commonly in children aged 5 to 10.EG is found in the diaphysis or metaphysis of long bones in the center of the medullary cavity.The radiologic differential includes Ewing's sarcoma, osteosarcoma, metastases and osteomyelitis.

Eosinophilic granuloma of femur

Moth-eaten Appearance
Areas of destruction with ragged bordersImplies more rapid growth - High probability of malignancyExample:1. Myeloma2. Metastases3. Lymphoma4. Ewing's sarcoma

Multiple myeloma
Multiple myeloma is a malignant tumor of plasma cells that causes widespread osteolytic bone damage.The average patient age is over 50 years old and men are affected twice as often as women.Characterized by irregular lytic defects of different sizes.These lytic areas are often described as "punched out" and have no periosteal reaction.Erosion begins intramedullarly and progresses through the cortex.

Multiple myeloma of humerus with pathological fracture
Permeative Lesion
Ill-defined lesion with multiple "worm-holes"Spreads through marrow spaceWide transition zoneImplies an aggressive malignancy -Round-cell lesionsExamples:1. Lymphoma2. Leukemia3. Ewing's Sarcoma4. Myeloma5. Neuroblastoma6. Osteomyelitis

2. Clues By Location Of Lesion
1. In the transverse plane:

a) Central - Enchondroma

b) Eccentric -GCT, osteosarcoma, chondromyxoid fibroma

c) Cortical - Non-ossifying fibroma, osteoid osteoma

d) Parosteal - Parosteal osteosarcoma, osteochondroma

2. In the longitudinal plane:

a) Epiphyseal - GCT, chondroblastoma

b) Metaphyseal - Osteomyelitis, osteosarcoma

c) Diaphyseal - Round cell lesions, ABC, enchondroma

Osteoid osteoma
Osteoid Osteoma is a benign bone lesion with a nidus of less than 2 cm surrounded by a zone of reactive bone.Osteoid osteoma has a distinct clinical picture of dull pain that is worse at night and disappears within 20 to 30 minutes of treatment with non-steroidal anti-inflammatory medication.4 diagnostic features include

(1) a sharp round or oval lesion

(2) less than 2 cm in diameter,

(3) has a homogeneous dense center

(4) a 1-2 mm peripheral radiolucent zone.

Osteoid osteoma of transverse process of vertebra

Osteoid osteoma of fibula

Characteristic Location
Simple bone cyst - Proximal humerus

Chondroblastoma - Epiphyses

Giant Cell tumor - Epiphyses

Adamantinoma - Tibia

Chordoma -Sacrum

Osteoblastoma - Posterior element of spine

Parosteal osteosarcoma - Distal femur

Periosteal osteosarcoma - Tibia

Chondrosarcoma - Pelvis
SIMPLE BONE CYST
Solitary cystic lesion over the proximal humerus.Multiple septations.Thinned out cortex.Sclerotic border with narrow zone of transition signifies a benign process.Note: abscence of periosteal reaction differentiates it from aneurysmal bone cyst. (Find out more in my lens on lytic bone lesion).

Solitary bone cyst of femur

CHONDROBLASTOMA
Chondroblastomas are radiolucent lesions that typically occupy the epiphysis (or apophysis) of long bones.They tend to be small (<>

Chondroblastoma of distal femur

chondroplastoma of femur

GIANT CELL TUMOUR
X Ray finding:Solitary expansile lytic lesionMultiple septation (soap bubble appearance)No reactive sclerosisMetaphyseal regionAdjacent to epiphyseal lineJusta-articular if epiphyseal plate is fused

Giant Cell Tumour
Characteristic X Ray finding:Solitary expansile lytic lesionMultiple septation (soap bubble appearance)No reactive sclerosisMetaphyseal regionAdjacent to epiphyseal lineJusta-articular if epiphyseal plate is fused

Giant cell tumour of distal radius
ADAMANTINOMA - TIBIA
Adamantinoma is a locally aggressive osteolytic tumor that is found 90% of the time in the diaphysis of the tibia with the remaining lesions found in the fibula and long tubular bones.Adamantinoma appears as an eccentric, well-circumscribed, and lytic lesion on plain x-ray.The lesion usually has several lytic defects separated by sclerotic bone.There is cortical thinning but little periosteal reaction.
3. Clues By Type Of Periosteal Reaction
Benign - None or Solid periosteal reactionMore aggressive or malignant1. Lamellated or onion-skinning2. Sunburst3. Codman's triangle(More explanation in my lens on Periosteal Reaction)
4. Clues By Matrix Of Lesion
1. Ossification (Osteoblastic process) - Well organized ossified mass with fluffy, cotton-like or cloud-like densities. Eg. Osteosarcoma.2. Calcification (Cartilaginous process)- Unorganized calcified matrix which is comma-shaped, punctate, annular or popcorn-like. Eg. Enchondroma, Chondrosarcoma, Chondromyxoid fibroma.
OSTEOSARCOMA
Well organized mass signifying osteoblastic process.Sunburst periosteal reaction and soft tissue mass signifies an aggressive and rapidly growing tumour. Osteosarcoma of distal femur

CHONDROSARCOMA
Calcified matrix (unorganized) signifies cartilaginous tumour.The wide zone of transition and cortical break without periosteal reaction signifies a rapidly growing and aggressive type of tumour

Chondrosarcoma of left ilium. Note the extensive calcification.

5. Clues By Density Of Lesion
1. Sclerotic Cortical lesions- Osteoid osteoma- Brodie's abscess- Stress fracture

2. Lytic lesions in children- Eosinophilic granuloma- Neuroblastoma- Leukemia

3. Lytic lesions in adult- Metastatic lesions (Lung, Kidney, Thyroid)- Multiple myeloma- Primary bone tumor

4. Blastic lesion in children- Medulloblastoma- Lymphoma

5. Blastic lesion in adult- Metastatic disease (Breast, Prostate)- Lymphoma- Paget's disease
6. Clues by number of lesion
Multiple lesion: More often benignMalignancies with multiple lesions- Metastatic disease- Multiple myeloma- Lymphoma

Reference : Squido.com