Abstract
We report a surgical technique for arthroplasty of the deformed hip after poliomyelitis.
A fifty three year old man presented to our unit with a long-standing history of hip problems since contracting poliomyelitis at the age of two. Unusually, both of his hips were affected. He had been operated on twice for his right hip. This had left him with a deformed upper femur with significant shortening. The right hip was sub-luxed on presentation; this was due to a markedly dysplastic acetabulum.
The polio and subluxation meant his muscles were weak and stretched. Like other authors, we were keen to achieve a stable hip. The senior author felt that a fully constrained socket would carry the following disadvantages:
-
Reduced range of movement.
-
It would be difficult to fit a constrained socket into the small amount of pelvic bone available.
-
Constrained sockets are more likely to loosen.
An alternative approach, using a large diameter unconstrained metal on metal articulation, was employed; stability was achieved with the large head and the relatively small socket still preserved bone stock. The components chosen were a 52mm MMT, Birmingham acetabular resurfacing prosthetic, articulating with a 46mm chromium cobalt head. A fluted stem CAD CAM (computer aided design, computer aided manufacture) femoral prosthesis was used, as he needed to fully weight-bear from the outset, because of the weakness in his left leg.
He has a good, pain-free range of movement. This represents a novel solution for arthroplasty in hips surrounded by weakened musculature. It avoids dramatic limitation of movement whilst minimising the bone stock loss and risk of dislocation. The patient is delighted with the medium term results.
Theses abstracts were prepared by Mr Peter Kay. Correspondence should be address to him at The Hip Centre, Wrightington Hospital, Appley Bridge, Wigan, Lancashire WN6 9EP.
