What is the management and treatment for a patient with lateral patellofemoral dislocation?

Management of Lateral Patellofemoral Dislocation

For acute lateral patellar dislocation, functional support with an ankle-style brace for 4-6 weeks is the first-line treatment, avoiding rigid immobilization and reserving surgery primarily for osteochondral fractures or significant concomitant injuries. 1

Initial Diagnostic Workup

Imaging sequence:

• Obtain anteroposterior and lateral radiographs immediately as the first-line imaging modality 1
• Add a patellofemoral (axial) view to evaluate for patellar fractures and degree of subluxation 1
• Order MRI after initial radiographs to characterize associated injuries including osteochondral fractures, bone marrow contusions, and ligamentous injuries (particularly medial patellofemoral ligament damage, which occurs in 96-100% of dislocations) 1, 2

First-Line Treatment: Nonoperative Management

Functional support is strongly preferred over rigid immobilization and should be the default approach for most patients 1:

• Use an ankle-style functional brace for 4-6 weeks, as braces show the greatest treatment effects compared to other types of functional support 1
• If immobilization is necessary for severe pain or edema, limit it to a maximum of 10 days, then transition to functional support 1
• Approximately 60-70% of patients respond well to nonoperative treatment, making this the appropriate initial approach for most cases 1

Key principle: Avoiding unnecessary surgery reduces risks of complications, ankle stiffness, and impaired mobility 1

Indications for Surgical Intervention

Surgery should be considered in specific circumstances:

Absolute Indications:

• Osteochondral fractures identified on imaging 1
• Significant concomitant injuries requiring surgical repair 1

Relative Indications:

• Recurrent lateral patellar dislocations despite adequate nonoperative management 2, 3
• Professional athletes who may benefit from earlier surgical intervention to ensure quicker return to play 1
• Chronic fixed lateral patellar dislocation that has failed conservative management 4

Surgical Options for Recurrent Dislocation

When surgery is indicated, medial patellofemoral ligament (MPFL) reconstruction is the primary procedure, as the MPFL is the primary static restraint to lateral patellar translation and is injured in 96-100% of patellar dislocations 2:

MPFL Reconstruction Techniques:

• Double-anchor anatomic reconstruction technique may be more effective than single-bundle transpatellar tunnel technique, achieving better patellofemoral joint congruence and knee function 3
• Both techniques achieve good results with recurrent instability rates of 1-5% 2, 3
• Critical technical point: Reproduction of the anatomy and isometry of the native ligament is essential for success 2

Additional Procedures to Consider:

• Extensive lateral release may be combined with MPFL reconstruction in chronic fixed lateral dislocations 4
• Combined MPFL and medial patellotibial ligament reconstruction should be considered for lateral patellar dislocation occurring specifically in flexion, as the medial patellotibial ligament provides stability at higher degrees of knee flexion 5
• Tibial tubercle osteotomy, trochleoplasty, or derotation osteotomy may be combined with MPFL reconstruction based on specific anatomic risk factors 6

Risk Factors Requiring Attention

Identify these anatomic risk factors that increase dislocation risk and may influence treatment decisions 2:

• Patella alta
• Trochlear dysplasia
• Genu valgus
• Increased Q angle
• Hyperlaxity

Common Pitfalls to Avoid

• Avoid rigid immobilization as first-line treatment unless severe pain/edema necessitates it, and even then limit to 10 days maximum 1
• Do not rush to surgery for first-time dislocations without osteochondral fractures, as 60-70% respond to conservative treatment 1
• Ensure proper surgical technique to avoid complications including fracture, graft failure, loss of range of motion, persistent anterior knee pain, and recurrent instability 2
• Do not overlook MRI evaluation after initial radiographs, as it characterizes critical soft-tissue and bone injuries that influence treatment decisions 1