Flat foot and Bunion Deformity

Background:

Foot is made up of 26 uniquely shaped bones that are held together by >100 ligaments and tendons to maintain two (medial longitudinal and transverse metatarsal) reversed suspension-bridge-like springy arches to absorb the tremendous shocks in performing the demanding daily and sports activities. If certain ligaments and tendons are incompetent for whatever reason, then the affected part of foot can collapse and cause function-related problem of foot, such as for flat-foot and bunion conditions.


Flat foot (pronation):

This is probably the most well-known and commonly seen condition of foot caused by incompetent ligaments and tendons that are no longer able to hold up bones to maintain the arch on the inner side of the foot.


Bunion (Hallux valgus) deformity:

This is another well-known foot condition caused by incompetent ligaments. Bunion is formed by the destabilized and displaced first metatarsal bone. Losing its ligament support first metatarsal can be displaced sideway by the stress of weight-bearing activities to form the bunion deformity.


Flat foot and Bunion deformities:

First metatarsal bone forms the distal segment of inner/medial arch of the foot. When it loses its ligament support, it gives way not only in sideway to form bunion deformity but also in upward direction to allows the medial longitudinal arch to collapse and precipitate/accentuate the flat foot condition.


Syndesmosis procedure and flat foot:

Syndesmosis procedure can restore to some extend and particularly stabilize the, static and dynamic, longitudinal and transverse arches of foot by being able to re-align and truly re-stabilize particularly the main culprit, destabilized and displaced first metatarsal bone. Syndesmosis procedure restores the arches statically by restoring the plantar-ward orientation of first metatarsal through the metatarsocuneiform joint configuration when its metatarsus primus varus deformity can be corrected in its entirety without osteotomies. These arches can also be further accentuated dynamically by restoring the windlass mechanism of first ray. These improved arches can be statically assessed by x-ray and photo images (Fig. 1a,b) and also dynamically by plantar pressure scanning of the foot in walking (Fig. 2a,b). Clinically, patients would feel the medial arch and inner side of foot much firmer and stronger for standing and walking. Objectively, the transverse arch is restored by evidence of disappearance or much reduction of preoperative metatarsal calluses.


Osteotomy procedures and flat foot:

While syndesmosis procedure has been shown capable of re-stabilizing first metatarsal to reduce flatness of the medial arch of foot, statically through the metatarsocuneiform joint and also dynamically through the restored windlass effect in walking. However, bone-breaking bunion surgeries would decouple this natural anatomical relationship and surgeons have to instead manipulate the disconnected distal bone fragment to rebuild the arch in a rather tricky if not almost impossible way. Should break-n-shift of the normal first metatarsal bone fail to heal in its pre-calculated position then neither medial and transverse arches nor foot function can be restored, and even postoperative transfer metatarsalgia complication may

Reference information: http://www.bunioncenter.com/bunion/flat-foot.html
It is not intended as medical advice to any specific person. If you have any need for personal advice or have any questions regarding your health, please consult your Orthopedist for diagnosis and treatment.