MPFL reconstruction and tibial tubercle osteotomy to restore patellar stability and allow return to sport.
The patella (kneecap) sits in a groove at the front of the femur called the trochlear groove. Normally it tracks smoothly through this groove during knee movement, held in place by a combination of bony anatomy, cartilage, and soft-tissue restraints. In some patients — particularly after a patellar dislocation — one or more of these restraints are disrupted, leading to recurrent dislocation or a persistent feeling of giving way. The medial patellofemoral ligament (MPFL) is the primary soft-tissue restraint preventing lateral patellar dislocation. It is torn in virtually all first-time patellar dislocations.
Not all patients with patellar instability require surgery. Those with a single dislocation are often managed non-operatively with physiotherapy and bracing. Surgery is recommended for patients with: recurrent patellar dislocation; significant anatomical risk factors (trochlear dysplasia, patella alta, or a lateralised tibial tubercle); failure of conservative management; and younger, active patients who are at high risk of further dislocation.
MPFL reconstruction rebuilds the medial patellofemoral ligament using a graft. Dr Mooney uses the gracilis tendon onlay technique: the gracilis tendon is harvested from the inner thigh, folded, and secured to the medial border of the patella using small anchors, then passed to a fixation point on the femur at the isometric point for MPFL. This technique avoids tunnels through the patella (which can risk patellar fracture) and produces reliable, reproducible stability. The surgery is performed under general anaesthetic and takes approximately 60–90 minutes.
In some patients, the tibial tubercle — the bony bump where the patellar tendon inserts — is positioned too far laterally, pulling the kneecap outward during knee movement. This is measured on MRI using the tibial tubercle to trochlear groove (TT-TG) distance. If this distance is elevated (typically greater than 20mm), a tibial tubercle osteotomy (TTO) is recommended in addition to MPFL reconstruction. TTO involves cutting the tibial tubercle and moving it medially (anteromedialisation) to improve patellar tracking. In patients who also have patella alta (a high-riding kneecap), the tubercle can be moved distally at the same time (distalisation) to bring the patella into better contact with the trochlear groove. This is performed under the same anaesthetic as MPFL reconstruction in most cases. The osteotomy is fixed with screws and heals over 6–8 weeks.
For a first-time dislocation, physiotherapy is the recommended first step. It can improve muscle balance around the knee and reduce the risk of re-dislocation. However, if structural risk factors are present or the knee continues to dislocate, surgery is usually required.
Not always. Dr Mooney assesses each patient individually using MRI measurements, clinical examination, and your history of instability. Some patients require MPFL reconstruction alone; others benefit from adding a TTO.
Return to sport typically takes 4–6 months. Recovery after a combined procedure (MPFL + TTO) is a little longer than MPFL alone, due to the healing time required for the bony osteotomy.
Crutches are available for support after surgery but are not essential — full weight bearing in a brace is allowed from Day 1. Most patients find they need crutches for comfort in the first week or two, then discard them as their confidence and strength return. The brace is worn for 6 weeks in total.
As with all surgery, risks include infection, bleeding, deep vein thrombosis, and anaesthetic risks. Specific risks include stiffness, failure of the MPFL graft, patellar fracture (rare with the onlay technique), non-union of the osteotomy, and recurrent instability. Dr Mooney will discuss these with you in detail at your consultation.
Dr Luke Mooney is an Adelaide orthopaedic surgeon who has built his practice around hip, knee, and sports injury surgery. He holds the qualifications MBBS, FRACS, and FAOrthA, and is a Clinical Senior Lecturer at the University of Adelaide.
When you see Dr Mooney, you see Dr Mooney — at every appointment, at surgery, and at every follow-up.
About Dr Mooney →Call the rooms or submit an online enquiry. A GP referral is required for Medicare rebate purposes.