Dorsal first metatarsocuneiform exostosis
• dorsal ‘humping’ of midfoot in those with pes cavus (especially if anterior cavus)
• proliferation of bone from dorsal hypermobility of first ray (due to ‘jamming’)
Prominence of base of first metatarsal and medial cuneiform
Discomfort and erythema from shoe pressure
May have parathesias, tingling, numbness (due to compression of medial dorsal cutaneous nerve)
On x-ray – dorsal prominence visible; may be plantar gap in metatarsocuneiform joint.
Type 1 Local dorsal exostosis
Type 2 Dorsal exostosis with osteoarthritis of joint
Type 3 Dorsal exostosis with angular deformity
Type 4 Exostosis extends across other metatarsocuneiform joints
Type 5 Pseudoexostosis of dorsal humping of anterior pes cavus
Initially – avoid footwear
Padding on underside of tongue to accommodate prominence
Surgical excision or arthrodesis of joint.