What is patella dislocation?

The reason for lateral patella dislocation (LPD) can be affected by both primary and secondary factors. The primary instability factors have been identified as trochlear dysplasia, excessive tibial tubercle-trochlear groove (TT-TG) distance and patella alta (1). The secondary factors include femoral anteversion, excessive lateral tibial torsion, recurvatum and genu valgum. These factors may  impact on which type of surgery is indicated.

The vast majority of patella dislocations occur in a lateral direction.

What is medial patellofemoral ligament (MPFL) surgery?

In case of patella dislocation, surgery can be indicated after recurrent patella dislocations if no satisfactory results have been achieved through conservative treatment (2,3,).  It is often debatable how many dislocation that need to happen before surgery is offered. The purpose of this type of surgery is to provide a stabilizing effect of the patella, providing medial restraining forces to prevent redislocation. However, with the literature, many  different surgical techniques has being used.

Some of the more commonly used surgical techniques is categorize in three groups: 1) MPFL reconstruction with autologous graft (Gracilis), 2) MPFL medial structures repair (with Plication), 3) MPFL reconstruction combined with tibial tubercle transfer osteotomy (TTTO) (Hauser or Fulkerson). The most commonly a semitendinosus or gracilis autograft is used through a tunnels or interference screws.

History and injury mechanism

The patient often describes a sudden pain with a rotation activity, combined with a feeling of a pop or something going out of place. It is important to ask for how long this patella was displaced it was “pop” or pushed in again.

There may be a history of generalized ligamentous laxity/other dislocations. The injury can also follow from an acute trauma. When the patella is dislocated or tendon ruptured it will be a visible trauma.

Patella dislocation (specially first-time) can sometimes be treated conservative, opposite a rupture of the patella tendon must be surgical repair followed a intensive rehabilitation.

Many Danish spectators still remember Henrik Andersen Patella dislocation trauma in the UEFA Euro 1992 Semi–finals between Denmark and Holland. A tournament which has been call and properly ever will be the biggest Danish sports sensation.

Rehab considerations

After MPFL reconstruction rehabilitation can take up to 1 year to normalization knee kinematics and return to normal gait.

There is no consensus on return to sport timeline or criteria, however it has been suggested that adolescent athletes undergoing MPFL reconstruction might need prolonged rehabilitation beyond 8 months (7, 8).

Weightbearing after MPFL reconstruction varies and is based on surgeon preference. Range of motion should be unaffected by axial load and limitation in weight bearing as long as rotation of the joint is restricted. Usual full weightbearing as tolerated with brace for two weeks. In case of tibial tubercle transfer osteotomy weightbearing and brace need to be consider accordingly to surgical guidelines.

Ask for D-vitamin defiency in relation to bone and soft tissue healing.