Surgical Treatment of Tibial Tubercle Fractures in Osteogenesis Imperfecta: A Restrospective Case Series.

Background: Osteogenesis imperfecta (OI) is a rare bone fragility disorder involving type I collagen. Although fragility fractures are common, tibial tubercle apophyseal fracture reporting is limited. This study evaluates our series of tibial tubercle operative fractures in OI patients. Methods: Retrospective review of all operative tibial tubercle fractures from 2010 to 2022, at a level one pediatric trauma and osteogenesis imperfecta referral center identified four patients with concomitant OI. Demographic information, OI type, antecedent and subsequent fracture history, surgical treatment, and OI treatment method were collected. Comparison was made with non-OI operatively treated tibial tubercle patients (n = 183). Results: The mean OI tibial tubercle surgical patient was 11 years (range 9-14). The mean non-OI tibial tubercle surgical patient was 14.5 years (range 8.5-17.0). Two out of four OI patients were female (50%) and 94.5% were male in the non-OI group. Within the OI group, one patient was diagnosed with OI after their tibial tubercle fracture (15 months later). OI types included: type I (n = 3) and type IV (n = 1). Before the tibial tubercle fracture, no patients were on bisphosphonate therapy and three were on vitamin D supplementation. All OI patients underwent open reduction with cannulated screw fixation. In two out of four (50%) OI patients, suture anchors were used. In the non-OI group 13.7% of patients were treated with suture anchors. Three OI patients were treated with a brace, and one patient was casted post-operatively. Immediate weight bearing was allowed in three OI (75%) patients and in 52.5% of non-OI patients. All OI patients returned to baseline activities at 5.4 months (IQR, 4.4, 6.2) and in 4.4 months (IQR, 3.4, 6.4) in the non-OI group. Conclusions: Patients with OI and surgically treated tibial tubercle fractures were younger than those without OI. The OI group made up 2.1% of all tibial tubercle surgical fractures. Suture anchor augments were employed in 50% of the OI cases and in 13.7% in the non-OI group. All OI patients returned to their baseline function, which is comparable to the non-OI group. Key Concepts: (1)Traditional surgical fixation methods including suture anchors can be used in OI patients.(2)Post operative immediate weight bearing as tolerated in a locked extended knee brace can be successfully utilized in OI patients.(3)Recovery time to baseline function is comparable between OI patients and non-OI patients after tibial tubercle surgery. Level of Evidence: Level III.