High Tibial Osteotomy and Distal Femoral Osteotomy

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High Tibial Osteotomy and Distal Femoral Osteotomy

• Phil Pullen, D.O.
• Garden City Hospital

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History

• Reports of osteotomies in the German literature
  from the 19th century
• Initial procedure is credited to J.P. Jackson
  (reported on 8 HTOs in 1958) for the treatment of
  OA.
• Coventry published results in 1965 and 1973 on 71
  patients described the classic closing wedge
  osteotomy (JBJS)
• Original short term results were satisfactory
  (??) in 80-90

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History

• Longer follow up (7-10 yrs) showed continued
  satisfaction in 60 of patients
• Coventry showed a 60 success rate at 10 years
• Yasuda et al. found 88 of 56 knees satisfactory
  at 6 years and 63 satisfactory at 10-15 years
• Incidence of complications ranged from 10-60

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Osteoarthritis

• TKA has become the major surgical treatment
  option for OA of the knee in the US.
• 250,000 TKAs performed a year
• Cost estimates up near 10 billion with long term
  survival rates (10-15 yrs) of 95
• Concern is with longevity as we lower the age
  limit for arthroplasty

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Pathophysiology of OA

• Felt to be primarily a mechanical problem
• Examples include tibial or femoral deformity,
  intra-articular defects, trauma, osteonecrosis,
  ligamentous laxity, and absence of menisci, all
  can create unfavorable mechanical situations that
  lead to OA

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Pathophysiology contd.

• Current theory is that malalignment leads to
  biochemical changes in the cartilage
• These include increased water content, decreased
  proteoglycan content, and variation in the
  collagen network
• Thus, it is easy to see that correction of
  malalignment would theoretically lead to slowing
  or cessation of this process

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Pathophysiology contd.

• Osteotomy may help to relieve symptoms by
  unloading the forces on the subchondral bone,
  relieving intraosseous venous hypertension, and
  by decreasing the stress on microfractures in the
  subchondral bone

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Alignment

• Mechanical axis that line drawn from the center
  of the femoral head to the center of the ankle
  joint
• Should (approximately) intersect the middle of
  the knee in a normal individual
• Ysu et al showed the average/normal mechanical
  axis to be 1.2 degrees of varus

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Alignment

• Moreland et al. showed it to be 1.3 degrees
• This degree of varus alignment results in 60 of
  load being transferred through the medial
  compartment with WB

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Mechanical Axis
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Alignment contd.

• Anatomic axis is that angle formed by the lines
  drawn from the femoral and tibial diaphyses
  across the knee joint on the AP x-ray
• 5-7 degrees of valgus is considered normal

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Angles of Osteotomy

• With respect to the anatomic axis (5-7 degrees of
  valgus)
• Bauer et al recommended 3-16 degrees of valgus
• Coventry recommended 5 degrees of overcorrection
  (ie. 10-12 degrees of valgus if normal)
• Kettelkamp et al. recommended 8-11 degrees of
  valgus

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Angles of Osteotomy

• With respect to the mechanical axis (1.2-1.3
  degrees of varus), Maquet recommended 2-4 degrees
  of valgus
• All above recommendations were based on patient
  results
• Correction of 7-10 degrees of valgus in the
  anatomic axis should result in satisfactory
  results in 80-90 of the time.

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Angles of Osteotomy

• Excessive valgus angulation was found to not be
  such a mechanical problem as it was to be a
  cosmetic one.
• Insall found that in the long term, degree of
  correction did not correlate with the outcome
• Rather he felt that the disease process seemed to
  continue despite satisfactory alignment

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Indications for Surgery

• In the 60s with limited surgical treatments for
  arthritis, osteotomy was indicated for all types
  of joint conditions
• Widely accepted indications are now available
  since the development of the TKA and since long
  term results from HTO became available

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Indications for Surgery

• Age
• Weight
• Range of Motion
• Activity Level
• Type of Disease
• Instability

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Age

• Many state 65 years of age should be the upper
  limit of normal
• However increasing life expectancy should be
  considered as well

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Weight

• Normal weight patients are better suited for
  osteotomy than obese patients
• Coventry recommended treatment of obesity to be a
  prerequisite for osteotomy
• Conversely, studies by Krakow and Mont et al. and
  Partio, Orava, and Lehto et al. show no
  correlation between results of TKA and patient
  weight at 7-10 years.

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Range of Motion

• Morrey recommends ROM be nearly 90 degrees with
  less than 20 degrees of flexion contracture
• Bochner states 90 degrees of flexion and less
  than 15 degrees of flexion contracture are
  necessary pre-op

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Activity Level

• Activity that would be prohibited following TKA
  would make one lean towards osteotomy
  consideration if other indications were met

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Type of Disease

• Best reserved for OA and posttraumatic arthritis
• Inflammatory arthritis is generally thought of as
  a contraindication
• Patients with generalized disease such as with RA
  have success rates as low as 20

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Instability

• Is no longer considered an absolute
  contraindication for osteotomy
• It should however be considered in pre-op
  planning
• For instance, medial instability can be corrected
  by opening wedge osteotomy, combined medial
  opening/lateral closing wedge osteotomy, or
  ligament advancement

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Pre-Op Planning

• Full length film of the leg is ideal to assure
  the restoration or overcorrection of the
  mechanical axis
• The simplest method for determining the angle of
  correction involves drawing a line from the
  center of the femoral head to the the lateral
  margin of the tibial spine and then a line from
  the lateral tibial spine to the center of the
  ankle.
• The angle from these 2 lines represents your
  angle of correction

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Angle of Correction
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High Tibial Osteotomy

• Valgus proximal tibial osteotomy for
  unicompartmental arthritis with varus deformity
  is the most common
• Coventrys lateral closing wedge osteotomy is
  still the most popular osteotomy used in the US
• It is relatively simple to perform and had a high
  rate of healing due to the large surface area of
  the cancellous bone involved

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Disadvantages of Lateral Closing Wedge Osteotomy

• Shortening of the leg
• Lateral collateral laxity
• Infrapatellar scarring patella baja (exposure
  more diff in future TKA)
• Increased Q angle
• Limited correction
• Predisposition to fracture because of size of
  proximal fragment

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Disadvantages of Lateral Closing Wedge Osteotomy

• Closing wedge can also lead to offset which can
  affect future TKA
• Especially if a tibial stem is needed
• Thus, making a primary knee a revision knee
  surgery
• Cosmesis is of concern to some patients
  (valgusgtvarus osteotomies)

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High Tibial Osteotomy

• Medial opening wedge osteotomy with iliac crest
  bone grafting
• This can be used to tighten the MCL
• Disadvantages include lengthening of the leg,
  displacement of the patella distally, possible
  nonunion, and bone graft donor site morbidity

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High Tibial Osteotomy

• A combined medial opening and lateral closing
  wedge osteotomy can be used to tighten the MCL
  and also eliminate bone graft donor site morbidity

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High Tibial Osteotomy

• Jakob and Murphy described an osteotomy performed
  behind the tibial tubercle
• This offered high rates of healing, greater
  angular correction, and avoidance of the
  infrapatellar fat pad and subsequent scarring

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High Tibial Osteotomy

• Nakhostine et al. described an oblique prox
  tibial osteotomy which helped to preserve the
  medial cortex and IT band insertion and allowed
  for early wt. bearing

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Correction of the Fibula

• In order to allow for correction of tibial
  deformity the fibula must be untethered
• Fibular osteotomy can be through the fibular
  shaft or more proximally in the fibular head or
  neck
• Care must be taken to avoid injury to the
  peroneal nerve at all areas but especially near
  the fibular neck

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Correction of the Fibula

• Resection of the fibular head and dividing the
  proximal tibia-fibular joint are 2 other
  techniques
• These can be associated with LCL laxity
• Krakow prefers to extend the wedge shaped
  osteotomy laterally through the fibula
• This allows the LCL attachment to remain intact

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Methods of Fixation

• Include casts, staples, plates and screws, and
  external fixators
• Coventry described the use of a stepped staple in
  1969
• Krackow and Phillips prefer fixation with staples
  2-3 lateral Coventry staples provide adequate
  fixation

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Proximal Tibial Varus Osteotomy

• The natural valgus tibiofemoral orientation led
  many to conclude that 12 degrees of valgus
  deformity is the upper limit of consideration for
  varus proximal tibial osteotomy
• When the valgus deformity is more than 12
  degrees, the plane of the joint line deviates
  from the horizontal and a DFO is preferred

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Proximal Tibial Varus Osteotomy

• MCL laxity can occur if the wedge is taken from
  above the MCL insertion site
• MCL advancement on the tibial side can address
  this problem
• Small degrees of deformity (lt12 degrees) and
  specific situations, such as malunion of a
  proximal tibia fracture when the deformity is
  below the joint line

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Distal Femoral Osteotomy

• Limitations of proximal tibia varus osteotomy led
  surgeons to recommend distal femoral osteotomy
• Valgus deformity and lateral compartment
  arthritic involvement (much less common than
  medial compartment disease)
• Typically occurs in females and the treatment of
  choice with respect to osteotomies is a femoral
  varus-producing osteotomy

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Distal Femoral Osteotomy

• Healy and associates reported 93 good to
  excellent results at 4 years in 15 knees
• McDermott et al had 92 success at 4 years
• The desired degree of correction is variable
• Some recommend a 0 degree tibiofemoral angle and
  a horizontal joint line
• Morrey and Edgerton recommend having the
  mechanical axis medial to the middle portion of
  the medial plateau

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Distal Femoral Osteotomy

• Usually performed as a medial closing wedge
• Traditionally have been fixed with angled blade
  plates
• The single most common complication following DFO
  is inability to restore the desired anatomic
  valgus alignment