From the Guidelines
The indirect head of the rectus femoris is most likely to be injured through activities that involve forceful hip extension combined with knee flexion, such as kicking or sudden changes in direction, which can cause strain on the tendon where it attaches to the anterior inferior iliac spine (AIIS) 1.
Mechanism of Injury
The injury commonly occurs during the eccentric phase of muscle contraction when the muscle is lengthening under tension. This can happen in various sports, particularly those that involve kicking, sprinting, or quick changes in direction. The study on tracing horseback riding and transport in the human skeleton 1 provides insight into the biomechanical stressors associated with different transport strategies, which can be applied to understanding the mechanisms of injury in various physical activities.
Presentation and Treatment
The injury presents as sharp pain in the front of the hip or groin, often accompanied by swelling and bruising. Treatment typically involves rest, ice, compression, and elevation (RICE protocol) initially, followed by gradual rehabilitation exercises to restore strength and flexibility. Non-steroidal anti-inflammatory drugs like ibuprofen may help manage pain and inflammation. Recovery time varies depending on the severity of the injury.
Prevention Strategies
Prevention strategies include proper warm-up routines, gradual training progression, and specific strengthening exercises for the hip flexors and quadriceps. Understanding the biomechanical stressors associated with different activities, as outlined in the study 1, can help in developing targeted prevention strategies to reduce the risk of injury to the indirect head of the rectus femoris.
Key Considerations
- The rectus femoris crosses both the hip and knee joints, making it susceptible to strain when both joints move simultaneously in opposing directions.
- Activities that involve forceful hip extension combined with knee flexion increase the risk of injury to the indirect head of the rectus femoris.
- Proper training, warm-up routines, and strengthening exercises can help prevent such injuries.
From the Research
Mechanism of Injury
- The indirect head of the rectus femoris can be injured through various mechanisms, including kicking or sprinting, as reported in a study on intrasubstance strain injuries of the rectus femoris muscle 2.
- Another study on a professional soccer player with an acute-on-chronic rectus femoris injury noted that the player continued playing and training after initial symptoms, which may have exacerbated the injury 3.
Anatomy and Injury Location
- The indirect head of the rectus femoris tendon has a specific anatomy, with a mean footprint length of 38.1 mm and a mean length of the tendon suitable for grafting of 46.1 mm, as described in a cadaveric study 4.
- Injuries to the indirect head of the rectus femoris can occur at the muscle-tendon junction, with a study noting that the deep tendon of the muscle's indirect head and those muscle fibers originating from this tendon can be affected 2.
Surgical and Rehabilitation Considerations
- Surgical findings in cases of indirect head of the rectus femoris injuries may include a mass of fibrous scar and fatty tissue encasing the deep tendon, which can be removed to promote healing 2.
- Rehabilitation protocols for indirect head of the rectus femoris injuries may involve a combination of physiotherapy sessions, including exercises such as pulley exercises, leg extension, and squatting, as well as a gradual increase in loading and running program 3.
- The use of platelet-rich plasma (PRP) injections has been explored as a treatment option for muscle injuries, including those affecting the rectus femoris, with some studies reporting positive outcomes 5, 3.