Ligamentous Ankle Injuries in Relation to the Morphology of the Incisura Fibularis: A Systematic Review.

Importance: Ligamentous ankle lesions are among the most frequent sport injuries. One of the key intrinsic stabilizers of the ankle joint is the incisura fibularis (IF), as it interlocks the distal tibia and fibula. Despite an abundant amount of studies related to ligamentous ankle injuries, scant attention has been given to the specific role of the IF morphology.

Objective: We systematically reviewed all literature focused on the relation between ligamentous ankle lesions and IF morphology.

Evidence review: A systematic literature search was conducted on PubMed, Embase and Web of Science according to the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines and registered on the International prospective register of systematic reviews (PROSPERO) database (CRD42021282862). In general, search terms were related to ankle and syndesmosis trauma/instability in combination with morphology parameters of the incisura fibularis. Studies categorizable as original research (randomized controlled trial or observational) were included. Studies concerning degenerative ankle disease and cadavers were excluded.

Findings: Thirteen studies were confirmed eligible and consisted of a prospective cohort (n=1), retrospective comparative (n=10), and observational (n=2) study design. Several studies have found an increased number of ankle ligament injuries and a higher incidence of chronic ankle instability in association with a shallow IF depth. In addition, statistically significant differences in incisura height and angle were also noted: a shorter incisura and more obtuse angle were more present in patients with ankle ligament injuries.

Conclusion and relevance: The majority of studies found distinct characteristics of the IF morphology associated with ligamentous ankle lesions, potentially due to lower osseous resistance against tibiofibular displacement. However, not all studies could identify this association and presented a heterogeneous methodological quality. Therefore, further prospective studies are warranted to clarify the relation between the IF morphology and ligamentous ankle injuries.

Lever of evidence: Level III, systematic review.