Longitudinal Evaluation of Cartilage Degeneration Following ACL Injuries using Quantitative MRI

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Longitudinal Evaluation of Cartilage Degeneration
Following ACL Injuries using Quantitative MRI

• C. Benjamin Ma
• Alekos Theologis
• Radu I Bolbos
• Xiaojuan Li
• Sharmila Majumdar
• University of California San Francisco
• Department of Orthopaedic Surgery
• Department of Radiology

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Financial Disclosures

• Nothing to disclose
• Study funded by K25 AR053633, Aircast Foundation
  Award and RO1AR46905

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Long-term success of ACL injury

• 103 female soccer players with ACL injury gt 12
  years
• Mean age 31 (26-40yo)
• 82 had radiographic changes
• 51 fulfilled radiographic OA
• 60 had ACL recon
• Surgical reconstruction no influence on knee
  symptoms

Lohmander et al, Arthritis Rheum 2004
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ACL and Arthritis

• 16 year old soccer player with ACL tear
• 26 year old..
• 50 with radiographic arthritis????
• 36 year old..?

Can we pick up cartilage degeneration earlier?
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Quantitative MR imaging using T1rhoT1rho in
controls vs. OA

• T1? values were elevated in all regions of the
  knee

Li et al, Magn Res Medicine 2005
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Methods

• 9 patients with acute ACL injuries and 7 healthy
  controls were studied.
• Sagittal 3D quantitative T1? images were acquired
  within 4 weeks of the injury and at 0.5, 6, 12,
  and 24 months following ACL reconstructions.
• The volume and signal intensity of BMEL were
  quantified.
• T1? values were quantified for cartilage
  overlying (OC) bone marrow edema lesions (BMEL)
  and surrounding cartilage (SC).

Yellow region represents the bone marrow edema
lesion (BMEL). The blue region represents
surrounding cartilage (SC) and red region
represents the overlying cartilage (OC)
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Methods

• The four compartments of the knee were divided
  into sub-compartments, and T1? values were
  quantified for each sub-compartment and compared
  to controls.
• T1rho values for deep and superficial layers of
  OC, SC, and cartilage sub-compartments were
  further calculated using an in-house developed
  laminar analysis program.

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Results

• BMEL were most commonly found in the lateral
  tibia (LT) and lateral femoral condyle.
• Nearly 80 of BMEL resolved over a 2-year period.

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Lateral Compartment

• OC in the LT have significantly elevated T1?
  values when compared with surrounding cartilage
  immediately following injury and throughout the
  first 24 months.
• Zonal analysis showed significantly elevated T1?
  values in the superficial layer of the OC to the
  superficial layer of the SC at baseline, 2 weeks,
  and 6 months
• T1? values were found to be higher in the deep
  layer of the OC relative to the deep layer of the
  SC, although no significant differences were
  found

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Medial Compartment

• No significant differences between healthy
  controls and ACL injured knees at time 0, 0.5,
  and 6 months follow-up.
• Both the superficial and deep layers of MT-2 had
  significantly higher T1? values at 12 and
  24months compared to baseline.
• The superficial layer in MT-2 at 12 -24 months
  also had significantly higher T1? values than
  control.

T1rho value of the deep and superficial zone
cartilage at region MT-2
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Summary

• Elevated T1rho in cartilage overlying bone marrow
  edema lesions, lesions are predominantly in the
  lateral compartments
• Superficial layers of overlying cartilage sustain
  more severe damage than deep layers.
• Lateral compartment lesions are present
  immediately following injury and have no recovery
  in 24 months
• Despite ACL reconstruction, superficial layers of
  cartilage in the medial compartment not protected
  by the meniscus show signs of degeneration as
  early as 1 year after injury and reconstruction.