Intramedullary femoral lengthening with an 'unstable' hip without prior stabilisation: preliminary results of a case series

Background: Leg length discrepancy due to proximal migration of the femur commonly presents with a short leg gait and symptoms of hip and low back pain. The most common causes are chronic hip dislocation due to developmental dysplasia or the late sequelae of neonatal hip sepsis. It is usually recommended that the hip is stabilised prior to performing limb lengthening, and various techniques have been described. Unfortunately, these methods are not without complications, such as anatomical distortion making future arthroplasty more complex. We recognised a subgroup of these patients in whom the hip appeared unstable on plain film radiography, but in whom there was no proximal migration on weight bearing.