Orthopaedic Surgery - Pectoralis Major Tendon Rupture

Basics

Pectoralis major tendon rupture is an injury involving the pectoralis major muscle-tendon unit, most commonly near its insertion on the proximal humerus.

The pectoralis major contributes importantly to:

Shoulder adduction

Internal rotation

and

Forward flexion, particularly through the clavicular head.

The sternocostal portion contributes strongly to:

Adduction and internal rotation.

Anatomy

The pectoralis major originates from:

Clavicle

Sternum

Upper ribs and costal cartilages

External oblique aponeurosis

The tendon inserts on the proximal humerus along the:

Lateral lip of the intertubercular groove, or crest of the greater tubercle.

Tendon Orientation

The tendon has a twisted configuration.

The lower sternocostal fibers rotate before insertion so that the inferior fibers insert relatively:

More proximally on the humerus.

This complex orientation is important during:

Surgical reconstruction.

Classification

Pectoralis major injuries may be classified by severity.

Type I

Muscle strain or microscopic tearing.

The structural continuity of the muscle-tendon unit remains intact.

Type II

Partial tear.

Only a portion of the muscle or tendon is disrupted.

Type III

Complete rupture.

There is complete disruption of the affected component of the pectoralis major muscle-tendon unit.

Classification by Location

Injuries may also be described according to location:

Muscle origin

Muscle belly

Musculotendinous junction

Tendon substance

Humeral insertion

The most common complete ruptures occur near the:

Humeral tendon insertion

or

Musculotendinous junction.

Prevention

Preventive measures include:

Avoiding sudden excessive loads during heavy bench pressing

Using progressive resistance training

Maintaining proper lifting technique

Avoiding anabolic-androgenic steroid misuse

The risk is particularly high when the arm is heavily loaded in:

Extension and external rotation.

Epidemiology

Pectoralis major rupture occurs predominantly in:

Men in their 20s to 40s.

It is strongly associated with:

Athletic and resistance-training activities.

Sports Association

A large proportion of injuries occur during:

Weight lifting

particularly:

Bench press

Other reported activities include:

Wrestling

Jujitsu

Gymnastics

Contact sports

Incidence

The true incidence is:

Unknown

but recognition has increased as participation in high-intensity resistance training has become more common.

Risk Factors

Important risk factors include:

Heavy resistance training

Power lifting

Bench pressing

Anabolic steroid use

Anabolic Steroids

Anabolic steroids have been proposed to increase rupture risk through:

Disproportionately rapid increases in muscle strength

and possible alterations in:

Tendon structure and stiffness.

The resulting imbalance between muscular force production and tendon capacity may predispose to failure.

Pathophysiology

The clinical consequences depend on:

The location

Extent

and

Chronicity

of the tear.

Partial injuries are often:

Intramuscular

or located at the:

Musculotendinous junction.

Complete ruptures most commonly occur near:

The tendon insertion on the humerus.

Etiology

Strains and Partial Tears

These are more common than complete ruptures.

They may involve:

Muscle fibers

Musculotendinous junction

or a portion of the tendon.

Complete Rupture

Complete rupture usually results from:

Sudden forceful overload of an eccentrically contracting pectoralis major.

The classic mechanism occurs during the:

Lowering phase of a heavy bench press.

Bench-Press Mechanism

The muscle is placed under maximal tension when the shoulder is:

Extended

Abducted

and

Externally rotated.

A sudden overload in this position may cause:

Avulsion of the tendon from its humeral insertion.

Diagnosis

Diagnosis is usually based primarily on:

History

and

Physical examination.

Imaging is particularly useful when the diagnosis is uncertain or surgical treatment is being considered.

Signs and Symptoms

Patients often report:

Sudden severe pain in the anterior shoulder, chest, or upper arm

at the moment of injury.

Audible Pop

Many patients describe:

A snap or pop

at the time of rupture.

Acute Findings

Other common symptoms include:

Swelling

Bruising

Weakness

Painful or limited shoulder motion

History

Important questions include:

What activity was being performed?

Was a heavy bench press involved?

Was there a sudden eccentric load?

Was a pop heard or felt?

Did immediate bruising or deformity develop?

Does the patient use anabolic steroids?

Physical Examination

Inspection

Inspection may reveal:

Swelling

Ecchymosis

Anterior chest-wall hematoma

Axillary bruising

Upper-arm bruising

Anterior Axillary Fold

A complete rupture may cause loss or thinning of the:

Anterior axillary fold.

The affected side may demonstrate:

Flattening

A visible sulcus

or

Asymmetry compared with the opposite side.

Deltopectoral Groove

A visible depression may develop along the:

Deltopectoral region

because of tendon retraction.

Muscle Bunching

When the patient contracts the muscle, the pectoralis major may:

Retract medially

creating a visible or palpable bulge closer to the chest wall.

Palpable Defect

A complete rupture may produce a:

Distinct palpable gap

between the retracted muscle-tendon unit and the humeral insertion.

This finding is more suggestive of a full-thickness tear than a partial injury.

Tenderness

Tenderness is often maximal near the:

Humeral tendon insertion

or

Anterior axillary fold.

Strength Testing

Manual testing usually demonstrates weakness of:

Shoulder adduction

and

Internal rotation.

Forward flexion may also be weakened.

Comparison With Contralateral Side

The opposite side should be examined for comparison of:

Axillary contour

Muscle tension

Strength

Palpable tendon continuity

Imaging

Plain Radiographs

Plain radiographs are useful initially to exclude:

Proximal humeral fracture

Other bony injury

and, rarely,

Bony avulsion from the humeral insertion.

Radiographs are usually normal in isolated soft-tissue rupture.

Ultrasonography

Ultrasound can help identify:

Tendon discontinuity

Hematoma

Retraction

Location of the tear

It is:

Rapid

Relatively inexpensive

and

Dynamic

but is highly dependent on:

Operator experience.

MRI

MRI is the preferred advanced imaging modality when precise characterization is required.

It can determine:

Partial versus complete rupture

Location of the tear

Degree of tendon retraction

Acute versus chronic changes

Muscle quality

MRI Field of View

Routine shoulder MRI may not adequately visualize the entire pectoralis major.

The examination should include:

The anterior chest wall, axilla, and humeral insertion.

A dedicated pectoralis major MRI protocol is often preferable.

Acute MRI Findings

Acute tears may demonstrate:

Tendon discontinuity

Edema

Hemorrhage

Hematoma

Retraction of the muscle-tendon unit

Chronic MRI Findings

Chronic injuries may show:

Scar tissue

Tendon retraction

Muscle atrophy

Fatty change

These findings help determine whether primary repair remains feasible.

Diagnostic Procedures

Pectoralis major rupture is often diagnosed:

Clinically.

MRI is particularly valuable for:

Confirming tear pattern

and

Planning surgery.

Pathological Findings

At surgery, findings may include:

Torn tendon fibers

Torn muscle fibers

Hematoma

Scar tissue in chronic injuries

Chronic Changes

Delayed presentation may result in:

Tendon shortening

Scar formation

Muscle atrophy

and occasionally

Poor tissue quality.

Differential Diagnosis

Important alternatives include:

Pectoralis major muscle strain

Partial pectoralis major tear

Proximal humerus fracture

Coracoid avulsion fracture

Anterior shoulder injury

Treatment

Management may be:

Nonoperative

or

Operative

depending on:

Extent of injury

Location

Age

Functional demand

Cosmetic expectations

Initial Stabilization

During the acute phase, the arm may be supported in:

A sling

or

Sling and swathe.

Initial treatment also includes:

Ice

Analgesia

Control of swelling and hematoma

Nonoperative Treatment

Nonoperative treatment may be appropriate for:

Contusions

Muscle strains

Partial tears

Muscle-belly tears

Low-demand or sedentary patients with complete tears

Goals of Nonoperative Care

Management includes:

Rest

Temporary sling immobilization

Pain control

Ice

Gradual restoration of motion

Expected Results of Nonoperative Treatment

Patients may regain:

Useful functional motion

and satisfactory daily function.

However, complete tears treated nonoperatively often result in persistent:

Loss of adduction strength

Reduced internal-rotation strength

Loss of shoulder flexion strength

Visible cosmetic deformity

Individualized Decision-Making

Treatment should reflect the patient’s:

Age

Occupation

Sports requirements

Functional demands

Cosmetic concerns

A sedentary older adult may reasonably prefer nonoperative care, whereas:

Competitive athletes and high-demand individuals

often benefit from operative repair.

Nonoperative Rehabilitation

Passive and active motion may begin relatively early as pain allows.

A typical progression includes:

Gentle range of motion during the first several weeks

followed by

Progressive strengthening once pain-free motion is restored.

Strengthening

Light resistance may begin at approximately:

6–8 weeks

when symptoms and healing permit.

Resistance is then gradually increased.

Return to Heavy Training

Progression toward heavier resistance may occur around:

3–4 months or later

depending on recovery.

Some patients should avoid repeated:

Very-heavy, low-repetition bench pressing, particularly after a significant rupture.

Return to Contact Sport

Return to collision or contact sport generally requires:

Full motion

Near-symmetric strength

No pain

and often occurs around:

5–6 months or later.

Physical Therapy

Physical therapy is important once acute pain and swelling improve.

The goals include:

Restoring range of motion

Maintaining scapular mechanics

Progressively strengthening the shoulder

Returning safely to sport or work

Strength Progression

Resistance exercises should begin only when:

Motion is comfortable

and

The acute hematoma and inflammatory response have resolved.

Medication

NSAIDs may be used for:

Short-term pain and inflammation control, when appropriate.

Short-duration opioid medication may occasionally be required for:

Severe acute pain

or

Immediate postoperative pain.

Surgery

Surgical repair is generally favored for:

Complete tendon ruptures in young or active patients

especially when the tear is at or near the:

Humeral insertion.

Benefits of Surgical Repair

Operative repair generally provides better restoration of:

Strength

Preinjury activity level

Cosmetic contour

Patient satisfaction

than nonoperative treatment of complete tears.

Timing of Surgery

Repair is technically easier when performed:

Early after injury.

Delayed repair may be complicated by:

Retraction

Scar formation

Tendon shortening

However, good outcomes may still be achieved in many chronic cases.

Repair According to Tear Location

The surgical technique depends on:

Where the muscle-tendon unit has failed.

Musculotendinous Junction Tear

A repairable tear at the musculotendinous junction may require:

Direct suturing of the torn ends.

Tendon or Humeral Insertion Tear

Tendon avulsion from the humerus is typically repaired by reattaching the tendon to its anatomic footprint using:

Suture anchors

Cortical buttons

Transosseous tunnels

or other fixation techniques.

Chronic Retracted Tears

If the tendon cannot reach the humeral insertion without excessive tension, reconstruction may require:

Interposition grafting

or

Tendon augmentation.

Autograft or allograft tissue may be used depending on the defect.

Postoperative Immobilization

Following repair, the shoulder is usually protected in a:

Sling

with the arm maintained in:

Adduction

Internal rotation

and slight flexion.

Protection typically lasts approximately:

4–6 weeks.

Early Postoperative Motion

Pendulum or Codman exercises may begin early when permitted.

Excessive:

Abduction

and

External rotation

are avoided initially because they increase tension across the repair.

Six-Week Rehabilitation

Around 6 weeks, many protocols begin:

Gentle passive range of motion in multiple planes

together with:

Periscapular strengthening

Isometric exercises

Three-Month Rehabilitation

By approximately:

3 months

the goal is usually:

Near-full range of motion

with progression into:

Light resistance exercise.

Later Strengthening

Over the following several months, resistance is progressively increased.

Return to unrestricted activity may occur around:

6 months

provided adequate healing, motion, and strength have been restored.

Heavy Bench Pressing After Repair

Even after successful repair, repeated:

High-weight, low-repetition pectoralis loading

may be discouraged because it recreates the mechanism associated with rupture.

Follow-Up

The patient is generally reviewed approximately:

10–14 days after surgery

for:

Wound evaluation

Suture or staple removal when appropriate

Ongoing Follow-Up

During rehabilitation, periodic review assesses:

Range of motion

Strength

Pain

Repair integrity

Progression of activity

Follow-up intervals are individualized but may initially occur every:

Several weeks.

Prognosis

The overall prognosis is:

Good.

Most patients regain useful shoulder motion and strength.

Operative Prognosis

For complete tears in active patients, operative management generally provides the best chance of restoring:

Preinjury strength

Sports participation

Work capacity

Normal anterior axillary contour

Nonoperative Prognosis

Patients treated nonoperatively may function well in daily activities but commonly retain some reduction in:

Adduction

Internal rotation

Forward-flexion strength

and may have a persistent cosmetic defect.

Complications

Complications are uncommon but may include:

Re-rupture

Hematoma

Infection

Heterotopic ossification

Stiffness

Persistent weakness

Failure to return to previous activity level

Re-Rupture

Re-rupture may occur with:

Premature heavy loading

New trauma

Failure of fixation

Adherence to rehabilitation restrictions is important.

Persistent Weakness

Incomplete restoration of strength may result from:

Chronic tear

Muscle atrophy

Tendon elongation

Incomplete rehabilitation

Patient Monitoring

Patients should be monitored for:

Wound healing

Axillary contour

Range of motion

Adduction strength

Internal-rotation strength

Progressive return to activity

Key Principle

Pectoralis major tendon rupture most commonly occurs in young to middle-aged men during forceful eccentric loading, classically during the lowering phase of a heavy bench press.

The hallmark findings are:

Sudden pain, bruising, loss of the anterior axillary fold, palpable tendon discontinuity, and weakness of shoulder adduction and internal rotation.

Complete tears in active patients are generally best treated with:

Early anatomic surgical repair followed by protected, progressive rehabilitation.