Allograft Reconstruction Technique for Chronic Pectoralis Major Tears

Allograft reconstruction is indicated for chronic pectoralis major tears because such tears will have fibrotic changes, retraction, and stiffness that prevent primary repair^1-3. Various reconstruction techniques have been described, particularly in cases in which the myotendinous unit is degenerated. Autografts (such as hamstring tendons and bone-patellar tendon-bone grafts) and allografts (such as Achilles tendon, fascia lata, and dermal grafts) have both been utilized^4,5. In the present video article, we describe a technique utilizing a doubled Achilles tendon allograft, which provides sufficient width to replicate the native sternal head insertion. A 3-point fixation construct is utilized to enhance graft-to-muscle interface strength.

An anterior axillary approach is utilized for cosmesis and optimal access. A 7 to 8-cm incision is made just lateral to the axillary fold, retracting the clavicular head laterally without exposing the deltopectoral interval. The sternal head is identified via MRI guidance and intraoperative cues, including fibrous "guitar-string" adhesions. Dissection remains anterior to the clavipectoral fascia to avoid neurovascular structures. The retracted muscle, typically fibrotic and shortened, is tagged with 3 high-tensile, nonabsorbable sutures. The Achilles allograft is folded to create upper and lower leaflets. Three rows of Krackow locking sutures are placed in the upper leaflet and 2 sutures in the lower leaflet. With use of a bent Hohmann retractor, the clavicular head is retracted laterally. The anatomic insertion site-posterior to the clavicular head and lateral to the bicipital groove-is prepared with use of a burr. Importantly, no osseous trough is created, minimizing fracture risk. Three 4.5-mm drill holes are made vertically. The folded Achilles allograft is secured to the humerus with use of unicortical suture buttons and a tension-slide maneuver. Sutures are tied through the graft for secondary fixation, first securing the graft to the bone without also securing to the torn muscle under tension. Attention then turns to the muscle-to-graft connection. The arm is adducted to neutral and internally rotated. The tagged sternal head is drawn between the Achilles leaflets and temporarily clamped. Proper tension allows 60° of abduction; if not, the muscle is repositioned more medially. Fixation is completed at 3 points. (1) Heavy sutures from the lower leaflet are passed posterior-to-anterior through the pectoralis and tied. (2) The tagging sutures from the pectoralis major are passed through the Krackow rows in the upper leaflet and tied, using rip-stops to reinforce fixation. (3) The uncut sutures from the lower leaflet are passed through the upper leaflet, closing the "fish-mouth" configuration. Excess graft is trimmed, and the leaflets are secured with use of a running 2-0 Vicryl (Ethicon) suture.

Nonoperative treatment with use of physical therapy often results in persistent deformity and strength loss. Alternative grafts include dermal allograft, fascia lata, hamstring autograft, and bone-patellar tendon-bone autograft^6-9.

A doubled Achilles allograft offers 3 main advantages. This technique replicates the native sternal head width. Three-point fixation enhances graft-to-muscle fixation strength, thereby reducing the risk of failure at the graft-tendon interface. Importantly, fixation of the allograft to the humerus is performed first, providing a stable foundation without depending on achieving correct muscle tension or graft length.

A doubled Achilles allograft reliably restores the pectoralis major tendon unit, even in ultra-chronic cases (up to 20 years post-injury). Favorable outcomes have been reported for strength and function restoration. In a study by Zacchilli et al.¹⁰, 3 military patients who underwent reconstruction at an average of 22.2 months post-injury had excellent or good outcomes and returned to active duty within 6 months. Similarly, Javed et al.¹¹ reported on 19 patients who underwent reconstruction at a mean of 12.2 months post-injury, with 84% experiencing significant strength improvement at 3.8 years postoperatively.

Preoperative Hibiclens (Mölnlycke Health Care) and benzoyl peroxide reduce infection risk; a cyanoacrylate dressing postoperatively protects the incision.Utilize an anterior axillary incision for better cosmesis and access.Employ a flexible circular retractor to optimize exposure.A headlamp facilitates deep visualization.Perform blunt dissection to mobilize the muscle without injuring surrounding structures.Use color-coded Krackow sutures for organization.Drill lateral to the bicipital groove to align the graft properly.Position the arm adducted and internally rotated during fixation for optimal tensioning.Inadequate muscle mobilization leads to poor tensioning.Over-tensioning restricts motion; under-tensioning compromises function. Slightly tight tension is preferred to account for expected lengthening over time.Posterior dissection risks neurovascular injury.Poor suture button deployment can jeopardize fixation; utilize multiple buttons for redundancy.

MRI = magnetic resonance imaging.