Introduction
If a child suffers from Perthes disease, priority must be given to relieving the affected leg and preventing deformation of the femoral head. If these therapeutic measures are carried out successfully during the resorption and rebuilding of the bone during the course of the disease, the prognosis is good. The child can thus recover without permanent damage.
The disease process itself cannot be influenced by any currently known therapy and usually takes 4 years. Since a complete relief of the hip joint is sometimes not possible or is initiated too late, deformities still occur again and again. These must usually be surgically corrected, otherwise movement restrictions and pain can occur.
The healing process is usually positively influenced by an operation. Physiotherapy is often used to support the healing process. This maintains and trains mobility – a prerequisite for any therapy.
Operation
If the joint head and the socket are optimally adapted to each other, this is called “containment”. The hip roof encloses the femoral head as completely as possible. If this is not the case, movement can be restricted.
When an operation is in question, attention is paid to the containment status of the joint on the one hand and the catterall group on the other. This grouping includes four different stages, which, however, do not correspond to the general disease stages. They describe, in ascending order from stage 1 to 4, the extent of the defect of the femoral head during Perthes disease.
An incomplete containment and the catterall groups 3 and 4 may be an indication for surgery. Normally, the following principle applies: very young or young patients with a low catterall group should initially be treated conservatively. The indication for surgery must be carefully considered by the treating physicians.
If mobility deteriorates during conservative treatment, surgical measures can be considered again. In varisation osteotomy, the patient is operated on the femur. A wedge is cut out of the bone with the pointed end pointing to the outer side of the leg.
This causes the femoral head to tilt towards the middle of the body (or body plumb line). An inclination of 10 to 15 degrees is aimed for. This change in position means that the femoral head lies better in the acetabulum again.
In addition to the actual treatment effect, a varisation osteotomy has another good thing to offer: in some cases, the destroyed femoral head regenerates more quickly after the operation. It is assumed that the surgical changes to the bone increase the healing stimulus and thus promote the growth of the bone substance. If the varisation osteotomy has not brought the desired success or if a decision is made against such an operation, a pelvic surgery according to Salter can be performed.
The principle is similar here, but the other way round – a wedge is inserted instead of removing bone material. The ilium of the pelvic girdle is sawed off horizontally in the area of the acetabulum and a wedge is inserted between the resulting bone fragments. The hip roof is now more inclined downwards, i.e. generally flatter.
As a result, the femoral head lies more centrally in the joint. This also compensates for the shortening of the leg length, which either resulted from the varisation osteotomy or occurred due to Perthes disease. After the operation, intensive pain therapy must be carried out and immobilization must be ensured with the help of plaster casts and bed rest.
Salter’s surgery is associated with more complications than varisation osteotomy. These include, for example, disturbances in wound healing and damage to nerves or vessels. Physiotherapy should not be performed immediately after the surgery. The bone must first be spared and healed before the joint can be loaded again. After about 6 weeks, the use of physiotherapeutic treatment can be considered.
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