MR Imaging after Patellar MACI and MPFL Reconstruction: Comparing Isolated with Combined Procedures

Presentation Format: Oral presentation.

Purpose or Learning Objective: To evaluate qualitatively and quantitatively whether the 2-year magnetic resonance imaging (MRI) outcome after isolated medial patellofemoral ligament (MPFL) reconstruction for treatment of patella instability and after isolated matrix-induced autologous chondrocyte implantation (MACI) for the treatment of focal cartilage defects at the patella is better than after combined procedures.

Methods or Background: In 66 consecutive patients with MACI at the patella (cartilage repair [CR]; n = 16), MPFL reconstruction (MPFL; n = 31), or combined surgery (CR&MPFL; n = 19), MRI was performed 2 years after surgery. Clinical pulse sequences included two-dimensional (2D) intermediate-weighted turbo-spin-echo (TSE) sequences in three planes and sagittal T1-weighted TSE sequences. A sagittal 2D multislice multiecho (MSME) spin-echo sequence was implemented for postoperative quantitative cartilage T2 and T1rho relaxation time measurements. Clinical (Knee Injury and Osteoarthritis Outcome Score [KOOS] and Lysholm) and MRI observation scores (Whole Organ Magnetic Resonance Imaging Score [WORMS] and Magnetic Resonance Observation of Cartilage Repair Tissue [MOCART]) were obtained. Statistical analyses included descriptive statistics, Mann-Whitney U test, and Pearson correlations.

Results or Findings: Follow-up time (FU; 27.4 ± 8.1 months), age (22.8 ± 6.4 years), and body mass index (23.54 ± 8.13) were not significantly different between the groups (p > 0.05). Overall outcome 2 years after surgery was satisfying (WORMS progression: − 2.3 ± 6.5; MOCART score: 68.4 ± 29.5). The WORMS scores at FU were significantly higher in the CR&MPFL group (8.7 ± 4.9) than in the CR group (4.3 ± 3.6; p = 0.005) and in the MPFL group (5.3 ± 5.7; p = 0.004). Patellar cartilage defects were more severe in the CR&MPFL group (3.7 ± 1.7) than in the other groups (CR: 1.1 ± 0.9; MPFL: 1.6 ± 1.3; p < 0.01). MOCART scores were significantly better in the isolated CR group than in the CR&MPFL group (87.8 ± 8.9 versus 56.6 ± 27.6; p < 0.001). Perfect defect filling was achieved in 69% of cases in the CR group and in 26% of cases in the CR&MPFL group (p = 0.031). Global and patellar T2 values were higher in the CR&MPFL group (T2 mean: 34.0 ± 2.8; T2 patellar: 36.7 ± 5.2) and in the CR group (T2 mean: 35.5 ± 3.1; T2 patellar: 35.7 ± 2.4) as compared with the MPFL group (T2 mean: 31.1 ± 3.2; T2 patellar: 33.5 ± 3.1; p < 0.05). T2 values correlated significantly with clinical scores (< 0.005).

Conclusion: In patients case with combined surgery, inferior CR tissue quality and more severe cartilage matrix degeneration and degenerative changes at the knee occur. Therefore, patients with a need for combined surgery may be at particular risk for early osteoarthritis.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
03 June 2021