What is the recommended management for an acute patellar dislocation?

Management of Acute Patellar Dislocation

For first-time patellar dislocation without osteochondral fracture, initial conservative management with physical therapy is the standard of care, while surgical stabilization (MPFL reconstruction) should be reserved for patients with high-risk anatomic factors or those who fail conservative treatment with recurrent instability. 1, 2, 3

Initial Assessment and Imaging

Immediate Evaluation

• Obtain knee radiographs (anteroposterior, lateral, and patellofemoral views) as the first imaging study to exclude fractures and assess for patellar subluxation or dislocation 4, 2
• The patellofemoral view specifically evaluates for patellar fractures and subluxation/dislocation 4
• MRI is mandatory for all first-time dislocators (except asymptomatic patients) to evaluate predisposing anatomic factors and detect osteochondral lesions 5

Risk Stratification

Identify high-risk factors that predict recurrence and may warrant early surgical consideration 6, 5:

• Younger age and skeletal immaturity
• Contralateral instability
• Trochlear dysplasia (especially Dejour D)
• Patella alta
• Increased tibial tubercle-trochlear groove (TT-TG) distance >20mm
• Increased patellar tilt
• Low-energy trauma mechanism (inverse correlation: lower trauma intensity indicates more severe underlying abnormalities) 5

Treatment Algorithm

Patients WITHOUT Osteochondral Fracture

Conservative Management (99% consensus) 2:

• Start physical therapy within the first month post-injury 2
• Avoid rigid immobilization—early active range of motion and strengthening are associated with improved outcomes 7
• Use nonrigid bracing for immediate stability during the acute phase 7

Rehabilitation Phases 7:

Acute Phase (0-4 weeks):

• Cryotherapy and compression for effusion management 7
• Early ROM exercises to prevent stiffness 7
• Partial to full weightbearing as tolerated (no significant difference in redislocation rates between protocols) 7

Intermediate Phase (4-6 weeks):

• Progressive open- and closed-chain strengthening exercises 7
• Focus on dynamic knee stabilizers 7

Late Phase (6-8 weeks):

• Sports-specific drills and high-intensity exercises 7
• Neuromuscular training and core strengthening 7

Return to Sport:

• Timeline: 2-4 months post-injury (68% consensus) 2
• Use a brace during return to sport (75% consensus) 2
• Ensure complete healing, limb symmetry on functional testing (Y-balance, triple-hop tests), and psychological readiness 7

Patients WITH Osteochondral Fracture ≥1 cm²

Surgical treatment is recommended (81.5% consensus) 2:

• Perform fragment refixation or cartilage restoration techniques (preferred over fragment removal) 1
• Combine with soft tissue stabilization (MPFL reconstruction) 6, 2
• Delayed repair is favored over immediate fragment removal when urgent surgery is not required 1

Failed Conservative Treatment

Surgical stabilization is indicated if:

• Patellar subluxation episodes occur after 6 months of nonoperative treatment (84% consensus) 2
• MPFL reconstruction is the preferred surgical technique for addressing medial soft tissue stabilizers, offering superior outcomes compared to repair methods 1

Surgical Considerations:

• For patients without high-risk anatomic factors (TT-TG ≤20mm, no severe trochlear dysplasia): isolated MPFL reconstruction reduces instability recurrence from 53.6% to 16.7% at 3 years compared to rehabilitation alone 8
• For patients with high-risk bony factors: combine MPFL reconstruction with correction of relevant bony abnormalities (e.g., tibial tubercle osteotomy for increased TT-TG, trochleoplasty for severe dysplasia) to further reduce recurrence and revision surgery risk 1

Common Pitfalls

• Do not rely solely on clinical examination—MRI is essential for detecting osteochondral lesions and anatomic risk factors that may not be apparent clinically 5
• Avoid prolonged immobilization—this leads to stiffness, muscle atrophy, and worse functional outcomes 7
• Do not dismiss low-energy mechanisms—these often indicate more severe underlying pathoanatomy requiring closer surveillance 5
• Recognize that 50% of patients experience persistent symptoms (pain, swelling, giving way, psychological limitations) even without recurrent dislocation, affecting quality of life and sports participation 5

Follow-Up

• Follow-up as needed (75% consensus) rather than rigid scheduled intervals 2
• Monitor for subjective instability, functional limitations, and psychological readiness for activity 7, 5