Tibial Tubercle Osteotomy With Matrix-Associated Autologous Chondrocyte Implantation and Lateral Retinacular...

Patellofemoral cartilage defects can be caused by patellar instability, maltracking, trauma, or osteochondritis dissecans. Although cartilage restoration techniques, such as matrix-associated autologous chondrocyte implantation (MACI), are well-established, reducing contact pressures and shear forces on the graft remains critical for improving outcomes. This video demonstrates the surgical technique of patellofemoral offloading through tibial tubercle osteotomy (TTO) and lateral retinacular lengthening (LRL), combined with MACI, to optimize biomechanical alignment and enhance clinical results.

This case presents a 34-year-old woman with anterior knee pain, effusions, and a history of patellar instability, which failed to resolve with conservative treatment. Imaging revealed patella alta, trochlear dysplasia, and a full-thickness cartilage defect of the lateral patellar facet, which was confirmed during diagnostic arthroscopy as a 1.5 × 1.5 cm lesion. Due to persistent clinical symptoms in the setting of structural abnormalities, the patient was indicated for TTO with MACI and LRL.

The extensor mechanism is exposed through a midline incision slightly lateral to the patella. The tibial tubercle is identified, and an anteromedial osteotomy is performed using a saw and osteotome. The angle of osteotomy determines the degree of anteriorization, medialization, and distalization. Next, the lateral retinaculum is dissected, cut 1 to 2 cm from the patellar attachment, and lifted from the underlying capsule. A lateral and partial medial arthrotomy is performed to expose the patella. The patellar chondral lesion is debrided, and the prepared MACI membrane is placed on the recipient site and secured with fibrin glue. The patella is reduced, and the tubercle is repositioned and fixed with 6.5-mm cancellous screws. The lateral retinaculum is reapproximated with appropriate length and tension.

Combining MACI with TTO improves clinical outcomes compared with isolated MACI, with high rates of return to activity. TTO significantly reduces patellofemoral contact pressure, protecting the graft, while LRL enhances patellofemoral biomechanics, reducing instability and preserving vastus lateralis integrity.

Cartilage restoration techniques, when combined with patellofemoral offloading, offer an effective strategy for addressing complex patellofemoral defects, especially in cases of malalignment and soft tissue imbalance.

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