How is an acute (<2‑week) midsubstance Achilles tendon rupture in an adult patient managed with open end‑to‑end repair using a non‑absorbable braided suture (e.g., FiberWire) in a Krackow or Bunnell configuration, including the postoperative protocol?

Open End-to-End Repair of Acute Achilles Tendon Rupture: Surgical Technique

Open repair using an extended incision with non-absorbable braided suture (e.g., FiberWire) in a Krackow or modified Giftbox-Krackow configuration is an established option for acute midsubstance Achilles tendon rupture, offering direct visualization and secure tendon approximation. 1

Preoperative Considerations

• Patient positioning: Prone position with the foot hanging off the end of the table, allowing gravity-assisted ankle plantarflexion 1
• Anesthesia: General or regional anesthesia with tourniquet control
• Timing: Acute ruptures (<2 weeks) are ideal; no evidence supports delaying surgery for presurgical immobilization 1

Surgical Technique: Step-by-Step

Incision and Exposure

• Make a posteromedial longitudinal incision 5-8 cm in length, centered over the palpable tendon gap, typically 2-6 cm proximal to the calcaneal insertion 2
• Position the incision slightly medial to avoid the sural nerve, which runs along the lateral border of the Achilles tendon
• Deepen the incision through subcutaneous tissue using sharp dissection, identifying and protecting the sural nerve laterally
• Incise the paratenon longitudinally to expose the ruptured tendon ends 1

Tendon Preparation

• Identify and mobilize both proximal and distal tendon stumps, removing any interposed hematoma or degenerative tissue
• Freshen the tendon ends minimally if significantly frayed, but preserve tendon length
• Assess tendon quality and ensure adequate tissue for suture purchase (typically 3-4 cm on each side)

Suture Configuration

For Krackow Technique:

• Use No. 2 non-absorbable braided suture (FiberWire or equivalent polyethylene terephthalate) 3, 2
• Begin the Krackow stitch by passing the suture through the tendon approximately 1 cm from the cut end
• Create a locking, crisscrossing pattern with 3-4 passes on each side of the tendon, advancing proximally 1-1.5 cm with each pass
• The suture should exit approximately 3-4 cm from the tendon end
• Repeat the identical pattern on the distal stump 2

For Modified Giftbox-Krackow Technique (Biomechanically Superior):

• This technique demonstrates significantly higher clinical load-to-failure (373 N vs 285 N for Bunnell) and less gap formation (0.13 mm vs 2.29 mm) 4
• Perform a standard Krackow stitch as described above on both proximal and distal stumps
• Add transverse locking loops across the repair site to create a "box" configuration
• This provides enhanced resistance to gap formation during early rehabilitation 4

Tendon Approximation

• Position the ankle in 10-20 degrees of plantarflexion to reduce tension on the repair
• Tie the sutures with the tendon ends in direct apposition, ensuring no gap at the repair site
• Verify adequate tension by passively dorsiflexing the ankle to neutral—the repair should remain intact without gapping
• Consider reinforcing the repair with running absorbable suture (e.g., 2-0 Vicryl) through the epitenon for additional security, though this is optional 2

Closure

• Close the paratenon with absorbable suture if possible, providing additional coverage of the repair
• Close subcutaneous tissue in layers with absorbable suture
• Close skin with non-absorbable suture or staples
• Apply sterile dressing and place the ankle in a posterior splint with the foot in 20 degrees of plantarflexion 1

Postoperative Protocol

Weeks 0-2: Protected Immobilization

• Maintain non-weight-bearing status for 2-3 weeks in a posterior splint or boot with the ankle in plantarflexion 1, 5
• Remove sutures at 2 weeks if wound healing is adequate

Weeks 2-4: Early Protected Weight-Bearing

• Transition to early protected weight-bearing (toe-touch to partial) in a controlled ankle motion (CAM) boot or cast with heel lifts maintaining plantarflexion 1
• Early weight-bearing (≤2 weeks postoperatively) allows quicker return to activities during the first 6 months without increasing rerupture risk, provided the patient is compliant with dorsiflexion restrictions 1
• Use a protective device that limits dorsiflexion beyond neutral to prevent repair compromise 1

Weeks 4-6: Progressive Mobilization

• Begin gentle range-of-motion exercises by 2-4 weeks, but avoid dorsiflexion beyond neutral for the first 4 weeks 1, 5
• Progress to full weight-bearing in the boot with gradual reduction of heel lifts 1, 5
• Initiate bilateral concentric heel raises after 6 weeks 5

Weeks 6-12: Strengthening Phase

• Continue protected weight-bearing with progressive removal of heel lifts
• Avoid stretching and eccentric exercises until after 12 weeks postoperatively 5
• Transition out of the boot by 8-12 weeks with 1/8-1/4 inch heel cushions in regular shoes 5

Months 3-6: Return to Activity

• Begin sport-specific training after 12 weeks once adequate strength is demonstrated
• Return to sports typically occurs at 24 weeks (6 months) on average, though this varies by patient and activity level 1, 5, 6
• Base return-to-sport decisions on functional testing, including heel raise repetitions and strength testing 5

Critical Pitfalls and Complications

Wound Complications

• Open repair carries a 6% risk of superficial wound infection and potential for wound dehiscence 1, 7
• Meticulous soft tissue handling and posteromedial incision placement reduce these risks
• Avoid excessive tension on skin closure in plantarflexion

Sural Nerve Injury

• Sural nerve injury occurs in approximately 1.4-2.8% of open repairs 1, 7
• The nerve runs along the lateral border of the Achilles; maintain awareness throughout dissection
• Percutaneous techniques have higher sural nerve injury rates (3.2-5.2%) due to blind passage 1, 8, 7

Rerupture

• Surgical treatment reduces rerupture rates to 2.3% compared to 3.9% with nonsurgical management 8
• Patient noncompliance with postoperative protocols is the primary modifiable risk factor 1
• Emphasize the importance of adhering to dorsiflexion restrictions and weight-bearing progression

Deep Vein Thrombosis

• DVT risk is approximately 1% across all surgical techniques 8
• Consider chemoprophylaxis in high-risk patients per institutional protocols

Suture Material Considerations

• Non-absorbable braided sutures (FiberWire) demonstrate superior biomechanical properties compared to absorbable alternatives in some configurations 4
• However, absorbable sutures (polyglactin) are non-inferior to non-absorbable sutures for Krackow repairs in clinical outcomes, with no difference in rerupture rates, strength, or patient-reported outcomes at 12 months 3
• FiberWire with Giftbox technique provides the highest clinical load-to-failure (361 N) compared to other suture/technique combinations 4
• Absorbable sutures may reduce foreign body reactions (2% reoperation rate for FiberWire reactions in one series) 2

Comparative Outcomes

• Open repair demonstrates a 14.4% overall complication rate, with major complications (reoperation, deep infection, rerupture) occurring in 3% of cases 7
• No significant difference exists in functional outcomes between open, limited open, and percutaneous techniques when comparing return to activities, pain, or patient satisfaction 1
• Open repair allows direct visualization, reducing the risk of inadequate tendon approximation but increases wound-related complications compared to minimally invasive approaches 1, 8