Patellar Instability in Football Players. In Football Traumatology. 2nd ed. (Book Chapter)

Patellar instability is characterized by an abnormal, most of the time, lateral movement of the patella in the trochlear groove of the femur. The incidence rate has not yet been reported in football players. However, football is one of the most common sports to induce patellar dislocations as it involves twisting movements and contacts between players or with the ground. Many factors such as age, exercise, sex, family history, previous dislocation, and bony and soft tissue parameters can impact the risk of a patellar dislocation. The clinical examination therefore starts with an anamnesis including the exact mechanism and the family history of patellar dislocation. The physical examination must include palpation of relevant patellofemoral soft tissues, as well as evaluation of mediolateral mobility, apprehension, and J sign tests. To obtain a detailed description of the pathology, X-ray and CT scans or MRI are essential. The risk for recurrent dislocations is closely related to the patient’s age and the patellofemoral morphology. Nonoperative treatment is usually preferred for a primary dislocation without major structural risk factors (malalignment, dysplasia) or structural damage (static subluxation of the patella, osteochondral fragments). Conversely, surgery is recommended for secondary and recurrent dislocations. The current rehabilitation strategies aim to regain full range of motion, to stabilize patellar tracking and to strengthen the quadriceps. Players are allowed to return to sport when these rehabilitation targets are achieved, usually within 3–6 months after injury/surgery. However, many of them cannot return to their preoperative level.