Introduction 

Thigh contusion- a bruise or pooling of blood- is an injury to the soft tissues and muscles in the leg. A contusion often develops from a direct hit to the thigh, making hip or knee movement difficult.¹ A contusion is caused when a hard blow hits the muscle with enough force to cause damage.²

Thigh contusions are common injuries in high-contact or extreme sports such as rugby and skateboarding. However, any direct hit to the thigh can cause a thigh contusion. Thigh contusions can vary from mild to moderate to severe.  Most contusions can heal quickly with home treatments; however, some require medical intervention. The different symptoms of thigh contusion include:¹

• Soreness 
• Pain with active range of motion (AROM) and passive range of motion (PROM)
• Limited range of motion²

It is essential for thigh contusions to be diagnosed early, as delayed treatment can lead to various complications. These complications, and ways to prevent them, are discussed further to ensure successful outcomes of the treatment of thigh contusion in patients.¹

Pathophysiology of high contusion

Thigh contusion is caused by direct trauma to the quadriceps muscles (quadriceps femoris), with the vastus intermedius muscle usually being the most affected. The pathophysiology of contusion involves the following:

• Direct trauma to the muscle  leads to the formation of myonecrosis (tissue damage) and hematoma (blood pooling) 
• Scar formation follows along with muscle regeneration
• Haemorrhage and swelling in the  front of the thigh occur due to small muscle fibre tears
• Myositis ossificans (bone tissue formation) can occur if bleeding is left untreated³

Complications of an untreated thigh contusion 

An untreated thigh contusion can result in various complications ranging from acute to chronic.

Acute complications include:

• Increased swelling and loss of motion
• Bruising of bones and swelling around the injury
• Sharp pain during activities like kicking, jumping and changing direction³

Severe complications include:

• Compartment syndrome 
  • A medical emergency that requires urgent surgery
  • Fluid buildup causes increased pressure around the muscle, restricting blood flow
  • Signs of compartment syndrome include severe pain in moving joints, numbness and poor blood flow
• Infection (haematoma infection or abscess formation)
  • Hematomas (blood pooling)  can develop due to direct injury 
  • They create a space filled with blood. Bacteria can enter a hematoma site through skin damage, leading to infection
  • The signs of haematoma infection include increased pain, redness, swelling and pus⁴
  • Abscesses or sepsis (systemic infection) can occur if left untreated⁵
• Myositis Ossificans
  • This is where bone forms in the injured muscle after a significant contusion
  • Symptoms include mild to severe, sustained pain and swelling
  • The abnormal bone formation can also lead to a reduction in flexibility
• Ischemia (lack of blood supply) could be potentially life-threatening⁶

Risk factors for complications

Certain risk factors can lead to complications, which include:

• The severity of the injury
  • The severity of the injury determines the likelihood of complications
• Delay in the treatment of the injury
  • Untreated thigh contusions are associated with an increased risk of developing severe complications
• Underlying health conditions such as coagulopathies (clotting disorders)
  • For example, compartment syndrome in the leg of patients with coagulopathy secondary to cirrhosis is challenging to manage⁷

Prevention of complications

Complications of thigh contusions can be prevented through the following ways:

• Early diagnosis and treatment ensure the prevention of complications
• RICE (rest, ice, compression and elevation) should be used to reduce inflammation 
• Immobilising the limb (keeping it in one place)
• Monitoring for any signs of complications

Home treatments such as RICE can be effective for short-term and moderate complications. However, for severe complications, medical intervention is necessary to prevent further complications.⁸

Case studies 

There is a case report of a 39-year-old man with thigh compartment syndrome. He sustained a thigh contusion while playing basketball. He continued to play and worked in the office for the following 2 days. Fifty-two hours after his injury, he had severe pain, increased swelling and numbness in the front of his thigh and knee after a long walk. Sixty hours after his injury, he presented with compartment syndrome, and surgery (lateral decompressive fasciotomy) of the thigh was performed. The wound was closed after 5 days, and he could return to playing basketball after 2 months. The treatment of compartment syndrome remains controversial, as some reports have suggested that nonoperative management has better outcomes. Compartment syndromes as a result of thigh contusions can lead to intramuscular bleeding, which can become worse with further activity. It is essential to monitor symptoms to prevent further complications.⁹

Conclusion

If left untreated, thigh contusions can lead to complications ranging from mild swelling and pain to severe complications like compartment syndrome and infection. Understanding the risk factors would help determine appropriate treatment. Early diagnosis and timely treatment are essential to prevent complications that could arise from injury and encourage ideal recovery.