To the best of our knowledge, insertional tendinopathy (enthesopathy) of the distal biceps femoris tendon insertion has not been described in the literature. We present a patient with this condition who experienced pain in the posterolateral part of the knee. After an unsuccessful course of physical therapy, surgical debridement of the degenerative tendon led to complete resolution of the symptoms and a return to full sporting activities. The patient was informed that data concerning his case would be submitted for publication, and he provided consent. A thirty-four-year-old man presented to our clinic with two months of posterolateral right knee pain. The pain had started abruptly after a full day of playing in the surf at the beach. The pain was localized to the posterolateral part of the knee and worsened with deep knee flexion. There were no mechanical symptoms or instability on knee examination, and there was no effusion. Several courses of anti-inflammatory medication did not relieve the pain. ### Medical History The medical history included hypertension, dyslipidemia, and intermittent low back pain. The only prior surgery was an inguinal hernia repair. The musculoskeletal history included a diagnosis of iliotibial band tightness, which had been treated with stretching exercises at home. Three years earlier, he had sustained a torsional injury to the right knee while skiing. A magnetic resonance imaging (MRI) study at that time showed minor lateral meniscal fraying, but no substantial intra-articular pathology. He had been treated with a course of anti-inflammatory medications and physical therapy and had completely recovered. ### Physical Examination The patient was 175 cm tall and weighed 73 kg, with a body mass index of 23.8. The right knee had full active and passive knee motion from 5° of hyperextension to 135° of flexion. There was no knee effusion. The results of Lachman, anterior drawer, and posterior drawer tests were …