The treatment of patellar instability in skeletally immature patients can be challenging. Patients presenting at a young age often have more severe underlying malalignment (i.e., trochlear dysplasia) that typically leads to the development of symptoms prior to skeletal maturity. Although soft tissue procedures (medial patellofemoral ligament reconstruction or proximal realignment) may be appropriate in some patients, many patients with developmental patellar dislocations have significant bony abnormalities (i.e., lateralized tibial tubercle) that are not addressed with soft tissue procedures alone. Alternative procedures in these patients include nonanatomic reconstructions such as the Roux-Goldthwait procedure and Galeazzi procedure. In our experience, the results of these procedures have not been reliable. Given the lack of reliable treatment options in patients with underlying bony malalignment, skeletally immature patients are frequently counseled to wait until skeletal maturity for definitive treatment (tibial tubercle osteotomy). Particularly in the young child with significant growth remaining, worsening of trochlear dysplasia and patellar instability often occur and can result in abnormalities that are difficult (if not impossible) to correct at skeletal maturity.

Medial patellar tendon transfer with proximal realignment (Fig. 18.1) has been used at our institution for over 30 years in children with congenital or developmental patellar dislocations and significant underlying bony malalignment. Gordon and Schoenecker¹ initially described our institution’s early experience with this procedure. Transection of the patellar tendon with medial transfer and reattachment allows for near-anatomic reconstruction of underlying malalignment. In the child with significant growth remaining, restoring proper patellofemoral stability may contribute to favorable trochlear remodeling. For the surgeon without experience in this technique, transection of the patellar tendon is intimidating due to the potential concern for healing. In the extensive experience with this procedure at our institution, long leg cast immobilization postoperatively results in reliable healing without significant issues with arthrofibrosis in this population. In this chapter, we describe our surgical technique for medial patellar tendon transfer with proximal realignment.

Surgery is performed supine with a bump under the ipsilateral hip. A nonsterile tourniquet is placed prior to sterile prep of the surgical limb. Standard preoperative antibiotic prophylaxis is used. After exsanguination of the leg, the tourniquet is inflated. A midline incision from the level of the superior pole of the patella to 3 cm below the tibial tubercle is used (Fig. 18.2). Circumferential skin flaps are raised at the level of the retinaculum (Fig. 18.3). We have not routinely used arthroscopy in this young patient population, unless clinical evaluation
suggests underlying chondromalacia or loose body. We have found intra-articular pathology to be relatively uncommon in this patient population.