Patellar Instability

Patellar instability occur when the patella, or knee cap is displaced from its resting place.

Causes

 

  • A hand blow or a fall
  • Traumatic ligament laxity
  • Atraumatic

 

Patellar instability can be classified into

 

  • Acute traumatic
  • Occur after a direct blow – collision in the foots or hit against a hard surface during a fall
  • Chronic recurrent subluxation episodes occur more in women associated with maliagments
  • Habitual-usually painless
  • Occur during flexion
  • Could be because of tight lateral structures like ITB, vastus laterials

Symptoms

 

  • Instability
  • Anterior knee pain
  • Medial side tenderness
  • Patella apprehension

 

Diagnosis

 

Clinical pattelar apprehension test.

 

Imaging

 

  • MRI- To rule out
  • MPFL team
  • Trochlea hypoplasia
  • Osteochondrol lesion/ or bone brushing on medial patellar facet

 

Treatment

 

Non operative

 

  • Acute dislocation – immobilization in cast for 3 week followed by supervised rehab for 6 weeks. Main emphasis on VMO strengthning with ITB release.
  • Patellar stabilizing brace.

 

Operative

 

MPFL repair- if no significant underlying malaligment. Tibial tubercle transfer is done in addition to MPFL reconstruction or in isolation with significant malaligment.