Achilles Tendon Approaches

What it exposes. The Achilles tendon approaches give access to the whole tendon from the musculotendinous junction to the calcaneal insertion — for acute rupture repair, chronic rupture reconstruction, insertional tendinopathy debridement and reattachment, Haglund resection, and FHL transfer augmentation. The challenge is not the tendon itself (subcutaneous and easy to reach) but the hostile soft-tissue envelope: thin posterior ankle skin, a watershed blood supply, and a sural nerve that crosses the field. Three open approaches, plus percutaneous. The workhorse is the medial paramedian incision (1 to 2cm medial to the midline) — the safest option because the sural nerve lies lateral and out of the field, and the medial skin is better vascularised than the midline. The lateral paramedian incision is reserved for revision after a prior medial scar or concurrent lateral ankle pathology; the sural nerve crosses it at mid-calf, so identification is mandatory. The midline direct incision gives the best exposure but sits directly over the tendon with the worst wound-breakdown rate and is rarely used. Minimally invasive percutaneous repair (Achillon, Ma-Griffith, PARS) lowers deep infection and wound complications but roughly trebles the sural nerve injury rate because needle passage is blind, with no significant difference in re-rupture versus open repair (Yang 2017). Why the medial paramedian is preferred. Quantitative cadaveric anatomy shows the sural nerve crosses the lateral border of the Achilles about 11cm proximal to the tuber calcanei and lies close to midline distally (Citak 2007), so a medial incision keeps it lateral and safe. Medial skin is supplied by posterior tibial artery perforators, giving a lower wound-complication rate than a midline incision that sits directly over the tendon with minimal coverage. Position & landmarks. Prone (simplest, best access to posterior structures) or supine with a bump under the ipsilateral hip for 15 to 20 degrees of internal rotation and the knee flexed 30 degrees over a bolster. Place the ankle off the end of the table so the full ankle range of motion can be used to set repair tension. A high-thigh tourniquet obscures the gastrocnemius bellies and raises VTE risk, so most cases are done without a tourniquet or with an Esmarch exsanguination only. Palpate the tendon midline and the rupture gap, and mark the incision 1 to 2cm medial to it. Global context. Achilles rupture incidence has risen worldwide to roughly 18 to 40 per 100,000 person-years, with a strong male predominance and a peak at age 30 to 50. Operative series report re-rupture in about 5 to 6 percent and deep infection in about 2 percent (Pajala 2002). Modern AAOS and BOAST/BOA guidance emphasise shared decision-making and early functional rehabilitation; smoking cessation before elective or chronic repair is universal best practice, as smoking, diabetes and corticosteroids are the dominant drivers of wound breakdown and deep infection.

The medial paramedian approach is the workhorse for open Achilles repair. Work down through the layers along the tendon, keeping the sural nerve lateral and out of the field, open the paratenon to expose the rupture, perform a Krackow core repair, then close the paratenon meticulously to restore the gliding surface and the tendon's dominant blood supply.

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Choosing the incision — three open approaches compared

Structures at risk, by layer

Early complications (less than 6 weeks). Superficial infection (5 to 10 percent) is managed with an oral anti-staphylococcal antibiotic per local guidance, local wound care and monitoring. Deep infection (about 2 percent) needs IV antibiotics guided by culture, surgical debridement, negative-pressure therapy and possible flap cover, and is often functionally devastating (Pajala 2002). Wound necrosis usually occurs at the midpoint of the incision over the watershed zone. Venous thromboembolism is notable — Achilles rupture is the highest-VTE-risk lower-leg immobilisation injury (symptomatic VTE about 8.5 percent) — yet routine prophylaxis has not reduced symptomatic VTE across cast-immobilised patients, so prophylaxis is individualised and risk-stratified (Nemeth 2019). Sural nerve injury (5 to 15 percent) presents as lateral-foot numbness with dysesthesia in a minority; management is observation over 6 to 12 months, neuropathic agents (gabapentin or pregabalin) and desensitisation, with exploration only rarely for a persistent painful neuroma. Late complications (more than 6 weeks). Re-rupture (about 5 to 6 percent — Pajala 2002) presents as a sudden "pop" with a positive Thompson test; 80 percent occur within 6 months during rehabilitation and are managed by revision repair with augmentation (primary re-repair alone carries a 20 to 30 percent re-re-rupture rate). Ankle stiffness (20 to 30 percent, usually lost dorsiflexion from overlengthening or prolonged plantarflexion) is minimised by avoiding full equinus and starting early range-of-motion exercises. A residual calf-strength deficit of roughly 10 to 20 percent is common at 12 months (recovering to about 80 to 90 percent by 12 to 18 months), and correlates with tendon elongation (Pajala 2009). Chronic incision pain and sural dysesthesia affect 10 to 15 percent. Extensile options. Extend the incision proximally along the medial border to reach the musculotendinous junction for a V-Y advancement or gastrocnemius recession (gaining length for a 4 to 6cm chronic gap), or distally to the insertion for Haglund resection and insertional reattachment. For a chronic rupture with a gap greater than 6cm, augmentation is required: FHL transfer (preferred — vascularised, in-phase, low donor morbidity), a proximally based gastrocnemius turndown flap, or V-Y advancement. Synthetic or allograft augmentation is less favoured. Post-operative protocol. Phase 1 (weeks 0 to 2): posterior splint in 20 degrees of plantarflexion, non-weight-bearing, elevation for 48 hours, individualised VTE prophylaxis, suture check at 10 to 14 days. Phase 2 (weeks 2 to 6): transition to a CAM boot with progressive dorsiflexion and progressive weight-bearing (full by week 6), active plantarflexion and passive dorsiflexion to neutral (do not force past neutral). Phase 3 (weeks 6 to 12): wean to a shoe with a 1 to 2cm heel lift, progressive strengthening (bilateral then single-leg heel raises) and proprioception; no running or jumping before 12 to 16 weeks. Phase 4 (months 3 to 6): running progression and sport-specific training, with full return to sport at 6 to 9 months based on functional testing (calf strength, hop testing) rather than time alone.

• Achilles tendon repair — the principal operation done through this exposure (acute rupture, Krackow core repair plus epitendinous suture).
• Tendo-Achilles lengthening — percutaneous or open lengthening for equinus contracture.
• FHL transfer augmentation — for chronic ruptures with a large gap (greater than about 5 to 6cm), harvested through a medial midfoot incision near the navicular and woven into the proximal stump through a calcaneal tunnel.
• V-Y advancement and gastrocnemius turndown flap — for moderate-to-large chronic gaps where primary apposition is not possible.
• Insertional Achilles tendinopathy debridement and Haglund resection — with reattachment to the calcaneal tuberosity.
• Percutaneous repair (Achillon, Ma-Griffith, PARS) — for selected acute mid-substance ruptures where wound healing is the priority, accepting a higher sural nerve injury rate.