The patients suffering from the biceps femoris tendon rupture may complain of sharp pain at the back of the knee following hyperextension of the affected knee. They may feel a pop on the affected knee during knee extension. Most of the victims had an injury while performing activities such as soccer, running, or water skiing. The injury usually renders the patient unable to walk.

The clinician may palpate a gap next to the ruptured biceps tendon. Sometimes, the examiner can also palpate a subcutaneous hematoma. Tenderness over the posterolateral aspect of the affected knee is common. The flexion force of the affected knee may decrease in severe cases.[8]

Imaging modality can assist in defining the extent and severity of the biceps femoris tendon injury. Plain films can be used to check the presence of avulsion injury, in which an avulsed bony fragment may be apparent.

However, in adults, the avulsed osseous fragment is not easily seen. In contrast, due to incomplete ossification, a detached bony chip is easier to find on adolescents.  

Magnetic resonance imaging can be used to assess the degree of the tendon retraction and integrity of the surrounding bony structure. Ultrasonography offers the advantage of zero radiation and is relatively inexpensive. Besides, sonography allows a dynamic assessment, which can be employed to assess the reciprocal movement the biceps femoris tendon against the surrounding soft tissues (Figure 1). Color or power Doppler ultrasound can be used to assess intra-tendinous/muscular hypervascularity, which is indicative of neovascularization or inflammation of the injured tendon. Comparison with the contralateral side may be valuable for diagnosis.[1]

Isolated rupture of the biceps femoris tendon typically receives non-operative therapy. Cohen (2007) indicated that in the patients with biceps femoris tendon rupture with tendon retraction less than 2cm, most athletes can return to high-intensity sport (e.g., professional football) approximately six weeks after injury. The ruptured tendon gradually heals, allowing the affected knee return to full strength. The non-operative treatment includes rest, ice, non-steroid anti-inflammatory drugs, gentle stretching and therapeutic exercise for 4 to 6 weeks.[9]

An acute biceps femoris tendon rupture may be associated with the injury of the semitendinosus and semimembranosus muscles. If there is a significant tendon retraction (> 5 cm), a surgical repair is usually needed.

Surgical repair of the ruptured biceps femoris tendon includes transverse incision over the gluteal crease, exposing the ruptured tendon, protection of the sciatic nerve, mobilization of the ruptured tendon and then reattaching it to the ischial tuberosity.

Most cases recover well after a non-operative treatment or a timely repair. But no specific guidelines address when should be treated surgically. Several case studies suggest that a complete biceps femoris tendon rupture should undergo surgical treatment.[10]

The differential diagnosis includes:

• Ischial tuberosity disease
• Hamstring enthesopathy
• Referred pain from the sacroiliac joints, lumbar spine,  pubic symphysis, gluteal muscles
• Sciatica
• Stress fractures of the pelvis or the fibular neck

Clinicians should be mindful that not all posterior thigh pain derives from the biceps femoris tendon injury. Besides, the biceps femoris tendon injury often occurs with an injury of the entire hamstring complex.[1]

The prognosis of the biceps femoris tendon injury is good if the injury receives prompt and appropriate diagnosis and treatment. Most athletes return to professional sports after treatment.[11]

Although complete rupture of the proximal biceps femoris tendon is not common, the patients may have weakness, pain and sciatic neuralgia if the injured tendon does not receive proper treatment.[1][11]

The education should be given to the public as more and more people participate in high-intensity exercises. The health-care providers should offer the best practice according to evidence-based medicine.

An interprofessional approach for biceps femoris tendon rupture is recommended. Biceps femoris tendon rupture is relatively common among young athletes and the physically-active population. Many patients visit the emergency department or the primary care provider once they have an injury. Hence, these professionals need to know about the diagnosis and management about the disorder. The key to prevent these injuries is education about the importance of warmup and stretching before exercise. For most patients, the prognosis is good. The non-operative treatment usually provides optimal symptom relief and functional recovery. The indication for surgical intervention remains uncertain.