William R. Beach, M.D.

Conflict of Interest Statement  Fellowship Grants and Consultant Smith Nephew Arthrex Synthes Mitek  Share Holder Tuckahoe Surgery Center & St. Mary’s ASC Comp Recovery  AANA President and Board of Directors  AAOS Coding, Coverage and Reimbursement Committee

Potential Factors to Consider  Pathomechanical factors Patella alta Trochlea dysplasia Increased lateral position of the tibial tubercle to the femoral sulcus (TT-TG) Secondary soft-tissue problems, ○ Ruptured or attenuated MPFL ○ Weakened or hypoplastic vastus medialis muscle ○ Contracted lateral retinaculum

Pre-op/Critical Question  Is the primary problem secondary to an abnormality of the “alignment vector”? - JP Fulkerson

Proximal or Distal Procedure?  Only a distal procedure will effectively change patellar tracking/alignment Can’t pull the patella into place  A proximal procedure when there is normal alignment but recurrent instability Can hold the patella in place

Tibial Tuberosity Osteotomy (TTO)Techniques  Elmslie -Trillat – “flat cut” medialization  Fulkerson – “anteriomedialization - AMZ”  Maquet – “steep cut’ anteriorization  Preference – Fulkerson (allows infinite angle variations with a single, consistent technique)

Fulkerson Anteromedial Tibial Tubercle Transfer

Fulkerson Anteromedial Tibial Tubercle Transfer (AMZ)  All procedures begin with a diagnostic arthroscopy  Patellar or trochlear chondroplasty (if necessary)  Lateral retinacular release (rarely necessary) If the arthroscope cannot be easily passed between the patella and trochlea If the patella cannot be easily centered in the trochlea with minimal manual pressure

Surgical Set-up  Normal knee holder  U-drape – do not attach the drape to the knee holder  After the knee scope Remove the “paddles” of the knee holder Remove the well leg knee pillow  Extend the leg portion of the table  New ¾ sheet  Knee in full extension

My Surgical “Fulkerson Osteotomy” Technique

Extensile Approach Not Necessary  No need for a long osteotomy  Minimally invasive allows fewer wound issues Faster healing Greater patient satisfaction

Paratenon - original  No longer elevate the paratenon  You can incise along the medial and lateral borders of the patellar tendon and save the overlying paratenon

Paratenon - new  Protect the paratenon directly over the patellar tendon by splitting the paratenon laterally and then medial  Left knee

Anterolateral Calf Musculature  The exposure starts at the patellar tendon  Continues inferiorly along the lateral tibia until the patella tendon fibers end  Then elevate the anterior lateral calf musculature proximally along the tibial flair

Drill Angle is Critical  Based on the arthroscopic findings  Degenerative disease = greater anteriorization  Lateral tracking w/o djd = more medialization  Flat cut

Drill Angle is critical  Steep cut osteotomy  Maximize the anterior and medialization with a 60° drill angle/osteotomy (Farr)

Drill Bits/Cutting Guide  Must visualize the drill bits exit laterally!  Requires more exposure the greater the angulation of the osteotomy = the more you want to anteriorize the tibial tubercle

Drill Bits/Cutting Guides Must be Co-Planar (jig or eye-ball)

Osteotomy  Do not angle the saw blade proximal past the proximal drill/cutting guide  Enter the tibial plateau zone  Must visualize the bits/blade as they exit the lateral tibia  Can Not Be Posterior!

Osteotome  Start the osteotome completion of the osteotomy superior medial  Continue posterior to the patella tendon

Extending the osteotomy  Complete the osteotomy posterior to the patella tendon  Then down the lateral tibia

Osteotome  Connect the retro-patellar tendon portion of the osteotomy to the lateral cut.  The lateral cut was the portion performed with the saw

Complete the osteotomy  Complete the cut by inserting a larger osteotome from the medial side and gentle pry up the fragment  There should be only mild pressure to “crack” the distal portion which was not cut.

Elevate the fragment  Elevate the fragment and rotate it anteriorly and medially  The co-planar osteotomy will easily translate medial and anteriorly

Evaluate the Patellar Position  If you have performed a lateral release palpate the patellar resting position  Or palpating the femoral condyles assessing the patella in the trochlear center  But Not medially

Fixation  Always place the distal screw first  Compresses the proximal portion of the osteotomy  O/w the proximal screw is often too long as it compresses the osteotomy and cause pes bursitis

Screw technique  Use an interfragmentary technique by over-drilling the tibial tubercle fragment and compressing the osteotomy site  The proximal screw should be placed just posterior to the anterior medial tibial cortex

Medial View  Anteriorization & Medialization  Check the anterior medial tibial offset

Lateral view  Anteriorization & Medialization  Check the lateral tibial offset

Smaller and smaller incisions

Fulkerson Anteromedial Tibial Tubercle Transfer  Post-operative protocol Outpatient procedure Hinge knee brace locked in full extension Toe touch to partial weight bearing – immediately advance as tolerated (2° to the short metaphyseal osteotomy) 1 week – F/U heel slides 2 weeks allow 50 degrees of motion 4 weeks allow 90 degrees of motion 6 weeks, if quad strength allows, discontinue the brace

Questions? Thank You