What is the best treatment approach for a patient with patellar dislocation?

Treatment of Patellar Dislocation

For first-time patellar dislocation, nonoperative management with functional bracing is the recommended initial treatment unless imaging reveals an osteochondral fracture or significant soft tissue disruption requiring surgery. 1

Immediate Management

Pain Control

• Administer NSAIDs as first-line analgesia for acute pain relief 1
• Add opioid analgesia if NSAIDs provide insufficient pain control, particularly when severe symptoms like vomiting are present 1
• Apply ice therapy immediately using melting ice water through a wet towel for 10-minute periods, repeated as needed 1

Immobilization Strategy

• Avoid rigid immobilization beyond 10 days maximum if used at all for severe pain or edema 1
• Transition to functional support early to prevent stiffness and impaired mobility 1

Mandatory Imaging Protocol

Initial Radiographs

• Obtain anteroposterior and lateral radiographs immediately to assess for fractures and confirm reduction 1, 2
• Add patellofemoral (axial) view to evaluate patellar fractures and degree of subluxation 1
• Use weight-bearing axial views when possible to better assess patellofemoral kinematics 3

MRI Evaluation

• Perform MRI after initial radiographs to characterize bone and soft-tissue injuries, including osteochondral fractures, bone marrow contusions, and medial patellofemoral ligament (MPFL) injury 1
• MRI reliably identifies risk factors for chronic instability and assesses joint damage that guides treatment decisions 4
• The typical injury pattern includes MPFL tear (almost always present) and bone bruises of the patella and lateral femoral condyle 4, 5

CT for Surgical Planning

• Use CT for detailed assessment of axial malrotation and bony anatomy when surgical intervention is being considered 2, 3

Treatment Algorithm Based on Imaging Findings

No Osteochondral Fracture (Nonoperative Management)

• Proceed with functional bracing using an ankle-style functional brace for 4-6 weeks 1
• Approximately 60-70% of patients respond well to nonoperative treatment 1, 6
• This approach is appropriate when there is no osteochondral fracture, no substantial disruption of medial stabilizers, and the patella is not laterally subluxated with normal contralateral alignment 6

Osteochondral Fracture Present (Surgical Management)

• Surgery is indicated primarily for osteochondral fractures or significant concomitant injuries identified on imaging 1
• Other surgical indications include substantial disruption of medial patellar stabilizers, laterally subluxated patella with normal contralateral knee alignment, or second dislocation 6
• Free bodies or osteochondral fragments require surgical treatment 5

Risk Stratification for Recurrent Instability

High-Risk Features Requiring Closer Follow-up

• Age younger than 25 years with trochlear dysplasia carries a 60-70% risk of recurrence by 5 years 7
• Immature physes, sports-related injuries, patella alta, and trochlear dysplasia all increase recurrence risk 7
• Approximately 30% of patients managed nonoperatively will experience recurrent instability 7

Anatomic Risk Factors to Document

• Trochlear dysplasia using Dejour classification 4, 7
• Patella alta using Caton-Deschamps or Insall-Salvati indices 7
• Increased tibial tubercle-trochlear groove distance (TT-TG) on CT 5
• Consider orthotic devices for patients with foot pronation or pes planus contributing to malalignment 2, 3

Critical Pitfalls to Avoid

• Do not immobilize rigidly for more than 10 days, as this increases stiffness and impairs mobility 1
• Do not dismiss vomiting as purely pain-related without imaging—it could indicate a displaced osteochondral fragment requiring surgical intervention 1
• Do not treat conservatively if MRI reveals large osteochondral lesions or pronounced ligamentous tears, as these require prompt surgery 4, 6

Surgical Options for Recurrent Instability

When conservative management fails or for recurrent dislocations:

• MPFL reconstruction is effective in many cases and is the most common procedure 8
• Tibial tubercle osteotomy realigns the extensor mechanism for lateralized tibial tubercle or patella alta 8
• Trochleoplasty or tibial tubercle osteotomy for patients with trochlear dysplasia 8
• Address chondral lesions with débridement, structural grafting, or cell-based treatment depending on size and symptoms 8