Hip pain, hip, hip replacement/implant

The pain is caused by joint degeneration whose state of progression can vary widely. The cause of degeneration is mechanical over-exertion due to a congenital, acquired or trauma-induced axial misalignment of the knee joint, eg when the patient is knock-kneed or bow-legged. In deformed knee joints the weight-bearing area is reduced so that the load pressure is increased by a factor of 4.

Persistant swelling of the joint, connective tissue disorders, chronic inflammations or infections weaken the joint’s cartilage. In this stage, the joint capsule, muscles and tendons begin to shorten. The patient gets tired faster and feels pain when exercising or walking.

The x-ray will show bone ridges, bone densification and, at a later stage, blot-like cysts.

Joint degeneration is a chronic process that can be slowed down, but not stopped. Conservative treatment options include remedial gymnastics, physical therapy, drugs and injections. If detected early, corrective surgery of misaligned joints is a promising therapy. In cases where a joint implant is the only viable option, the implants must be individually aligned and adjusted to optimally fit the patient’s physical needs. The joint implants must fit in size, shape and be appropriate to the patient’s level of physical activity.

Knee implant/replacement
The standard implant used for knees is the so-called bicondylar sledge prosthesis, a bone-sparing resurfacing implant. The worn out cartilage surfaces are removed and the thigh bone ends coated with metal. The cartilage of the tibial head is removed and replaced with a metal plate. Between the two, a gliding surface is inserted as a tibial inlay. A possibly existing axial misalignment of the leg (bow legs, knock-knees) must be corrected during surgery, because it will cause as much wear and tear on the implant as it did on the natural cartilage. If only one part of the knee joint is affected by degeneration and there is no axial misalignment, a unicondylar sledge prosthesis will be suitable.
Today, there are excellent modular implant systems suitable even for complicated surgical procedures. The individual elements of these “building block systems” can be used to build on one another, for example in the treatment of bone defects or to compensate for unstable ligaments. Bi-axial joint replacements are used to treat major defects or a lack of ligament tension.
The correct axial alignment of the implant can be ensured mechanically or by means of a computer-assisted high-precision navigation system (0.1 mm, or 0.1 degrees).
For patients coming from an Asian or Islamic background there are high-flex knee implants allowing them to hyperflex the knee up to 165 degrees (normal: 130) so that they can sit cross-legged or pray while kneeling.
For women there are specially shaped knee implants which have the same length but are smaller in diameter than those for men. The required size is determined before surgery by means of an x-ray.