The quadriceps muscle consists of a group of 4 muscles: the rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius. The rectus femoris arises from 2 heads, a direct head that attaches to the anterior inferior iliac spine and a reflected head that attaches just above the acetabulum. The rectus femoris inserts at the patella and acts to flex the thigh and extend the knee. The vastus lateralis, vastus intermedius, and vastus medialis attach at the proximal femur, insert at the patella, and act to extend the knee.
The myotendinous junction of the rectus femoris is the most common site of quadriceps injury. The injury is more often a strain rather than a tear. Because the rectus femoris crosses both the hip and the knee joints, it is thought to be more prone to injury. One of the most common mechanisms of injury is a kicking motion when the hip is hyperextended and the knee is flexed, causing combined loads of stretch and eccentric activation of the quadriceps muscle. Avulsion of the rectus femoris can also occur but is rare in skeletally mature athletes. Anterior inferior iliac spine physeal avulsion fractures are commonly seen in the adolescent and pediatric populations, but in adults, rectus femoris avulsions occur more often in high-level athletes such as professional football and soccer players.1
A discrete soft tissue mass on the anterior thigh may be seen in those with rectus femoris tears.1 On physical examination, flexing the knee with the hip in extension reproduces the pain by stretching the rectus femoris muscle (Ely’s test). Radiographs of the femur and pelvis are often obtained after the injury but are usually negative. Magnetic resonance imaging is the study of choice to confirm the diagnosis of rectus femoris tear.1
Rectus femoris tears are generally treated conservatively with rest, nonsteroidal anti-inflammatory drugs, and rehabilitation. A short period of protected weight bearing with crutches, usually 1 to 2 weeks, may be necessary before formal physical therapy is initiated. Return to sports varies based on patient symptoms but generally is possible 6 to 12 weeks after the injury. Minimally displaced tears will likely heal with a fibrous union and patients can return to competitive sports with minimal to no pain once healed. Surgical intervention may be considered if there is prolonged weakness and functional limitation.2,3
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).
Temple HT, Kuklo TR, Sweet DE, Gibbons CL, Murphey, MD. Rectus femoris muscle tear appearing as a pseudotumor. Am J Sports Med. 1998;26:544-548.
Adler KL, Cook P, Giordano BD. Rehabilitation following proximal rectus femoris repair: a case report. Int J Athletic Ther Training. 2015;20:25-30.
Gamradt SC, Brophy RH, Barnes R, Warren RF, Byrd TW, Kelly BT. Nonoperative treatment for proximal avulsion of the rectus femoris in professional American football. Am J Sports Med. 2009;37:1370-1374.