Background: This study describes the anatomy and incidence of the metatarsophalangeal (MTP) joint meniscus, a structure not mentioned before in literature.
Methods: An anatomical cadaver study on 102 feet was performed with special attention to the first MTP joint anatomy. These results were compared with the per-operative findings in a clinical prospective study on 100 consecutive hallux valgus surgeries.
Results: On cadavers this meniscus is more common in patients with hallux valgus. Clinically, in patients with a mild hallux valgus the meniscus is found in more than half of cases during surgery, while it is seldom found in patients with moderate or severe deformities.
Conclusions: The presence of this structure seems to stabilize the MTP joint preventing progression of the hallux valgus deformity and may explain the pain, which is often seen in mild bunions in younger, patients. Once the rotational deformity increases the meniscus tears and slips into the joint. In the more advanced hallux valgus deformity this meniscus plays little function and seems to disappear, leading to arthrosis.