Split Pectoralis Major Tendon Transfer With Achilles Allograft for Chronic Medial Scapular Winging

Abstract

Background:

Split pectoralis major tendon (PMT) transfer is effective at treating persistent medial scapular winging refractory to conservative management.

Indications:

The primary indication for a PMT transfer is scapular winging secondary to serratus anterior palsy caused by long thoracic nerve injury. In this case, the patient is a 22-year-old male with years of symptoms that interfere with his activities of daily living and ability to play recreational basketball.

Technique Description:

The patient was placed in a semi-supine position. The deltopectoral interval was identified and dissected. The sternal head of the pectoralis major was isolated and tagged, and a tenotomy was then performed. An Achilles allograft was prepared in a sterile fashion and secured to the pectoralis tendon using multiple heavy nonabsorbable sutures. A scapular incision was made to identify the inferior angle of the scapula. A bone tunnel was created, and the allograft was shuttled through the aperture and tensioned into place.

Results:

Split PMT transfer is associated with improved pain scores and functional outcomes, while offering a lower complication rate than other surgical techniques. Patient satisfaction is high; 80% of patients would recommend the surgery. The patient in this case is now 16 weeks post-surgery and reports 0 out of 10 pain.

Discussion/Conclusion:

This technique study demonstrates that split PMT transfer with Achilles allograft augmentation is a viable treatment option for patients with persistent scapular winging.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

This video demonstrates our technique for a split pectoralis major tendon (PMT) transfer with an Achilles allograft performed for chronic medial scapular winging. Here are our disclosures. This is an overview of our presentation.

Background

First described in 1904, pectoralis major transfer is indicated in the setting of medial scapular winging, most often secondary to serratus anterior palsy caused by long thoracic nerve injury.^1,10 Surgery is typically reserved for after 2 years of nonsurgical management with limited functional improvement. ⁸ Debate exists regarding the best surgical approach for treating this condition. Techniques may involve split or complete transfers of the PMT, with the former preferred over harvesting both clavicular and sternal heads such as in complete tendon transfers.^2,3 Some surgeons prefer an indirect approach using an autograft or allograft to prolong the PMT, while others favor direct sternal head transfer without tendon prolongation. ⁴ A 2014 study published by Chalmers et al ¹ reported an even split between direct and indirect transfers.

Case Presentation

Here is our case presentation. A 22-year-old left hand–dominant male presented to our clinic with a chief complaint of right scapular winging and shoulder pain. He said that the symptoms had been present intermittently for years and that he could not remember his shoulder ever feeling normal. He denied any precipitating injury or trauma to the shoulder. He had previously been seen by neurology, during which electromyography nerve conduction testing revealed absent long thoracic nerve function. Outside orthopaedic evaluation had recommended scapulothoracic fusion.

Preoperative planning included physical examination in the office. An evaluation of scapular mechanics during simulated push-off testing demonstrated hyperlaxity with forward flexion and abnormal scapulothoracic mechanics with significant medial scapular winging on the right side. Specifically, the inferomedial border of the scapula is seen excessively elevating and protruding posteromedially, worsened with forward arm flexion of the ipsilateral extremity. The contralateral scapula also demonstrated mild winging; however, this was not bothersome to the patient. Therefore, we elected to only treat the right shoulder. He had full active and passive range of motion with normal rotator cuff strength. Drop arm testing was negative. Radiographic imaging demonstrated normal joint spaces and no fractures or traumatic malalignment.

Repeat physical examination in the preoperative holding area again demonstrated significantly abnormal scapular mechanics with medial scapular winging. For this procedure, the patient was placed in a semi-supine position, allowing for both an anterior-based incision for PMT harvest and a posterior-based incision for tendon transfer fixation. An arm holder was used and positioned on the surgical table on the opposite side of the surgical site to hold the surgical extremity in a relatively flexed and adducted position.

Before we discuss our technique, let's review the relevant anatomy of this case. The pectoralis major possesses 2 heads: the clavicular and sternocostal, named after their location of origin. These insert on the intertubercular sulcus of the humerus. Scapular winging may be medial or lateral. Medial winging is typically caused by serratus anterior palsy due to long thoracic nerve damage, while lateral winging is caused by trapezius palsy or rhomboids palsy. Our patient displayed medial winging due to serratus anterior weakness that interfered with his ability to play sports and complete daily activities. Therefore, for this procedure, we will isolate the sternocostal head, reinforce it with an Achilles allograft, and attach it to the inferior angle of the scapula.

Technique Description

A standard anterior axillary incision over the bikini strap distribution was used to access the deltopectoral interval. The skin was sharply incised with a No. 15 blade, and electrocautery was used to create full-thickness flaps down to the deltopectoral fascia. The interval between the deltoid and the pectoralis major was identified and developed. We retracted the cephalic vein laterally for protection. We then isolated and exposed the insertion of the PMT onto the proximal humerus. The undersurface of the PMT was mobilized through a subpectoral approach using both blunt and sharp dissection. The raphe between the sternal and clavicular heads was identified and developed. We further developed the raphe using a combination of electrocautery and sharp dissection.

Additional blunt dissection allowed for clear visualization of the sternal head of the pectoralis major. The sternal head was isolated and tagged with a Penrose drain to help avoid neurovascular compromise and relieve the tendon of any soft tissue adhesions. A tenotomy of the sternal head of the PMT was then completed sharply under direct visualization. After this, the sternal head was tagged using heavy nonabsorbable sutures. Here, the freely mobile sternal head can be seen; this was prepared for allograft incorporation, while the clavicular head remained in situ.

An Achilles allograft was prepared in a sterile fashion on the back table. The bone block was removed, and the full width of the Achilles allograft was used. The proximal aspect of the Achilles allograft was incorporated into the musculotendinous junction of the split pec major tendon harvest, and the bone block end remained free for transfer. The allograft was introduced into the surgical field and provisionally secured using Alice clamps to reinforce the myotendinous junction. We secured the Achilles allograft to the pectoralis tendon using multiple No. 2 heavy nonabsorbable sutures.

The surgical extremity was then positioned in an arm holder with the patient in the lateral decubitus position. A 4- to 6-cm longitudinal incision was sharply incised overlying the inferomedial border of the scapula. Full-thickness skin and subcutaneous flaps were elevated. The latissimus dorsi and teres major were elevated to allow access to the inferomedial border of the scapula. We then bluntly exposed the anterior aspect of the scapula in preparation for the creation of a bone tunnel facilitating graft passage. An 8-mm reamer was used to drill from posterior to anterior, creating a socket for future graft passage and fixation. We selected this size based on the diameter of our allograft construct.

We used a curved Kelly clamp to carefully develop the interval for graft passage, taking care to remain immediately superficial to the serratus anterior muscle belly. Neurovascular protection was further promoted by aiming the curved Kelly clamp with the curve directed toward the chest wall to remain deep to the axillary and radial nerves, bluntly advancing the instrument until it was safely visualized in the posterior incision. A 90° curved tonsil clamp was then used to pass a passing suture through the reamed aperture to aid in graft passage. A tagging suture applied to the Achilles tendon allograft–PMT construct was shuttled from anterior to posterior. The tendon was then passed through the scapular tunnel aperture in an anterior-to-posterior direction before graft tensioning and final fixation. The arm was positioned in maximal abduction and extension to facilitate graft tensioning. With the patient still in the lateral decubitus position, the tendon transfer, now threaded through the scapular aperture, was tensioned and cycled. Following this initial passage, the graft was passed around the inferomedial border of the scapula, directed anteriorly, laid over the sternal head, and secured using three No. 5 heavy nonabsorbable sutures, completing the split tendon transfer.

Following this procedure, the patient was placed in a sling with an abduction pillow for immobilization. From weeks 0 to 6, supine-only passive range of motion to 90° of forward flexion and 20° of external rotation is allowed, with progressive pendulum exercises permitted under physical therapy supervision. After 6 weeks, the sling may be discontinued, and active range of motion to 140° of forward flexion, 40° of external rotation, and 80° of abduction may be incorporated into rehab. Active range of motion should be advanced as tolerated. From 6 to 12 weeks, goals include full shoulder range of motion and pain-free activities of daily living. Light isometric resistance may be initiated around 8 weeks. At 12 weeks, strengthening through progressive weightbearing and resistance exercises is started. Patients are encouraged to continue with physical therapy until a full return to sport or work activities without restrictions is achieved.

Results

Several complications may occur following this procedure. Graft failure or technical shortcomings can lead to recurrence, particularly in overhead athletes. ² Additionally, care must be taken to avoid neurovascular damage given the proximity of the axillary nerve, radial nerve, medial and lateral pectoral nerves, and axillary vessels. ⁸ Cosmetic chest deformity can occur, which may not be acceptable to patients, and superficial infections are also a risk.^5,7

However, outcomes following split PMT transfers are generally positive, particularly when compared to alternative treatments. Patient-reported outcomes demonstrate significant improvements in pain and American Shoulder and Elbow Surgeons and Constant scores.^6,9 Functionally, PMT transfer has been shown to significantly increase long-term shoulder forward flexion and abduction. ⁶ The procedure has high patient satisfaction rates, with patients demonstrating a willingness to recommend the surgery to others. ⁶ Compared to scapulothoracic fusion—the other widely used procedure for treating scapular winging secondary to long thoracic nerve palsy—PMT transfer optimizes range of motion while possessing a lower complication rate. ² In fact, Geurkink et al ⁶ reported 0 complications among 15 patients who received pec major transfer with Achilles allograft for chronic scapular winging.

Discussion/Conclusion

For this procedure, we recommend tagging the sternal head of the pec major tendon with a drain before the tenotomy. This prevents soft tissue adhesions to the tendon and enhances patient safety during this step of the procedure. When developing the interval for graft passage, we recommend aiming the curved Kelly clamp with the curve facing the chest. Remaining immediately superficial to the serratus anterior protects against damage to the axillary neurovasculature. Finally, before reaming a tunnel, a Darrach or similar retractor can be placed deep or anterior to the inferomedial border of the scapula to protect against plunging.

Our patient was most recently seen at 16 weeks postoperatively. He reports 0 out of 10 pain and is near full range of motion. Active abduction is limited to 90°, with 140° of passive range of motion. We anticipate this will continue to improve with further physical therapy. Thank you for your attention.