Joint preserving surgical care of hip disorders
The hip joint has amongst other things a two-fold function: The joint must transmit a significant load from the body to the lower limbs and allow significant mobility within the three planes of space.
Optimal load transmission and stability occurs through maximal coverage of the head of the femur by the acetabular cup. Optimal mobility of the joint occurs through a minimum of constraints or minimal coverage of the head of the femur.
We believe that a majority of articular dysfunction and pain about the hip joint results from a dysbalance or mismatch between morphological inheritance and function.
There are some surgical means which may safely correct such unfavorable conditions. These belong in the realm of so-called joint preserving surgery of the hip joint
There might be cases which demonstrate a morphological discrepancy or mismatch between the cup of the acetabulum, the head and the neck of the femur.
This mismatch might be congential (inherent) or acquired. The discrepancies may lead to early degeneration and pain. By means of an open surgical approach to the hip joint (surgical dislocation of the joint), the joint surfaces can be seen, and possible coxo-femoral impingement (mismatch between the joint surfaces within normal range of movement) can be evalutated.
Bony and soft tissue impingement are dealt with and adaptations made to optimize hip joint function (cheilectomy of the femoral head, re-shaping of the acetabular cup). This operation can be done without harming the soft tissues or jeopardizing the femur.
It is much less invasive than, for example, joint replacement of the hip and may avoid or at least significantly delay the need for more invasive surgical means.
The hip joint may undergo abnormal growth before and after birth. Its development is terminated between age 12 and 14. Abnormalities in development of the joint (“hip dysplasia”) are checked systematically after birth and treated by orthopaedic or surgical means.
The most important problem which might occur during this development is the loss of stability of the joint or impingement which is due to an abnormal “cup” or acetabulum.
The natural progress or spontaneous development of such a joint is that it is likely to degenerate prematurely, becoming painful and impairing function. To save the joint, avoid or at least postpone the need for artificial joint replacement, surgical techniques by means of bone cuts around the joint have been developed.
The orientation of the cup can thus be modified by cutting it out of the pelvic bone and rotating and displacing it for better stability and congruency of the joint. Prerequisites for optimal results are detailed pre-operative 3-D imaging and image simulation of the re-orientation of the joint.
One thus can define more precisely abduction/adduction dysplasia and its correction (R1), Extension/flexion dysplasia and its correction (R2) and anteversion/retroversion dysplasia and its correction (R3).
Following trauma, maldevelopment or other diseases, function of the hip joint may be impaired and becoming painful.
After meticulous assessment of the problem by radiographs and other imaging means, the orientation of the upper end of the femur can be modified by cutting the bone for rotation and displacement.
The joint may thus be loaded on a healthy part of the joint surface or in a mechanically optimal orientation and thus avoid painful function and degeneration.