Prevalence and Characteristics Of The Fifth Toe Synostosis
Description
Background: Fifth toe synostoses are often an incidental finding on radiographic review of a patient. While the incidence and implications of synostoses have been described in anatomical studies of the hand, there is only one such report on the incidence of digital synostoses in the foot with a small subject pool.
Methods: Radiographic images are being reviewed from 1,000 patients of the Des Moines University Foot & Ankle Clinic who received a radiograph for any reason. Observation of digital synostoses will be recorded in all patients with exclusion of those who underwent an amputation or have non-weightbearing radiographs. Two podiatric medical students are recording average measurements which were obtained separately. Thus, each observer is blinded to each other. Other relevant reportables include a diagnosis of diabetes mellitus, hallux valgus, hammertoes and neuromuscular disorders as well as patient age.
Results: Interim results indicate the incidence of synostoses in the fifth toe to be 42% and the fourth toe to be 2% of the 300 patients that have been evaluated.
Discussion: The incidence of fifth digit synostoses has shown to be significant in the preliminary stages of this study. Multiple patients in this study had an additional synostosis in either the third or fourth digit. These preliminary results indicate a lower prevalence in comparison to the previous study on synostoses in the feet but a comparable prevalence in comparison to studies of synostoses in the hands. The researchers hope to expand this investigation to correlate the presence of a synostosis with other clinical abnormalities such as gait abnormalities and related functional impacts.
Citation Information
Fahy, Jillian; Smith, Ashlyn; and Johnstone, Mathew, "Prevalence and Characteristics Of The Fifth Toe Synostosis" (2026). Office of Research DMU Research Symposium. 27.
https://digitalcommons.dmu.edu/researchsymposium/2025rs/2025abstracts/27
Prevalence and Characteristics Of The Fifth Toe Synostosis
Background: Fifth toe synostoses are often an incidental finding on radiographic review of a patient. While the incidence and implications of synostoses have been described in anatomical studies of the hand, there is only one such report on the incidence of digital synostoses in the foot with a small subject pool.
Methods: Radiographic images are being reviewed from 1,000 patients of the Des Moines University Foot & Ankle Clinic who received a radiograph for any reason. Observation of digital synostoses will be recorded in all patients with exclusion of those who underwent an amputation or have non-weightbearing radiographs. Two podiatric medical students are recording average measurements which were obtained separately. Thus, each observer is blinded to each other. Other relevant reportables include a diagnosis of diabetes mellitus, hallux valgus, hammertoes and neuromuscular disorders as well as patient age.
Results: Interim results indicate the incidence of synostoses in the fifth toe to be 42% and the fourth toe to be 2% of the 300 patients that have been evaluated.
Discussion: The incidence of fifth digit synostoses has shown to be significant in the preliminary stages of this study. Multiple patients in this study had an additional synostosis in either the third or fourth digit. These preliminary results indicate a lower prevalence in comparison to the previous study on synostoses in the feet but a comparable prevalence in comparison to studies of synostoses in the hands. The researchers hope to expand this investigation to correlate the presence of a synostosis with other clinical abnormalities such as gait abnormalities and related functional impacts.
