FRCS Paediatric Ortho — improved notes
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008. DDH arthrogram and Ramsey safe zone

visual-inline rebuild1 extracted figuresspeaker notes XML41 study lines4 Q&A

Individual slide images have been cropped from the rendered slide and inserted beside the matching note section. The full slide remains below only for layout/audit.

Clean FRCS notes with inline figures

Use of arthrogram

Arthrogram image - arthrogram
Fig 1. Arthrogram image - arthrogramtop left
•Assess congruency of reduction
•Define obstacles to reduction
•Delineate optimal position for immobilization

How to perform?

•GA, supine

Xray control

•CR first

Medial subadductor approach, aiming for ipsilateral scapula

•22gauge needle Injection NS and look for back flow
•Inject small amount of dye to confirm position
•Image at dislocated and reduced position
•Risk: damage to cartilage, injection into growth plate. Vessel injury
•Adductor tenotomy if post reduction narrow safe zone (increase abduction safe zone)
•Psoas tendon release if the hip tend to sublux as the hip was extended below 90 degrees (increase extension safe zone)

Structure that obscure reduction

•intra-capsular 2+2+2
•Superior
•Inverted labrum
•Neolimbus
•Central
•Pulvinar
•Ligamentum teres
•Inferior
•Transverse acetabular ligament
•Constricted capsule
•Extra-capsular
•Tight Iliopsoas
•Tight Adductor
•Look for medial pooling >7mm

What is safe zone of Ramsey?

•Cone of motion that the hip spica allows the hip to move without dislocating
•Defined as the difference (in degrees) between the angle of maximal hip abduction (cause AVN) and the hip adduction at which the femoral head dislocates with the hip examined in 90 degree flexion
•Safety cone = a cone-shaped zone that is within 15-20 degree of the maximal range of motion and dislocation range (satisfactory if at least 40 degree)
•Two important factors to consider
•The average movement of the hip in the hip spica is 15deg, so it is important to keep the hip away from the line of dislocation by about 20 degree
•The risk of AVN increases with the hip put at max ROM so it is safe to be 20 degree inside the maximum ROM
•If successful reduction with <7mm medial pooling
•Check range with stable reduction
•If congruent reduction, large zone of safety (safety zone larger than 40°) → hip spica cast, take axial cut CT to r/o posterior dislocation
•Otherwise→ open reduction

Direct Q&A

Q1 What diagnostic or radiographic findings support DDH arthrogram and Ramsey safe zone?

Use of arthrogram

•Assess congruency of reduction
•Define obstacles to reduction
•Delineate optimal position for immobilization

How to perform?

•GA, supine

Xray control

•CR first

Medial subadductor approach, aiming for ipsilateral scapula

•22gauge needle Injection NS and look for back flow
Q2 What operative steps, indications, and risks are listed for Medial subadductor approach, aiming for ipsilateral scapula?

22gauge needle Injection NS and look for back flow

•Inject small amount of dye to confirm position
•Image at dislocated and reduced position
•Risk: damage to cartilage, injection into growth plate. Vessel injury

Adductor tenotomy if post reduction narrow safe zone (increase abduction safe zone)

•Psoas tendon release if the hip tend to sublux as the hip was extended below 90 degrees (increase extension safe zone)
Q3 What is safe zone of Ramsey?
•Cone of motion that the hip spica allows the hip to move without dislocating
•Defined as the difference (in degrees) between the angle of maximal hip abduction (cause AVN) and the hip adduction at which the femoral head dislocates with the hip examined in 90 degree flexion
•Safety cone = a cone-shaped zone that is within 15-20 degree of the maximal range of motion and dislocation range (satisfactory if at least 40 degree)
•Two important factors to consider
•The average movement of the hip in the hip spica is 15deg, so it is important to keep the hip away from the line of dislocation by about 20 degree
•The risk of AVN increases with the hip put at max ROM so it is safe to be 20 degree inside the maximum ROM
•If successful reduction with <7mm medial pooling
•Check range with stable reduction
•If congruent reduction, large zone of safety (safety zone larger than 40°) → hip spica cast, take axial cut CT to r/o posterior dislocation
•Otherwise→ open reduction
Q4 How is DDH arthrogram and Ramsey safe zone managed?
•CR first

Medial subadductor approach, aiming for ipsilateral scapula

•22gauge needle Injection NS and look for back flow
•Inject small amount of dye to confirm position
•Image at dislocated and reduced position
•Risk: damage to cartilage, injection into growth plate. Vessel injury
•Adductor tenotomy if post reduction narrow safe zone (increase abduction safe zone)
•Psoas tendon release if the hip tend to sublux as the hip was extended below 90 degrees (increase extension safe zone)

Structure that obscure reduction

•intra-capsular 2+2+2
•Superior
•Inverted labrum
•Neolimbus
•Central
•Pulvinar
•Ligamentum teres

Raw speaker-note hierarchy audit

#lvlmarLindentlogicaloriginal note line
10NoneNone0Use of arthrogram
20171450-1714501Assess congruency of reduction
30171450-1714501Define obstacles to reduction
40171450-1714501Delineate optimal position for immobilization
50000How to perform?
60171450-1714501GA, supine
70171450-1714501Xray control
80171450-1714501CR first
90171450-1714501Medial subadductor approach, aiming for ipsilateral scapula
100171450-171450122gauge needle Injection NS and look for back flow
110171450-1714501Inject small amount of dye to confirm position
120171450-1714501Image at dislocated and reduced position
130171450-1714501Risk: damage to cartilage, injection into growth plate. Vessel injury
140000Adductor tenotomy if post reduction narrow safe zone (increase abduction safe zone)
150000Psoas tendon release if the hip tend to sublux as the hip was extended below 90 degrees (increase extension safe zone)
160NoneNone0Structure that obscure reduction
170171450-1714501intra-capsular 2+2+2
181628650-1714502Superior
1921085850-1714503Inverted labrum
2021085850-1714503Neolimbus
211628650-1714502Central
2221085850-1714503Pulvinar
2321085850-1714503Ligamentum teres
241628650-1714502Inferior
2521085850-1714503Transverse acetabular ligament
2621085850-1714503Constricted capsule
270171450-1714501Extra-capsular
281628650-1714502Tight Iliopsoas
291628650-1714502Tight Adductor
300000Look for medial pooling >7mm
310000What is safe zone of Ramsey?
320000Cone of motion that the hip spica allows the hip to move without dislocating
330NoneNone0Defined as the difference (in degrees) between the angle of maximal hip abduction (cause AVN) and the hip adduction at which the femoral head dislocates with the hip examined in 90 degree flexion
340NoneNone0Safety cone = a cone-shaped zone that is within 15-20 degree of the maximal range of motion and dislocation range (satisfactory if at least 40 degree)
350000Two important factors to consider
360171450-1714501The average movement of the hip in the hip spica is 15deg, so it is important to keep the hip away from the line of dislocation by about 20 degree
370171450-1714501The risk of AVN increases with the hip put at max ROM so it is safe to be 20 degree inside the maximum ROM
380NoneNone0If successful reduction with <7mm medial pooling
390NoneNone0Check range with stable reduction
400NoneNone0If congruent reduction, large zone of safety (safety zone larger than 40°) → hip spica cast, take axial cut CT to r/o posterior dislocation
410NoneNone0Otherwise→ open reduction

Improved semantic hierarchy used for the study notes

#semantic levelsection?rewritten line
10Use of arthrogram
21Assess congruency of reduction
31Define obstacles to reduction
41Delineate optimal position for immobilization
50yesHow to perform?
61GA, supine
70yesXray control
81CR first
90yesMedial subadductor approach, aiming for ipsilateral scapula
10122gauge needle Injection NS and look for back flow
111Inject small amount of dye to confirm position
121Image at dislocated and reduced position
131Risk: damage to cartilage, injection into growth plate. Vessel injury
141Adductor tenotomy if post reduction narrow safe zone (increase abduction safe zone)
151Psoas tendon release if the hip tend to sublux as the hip was extended below 90 degrees (increase extension safe zone)
160yesStructure that obscure reduction
171intra-capsular 2+2+2
182Superior
193Inverted labrum
203Neolimbus
212Central
223Pulvinar
233Ligamentum teres
242Inferior
253Transverse acetabular ligament
263Constricted capsule
271Extra-capsular
282Tight Iliopsoas
292Tight Adductor
301Look for medial pooling >7mm
310yesWhat is safe zone of Ramsey?
321Cone of motion that the hip spica allows the hip to move without dislocating
331Defined as the difference (in degrees) between the angle of maximal hip abduction (cause AVN) and the hip adduction at which the femoral head dislocates with the hip examined in 90 degree flexion
341Safety cone = a cone-shaped zone that is within 15-20 degree of the maximal range of motion and dislocation range (satisfactory if at least 40 degree)
351Two important factors to consider
361The average movement of the hip in the hip spica is 15deg, so it is important to keep the hip away from the line of dislocation by about 20 degree
371The risk of AVN increases with the hip put at max ROM so it is safe to be 20 degree inside the maximum ROM
381If successful reduction with <7mm medial pooling
391Check range with stable reduction
401If congruent reduction, large zone of safety (safety zone larger than 40°) → hip spica cast, take axial cut CT to r/o posterior dislocation
411Otherwise→ open reduction
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