Expanding the Role of Tibial Tuberosity Osteotomy with Distalization and Medialization: Long- Term Success in Patellofemoral Instability Without Redislocations with a mean follow-up of 8.6 years – A Retrospective Case Series Study

Background Patellofemoral instability is a multifactorial condition influenced by anatomical abnormalities and soft tissue dysfunction. Distalization of the tibial tuberosity is classically reserved for patients with patella alta, typically defined by a Caton–Deschamps (CD) index > 1.2. However, clinical experience suggests that certain patients with lower CD indices but distally deepening trochlear morphology may also benefit. This study is aimed to evaluate the long-term outcomes of tibial tuberosity osteotomy with distalization and medialization (TTO-DM) in patients with recurrent lateral patellar instability, regardless of patellar height. Materials and Methods This retrospective single-center study included 26 patients (17 females, 9 males) with recurrent patellar instability and Dejour type A, B, or C trochlear dysplasia. All demonstrated a distally deepened trochlear groove on MRI and underwent TTO-DM. Patients were followed for a minimum of 4 years (mean, 8.6 years). Outcome measures included the Kujala and Lysholm scores, radiographic assessment of the CD index and Kellgren–Lawrence grade, complications, range of motion, and pain during squatting. Results Kujala scores improved from 60.1 ± 18.7 to 93.8 ± 7.1 (p < 0.0001), and Lysholm scores increased from 59.5 ± 20.7 to 93.8 ± 7.9 (p < 0.0001). The mean CD index decreased from 1.2 to 0.88 postoperatively. No patellar redislocations or progression of patellofemoral osteoarthritis were observed. One superficial infection resolved with oral antibiotics, and one tibial tubercle fracture was successfully managed with plate fixation. Four patients had delayed recovery but returned to full function without long-term sequelae. Conclusion TTO-DM led to excellent functional outcomes and complete redislocation prevention, even in patients with CD indices ≤ 1.2. These findings suggest that surgical indications for distalization may be expanded based on trochlear morphology rather than CD index alone. Although limited by its retrospective design and small sample size, this study provides one of the longest follow-ups supporting this approach in patellofemoral instability management.