Rotator Cuff Repair: Single vs Double Row

The debate between Single-Row (SR) and Double-Row (DR) rotator cuff repair is one of the most enduring controversies in shoulder surgery. It pits the physicist against the pragmatist. On paper and in the lab, the double-row repair is undeniably superior. It is stronger, covers more area, and suppresses fluid motion. Yet, in the clinic, patient outcomes often fail to show a difference.

This article dissects the anatomy, biomechanics, economics, and clinical evidence to help you decide which technique to use and when.

Visual Element: High-fidelity illustration of the "Suture Bridge" (Transosseous Equivalent) technique vs a Simple Single Row repair, highlighting the footprint coverage area.

1. The Anatomy of the Footprint

To understand the repair, we must understand the target. The rotator cuff insertion (footprint) on the greater tuberosity is not a line, but a broad area.

• Supraspinatus Footprint: Approximately 25mm long (anterior-posterior) and 15mm wide (medial-lateral).
• The Goal: Ideally, a repair should restore the tendon to this entire surface area to maximize the potential for healing (Sharpey's fibers).

2. Single-Row Repair (SR)

Technique: Anchors are placed in a single line, usually at the lateral aspect of the footprint or slightly medialized. Sutures are passed through the tendon and tied.

• Simple Stitch: One point of fixation.
• Mattress Stitch: Broader hold, slightly better compression.

Pros:

• Speed: Faster operative time.
• Cost: Uses fewer anchors (typically 1-2).
• Vascularity: Less strangulation of the tendon microvasculature.
• Revision: If it fails, there is more bone stock left for a revision.

Cons:

• "Windshield Wiper" Effect: The tendon can toggle around the single line of fixation.
• Synovial Fluid Leakage: It often fails to seal the footprint, allowing synovial fluid to seep between the tendon and bone, which inhibits healing.
• Limited Footprint Coverage: Re-creates only a portion of the native insertion.

3. Double-Row Repair (DR) and Suture Bridge

Technique:

1. Medial Row: Anchors placed at the articular margin.
2. Lateral Row: Anchors placed at the lateral cortex.
3. Suture Bridge (Transosseous Equivalent - TOE): The sutures from the medial row are spanned across the tendon and secured with the lateral anchors, compressing the tendon against the bone like a seatbelt.

Pros:

• Footprint Restoration: Covers nearly 100% of the native footprint.
• Contact Pressure: Generates high, uniform compressive force.
• Water-Tight Seal: Prevents synovial fluid intrusion.
• Biomechanics: Significantly higher load-to-failure and stiffness.

Cons:

• Cost: Uses 3-4 anchors (double the implant cost).
• Time: Technically more demanding.
• Strangulation Risk: Excessive tension/compression can cut off blood supply to the tendon edge (Type 2 failure: medial cuff failure).

Visual Element: Comparison table with "footprint coverage" diagrams and force vector arrows.

4. The Clinical Disconnect: Why doesn't DR always win?

If DR is biomechanically perfect, why don't all studies show it's clinically better? This is the "Biomechanics vs. Biology" paradox.

The Evidence Summary

• Small/Medium Tears (<3cm): Level I evidence consistently shows NO difference in functional outcomes (ASES, Constant scores) or pain between SR and DR. A well-done single row is "strong enough" for these tears.
• Large/Massive Tears (>3cm): This is where DR shines. Studies show significantly lower re-tear rates with double-row repair.
• Does Re-tear Matter?: Surprisingly, many patients with a structural re-tear (on ultrasound/MRI) still have good clinical function. However, they are weaker. A healed tendon generally provides better strength than a re-torn one.

Evidence Corner: The OASIS trial and other meta-analyses suggest that while functional scores may be similar, the re-tear rate for DR is roughly half that of SR (e.g., 25% vs 50% for large tears).

5. Cost-Utility Analysis

In an era of value-based care, cost matters.

• A DR repair adds approximately $1,000 - $1,500 USD in implant costs per case.
• To justify this cost, the technique must prevent re-operations or significantly improve function.
• For a small tear, spending this extra money provides no measurable benefit = Low Value.
• For a large tear in an active patient, preventing a revision surgery (which costs thousands) = High Value.

6. Decision-Making Algorithm

When should you choose which?

Go Single-Row if:

• Tear size is Small (<1cm) or Medium (1-3cm).
• Partial thickness tears (PASTA) converted to full.
• Elderly/Low-demand patient (Goal is pain relief, not strength).
• Poor bone stock (lateral cortex cysts) where lateral anchors might pull out.

Go Double-Row (Suture Bridge) if:

• Tear size is Large (>3cm) or Massive.
• Young, active patient / Laborer / Athlete.
• Good tissue quality (the tendon can hold the sutures without ripping).
• Revision cases (if bone stock permits).

7. The "Triple Row" and Future Directions

Some surgeons advocate for even more complex constructs, or adding biological augments (patches, grafts) to the double-row repair. The concept is to move from purely mechanical fixation to "bio-inductive" repair. However, the law of diminishing returns applies. Adding a 5th or 6th anchor rarely adds meaningful strength and only adds cost/trauma.

Conclusion

The "Single vs. Double" debate is not a binary choice; it is a spectrum of indications.

• Single-Row is not "inferior"; it is appropriate, cost-effective, and successful for the majority of routine tears.
• Double-Row is the "heavy duty" option. It provides the mechanical stability required for large tears and high-demand tissues.

The master surgeon does not force every patient into a "one-size-fits-all" construct but matches the biomechanical solution to the biological problem.

Clinical Pearl: The Knotless Lateral Row. In Suture Bridge repairs, using knotless anchors for the lateral row is standard. It eliminates prominent knots on the greater tuberosity which can cause subacromial impingement and abrasion, and it is generally faster.