What is a hip flexor strain?
Hip flexor strains result from tearing or overstretching the muscles or tendons located at the top of your thigh or pelvic region. These muscles allow you to flex at the hip and bend your knees. Hip flexor strains can significantly reduce your mobility and activity.
Given that the anatomy of the hip is complex, the cause of hip pain can be a singular type injury or a number of overlapping causes.[1]
What are the symptoms of a hip flexor strain?
The main symptom of a hip flexor strain is pain in the front of the hip. The pain is often sudden and intense and increases when you lift your thigh toward your chest. You may also feel muscle cramps or spasms at your hip or thigh and tenderness to the tough in the region.[2]
Causes of a hip flexor strain
Hip flexor strains often result when overused muscles become inflamed, weak, and painful. Athletes who run or jump are more prone to developing hip flexor strain. Other sports that result in hip flexor pain include cycling, dancing, martial arts, football, rugby, and soccer.
The function of the hip flexors
The main function of your hip flexors is to bring your knee up towards your chest. They also assist you in bending at the waist. The hip flexors consist of two main sets of muscles, which connect your thigh bone (femur) to your pelvis. These include:
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The rectus femoris, which is part of your quadriceps or thigh muscles
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The iliacus and psoas major muscles are together known as your iliopsoas.
A hip flexor strain is a tear in these muscles, ranging from a mild (grade I tear) to severe (a grade III tear):
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Grade I tear - Only a few muscle fibres are damaged from a minor tear.
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Grade II tear - A moderate amount of muscle fibres are damaged, resulting in some loss of function.
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Grade III tear - The muscle fibres are completely torn and the muscles are dysfunctional.
Diagnosing hip flexor strain
To diagnose hip flexor strain, your physiotherapist or doctor will require a detailed history of the pain and perform a physical exam. The exact nature and cause of the pain will have to be established. The physical exam requires exposing the hip joint and inspecting the hip for swelling and inflammation. The examiner will also move your hip in different directions to stress the ligaments, tendons, and cartilage to evaluate their integrity.
The physical examination may consist of several assessments, including:
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Gait (walking) analysis - Your doctor or physiotherapist will be able to detect changes in the movement of the hip during walking.
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Palpation - The examiner will palpate (or touch) your hip to assess whether different structures are sensitive.
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Strength - The examiner will assess your hip for weakness and whether muscular weakness or muscle imbalances are causing pain in your hip.
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Range of motion (ROM) - The ROM determines how far the hip can move. Special instruments may be used to measure if there are limitations in the movement of the hip, which will help direct the treatment.
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Special tests - These are manoeuvres performed around the hip that strain particular ligaments, tendons, and cartilage to help identify which structure is causing hip pain.
Sometimes further investigation is required, including X-rays, CT scans, ultrasound scans, Magnetic Resonance Imaging (MRI), and even blood tests.
Treating a hip flexor strain
Once the diagnosis has been confirmed, treatment can begin. Treatment often involves using medications or injections to alleviate the pain and physiotherapy.
Conservative treatment, such as physiotherapy, is always a good place to start with treating a hip flexor strain. Firstly it is important to rest the hip flexor muscles. This may include temporarily stopping sports that aggravate the pain.
Physiotherapy management for chronic knee pain aims to relieve pain and restore range of motion and strength. Common interventions for the treatment of chronic knee pain include:
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RICE - Rest, Ice, Compress, and Elevate the hip if it is very swollen and painful (although this is usually affected directly after an injury has occurred).
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Manual therapy - Mobilising the knee joint and releasing any tightness in the surrounding muscles.
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Strengthening - Particularly the quadriceps (or thigh), gluteal (buttock) muscles, and deep abdominal muscles to help stabilise the hip joint.
In severe cases, such as a grade III tear, where many muscle fibres are torn, surgery may be required to repair the ruptured muscle.
Outlook
The recovery period for a hip flexor strain depends on the severity of the injury. Mild strains take a few weeks to heal, while more severe strains may take a few months.
Some people are more prone to developing hip flexor strains than others. Athletes or those that participate in vigorous activities or sports can take precautions to prevent injury. Ensuring that the muscles are warm before taking part in sports is essential. Athletes should also perform stretching and strengthening exercises to increase the flexibility and stability of the hip.
