ASEPTIC REVISION TOTAL KNEE REPLACEMENT

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ASEPTIC REVISION TOTAL KNEE REPLACEMENT

• Frank Ebert, MD
• Johns Hopkins University Union Memorial Board
  Review

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Revision Total Knee Replacement

• Mode of failure
• Diagnosis
• Classification of failure
• Reconstruction
• Exposure
• Reconstructive principles
• Results

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Mode of Failure

• Septic vs aseptic
• Component loosening
• Component failure (poly)
• Knee instability
• Knee or component malalignment
• Patellar tracking
• Pain
• Other (stiffness, RSD, trauma)

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Diagnosis

• History
• Pain, instability, function
• Duration of symptoms
• Signs of infection
• Examination
• Motion
• Instability
• Metal on metal grinding
• Extensor abnormalities

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Component Loosening

• Rule out sepsis
• Mechanical pain vs pain at rest
• X-rays- best asset (OKU 1995)
• AP, lat, Merchant of patella, long leg standing
• Old xrays
• ?flouroscopy?

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Laboratory Testing

• Aspiration is essential
• CBC, sed rate, C-reactive protein
• Bone scan? Gallium scan? Indium scan? may be
  institution specific
• Indium scan not recommended (Scher et al J of
  Arthro 2000, vol 15)(Joint Diseases)
• Future technology could be polymerase chain
  reaction (PCR) which works off bacterial DNA from
  aspirates

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Component Failure

• Poly wear-through or fracture
• Know the manufacturer of the implant
• Is the poly interchangeable
• Is the implant also loose
• Is there any osteolysis or bone loss
• HAVE A PLAN!

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Knee Instability

• History and physical
• Symmetric laxity requiring a thicker spacer
• Is a thicker spacer available
• Dont get boxed out-are tibial augments indicated
• Dont create a severe patella baja
• PCL rupture that requires a P/S design
• Should you switch to a P/S design if the spacer
  gets over 18 mm?

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Knee Instability

• You must have an array of knees available to
  cover the unexpected finding of greater
  ligamentous deficiency than was expected
• P/S
• P/S stabilized ( TC3 or CCK)
• Hinges and rotating hinges
• Full complement of augments tibia and FEMUR
• Full complement of stems tibia and femur

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Knee Instability

• Flexion/Extension Gap
• If the ligamentous instability is asymmetric then
  the imbalance must be corrected
• This is the same technique that is utilized in a
  primary knee replacement
• Tighten the loose gap
• Change size
• Move component anterior or posterior
• Augmentation blocks on the femur

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TKR Patients with Patellectomy

• Patellectomy patients with total knee
  replacements who develop instability should be
  revised to a P/S design
• Can J Surg 1996 Dec39(6)469-73 Cameron HU, Hu
  C, Vyamont D. 

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Dislocating TKR

• PCL retaining designs should be revised to more
  constrained knee after the ligamentous imbalance
  is diagnosed
• P/S dislocations are more difficult
• Most commonly loose flexion gap
• Malrotation of the femoral component may amplify
  the ligamentous imbalance
• May require a greater degree of constraint

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Component Malalignment

• Excessive internal or external rotation may lead
  to patellar tracking problems
• Femoral component rotation is the key to a square
  flexion gap
• References for correct rotation include
• Transepicondylar axis
• Posterior condyles
• Tibial surface

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Femoral Component Rotation and Flexion gap
Excessive IR with Lateral laxity
Correct rotation with square gap
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Alignment deformities

• Greater than 15 varus
• At 10 years, patients with a fixed varus
  deformity of 15or greater had better pain
  scores, ROM, and Kaplan-Meier survival with a PS
  knee than a CR knee.
• (Laskin et al Clin Ortho
  1996,331)

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Patellar Tracking Problems

• Internal rotation of the femoral component
• Internal rotation of the tibial component
• Functionally increases Q angle
• Malalignment of the the limb
• Medialized position of the femoral component
• Lateralized position of the patellar component

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Patellar Tracking Solutions

• Correct rotation of components
• Correct malalignment of limb
• Place the new femoral component as lateral as
  possible
• Medialize the patellar component
• Close knee in flexion
• Proximally realign the extensor mechanism during
  closure

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Patellar Realignment in TKR

• If a technical problem cannot be identified
• Proximal realignment as described by Insall
• Avoid distal realignment with tibial tubercle
  osteotomy
• High complication rate in TKR
• Can be very difficult to achieve tubercle
  fixation and union with tibial and/or cement in
  place

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• Insall in
• ICL vol 25
• 1986

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Patellar Clunk

• Unique to P/S knees
• The patella may be caught in the housing for the
  post in the femoral component
• May be a design flaw of the implant
• May be secondary to fibrosis of the fat pad at
  the tip of the patella with subsequent catching
  of it in the housing of the post
• Surgical removal of the tissue is indicated
• Open or arthroscopic

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Patellar Clunk

• Extensor Mechanism Problems in Total Knee
  Arthroplasty
• Dennis ICL, 1997
• Patellar Clunk Syndrome
• Hozack et al Clin Orthop 1989241

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Stiffness or Limited ROM

• Etiology
• Technical malposition
• Oversizing of components
• Ligamentous imbalance
• Too much poly
• Tight PCL
• Delayed physical therapy
• Medical complications
• miscommunication

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Stiffness or Limited ROM

• If a mechanical cause can be identified then
  surgery to correct the problem is frequently
  successful
• If delayed therapy is the presumptive diagnosis,
  then open lysis of adhesions should only be
  recommended after a full and aggressive trial of
  physical therapy
• Results in this setting are less predictable

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Revision for only PAIN

• R/O all infectious and mechanical causes
• R/O RSD
• Revision for only pain is usually unsuccessful
  and there are no clear indications
• Jacobs, Hungerford et al Clin Orthop 1988226

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Pre-operative Planning

• Essential
• Necessary equipment
• Instruments
• Implants
• Grafts
• Incision assessment
• Be aware of the components that are in place

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Classification of Tibial Bone Loss in TKR

• Anderson Orthopedic Research Institute

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Type 1 Bone Loss

• Healthy bone
• Normal joint line
• Rim intact
• Minor bone defect
• Defect can be filled with cement or small amount
  of morsellized bone graft

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Type 2 Bone Loss

• Metaphyseal damage
• A is one condyle
• B is both condyles
• Requires reconstruction to restore joint line
• Augment
• Bone
• Longer stem

One condyle or both condyles
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Type 3 Bone Loss

• Major metaphyseal bone loss
• May involve ligament
• Major reconstruction
• Large allograft (structural)
• Major augments
• Tumor custom implant
• More constrained implants

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Classification of Femoral Bone Loss in TKR

• Anderson Orthopedic Research Institute

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Skin Incisions in TKR

• In general keep the incision as close the midline
  as possible and avoid median incisions as the
  oxygenation to the lateral flap has been shown to
  be decreased
• If there are parallel incisions use the lateral
  incision
• Ayers JBJS 199779A

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Exposure in Revision TKR

• Respect old incisions
• Try and maintain 6-7 cm between incisions
• Consults plastics when in doubt
• Anticipate possible flap coverage
• Tissue expanders are occasionally utilized
• Keep skin flaps as thick as possible

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Extensile Exposure in Revision TKR

• Extend incision and quad tendon split
• Perform extensive lateral release first
• Increases exposure
• Usually necessary for patellar tracking
• Quad snip
• Limited improvement but may maintain patellar
  tendon
• No impact on rehab

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Turndown vs Quad Snip
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Quad Snip

• Insall modified the snip to a 45
• Protect SGA
• Easier conversion to turndown
• May be needed for
• V-Y advancement

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Exposure in Revision TKR

• Quad snip
• Some isokinetic weakness Garvin, Scuderi and
  Insall Clin Orthop 321131
• No difference in clinical results Barrack et al
  Instructional Course Lecture
• Quad turndown
• Major exposure improvement
• Delayed rehab
• Significant complications
• Flap necrosis
• Extensor lag

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Exposure in Revision TKR

• Tibial tubercle osteotomy
• Major exposure improvement
• Delayed rehab
• Significant complications
• Non union
• Patellar tendon rupture
• Tibial fracture
• Skin loss

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Tibial Tubercle osteotomy
Total Knee Arthroplasty Krackow 1990
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Tibial Tubercle osteotomy
Total Knee Arthroplasty Krackow 1990
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Exposure in Revision TKR

• The choice between a tibial tubercle osteotomy
  and a quad turndown is a difficult one to make.
  The presence of a large stem or compromised bone
  bed on the tibia would lean one more to the quad
  turndown. Otherwise the choice is up the the
  surgeon as each achieved dramatic exposure
  improvement at the expense of potential
  complications.

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Revision TKR Principles

• Maintain the the joint line
• Reconstruct the distal femur
• Augmentation blocks
• Cement
• Bone
• Failure to do so will lead to premature loosening
  and patellar tracking problems

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Reconstructing Defects

• Metal is biomechanically better than cement or
  cement and screws
• Brooks, Walker Scott et al. Clin Orthop
  1984,184302

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Revision TKR Technique

• Tibial blocks create better cement stresses than
  tibial wedges
• Use a block if you are at the upper limit the
  poly thickness
• Use some level of P/S knee if the PCL is absent
• Always have a more constrained design available
  as a bail-out for the imponderables

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Revision TKR Technique

• Cement works extremely well in rev TKR when it is
  contained
• Morsalized bone graft seems to work well when
  contained and there is a structural rim
• Augments are indicated for uncontained defects
• The role of structural bone graft is promising
  but long term studies are needed

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Failed Guepar hinge
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Cement reconstruction at 10 years
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Revision TKR Principles

• Stems frequently required to avoid supracondylar
  fracture
• This is particularly true for P/S designs
• It is also true when distal and posterior
  augments are used

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Supracondylar Fracture

• Failure to use a stem on this distally and
  posteriorly augmented femoral component caused a
  supracondylar fracture

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BD Post stemmed revision
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Revision TKR Technique

• Address the tibia first
• It allows the predictable creation of a stable
  reference point
• It creates a stable reference platform from which
  the flexion and extension gaps can be assessed
• It creates a stable reference for trial reduction

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Revision TKR Principles

• The next goal is to create symmetric flexion and
  extension gaps
• This can be extremely difficult
• Component rotation
• Bone loss
• Ligamentous instability or deficiency
• Repeated trial reductions are essential and more
  important than jigs

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Symmetric laxity in flexion and extension

• Can usually be solved by adding a thicker poly
  which tightens both gaps symmetricly
• Plan ahead as you may not have enough poly and
  may need an augmentation block
• This can lead to a patella baja
• Occasionally this may require a bigger femoral
  component with a distal and posterior
  augmentation block

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Symmetric vs Loose in Extension
Distal augment
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Loose in Extension

• The solution is to tighten the extension gap and
  lower the joint line by adding a distal
  augmentation block

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Loose in Extension

• Adding a thicker poly is not the answer as the
  knee will jam in flexion as the flexion gap will
  become too tight

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Loose in Flexion

• Ideally you tighten the flexion gap
• Adding posterior augmentation block
• Shifting the femoral component in a posterior
  direction another option
• Go up a size to increase the AP dimension of the
  implant
• Increasing the extension gap by removing distal
  femur is not desirable as it moves the joint line
  proximally and worsens patella baja

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Trials are Critical
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Tighten the Extension Gap
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FIXATION

• The most consistent results have been achieved
  with all components cemented
• This tendency is more dramatic in the tibia and
  the patella
• Recently it has been suggested that cement may
  act as a gasket to help minimize the effective
  joint space and limit osteolysis

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CEMENTLESS FIXATION

• Increased failures
• Femur tibia
• Duffy, Berry, Rand AAHKS Nov 1997
• Increased osteolysis
• 16 overall
• 11 femur
• Cadambi et al J Arthro 1994,vol 9

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•   There have been 10 revisions of the femoral and
  tibial component in the uncemented group, all for
  aseptic loosening or severe osteolysis.  There
  were two revisions in the cemented group for
  aseptic loosening or severe osteolysis.  Survival
  to revision (excluding patella revision) for
  aseptic loosening at 10 years was estimated as
  87 in the uncemented group compared to 96 in
  the cemented group (P0.05).  Ten unrevised
  tibial components and 2 femoral components were
  radiographically loose in the uncemented group
  while 1 tibial component and no femoral
  components were radiographically loose in the
  cemented group.  For the tibial and femoral
  components, survival to revision for aseptic
  failure or radiographic loosening was estimated
  at 72 in the uncemented group and at 94 in the
  cement group at 10 years (P0.0008).
• Conclusions  This study shows a significantly
  higher femoral and tibial component revision rate
  and mechanical failure rate for aseptic loosening
  and osteolysis in the uncemented compared to
  cemented TKA of the PFC design at 10 years. .
  Duffy, et al AAHKS 1997

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Femoral Osteolysis
CM 2 yr post-op
CM 1 yr post-op
CM pre-op
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Femoral Osteolysis
morsellized graft
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Femoral Osteolysis
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Femoral Osteolysis
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Femoral Osteolysis
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Femoral Osteolysis
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Tibial Lysis

• GR at 4 years post-
• op
• GR is symptomatic with tibial pain on weight
  bearing

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Revision for tibial lysis
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Results of Revision TKR

• Large bulk allograft
• 87 good and excellent results in 30 cases at 50
  months with no revisions
• Engh et al JBJS July 1997
• 77 successful results in 28 cases at 50 months
• Ghazavi, Gross et al JBJS Jan 1997

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Massive Allograft
Engh et al JBJS 1997
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Massive Allograft
Engh et al JBJS 1997
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Results Revision TKR

• 75 good and excellent results in 40 cases at 41
  months with a complication rate of 30
• Elia and Lotke Clin Orthop 1991271
• 58 good and excellent results in 27 cases at 9.8
  yrs with 25 reop rate
• Mow and Wiedel Jour Arthro 199813

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Results Revision TKR

• 69 good and excellent results in 39 cases at 45
  months with TC III
• Rosenberg et al Clin Orthop 1991273
• 83 good and excellent results when the cause of
  failure was identified. 0 good and excellent
  when PAIN was the only indication for surgery
• Jacobs, Hungerford et al Clin Orthop 22628

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Summary

• KEYS
• Accurate diagnosis of the failure of TKR
• Careful preoperative planning
• Bone loss
• Complete array of revision components
• Respect the joint line
• Achieve a symmetric flexion extension gap

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Summary

• Even with significant mechanical problems 60
  -75 good and excellent results can be achieved
• Avoid revising knees for pain in which the
  components and ligamentous balance appear correct

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Summary

• Thoughtful
• Well prepared
• Focused
• You will not be hit by the unexpected