Background and Etiology
The knee is the largest joint in the body. It is built for weight bearing, stability and mobility. A tendon is the cord-like part of the muscle that attaches the muscle to the bone. it helps provide stability and mobility to a joint. The most common injury or condition of the knee is knee tendinitis, but more severe tendon injuries can occur. There are several groups of tendons that attach near and control the knee, including the hamstring tendons.
Hamstring Tendon Tear
The hamstring muscles are located along the back of the thigh. Most hamstring tears occur along the thick part of the muscles, or where the tendons insert at the pelvis. The hamstring tendons attach the hamstring muscles to the knee joint by attaching at the tibia (shin bone) and fibula at the knee joint and proximally at the pelvis.
The function of the hamstrings is to decelerate the lower leg as it moves forward during walking and running. The hamstrings also play a role in knee flexion. Hamstring tears can vary in severity, and are often caused by stretching the hamstring muscles too far.
Common causes of a hamstring tendon tear include:
- An injury to the back of the knee or a direct blow to the tendon
- Sudden change in acceleration or explosive activity in sports such as in football, track and field, or hockey.
- A hamstring tear can occur as a result of a fall where an individual lands awkwardly or directly on the knee.
- Laceration of the tendon
- Weakness or fatigue of the hamstring muscles in people where hamstring tendinitis places increased stress on the hamstring tendon.
- Immediate pain at time of injury
- A loud audible pop at the time of injury
- Swelling and bruising or ecchymosis is present in the back of the knee.
- There is a gap where the tendon has ruptured
- It is difficult to put weight on the leg
- Inability to straighten the knee due to pain
- It becomes difficult to actively bend the knee
Early diagnosis and treatment is the key to a successful outcome for a hamstring tendon tear. If diagnosis or treatment is delayed the integrity of the healing tissue can be compromised as a result of scarring and decreased blood flow. Most hamstring tears do well with conservative treatment including RICE and physical therapy. Surgical repair is used in cases of complete rupture of the muscle or tendon. Following surgery, structured and aggressive physical therapy is the treatment of choice for complete ruptures of the tendon. In the case of smaller tendon tears, conservative treatment without surgery may be recommended.
Avoiding the activities that produce the pain or stress the involved tendon is the first line of treatment.
- RICE: Rest, Ice, Compression Elevation should be used to reduce the stress on the bursa.
- NSAIDS (Non steroidal anti-inflammatory drugs) to reduce pain and inflammation.
- Injection of steroids may be indicated to reduce inflammation of the involved tendon
- Immobilization of the knee for 3-6 weeks to rest and promote healing. Individual will be placed in an immobilizer or brace and will move around with crutches to keep weight off of the leg.
- Physical Therapy: following the period of immobilization your physician will decide when you are ready for physical therapy. Treatment will emphasize gradual weaning off the immobilizing device, increasing weight bearing, restoration of knee range of motion and strengthening of the hamstring. It is important that the physician and therapist communicate during the early stages and progress your recovery program based on the principles of healing so as not to compromise the hamstring tendon.
- The patient will be progressed to more functional activities as normal knee range of motion and strength is restored.
- In severe recurrent conditions surgery to repair a torn or frayed tendon may be indicated.
Common Physical Therapy interventions in the treatment of Hamstring Tendon Tears include:
- Manual Therapeutic Technique (MTT): hands on care including soft tissue massage, stretching and joint mobilization of the knee and patella by a physical therapist to improve joint mobility and range of motion of the knee. Use of mobilization techniques also helps to modulate pain.
- Therapeutic Exercises (TE) including stretching and strengthening exercises to regain range of motion and strengthen the hamstrings and muscles of the knee and lower extremity.
- Neuromuscular Reeducation (NMR) to restore stability, retrain the lower extremity and improve movement techniques and mechanics (for example, running, kneeling, squatting and jumping) of the involved lower extremity to reduce stress on the tendons in daily activities. Taping, strapping or bracing may be indicated to rest the tendon and promote healing.
- Modalities including the use of ultrasound, electrical stimulation, ice, cold, laser and others to decrease pain and inflammation of the involved tendon and bursa.
Prognosis
If repair and treatment are initiated immediately, individuals with a hamstring tendon tear generally do well. Delay can result in the formation of scar tissue and retraction of the tendons. There is no guarantee that a completely torn hamstring can ever be rehabilitated to 100% strength and efficiency.
