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Correction of Lower Limb Deformity
Dr. J. Rawat
Source
DiagnosticDiagnostic
Radiographs of the lower limbs:Long filmsFrontal plane (AP view)(Patella Forward) Sagittal plane (Lateral view)
In case of Severe Rotational DeformityHip Forward view(AP Femur)
DiagnosticDiagnostic
DiagnosticDiagnostic
Patient with LLD
Square the pelvis
DiagnosticDiagnosticAP view standing radiographs
DiagnosticDiagnostic
Long LAT view radiograph
Deformity of the lower limb (Frontal Plane)
MMechanical AAxis DDeviation (MAD)
Malalignment
AXIS (mechanical + anatomical)
• Mechanical Axis of the Lower Limb.
• Mechanical Axis of Femur.• Anatomical Axis of Femur.
(7degrees to AA)• Mechanical Axis =
Anatomical Axis of Tibia.• If 1 limb is normal used as
guide for correction.
MAT (Malalignment Test)MAT (Malalignment Test)
Analyzing of
the cause or
the locationof
the malalignment !
MAT (Malalignment Test)MAT (Malalignment Test)
Step:1Measurement of the MAD
Mechanical Axis Deviation
=
>15 mm medial< 1 mm lateral
Mechanical Axis
Source of MAD (Varus)
• Varus: Bony Malalignment Tibia vara (MPTA<85) Femoral Valgus Deformity(LTFA >90) Combination• Joint Surface Malalignment Depressed or deficient Lateral Tibial Plateau Depressed or deficient Lateral Femoral Condyl• Ligamentocapsular (interosseous) Malalignment Lateral Joint Laxity Medial Tibial Subluxation
Source of MAD (Valgus)
• Varus: Bony Malalignment Tibia valga (MPTA>90) Femoral Varus Deformity(LTFA <85) Combination• Joint Surface Malalignment Depressed or deficient medial Tibial Plateau Depressed or deficient medial Femoral Condyl• Ligamentocapsular (interosseous) Malalignment Medial Joint Laxity Lateral Tibial Subluxation
Source of MAD (Valgus)
MAT (Malalignment Test)MAT (Malalignment Test)
Step: 2. Measurement of the LDFALDFA= llateral ddistal ffemur aangleusing the mechanical and anatomical axises.
MAT (Malalignment Test)MAT (Malalignment Test)(Step 2 Contd.)
Measurement of the LDFALDFA= llateral ddistal ffemur aangle
< 85° LDFA = Valgus deviation> 90° LDFA = Varus deviation
of the femur
MAT (Malalignment Test)MAT (Malalignment Test)
Step: 3. Measurement of the MPTAMPTA
= mmedial pproximal ttibia aangle
MAT (Malalignment Test)MAT (Malalignment Test)
Step 3 contd.Measurement of the MPTAMPTA
= mmedial pproximal ttibia aangle
> 90°MPTA = Valgus deviation< 90°MPTA = Varus deviation
of the tibia
MAT (Malalignment Test)MAT (Malalignment Test)
Step: 4. Measurement of the JLCAJLCA
= jjoint lline ccovergence aangleNormal= 0-2 degrees
Medial JLCA >2°: - lateral ligament hyperlaxity - medial loss of cartilageLateral JLCA >2°: - medial ligament hyperlaxity - lateral loss of cartilage
MAT ( Malalignment Test)MAT ( Malalignment Test)
•Malorientation of / around knee will change the MADand MAT will be abnormal.
•MalorientationMalorientation in the hiphip and ankle will cause no/minimalankle will cause no/minimalchange in the MADand MAT may be normal.change in the MADand MAT may be normal.
Malorientation-Test (MOT)Malorientation-Test (MOT)for ankle and hipfor ankle and hip
Malorientation-Test Malorientation-Test (MOT)(MOT)
for for a) ankle and b) hipa) ankle and b) hip
Malorientation-Test = MOTMalorientation-Test = MOT
1. Step:Measurement of the LPFA
= lateral proximal femur angle(mechanical)
Malorientation-Test = MOTMalorientation-Test = MOT
2. Step:Measurement of the MPFA
= medial proximal femur angle(anatomical)
Malorientation-Test = MOTMalorientation-Test = MOT
3. Step:Measurement of the LDTA= lateral distal tibia angle
Sagittal Plane
ANSA = 165 -175AMA= 7degreesMDA(mid diaphysial angle)=10 (Femur)
CORA
•Angulation Correction Axis
•Bisector Line
CORA
• Femur
Osteotomy rule IOsteotomy rule I
When the Osteotomy line, and ACA pass through the CORArealignment occurs without translation and only angulation is required to correct the deformity.
Osteotomy rule IIOsteotomy rule II
When the ACA is through the CORA but the osteotomy is at a different level, the axis will realign by angulation and translation at the osteotomy site.
Corollary to Rule IICorollary to Rule II
If osteotomy passes through a different level than the CORA and the axis of correction(ACA) is on the osteotomy line then Translation Deformity will result.
Osteotomy rule IIIOsteotomy rule III
If there is more than one CORA, complete realignment of Mechanical axis and Anatomical axis requires a separate osteotomies for each CORA with seperate Axis of Correction(ACA) for each CORA.
The level and magnitude of one apex determining the level and magniture of the other apex
Corollary to Rule III
If the Osteotomy is done through the Resolution point CORA rather than true multiple apices, then the mechanical axis and joint orientation will correct with a residual alteration in the Anatomical axis of the bone.(This may be a cosmetic problem.)
Conditions when Osteotomy not done at CORA
• If CORA is at Joint Level
• If CORA is at the Epiphysis in Children.
• Skin and Soft tissue Consideration
Isolated Tibial Diaphysial Deformity
• Step 0-Measure MAD • Step1 Draw Mechanical axis of Femur after
conducting MAT,MOT.• Step2 Draw a line from Center of Ankle
Plafond along Anatomical axis ofDistal Tibia.• Step 3 Find CORA and Angle of Deformity
where this line meets the Extended Mechanical Axis of Femur.
Juxta Articular
Tibial Deformity
with a Normal Femur
Diaphiseal Femoral
Deformity
with Normal Tibia
Juxta Articular Femoral deformity with Normal Tibia
Anatomical Axis Method of Preop Planning for Femur
Conditions where Anatomical Axis used for Femur
• Femoral Head deformed so mechanical axis cant be made.
• Severe Rotational deformity of Femur.
• CORA not corresponding to the apparent deformity
Combined Femoral
And Tibial Deformity
in the Absence of Normal Opposite
Side
Level of Osteotomy
CORA not at Apex of
Apparent Deformity
Order of Deformity Correction
• 1st correct the Angular Deformity
• 2nd correct the Length
• 3rd correct the Rotation after the Angulation is Corrected.
• Finally correct Translation
Effect of Rotation on Pre op Planning.
• Tibia Rotation can be corrected through the CORA determined by Previous Method .
• Can Alter Level of CORA in Femur.
• Ext Rot leads to app shortening and Int Rot to app Lengthening of Femoral Neck
Compensating the Rotation
• Clinically determine the Rotation deformity• Xray with the Hip forward position (Knee
rotated)• Measure Distance from Mid Diaphysial line to
Center of head of Femur.• Compare with same distance in Knee forward
film.• Center of Femur head for mechanical axis
line are shifted Medially or Laterally by the same distance
Sagittal Plane
Correction
Sagittal Plane Deformity
• Malalignment Better tolerated.• Compensated for by Hip,Knee,Ankle Subtalar
and Midfoot.• Associated with late degenerative changes. • Malalignment Test• Malorientation Teat• Correction using Anatomical Axis• Soft tissue component of deformity should be
corrected before osteotomy.
Methods to Correct the Deformity
• Osteotomy and Plating
Single Deformity
Metaphysial Correction• Osteotomy and Nailing
Multi level osteotomy
Diaphysial Correction• Fitbone Lengthening also required• Fixators Ring, Taylor Spatial Frame,Monorail
Example for reverse planningExample for reverse planningas described by Reiner Boungartas described by Reiner Boungart
• 15 yo girl originally from Afghanistan.• Known case of Vit. D resistant rickets
Clinical
• Short stature: Ht = 141.2 cmShort stature: Ht = 141.2 cm Wt 42.5 kg
• Has splayed wrists• Pain in the legs off and on.• No knee pain or instability at present.
Mechanical Axis Deviation (MAD)
Lt = 40mm Medial Rt = 33mm Medial Normal = 8+/- 7 mm medial
Mechanical Axis
Femur: Lt = 20°
Rt = 25°
Tibia: Lt = 20°
Rt = 14°
X-ray MeasurementsX-ray Measurements
mLDFA [85 – 90] Lt = 95 Rt = 97
MPTA [85 – 90]
Lt = 78
Rt = 80
JLCA [0 – 2]
Lt = 2
Rt = 1
Measurements ContdMeasurements Contd
mLPFA [85 – 95] Lt = 102 Rt = 105aMPFA [79-89] Lt = 82 Rt = 70aMNSA [125-135] Lt = 128 Rt = 123
Measurements ContdMeasurements Contd
LDTA
Rt = 90 Lt = 90
[86-92]
Sagittal planeSagittal plane
• ANSAANSA Lt = 165
Rt = 165
Normal = 165-175
• Mid diaphysial Angle (MDA)Mid diaphysial Angle (MDA)
Lt = 15
Rt = 15
Normal = 10
Sagittal planeSagittal plane
PDFA Lt = 80
Rt = 80
Normal = 79-87
Mid diaphysial Angle (MDA)
Lt = 8
Rt = 10
Normal = 0
Sagittal planeSagittal plane
ADTAADTA
Rt = 83 Lt = 84
Normal = 78-82
2. Exact planning of the 2. Exact planning of the deformity correctiondeformity correction- operative planning- operative planning
Lengthening of 4cm at the femur
Translation of 4 mm
„Reverse planning“ – technique described by PD Dr. Baumgart in Bangkok November / 2003
Different planning!
Preoperative Planning-BasicsPreoperative Planning-Basics
• At the end of the preoperative planning for leg lengthening, the mechanical axis pass the center of hip, ankle and knee
• Analyze the bone which has to be corrected and mark the center of angulation (CORA)
• Use the mechanical (= anatomical) axis of the tibia as orientation line for the correction, if there is no Tibia deformity (in the follow exmple-both Tibia and Femur-are deformed)
• Be certain, that the mechanical lateral distal femur angle (mLDFA) is within the physiological range (85°-90°) before you start
Draw a target, vertical linetarget, vertical line on tracing paper representing the new mechanical axis and another line crossing at 87°.
Evaluate the knee joint angle line very precisely and place this line on the crossing line, what this means, that knee joint is now orientated under 87° to the mechanical axis
Reverse Planning- Step1Reverse Planning- Step1
Take over the target line representing the new mechanical axis, place the center of the knee joint on this line and continue the line distally.
Mark the center of rotation of angulation (CORA).
Mark the center of the ankle joint CA on this line in correct position according to the opposite length or to the desirable length.
Reverse Planning TibiaReverse Planning TibiaStep 2aStep 2a
CA
This should be the position of the ankle joint at the final result = CA .
Choose an OT level near to the center of CORA in accordance with the locking performance of the nail and draw a transverse line to identify the level.
Reverse Planning TibiaReverse Planning TibiaStep 2bStep 2b
CA
Take an extra sheet and draw the distal part of the tibia ending within the OT-line.
Draw the anatomical axis and the scaled nail borderline according to the diameter of the planned nail. The nail will always center in the diaphysis and simulate by drawing the bone reaming of the curved cortex.
Lengthen the lines proximally out of the fragment.
Reverse Planning TibiaReverse Planning TibiaStep 3Step 3
Take the extra sheet and place the center of the ankle joint exactly on the dedicated center CA which was found in step 2a so that
1. The entry point of the nail has to be near to the middle of the tibia head not damaging any cartilage
2.the lines of the nail coming out of the distal fragment enter the distal frontplane of the proximal tibia fragment at the OT-level
Reverse Planning – TibiaReverse Planning – TibiaStep 4Step 4
CA
Shift the distal fragment upwards along the anatomical axis, because this will be the the reverse actreverse act of lengthening over a nail.
If the frontal planes of both fragments get into contact, mark the new center of the ankle joint CA´ .
The position of the distal tibia fragment now is the postoperative position which is essential to get the exact position after the complete lengthening as planed.
Reverse Planning TibiaReverse Planning TibiaStep 5Step 5
CA
CA`
• The exact geometrical position (lat. or med. shift)
• The angle of the frontal planes of the proximal + distal fragment
• The position of the entry point of the nail
Reverse Planning TibiaReverse Planning Tibia
Evaluate
All these landmarks must be exactly achieved intraoperatively visually and controlled on thescreen with the Patella in front.
Take over the vertical target line vertical target line (()) of the tibia representing the mechanical axis, place the center of the knee joint and ankle joint on this line and continue the line proximally as the target line.
Reverse Planning Reverse Planning Step 6Step 6
Mark the center of rotation of angulation (CORA).
Mark the center of the hip joint CH´ on this line in correct position according to the opposite length or to the desirable length.
Reverse Planning FemurReverse Planning FemurStep 7aStep 7a
This should be the position of the hip joint at the final result = CH´ .
Choose an OT level near to the center of CORA in accordance with the locking performance of the nail and draw a transverse line to identify the level.
Reverse Planning Reverse Planning Femur- Step 7bFemur- Step 7b
CH
CH´
Take an extra sheet and draw the proximal part of the femur ending with the OT-line.
Draw the anatomical axis and the scaled nail borderline according to the diameter of the planed nail. The nail will always center in the diaphysis. Anatomical variations of the proximal femur such as coxa valga which could be an obstacle for antegrade nailing does not affect your planning for retrograde nailing.
Lengthen the lines distally out of the fragment.
Reverse Planning FemurReverse Planning FemurStep 8Step 8
CH
CH´
Take the extra sheet and place the center of the hip joint (CH) exactly on the dedicated center CH´ which was found in step 7b so that
1. The entry point of the nail has to be in the middle of the condyles allowing the entry of a nail without damaging any
cartilage or cruciate ligament
2.the borderlines of the nail coming out of the proximal fragment enter the proximal frontplane of the distal femur fragment at the OT- level
Reverse Planning Femur Reverse Planning Femur Step 9aStep 9a
CH´
3. The lateral proimal femur angle (LPFA) should be about 90° preventing an overtention or relaxation of the gluteus muscle –both should be examined clinically
4. After final position of the proximal femur fragment, the exitpoint of the nail at the distal femur fragment is defined and the entry point comes out exactly in the middle of the condyles.
Reverse Planning Femur Reverse Planning Femur Step 9bStep 9b
CH´
Shift the proximal fragment downwards along the anatomical axis, because this will be the reverse actthe reverse act of lengthening over a nail.
If the frontal planes of both fragments get into contact, mark the new center of the hip joint CH* .
The position of the proximal femur fragment now is the postoperative position which is essential to get the exact position (=CH´) after the complete lengthening as planed.
Reverse Planning Reverse Planning Femur- Step 10Femur- Step 10
CH´
CH*
Note: Evaluate...Note: Evaluate...- The exact geometrical position (lat.
or med. shift)
- The angle of the frontal planes of the proximal + distal fragment
- The position of the entry point of the nail
All the landmarks must be exactly achieved intraoperatively visually
and controlled on thescreen with the Patella in front.
Control of the mechanical axis intraoperatively under
Imaging Intensifier with
- grid- radiolucent rulers
on the OT-table!
3. Exact intraoperative control3. Exact intraoperative control
Control of the mechanical axis intraoperatively under
Imaging Intensifier with
- grid- radiolucent rulers
on the OT-table!
3. Exact intraoperative control3. Exact intraoperative control
Control of
mechanical axis
intraoperatively
under Imaging
Intensifier
with
- grid- radiolucent rulers
on the OT-table!
3. Exact intraoperative control3. Exact intraoperative control