I Have Groin Pain.  What is it? Why does it happen? How does a Physiotherapist assess and diagnose it?

The Anatomy of the Groin and Associated Pain

The groin is a complex area with many interconnected structures, making diagnosis challenging. Groin pain often involves multiple structures, as the area contains a network of bones, muscles, tendons, fascia, and joints. There is also some ambiguity about the exact location of the groin. Generally, it’s where the lower abdomen meets the upper region of the legs, extending from the pelvis. The main musculoskeletal structures in this area include the hip adductors, hip flexors, abdominal muscles/tendons/enthesis, the pubic symphysis, the inguinal canal and lower limb nerves coming from the lumbar spine.

Groin pain typically occurs on the inner, upper thigh where the pubic bone meets the thigh, but it can also present centrally in the upper thigh. This pain can start suddenly or develop gradually. If an acute injury is not managed well, it can become chronic, leading to an overuse injury that takes much longer to heal. Chronic pain is defined as pain persisting for more than three months and can arise from both sudden and gradual injuries. Acute groin pain usually affects one side but can spread to nearby regions and become bilateral. Acute groin pain, caused by hip adductors or hip flexors, typically occurs when the muscle is stretched before or during a forceful contraction.

Chronic groin pain often begins with discomfort later during exercise or afterward, though there may be no pain during the activity itself. Following exercise, there may be either pain or increased stiffness. With proper warm-up, the pain may subside, creating a cycle typical of chronic groin issues. If activity continues without adequate rest and rehabilitation, the condition can progressively worsen, causing pain to appear earlier during exercise and followed by increased stiffness afterward.

Pubic Symphysis

The left and right sides of the pelvis meet at the front of the body through the pubic symphysis, a joint. The medial part of the pubis, where the left and right pelvic bones converge, is covered by a thin layer of hyaline cartilage attached to a fibrocartilaginous disc. The joint is supported by the superior pubic ligament above it and the inferior pubic ligament below. Many muscles and tendons attach to the pubic symphysis.

Hip Adductors

The hip adductors are a group of muscles that work to adduct the thigh bone (pulling it towards the body), flex the hip joint (raising the knee, especially when the hip is extended), and stabilize the hip joint. During walking or running, when the foot is planted, the hip adductors help stabilize the pelvis and assist with postural control alongside other muscles in the lumbopelvic region. Depending on hip positioning during movement, some adductors may aid slightly in hip extension or in internal and external rotation of the femur, with a greater role in internal rotation. Their contribution to hip flexion is not as prominent as that of the hip flexors. The hip adductor muscles include the pectineus, adductor brevis, adductor longus, adductor magnus, and gracilis. Among these, the adductor longus is most often injured in soccer due to the strain from acceleration, deceleration, lateral movements, and kicking. All hip adductors insert on the body of the pubic bone medially, with the exception of the pectineus, which inserts slightly more laterally. The adductor longus’ tendon fuses with the tendons of the rectus abdominis and external oblique. Hip adductor pain tends to present more medially in the upper thigh, where the pubic bone meets the thigh. Pain aggravated by kicking, lateral movements, and pivoting/turning is likely to involve the hip adductors.

Hip Flexors

As mentioned, the hip adductors have a role in hip flexion, as do other hip flexor muscles, including the rectus femoris (one of the four quadriceps muscles), sartorius, tensor fascia lata (TFL), and iliopsoas. The iliopsoas is the primary hip flexor, composed of two muscles from different origins that come together as one. The iliacus originates from the anterior surface of the ilium (the inner part of the pelvis), while the psoas originates from the vertebral bodies/discs/facet joints of T12-L5. Together, they attach to the femur. The iliopsoas is crucial for hip flexion, stabilising the hip and lumbar spine, and assisting with trunk flexion (e.g., sit-ups). The second major hip flexor, the rectus femoris, is also a powerful knee extensor as part of the quadriceps group. It plays a key role in kicking, where it stretches significantly in hip extension and knee flexion, as the leg is pulled back and the foot moves towards the bottom. Groin pain that is central in the upper thigh is more likely related to the hip flexors, especially if it is triggered by straight-line running. Acute injuries to the iliopsoas and rectus femoris are relatively common.

Inguinal Region

The inguinal canal is a passage in the anterior lower abdominal wall on both sides, allowing structures to pass from the abdomen to the lower extremity. Soft tissues in this area form an anterior wall, posterior wall, floor, and roof. The end of the inguinal canal, just above the pubic bone, is called the external (or superficial) inguinal ring, while the beginning is 4-6 cm laterally at the internal (or deep) inguinal ring. The inguinal ligament and lacunar ligament form the floor, while the transversalis fascia, internal oblique muscle, and transverse abdominis (two of the four core muscles) make up the roof. The transversalis fascia forms the posterior wall, and the aponeurosis of the external oblique and internal oblique forms the anterior wall. The inguinal ligament plays an important role in stabilizing the hip joint and lower abdomen, allowing for normal mobility and preventing hernias.

Common injuries in this area include sports hernias, inguinal hernias, and femoral hernias. A sports hernia involves a tear of any soft tissue structure in this lower abdominal region, though unlike a traditional hernia, it may not involve tissue pushing through the tear. An inguinal hernia occurs when abdominal tissue, such as a part of the intestines, pushes through an opening in the lower abdominal wall, causing a bulge. A femoral hernia, though less common, is a similar protrusion just below the inguinal canal. These injuries are often caused by repetitive stress on the lower abdominal muscles and ligaments, from actions such as coughing, straining, kicking, and heavy lifting. If groin pain is worsened by sit-ups or coughing, it is more likely related to the inguinal region.

Hip Joint

Issues with the hip joint’s bone, cartilage, synovium, labrum, or ligaments can all refer pain to the groin.

What other, less likely musculoskeletal causes could your groin pain be?

1. Somatic Referred Pain from the Lumbar Spine or Sacroiliac Joint

It is possible to experience groin pain without any issues in the groin or hip structures themselves; the pain may originate from the lumbar spine or sacroiliac joint (SIJ). Although less common than the four main causes discussed elsewhere and the hip joint, this is still a significant cause of groin pain. The SIJ can refer pain to the groin and the scrotal area, while the lumbar spine, especially levels L1-3, can refer pain to the groin area. Conditions such as osteoarthritis or inflammatory arthropathies in the lumbar spine joints, SIJ, hip, and pubic symphysis can also cause groin pain.

2. Nerve Entrapment

Entrapment of the obturator, ilioinguinal, genitofemoral, lateral cutaneous, or pudendal nerves can cause groin pain.

• Obturator nerve: This nerve may become trapped as it enters the adductor muscle compartment, leading to symptoms resembling a hip adductor issue. Pain may occur on hip abduction stretch, and there may be weakness in hip adduction. After exercise, numbness in the medial thigh and weakness in maximum hip adduction contraction can help distinguish this from other issues. Patients often report feeling weak and experiencing decreased propulsion when running.
• Ilioinguinal, genitofemoral, and lateral cutaneous nerves: These are sensory nerves, so if they are impinged, there will be no strength or control deficits, but pain or pins and needles may occur around the thigh, groin, and genital areas.
• Pudendal nerve: This nerve supplies motor control and sensation to the genitals and anus, which may be affected. Pain due to pudendal nerve entrapment is primarily felt while sitting.

3. Stress Fractures in Hip and Pelvic Bones

• Neck of the femur or acetabulum:  can result from overload in activity or sometimes from high-energy trauma. Pain is often insidious and diffuse, worsening with increased activity. MRI scans are more sensitive than X-rays for confirming stress fractures
• Pubic ramus: Stress fractures in this area are common in distance runners with high training loads, especially those with low initial aerobic fitness, poor nutrition, or low bone mineral density. There will be no pain on resisted hip adduction. Pain that worsens progressively with exercise may indicate a stress fracture or, in young athletes, an apophysitis.

4. Apophysitis or an Avulsion Fracture

An avulsion fracture occurs when a small piece of bone is pulled off by a tendon or ligament attachment. Where tendons insert in young kids whose bones have not completely developed yet, there’s a growth plate.  Kids can get apophysitis which is inflammation of the specific apophysis due to continual pulling of the tendon on the bone from overuse and or weakness of that muscle/tendon.  The main bony landmarks that an avulsion fracture or apophysitis can occur at and give you pain in the groin is anterior superior iliac spine, anterior inferior iliac spine and the pubic bone.

5. Active Trigger Point

A muscle may become hyper-irritable and refer pain to the groin, either to protect another structure or due to a muscle tear. This can happen in several muscles in the lumbopelvic region.

6. Non Musculoskeletal Causes of Groin Pain

If the pain is not following one of these many musculoskeletal conditions patterns subjectively and objectively, they are not from a musculoskeletal structure. Non-musculoskeletal causes of groin pain are intra-abdominal abnormalities, tumours, inguinal lymphadenopathy and gynaecological conditions.  Some of the main symptoms for these conditions are unintended weight loss, recent illness, increase in pain at night, or trouble sleeping or getting back to sleep at night, night sweats, fever, changes in bowel or bladder habits and fatigue.  However, some of these symptoms relating to pain could be musculoskeletal.  The physiotherapist will advise your GP on the findings of the examination if it’s found your pain is not musculoskeletal.  The GP will do their own assessments and provide treatment and/or refer you on to any specialists or for any scans as necessary.

Causes and Incidence of Groin Injuries

The incidence of groin injuries in soccer players is accounted for up to 19% of all injuries in men and up to 14% in women (1).  In adductor related injuries in elite male soccer players, re-injury rates are reported to be 15%, with rehabilitation time being almost double the second time, emphasising the importance of thorough and systematic rehab, including patience with return to sport (2). Another recent review found that other sports with a high incidence of groin injury were ice hockey and sports with repeated in game kicking, positions with more kicking involved.  All these studies are only going off results of groin injuries requiring time off, being a small percentage of all groin injuries.   A study on football players found that 49% had groin pain during their season, with 31% saying their groin pain lasted greater than 6 weeks (3).

A study of almost 1000 soccer players found that 49% of groin injuries are adductor related, 30% iliopsoas and 19% abdominal (4).  Another study looked at acute onset of groin pain and what the diagnosis of these injuries were, having adductors be 66%, iliopsoas up to 25% and rectus femoris up to 23% (5).  The mechanism of injury in groin pain in kicking sports was mainly kicking at 40% and in non-kicking sports was a quick change in direction.  Kicking sports were 76% of these injuries, with basketball being next at 10% (5).

Why Do Groin Injuries Occur?

Studies have found that those with hip and groin pain have pain and decrease strength through the hip adductors.  They also have reduced hip internal rotation range of motion, decreased trunk muscle motor control and strength but hip external rotation is within normal limits.  Besides these specific impairments, changes in training could have brought on the issue.  Whether it’s picking up a new activity, introducing a new exercise or the intensity or volume of your current training has changed.

Physiotherapy Assessment of Groin Injuries

A physiotherapy assessment for groin injuries is comprehensive and multi-faceted, focusing on understanding the patient’s pain and function to arrive at an accurate diagnosis and treatment plan.  The groin is a very busy area with lots of musculoskeletal structures and often more than one structure is injured.   Here’s a breakdown of the assessment process:

Subjective History

• Detailed Interview: The physiotherapist will gather a thorough medical and activity history, including:
  • Location and Type of Pain: Specific areas of pain and the characteristics (sharp, dull, aching).
  • Mechanism of Injury: How the injury occurred (e.g., trauma, overuse).
  • Onset and Progression: When the pain started, how it has changed over time.
  • Aggravating and Easing Factors: Activities that worsen or alleviate the pain.
  • 24-Hour Pain Pattern: Variation of pain throughout the day.
  • Work and Exercise History: Current and past physical activities, any changes in routine.
• Hypothesis Formation: Based on the information gathered, the physiotherapist will formulate hypotheses about potential conditions affecting the patient.  This will then guide the physical examination.

Physical Assessment

The physical examination of groin injuries involves a comprehensive assessment that includes functional evaluations, range of motion testing, strength assessments, lumbopelvic control evaluation, and palpation of relevant anatomical structures. Below is a detailed overview of each component of the examination.

1. Functional Assessment

Functional movements are observed to identify deviations from normal biomechanics. Key activities include:

• Walking and Running: Observing gait patterns can reveal compensations, possible tight and weak muscles
• Single Leg Standing: Evaluating balance and stability can indicate weaknesses or control issues.
• Squatting, Jumping and hoping: Analyzing these movements helps assess lower limb alignment and strength. (e.g being pelvic alignment during hopping can reveal excessive drop, which may indicate a weak gluteus medius and increase the risk of injury due to excessive internal rotation of the femur.

2. Active Range of Motion (AROM)

Active movements of the hip are assessed for tightness or pain. The movements tested include:

• Hip Flexion/Extension
• Hip Abduction/Adduction
• Hip Internal/External Rotation

AROM is compared bilaterally and against normative data for the patient’s age, sex, and sport. Tightness or pain during specific movements provides insight into potential muscle impairments.  Lumbar spine active range of motion is also assessed giving insight to lumbar joint and musculature impairments.

3. Passive Range of Motion (PROM)

Passive movements help identify joint or muscle issues:

• Hip Internal Rotation: A large reduction in internal rotation suggests a potential hip joint issue.  Smaller reductions can be indicative of hip adductor muscle injuries or pubic symphysis problems.
• Hip Abduction: Pain or reduced range in abduction is indicative of hip adductor injuries or pubic symphysis dysfunction.
• Hip Extension: Pain or limitation in extension may suggest hip flexor injuries.

4. Strength Tests

Strength testing is crucial for assessing the functionality of hip adductors, hip flexors, and abdominal muscles:

• Adductor Squeeze Test: This test evaluates the strength and progression of hip adductor muscles or pubic symphysis injuries. Greater strength with less pain indicates a better condition.
• Isometric and Dynamic Strength Testing: Handheld dynamometers may be used for isometric testing, while concentric and eccentric strength can be assessed using weights. Key points include:
  • Diagnosis: Pain and decreased strength in hip adductors and hip flexors indicate injurys to these muscles or their tendons
  • Eccentric Adductor to Abductor Ratio: Needs to be greater than 0.8 to reduce the risk of re-injury, with optimal ratios of 1.0 for hockey (eccentric) and soccer players (isometric).
  • Return to sport: Hip adductor and flexor strength should exceed 80% of the non-injured side for safe return to sport, with greater than 95% being optimal.

5. Strength Tests for Lower Abdominal and Inguinal Region Injuries

• Resisted Sit-Up Test: Pain and weakness in a resisted sit up is evidence towards an inguinal injury.  Sit ups will cause pain in sports hernias.  If a resisted sit up is done with a palpable bulge as well in the inguinal or femoral location, this is positive for these hernias.

6. Lumbopelvic Control Assessment

Lumbopelvic control is assessed through various functional movements and simpler exercises. Proper alignment of the pelvis and lumbar spine is crucial for minimizing strain on the kinetic chain, reducing the risk of re-injury and time to return to sport.

7. Palpation

The physiotherapist palpates relevant structures to assess sensitivity and identify possible injuries:

• Structures Assessed: Adductors, pubic symphysis, psoas, inguinal region, lumbar spine, and sacroiliac joint.
• Injury Indicators: Increased tenderness upon palpation of these structures may indicate injury.

Conclusion

In summary, assessing groin injuries requires a comprehensive approach due to the complexity of the area and the potential for multiple injuries. The physiotherapy assessment aims to identify the exact cause of pain and dysfunction, leading to an effective treatment plan for recovery and return to activity. Accurate diagnosis is critical for guiding rehabilitation and ensuring optimal recovery outcomes.

References:

Brukner, P. (2017) Brukner & Khan’s clinical sports medicine.  Chapter 32. Sydney: McGraw-Hill Education (Australia) Pty Ltd.

Waldén M, Hägglund M, Ekstrand J. The epidemiology of groin injury in senior football: a systematic review of prospective studies. Br J Sports Med 2015;49(12):792–7.

Werner J, Hägglund M, Waldén M et al. UEFA injury study: a prospective study of hip and groin injuries in professional football over seven consecutive seasons. Br J Sports Med 2009;43:1036–40.

Thorborg K, Rathleff MS, Petersen P et al. Prevalence and severity of hip and groin pain in sub-elite male football: a crosssectional cohort study of 695 players. Scand J Med Sci Sports. Published online 8 December 2015. doi:10.1111/sms.12623.

Hölmich P, Thorborg K, Dehlendorff C et al. Incidence and clinical presentation of groin injuries in sub-elite male soccer. Br J Sports Med 2014;48(16):1245–50.

Serner A, Tol JL, Jomaah N et al. Diagnosis of acute groin injuries: a prospective study of 110 athletes. Am J Sports Med 2015;43(8):1857–64.

Tyler TF, Nicholas SJ, Campbell RJ et al. The association of hip strength and flexibility with the incidence of adductor muscle strains in professional ice hockey players. Am J Sports Med 2001;29:124–8.

Thorborg K, Serner A, Petersen J et al. Hip adduction and abduction strength profiles in elite soccer players: implications for clinical evaluation of hip adductor muscle recovery after injury. Am J Sports Med 2011;39:121–6.