The aim of every therapy of a patella dislocation is to center the patella permanently around sliding bearings, since valuable cartilage mass is lost with every dislocation event. Since cartilage tissue is not capable of regeneration, the amount of cartilage provided by birth must be handled with care. The more frequently a patella dislocation occurs, the higher the probability of premature patella arthrosis (retropatellar arthrosis).
An acute patella dislocation must be reduced immediately. Optionally, a follow-up treatment in a thigh cast can follow. If cartilage shearing (flake) is suspected or confirmed by an MRI examination, arthroscopy (knee endoscopy) should be performed to assess the extent of the cartilage damage.
If a flake is found, it should be refixed if possible. For this purpose, the knee joint must be opened and the sheared fragment re-fixed in its place so that no cartilage sliding surface is lost. In case of multiple patellar dislocations, surgical correction of the patella should be performed.
In this case, various corrective operations can be considered. The most frequently performed operations are listed below. Basically, a distinction is made between soft tissue surgery (ligament tightening and suturing) and bony corrective measures when operating on patella dislocation. Bony corrective measures should only be carried out after growth has been completed.
Insall surgery
In this surgical method of a patellar dislocation, the inner capsule is gathered; in a traumatic initial dislocation, the inner capsule apparatus (medial retinaculum) is sutured simultaneously. This measure is intended to shift the course of the patella more to the inside of the knee joint to prevent a renewed external dislocation. This surgical method can be combined with a lateral release. In this case, ligament structures on the outside of the kneecap are cut in order to reduce the lateralization tendency of the kneecap. Many other methods are described in the literature.
Tuberosity dislocation
As a bony corrective measure, the relocation of the insertion of the patellar tendon can be considered. Operation according to Elmslie-Trilat: In this operation, the attachment of the patellar tendon (patella tendon) on the tibia (tuberosity tibiae) is displaced inwards (medially). This displacement causes the patella to move further inwards in its glide path, which makes dislocation much more difficult. This procedure can be combined with soft tissue surgery (e.g. insall surgery).
