Chronic patellar instability after a primary dislocation event is common, and reasons for recurrent dislocations are multifactorial . Risk factors include trochlear dysplasia, insufficiencies in the medial stabilizing retinacular structures, increased tibial tubercle-to-trochlear groove (TT- TG) distance, and patella. Trochlear dysplasia reportedly is present in 85% of patients with recurrent lateral patellar instability. A sulcus-deepening trochleoplasty is recommended for patients in whom nonsurgical treatment is unsuccessful and who have chronic lateral patellar instability caused by a dysplastic trochlear groove. Contraindications for a trochleoplasty include patients with open physes or diffuse patellofemoral osteoarthritis (Outerbridge grades III and IV).
We describe a 21-year-old patient with severe trochlear dysplasia and concomitant grade-IV trochlear chondromalacia who underwent an osteoarticular allograft transplantation surgery (OATS) of the trochlear groove. The patient was informed that data concerning the case would be submitted for publication, and she provided consent.