Background: Trismus-Pseudocamptodactyly Syndrome (TPS) is a rare autosomal syndrome characterised by the inability to open the mouth fully, pseudocamptodactyly, short stature and foot deformities. The maxillofacial feature entails hyperplasia of the coronoid processes which mechanically interfere with the zygomatic processes during mouth opening.
Case report: A 22-year- old girl affected by a severe form of TPS was followed from the age of three years. Bone reossification was observed after two coronoidotomies of both hyperplasic coronoid processes. After the decision to perform a coronoidectomy, the four-year follow-up showed a favourable outcome. Meanwhile the patient developed an anterior open bite which was treated with a fourth orthognathic surgery. The follow-up underscores how the correction of malformation leads to the generation of EMG activity of the masticatory muscles after many years of passiveness.