Does Skeletal Maturity Predict the Pattern of Tibial Tubercle Avulsion Fracture?

BACKGROUND: Proximal tibial physeal development and closure is thought to relate to tibial tubercle avulsion fracture (TTAF) patterns. Prior work has yet to formally evaluate the relationship between skeletal maturity and fracture pattern.  Using 2 knee radiograph-derived skeletal maturity assessments [growth remaining percentage (GRP) and epiphyseal union stage], we examined their association with TTAF injury patterns using the Ogden and Pandya fracture classifications. We hypothesized that different TTAF injuries would occur during unique periods of skeletal development.

METHODS: Pediatric patients sustaining TTAFs treated at a single institution (2008-2022) were identified using diagnostic and procedural coding. Demographics and injury characteristics were collected. Radiographs were reviewed to assign epiphyseal union stage, Ogden and Pandya classifications and for measurements to calculate GRP. Univariate analyses examined the relationship between injury subgroups, patient demographics, and skeletal maturity assessments.

RESULTS: Inclusion criteria identified 173 patients with a mean age of 14.76 (SD: 1.78) and 2.95% (SD: 4.46%) of growth remaining. The majority of injuries were classified Ogden III/Pandya C. Most (54.9%) were the result of the axial loading mechanism. Ogden groups showed no significant differences across all patient characteristics studied including age and GRP. With the exception of Pandya A fractures, we did not identify a direct relationship between GRP, age, and Pandya groups. Epiphyseal union stage differed for Pandya A and D groups.

CONCLUSIONS: A predictable pattern in TTAF characteristics across skeletal (GRP), epiphyseal union, or chronologic age was not identified in this study. Distal apophyseal avulsions (Ogden I/II and Pandya A/D) occurred across a broad chronologic and skeletal age range. No differences were identified in epiphyseal or posterior extension (Ogden III/IV and Pandya B/C) injuries. Although differences in age and GRP were identified among Pandya As, this is thought to be due to the degree of skeletal immaturity that is a prerequisite for differentiation from Pandya Ds.

LEVEL OF EVIDENCE: Level III-retrospective cohort study.