MPFL Reconstruction Surgery
The medial patellofemoral ligament is a short band running from the inner side of the kneecap to the thigh bone, and its job is narrow but important. It resists the kneecap sliding outward. When it tears, which it does in nearly every kneecap dislocation, the main restraint against a repeat dislocation is gone.
An MPFL reconstruction addresses the ligament that keeps the kneecap tracking correctly, and it is usually considered after a dislocation has happened more than once. Steven Struhl, MD is board certified in orthopedic surgery and separately in sports medicine and arthroscopic surgery, completed his sports medicine fellowship at Penn State University, and has performed more than 5,000 arthroscopic procedures.
Why the MPFL Matters
The kneecap sits in a groove at the end of the thigh bone and is held there by the shape of that groove, by the pull of the quadriceps, and by the MPFL. In a first time dislocation, the MPFL is torn in the great majority of cases.
- Primary Restraint: the MPFL provides most of the resistance to outward kneecap movement.
- Torn In Most Dislocations: the ligament fails as the kneecap displaces laterally.
- Poor Healing: it frequently heals loose rather than at its original length.
- Recurrence Driver: a lax MPFL is why a second dislocation follows a first so often.
Who Is a Candidate
- Recurrent Dislocation: the kneecap has dislocated more than once.
- Persistent Instability: the kneecap gives way or subluxes during normal activity.
- Failed Rehabilitation: an appropriate strengthening program has not restored stability.
- High Risk Anatomy: a shallow groove or high riding kneecap raising the recurrence risk.
A first time dislocation in a patient with normal anatomy is usually treated without surgery, since a meaningful share never dislocate again. Recurrence changes that calculus substantially.
How the Reconstruction Is Performed
The torn ligament is not repaired, it is replaced. A tendon graft, most often a hamstring tendon, is passed from the inner border of the kneecap to its attachment point on the thigh bone and fixed at the correct length and tension.
Getting that tension right is the entire operation. Too loose and the kneecap remains unstable. Too tight and the kneecap is pulled hard against the inner side of the groove, which causes pain and can damage cartilage. The graft is tensioned to restrain the kneecap rather than to pull it.
Additional Procedures
An MPFL reconstruction is sometimes performed alone and sometimes alongside procedures addressing the underlying anatomy.
- Tibial Tubercle Osteotomy: repositioning the attachment of the patellar tendon.
- Trochleoplasty: deepening a shallow groove, reserved for severe cases.
- Cartilage Treatment: addressing damage caused during the dislocations themselves.
- Lateral Release: loosening tight tissue on the outer side, used selectively.
Recovery
- Weeks One To Two: a brace protects the graft, with weight bearing as tolerated.
- Weeks Two To Six: progressive motion, with flexion increased gradually.
- Months Two To Four: quadriceps and hip strengthening, which drives the outcome.
- Months Four To Six: return to sport, guided by strength testing rather than the calendar.
Schedule a Knee Evaluation in New York City
A kneecap that has dislocated more than once is unlikely to settle on its own, and each episode carries a risk of cartilage damage that outlasts the instability. Dr. Struhl evaluates patellar instability at his Manhattan and White Plains offices. Contact the practice to schedule an appointment.
