Armstrong (1999) — Lengthening of the Achilles tendon in diabetic patients who are at high risk for ulceration of the foot

Lengthening of the Achilles Tendon in Diabetic Patients Who Are at High Risk for Ulceration of the Foot

·J Bone Joint Surg Am·1999·300 citations·Foot & Ankle

This 1999 prospective study from Armstrong et al. asks a focused biomechanical question: how much does percutaneous Achilles tendon lengthening (TAL) reduce peak plantar forefoot pressure in diabetic patients with prior neuropathic ulceration and clinical equinus deformity? Ten patients underwent gait analysis with a validated force-plate system immediately before and eight weeks after percutaneous TAL.

Study Snapshot

Design

Prospective cohort

Objective

Determine whether Achilles tendon lengthening reduces forefoot plantar pressure in diabetic patients

Outcome(s)

Peak plantar forefoot pressure reduction at 8 weeks postoperatively

Subjects

10 diabetic patients, high-risk for foot ulceration

Percutaneous Achilles tendon lengthening

Inclusion

Diabetic neuropathy
History of neuropathic plantar forefoot ulceration
Healed ulcer ≥1 month pre-op

Follow-up

8 weeks

Statistics

Repeated-measures designForce-plate computer analysis

Key Findings

Percutaneous TAL reduced mean peak forefoot plantar pressure by ~27% — from 86 ± 9.4 to 63 ± 13.2 N/cm² (p < 0.001)
Mean passive ankle dorsiflexion improved from 0° to 9° postoperatively (p < 0.001), directly confirming correction of the equinus deformity
All patients met University of Texas Category 3 (neuropathy + deformity + ulcer history), a risk tier carrying ~36× greater ulceration risk than non-neuropathic diabetics
The postoperative pressure of 63 N/cm² crosses below the 65 N/cm² threshold above which ulceration risk is ~6× higher, per prior literature. A clinically meaningful shift
This was the first published study to quantify the effect of TAL on dynamic plantar pressures in this population

Clinical Relevance

When you encounter a diabetic patient with peripheral neuropathy, forefoot ulcer history, and limited ankle dorsiflexion (equinus), percutaneous TAL should be on your surgical planning radar — this study established that correcting equinus reduces peak forefoot pressure below the threshold most strongly associated with ulceration.

Postoperatively, protect the repair with a weight-bearing below-knee cast for 6 weeks before transitioning to therapeutic footwear.

Core

Lengthening of the Achilles Tendon in Diabetic Patients Who Are at High Risk for Ulceration of the Foot

Armstrong, Harkless, et al.·J Bone Joint Surg Am·1999·300 citations·Foot & Ankle

Lengthening of the Achilles Tendon in Diabetic Patients Who Are at High Risk for Ulceration of the Foot

Study Snapshot

Key Findings

Clinical Relevance

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Lengthening of the Achilles Tendon in Diabetic Patients Who Are at High Risk for Ulceration of the Foot

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Key Findings

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Lengthening of the Achilles Tendon in Diabetic Patients Who Are at High Risk for Ulceration of the Foot

Study Snapshot

Key Findings

Clinical Relevance

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Lengthening of the Achilles Tendon in Diabetic Patients Who Are at High Risk for Ulceration of the Foot

Study Snapshot

Key Findings

Clinical Relevance

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