An injury to the hamstring muscle is a painful problem, frequent among athletes, especially those who sprint, or run and stop suddenly. The hamstring is not a single muscle, but three muscles located at the back of the thigh. A hamstring injury may involve a strain, which is a stretching or partial tearing of the muscle, or an avulsion injury, which is a complete tear of the muscle, pulling it away from the bone. Because hamstring injuries are usually the result of one of the muscles being stretched beyond capacity, such injuries are commonly referred to as “pulled hamstrings”.
Risk Factors for a Hamstring Injury
While a hamstring injury can happen to anyone, individuals are at greater risk of suffering such an injury if they:
- Participate in running, soccer, tennis, football, basketball or dance
- Have had a previous hamstring injury
- Are not flexible or have not stretched prior to exercise
- Have a muscle imbalance between the quadriceps and hamstrings
- Are adolescents in the midst of a growth spurt
Symptoms of a Hamstring Injury
Patients with a hamstring injury may experience any of all of the following symptoms, depending on the severity of the tear:
- Sudden pain during exercise
- Snapping or popping sensation
- Pain in back of thigh or lower buttock
- Tenderness and bruising at the site
- Weakness in the hip or knee
- Tingling sensation at the back of the thigh
Since the hamstring muscles make it possible to extend the leg straight behind the body and to bend the knee, pain during these movements may be a sign of a hamstring injury.
Diagnosis of a Hamstring Injury
To determine whether the hamstring has been injured and to what extent, the doctor will take a medical history and perform a physical examination of the area. With the patient lying face down, the doctor will look for any sign of tenderness, bruising or muscle spasm on the back of the thigh and will move the leg into different positions to try to pinpoint the region of the damage. If the patient has difficulty putting weight on the affected limb, further diagnostic testing will likely be required, first X-rays to rule out any possible fracture, and then an MRI scan or ultrasound to view the hamstring tear itself.
Hamstring Injury Treatment
Treatment for a hamstring injury depends on the severity of the damage, but many cases will heal with minimal care. Patients can relieve symptoms and facilitate the healing process through home remedies such as resting, applying ice and taking anti-inflammatory medications to diminish pain and swelling. Physical therapy is also typically very beneficial, as it works to gently stretch and strengthen the hamstring muscle. As the symptoms improve, gradually increasing exercise may prevent a recurrence of the injury. Generally, most patients can resume normal activities and sports participation in 4 to 6 weeks when the symptoms are gone.
If these conservative measures are not effective for a partial tear, an injection of either corticosteroids or platelet rich plasma may be recommended. These treatments can provide significant relief from pain and assist in the healing of damaged tissue. Severe hamstring injuries may require surgery to repair the torn muscle, especially in athletic patients, who may otherwise experience weakened muscles or other limitations in their ability to fully engage in the sports of their choice.
Arthroscopic Hamstring Repair
The three hamstring muscles, located behind the thigh, attach to leg bones, allowing the knee to bend. Strains to the hamstrings are common, especially during vigorous sports activities involving running and jumping. Such injuries, whether they involve just over-stretching or an actual tear, can be painful and debilitating. Partial tears sometimes respond well to conservative methods of treatment, including rest and splinting because, as scar tissue forms during healing, it forms a kind of bridge, reconnecting muscle to bone.
More severe or complete (avulsion) tears occur more rarely. However, when they do occur, the distance between muscle and bone is too great to be bridged by scarring, and surgical repair is required. Traditionally, hamstring repair surgery has been performed through open techniques that require large incisions and expose the surrounding region to potential complications. In recent times, hamstring repair can be successfully managed arthroscopically.
Advantages of Arthroscopic Hamstring Repair
Arthroscopy is a minimally invasive procedure that offers many benefits to the patient over traditional surgery. During an arthroscopic hamstring repair, the necessary equipment, all of which is miniaturized, is inserted through a small incision into the problem area. A thin fiberoptic light, a magnifying lens, a tiny camera, and small surgical tools allow the surgeon to examine the injury in detail and make repairs with precision.
Advantages of arthroscopic hamstring repair include:
- Smaller incisions
- Less bleeding during surgery
- Less scarring
- Faster recovery
- Reduced risk of infection
- Reduced risk of complications
- More comfortable rehabilitation
One of the most important benefits of arthroscopic hamstring repair is that, through magnification, the surgeon can more precisely visualize the sciatic nerve. Avoiding this nerve is crucial. In previous standard operations, the sciatic nerve was sometimes damaged, resulting in serious complications.
The Arthroscopic Hamstring Repair Procedure
Arthroscopic hamstring repair, though most often performed where there has been tendon avulsion and the tendon has pulled completely away from the bone, may also be performed to repair a tear within the muscle itself. Proximal tendon avulsion, or tears from the pelvis, are more common than distal tendon avulsions, where the tendon is torn from the shinbone. In order to repair a tendon avulsion, the surgeon has to pull the hamstring muscle back to its proper location and to remove any scar tissue. At this point, the surgeon will stitch or staple the tendon to the bone. If there is a tear within the muscle itself, it will be sewn together with stitches.
Recovery from Arthroscopic Hamstring Repair
The length of recovery depends on the particular type of hamstring repair performed, but in all cases the affected leg will not be weight-bearing for a number of weeks, during which the patient will need to use crutches and a knee brace. Immediately following surgery, rest and cold compression therapy are used to control pain and swelling and painkillers can be taken as needed. The cold compresses have the added benefit of reducing the tissue damage that could be caused by swelling and fluid leakage.
Whether a hamstring tear heals through conservative treatment or surgical intervention, the formation of scar tissue is part of the healing process. Because scar tissue lacks the elasticity of normal healthy tissue, however, the healed hamstring is weaker, less flexible and more prone to reinjury than it was before. Therefore, rehabilitation is a necessary part of successful recovery.
After approximately 6 weeks, the patient will begin rehabilitative treatment. Normally, this will include gentle stretches to improve flexibility and range of motion, with the gradual introduction of strengthening exercises. It is important that patients recovering form arthroscopic hamstring repair wait to resume sports activities until advised that it is safe to do so by their doctors.