High Yield Overview

DISTAL BICEPS TENDON REPAIR

Single anterior (preferred) or two-incision technique | Intermediate difficulty

Critical Danger Structures

Lateral Antebrachial Cutaneous Nerve

Most commonly injured nerve. Location: Terminal branch of musculocutaneous, crosses antecubital fossa superficially - identify and protect in subcutaneous tissue

Posterior Interosseous Nerve (PIN)

Protected by SUPINATION. Location: Crosses radial neck in pronation - full supination rotates tuberosity anteriorly and moves PIN posterolaterally away from surgical field

Radial Artery

Medial in antecubital fossa. Location: Lies medial to biceps tendon in antecubital fossa - retract medially during exposure

Superficial Radial Nerve

Travels with radial artery. Location: Runs with radial artery, then branches laterally - can be injured with aggressive lateral retraction

Mnemonic

RUPTURERUPTURE - Distal Biceps Clinical Features

Memory Hook:Hook test is most specific - if you can't hook a finger under the biceps tendon, it's completely ruptured

Mnemonic

BUTTONBUTTON - Cortical Button Fixation Steps

Memory Hook:Button provides strongest fixation (~250N) - stronger than suture anchors (~150N) or interference screws

Absolute Indications for Surgery:

Complete distal biceps tendon rupture
Active patient requiring full supination/flexion strength
Acute rupture (<4 weeks optimal timing)
Failed non-operative treatment (partial tears)

Relative Indications:

Partial tears (>50%) failing conservative treatment
High-demand athletes or manual workers
Chronic rupture in active patient (may need graft)

Non-Operative Consideration:

Elderly, sedentary patients accepting strength loss
Significant comorbidities increasing surgical risk
Low-demand patients who accept 30-40% supination weakness

Anatomy

Biceps Tendon Anatomy

Insertion:

Radial tuberosity (ulnar aspect)
Footprint approximately 22mm × 11mm
Short head inserts more distally
Long head inserts more proximally on tuberosity

Function:

Primary supinator of forearm (most powerful)
Secondary elbow flexor
Loss of biceps = 30-40% supination strength loss, 10-20% flexion loss

Key Neurovascular Relationships

Lateral Antebrachial Cutaneous Nerve (LABCN):

Terminal branch of musculocutaneous nerve
Emerges lateral to biceps in distal arm
Crosses antecubital fossa superficially
Most commonly injured nerve in distal biceps repair

Posterior Interosseous Nerve (PIN):

Branch of radial nerve
Crosses radial neck in pronation
SUPINATION protects PIN - moves tuberosity anteriorly, PIN posterolaterally
Danger zone with two-incision technique

Radial Recurrent Artery:

Leash of vessels near radial tuberosity
Must be cauterized for exposure

Critical Yield Data

Supination Loss

Flexion Loss

Optimal Timing

Operative Technique - Single Anterior Incision

Step 1: Patient Positioning

Position:

Supine on operating table
Arm on arm board, supinated
Arm tourniquet (upper arm) or forearm tourniquet
Elbow extended or slightly flexed

Exam Pearl

Technical Tip: Forearm tourniquet allows assessment of tendon excursion if needed. Arm tourniquet provides bloodless field throughout.

Step 2: Skin Incision

Single anterior (Boyd-Anderson modified):

Transverse or oblique incision in antecubital fossa
Approximately 3-4cm, centered over biceps tendon
Can extend proximally if tendon retracted
Transverse incision follows Langer's lines (better cosmesis)

Incision Placement

Stay lateral to brachial artery pulse
Avoid crossing flexion crease (risk of contracture)
May need second proximal incision if tendon very retracted

Step 3: Superficial Dissection

Identify and protect LABCN:

LABCN crosses antecubital fossa superficially
Emerges lateral to biceps, runs medially
MOST COMMON nerve injury - identify early
Retract and protect throughout

Develop interval:

Between brachioradialis (lateral) and pronator teres (medial)
Identify radial artery - retract medially
Biceps tendon stump visible in this interval

Exam Pearl

Technical Tip: If you don't see LABCN, you haven't looked hard enough. It crosses the field in almost all patients - identify and protect it before deep dissection.

Step 4: Tendon Retrieval

Locate and retrieve biceps tendon:

Usually retracted to antecubital crease or above
May need proximal incision if significantly retracted
Use finger dissection to free tendon from adhesions
Deliver tendon through distal wound

Tendon preparation:

Debride frayed end minimally (preserve length)
Whipstitch with high-strength suture (FiberWire)
Krackow or locking whipstitch pattern
Leave suture tails for button passage

Chronic Ruptures

If tendon won't reach tuberosity without tension, consider:
- More extensive release of lacertus fibrosus
- Graft reconstruction (Achilles allograft)
Do NOT repair under excessive tension

Step 5: Expose Radial Tuberosity

Position forearm:

FULL SUPINATION - critical for PIN protection
Supination rotates tuberosity anteriorly
Moves PIN to posterolateral, away from surgical field

Clear tuberosity:

Identify radial tuberosity on anteromedial radius
Clear soft tissue from tuberosity footprint
Cauterize radial recurrent vessels (leash of Henry)
Visualize entire footprint

Exam Pearl

Technical Tip: SUPINATION is the key safety maneuver. The PIN wraps around the radial neck in pronation - full supination moves it away from your instruments by rotating the tuberosity anteriorly.

Step 6: Prepare Tuberosity

For cortical button fixation:

Place guide pin at center of tuberosity footprint
Confirm position with image if desired
Drill unicortical with appropriately sized cannulated drill
Complete drilling through far cortex
Ensure button will pass and flip

Socket preparation (optional):

Create unicortical socket at tuberosity to seat tendon
Improves bone-tendon contact
Do not make socket too deep (weakens bone)

Drilling Hazards

Keep forearm SUPINATED during drilling
Drill perpendicular to radius
Protect soft tissues with retractors
Do not plunge through far cortex aggressively

Step 7: Button Passage and Fixation

Thread button:

Pass tendon sutures through button eyelet
Insert button into drill hole
Push through to far cortex
Flip button by pulling on sutures (feel "pop")

Confirm button engagement:

Tug on sutures - should feel solid
Fluoroscopy if any doubt
Button should be flush on far cortex

Exam Pearl

Technical Tip: The "pop" when the button flips is reassuring. If you don't feel it, image to confirm the button is through and flipped. An unflipped button will pull out.

Step 8: Tendon Docking and Tensioning

Dock tendon into socket:

Pull tendon into tuberosity socket
Tension with elbow at 30-40° flexion, forearm supinated
Tendon should reach tuberosity without excessive tension

Assess tension:

Should allow full elbow extension without gap
Should not create flexion contracture
Check pronation/supination ROM

Tension Errors

Over-tensioning = flexion contracture, limited extension
Under-tensioning = weakness, incomplete healing
Target: full extension possible with tendon engaged

Step 9: ROM Check and Hemostasis

Intraoperative testing:

Full elbow extension - tendon should remain docked
Full flexion - no impingement
Full pronation and supination - smooth, no catching

Hemostasis:

Release tourniquet
Bipolar cautery for bleeding points
Ensure no hematoma formation

Step 10: Closure

Layered closure:

Close deep fascia if possible (not tight)
Subcutaneous absorbable sutures
Skin closure (nylon or absorbable)
Sterile dressing

Immobilization:

Posterior splint at 90° elbow flexion
Forearm in neutral to slight supination
Early motion protocol starts 1-2 weeks

Two-Incision Technique

Indications for Two-Incision Approach

Consider when:

Anatomic footprint restoration desired
Chronic rupture requiring extensive exposure
Revision surgery
Surgeon preference/training

Technique Differences

Anterior incision:

Same as single incision for tendon retrieval
Smaller incision may be used

Posterior incision (muscle-splitting):

Made over posterior radius, lateral to ulna
Split common extensor muscles
Expose radial tuberosity from posterior
Creates bone tunnels or uses suture anchors

Heterotopic Ossification Risk

Higher with two-incision technique:

Reported in 15-50% of cases
Usually asymptomatic
Can cause significant stiffness or synostosis
Modified technique (muscle splitting vs subperiosteal) reduces risk

Single vs Two-Incision Technique

Fixation Options

Distal Biceps Fixation Methods

Exam Pearl

Exam Key: Cortical button provides the strongest fixation (~250N ultimate strength), allowing earlier and more aggressive rehabilitation. It is now the preferred fixation method for most surgeons.

Complications

Distal Biceps Repair Complications

Nerve Injury Details

LABCN (most common):

Incidence: 10-25% transient, 1-5% permanent
Causes lateral forearm numbness
Usually resolves with observation
Prevention: identify early, protect carefully

PIN:

Incidence: 1-3%
Causes finger extension weakness
SUPINATION is protective
Most recover with observation

Critical Yield Data

LABCN Injury

HO (Single Incision)

Re-rupture

Post-operative Care

Immediate Post-operative

Immobilization:

Posterior splint at 90° elbow flexion
Forearm in neutral to slight supination
Duration: 1-2 weeks

Early Rehabilitation (Weeks 1-6)

Week 1-2:

Splint immobilization
Finger and wrist ROM
Gentle elbow ROM out of splint (passive extension, active flexion)

Week 2-4:

Remove splint
Progressive active ROM
Avoid terminal extension (limit to -30°)
NO resisted supination

Week 4-6:

Progress to full ROM
Gentle active supination
Light ADLs

Intermediate Rehabilitation (Weeks 6-12)

Week 6-8:

Begin isometric strengthening
Light resisted supination
Progress ROM

Week 8-12:

Progressive resistance training
Concentric then eccentric loading
Sport-specific activities begin

Return to Activity

Light desk work: 2-4 weeks
Light manual work: 6-8 weeks
Heavy manual work: 12-16 weeks
Full sports: 4-6 months
Expected outcomes: 95%+ satisfaction, near-normal strength

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"A 42-year-old manual laborer presents with pain and weakness 24 hours after feeling a 'pop' in his elbow while lifting. On examination, you cannot hook your finger under the biceps tendon. How would you manage this patient?"

EXCEPTIONAL ANSWER

This clinical picture is consistent with a complete distal biceps tendon rupture. The history of a pop during eccentric loading and inability to hook the tendon (positive Ruland's hook test) are highly specific for complete rupture. I would confirm with MRI to assess tendon retraction and quality. Given he is an active manual laborer, I would recommend surgical repair. Timing is important - within 3-4 weeks is optimal for primary repair. Beyond this, the tendon retracts and may require graft reconstruction. I would use a single anterior incision approach with cortical button fixation, which provides the strongest fixation and allows early motion. Key technical points: identify and protect LABCN, maintain full supination to protect PIN, whipstitch tendon, create appropriate socket at tuberosity, and dock tendon at 30-40° flexion. Post-operatively, splint at 90° for 1-2 weeks, then progressive ROM, avoiding resisted supination for 6 weeks. Expected outcome is excellent with return to full manual work by 3-4 months.

VIVA SCENARIOStandard

EXAMINER

"Explain why forearm supination is critical during distal biceps repair and how it protects the posterior interosseous nerve."

EXCEPTIONAL ANSWER

Forearm supination is the key safety maneuver during distal biceps repair. The posterior interosseous nerve, which is the motor branch of the radial nerve, wraps around the radial neck as it passes from the anterior to posterior compartment through the supinator muscle. In pronation, the radial tuberosity faces posteriorly, and the PIN lies directly over or adjacent to it - placing the nerve at high risk during tuberosity exposure and drilling. When the forearm is fully supinated, the radial tuberosity rotates to face anteromedially, directly toward our single anterior incision. Simultaneously, the PIN rotates posterolaterally, moving away from our surgical field. This simple positioning maneuver dramatically reduces the risk of PIN injury. I maintain full supination throughout tuberosity exposure, preparation, drilling, and button placement. If the patient's supination is limited, I have an assistant maintain maximal supination while I work on the tuberosity.

VIVA SCENARIOStandard

EXAMINER

"A patient develops complete loss of finger and thumb extension 2 weeks after distal biceps repair. How would you assess and manage this?"

EXCEPTIONAL ANSWER

This presentation is concerning for posterior interosseous nerve injury. The PIN innervates the finger extensors (EDC) and thumb extensors (EPL, EPB), so complete loss of extension suggests significant nerve involvement. First, I would carefully examine to confirm the deficit is isolated to PIN territory - wrist extension should be preserved (ECRL/ECRB innervated more proximally). I would also check for any sensory changes, which would suggest more proximal radial nerve injury. Initial management is observation with splinting to prevent extensor lag. I would obtain EMG/NCS at 6 weeks to assess whether there is any innervation, then repeat at 3 months. Most PIN injuries are neurapraxia from retraction or thermal injury and recover spontaneously within 3-6 months. If there is no clinical or electrical recovery by 4-6 months, I would explore the nerve. At exploration, I would release any scar or constriction, and if there is a neuroma-in-continuity, I would consider neurolysis. Complete transection is rare but would require nerve grafting. During the recovery period, I would use a dynamic extension splint and hand therapy to maintain joint mobility.

Distal Biceps Tendon Repair - Exam Summary

High-Yield Exam Summary

References

Grewal R, et al. Single versus double-incision technique for the repair of acute distal biceps tendon ruptures: A randomized clinical trial. J Bone Joint Surg Am. 2012;94(13):1166-1174.
Recordon JA, et al. Repair of acute distal biceps tendon ruptures using cortical button vs interference screw fixation: A randomized controlled trial. J Shoulder Elbow Surg. 2015;24(3):e57-e62.
Chavan PR, et al. Repair of the ruptured distal biceps tendon: A systematic review. Am J Sports Med. 2008;36(8):1618-1624.
Kodde IF, et al. Distal biceps repair: A systematic review of reoperation and re-rupture rates. J Shoulder Elbow Surg. 2018;27(8):1455-1463.
Bain GI, et al. Repair of distal biceps tendon rupture: A new technique using the Endobutton. J Shoulder Elbow Surg. 2000;9(2):120-126.
Kelly EW, et al. Complications of repair of the distal biceps tendon with the modified two-incision technique. J Bone Joint Surg Am. 2000;82(11):1575-1581.
Dunphy TR, et al. Surgical treatment of distal biceps tendon ruptures: An anatomic and clinical review. J Shoulder Elbow Surg. 2017;26(12):2172-2180.
Schmidt CC, et al. The role of supination in distal biceps tendon repair. J Shoulder Elbow Surg. 2015;24(7):1093-1098.
O'Driscoll SW, et al. The clinical anatomy of the biceps tendon insertion. J Shoulder Elbow Surg. 2007;16(5):e6-e11.
Nesterenko S, et al. Distal biceps tendon repair: Clinical outcomes of surgical treatment. J Shoulder Elbow Surg. 2010;19(2 Suppl):2-8.