Treatment of Recurrent Subluxation or Dislocation of the Patella

The treatment of patellofemoral joint subluxation depends on the following factors.

• Degree of lateral displacement of the patella
• Mechanism or type of subluxation or dislocation-whether it is due to
  • Malalignment of the quadriceps mechanism with contracture of the lateral patellar retinaculum and iliotibial band.
  • Muscle imbalance between a weak and high oblique vastus medialis and a hypertrophied, low, and transverse vastus lateralis
  • Extreme ligamentous hyperlaxity
  • Trauma resulting  weakening of the vastus medialis.
  • Malposition of the patella
  • Angular or rotational deformity of the knee and leg
  • Presence or absence of bony hypoplasia of the lateral femoral condyle.

• Presence or absence of chondromalacia of the patella.
• Age
• Psychological aspects

A rough guide to management of this condition is as follow

Congenital Dislocation of the Patella

Causative Factors

• Marked soft-tissue contracture of the lateral side of the knee
• Malalignmnet and contracture of the quadriceps mechanism
• Secondary developmental structural changes
  • Shallow femoral sulcus
  • Hypoplasia of the patella.

Treatment

• Surgical replacement of the patella in the femoral sulcus by
  • Release and lengthening of all lateral contracted soft-tissue structures
  • Tautening of the medial capsule and retinaculum
  • Distal and lateral advancement of ht evastus medialis
  • Tenodesis of the semitendinosus to the patella
  • Shortening of the patellar tendon by distal-medial transfer.

Chronic Developmental Subluxation or Dislocation

These are  associated with

• Severe ligamentous hyeprlaxity
• Genu valgum
• Hypoplasia of the lateral femoral condyle.
• Patella alta may be present
• Contracture and malalignment of the vastus lateralis
• High insertion and hypoplasia of the vastus medialis.

Treatment

• Surgical relocation of the patella
• Realignment of the quadriceps muscle
• Tenodesis of the semitendinosus tendon to the patella  if Patella Alta is there.

Post-Traumatic Recurrent Lateral Subluxation or Dislocation

The great majority of acute patellar dislocations are lateral; ocasssionally, however, they may be medial, intra-articular, or superior.

Acute dislocations associated with osteochondral fracture require surgical treatment. The fragment is removed or reattached along with soft tissue repair.

Nonoperative management is followed if examination of the aspirated blood from the knee does not show fat droplets and there is no evidence of osteochondral fracture.

In doubt, perform diagnostic arthroscopic examination.

Nonoperative treatment

• Immobilization of the knee in an above-knee cylinder cast for three to four weeks
• Rehabilitation exercises for the quadriceps and hamstrings after that.

Recurrent post-traumatic dislocations require surgical intervention.

Recurrent post-traumatic subluxations an initial period of conservative management should always be tried.If it fails, operative treatment is indicated

• Release of the lateral patellar retinaculum and vastus lateralis
• Tautening of the medial capsule and medial patellar retinaculum
• Distal lateral transfer of the vastus medialis.

Patellar Subluxation with Lateral Pressure Syndrome

The initial treatment should be nonsurgical, particularly when the associated chondromalacia is not severe. The non operative treatment includes

• Exercises  restore motor strength of the quadriceps femoris, and especially  vastus medialis.

The exercises should be isometric. Isotonic exercises should not be performed, as they markedly increase the patello-femoral load.

• Hamstrings exercise
• Descending and climbing stairs, bicycle riding, contact sports, and other strenuous physical activities are curtailed.
• Analgesics and antiinflammatory drugs

Operative measures are carried out when conservative management fails to relieve .