Repositioning of a dislocated hip

The upward displacement of the hip joint, a so-called high hip dislocation, can be pain-free for many years if a stable replacement socket (pseudo-acetabulum) forms in the iliac crest ("blade" of the pelvic bone). Affected patients often can have astonishingly good function at first, but the associated leg shortening, often 6-8 cm, is noticeable and can be disturbing. This is aggravated by the fact that there is usually also an inhibition of abduction, so that the leg, which is already shortened, has to be lifted so that walking is possible at all. This means that in addition to the anatomical shortening, there is also a functional shortening, both of which increase the bending movement of the spine. In these cases of high hip dislocation, especially when the hip becomes increasingly painful, it is not possible to implant an artificial hip joint in the typical fashion. The artificial hip joint would have no stable fixation option in this much too high, non-anatomical position in the pelvis, and thus an extremely poor long-term prognosis. Acute intraoperative distraction of the hip is also not a feasible alternative, as this inevitably leads to nerve damage. Continuous hip distraction is thus the only physiological therapeutic approach. However, in the past, distalization of the hip was only feasible with external fixators, which carry a considerable risk of infection - a complication which can completely destroy the function of an artificial hip joint.

At ZEM-Germany, a revolutionary idea was born to open up new perspectives for patients with a painful high hip dislocation, which has attracted a great deal of international attention. A patented pelvic support plate in combination with the proven FITBONE intramedullary distracting nail, makes it possible for the first time to slowly pull down the femur ("distalization") without an external fixator and thus create the possibility of implanting an artificial hip joint in an anatomically correct position. In the first surgical step, the new pelvic support plate is positioned above the future position of the cup of the artificial hip, and firmly screwed to the pelvic bone. A FITBONE distraction nail is implanted in the femur and connected to the pelvic support plate via a ball and socket joint. During this first surgical step, the final artificial prosthetic cup is already implanted in the correct position, at the same height as the opposite side. If necessary, a cup roof reinforcement can be performed from the resected femoral head. After 5 days, the patient leaves the clinic and immediately begins the process of pulling the leg down into its proper position. Following a set protocol, the leg is pushed 3 mm/day in the first week, 2 mm/day in the second week and then 1 mm/day afterward, so that the soft tissues and especially the sciatic nerve can adapt to the slow stretching. The plate advantage: If the nerve does not tolerate this stretching, the patient feels numbness and the distalisation can be slowed down. This virtually eliminates the potential for nerve damage. As soon as the femur has reached the anatomically correct position, after a short relaxation phase, the FITBONE distraction nail is removed during the second operation and a regular prosthesis stem is implanted, which can then articulate with the already implanted socket. In addition to the anatomically correct prosthesis position, another advantage results: the pre-existing leg shortening is usually completely compensated for! This new procedure is only available at ZEM-Germany so far and has led to impressive results to date.