If your kneecap has dislocated — slipped sideways out of its groove — you know how sudden and alarming the experience can be. What many patients do not realize is that after a first dislocation, the ligament that holds the kneecap in place is almost always torn. Without addressing that tear, the risk of redislocation is high. MPFL reconstruction is the surgical procedure that restores this ligament and breaks that cycle.

What Is the MPFL and Why Does It Matter?

The medial patellofemoral ligament (MPFL) is a short, flat band of tissue running from the inner side of the kneecap to the inner side of the thigh bone, near the medial epicondyle. Its function is to act as a primary checkrein — preventing the kneecap from sliding too far outward when the knee is near full extension.

When the kneecap dislocates laterally, the MPFL is torn in virtually every case. Even when the kneecap reduces on its own, the ligament damage remains. Without reconstruction, the kneecap lacks its primary medial restraint and remains vulnerable to repeat dislocation — sometimes with surprisingly minor provocation: turning quickly, stepping off a curb, or landing from a small jump.

Who Needs MPFL Reconstruction?

Not every patellar dislocation requires surgery. After a first episode in a low-risk patient, conservative management — bracing and physiotherapy — is appropriate. Surgery becomes indicated when:

Indications for surgery

  • Recurrent lateral patellar dislocation (two or more episodes)
  • First dislocation with an associated osteochondral fracture
  • First dislocation with high-risk anatomy (elevated TT-TG distance, trochlear dysplasia)
  • Persistent instability or apprehension despite adequate conservative management
  • Active patients who cannot accept the risk of recurrence in sport or daily life

Isolated MPFL reconstruction is most appropriate when the tibial tubercle to trochlear groove (TT-TG) distance is under 20mm and trochlear morphology is normal or mildly dysplastic (Dejour type A). When significant trochlear dysplasia or an elevated TT-TG distance is present, additional procedures may be required alongside MPFL reconstruction.

The Surgical Technique We Use

Our preferred technique uses FiberTape (Arthrex) with knotless SwiveLock anchors — a synthetic MPFL reconstruction that avoids the need to harvest any tendon from the patient's own leg. Because no autograft is taken, there is no donor-site discomfort and recovery is accelerated compared to hamstring-based reconstruction.

Patient positioning and diagnostic arthroscopy

The patient is positioned supine with the knee at 90° flexion (figure-4 position). Examination under anesthesia is performed to assess patellar tracking and lateral retinacular tightness. Diagnostic arthroscopy is then performed to evaluate patellar tracking and any intra-articular lesions. Concomitant pathology is treated at this stage. If lateral retinacular tightness is confirmed, lateral retinacular release is performed through the anterolateral portal before proceeding to reconstruction.

Patellar fixation: two SwiveLock anchors

A 2–3 cm longitudinal incision is made along the medial border of the patella. The medial retinaculum (first layer) is incised, the VMO is identified, and the periosteum of the medial patellar edge is exposed. Two 3.5mm SwiveLock anchors are placed into blind tunnels on the medial edge of the patella. The fixation points are proximal to the quadrisect point and proximal to the midpoint of the medial patellar edge — recreating the anatomical distribution of the native MPFL footprint. The central portion of the FiberTape is secured with these two anchors.

Femoral fixation at Schöttle's point

A short second incision is made over the medial epicondyle, and a subcutaneous tunnel is created between the two incisions in the second (MPFL) layer. The femoral attachment point — Schöttle's point — is identified radiographically on a precise lateral fluoroscopic image as the point anterior to the intersection of the posterior femoral cortical line and the posterior margin of the medial femoral condyle, proximal to Blumensaat's line. An MPFL guide is used to insert a 2.4mm K-wire into this point under imaging confirmation.

The two free ends of FiberTape are tunneled extra-articularly (in the second layer) from patella to femur and temporarily fixed around the K-wire with a Kocher clamp. Isometry is checked through the full range of motion. Once the position is confirmed, the tape ends are passed through the eyelet of the 4.75mm knotless SwiveLock anchor. A temporal suture is placed on the FiberTape within the eyelet to prevent it from sliding during insertion. The K-wire is overdrilled to 25mm depth with a 4.0–4.5mm cannulated drill, and the anchor is inserted.

Fixation angle: The FiberTape is fixed at 60–90° of knee flexion with the patella centered in the trochlear groove. Biomechanical data shows that fixation at less than 60° significantly increases medial patellofemoral contact pressure in deep flexion. The tape should be intentionally slightly looser than the native MPFL — overtensioning is the primary cause of postoperative stiffness and anterior knee pain with this technique.

After fixation, arthroscopy is performed to confirm patellar tracking. If overtightening is detected, the femoral anchor is removed and the procedure is repeated. The periosteum of the patella is tightly closed with 2-0 VICRYL sutures over the FiberTape to promote biological integration, followed by retinacular closure and skin tape.

What the Evidence Shows

Based on articles retrieved from PubMed, a systematic review by Migliorini et al. (2021) pooled outcomes from 1,777 knees after isolated MPFL reconstruction. At a mean follow-up of 40.7 months, redislocation occurred in only 1.7% of patients, and persisting instability was reported in 3.2%. Patient-reported scores improved significantly across all measures — Kujala, Lysholm, and Tegner — and revision surgery was required in only 1.4% of cases. DOI: 10.1186/s13018-021-02383-9

A systematic review by Colasanti et al. (2023) focusing on allograft MPFL reconstruction reported a mean Kujala score of 91.8 at final follow-up, 81.5% return to sport, a complication rate of 1.4%, and a recurrence rate of just 2.7% — lower than the 7.8% reported for autograft in the same analysis.

Taken together, the evidence supports MPFL reconstruction as a reliable, durable procedure with high patient satisfaction and low recurrence when performed with anatomically correct technique.

Recovery and Return to Sport

Because SwiveLock anchor fixation provides secure mechanical fixation immediately, rehabilitation after this technique is substantially accelerated compared to autograft-based reconstruction.

Rehabilitation protocol

  • Day 1: Full weight-bearing with crutches from the first postoperative day
  • Day 1 onwards: Early range of motion and muscle control exercises — patellar setting and straight leg raising — started as soon as possible
  • Month 2: Jogging permitted once adequate strength and neuromuscular control are confirmed
  • Return to sport: When neuromuscular function has sufficiently recovered — assessed individually based on functional criteria, not calendar dates alone

The absence of a donor-site wound and the mechanical security of the anchor fixation allow patients to begin full weight-bearing and knee motion from the first postoperative day — a meaningful difference from tendon-based reconstruction, where the healing graft-tunnel interface typically requires a more cautious early phase.

Frequently Asked Questions

Can I manage without surgery after a second dislocation?

Conservative management is possible, but recurrence risk after a second episode is substantially higher than after the first — approaching 50% or more in active patients. For anyone who wants to return to sport or lead an active life, surgery provides far more reliable protection.

Will my knee feel normal after reconstruction?

The goal is to restore the anatomy that was present before the injury. Most patients describe their knee as feeling stable and natural — and many who had lived with recurrent instability are surprised by how much more confident they feel in everyday movement after recovery.

What if I also have trochlear dysplasia?

Trochlear dysplasia — a flattened or shallow groove — increases recurrence risk after isolated MPFL reconstruction. In patients with significant dysplasia, trochleoplasty (surgical reshaping of the groove) may be needed alongside MPFL reconstruction. This is assessed carefully on preoperative MRI and CT.

Is this covered by Japanese national health insurance?

Yes. MPFL reconstruction is covered under NHI. For foreign residents enrolled in the Japanese health insurance system, the standard 30% co-pay applies — the same as for any other patient.

Had a patellar dislocation?

First consultation is free — 30 minutes, in person or by video. I will review your imaging and explain your options in plain English.

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References

Ishibashi Y, Kimura Y, Sasaki E, et al. Medial Patellofemoral Ligament Reconstruction Using FiberTape and Knotless SwiveLock Anchors. Arthrosc Tech. 2020;9(8):e1197–e1202. DOI: 10.1016/j.eats.2020.04.020

Migliorini F, et al. Isolated medial patellofemoral ligament reconstruction for recurrent patellofemoral instability: analysis of outcomes and risk factors. J Orthop Surg Res. 2021;16(1):239. DOI: 10.1186/s13018-021-02383-9

Colasanti CA, et al. Outcomes Following Medial Patellofemoral Ligament Reconstruction with Allograft: A Systematic Review. Bull Hosp Jt Dis. 2023;81(4):279–284.