Rupture of the extensor apparatus of the knee in adults is infrequent and dominated by patellar fracture, which in our experience is six times as frequent as quadriceps or patellar tendon tear. Patellar fracture poses few diagnostic problems and treatment is now well codified. Tension-band osteosynthesis is generally used, involving two longitudinal K-wires and wire in a figure-of-eight pattern looped over the anterior patella; sometimes, for more complex fractures, cerclage wiring is added to the tension band. Non-union is rare and generally well tolerated. Quadriceps tendon tear mainly affects patients over 40 years of age, in a context of systemic disease. Diagnosis is easily suggested by inability to actively extend the knee, but is unfortunately still often overlooked in emergency. In most cases, early surgical management is needed to reinsert the tendon at the proximal pole of the patella by bone suture. For chronic lesions, it is often necessary to lengthen the quadriceps tendon by V-Y plasty or the Codivilla technique. Patellar tendon tear, on the other hand, typically occurs in patients under 40 years of age, often involved in sports. Diagnosis is again clinically straightforward, but again may be missed in emergency, especially in case of incomplete tear. Surgery is mandatory in all cases. The procedure depends on the type of lesion: either end-to-end suture or transosseous reinsertion. In most cases repair is protected by tendon augmentation. Old lesions often require tendon graft or a tendon-bone-tendon-bone graft taken from the opposite side.