[Arthroscopic reduction of congenital hip dislocations in infants].

Objective: Open reduction of congenital hip dislocations currently remains the standard treatment for those hip joints which are irreducible by closed means. The open reduction of the dislocated hip joint represents a relatively invasive surgical method. Thus, the goal was to develop a minimally invasive and safe procedure with a lower complication rate as an alternative to open reduction. This work presents the arthroscopically guided reduction of dislocated hip joints, first described in 2009, as a standardized surgical technique.

Indications: Failed closed reduction for congenital hip dislocation.

Surgical Technique: Arthroscopic reduction of the dislocated femoral head using an arthroscopic two-portal technique, a high anterolateral and a medial subadductor portal. The arthroscope is inserted through the subadductor portal. The high anterolateral portal serves as working portal. Step-by-step identification and removal of obstacles to reduction such as the ligament of the femoral head, fat tissue, capsular constriction and psoas tendon. Reduction of the femoral head under arthroscopic control.

Postoperative Treatment: The hip joint is retained in a hip spica cast with the legs in human position.

Results: Arthroscopic hip reduction of 20 congenital hip dislocations: 13 girls and 3 boys with an average age at the time of operation of 5.8 months (3-9 months). All children had multiple, unsuccessful attempts of closed reduction by use of overhead traction, Pavlik harness or closed reduction and hip spica application. According to the Graf classification, there were 20 type IV hips. According to the radiological classification of Tönnis, there were 9 type 4, 7 type 3, and 4 type II grades. The obstacles to reduction were capsular constriction, hypertrophic ligament of the femoral head, and an extensively large pulvinar in the acetabulum. An inverted labrum was not seen in any of the cases. In contrast, in 2/3 of the cases, there was considerable retraction of the dorsal edge of the socket due to the ligament of the femoral head expanding right over it. In all cases, postreduction transinguinal ultrasound and MRI were used to check the femoral head position in the cast postoperatively. In all cases there was a deep reduction of the femoral head in the acetabulum. There were no intra- or postoperative complications such as bleeding, infections or nerve lesions. There were no cases of redislocation or decentering of the femoral head, which was also confirmed after an average follow-up of 15 months. The mean AC angle at follow-up was 24.5°. There was one coxa magna in the series and one avascular necrosis with a fragmented femoral head according to the Salter classification.