summary Congenital Dislocation of the Knee is a congenital knee condition that is primarily seen in patients with myelomingocele, arthrogryposis, or Larsen's syndrome. Diagnosis is made clinically with a hyperextended knee at birth. Treatment is a trial of reduction with manual manipulation and casting until the age of 3 months. Surgical management is indicated in cases of failure to gain 30° of flexion after 3 months of casting. Etiology Spectrum of disease including positional contractures rigid dislocation Structural components include quadricep tendon contracture anterior subluxation of hamstring tendon absent suprapatellar pouch tight collateral ligament Often occurs in children with myelomeningocele arthrogryposis Larsen's syndrome Associated conditions developmental dysplasia of the hip 50% will have hip dysplasia affect one or both hips clubfoot metatarsus adductus Classification Tarek graded by passive range of flexion and radiologic appearance can guide treatment Tarek Classification Radiology Range of passive flexion Grade I Simple recurvatum > 90° Grade II Subluxation/dislocation 30° - 90° Grade III Dislocation < 30° Presentation Presents with hyperextened knee at birth Treatment Nonoperative treatment reduction with manual manipulation and casting indications Tarek GI, initial treatment for GII (up to 1 month of age) most cases can be treated nonoperatively if both knee and hip dislocated, then treat knee first can't get Pavlik harness on hip if knee dislocated technique long leg casting on weekly basis Operative treatment surgical soft tissue release indications failure to gain 30° of flexion after 3 months of casting Tarek GII (identified after 1 month of age), GIII, and in recurrent cases goal of surgery is to obtain 90° of flexion percutaneous quadriceps recession (PQR) quadriceps tendon lengthening (V-Y quadricepsplasty or Z lengthening) anterior joint capsule release hamstring tendon posterior transposition collateral ligaments mobilization postoperative cast in 45 to 60° flexion for 3 to 4 weeks