Isolated Bioinductive Arthroscopic Repair of Partial-Thickness Rotator Cuff Tears Using a Resorbable Collagen Implant
Authors: Thangarajah Tanujan , Ling Ferraby K. , Lo Ian K. 
Published: January 2022

Background:
Over 300,000 rotator cuff repairs are performed annually in the United States, where the annual financial burden of managing shoulder pain has been estimated to be $3 billion. Despite advances in surgical techniques, retear rates range from 39% to 94%
4
. Partial-thickness tears are approximately twice as common as full-thickness tears and can lead to considerable pain and loss of function. Although some partial-thickness tears can be treated nonoperatively, spontaneous healing is unlikely when >50% of the bursal/articular-sided tendon thickness is involved, and thus nonoperative treatment would be unsuccessful
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. Regeneten (Smith & Nephew) is a bioinductive type-1 collagen implant that can be utilized to repair a partial-thickness rotator cuff tear without formal tendon-bone reattachment. Because this implant does not require tendon-bone reattachment, treatment does not typically entail prolonged rehabilitation. At 2 years postoperatively, this implant has been shown to significantly improve functional outcomes and tendon thickness without any serious adverse events
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.

Description:
A diagnostic arthroscopy is performed via a posterior viewing portal, paying particular attention to the insertion of the posterosuperior rotator cuff onto the humeral head. The subacromial space is entered posteriorly and visualized. With use of electrocautery through a lateral portal, all soft tissue is cleared from the undersurface of the acromion and from the superficial rotator cuff. The coracoacromial ligament is released from the underside of the acromion, and an acromioplasty is performed if indicated. The partial-thickness rotator cuff tear is visualized and examined for tissue quality, tear area, and residual tendon thickness. The size of the tear is measured, and an appropriate implant size is chosen. The lateral portal is enlarged so that the graft can be inserted and unfolded with use of a specialized delivery guide. The implant is centered over the tear, ensuring that it covers as much of the lateral footprint as possible. To complete the procedure, the implant is secured to the tendon with use of soft-tissue staples and to the lateral osseous footprint with use of bone staples.

Alternatives:
First-line treatment is often nonoperative and entails activity modification, pharmacological therapies, and targeted physiotherapy directed toward strengthening parascapular muscles and the remaining rotator cuff. Surgical treatment is considered for persistent symptoms. Conventional operative strategies include subacromial decompression, rotator cuff debridement, in situ repair, and conversion to a full-thickness defect and repair.

Rationale:
Partial-thickness tears substantially increase intratendinous strain. This increased strain leads to further tissue degeneration and tear enlargement
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, likely influencing the high rate of tear propagation observed with nonoperative treatment and nonanatomic operative treatment, such as subacromial decompression. Isolated bioinductive repair of partial-thickness tears with use of a resorbable collagen implant does not involve tendon excision or repair of the tendon to the bone, which can sometimes be challenging. This technique offers a simple solution to a complex problem and has the benefit of an accelerated rehabilitation program compared with formal rotator cuff repair. Accordingly, patient satisfaction with the procedure is high, making this treatment an appealing option
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.

Expected Outcomes:
Short and midterm results following isolated bioinductive repair of partial-thickness tears demonstrate that it is a safe procedure associated with a reduction in pain, increased range of motion, and improvement in functional outcomes. Patients should be counselled regarding the safety of a resorbable collagen patch and its potential to promote healing and improve symptoms
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Important Tips:

Acronyms and Abbreviations:

MRI = magnetic resonance imagingPEEK = polyetheretherketoneVAS = visual analogue scaleASES = American Shoulder and Elbow Surgeons Shoulder Score