The medial patellofemoral ligament (MPFL) has been identified as the primary medial restraint for lateral patellar translation and contributes up to 60% of the medial restraining forces to the patella.¹,²

Several techniques of MPFL reconstruction have been described, with various graft options, tunnel placements, and fixation options, with or without concomitant procedures, and with favorable outcomes.³,⁴,⁵,⁶,⁷,⁸,⁹,¹⁰ However, there are very few reports on implant-free MPFL reconstruction using soft-tissue fixation.

One of the concerns with MPFL reconstruction in skeletally immature patients is the potential for iatrogenic injury to the distal femoral physis. The described method of MPFL reconstruction would avoid any tunnels or implants, thus making it a safer procedure in this subgroup of patients.

On the patellar side, the issues with the placement of patellar tunnels are the risk of patellar fracture or chondral injury in the presence of small-sized patella. The current technique would avoid patellar tunnels and help avoid these risks.

Several techniques of MPFL reconstruction using soft-tissue approach have been described in skeletally immature patients. A 3-in-1 procedure has been described where lateral retinacular release, vastus medialis advancement, and transfer of the medial third of the patellar tendon to the medial collateral ligament (MCL) are performed.¹¹,¹²

In 1921, Galeazzi¹³ described the technique of semitendinosus tenodesis using intact distal attachment of the semitendinosus tendon, detaching it from its proximal musculotendinous junction, and looping it around the patella through an oblique tunnel from distal-medial to proximal-lateral direction and suturing the tendon onto itself or on an anterior aspect of the patella. Baker et al¹⁴ reported their results of Galeazzi’s technique in 42 patients (53 knees). Two-thirds of the patients had open physes, and 81% had good to excellent results. Letts et al¹⁵ reported results of this technique in 26 knees and found 23 (88%) were asymptomatic at follow-up.

Deie et al¹⁶ described a modified technique that re-routed the semitendinosus tendon through a pulley in the MCL to achieve a pull in the direction of the MPFL instead of medial and distal pull, as in the previously described Galeazzi technique. They reported their results in four children (six knees) under 10 years of age with a 4-year follow-up. One patient (two knees) had a positive apprehension sign, but there were no redislocations. The concern with their technique is the possibility of splitting the fibers of the MCL, making the pulley less functional.

Brown and Ahmad¹⁷ described a physeal sparing technique for reconstruction of the MPFL and medial patellotibial ligament, using the semitendinosus tendon. The tendon was kept attached distally to its tibial attachment, placed in a 20-mm blind tunnel on the medial side of patella using a docking technique and then sutured to the femoral attachment site of MCL. Compared with other techniques that have been described in children, this technique requires much smaller incisions and avoids patellar drill holes using soft-tissue fixation.

Steensen et al¹⁸ and Noyes and Albright¹⁹ reported soft-tissue MPFL reconstruction without any bony
tunnels on the femoral side using quadriceps tendon autograft, which was kept attached at its patellar insertion.

The current technique has been described in the French literature by Chassaing and Tremoulet²⁰ and later in the English literature by Parikh.²¹

For revision MPFL reconstruction and in the presence of previous patellar tunnels/fractures or for a small patella, this technique provides alterative fixation options.

The technique does not use any implants and could be considered when there are limited resources or economic constraints.

The minimally invasive surgery would result in cosmetic incisions and decreased surgical morbidity and postoperative pain.

The patella has a three-layered arrangement of fibrous soft tissue on its anterior aspect. These structures, from superficial to deep, are the superficial fascial layer (transverse orientation of fibers), intermediate aponeurotic layer (oblique), and the densely adherent, thickest, rectus femoris fibers (longitudinal).²² During MPFL reconstruction, the orientation of the MPFL graft through a soft-tissue tunnel underneath these three layers would be perpendicular to the orientation of the deepest patellar fibers, providing for good fixation without the risk of splitting or stretching the fibers on the patella.

The medial aspect of the knee also has a three-layered structural arrangement.²³ During MPFL reconstruction, the graft is looped around the medial retinaculum just proximal and posterior to the medial epicondyle. The graft would lie between layer 2 (retinacular layer) and layer 3 (capsular layer). If the medial structures around the medial epicondylar area are significantly compromised, an alternate femoral attachment point should be chosen; this decision should be based on clinical, magnetic resonance imaging (MRI), and intraoperative assessment.

Soft-tissue fixation of MPFL graft, as described in this chapter, would be considered a dynamic form of MPFL reconstruction, when compared with bony fixation of the graft (using tunnels, anchors, or interference screw), which would be considered static or rigid fixation. Hybrid fixation would be a combination of soft-tissue fixation on one end (patellar or femoral) and bony fixation on the other end.

Ostermeier et al²⁴ evaluated changes in patellofemoral kinematics after static and dynamic MPFL reconstruction in cadaveric specimens. Though both techniques stabilized the patella during a laterally directed force, the dynamic reconstruction showed on alteration of patellar kinematics, whereas static reconstruction significantly medialized the patellar movement.

More recently, in a cadaveric biomechanical study, Rood et al²⁵ demonstrated three to five times higher patellofemoral pressures from 60° to 110° of flexion after static MPFL reconstruction. The pressures after dynamic MPFL reconstruction were similar to native MPFL.

Though static MPFL reconstruction techniques are used more commonly, increased patellofemoral pressures could lead to osteoarthritis in long run. Small errors in position of MPFL attachment, especially on the femoral side, could accentuate these pressures.²⁶ Dynamic reconstruction, on the other hand, may deform more easily, may be more forgiving, and may function more like native MPFL.

Table 28.1 shows the indications and contraindications for soft-tissue fixation in MPFL reconstruction.

Patients present with a history of recurrent lateral patellar dislocation or a single patellar dislocation with subsequent episodes of lateral subluxation and feelings of instability.

Indications for MPFL reconstruction following a first-time acute patellar dislocation are rare. One may consider this procedure in the setting of a history of a contralateral patellar dislocation that required surgical stabilization or in cases where an osteochondral fragment is to be repaired.

Assessment of demographic risk factors (age, skeletal maturity, and sex), mechanism of injury, and anatomic risk factors can help in prediction of recurrent patellar instability.

Physical examination prior to surgery should demonstrate patellar apprehension with lateral patellar translation near full knee extension. Apprehension generally resolves as the knee is flexed and the patella enters the trochlear groove, which provides osseous stability.

Tenderness and swelling around medial epicondyle may be present in acute cases with femoral-sided injuries. This should be noted because a “blowout” on the medial side would preclude soft-tissue fixation at the femoral attachment side.

Lower extremity rotational profile (eg, femoral anteversion or tibial torsion), knee angular deformities (eg, valgus or varus), and gait should be recorded.

Patients’ ligamentous laxity should be assessed by assessment of joint hypermobility. Generalized ligamentous laxity should be considered “high risk” because the reconstruction may stretch out over time. In such cases, bony fixation on the femoral side should be considered. An allograft or stiffer autograft (semitendinosus) should also be considered as an alternative to gracilis autograft that is routinely used.

Radiographic examination should include anteroposterior view, lateral view, and an axial view. The patency of the distal femoral and proximal tibial epiphysis should be noted. The patellar height and trochlear morphology are analyzed on the lateral view.

Full-length lower extremity radiographs are useful for assessment of limb alignment and should be obtained in all skeletally immature patients and in those adults in whom varus or valgus alignment is suspected on physical examination.

MRI is useful to further assess trochlear anatomy and allow for measurement of the tibial tubercle-trochlear groove distance.

MRI should be reviewed for assessment of the MPFL injury (especially at its femoral attachment), patellar cartilage surface, osteochondral lesions, and patellar position in knee extension.