Foot Amputations

Direct Answer to Your Question

• Current Surgical Therapy 14e defines it precisely: "A ray amputation is a more involved procedure resulting in removal of the entire phalanx. It is performed when the disease process is more proximal in the toe, with involvement of the web space or metatarsal head."
• Sabiston Textbook of Surgery adds: "A ray amputation may be used when there is a need to resect the MTP joint or the distal metatarsal bone has become involved with infection."

Levels of Foot Amputation (Distal to Proximal)

1. Digital (Toe) Amputation

• Great toe amputation is the least well-tolerated because the great toe provides propulsion during ambulation.
• The most tolerable digital amputation involves the 3rd digit.
• A "fishmouth" circular incision is used at the base of the toe; the phalanx is divided with bone shears or a power saw, and the cut end is smoothed with a rongeur.
• Interphalangeal joint disarticulation is avoided (avascular cartilage impairs healing).
• Postoperative care: non-weight-bearing or heel-only weight bearing in a rigid soled shoe.

2. Ray Amputation

• A racquet-shaped incision - circular component around the base of the digit, with a longitudinal limb extending proximally over the metatarsal.
• Metatarsal is transected proximal to the head at a healthy margin.
• Digital arteries and nerves are carefully identified during medial/lateral dissection around the metatarsal.
• Wound may be left open if gross infection is present.

• First ray amputation significantly affects gait stability (propulsion) - requires proper footwear and physical therapy.
• Fifth ray amputation: incision must be extended over the lateral border of the foot.
• If the 2nd ray is amputated, consider a Lapidus-type procedure to stabilize the foot.
• Removing multiple central rays may allow approximation of medial and lateral borders ("closing" the foot).

3. Transmetatarsal Amputation (TMA)

• Long plantar flap + short dorsal flap ("fish-mouth" design).
• Dorsal incision at mid-metatarsal shaft level; metatarsals are sectioned in a beveled fashion (dorsal-distal to plantar-proximal) approximately 5 mm proximal to the skin incision.
• All plantar skin proximal to the MTP joints must be preserved.
• Tendons are divided under tension to allow retraction; alternatively, flexor and extensor tendons may be sutured to each other (myoplasty).
• Plantar flap is rotated dorsally for closure.

4. Lisfranc Amputation (Tarsometatarsal Disarticulation)

• Disarticulation of 1st, 3rd, 4th, and 5th tarsometatarsal joints; the 2nd metatarsal is transected ~2 cm distal to the medial cuneiform (to preserve the proximal transverse arch and base of 2nd metatarsal).
• Long plantar flap used for coverage.
• Peroneus brevis insertion at the base of the 5th metatarsal is preserved to avoid equinovarus deformity.
• Tibialis anterior and peroneus longus insertions at the medial cuneiform are meticulously preserved (or reattached) to prevent contracture.
• Achilles tendon is released; plantar fascia is approximated to dorsal periosteum.
• Plaster cast applied with talus in slight dorsiflexion.

5. Chopart Amputation (Midtarsal / Transverse Tarsal Disarticulation)

• Begin with a posterior incision and tenectomy of the Achilles tendon (excise 2 cm) BEFORE the main procedure - this is essential to prevent progressive equinus deformity.
• "Fish-mouth" incision with longer plantar flap; medial and lateral incisions begin at the transverse tarsal joints.
• Anterior tibial and long extensor tendons are resected distally and prepared for transfer.
• One or more ankle dorsiflexors must be transferred (to balance the foot stump).
• Patient placed in slight dorsiflexion rigid dressing for 6 weeks.

• High risk of equinus deformity (loss of all dorsiflexor attachments + unopposed Achilles pull) - can prevent ambulation and cause stump breakdown.
• Limited weight-bearing surface leads to continued pressure ulceration.
• May require tibiotalocalcaneal arthrodesis for stabilization.

6. Syme's Amputation (Ankle Disarticulation)

• Preserves the heel fat pad (which serves as the end-bearing weight surface).
• Results in a longer residual limb than BKA - better rehabilitation potential.
• Compared with Chopart, provides a more stable end-bearing stump but greater limb shortening.

Summary Table

• Mulholland and Greenfield's Surgery 7e - Digital and Ray Amputations section
• Current Surgical Therapy 14e - Minor Amputations / Amputation Types
• Sabiston Textbook of Surgery - Toe and Ray Amputation, Lisfranc and Chopart sections
• Campbell's Operative Orthopaedics 15e - Midfoot Amputations, Techniques 17.6-17.8