O3226: Tibial Tubercle Osteotomy in the Adolescent Management of Patellofemoral Instability – a Multicenter Review of Radiographic Indications

Background: The Tibial Tubercle Osteotomy (TTO) is widely utilized in the surgical management of patellofemoral instability (PFI) for medialization and/or distalization of the extensor mechanism to improve patellofemoral tracking. Due to its technique, its use is limited to those at or approaching skeletal maturity, and as such, few large adolescent-only patient series exist. A Tibial Tubercle-Trochlear Groove (TT-TG) distance greater than 20mm is the traditional indication for TTO, but differential anatomic and environmental risk factors for recurrence among adolescents may drive alternative decision-making. The purpose of this study was to retrospectively review a large cohort of adolescent PFI patients treated with TTO at 2 large pediatric orthopedic surgery centers and examine actual use patient characteristics and early outcomes for this procedure.

Methods: A retrospective review of adolescent patients with PFI undergoing simultaneous or staged MPFLR and TTO was conducted at 2 large pediatric orthopedic centers. Demographics, continuous and categorical radiographic variables (TT-TG, CDI, Dejour Classification, Oswestry-Bristol Classification), and procedural details were recorded. Descriptive statistics were used to summarize study variables while univariate analysis via were used to compare traditional surgical indications.

Results: A total of 125 patients (74.8% female) with a mean age at surgery of 16.25 years were identified (Table 1). The median number of patellar dislocations prior to surgery TTO was 3. Anteromedialization (AM) was done in 75 patients while anteromedialization plus distalization (AMD) was done in 50 patients. MPFL reconstruction was performed concurrently in most patients (92%) with the remaining having their reconstruction staged. The mean preoperative TT-TG distance and CDI in our cohort of TTO patients was 18.66 mm and 1.33, respectively. TT-TG values showed no differences (p < 0.05) across Dejour and Oswestry-Bristol Classifications or among those with and without patella alta (CDI>1.3).

Conclusion: In this large, multicenter cohort of adolescents and young adults undergoing TTO, the mean preoperative TT-TG distance was observed to be less than traditional indications of 20mm. TT-TG distances were not significantly different between different trochlear dysplasia classifications or patellar heights implying a multidimensional decision-making process. Further work is needed to determine the patient characteristics and other radiographic factors contributing to surgeons utilizing a lower radiographic threshold for TTO in adolescents through comparison with patients treated with MPFL reconstruction alone.