Achilles Tendon Reconstruction (Chronic Rupture)

Why this approach — at MOS

Reconstructing a chronic Achilles rupture demands pre-operative planning that begins with a careful MRI review. I measure the gap on MRI in the prone position — the position the patient will be in during surgery — and estimate how much the proximal stump can be mobilized before reconstruction planning is finalized.

The FHL transfer is my preferred technique for gaps of 3–6 cm because it provides a living, vascularized tendon with good pull-out strength, and the FHL's moment arm is well-aligned with plantarflexion force. The great toe flexion loss after FHL harvest is minimal in practice — cross-connections with the FDL preserve substantial function, and most patients do not notice a functional deficit.

For patients with prior wound complications or thinner posterior skin — as can be seen in older patients referred from Germantown and other communities across Montgomery County — I plan the incision with extra care to minimize dead space and ensure layered closure over the tendon repair.

Post-operative protocol follows a strict non-weight-bearing phase longer than for acute repair, because the FHL transfer must integrate and the Achilles reconstruction must mature before load is applied.

Who is a candidate?

Indications

• Confirmed Achilles tendon rupture more than 6–8 weeks from injury date (chronic/neglected rupture)
• Positive Thompson test with weakness in ankle plantarflexion
• MRI demonstrating tendon gap, retraction, and scar interposition
• Failed non-operative management with functional impairment (inability to walk normally, climb stairs, or exercise)
• Prior Achilles repair that has re-ruptured with significant tendon defect

Contraindications

• Active wound infection or posterior ankle skin compromise
• Peripheral vascular disease insufficient for wound healing
• Non-ambulatory patients where functional restoration is not achievable
• Significant medical comorbidities making a longer general/regional anesthetic unsafe (must be optimized pre-operatively)

Conservative Treatment First

A truly chronic Achilles rupture does not recover meaningful push-off strength without surgery. However, not every patient with a missed rupture requires surgery. Older, sedentary patients who are satisfied with modified activity (walking with an orthotic heel lift, no running or climbing demands) can sometimes adapt without surgery. An equinus ankle-foot orthosis (AFO) can compensate for push-off weakness in walking.

Surgery is strongly recommended for active patients, those who need to use stairs regularly, and anyone whose goal is to return to recreational sport. The benefits of reconstruction outweigh the risks in healthy patients with functional goals that exceed what conservative management can achieve.

The procedure

What Is Achilles Tendon Reconstruction (Chronic Rupture)?

Achilles tendon reconstruction is surgery for a chronic or neglected Achilles rupture — one that is more than 6–8 weeks old. Because the tendon ends have retracted and scarred, they cannot simply be sutured together. Reconstruction uses a nearby tendon transfer (flexor hallucis longus) or an allograft to bridge the gap and restore push-off strength.

This is a fundamentally different procedure from acute Achilles repair. If you are within 6 weeks of your Achilles injury, please see the Achilles Tendon Repair page, which describes primary end-to-end suture repair — a shorter, simpler procedure. Chronic reconstruction is more complex, requires different technique selection based on gap length, and has a longer recovery.

A chronic Achilles rupture can occur for several reasons: the acute injury was missed (often initially mistaken for a severe ankle sprain), the patient declined surgery and non-operative treatment failed, or a prior surgical repair broke down. Over weeks to months without surgical correction, the tendon ends fill with scar tissue, shorten, and lose the ability to transmit calf muscle force. The patient is left with profound weakness in push-off and an inability to perform a single-leg heel raise.

The key variable in planning reconstruction is the gap length between the tendon ends after scar tissue is excised. Gaps up to 2–3 cm can sometimes be bridged with careful mobilization and primary suture. Gaps of 3–6 cm typically require flexor hallucis longus (FHL) tendon transfer. Larger gaps may require Achilles allograft augmentation in addition to FHL transfer.

What Happens During Achilles Tendon Reconstruction?

Surgery is performed at an ambulatory surgery center as an outpatient procedure under regional or general anesthesia.

Positioning: Prone (face down) with the operative foot hanging over the table edge. Tourniquet on the calf.

Posterior ankle incision: A longitudinal medial posterior incision is made, typically 10–15 cm in length, larger than for acute repair due to the need to expose the tendon gap and harvest the FHL tendon. The paratenon is carefully preserved where possible.

Scar excision and gap measurement: Scar tissue is debrided from between the tendon ends until healthy, bleeding tendon tissue is reached. The resulting gap is measured with the ankle in neutral. This determines reconstruction strategy.

FHL tendon harvest: The flexor hallucis longus tendon runs just anterior and medial to the Achilles in the deep posterior compartment. It is identified, traced distally, and harvested as far distal as accessible — typically at the level of the sustentaculum tali. A separate small incision at the plantar surface of the great toe allows harvest of additional FHL length when needed. The FHL has robust cross-connections with the FDL tendon that preserve great toe flexion function after harvest.

Tendon transfer: A bone tunnel is made in the posterior calcaneus. The FHL tendon is passed through or alongside the tunnel and secured with an interference screw with the ankle in plantarflexion, placing the transfer under appropriate tension. The scarred Achilles tendon ends are then sutured over the FHL transfer to add additional bulk and strength.

Allograft augmentation: For large gaps or when additional tissue is needed, a processed Achilles allograft (donor tendon) is sutured into the repair, either as an onlay or as a bridging graft between the tendon stumps.

Closure: The paratenon is closed; subcutaneous and skin layers are closed. A posterior splint holds the ankle in mild plantarflexion.

Recovery timeline

Frequently Asked Questions