Anatomy of the Hamstring Muscles
The hamstrings are a group of three thigh muscles that extend from the pelvis to the knee joint. They include the:
- Bicep femoris
These muscles help in extending your leg and bending your knee. Therefore, any damage to the hamstring muscle group affects both hip and knee movements.
Hamstring injuries are common sports injuries. Injury to the hamstring muscles or tendons may occur in the following ways:
Musculotendinous junction injury: A tear at the junction where the muscle joins the tendon.
Tearing of the muscle: Tearing of the belly of the muscle may take place.
Proximal hamstring injury: Separation of the proximal hamstring tendons from the bone.
Causes of Hamstring Injury
Hamstring injuries primarily occur when the muscle is exposed to extreme strain; when it is stretched beyond its ability or when it must withstand a sudden load. This is commonly seen while sprinting – the hamstring muscles must bear the body’s entire weight and experience extreme contraction as you push off the ground to move forward.
The factors that may increase your risk of hamstring injuries may include:
- Tight muscles due to lack of stretching exercises may cause injury.
- Imbalance in the strengths of the different muscle groups (contracting and expanding) in your leg for the same movement.
- Muscle fatigue, which lowers the ability of the muscles to absorb energy.
- Activities such as dancing which requires different movements may cause injury.
- Sports activities such as sprinting, basketball, football, and soccer.
- Incomplete healing of a previous injury to the hamstring muscle group.
- Adolescent athletes are more prone to injury as their bones grow faster than muscles.
Symptoms of Proximal Hamstring Injuries
The symptoms of proximal hamstring injury include:
- Sudden sharp pain behind your thigh during activity
- A pop sound following injury
- Swelling and tenderness of the affected area
- Discolouration or bruising behind your leg, just below the knee
Diagnosis of Proximal Hamstring Injury
When you visit the clinic for pain in your thigh region, your doctor will review your medical history and perform a thorough physical examination of your leg. In addition, imaging tests such as X-rays and magnetic resonance imaging (MRI) are ordered to identify and confirm the injury to the proximal hamstring.
Proximal Hamstring Repair
Proximal hamstring injuries can usually be treated with non-surgical options such as the RICE protocol, immobilization, and physical therapy.
However, avulsion injuries and complete muscle tears require surgery to repair the torn tissue. Proximal hamstring repair may involve the following steps:
- You are administered general anaesthesia and made to lie on your stomach.
- An incision is made (about 8cm) along the pelvic bone to expose the hamstring tendons.
- The sciatic nerve, which extends from the buttocks towards the thigh region, is identified and dissected from surrounding tissue.
- Any scar tissue is removed.
- The torn proximal hamstring tendon is pulled back into place and secured to the bone with the help of sutures or staples.
- Your doctor examines the integrity of your muscles with the bone and closes the incision.
- Your leg will be placed in a brace and you will be encouraged to keep weight off your leg.
- You are not allowed to lift heavy objects or perform any activity that may stress your hamstring muscles for about 2 to 3 weeks.
- Physical therapy exercises will be taught to enhance your flexibility, range of motion and strength.
- You can swim after 2 to 3 weeks and cycle after a month.
- Weight lifting exercises are allowed only after two months.
It may take you about 6 months for complete recovery. Your doctor will let you know when you can return to your sport.