Synonyms in a broader sense
artificial hip joint, total hip joint endoprosthesis (HTEP or HTE), hip joint prosthesis, total hip endoprosthesis, BHR, McMinn, Birmingham Hip Resurfacing, cap prosthesis, hip cap prosthesis, short shaft prosthesis
Definition
A total hip joint endoprosthesis is an artificial hip joint. The artificial hip joint consists of the same parts as the human hip joint. During the prosthesis implantation, the socket of the pelvis is replaced by an “artificial” one. The neck of the femur and the femoral head is replaced by the prosthesis part of the femur (stem) with the “artificial head” sitting on it. With the McMinn prosthesis only a minimal removal is performed in the femoral region.
Another alternative prosthesis model is the McMinn prosthesis
Especially in young patients, a surface replacement with minimal bone loss, as a new development in orthopedics, seems to be optimal. The BHR (Birmingham Hip Resurfacing) system offers a solution. It is a procedure that has been tested for over 10 years and is intended to guarantee gentle treatment of the bone.
Following the example of “why pull a tooth if it can be crowned”, this was applied here to the hip: “why cut off the femoral head if it can be capped and thus preserved? This original method was adopted about 2 years ago (author: Prof. McMinn, Birmingham, England) by first clinics in Germany. Long-term studies of over 10 years (approx.
3,000 patients) are available. In the year 2000, approx. 6,500 cap implantations were performed worldwide.
The results have also been convincing in Germany to date and are scientifically monitored by the University Hospital Dresden. The cap system also offers natural mobility and fast rehabilitation by maintaining the anatomical conditions. The acetabular cup is placed in the pelvis in the “classic” way, the femoral head is decartilaged and the acetabulum is cemented on.
The actual femoral head thus remains in place. The advantages are that this prosthesis can be exchanged for a classic hip prosthesis in the event of a necessary replacement operation. But there are also disadvantages.
Known disadvantages are the increased risk of a femoral neck fracture postoperatively. According to the current study situation, one must assume that a femoral neck fracture occurs at a rate of 3%. This means that about every 30 patients have to be operated again, which is a lot for orthopedic conditions.
Therefore it must be clarified exactly before the operation whether the respective patient is suitable for a McMinn or cap prosthesis. Risk factors are a known osteoporosis, overweight, a valgus femoral neck, higher age, female sex and many more. Furthermore, there may be a noise of the sliding pairing in the initial phase.
Initially, elevated cobalt-chromium levels in the blood can be detected. Whether or what consequences result from this for the organism is currently not clear. This type of prosthesis is only implanted in a few selected orthopedic houses. A comprehensive information page about this prosthesis system is planned here shortly. Please also note our further topic, which is especially suitable for younger patients: Short shaft prosthesis
