Can a knee tendon rupture occur without a significant injury?

Knee Tendon Rupture Without Injury

Yes, knee tendon rupture can occur without significant injury, particularly in patients with predisposing systemic conditions or chronic tendon degeneration. 1

Pathophysiology of Non-Traumatic Tendon Ruptures

• Rupture of a healthy tendon is very rare; such injuries usually represent the end stage of a long process of chronic tendon degeneration and overuse 1
• Most spontaneous ruptures occur in tendons that have undergone degenerative changes, making them vulnerable to failure even with minimal force 2
• There is a common misconception that tendon injuries are primarily inflammatory; most chronic cases represent degenerative conditions (tendinosis/tendinopathy) rather than acute inflammation 2

Risk Factors for Spontaneous Tendon Rupture

• Systemic diseases: Chronic renal failure is a significant risk factor for spontaneous tendon ruptures 3
• Medications: Certain medications, particularly corticosteroids, can weaken tendon structure 1
• Age: Increasing age leads to degenerative changes in tendons, making them more susceptible to rupture 1
• Repetitive microtrauma: Chronic overuse without adequate recovery time 1
• Genetic predisposition: Some individuals may have inherent tendon weakness 1

Common Sites for Knee Tendon Ruptures

• Patellar tendon: Connects the patella to the tibial tuberosity 1
• Quadriceps tendon: Connects the quadriceps muscle to the patella 1
• Both can rupture simultaneously in patients with predisposing conditions 3

Diagnostic Approach

• Clinical examination: Palpation for tendon gaps and specific tests like the Thompson/Simonds squeeze test (for Achilles tendon) are essential 2
• Imaging:
  • MRI is highly accurate for diagnosing tendon ruptures, with 86.4% accuracy for complete tears 2
  • Ultrasound can be considered as an alternative with slightly lower accuracy 2
  • Plain radiographs may show indirect signs such as patella alta (high-riding patella) in patellar tendon ruptures 1

Treatment Considerations

• Timing is critical: Delay in surgical repair beyond 3 weeks results in significantly poorer outcomes 1
• Surgical options:
  • Acute ruptures: Direct repair with longitudinal transpatellar drill holes 1
  • Chronic ruptures: Tendon augmentation with auto- or allograft should be considered 1, 4
• Rehabilitation:
  • Protected weight bearing and limited passive mobilization for approximately 6 weeks 1
  • Gradual return to activities based on tendon healing biology 1

Special Considerations

• Bilateral simultaneous tendon ruptures are rare but have been reported, especially in patients with systemic conditions 3, 5
• In patients with chronic renal failure, even minor trauma can lead to tendon rupture 3
• Neglected cases may lead to severe functional limitations including knee ankylosis, requiring more complex reconstruction 4

Preventive Measures

• Regular monitoring of tendon health in patients with predisposing conditions 2
• Appropriate activity modification in patients with tendinopathy symptoms 2
• Eccentric strengthening exercises may help prevent progression of tendinopathy to rupture 2

Remember that early diagnosis and appropriate treatment are crucial for optimal outcomes in patients with knee tendon ruptures, whether traumatic or atraumatic in origin 1.