When is surgery indicated?
Surgery is typically considered after two or three dislocations, or earlier if there is significant cartilage or bone damage from the dislocations.
MPFL reconstruction
The medial patellofemoral ligament is the primary soft-tissue restraint preventing the patella moving outwards. When stretched or torn, it can be reconstructed using a hamstring tendon graft.
- Three small incisions — one over the kneecap, one over the inner femur and one at the hamstring harvest site.
- The graft is fixed to the patella using small bone anchors and to the femur with an interference screw.
- Combines very well with arthroscopic surgery to deal with any associated cartilage damage.
Tibial tuberosity osteotomy
When the alignment of the tibial tuberosity (where the patellar tendon attaches to the tibia) is too far to the outside, the tuberosity can be repositioned through an osteotomy.
- A 5–8 cm incision over the front of the tibia.
- The tibial tuberosity is cut from the front of the tibia and moved to a more central position.
- It is fixed in place with two or three screws.
Recovery
- 0–6 weeks: reducing swelling, regaining range of motion, protected weight-bearing.
- 6 weeks onwards: progressive strengthening.
- 4–6 months: return to sport for most patients.
Success rate
Patella stabilisation surgery has a 90–95% success rate in preventing further dislocations.
Risks
Risks include infection, recurrent dislocation, stiffness, fracture of the tibial tuberosity in osteotomy procedures, nerve injury and ongoing anterior knee pain.