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032. Blount disease

visual-inline rebuild2 extracted figuresspeaker notes XML105 study lines8 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

Blounts disease

•Clinical photo showing bilateral genu varum
•Asymmetrical on both sides
•No scars, some internal rotation/ intoeing of left LL (pathognomonic for blounts)
•Likely pathological
•Can be physiological depending on AGE (Salenius curve <2 varus can be physiological)
•Causes
•Physiological, developmental, congenital (dysplasia)
•Inflammatory, metabolic, neuromuscular
•Infection, trauma, tumour
•Bilateral: metabolic, neoplastic, neuromuscular, dysplasia, developmental (DDNNM)
•Unilateral: infection, tumor (HME, Focal fibrocartilagenous dysplasia), trauma, Blount’s, iatrogenic, tibial hemimelia

History

•Onset, progression, other deformities
•Look for causes: Hx suggesting trauma, infection, tumour, Risk factors for rickets: diet

Risk factors for Blounts: early walking, obesity

Examination

Clinical photograph - Blount disease clinical photograph
Fig 1. Clinical photograph - Blount disease clinical photographtop left
•Look for causes: rickets (caput quadratum, ricketic rosary, Harrison sulcus, catback kyphosis, short stature), Dysmorphic features, CP
•Screen: Height; Body; proportion; Symmetry
•Gait: any varus thrusting
•LLD
•Check ROM, collaterals
•Measure TFA, intermalleolar distance
•Rotational profile

Systems examination: hip, spine and feet

•*Cover up test
•Normal: valgus
•Blounts: neutral / varus (indicate varus alignment at proximal tibia or knee)

XR + scannogram

Radiograph / imaging - Blount disease radiograph
Fig 2. Radiograph / imaging - Blount disease radiographtop centre
•TFA, LDFA, MPTA
•Mechanical axis deviation (zoning)
•Physeal abnormalities
•Medial slope angle (angle between medial and lateral physis)
•Drennan angle (metaphyseal diaphyseal angle)
•LLD if any
•Compensatory distal femoral valgus
•Tibial-femoral subluxation

XR features of Blounts: (5)

•Varus angulation at epiphyseal – metaphyseal junction
•Widened and irregular medial physis
•Medially sloped epiphysis
•Beaking of medial metaphysis
•Lateral subluxation of tibia

Langenskiold classification (age and XR findings)

•Beak, wedge, step, enlarge/fill, double, fused
•Bloods for CaPO4, Vit D, PTH ALP
•MRI to assess physeal bar
•+/- CT see rotation
•Aim of treatment: restore mechanical axis to unload medial physis and prevent further progression (Heuter Volkman law)

Problem list in Blount’s disease

•Varus angular deformity
•Medial physeal bar/osteochondrosis
•Depressed joint surface
•Tibial internal torsional deformity

FOR INFANTILE BLOUNTS:

•Principle: depends on patient’s age and severity
•Age cut off 4 yo
•Severity either by Langenskiold stage (III,IV, V, VI) or the Drennan angle (<9 likely physiological, >11 Blounts, >16 need OT)
•Clinical: varus thrust

OT indication:

•>4
•<4yo stage not I/II
•Drennan angle >16
Type / groupDefinition / note
III brace
•KAFO with genu varus strap – provides valgus force in conjunction with a medial upright, with droplocks to increase corrective force during weight bearing
•FU with XR to look of medial physis reconstitution
•If failed to response in 1 year with progression → surgery
•III or above – brace likely not successful, gold standard:

Proximal tibial valgus osteotomy aiming for overcorrection

•+/- Physeal bar excision
•Hemiepiphysiodesis
•Hemiplateau elevation
•Correct IR

Other treatment options:

•Guided growth, with tension band plate and screws
•Possible in earlier stages

FOR ADOLESCENT FORM OF BLOUNTS:

•Less deformity, unilateral, africoamerican descent
•Tx of adolescent form Blount’s (onset > 10yo) is different, which solely depends on the varus angle >10 deg.
•Use CT/MRI to look if the physis is closed or not
•Physis open: lateral tibial epiphysiodesis (either permanent or temporary)
•Physis closed: osteotomy w/out any overcorrection either by a HTO or EF/Ilizarov method/ TSF+/- prophylactic fasciotomy

What is Blount’s disease?

•Dyschondrosis of medial proximal tibial physis leading to progressive pathological genu varum centred at the tibia
•Related to mechanical overload in genetically susceptible individuals
•Excessive medial pressure produces an osteochondrosis of the medial proximal tibial physis and epiphysis +/- progress to physeal bar
•(Heuter Volkman’s law: increased stress = less growth in physis)

Pathophysiology explained by HV principle

•Increase loading to proximal tibial PM physis, growth suppression and irreversible osteochondrosis + bone bridging at medial proximal tibial physis. Also marked metaphyseal fragmentation and resultant progressive tibial vara.
•Vs physiological varus
•Progressive
•More abrupt (Drennan angle >11)
•Physeal abnormality
•Asymmetrical flaring

Risk factors for recurrence

•Age > 5
•Body weight > 95 percentile
•Medial physeal slope > 60 degree
•Langenskiöld stage IV or above
•Drawback of Langenskiold staging
•All stages can occur earlier than described age
•Stage II and III could progress to VI despite OT (i.e. OT does not change the natural history)
•Single osteotomy gives good results only in <4 yo but not <8 yo
•Only include white population instead of more severe Afro-American population

Direct Q&A

Q1 What history should be elicited for Blount disease?

Onset, progression, other deformities

•Look for causes: Hx suggesting trauma, infection, tumour, Risk factors for rickets: diet
Q2 What examination findings should be assessed in Blount disease?
•Look for causes: rickets (caput quadratum, ricketic rosary, Harrison sulcus, catback kyphosis, short stature), Dysmorphic features, CP
•Screen: Height; Body; proportion; Symmetry
•Gait: any varus thrusting
•LLD
•Check ROM, collaterals
•Measure TFA, intermalleolar distance
•Rotational profile
Q3 What are the radiographic findings for Blount disease?

TFA, LDFA, MPTA

•Mechanical axis deviation (zoning)
•Physeal abnormalities
•Medial slope angle (angle between medial and lateral physis)
•Drennan angle (metaphyseal diaphyseal angle)
•LLD if any
•Compensatory distal femoral valgus
•Tibial-femoral subluxation
Q4 What are the indications listed for Blount disease?
•>4
•<4yo stage not I/II
•Drennan angle >16
•I-II brace
•KAFO with genu varus strap – provides valgus force in conjunction with a medial upright, with droplocks to increase corrective force during weight bearing
•FU with XR to look of medial physis reconstitution
•If failed to response in 1 year with progression → surgery
•III or above – brace likely not successful, gold standard:
Q5 What operative steps, indications, and risks are listed for Proximal tibial valgus osteotomy aiming for overcorrection?

+/- Physeal bar excision

•Hemiepiphysiodesis
•Hemiplateau elevation
•Correct IR
Q6 What is Blount’s disease?
•Dyschondrosis of medial proximal tibial physis leading to progressive pathological genu varum centred at the tibia
•Related to mechanical overload in genetically susceptible individuals
•Excessive medial pressure produces an osteochondrosis of the medial proximal tibial physis and epiphysis +/- progress to physeal bar
•(Heuter Volkman’s law: increased stress = less growth in physis)
Q7 What pathophysiology is described for Blount disease?
•Increase loading to proximal tibial PM physis, growth suppression and irreversible osteochondrosis + bone bridging at medial proximal tibial physis. Also marked metaphyseal fragmentation and resultant progressive tibial vara.
•Vs physiological varus
•Progressive
•More abrupt (Drennan angle >11)
•Physeal abnormality
•Asymmetrical flaring
Q8 What risk factors are listed for Blount disease?
•Age > 5
•Body weight > 95 percentile
•Medial physeal slope > 60 degree
•Langenskiöld stage IV or above

Drawback of Langenskiold staging

•All stages can occur earlier than described age
•Stage II and III could progress to VI despite OT (i.e. OT does not change the natural history)
•Single osteotomy gives good results only in <4 yo but not <8 yo
•Only include white population instead of more severe Afro-American population

Raw speaker-note hierarchy audit

#lvlmarLindentlogicaloriginal note line
10NoneNone0Blounts disease
20NoneNone0Clinical photo showing bilateral genu varum
30NoneNone0Asymmetrical on both sides
40NoneNone0No scars, some internal rotation/ intoeing of left LL (pathognomonic for blounts)
50NoneNone0Likely pathological
60NoneNone0Can be physiological depending on AGE (Salenius curve <2 varus can be physiological)
70NoneNone0Causes
80171450-1714501Physiological, developmental, congenital (dysplasia)
90171450-1714501Inflammatory, metabolic, neuromuscular
100171450-1714501Infection, trauma, tumour
110NoneNone0Bilateral: metabolic, neoplastic, neuromuscular, dysplasia, developmental (DDNNM)
120NoneNone0Unilateral: infection, tumor (HME, Focal fibrocartilagenous dysplasia), trauma, Blount’s, iatrogenic, tibial hemimelia
130NoneNone0Hx:
140NoneNone0Onset, progression, other deformities
150000Look for causes: Hx suggesting trauma, infection, tumour, Risk factors for rickets: diet
160NoneNone0Risk factors for Blounts: early walking, obesity
170NoneNone0PE:
180000Look for causes: rickets (caput quadratum, ricketic rosary, Harrison sulcus, catback kyphosis, short stature), Dysmorphic features, CP
190NoneNone0Screen: Height; Body; proportion; Symmetry
200NoneNone0Gait: any varus thrusting
210000LLD
220NoneNone0Check ROM, collaterals
230NoneNone0Measure TFA, intermalleolar distance
240000Rotational profile
250NoneNone0Systems examination: hip, spine and feet
260000*Cover up test
27145720001Normal: valgus
28145720001Blounts: neutral / varus (indicate varus alignment at proximal tibia or knee)
290NoneNone0XR + scannogram
300171450-1714501TFA, LDFA, MPTA
310171450-1714501Mechanical axis deviation (zoning)
320171450-1714501Physeal abnormalities
330171450-1714501Medial slope angle (angle between medial and lateral physis)
340171450-1714501Drennan angle (metaphyseal diaphyseal angle)
350171450-1714501LLD if any
360171450-1714501Compensatory distal femoral valgus
370171450-1714501Tibial-femoral subluxation
380000XR features of Blounts: (5)
390228600-2286001Varus angulation at epiphyseal – metaphyseal junction
400228600-2286001Widened and irregular medial physis
410228600-2286001Medially sloped epiphysis
420228600-2286001Beaking of medial metaphysis
430228600-2286001Lateral subluxation of tibia
440NoneNone0Langenskiold classification (age and XR findings)
451NoneNone1Beak, wedge, step, enlarge/fill, double, fused
460NoneNone0Bloods for CaPO4, Vit D, PTH ALP
470NoneNone0MRI to assess physeal bar
480000+/- CT see rotation
490NoneNone0Aim of treatment: restore mechanical axis to unload medial physis and prevent further progression (Heuter Volkman law)
500NoneNone0Problem list in Blount’s disease
510228600-2286001Varus angular deformity
520228600-2286001Medial physeal bar/osteochondrosis
530228600-2286001Depressed joint surface
540228600-2286001Tibial internal torsional deformity
550NoneNone0FOR INFANTILE BLOUNTS:
560NoneNone0Principle: depends on patient’s age and severity
570NoneNone0Age cut off 4 yo
580NoneNone0Severity either by Langenskiold stage (III,IV, V, VI) or the Drennan angle (<9 likely physiological, >11 Blounts, >16 need OT)
590NoneNone0Clinical: varus thrust
600000OT indication:
610171450-1714501>4
620171450-1714501<4yo stage not I/II
630171450-1714501Drennan angle >16
640NoneNone0I-II brace
650NoneNone0KAFO with genu varus strap – provides valgus force in conjunction with a medial upright, with droplocks to increase corrective force during weight bearing
660NoneNone0FU with XR to look of medial physis reconstitution
670NoneNone0If failed to response in 1 year with progression → surgery
680NoneNone0III or above – brace likely not successful, gold standard:
690228600-2286001Proximal tibial valgus osteotomy aiming for overcorrection
700228600-2286001+/- Physeal bar excision
710228600-2286001Hemiepiphysiodesis
720228600-2286001Hemiplateau elevation
730228600-2286001Correct IR
740NoneNone0Other treatment options:
750NoneNone0Guided growth, with tension band plate and screws
760NoneNone0Possible in earlier stages
770NoneNone0FOR ADOLESCENT FORM OF BLOUNTS:
780NoneNone0Less deformity, unilateral, africoamerican descent
790NoneNone0Tx of adolescent form Blount’s (onset > 10yo) is different, which solely depends on the varus angle >10 deg.
800NoneNone0Use CT/MRI to look if the physis is closed or not
810171450-1714501Physis open: lateral tibial epiphysiodesis (either permanent or temporary)
820171450-1714501Physis closed: osteotomy w/out any overcorrection either by a HTO or EF/Ilizarov method/ TSF+/- prophylactic fasciotomy
830NoneNone0=========================================
840NoneNone0What is Blount’s disease?
850NoneNone0Dyschondrosis of medial proximal tibial physis leading to progressive pathological genu varum centred at the tibia
860NoneNone0Related to mechanical overload in genetically susceptible individuals
870NoneNone0Excessive medial pressure produces an osteochondrosis of the medial proximal tibial physis and epiphysis +/- progress to physeal bar
880NoneNone0(Heuter Volkman’s law: increased stress = less growth in physis)
890NoneNone0Pathophysiology explained by HV principle
900171450-1714501Increase loading to proximal tibial PM physis, growth suppression and irreversible osteochondrosis + bone bridging at medial proximal tibial physis. Also marked metaphyseal fragmentation and resultant progressive tibial vara.
910171450-1714501Vs physiological varus
921628650-1714502Progressive
931628650-1714502More abrupt (Drennan angle >11)
941628650-1714502Physeal abnormality
951628650-1714502Asymmetrical flaring
960NoneNone0Risk factors for recurrence
971NoneNone1Age > 5
98145720001Body weight > 95 percentile
991NoneNone1Medial physeal slope > 60 degree
1001NoneNone1Langerskiold stage IV or above
1010000Drawback of Langenskiold staging
1020228600-2286001All stages can occur earlier than described age
1030228600-2286001Stage II and III could progress to VI despite OT (i.e. OT does not change the natural history)
1040228600-2286001Single osteotomy gives good results only in <4 yo but not <8 yo
1050228600-2286001Only include white population instead of more severe Afro-American population

Improved semantic hierarchy used for the study notes

#semantic levelsection?rewritten line
10Blounts disease
21Clinical photo showing bilateral genu varum
31Asymmetrical on both sides
41No scars, some internal rotation/ intoeing of left LL (pathognomonic for blounts)
51Likely pathological
61Can be physiological depending on AGE (Salenius curve <2 varus can be physiological)
71Causes
81Physiological, developmental, congenital (dysplasia)
91Inflammatory, metabolic, neuromuscular
101Infection, trauma, tumour
111Bilateral: metabolic, neoplastic, neuromuscular, dysplasia, developmental (DDNNM)
121Unilateral: infection, tumor (HME, Focal fibrocartilagenous dysplasia), trauma, Blount’s, iatrogenic, tibial hemimelia
130yesHistory
141Onset, progression, other deformities
151Look for causes: Hx suggesting trauma, infection, tumour, Risk factors for rickets: diet
160yesRisk factors for Blounts: early walking, obesity
170yesExamination
181Look for causes: rickets (caput quadratum, ricketic rosary, Harrison sulcus, catback kyphosis, short stature), Dysmorphic features, CP
191Screen: Height; Body; proportion; Symmetry
201Gait: any varus thrusting
211LLD
221Check ROM, collaterals
231Measure TFA, intermalleolar distance
241Rotational profile
250yesSystems examination: hip, spine and feet
261*Cover up test
271Normal: valgus
281Blounts: neutral / varus (indicate varus alignment at proximal tibia or knee)
290yesXR + scannogram
301TFA, LDFA, MPTA
311Mechanical axis deviation (zoning)
321Physeal abnormalities
331Medial slope angle (angle between medial and lateral physis)
341Drennan angle (metaphyseal diaphyseal angle)
351LLD if any
361Compensatory distal femoral valgus
371Tibial-femoral subluxation
380yesXR features of Blounts: (5)
391Varus angulation at epiphyseal – metaphyseal junction
401Widened and irregular medial physis
411Medially sloped epiphysis
421Beaking of medial metaphysis
431Lateral subluxation of tibia
440yesLangenskiold classification (age and XR findings)
451Beak, wedge, step, enlarge/fill, double, fused
461Bloods for CaPO4, Vit D, PTH ALP
471MRI to assess physeal bar
481+/- CT see rotation
491Aim of treatment: restore mechanical axis to unload medial physis and prevent further progression (Heuter Volkman law)
500yesProblem list in Blount’s disease
511Varus angular deformity
521Medial physeal bar/osteochondrosis
531Depressed joint surface
541Tibial internal torsional deformity
550yesFOR INFANTILE BLOUNTS:
561Principle: depends on patient’s age and severity
571Age cut off 4 yo
581Severity either by Langenskiold stage (III,IV, V, VI) or the Drennan angle (<9 likely physiological, >11 Blounts, >16 need OT)
591Clinical: varus thrust
600yesOT indication:
611>4
621<4yo stage not I/II
631Drennan angle >16
641I-II brace
651KAFO with genu varus strap – provides valgus force in conjunction with a medial upright, with droplocks to increase corrective force during weight bearing
661FU with XR to look of medial physis reconstitution
671If failed to response in 1 year with progression → surgery
681III or above – brace likely not successful, gold standard:
690yesProximal tibial valgus osteotomy aiming for overcorrection
701+/- Physeal bar excision
711Hemiepiphysiodesis
721Hemiplateau elevation
731Correct IR
740yesOther treatment options:
751Guided growth, with tension band plate and screws
761Possible in earlier stages
770yesFOR ADOLESCENT FORM OF BLOUNTS:
781Less deformity, unilateral, africoamerican descent
791Tx of adolescent form Blount’s (onset > 10yo) is different, which solely depends on the varus angle >10 deg.
801Use CT/MRI to look if the physis is closed or not
811Physis open: lateral tibial epiphysiodesis (either permanent or temporary)
821Physis closed: osteotomy w/out any overcorrection either by a HTO or EF/Ilizarov method/ TSF+/- prophylactic fasciotomy
830——
840yesWhat is Blount’s disease?
851Dyschondrosis of medial proximal tibial physis leading to progressive pathological genu varum centred at the tibia
861Related to mechanical overload in genetically susceptible individuals
871Excessive medial pressure produces an osteochondrosis of the medial proximal tibial physis and epiphysis +/- progress to physeal bar
881(Heuter Volkman’s law: increased stress = less growth in physis)
890yesPathophysiology explained by HV principle
901Increase loading to proximal tibial PM physis, growth suppression and irreversible osteochondrosis + bone bridging at medial proximal tibial physis. Also marked metaphyseal fragmentation and resultant progressive tibial vara.
911Vs physiological varus
922Progressive
932More abrupt (Drennan angle >11)
942Physeal abnormality
952Asymmetrical flaring
960yesRisk factors for recurrence
971Age > 5
981Body weight > 95 percentile
991Medial physeal slope > 60 degree
1001Langenskiöld stage IV or above
1011Drawback of Langenskiold staging
1021All stages can occur earlier than described age
1031Stage II and III could progress to VI despite OT (i.e. OT does not change the natural history)
1041Single osteotomy gives good results only in <4 yo but not <8 yo
1051Only include white population instead of more severe Afro-American population
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