High Tibial Osteotomy

1. HTO
Planning : How to do it
Dr Abhishek Kaushik
AO Fellow (Austria)
AO National Faculty
FJR (USA, UK and Germany)

2. Learning objectives
• Historical aspects
• Physiological axis and anomalies
• Indications
• Principle of osteotomy
• Planning (Medial Open Wedge)
• Techniques
• Complications
• Take home

3. History
Those who cannot remember the past, are condemned to repeat it
• First modern osteotomy
was done by American
John Rhea Barton (1794–
1871) on sub-trochanteric
femur.
• Bernhard Heine (1800–
1846) from Germany
designed first working
osteotome

4. • Bernhard Rudolf Konrad von
Langenbeck (1810–1887)
professor in Göttingen, Kiel, and
Berlin, Germany, was the first to
describe a subcutaneous
osteotomy technique
• Theodor Billroth (1829–1894)
Professor in Zürich, Switzerland
and Wien, Austria designend a
chisel.

5. • Sir William Macewen (1848–1924),
Professor in Glasgow, performed
the first antiseptic osteotomy in
Great Britain on April 11, 1875.
• In 1884, he presented his series of
1,800 cases without major
complications.
• His major work was on
supracondylar region of humerus.

6. • Jackson, Waugh, Gariépy,
Coventry were first to perform
proximal tibial osteotomy for
osteoarthritis knee.
• Jackson did it distal to tibial
tubercle
• Coventry “Classical” lateral
closed wedge valgization type
with fibular osteotomy done
proximal to tibial tubercle.

7. • Open-wedge osteotomy was
first described by Lexer (1931).
• In 1969 the AO advocated
fixation using an angular plate
for either varization or
valgization osteotomy on the
distal femur

8. Knee Axis
• The knee joint is the
largest and most
complex joint in the
human body and has
the longest lever
arms.

9. • The mechanical axis of the leg (Mikulicz
line) runs from the center of the
femoral head to the center of the ankle
joint.
• Under physiological conditions this line
runs on average 4 (± 2) mm medial to
the center of the knee joint. (MAD)
• The anatomical and mechanical femoral
axes form an angle of 6° (± 1°) (aMFA).

10. • The tibial plateau is
slightly shifted in a
posterior direction in
relation to the axis of the
femoral diaphysis
• Tilted caudally by 10° in
relation to the horizontal
line in the sagittal plane
(tibial slope).

11. Deformed Leg / Knee
• Deformities of the lower limb are defined as a
deviation of the physiological axes
• Can be pathologically altered in the frontal,
sagittal or transverse or torsional plane.
• The most frequent pathologies and therefore
those of greatest clinical relevance are varus-
valgus deformities in the frontal plane.

12. Varus
• Anatomical femorotibial
angle > 173–175°
• Mikulicz line runs medial
to the 4 mm point,
significant in MAD >
15mm medial to the
center of the knee joint
• Increased intercondylar
distance

13. Valgus
• Anatomical femorotibial
angle < 173–175°
• Mikulicz line runs lateral to
the 4 mm point, significant
in MAD > 10 mm lateral to
the center of the knee
joint
• Increased inter-malleolar
distance

14. Causes
• Congenital deformities
• Constitutional deformities
• Growth disorders with premature partial closure
of the epiphyseal plate
• Metabolic diseases (eg, rachitis)
• Osteopathies (eg, renal osteopathy)
• Posttraumatic deformities
• Secondary deviation due to destruction of the
joint surface (infection, Tumors)
• Degenerative

15. Evaluation
MAD –Mechanical Axis Deviation

16. • Clinical evaluation for ligaments, skin and soft
tissues.
• Examination of Hips, knee and spine must be
done.
• X-rays standing and Stress views and patella
views.
• CT scannogram for measurement of angles.
• MRI for evaluating cartilage, ligaments.

17. X-rays

18. CT Scan

19. Indications
• Oseoarthritis Patients With Varus Limb
Alignment
• Oseoarthritis Patients With Valgus Limb
Alignment
• Adult Osteochondritis Dissecans.
• Osteonecrosis
• Postero-lateral Instability
• Chondral Resurfacing

20. Planning
• Selection of patient: Most Important
• Determining the deformity (Plane , Angle)
• Determine the amount of correction desired
• Choice of osteotomy
• Implant selection
• Develop a surgical plan
• Execute

21. Patient Selection Guidelines
• Stage of osteoarthritis (Uni / Bi/Advanced)
• Ligamentous status
• Type of deformity and reducibility
• Age
• Range of motion
• Obesity
• General medical status
• Activity levels
• Patient’s expectations.

22. The Ideal patient for a HTO
• Younger than 65 years (male) respectively 55
years (female)
• Metaphyseal varus deformity of the tibia (TBVA >
5°)
• Intact lateral compartment
• Normal range of motion (<10° extension deficit)
• Non-smoker (better healing)
• Has a certain pain tolerance
• May have ACL or PCL deficiency (can be
addressed by the surgery by correcting slope)
• BMI under 30

23. The ideal candidate for a UKA
• Older than 55 years
• Has no osseous deformity and mere intra-
articular wear.
• Intact ligaments ( ACL, MCL)
• Has a deformity which reduces completely in 20°
of flexion under valgus stress
• Has an intact lateral compartment
• Has an almost normal range of motion
• Has no inflammatory disease
• Should preferably have a BMI under 30

24. The ideal candidate for a TKA
• Is older than 75 years
• Has generalized and manifest osteoarthritis of the
knee
• Has significant and continuous pain during
activities of daily life
• May have extension or flexion deficits
• May have axis deviation and bone deficiencies
• Has limited expectations regarding activity and
range of motion
• May have ligament balance issues.

25. Contraindications of HTO
• Correction needed >20
• Flexion contracture >15 ̊
• Knee flexion <90 ̊
• Tibial subluxation >1cm
• Medial compartment tibial bone loss >3mm
• Patella baja*
• Inflammatory arthritis
• Morbid obesity
• Advancing Age

26. Other Factors
• Surgeons' Skillset ( UKA/HTO/TKR)
• Infrastructure available
• Financial factors

27. Nature and localization
• Prerequisites for the planning process are
• A good quality weight-bearing x-ray of the
entire lower extremity
• Definition of the type and localization of the
deformity
• Knowledge of any associated ligament
instability

28. Nature of Deformity
• Varus deformity with
• No loss of med cartilage
• 1/3 loss of medial cartilage
• 2/3 loss of medial cartilage
• Bone on bone arthrosis
• ACL Deficiency
• PCL deficiency
• Axial Rotation components
• Femoral deformity
components

29. Localization
• Frontal and sagittal plane evaluation
• a. Weight-bearing line
b. Mechanical axis of femur and tibia
c. Joint orientation angles
d. Location of deformity (CORA)
• Bowing of femur or tibia may coexist
• Deformity in distal femur may coexist
• Deformity in ankle

30. • Effect of ankle joint line
inclination on HTO
• Ankle joint inclined:
corrects to normal after
closed Wedge HTO
• Ankle joint parallel to
knee: gets inclined after
surgery.

31. Planning
• Level of osteotomy:
• Should be performed at the apex of the
deformity for optimal correction.
• The metaphysis of a long bone is the region of
best healing capacity; Healing time favors tibia
over femur.
• Double osteotomy may sometime be needed
in complex deformities.

32. Planning
• Open v/s Closed:
• Open-wedge are generally easier and more
precise to perform.
• Opening procedure allows for intraoperative
“fine-tuning” by adjusting the opening.
• Open wedge may require bone grafting. ( not
in angle stable devices)
• Open may have more chances of delay union.

33. Open v/s Closed
• Patella baja (Rel
elevation of Joint line)
• Insufficient medial
collateral ligament
(open-wedge technique
allows tensioning)
• Simultaneous medial
arthrotomy is required.
• Patella alta (Relative
lowering of joint)
• Intact medial collateral
ligament
• Simultaneous lateral
arthrotomy is required

34. • Open-wedge HTO
• Faster surgery
• Bone graft necessary in
case of high correction
• Higher precision
• Risk of saphenus nerve
lesion
• Gain in Limb length ( av
5.5 mm)
• Longer consolidation
• Closed-wedge HTO
• Longer surgery
• No graft necessary
• Lower precision
• Risk of peroneus nerve
lesion
• Shorter consolidation
• Loss of limb length (2.4
mm)

35. • Correction of Sagittal Plane:
• If anterior knee instability ( ACL insufficiency)
is present, the tibial slope should be
decreased (<5ᴼ ) to minimize anterior force.
• Posterior cruciate ligament (PCL insufficiency)
the slope should be increased (up to 12ᴼ) to
reduce posterior force vector.

36. Effect of slope correction on tibial
translation

37. • Correction at transverse plane
• Should be corrected at the level of deformity
to achieve optimal patellar tracking
• Location of Hinge points:
• Importance of choosing correct hinge points
of osteotomies in open or closed wedge
procedures can’t be overemphasized.

38. Amount of correction
• Goal is to normalize the mechanical axis or to
overcorrect it to valgus side.
• Determination of the correction depending on
residual cartilage thickness in the involved
compartment : Fujisawa Scale

39. Fujisawa Point
• Its an imaginary point
on lateral tibial condyle
at 62% of scale of tibia
from medial to lateral (
0 to 100%) or at 31% of
lateral tibial plateau
from center.

40. Fujisawa scale
• In a well-aligned knee,
load distribution is not
well-balanced but
physiologically 60% in the
medial and 40% in the
lateral compartment

41. • Overcorrection by shifting
the weight-bearing line
slightly to the lateral
compartment is required.
• The correction between
10% and 35% laterally on
the Fujisawa-scale is adv.

42. Angle of Correction required
• Mathematical method
• c × (ΔS)
β= -------------
TW
• C constant 76.4
• ∆ S : incremental
lateral joint separation

43. • In the given case.
• TW 80 mm
• ∆S is 4 mm (7-3 mm)
• So the angle required will be 3.8 ∘

44. Amount of Wedge required
• It depends upon width of proximal tibia and
angle of correction required.
• Length = Diameter of tibia X 0.02 X Angle

45. Table for measuring resection size

46. Correction Angle
• On paper tracings of
x-rays
• Draw a line from Head
of femur to Fujisawa
point.
• Second line from just
above tip of fibula to
center of ankle

47. • Calculate the angle
between two lines.
• Draw that angle on
proximal tibia with
apex at just above tip
of fibula.
• Cut the line and open
the wedge to see the
correction.

49. Surgical Plan

51. • Superficial MCL is
identified and
divided
• And pes is identified.

52. • Osteotomy is marked in
an reverse L shaped line
with horizontal limb
parallel to Pes anserinus
and then turning the
vertical limb to an angle
of 110 ᴼ just medial to
tibial tuberosity and
then going anteriorly
across.

54. • Parallel guide wires are
placed usually using the
jig

55. • Length is measured to
know the length of
osteotomy

56. • Osteotomy is
performed using saw or
osteotome with desired
angle using markings or
angle guides.
• Do not pierce the lateral
cortex.

57. • Anterior part of
osteotomy completed
taking care not to injure
tibial tuberosity or
patellar tendon.

58. • Lateral cortex s not fully
broken while
performing osteotomy
to keep the medial
hinge intact.
• Chisels are inserted one
over other to distract
the osteotomy

59. • Osteotomy further
opened up using
spreader chisel to
desired correction angle
and also advanced till
lateral cortex to open it
fully.

60. • Finally using laminar
spreader the osteotomy
is opened up and fine
tuning can be done
here.

61. • Osteotomy tuned to see
the axis correction using
long rods and C arm

62. • When desired
correction is achieved ,
osteotomy kept open
and plate fixation starts.
• Proximal parallel screws
guide pins inserted
• Plate is pre-loaded by
putting spacer screws in
proximal and distal
holes

63. • Position should be
checked under c arm

64. • After applying proximal
locking screws one
cortical screw is applied
in first distal hole.

65. • Cortical screw should
be applied little
obliquely to avoid
interfering with lock
screw to be used later

66. • Tightening of cortical
screw would cause the
compression of lateral
cortex
• This is caused by pre-
loading effect of
block/spacer screws
used previously.

67. Sagittal correction
• Concept of sagittal
correction
• Neutral
• Flexion( for Posterior
instabilities)
• Extension (for Anterior
Instability)

68. • Sagittal correction can
be done and position
finalized

69. Case example
• Varus deformity with
medial joint
involvement.

70. After osteotomy.

71. Problems
• Unhappy patient ( unsuitable patient selected)
• Under and overcorrection.
• Delayed healing
• Non healing
• Implant related problems
• Problems related to patella
• Persistent/New instability

72. • Plate causing impingement to hamstring
tendons.
• Compartment syndrome *

73. Results

75. Take home message
• Lateral Opening wedge osteotomy is a useful
procedure in addressing medial joint arthritis
in young adults
• Requires suitable patient selection and
meticulous planning
• Long term Results are good and can be easily
converted to total knee whenever required.

76. Thanks