Patella Dislocation Reduction: Initial Approach
Perform immediate closed reduction of an acute patella dislocation in the emergency department or prehospital setting using gentle extension of the knee with medial pressure on the lateral patella, which provides significant pain relief and has minimal complications. 1
Immediate Reduction Technique
- Apply gentle knee extension while applying medial pressure to the laterally displaced patella to achieve reduction 1
- Reduction can be performed by EMS providers in the prehospital setting with a 92% success rate and no reported complications 1
- Median pain scores decrease dramatically from 10/10 to 2/10 following successful reduction 1
- Most acute traumatic patella dislocations reduce with this simple maneuver 2
Pre-Reduction Imaging Considerations
- Obtain radiographs BEFORE reduction attempts only if there is gross deformity, palpable mass, or concern for associated fracture 3
- In straightforward lateral dislocations without these concerning features, proceed directly to reduction for pain relief 1
- The standard approach includes anteroposterior and lateral knee radiographs, with a patellofemoral (axial) view to evaluate for patellar fractures or subluxation 3
Post-Reduction Management
Obtain post-reduction radiographs to confirm successful reduction and evaluate for osteochondral fractures, which occur in a significant proportion of cases and may alter management 2
Post-Reduction Imaging Protocol:
- Minimum two views (anteroposterior and lateral) are required 3
- Add patellofemoral view to assess patellar tracking and identify loose bodies 3
- Consider MRI without IV contrast if radiographs show osteochondral fragments or if there is persistent effusion, as MRI can identify cartilage injury, medial patellofemoral ligament disruption, and loose bodies not visible on radiographs 3
When Closed Reduction Fails
If initial closed reduction attempts are unsuccessful, prepare for open reduction under general anesthesia rather than repeated forceful attempts 4, 5
Indications for Open Reduction:
- Failed closed reduction after 1-2 gentle attempts 4, 5
- Intra-articular dislocation with rotation (rare but requires open approach) 4, 5
- Patella locked in intercondylar or superior position 6, 5
- Palpable interposed soft tissue preventing reduction 5
Critical Pitfall:
- Do not perform multiple forceful reduction attempts, as this increases risk of iatrogenic injury 5
- Rare rotational dislocations (vertical axis rotation) will not reduce with standard techniques and require operative intervention 5
- Spontaneous reduction can occasionally occur even after failed attempts, but delaying definitive treatment is not advisable 4
Subsequent Treatment Decision-Making
Initial nonoperative management is recommended for most first-time traumatic dislocations EXCEPT in specific circumstances 2
Indications for Surgical Intervention:
- Presence of osteochondral fracture on imaging 2
- Substantial disruption of medial patellar stabilizers visible on MRI 2
- Laterally subluxated patella with normal alignment of contralateral knee 2
- Second dislocation episode 2
- Failure to improve with appropriate rehabilitation 2