Type 4 Tibial Tuberosity Avulsion Fractures: Surgical Treatment Early Outcomes and a Presentation of the Distal Cortical Fixation.

Background

The most published surgical technique for fixating Type 4 (Salter-Harris II) tibial tubercle avulsion fractures is uni-cortical in nature, and stability is suboptimal. This study presents a technique modification that is consistent with AO principles, by which the screws are aimed distally to purchase the posterior cortex of the distal fragment. This technique is defined as a "Distal Cortical Fixation". This modification has not been studied to date and harbors potential advantages. We aimed to assess the safety and efficacy of surgical fixation techniques for the above-mentioned fractures and to describe the new modification.

Methods

A retrospective review was conducted at a level 1 children's hospital for surgically treated Salter-Harris II tibial tubercle fractures. Inclusion criteria were patients who sustained Salter-Harris II tibial tubercle avulsion fractures and were documented to reach one of two radiographic endpoints: union (regardless of alignment) or non-union that necessitated additional interventions. Medical records and radiographic studies were analyzed for fracture union and alignment. A comparative analysis was conducted to evaluate outcomes based on different fixation techniques that included Distal Cortical Fixation, a Proximal Screw Technique, and a crossed or multiple screws/pins construct.

Results

A total of 37 patients were included with a mean age of 14.8 ± 1.2 years, with 34/37 (91.9%) being male. The most common procedure was a 1 to 3 screw fixation with a Distal Cortical Fixation (n = 21 (56.75%)), followed by a Proximal Screw Technique (n = 8, 21.62%), and a crossed or multiple screws/pins construct (n = 8, 21.62%). There was no difference between the groups in medical history and demographic features. The mean follow-up duration was 35.17 ± 36.79 weeks. There were no non-unions, and only a minimal change in the sagittal and coronal alignment (0.4 ± 1.94 (p = 0.872) and 0.53 ± 3.51 (p = 0.296) degrees, respectively) was noted and was not associated with the surgical technique.

Conclusions

The surgical treatment of Salter-Harris II tibial tubercle avulsion fractures, including Distal Cortical Fixation, was presented and was found to provide satisfactory union rates on a short term follow up.