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Birmingham mid head resection is an alternative procedure for those people who do not qualify for Hip Resurfacing. For example, people having serious femoral head deformity or inadequate bone quality, are not suitable for a BHR. Rather than opting for a total hip replacement, patients in this condition have another bone conserving alternative which is the Birmingham Mid Head Resection. Apart from conserving the bone of the patient, those who successfully undertook the BMHR surgery will return to an active lifestyle. Dr. Derek McMinn invented the BMHR.
During the BMHR operation, the upper portion of the femoral head is opened, and any region of diseased or necrotic bone is removed. Then a conical cavity is cut, and the stem is tapped into place. The stem is then fitted with a large diameter modular head. It matches the patients’ own anatomy closely. The same acetabular cup which is used for a BHR is used for fitting the femoral head component. Scientific tests have shown that the physiological loading of the native femur is replicated by the conical design of the stem, and this prevents stress shielding bone loss in the long term. The BMHR is developed after the success of the BHR. It gives the same advantages of the Hip Resurfacing. The advantages are natural movements without dislocation and you will be able to return to your active lifestyle.
The line of resection of the femoral head is through the middle portion of the femoral head. This ensures the removal of the poor quality bone from the top half of the femoral head, and the lower part of the femoral head is retained. The lower part of the femoral head contributes to load transfer from the stem. The effect of load bearing through this upper region of the femur prevents the stress shielding deterioration of the neck. This has been noticed in other neck preserving hip replacements. The benefit of this procedure is that it gives you the option of converting to a total hip replacement in the future if the need arises.
The design of BMHR started in the early 2002. It was based on sound anatomical and biomechanical considerations. BMHR makes use of the same socket and the same bearing as a BHR. The wear performance too is similar to BHR. The main problem with BMHR was whether the stem design can favor long lasting stability and robust fixation, and whether the implant bone load transmission will provide safe and effective loads to allow the bone to withstand it in the initial phase.
The load transmission worked well, this was proved by preclinical finite element analyses. Implantations started in patients after January 2003. The stem fixation was stable and there was no evidence of the proximal femoral stress shielding. If your doctor suggests this treatment for you, it is important that you gather more information about it. You can ask us or speak to previous patients who have undergone this surgery, and ask them the side effects if any.