Tibial tubercle fractures (TTFs) are uncommon injuries, comprising <3% of all proximal tibial fractures. These fractures occasionally occur in conjunction with a patellar tendon injury (PTI). We aimed to identify risk factors associated with combined TTF and PTI. A retrospective review was performed of patients presenting to a single, tertiary children's hospital with TTF between 2012 and 2023. Demographic data, operative details, radiographs, and injury patterns were analyzed. Radiographs were assessed for the epiphyseal union stage (EUS), Ogden classification, and fracture patterns. Multiple logistic regression models were used to assess the impact of body mass index, comminution, fracture fragment rotation, EUS, bilateral injury, and Ogden classification on injury type. We identified 262 fractures in 252 patients (mean age, 13.9 ± 1.31 years). Of the patients, 6% were female and 48% were Black. Of the 262 fractures, 228 (87%) were isolated TTFs and 34 (13%) were TTFs with PTI. Multivariable analysis demonstrated fragment rotation on lateral radiographs (p < 0.0001) and Ogden Type-I classification (p < 0.0001) to be the most predictive risk factors for a combined injury. Rotation was associated with a substantial increase in the odds of a combined injury, with an odds ratio of 22.1 (95% confidence interval [CI], 6.1 to 80.1). Ogden Type-I fracture was another significant risk factor, with an odds ratio of 10.2 (95% CI, 3.4 to 30.4). The Ogden classification and fragment rotation are the most useful features for distinguishing between isolated TTF and combined TTF with PTI. This is the first study to identify risk factors for TTF combined with PTI. Surgeons may use this information to aid in preoperative planning. Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.