Subpectoral Biceps Tenodesis

Surgical Indications

Primary Indications for Subpectoral Tenodesis

• Symptomatic long head of biceps tendinopathy refractory to 3-6 months of non-operative care (activity modification, NSAIDs, corticosteroid injection into the groove)
• Biceps instability or subluxation from the bicipital groove (medial subluxation over the lesser tuberosity on dynamic ultrasound or MRI)
• Partial thickness tears greater than 25-50 percent of tendon diameter with persistent pain
• SLAP tear type II or IV in patients older than 40 years where repair is unlikely to succeed and tenodesis is preferred
• Failed proximal (suprapectoral or arthroscopic) tenodesis with residual groove pain

Tenodesis versus Tenotomy — Decision Thresholds

• Tenodesis preferred when the patient is younger than 60, participates in heavy labour or overhead sport, or strongly desires to avoid cosmetic deformity and cramping.
• Tenotomy acceptable in older, lower-demand patients who accept the 30-50 percent risk of Popeye deformity and occasional cramping.
• Tenodesis eliminates the risk of Popeye deformity and reduces cramping to less than 10 percent; tenotomy carries a 30-50 percent deformity rate and 20-40 percent cramping rate.

Contraindications

Absolute:

• Active infection in the shoulder or axilla
• Inability to comply with postoperative sling and rehabilitation protocol

Relative:

• Severe glenohumeral osteoarthritis where arthroplasty is indicated (consider concomitant tenodesis during arthroplasty)
• Poor bone quality precluding secure fixation (consider alternative fixation or tenotomy)

Evidence Base

Tenodesis versus Tenotomy

Multiple Level I and II studies demonstrate that tenodesis provides superior cosmesis and lower cramping rates with equivalent pain relief and function scores. A 2023 meta-analysis of 12 RCTs found no difference in Constant or ASES scores but a 40 percent absolute risk reduction in Popeye deformity with tenodesis.

Subpectoral versus Suprapectoral Tenodesis

Subpectoral tenodesis removes the entire intra-groove diseased segment. Suprapectoral techniques leave 3-5 cm of tendon in the groove. A 2022 prospective cohort showed 25 percent of suprapectoral patients required revision for residual groove pain versus 4 percent after subpectoral tenodesis. Subpectoral revision resolved symptoms in 87 percent of cases.

Fixation Method Comparison

Interference screw fixation provides the highest load-to-failure in biomechanical studies (greater than 200 N). Cortical button and dual suture anchor techniques are biomechanically acceptable (150-180 N) and have lower risk of tunnel fracture. Clinical outcomes are equivalent across methods when length-tension is restored.

Key Evidence

Relevant Surgical Anatomy for Subpectoral Tenodesis

Bicipital Groove and Long Head of Biceps Tendon

The long head of biceps originates from the supraglenoid tubercle and superior labrum, courses intra-articularly, then enters the bicipital groove beneath the transverse humeral ligament. The intra-groove segment (3-5 cm) is a common site of tendinopathy, partial tearing, and instability. The tendon is extrasynovial within the groove and receives blood supply from branches of the anterior humeral circumflex artery.

Pectoralis Major Insertion and Axillary Fold Landmarks

The pectoralis major inserts on the lateral lip of the bicipital groove. Its inferior border is the key surface landmark for the axillary-fold incision. The inferior 2-3 cm of pectoralis major must be released or retracted superiorly to expose the groove. The deltoid inserts laterally and is not violated in this approach.

Neurovascular Structures at Risk

Musculocutaneous nerve:

• Emerges from the lateral cord 5-8 cm distal to the coracoid.
• Pierces coracobrachialis 3-5 cm medial to the tenodesis site.
• Continues distally as the lateral cutaneous nerve of the forearm.
• Protection: Limit medial retraction; the nerve is vulnerable to stretch injury from aggressive medial force.

Axillary nerve:

• Courses around the surgical neck 2-3 cm superior to the inferior border of pectoralis major.
• Lies deep to the deltoid fascia.
• Protection: Stay inferior to the pectoralis major border; avoid superior retraction beyond this landmark.

Radial nerve and profunda brachii artery:

• Lie in the spiral groove on the posterior humerus.
• Approximately 2-3 cm medial and deep to the anterior tenodesis site.
• Protection: Direct visualisation during drilling; use a drill stop; avoid posterior cortical penetration.

Length-Tension Relationship

The anatomic resting length places the superior border of the biceps muscle belly at the inferior border of the pectoralis major insertion when the arm is adducted at the side in neutral rotation. This landmark is used intraoperatively to set tendon tension. Over-tensioning produces a high-riding muscle belly and anterior shoulder pain; under-tensioning produces residual groove symptoms and cosmetic deformity.

Positioning and Preparation

Patient position: Beach-chair position with the arm in slight abduction and neutral rotation on a padded arm board. The shoulder is prepped and draped to allow free movement. A sterile tourniquet is not required.

Anaesthesia: General anaesthesia with interscalene block for postoperative analgesia. Local infiltration with 0.25 percent bupivacaine with epinephrine along the planned incision provides vasoconstriction.

Consent: Discuss risks including nerve injury (musculocutaneous, axillary, radial — less than 1 percent each), humeral fracture (1 percent), fixation failure (2-4 percent), residual groove pain (3-6 percent), infection (less than 1 percent), and cosmetic dissatisfaction.

Open Subpectoral Biceps Tenodesis — Step-by-Step

Step 1: Incision and Superficial Exposure

Make a 4-5 cm incision in the axillary fold, centred over the inferior border of the pectoralis major. Incise skin and subcutaneous fat. Identify the inferior border of pectoralis major. Develop the plane between pectoralis major and the short head of biceps using blunt dissection. Retract pectoralis major superiorly with a Hohmann retractor placed on the humeral shaft just inferior to the groove.

Step 2: Nerve Identification and Protection

Before deep dissection, identify or protect the musculocutaneous nerve medially. The nerve is usually not visualised but is protected by limiting medial retraction. Identify the axillary nerve superiorly by palpation or direct visualisation if superior retraction is required. The radial nerve is protected by staying anterior and using a drill stop later.

Step 3: Expose and Release the Biceps Tendon

Identify the bicipital groove by palpation. Open the groove sheath longitudinally. Identify the long head of biceps tendon. Release any remaining groove attachments and deliver the entire intra-groove tendon segment into the wound. Resect the intra-articular and groove portions, leaving a 2-3 cm stump for tenodesis.

Step 4: Prepare the Humeral Tunnel

Centre the tunnel on the anterior cortex at the inferior border of the bicipital groove. Drill a unicortical 7-8 mm tunnel perpendicular to the cortex to a depth of 15-20 mm. Use a drill stop to prevent posterior cortical penetration. Clear the tunnel of debris. If using a cortical button, create a second smaller hole 1 cm distal for button passage.

Step 5: Set Length-Tension and Secure Fixation

Mark the tendon at the level that will place the superior border of the biceps muscle belly at the inferior border of pectoralis major with the arm at the side. Pass the tendon through the tunnel or secure with the chosen method (interference screw, cortical button, or dual suture anchors). Confirm the muscle belly position matches the landmark before final fixation.

Interference screw technique (preferred):

• Whipstitch the tendon end with heavy non-absorbable suture.
• Insert the tendon into the tunnel to the marked level.
• Advance a 7-8 mm PEEK or bioabsorbable interference screw alongside the tendon.
• Confirm the screw is flush with the cortex and the tendon is securely fixed.

Cortical button technique:

• Pass the button through the tunnel and flip it on the posterior cortex.
• Tension the sutures to seat the tendon at the correct length.
• Tie the sutures over the button.

Dual suture anchor technique:

• Place two 2.9 mm or 3.5 mm anchors proximal and distal to the tunnel.
• Secure the tendon with mattress sutures to restore length-tension.

Step 6: Wound Closure

Irrigate the wound. Confirm haemostasis. Close the subcutaneous layer with absorbable suture. Close skin with running subcuticular absorbable suture or interrupted nylon. Apply sterile dressing and place the arm in a sling.

Postoperative Protocol

Phase 1: Protection (Weeks 0-4)

• Sling immobilisation at all times except for hygiene and pendulum exercises
• Pendulum exercises begin day 1
• No active elbow flexion or supination against resistance
• Wound check at 10-14 days; suture removal if non-absorbable

Phase 2: Early Motion (Weeks 4-8)

• Discontinue sling at 4 weeks
• Begin active-assisted elbow flexion and supination
• Gentle shoulder ROM exercises
• No lifting greater than 2 kg

Phase 3: Strengthening (Weeks 8-12)

• Progressive resistance exercises for elbow flexion and supination
• Begin light resistance (theraband, 1-2 kg)
• Return to light desk work

Phase 4: Return to Activity (Weeks 12-24)

• Gradual return to full activities
• Heavy labour or overhead sport at 4-6 months when strength is 80 percent of contralateral
• Contact sport or heavy lifting at 6 months

Rehabilitation Pearls

• Early active elbow flexion is the most common cause of fixation failure — protect for 4 weeks
• Length-tension mismatch pain typically presents at 6-12 weeks when strengthening begins
• Persistent groove pain at 3 months warrants groove injection before considering revision