Table 2.

Pearls, Pitfalls, and Risks

Pearls

The present patellofemoral ligament reconstruction technique is a simple soft tissue procedure in which the femoral physeal plate is not affected as no tunnel needs to be drilled and no hardware to fix the graft to the bone needs to be used.

Save the tendon in a gauze soaked in vancomycin to reduce the risk of infection.

The doubled gracilis graft should be at least 90 mm.

In the proximal two-thirds of the patella, drill 2 convergent holes avoiding inserting the graft distally to the native insertion of the MPFL to avoid constraint of the distal patellar pole.

Leave a cortical bone bridge of 10 mm between the tunnels to avoid a fracture.

Use a dissector-clamp for soften the “killer angle.”

Once the adductor magnus tendon is identified, gently dissect around it, freeing all interdigitations of the tendon down to its insertion, as distal as possible, as it better approximates the anatomic femoral insertion point of the MPFL.

The graft is passed through the patella and placed in the interval between layers 2 and 3 of the medial retinaculum. Placing the graft between layers 2 and 3 is preferred for 2 reasons. First, the vastus medialis inserts superficially into the anterior 3 cm of the MPFL, so blind dissection superficial to the MPFL may cause unnecessary trauma to this insertion. Second, if the graft is placed deep into the MPFL, the native MPFL may be repaired to the graft during wound closure.

Tension was calculated on the basis that the patella could still be manually lateralized some 10 mm to avoid overconstraint. The lower limb was finally immobilized in a brace locked at full extension.

Pitfalls and Risks

Overtightening of the graft so that the graft is under tension when the patella is in contact with the medial trochlea facet will result in an overconstrained patella that is painful, and could lead to arthrosis as a result of increased medial facet forces.

Avoid fixing the graft distally to the native insertion of the MPFL to avoid constraint of the distal patellar pole.

During preparation of the 2 patellar tunnels, or during passage of an oversized tendon graft through a tight patellar tunnel, the bone bridge overlying the patellar tunnel may break.

Stiffness can occur if the patient is not able to follow the established rehabilitation protocol. Partial weight bearing with a knee brace lock at full extension is allowed immediately postoperation and progressed to full weight bearing without the brace at approximately 4 weeks. Passive unrestricted range of motion is allowed after 2 weeks.

MPFL, medial patellofemoral ligament.