A
saddle bone deformity, also known as a metatarsal cuneiform exostosis, is a
build up of bone that forms on the top of the arch. A
saddle bone deformity occurs as a result of hypermobility in the 1st metatarsal
cuneiform joint. Bone is deposited at the periphery of the metatarsal
cuneiform joint in an attempt to limit hypermobility. Therefore, what we
call a saddle bone is actually a problem that involves the entire metatarsal
cuneiform joint.
Saddle bone deformities are not usually painful in and of themselves.
The primary problem with a saddle bone deformity is trying to find shoes that
will accommodate the bump on the top of the foot. Also, saddle bone deformities tend to develop immediately beneath
the deep peroneal nerve. Painful nerve compression of the deep peroneal
nerve can result when pressure is applied to the nerve and underlying saddle
bone deformity by the tongue of a shoe.
Treatment of Saddle Bone Deformities
Conservative treatment of a saddle bone deformity includes avoidance of
direct pressure to the bump (exostosis). Open shoes, such as flip-flops or
low cut dress shoes can help to limit direct pressure to the
saddle
bone deformity. Padding can be used to protect the saddle bone from
compression by the shoe. The images at left show how to use a
tongue pad to create a small pocket on
the underside (tongue) of the shoe. This pocket places pressure to the
medial and lateral sides of the saddle bone.
Surgical
correction of a saddle bone deformity requires resection of the dorsal
exostosis. By removing
the exostosis, compression of the deep peroneal
nerve is relieved and patients can return to enclosed shoes. Resection of
a saddle bone is a procedure that takes approximately an hour to complete.
This procedure can be performed in a hospital or surgery center using general
anesthetic or local anesthesia and sedation. Patients are able to bear
weight on the foot immediately following surgery. Return to normal
activities take approximately 4-6 weeks.
