Introduction:The Birmingham Mid Head Resection prosthesis is a recently
developed hip prosthesis for patients who are keen on having
metal on metal hip resurfacing but do not have enough bone
stock in their femoral head to accept a resurfacing implant.
The BMHR, by its resection level is suitable for these
patients thereby opening an avenue for these patients to
benefit from the resurfacing technology.
Asian regional center for hip resurfacing is the only center
in Asia where currently BMHR surgeries are being performed.
Dr. Vijay C. Bose of ARCH is one of the very few surgeons in
the world to perform this surgery.
Concept:
It was increasingly becoming obvious that some younger
active patients were not candidates for resurfacing due to
some technical issues. In these patients only a stemmed
component was possible by removing bone stalk. The new BMHR
–Birmingham Mid Head Resection device is the ideal
prosthesis for this patient group as it retains almost all
the advantages of resurfacing. It is feasible even in
patients who have large cysts or other structural
abnormalities of the proximal femur.
The BMHR Prosthesis:
The acetabular component of the Birmingham Mid Head
Resection prosthesis is the same as that of the BHR
prosthesis. The femoral side is constituted by two modular
components - a stout stem with a fusicone contour in the
proximal portion and anti – rotation splines at the distal
end . The special BMHR head goes over the taper adapter
present at the top.
Current IndicationsThe Birmingham Mid Head Resection Prosthesis( BMHR) is used
in the following clinical conditions -
- Avascular necrosis of the femoral head with
significant bone loss.
- Femoral neck deformity (Valgus neck, Femoral Head
Retroversion)
- When the cysts in the femoral neck are large, hip
resurfacing cannot be performed. The BMHR is the choice
of implant for such patients.
- This implant is suitable for abnormal pathologies
like Perthes and SUFE.
Benefits and comparison:
- The BMHR prosthesis does not violate the femoral
canal. Hence it can be revised to total hip replacement
if required at a later stage.
- Loading at the head and neck junction is similar to
BHR hence the benefits of BHR prosthesis also applies to
the BMHR.
- Recent finite element analysis studies have proven
that the load distribution in BHR is very similar to
that of BMHR.
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