What is the appropriate management for a high‑grade (grade III) medial patellofemoral ligament (MPFL) tear in a young active adult?

Management of High-Grade MPFL Tear in Young Active Adults

For a young active adult with a high-grade (grade III) MPFL tear and recurrent patellar instability, MPFL reconstruction is the definitive treatment, demonstrating superior outcomes with only 6-16% recurrent dislocation rates compared to 54% with nonoperative management. 1, 2

Initial Assessment and Decision Algorithm

Determine if Surgery is Indicated

• Recurrent instability (≥2 dislocations): Proceed directly to MPFL reconstruction 2
• First-time dislocation with grade III tear: Consider initial conservative management with close monitoring, as surgical repair of acute injuries shows no benefit over nonoperative treatment 3
• Assess anatomic risk factors on imaging that would necessitate additional procedures beyond isolated MPFL reconstruction 2:
  • Tibial tubercle-trochlear groove (TT-TG) distance >20mm
  • Severe trochlear dysplasia (Dejour type D)
  • Patella alta (CDI >1.3)

Key Imaging Findings to Document

• MRI classification of patellar MPFL injury 3:
  • Type P0: Ligamentous disruption at patellar attachment
  • Type P1: Bony avulsion from medial patellar margin
  • Type P2: Osteochondral avulsion from medial facet (requires surgical fixation)
• CT measurements: TT-TG distance, patellar tilt angle, and patellar height indices (ISR, CDI, BPR) 4, 2

Surgical Management: MPFL Reconstruction

Reconstruction vs Repair Decision

Always choose reconstruction over primary repair for grade III tears, as reconstruction demonstrates significantly lower recurrent dislocation rates (6.3% vs 36.9%) even at midterm follow-up 1. Primary repair only shows acceptable outcomes in acute type P2 injuries requiring osteochondral fragment fixation 3.

Surgical Technique Considerations

• Graft options with proven efficacy 4, 5:
  • Quadriceps tendon autograft (partial thickness strip)
  • Polyethylene suture (FiberTape) combined with medial retinaculum plication
• Arthroscopic approach allows concurrent treatment of intra-articular pathology 4
• Anatomic femoral tunnel placement is critical to restore normal patellofemoral kinematics 6

Expected Outcomes Post-Reconstruction

• Instability resolution: 84-94% remain dislocation-free at 2-3 years 4, 2
• Functional improvement 4, 5:
  • Kujala scores improve from 36-82 preoperatively to 87-98 at 24 months
  • Lysholm scores improve from 33-79 to 90-97
  • IKDC scores improve from 49 to 91
• Patellar height correction: Isolated MPFL reconstruction significantly reduces patella alta (CDI decreases by 0.1-0.15 units), particularly beneficial in patients with preoperative CDI >1.3 7
• Return to sport: 70-78% return to baseline activity levels 1, 5

Critical Risk Stratification

Predictors of Reconstruction Failure

Elevated patellar height (CDI >1.3) in the repair group was the only identified risk factor for recurrent instability, with mean CDI of 1.30 in failures vs 1.18 in successes 1. However, reconstruction appears protective even with patella alta 7.

When Additional Procedures Are Required

If anatomic risk factors exceed thresholds (TT-TG >20mm, severe dysplasia), isolated MPFL reconstruction is insufficient and requires concurrent tibial tubercle osteotomy or trochleoplasty 2. The evidence provided focuses on isolated MPFL reconstruction in patients without these high-risk features.

Nonoperative Management (Limited Role)

Conservative treatment with active rehabilitation alone results in 54% persistent instability at 3 years, making it appropriate only for 2:

• First-time dislocations without recurrence
• Patients declining surgery
• Those with contraindications to surgery

Both operative and nonoperative groups show similar patient-reported outcome scores, but the reconstruction group has objectively superior stability 2.

Common Pitfalls to Avoid

• Do not perform primary MPFL repair for grade III tears expecting durable results; the 37% failure rate is unacceptable in young active patients 1
• Do not overlook type P2 injuries on MRI, as these osteochondral fragments require acute surgical fixation regardless of dislocation frequency 3
• Do not proceed with isolated MPFL reconstruction if TT-TG >20mm or severe trochlear dysplasia is present without addressing these anatomic abnormalities 2
• Do not use CDI >1.3 as a contraindication to isolated MPFL reconstruction, as the procedure itself corrects patella alta 7