Effects of Perthes Disease The 4 main stages of Perthes disease include: Initial Necrosis - the initial stage of loss of blood supply to the femoral head causing the area to become inflamed, may last several months and cause the child to move in a 'limp'. Fragmentation - The body replaces the dead bone and replaces it with a softer bone. At this point the bone is weak and the head of the femur is fragile and prone to collapse or breakage, this period happens over a timescale of 1-2 years. Re-ossification - During this stage, new bone begins to develop over the shape of the head of the femur, this stage of the disease can take a number of years. Healed - At this stage, regrowth of the femoral head within the hip join is complete. Quality of the bone will depend on the extent of damage that took place during fragmentation phase. Children aged 4-8 are most commonly affected however it isn't uncommon to be diagnosed in children younger than 4 years old. Around 1 in 9,000 children are affected and the specific cause is unknown. Perthes' disease is more common in boys and most commonly affects the hip joint. Children are likely to suffer from pain around the area with decreased movement at the joint. Most typically, children will present with their legs twist outward. Long term effects will depend on the severity of the deformity of the hip joint, some children may present with stiffness for a number of years after the condition however most children are able to return to normal activity within a few years. Whilst some children may require occasional periods of rest other children may return back to normal function and have no further problem within the hip joint. To book an assessment or for more information please email office@manchesterneurophysio.co.uk call 0161 883 0066 . Next → Error_log