A 38-year-old man presents to the office with a history of severe left hamstring pain after sustaining an injury during a softball game 5 days ago. He was stretching for a catch at first base when his foot slipped, causing him to do a near full split. He collapsed to the ground after the injury and had difficulty ambulating afterward. On examination he has moderate tenderness over the mid portion of the left hamstring but is able to extend his hip and flex his knee against resistance. There is no palpable or visual defect of the hamstring muscle compared to the contralateral leg. He has moderate ecchymosis in the area as shown in the figures. Radiographs are obtained and demonstrate no evidence of fracture.
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The hamstring consists of three muscles: the medial and superficial semitendinosus, the deep medial semimembranosus, and the lateral biceps femoris. The biceps femoris is divided into two parts: the superficial long head and deep short head. The biceps femoris attaches proximally to the ischial tuberosity and distally to the head of the fibula. The semimembranosus originates from the ischial tuberosity and attaches to the medial condyle of the tibia. The semitendinosus originates from the ischial tuberosity and attaches to the medial aspect of the tibia at the same attachment sites as the sartorius and gracilis tendons. The area where these three tendons come together is called the pes anserinus or “goose foot.” The hamstring muscles cross the hip and knee joints and function to extend the thigh and flex the knee.
Hamstring injuries occur as a result of sudden hip flexion and knee extension. These injuries commonly occur in sprinting athletes and recreational “weekend warriors.” Any sport that requires rapid starts and stops may cause a hamstring tear. The hamstring can tear at any level, with the proximal myotendinous junction being the most common location. An acute proximal hamstring rupture may tear all three tendons off the ischial tuberosity. Pediatric patients may avulse the ischial tuberosity apophysis, which is often diagnosed by an acute displaced fracture on radiographic examination.
Symptoms of a hamstring tear include a sudden sharp pain and occasionally an audible “pop” when the injury occurs. Patients often have persistent pain and difficulty ambulating after the injury. Acute hamstring tears can be diagnosed by physical examination alone. Ecchymosis may develop several days to one week after the injury. Knee flexion and hip extension strength should be assessed. Patients may have no noticeable weakness with mild injuries. A palpable and visible defect may be present in complete retracted proximal tears of the myotendinous junction. Significant ecchymosis and pain on palpation proximally warrants additional work-up including an MRI to determine if there is displacement of the tear. Pain in the mid to distal hamstrings without deformity does not require further imaging in most cases as midsubtance tears are treated conservatively.
Radiographic examination may be required to rule out an associated bony avulsion, which can occur in the pediatric population. MRI is the imaging modality of choice in patients with significant pain proximally. MRI can differentiate complete vs partial tearing and helps measure the degree of myotendinous displacement.
Most hamstring injuries can be treated nonoperatively with 4 to 6 weeks of protected weight bearing as tolerated, physical therapy, and pain control. Patients are allowed to begin gradual return to athletic activities when the hamstring strength is at 90% of the contralateral side. Patients with severe proximal injuries should undergo MRI to determine tendon displacement as clinical assessment can be unreliable in judging tendon injury. MRI evaluation is particularly important in athletes who desire to return to sports as severity of injury seen on MRI can help predict expected length of rehabilitation. Acute proximal hamstring tears with >2 cm of retraction in two out of three tendons and any displacement of all three tendons together should be treated surgically. However, surgical decision making is largely based on the patient’s age and activity level and may vary among surgeons. Surgical treatment for acute displaced proximal hamstring tears has shown improved rates of return to preinjury levels of sports participation and increased hamstring strength compared with nonoperative treatment. Other indications for surgery include gluteal sciatica resulting from tendon displacement and failure of nonoperative treatment.
- Alzahrani MM, Aldebeyan S, Abduljabbar F, Martineau PA. Hamstring Injuries in athletes: diagnosis and treatment. JBJS Rev. 2015;3(6).
- Hughes M. Hamstring injuries. Available at: http://www.orthobullets.com/sports/3102/hamstring-injuries. Accessed on July 29, 2015.