MPFL Reconstruction

If your kneecap has dislocated — once with concerning anatomy, or repeatedly — the question is rarely whether the MPFL is torn (it almost always is, after a true dislocation) but whether your knee will benefit more from formal reconstruction or from continued non-operative management with bracing and physical therapy. The answer depends on how often your kneecap dislocates, what your imaging shows about the underlying bony architecture, and whether the cartilage on the back of the patella or in the trochlear groove has been damaged. MPFL reconstruction is the soft-tissue side of patellar stabilization; for a meaningful proportion of patients, the bony alignment also has to be addressed.

This page covers what MPFL reconstruction restores, when it is and is not the right operation, the clinical decision between MPFL alone and MPFL combined with TTO, why graft and fixation choices matter less than commonly assumed and where they still matter, what to expect on surgery day and through recovery, the risks of the procedure, and when a sub-specialty second opinion is worth seeking — particularly for failed prior MPFL reconstruction. For closely related topics, see patellar instability for the broader diagnostic framework; joint preservation and osteotomy for TTO and HTO/DFO realignment; MACI cartilage repair when patellar cartilage damage is part of the picture; and patellar pain and patellar arthritis when chronic patellofemoral cartilage wear has set in.

What MPFL Reconstruction Restores

The medial patellofemoral ligament is a flat, fan-shaped structure on the inner side of the knee that runs from the medial epicondyle of the femur to the upper-medial border of the patella. Functionally, it acts as a leash — in the first 30 degrees of knee flexion, before the patella seats into the deeper part of the trochlear groove, the MPFL is the primary restraint that prevents the kneecap from being pulled laterally out of the groove.

After a patellar dislocation, the MPFL is almost always torn. Even when the kneecap relocates spontaneously (which it usually does), the soft-tissue restraint is gone. With the leash damaged, the kneecap can dislocate again with much less force than it took the first time — often during ordinary activity rather than a high-energy injury.

MPFL reconstruction restores that lateral restraint with a tendon graft anchored between the patella and femur. The graft does not heal back into a native MPFL — it functions as a check-rein that prevents the kneecap from tracking too far laterally during the early flexion arc, which is when the joint is most vulnerable. When MPFL reconstruction is paired with the right bony correction in patients who need it, the rate of recurrent dislocation falls substantially.

How an Instability Episode Feels

A first dislocation is usually distinct:

• The kneecap visibly slips off-center — toward the outer side of the knee — sometimes with an audible pop
• Sharp pain on the inner side of the knee where the MPFL has just torn
• Rapid swelling within hours (a hemarthrosis — blood in the joint), particularly if a piece of cartilage has chipped off the patella or trochlea
• The kneecap usually relocates on its own when the knee is straightened, sometimes with a second pop, sometimes spontaneously
• Difficulty bearing weight or straightening the knee, especially if a loose osteochondral fragment is blocking motion

Recurrent instability often feels different. Once the MPFL has failed and the underlying anatomy is unfavorable, subsequent episodes can occur with progressively less force — turning to talk to someone, stepping out of a car, going down a curb at an angle. Many patients describe a chronic sense of the kneecap "wanting to slip out," guarding against twisting motions, and a loss of confidence in the knee that affects sport, work, and even routine walking on uneven ground.

An acute dislocation with a loose osteochondral fragment is a different scenario: the knee is often locked, swollen, and weight-bearing is difficult. These patients typically need urgent imaging and may need to go to the operating room sooner to address the fragment, with or without an MPFL reconstruction in the same sitting.

The Surgery Decision

Whether to reconstruct the MPFL depends on:

• How many times the patella has dislocated — recurrent dislocators almost always benefit from reconstruction; first-time dislocators with multiple risk factors for recurrence (younger age, trochlear dysplasia, patella alta, elevated TT-TG distance, generalized ligamentous laxity) often do as well
• Imaging findings — trochlear shape, patellar height, TT-TG distance, status of the MPFL, presence of an osteochondral fragment or focal cartilage damage
• Activity goals — the more the knee is asked to cut, pivot, and rotate, the lower the threshold for reconstruction
• Failure of conservative care — structured physical therapy focused on quadriceps and hip strength, neuromuscular control, and bracing for higher-risk activity; when the knee continues to dislocate or persistently feels unstable despite a fair non-operative trial, reconstruction is indicated
• Loss of confidence and quality of life — even between dislocations, many patients lose the ability to participate fully in their sport, work, or daily activity because of the fear of giving way

For patients who are not surgical candidates — or who choose to proceed non-operatively — structured PT is the foundation. Quadriceps activation, hip and core strengthening, neuromuscular control, and (in selected cases) a patellar stabilization brace can substantially reduce the rate of recurrent episodes. The trade-off is that without surgical correction of the soft-tissue restraint and any contributing bony malalignment, the kneecap remains at higher risk of dislocating again, and each dislocation carries the potential for additional patellar or trochlear cartilage damage.

MPFL Alone vs. Combined with TTO

This is one of the most important decision points on the page, and it is genuinely sub-specialty work. MPFL reconstruction alone is sufficient for many patients with recurrent dislocations. A subset of patients have bony anatomy that means the soft-tissue reconstruction alone will be biomechanically asked to do more than it should — and in those patients, combining the MPFL reconstruction with a tibial tubercle osteotomy (TTO) addresses the bony alignment that is contributing to the instability.

The decision is based on imaging measurements and physical examination, not symptoms alone. The features that push toward adding a TTO are:

• Significant patella alta — a high-riding kneecap that does not engage the trochlear groove until later in flexion than it should. Measured on lateral X-ray with the Caton-Deschamps or Insall-Salvati ratio. Distalization of the tibial tubercle brings the kneecap down into earlier engagement
• Elevated TT-TG distance — the tibial tubercle (where the patellar tendon attaches to the tibia) is too far lateral relative to the trochlear groove. Measured on CT or MRI. Medialization of the tibial tubercle redirects the line of pull on the kneecap medially
• Severe trochlear dysplasia — a shallow or convex trochlear groove that does not provide a containing track for the kneecap. In selected severe cases, trochleoplasty (deepening the groove) may also be considered

When these bony factors are missed at the index surgery, the MPFL graft is asked to substitute for both the soft-tissue restraint and the missing bony containment — a setup for recurrent instability or for the graft to stretch out over time. Unaddressed bony risk factors are one of the most common causes of failed MPFL reconstruction, which is why imaging-guided patient selection matters so much.

For more on the specific decision-making and patient stories, see Dr. Strickland's MPFL reconstruction and TTO questions post and the joint preservation and osteotomy page for the full TTO walk-through.

Graft and Fixation Choices

Two technical decisions get a lot of attention in MPFL reconstruction discussions: which graft, and how the graft is fixed to the patella. Published evidence suggests graft choice has relatively little effect on outcomes — gracilis allograft, hamstring autograft, and quadriceps tendon all produce comparable results when matched to the right patient. Patellar fixation, on the other hand, is where Dr. Strickland's technique preferences are explicit and worth understanding.

For the published reasoning behind the two-point patellar fixation preference, see Dr. Strickland's editorial commentary on two fixation points in The Journal of Arthroscopic and Related Surgery.

What about robotic-assisted MPFL reconstruction?

A published study compared robotic-assisted versus freehand MPFL reconstruction. The robotic-assisted group did achieve a femoral tunnel that was on average closer to a specific anatomic landmark, but both groups had similar rates of clinically meaningful patient-reported outcomes. The robotic-assisted surgery took longer and required expensive technology, and as Dr. Strickland has noted, anatomic variation between patients means that a single "standard" tunnel position is not always the correct one for an individual patient. For most cases, experienced freehand technique with intraoperative verification of landmarks with x-ray (fluoroscopy) is the approach of choice. See her commentary on robot-assisted vs. freehand MPFL reconstruction for the full discussion.

Concurrent Cartilage Repair

A patellar dislocation is rarely just a soft-tissue event. As the patella shears off the trochlear groove and then snaps back into place, the cartilage on the back of the patella and along the lateral wall of the trochlea can be damaged. This shows up on MRI as a bone bruise pattern at minimum, and in some cases as a frank osteochondral lesion or a loose fragment in the joint.

When focal cartilage damage is present, MPFL reconstruction is often combined with a cartilage procedure in the same operation:

• Loose fragment fixation or removal — for displaced osteochondral fragments after acute dislocation
• MACI (matrix-induced autologous chondrocyte implantation) — a two-stage procedure where cartilage cells are harvested from the patient at the index surgery, grown in a lab, and implanted at a second surgery onto a focal patellar or trochlear cartilage defect. See MACI cartilage repair for the full walk-through
• DeNovo (donor juvenile cartilage) — a one-stage procedure for small cartilage lesions
• Osteochondral autograft (OATS) — for smaller lesions that include subchondral bone
• Osteochondral allograft (OCA) — for larger lesions that include subchondral bone

When chronic patellofemoral cartilage wear has progressed beyond focal repair territory, the conversation shifts to patellar pain and patellar arthritis management — which can include alignment correction, patellofemoral arthroplasty in selected cases, and the full menu of biologic and surgical options for chronic patellofemoral disease.

Prehabilitation

For elective MPFL reconstruction in patients with chronic instability, prehabilitation matters. Dr. Strickland recommends starting prehab 4 to 6 weeks before surgery. The goals are full pain-free range of motion, strong quadriceps activation, and good hip and core control. Patients who arrive at surgery with a quiet, mobile knee and active quads regain motion and strength faster after the operation than patients who arrive with a stiff, swollen, quad-inhibited knee.

A productive prehab phase typically includes:

• Working with a physical therapist who has knee or sports medicine expertise — ideally one who has worked with patellar instability patients before
• Familiarizing yourself with the planned post-operative rehab protocol so the first few weeks after surgery are not surprising
• A home exercise program built around quad sets, straight-leg raises, hip and glute work, and gentle range of motion within pain-free limits
• An up-to-date medication and supplement list reviewed with your surgical team and primary care physician — some anti-inflammatories, blood thinners, and supplements may need to be paused before surgery
• A plan for transportation home, post-op support at home, and time off from work or school

Acute dislocations with a locked knee or a loose osteochondral fragment do not get this 4 to 6 week window — those patients need to go to the operating room sooner. For those patients, the prehab framing changes to managing pain and swelling, gentle quad sets if possible, and getting to surgery quickly. For more, see Dr. Strickland's how to prepare for an MPFL reconstruction guide.

What to Expect on Surgery Day

MPFL reconstruction is performed as an outpatient procedure — you go home the same day. This is the typical patient experience and your specific protocol is reviewed at consultation:

• Arrival and pre-op — you arrive a couple of hours before the procedure for intake, change into a gown, and meet the anesthesia team
• Anesthesia consultation — the anesthesiologist reviews your history and discusses the anesthesia plan. For Dr. Strickland's MPFL reconstructions, this is typically regional anesthesia (a spinal block with sedation) rather than general anesthesia. During surgery, a periarticular block is also placed around the knee joint to help reduce pain during the first day after surgery as part of an opioid-sparing pain protocol; if a TTO is added, the protocol is adjusted accordingly.
• Surgery — the procedure typically takes 1 to 2 hours for an isolated MPFL reconstruction; longer when combined with TTO or cartilage repair
• Recovery room — you wake up in the recovery area; your knee is in a brace locked in extension. Physical therapy starts the same day or the next morning with crutch training and basic motion within the safe limits of the brace
• Going home — you go home with crutches, the brace, ice, prescribed pain medication, and clear written instructions. A responsible adult must drive you home
• First 48 hours — ice, elevation, prescribed medications, gentle motion as instructed. The first week's focus is effusion control, quadriceps activation, and walking with weight in the brace

Cold-compression devices and quadriceps muscle stimulators (when prescribed) can help reduce swelling and support muscle reactivation in the first weeks. The block typically wears off over the first 12 to 24 hours, during which the leg is numb and weight-bearing requires the brace and crutches because the leg is not protecting itself normally. This is expected and is the trade-off for the lower pain levels in that first day.

Recovery and Return-to-Sport Timeline

MPFL reconstruction recovery is a structured, milestone-based progression. The dates below are general guidelines — your specific plan may differ if a TTO or cartilage repair is added. Always follow your care team's personalized instructions.

The two factors that most consistently slow MPFL recovery are inconsistent physical therapy attendance and rushing back to high-impact activity before clearance. Skipping rehab sessions delays the quadriceps strength gains that gate brace removal and progression. Returning to running, jumping, or pivoting before milestone clearance increases the risk of graft failure or re-dislocation. For the full week-by-week walk-through, see Dr. Strickland's how long does MPFL recovery really take.

Risks of MPFL Surgery

MPFL reconstruction is a well-established surgery with predictable outcomes for most well-selected patients, but no surgery is risk-free. The risks reviewed at consultation include:

• Recurrent instability or graft failure — the most clinically relevant long-term risk. Most often associated with unaddressed bony risk factors (patella alta, trochlear dysplasia, elevated TT-TG distance), non-anatomic tunnel placement, or returning to high-demand activity before milestones are met. Imaging-guided patient selection and an honest discussion of whether TTO needs to be added are the main mitigations
• Persistent stiffness or loss of motion — reduced by good prehabilitation, early focus on regaining motion, and structured PT
• Patellar fracture — rare with all-suture anchor fixation, more often associated with patellar bone tunnels. Dr. Strickland's preference for two all-suture suture anchors is partly aimed at minimizing this risk
• Articular cartilage damage from patellar fixation — minimized by all-suture anchors compared with larger metallic implants or full-thickness bone tunnels
• Anterior knee pain — can persist after surgery, particularly when there is concurrent patellofemoral cartilage damage that is not addressed
• Numbness around the incision — common in the early post-op weeks, often improves over months
• Infection — uncommon but a serious complication if it occurs
• Blood clot (DVT or pulmonary embolism) — risk is mitigated by early mobilization and individualized prophylaxis
• Graft-site morbidity — with hamstring autograft only. Mild hamstring weakness and an additional small incision at the donor site. Avoided when allograft is used
• Anesthesia-related risks — including nausea, sore throat, rare allergic reactions to anesthetics, transient nerve irritation from the regional block
• Incomplete return to prior level of sport — some patients do not return to their prior level even with a technically excellent reconstruction; psychological readiness, fitness changes during the recovery, and the underlying anatomy all contribute

Outcomes are generally good in well-selected patients, but results depend on individual anatomy, adherence to rehab, and overall health. Specific risks for your case depend on your imaging, prior surgeries, concurrent procedures (TTO, cartilage repair), and goals — these are reviewed at consultation.

Common Patient Concerns

The three concerns we hear most often before MPFL reconstruction, with honest answers:

Insurance and Cost

MPFL reconstruction is covered by all major commercial insurance plans, Medicare, and most self-funded and union plans when the diagnosis and indication for surgery meet medical-necessity criteria. The variables that drive your specific out-of-pocket cost are:

• Your plan's deductible and coinsurance — the structure of cost-sharing differs significantly between plans
• In-network vs. out-of-network status — for the surgeon, the facility (Hospital for Special Surgery or affiliated outpatient surgery center), and the anesthesia group
• The bundled vs. separate billing for the surgeon, facility, anesthesia, imaging, physical therapy, and any concurrent procedures (TTO, cartilage repair)
• Out-of-network benefits — if you have them and choose to use them; we are happy to provide the codes you need to verify your benefits in advance

Before surgery, our office verifies your benefits, obtains pre-authorization where required, and reviews the estimated out-of-pocket cost with you. If your plan doesn't cover a specific aspect, we discuss it openly before the operation, not after.

For benefits verification or to discuss self-pay arrangements, call us at (646) 960-7227 or contact the office.

When to Seek a Sub-Specialty Second Opinion

A sub-specialty second opinion is particularly worth seeking when:

• You have had more than one patellar dislocation and want a clear discussion of whether MPFL alone or MPFL + TTO is the right operation for your specific imaging
• You have a failed prior MPFL reconstruction — recurrent dislocation, persistent anterior knee pain, loss of motion, or no progress in PT despite a good rehab effort
• Your imaging shows significant patella alta, elevated TT-TG distance, or trochlear dysplasia and you want to know whether your prior surgery was the right operation or whether the bony alignment also needs to be addressed
• You had a first-time dislocation with a loose osteochondral fragment or focal cartilage damage on MRI — this is a more nuanced surgical decision than a routine first-time dislocation
• You are an adolescent or young adult athlete with chronic instability and want a sports-medicine perspective on graft choice, return-to-sport timing, and growth-plate considerations
• You have generalized ligamentous laxity or a connective tissue disorder (Ehlers-Danlos, Marfan, hypermobility spectrum) and want to discuss whether the standard reconstruction protocol applies to you

Access & Office Locations

Dr. Strickland sees MPFL patients at two offices, both of which work with patients traveling in from outside the immediate area:

• New York City (primary): Hospital for Special Surgery, East River Professional Building, 523 East 72nd Street, 2nd Floor, New York, NY 10021. On the Upper East Side, accessible from Manhattan, the outer boroughs, Long Island, Westchester, and northern New Jersey via the Queensboro and Triboro bridges and the FDR Drive. Phone: (646) 960-7227.
• Stamford, CT (satellite): Stamford Chelsea Piers, 1 Blachley Road, Stamford, CT 06902 — convenient for patients in Fairfield County, lower Connecticut, and Westchester.

Many patients travel to New York for sub-specialty patellofemoral care, particularly for revision MPFL reconstruction, combined MPFL+TTO planning, and concurrent cartilage repair. We coordinate consultation, imaging review, and surgery scheduling to minimize travel for out-of-state patients.

Frequently Asked Questions

Related Specialty Care

For the broader diagnostic and treatment framework for kneecap dislocation and chronic patellar instability, see patellar instability. For the bony realignment side — tibial tubercle osteotomy, high tibial osteotomy, and distal femoral osteotomy — see joint preservation and osteotomy. When the patellar or trochlear cartilage has been damaged from prior dislocations, see MACI cartilage repair for focal cartilage repair. When chronic patellofemoral cartilage wear is established, see patellar pain and patellar arthritis. When ACL injury has occurred alongside a patellar dislocation, see ACL tear surgery.

For Dr. Strickland's published research and editorial commentary on MPFL technique, see her editorial on two-point patellar fixation, her commentary on robotic-assisted vs. freehand MPFL, her discussion of follow-up duration in MPFL studies, and her work on machine learning to predict MPFL reconstruction outcomes. For the practical patient-facing recovery and preparation guides, see how to prepare for an MPFL reconstruction, how long does MPFL recovery really take, MPFL and TTO questions, and how to tell if your MPFL reconstruction failed.