Subchondral Bone Degeneration and Pathology 3-15 Years Following Ankle Sprain Injury in Adolescent Sport.

BACKGROUND

Sport-related ankle sprains (SASs) are prevalent in adolescents (ages 10-19), increasing the risk of developing posttraumatic osteoarthritis (PTOA). Although early ankle osteoarthritis (OA) is not well defined, OA eventually includes alterations in bone mineral density (BMD), structural changes, and soft tissue pathology. This study examined the impact of SAS sustained in adolescent sport on bone and soft tissue structural outcomes 3-15 years postinjury.

METHODS

Participants (n = 10) with prior unilateral SAS in adolescent sport (HxAI) were compared to age- and sex-matched controls. To assess injury-related pathologies and BMD, 1.5-tesla (T) extremity magnetic resonance imaging (MRI) and computed tomography scans were used. Semiquantitative scores for injury patterns and OA features from MRI scans were summed and compared between groups. The talus, calcaneus, navicular, and 5% distal tibia were segmented, and BMD was measured for each bone.

RESULTS

All HxAI participants exhibited MRI injury pathology (median 2; IQR 1-6), whereas only 1 of 10 controls showed pathology (median 0; IQR 0-0), χ2(1, n = 20) = 16.36, P < .001. Both the injured and uninjured ankles in HxAI displayed injury pattern pathology. Additionally, 3 of 10 injured ankles and 2 of 10 uninjured ankles in the HxAI group (median 0; IQR 0-3), but none of the controls (median 0; IQR 0-0), exhibited OA features. In the HxAI group, talus BMD was lower in the injured ankle (502.4 ± 67.9 g/cm3) compared with the uninjured ankle (515.6 ± 70.1 g/cm3) (F = 13.33, P = .002), with no significant BMD differences at the calcaneus, navicular, or 5% distal tibia. No differences were observed between the ankles of the control group.

CONCLUSION

The presence of injury pattern pathology, structural changes, and reduced talus BMD suggest that degenerative changes may occur in individuals as early as 3-15 years following ankle injury.