title: Surgical management of a double-layered patella: a case report.
abstract: The double-layered patella (DLP) is a rare intra-articular disorder that in most cases is associated with multiple epiphyseal dysplasia (MED). The DLP usually consists of an anterior and a posterior layer with a cartilaginous interface between the two parts. In this article, we present a case of bilateral DLP of a 17-year-old female adolescent with MED, suffering clinical symptoms on her left knee. Upon clinical examination, a painful "snapping" of the patella at 30-40 degrees flexion of the left knee was evident and two osseous layers could be identified in standard radiographs. Arthroscopic examination revealed a transient cranial displacement of the posterior osteochondral layer at 30-40 degrees knee flexion that replaced beyond 40 degrees knee flexion with a visible jump. Surgical management in this case of DLP comprised open debridement of the soft tissue interface and fusion of the two osseous layers using double-threaded screws leading to an excellent outcome at 12 months follow-up.
authors.affiliation: Division of Sports Medicine and Arthroscopy, Orthopedic Clinic, König-Ludwig-Haus, University of Würzburg, Brettreichstr. 11, 97074, Würzburg, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Goebel
authors.forename: Andre F
authors.initials: AF
authors.lastname: Steinert
authors.forename: Thomas
authors.initials: T
authors.lastname: Barthel
mesh_terms: D000293:Adolescent; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology / Q000601:surgery*; D010009:Osteochondrodysplasias / Q000150:complications*; D010329:Patella / Q000002:abnormalities* / Q000601:surgery*; D016059:Range of Motion, Articular; D020127:Recovery of Function; D016896:Treatment Outcome