Demystifying Hip Flexor Pain

Hip flexor pain can be a common and debilitating issue that affects individuals of all ages and activity levels. Whether you're an athlete, a fitness enthusiast, or someone in an office-based occupation, understanding the anatomy, causes, differential diagnosis and treatment options for hip flexor pain is essential. In this article we explore these key aspects to help you gain a better understanding of hip flexor pain and why it occurs.

Hip Flexor Anatomy

When we discuss hip flexor pain and anatomy, it's important to understand that the anterior hip region is part of of a complex lumbo-pelvic, hip and groin region that may have various pain presentations, diagnosis and symptoms. When we assess a patient's hip flexor pain, we consider factors both above and below the joint as well as systemic factors to rule out/in certain pathologies. This includes assessment of:

Iliopsoas Muscle: The iliopsoas muscle consists of two primary components: the iliacus muscle and the psoas major muscle. Both muscles contribute to postural stability during functional tasks in standing and during trunk and hip flexion.

• liacus Muscle: Originating from the iliac fossa of the pelvis, the iliacus muscle inserts on the lesser trochanter of the femur (thighbone).
• Psoas Major Muscle: The psoas major muscle originates from the lumbar spine (T12/L1-L5) and also inserts on the lesser trochanter of the femur.

Rectus Femoris Muscle: The rectus femoris muscle is one of the quadriceps muscles located at the front of the thigh. It is a biarticular muscle, crossing both the knee and the hip joint, and is important for both hip flexion and knee extension.

Sartorius Muscle: The sartorius muscle is the longest muscle in the body, originating from the anterior superior iliac spine (ASIS) and inserting into the medial tibia as part of the Pes Anserine. It aids in hip flexion, abduction, and external rotation.

Tensor Fasciae Latae (TFL) Muscle: The TFL muscle is a small muscle located on the lateral side of the hip. It arises from the iliac crest and inserts into the iliotibial (IT) band. The TFL assists in hip flexion, abduction, and internal rotation.

Pectineus: The pectineus is a small muscle that arises from the pectineal line and inserts onto the oblique line extending down from the base of the less trochanter. It assists in hip flexion and adduction.

Hip Joint & Surrounding Ligaments: The hip joint is a ball-and-socket joint formed by the femoral head (ball) and the acetabulum of the pelvis (socket). Various ligaments, including capsular ligaments are also involved. It allows for various movements, including flexion, extension, abduction, adduction, internal rotation, and external rotation.

Hip Nerve Structures: Various nerves may also contribute to anterior hip pain, such as Iliohypogastric nerve, ilioinguinal nerve, genitofemoral nerve, inguinal nerve and other femoral branches.

Causes of Hip Flexor Pain

Now that you have a better understanding of hip flexor anatomy, what are the most common causes of hip flexor pain?

1. Muscle Strains: The hip flexor muscles, notably the rectus femoris, can be strained due to sudden actions such as sprinting and kicking.
   
2. Muscle Tightness & Posture: Postural factors such as prolonged sitting related to occupation may cause tightness through the anterior chain.
3. Overuse or Repetitive Stress: Engaging in activities that involve repetitive hip flexion, such as cycling or running, can lead to irritation and/or tendinopathies.
4. Trauma or Injury: Direct trauma or impact/contusion to the hip area, such as a fall or sports-related collision, can cause anterior hip pain.
5. Referral Pain: Pain may be referred from the lower back or from deeper structures within the hip, presenting like hip flexor pain however this may be secondary to an underlying cause.

Differential Diagnosis

Hip flexor pain can often be diagnosed as a primary source of pain, however it may be a secondary symptom to another pathology/injury. Further, it's not uncommon to have multiple structures involved with hip and groin pain.

Some of the differential diagnosis to consider include:

1. Hip Joint Pathology: Conditions such as hip osteoarthritis, labral tears, and/or femoroacetabular impingement (FAI) can cause similar symptoms to hip flexor pain.
2. Lumbar Spine Pathology: Nerve impingement/irritation or disc herniations in the lower back can refer pain to the hip flexor area, mimicking hip flexor pain.
3. Inguinal Related Groin Pain: In some cases, an inguinal hernia can cause pain in the groin area, resembling hip flexor pain.
4. Bone Stress Injuries: Bone stress injuries, such as pubic overload or neck of femur stress responses can refer pain to the surrounding hip flexors and adductor muscles.

Treatment Options

Treatment for hip flexor pain is varied and is dependent on the signs, symptoms and factors that cause pain along with potential pathology. Treatment options may involve the following:

Rest and Activity Modification: Initially, reducing or modifying activities that exacerbate hip flexor pain may be advised to reduce overloading of certain structures. Referral for further imaging or investigation may be indicated in certain cases.

Physical Therapy: A skilled physiotherapist can design a customised treatment plan consisting of stretching exercises, strengthening exercises, manual therapy techniques, and targeted rehabilitation to address muscle imbalances, improve flexibility, and enhance hip dynamic stability. Analysis of your biomechanics can also be useful to assess factors that may increase anterior hip loading and cause pain.

Closing Thoughts

The anatomy of the hip region is complex, with multiple muscles and structures contributing to hip flexor function and potential pain. By understanding the intricate interplay between these structures, we can better comprehend the causes and mechanisms behind hip flexor pain. Physiotherapy can help you understand the cause and provide a clear treatment plan to reduce your hip flexor pain.

Are you experiencing hip flexor pain? Book an appointment with our friendly physiotherapists at our Brisbane CBD clinic today!

By Stephen Valassakis BSc (Hons), MSc, APA