We evaluated the results of treating unstable developmental dislocation of the hip (DDH) using percutaneous pin fixation and hip spica cast (PPF+HSC).

The technique was used in 19 cases (17 patients) of unstable DDH (over the age of 12 months) as an alternative treatment to maintain the reduction within the safe zone without excessive abduction at the time of of hip spica cast application. In this study, unstable hips redislocated around 45° abduction after closed reduction, with narrow zone of safety.

14 out of 19 hips were treated successfully by this method (73.7%) without redislocation in the hip spica cast. The other five hips were treated by using surgical procedures, such as open reduction and capsulorrhaphy, after the failure of PPF+HSC.

We regard this method as an effective alternative treatment (avoiding redislocation and AVN) for the closed reduction of unstable DDH, before considering open reduction, in those aged between 6 and 18 months (age range for closed reduction).