MPFL Complications: Ways to Avoid and How I Salvage! Jason L. Koh, - - PowerPoint PPT Presentation

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MPFL Complications: Ways to Avoid and How I Salvage! Jason L. Koh, - - PowerPoint PPT Presentation

Jan 22, 2023 336 likes •656 views

MPFL Complications: Ways to Avoid and How I Salvage! Jason L. Koh, M.D. Board of Directors Endowed Chair Director, Orthopaedic Institute North Shore University Health System Clinical Professor, University of Chicago Disclosures Consultant

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MPFL Complications: Ways to Avoid and How I Salvage! Jason L. Koh, M.D.

Board of Directors Endowed Chair Director, Orthopaedic Institute North Shore University Health System Clinical Professor, University of Chicago

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Disclosures

  • Consultant for Arthrex, Aesculap, Aperion
  • Research funding from Arthrex, Aesculap, NIH
  • ISAKOS Patellofemoral Task Force Chair
  • ISAKOS Research Committee Deputy Chair
  • Patellofemoral Foundation Board
  • AANA PF Course Master Instructor
  • AOSSM Industry Relations committee
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We all think we drive like this…

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But sometimes…

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WHAT: Medial patellofemoral ligament

  • Primary soft tissue

restraint (53-60%)

  • medial patella to femur
  • Layer 2, deep / confluent

w/undersurface VMO

  • 208 N load (WEAK)

Baldwin AJSM 2009

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What does it do?

  • Tightest in extension
  • LAX in flexion
  • needs to act 0 ~ 20o

until patella engaged in trochlea

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KEY POINTS

  • All grafts >> native MPFL
  • Graft needs to be in the right place!
  • If it’s not in the right place / strain – it will

either stretch out or overconstrain

  • Graft needs to be loose when knee is flexed!
  • Watch your fixation!
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COMPLICATIONS

  • PATELLA SIDE – wrong insertion (less

common)

  • Stress riser – fracture
  • FEMORAL – wrong insertion
  • GRAFT – wrong tension
  • FAILURE – wrong patient
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Patella attachment

  • “bare area” under insertion
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  • Anterior

femoral tunnel

  • (avoid anterior

cortex)

  • Transverse

tunnel in patella

  • Tx:ORIF
  • (Parikh and Wall,

ISAKOS)

Patella fracture

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Follow the tunnel…

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Aim anchor to opposite edge, not cartilage…

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Femoral insertion – xray + palpation

(saddle between medial epicondyle/adductor)

Schottle’s point

Posterior cortex Blumensaat’s Condyle

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Errors in placement

Lyon, France

  • Palpation alone
  • 1/3 >7mm error
  • too proximal =overload

flexion

  • = scores at 2 yr

Servien et al, AJSM 2011

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Pin the tail…38 docs at IPSG

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Results : 18.4% >5mm off

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Patella overload in flexion = overconstrain or patella fracture!

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Femoral insertion

  • Schottle’s radiographic point (femoral

cortex/condyle/Blumensaat’s)

  • Palpate epicondyle and adductor tubercle
  • Graft should loosen in flexion over pin
  • tightens in flexion → move pin distal/posterior
  • place interference screw ~ 20o (Spacer)
  • Make sure graft is not too tight
  • (~10mm lateral glide in extension)
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Test graft strain

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REVISION

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Graft tension too tight

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Medial overload

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Overload on medial side: loose graft

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MPFL Take home

  • Any graft ok
  • Patella insertion broad
  • Femoral insertion btwn epicondyle /adductor
  • Femoral placement critical - use radiographic

landmarks + palpation

  • Lax in flexion, tighter in extension
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Hints

  • Avoid big tunnels in patella!
  • Place femoral tunnel correctly!
  • Patients hate bulky knots under skin!
  • Graft is under less strain in flexion – so it’s ok

to bend the knee early!

  • Quad can be weak for a while (stairs can be 4

mo for descending)

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Thank you!

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Bibliography

  • 1.

Amis, A.A., et al., Anatomy and biomechanics of the medial patellofemoral ligament. Knee, 2003. 10(3): p. 215-20.

  • 2.

Baldwin, J.L., The anatomy of the medial patellofemoral ligament. Am J Sports Med, 2009. 37(12): p. 2355-61.

  • 3.

Bicos, J., J.P. Fulkerson, and A. Amis, Current concepts review: the medial patellofemoral ligament. Am J Sports Med, 2007. 35(3): p. 484-92.

  • 4.

Mountney, J., et al., Tensile strength of the medial patellofemoral ligament before and after repair or

  • reconstruction. J Bone Joint Surg Br, 2005. 87(1): p. 36-40.
  • 5.

Nelitz, M., et al., The relation of the distal femoral physis and the medial patellofemoral ligament. Knee Surg Sports Traumatol Arthrosc. 19(12): p. 2067-71.

  • 6.

Philippot, R., et al., Medial patellofemoral ligament anatomy: implications for its surgical

  • reconstruction. Knee Surg Sports Traumatol Arthrosc, 2009. 17(5): p. 475-9.
  • 7.

Redfern, J., G. Kamath, and R. Burks, Anatomical confirmation of the use of radiographic landmarks in medial patellofemoral ligament reconstruction. Am J Sports Med. 38(2): p. 293-7.

  • 8.

Schottle, P.B., et al., Radiographic landmarks for femoral tunnel placement in medial patellofemoral ligament reconstruction. Am J Sports Med, 2007. 35(5): p. 801-4.

  • 9.

Servien, E., et al., In vivo positioning analysis of medial patellofemoral ligament reconstruction. Am J Sports Med. 39(1): p. 134-9.

  • 10.

Steensen, R.N., R.M. Dopirak, and W.G. McDonald, 3rd, The anatomy and isometry of the medial patellofemoral ligament: implications for reconstruction. Am J Sports Med, 2004. 32(6): p. 1509-13.

  • 11.

Warren, L.F. and J.L. Marshall, The supporting structures and layers on the medial side of the knee: an anatomical analysis. J Bone Joint Surg Am, 1979. 61(1): p. 56-62.