Hip and Knee Weakness and Ankle Dorsiflexion Restriction in Individuals Following Lateral Patellar Dislocation: A Case-Control Study.

To explore the relationship between ankle dorsiflexion range of motion (ROM) and hip and knee muscle strength between patients with a history of patellar dislocation (PD) to healthy controls.Case-control study.Orthopedical specialty outpatient clinic at a tertiary hospital.Eighty-eight individuals were recruited; 44 individuals aged 16 years or older, of both sexes, with a history of at least one episode of atraumatic unilateral or bilateral PD requiring emergency care (14 men; 30 women; mean age 20 years) and 44 healthy (control) individuals (11 men; 33 women; mean age 21 years) matched for age, weight, and height to PD cases.Assessment of hip and knee strength and ankle dorsiflexion ROM.Ankle dorsiflexion ROM was assessed through the lunge test with a goniometer. Hip and knee muscle strength was evaluated through isometric hand-held dynamometry. Differences between healthy and control individuals were assessed using Student t Tests and Mann-Whitney U Test.Patellar dislocation individuals presented with a reduced ankle dorsiflexion ROM [mean difference (MD): 9 degrees; effect size (ES): 1.39; P < 0.001] and generalized hip and knee weakness (MD range: 4.74 kgf to 31.4 kgf; ES range: 0.52-2.35; P < 0.05) compared with healthy subjects.Individuals with a history of PD have reduced ankle dorsiflexion ROM and hip and knee muscle strength compared with healthy controls.