Patella Instability and Dislocation

  • Group discussion on patellar instablity 
  • YouTube Video

    A common symptom of patellar injury and dislocation is acute pain after direct contact or sudden change of direction (ie, a cutting maneuver). With sudden changes in direction, the femur medially rotates over the ground-stabilized tibia. Under these conditions, athletes commonly feel the knee giving way, which is the result of quadriceps inhibition from pain, a physiologic protective mechanism. Rapid swelling, intense knee pain, and difficulty with any knee flexion usually occur.
  • Symptoms may also manifest as a slowly progressive sensation of anterior knee pain with increased physical activity. Intense physical activity increases JRFs across the knee. Such activities include inclined ambulation, squatting, prolonged sitting, and going up and down stairs. Anterior knee pain aggravated by activity is typical of chondral pathology.
  • A common symptom in nontraumatic patellofemoral problems is crepitus of the patellofemoral joint.

Surgical Intervention

Surgical intervention may be appropriate in 2 different patient populations: (1) those with normal anatomy who experience recurrent dislocation or pain and (2) those with an anatomic abnormality who may benefit from surgical intervention either upon initial acute dislocation or later with recurrence of dislocation or subluxation. In general, following acute patella dislocation, patients with normal lower extremity anatomy and without radiographic indications of intra-articular injury are best served by conservative treatment. 

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Proximal procedures
Acute case: MPFL repair.
Chronic case: MPFL reconstruction.
  • Medial repair
    • This group includes 3 primary procedures, all of which attempt to recreate an appropriate physiologic mechanism at the knee joint by improving the integrity of the structures that provide medially directed forces on the patella. The techniques include (1) plication of the medial patellar retinaculum, (2) anatomic repair of the MPFL, and (3), plasty surgery of the VMO.
    •  MPFL and the VMO are the primary restraints to lateral patella translation, particularly early in flexion before full trochlear engagement.

    • Lateral release: Should be done in very very selected cases.

Distal procedures

  • Tibial tubercle transfers
    • Tibial tuberosity trasfer should be restricted to patients with Increased TT TG distance. Rigid, distal procedures are associated with increased rates of progressive retropatellar arthrosis but lower rates of redislocation . Hence in patient with preexicting arthrosis better to do an anetromedialisation as compared to only medialisation.
    • Surgeon can plan either a medialisation or an anteromedialisation depending on the symptoms.
  • Combined procedures
    • can be used in severe cases. 
  • Trochleoplasty: A promising technique for selected cases.
  • It is of 2 types Open trocleoplasty  and arthroscopic trocheoplasty.

X ray picture suggestive of a complex surgery in which Fulkersson osteotomy was done along with medial augmentation and lateral release


MPFL advancement : this is a procedure developed at advance knee and shoulder hospital. This procedure prevents the many issues and problems of MPFL reconstruction surgery . MPFL is not a actual ligament but a capsular thickening.This techniques incorporates this principle and advance the capsular layer on the patella using 2 anchors on the medial surface of the patella. This leads to adequate tensioning of the patella and a strong medial check rein effect.

 
















                             MPFL tear in an acute injury.
                             First episode of dislocation , treated with acute MPFL      repair with 2 suture anchors. This is an innovative technique developed at advance knee and shoulder hospital. This procedure is particularly used for first time dislocation of the patella. MPFL tear is usually from patellar side.







After its success in acute cases we have starting using the same technique for chronic patellar instablity cases as well. The technique is due for publication. We do athrough MPFL repair after a sequentila release from patella. the fixation is done with 2 suture anchors on superomedial aspect of patella 







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