Summary

Pediatric tibial spine fractures appear to have similar posterior tibial slope to pediatric ACL injuries on both radiographs and MRI compared to age/gender matched controls

Abstract

Background

Fractures of the tibial spine (TSF) occur as a result of an anterior cruciate ligament (ACL) avulsion fracture from the proximal tibia. Both TSF and ACL injuries are associated with concomitant intraarticular pathology seen on Magnetic Resonance Imaging (MRI) and intraoperatively. In addition, posterior tibial slope (PTS) has been identified as a potential risk factor for ACL injury.

Hypothesis/Purpose: The purpose of this study is to describe concomitant injuries seen on MRI and at time of surgery for TSF and ACL patients, and to characterize posterior tibial slope in patients who sustain these injuries. Our hypothesis is that posterior tibial slope is increased in patients with TSF and ACL injuries compared to matched controls.

Methods

Utilizing an institutional review board approved retrospective study, we identified patients under 18 years of age who underwent arthroscopic management of a TSF from December 31st 2008 to December 31st 2021. Exclusion criteria were patients with a concomitant lower extremity fracture or posterior cruciate ligament injuries, poor imaging quality, and incomplete medical records. TSF patients were compared to an age and gender matched cohort of patients who underwent surgery for a mid-substance ACL rupture, and a control group. We evaluated concomitant injuries based on radiology and operative reports and measured PTS on radiographs as well as medial (MTS) and lateral (LTS) posterior slope on MRI for all groups.

Results

85 TSF patients met inclusion criteria, of which 44 had an MRI. There were 41 patients in the ACL group and 44 in the control group. The average age was 11.8 years. Concomitant injuries were identified on MRI in 59.1% of TSF and 51.2% of ACL patients, and intraoperatively in 36.5% of TSF and 37% of ACL patients. The most common concomitant injury was lateral meniscus tears. There was significantly increased radiographic PTS and MTS in the TSF and ACL groups (Radiographs 8.9°+/-2.7° TSF vs 9.5°+/-3.3° ACL vs 6.6°+/-2.3° Control, MTS 5.4°+/-3.1° TSF vs 4.9°+/-2.7° ACL vs 3.7°+/-2.3° Control). There was no significant difference in LTS between TSF and Controls, but there was between ACL and Controls (LTS 4.1°+/-2.8° TSF vs 6.8°+/- 3.9°ACL vs 4.3°+/- 2.3° Control).

Conclusion

Posterior tibial slope is significantly increased in patients who sustain a TSF or ACL injury, suggesting that it may be a risk factor for injury. Concomitant intraarticular pathology can be seen in both TSF and ACL injured patients, care must be taken to evaluate for additional pathology when treating these injuries.