Classification
- Grade 1 strain is microscopic fibre disruption with no loss of strength.
- Grade 2 strain is a partial tear with weakness.
- Grade 3 strain is complete rupture with loss of function and a palpable defect.
- Tietjen classification of pectoralis major tears grades contusion or sprain, partial tear and complete tear, then subdivides by site.
Aetiology
- Eccentric contraction injures the myotendinous junction.
- Risk factors include fluoroquinolones, corticosteroids, anabolic steroids and previous injury.
Anatomy
- Hamstring strains most often involve the biceps femoris long head. Proximal avulsion arises from the ischial tuberosity.
- Rectus femoris avulses from the anterior inferior iliac spine in kicking, and from the apophysis in adolescents.
- Pectoralis major ruptures at the humeral insertion during bench press, most often the sternocostal head.
- Quadriceps tendon rupture occurs in patients over 40 at the superior pole of the patella.
- Gastrocnemius medial head tears at the musculotendinous junction, known as tennis leg.
Clinical Features
- Sudden pain with a pop, bruising and a palpable defect.
- Pectoralis major rupture loses the anterior axillary fold and gives bruising of the arm and chest.
- Quadriceps rupture gives an extensor lag, suprapatellar gap and patella baja.
- Gastrocnemius tear mimics deep vein thrombosis and needs ultrasound.
Investigations
- MRI shows fluid signal on T2 and defines retraction, grade and tendon versus muscle belly site.
Management
- Grade 1 and 2 strains are managed nonoperatively with early mobilisation and progressive loading.
- Proximal hamstring avulsion with two tendons torn and retraction over 2 cm favours surgery, though evidence is weak.
- Acute repair within four weeks gives better results than chronic repair. Chronic cases may need reconstruction with allograft.
- Complete pectoralis major tendon avulsion in active patients is repaired early, with better strength than nonoperative care.
- Muscle belly pectoralis tears and low demand patients are treated nonoperatively.
- Quadriceps tendon rupture is repaired by transosseous sutures or anchors.
- Gastrocnemius tears are treated nonoperatively.
Complications
- Myositis ossificans follows quadriceps contusion. Excision is delayed until the bone matures.
- Compartment syndrome follows thigh or calf haematoma.
- Sciatic nerve injury or tethering follows hamstring avulsion.
- Persistent weakness follows nonoperative management of complete tears.
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 12 October 2026.