Groin pain ranks among the most diagnostically challenging complaints in medicine because the region is an anatomical crossroads where muscles, tendons, joints, nerves, and organs all converge in a small space. A six-year review of nearly 900 cases in athletes found that hip joint problems alone accounted for about 56 percent of groin pain presentations, yet adductor injuries, hernias, spinal problems, and urological conditions can all produce nearly identical symptoms. The overlap is so significant that an international consensus panel had to create a standardized classification system just so clinicians could speak the same language when describing the problem.
Why This Region Is So Hard to Diagnose
The pubic bone sits at the center of an intense tug-of-war. Abdominal muscles pull upward on it while the thigh’s adductor muscles pull downward, and hip flexors add their own forces from the side. A review of the anatomy around the pubic symphysis found that chronic groin pain in athletes is frequently multifactorial, with multiple problems coexisting rather than a single clean diagnosis explaining everything. That alone makes the groin different from, say, a sore knee, where imaging often points to one structure at fault. Here, a torn labrum inside the hip joint can exist alongside a strained adductor tendon and irritated inguinal tissues, all feeding into the same aching sensation near the crease of the hip.
Adding to the difficulty, pain in the groin does not always originate there. The lumbar spine and sacroiliac joint can refer pain into the groin without any local tissue damage at all. Urological and gastrointestinal conditions can mimic musculoskeletal groin pain convincingly. Even problems at the knee in young patients sometimes trace back to a hip disorder that radiates downward rather than into the groin itself.
The Doha Classification System
For years, clinicians used a patchwork of overlapping and sometimes contradictory terms to describe groin pain. In 2014, an international expert group reached unanimous agreement on a standardized classification, now widely known as the Doha agreement. It divides groin pain in athletes into three broad categories: defined clinical entities (adductor-related, iliopsoas-related, inguinal-related, and pubic-related groin pain), hip-related groin pain, and a catch-all for other causes. The system is built around which structure reproduces pain on clinical examination rather than what imaging happens to show, because imaging findings in the groin are notoriously unreliable on their own.
Reliability testing of this classification found that agreement between examiners ranged from slight to substantial depending on the specific entity being diagnosed. Adductor-related pain, for instance, is easier to agree on because there is a straightforward clinical test for it, while inguinal-related and pubic-related categories generated less consistent agreement. This variability is worth knowing about, because it means a second opinion from a different clinician can sometimes reclassify a diagnosis, particularly for the less clear-cut categories.
Hip Joint Problems as the Leading Cause
In athletes presenting with groin pain, the hip joint itself is the single most common source. A review of 894 sporting cases over six years found that hip joint pathology was the leading clinical entity at roughly 56 percent, and it was significantly more likely to present in isolation than other causes. Within that group, femoroacetabular impingement accounted for about 40 percent, labral tears for 33 percent, and osteoarthritis for 24 percent. These numbers overlap somewhat because impingement and labral tears often coexist.
Labral tears deserve particular mention because they are easily missed early on. A study of patients with confirmed labral tears found that 92 percent reported groin pain as a primary symptom, and 86 percent rated their pain as moderate to severe. The pain typically worsens with activities that involve deep hip flexion or rotation, and many patients describe a catching or clicking sensation. However, groin pain from a labral tear can feel identical to pain from an adductor strain or even a sports hernia, which is why clinical testing and imaging are both needed to sort things out.
Hip osteoarthritis is another major player, particularly in older adults, though it can appear surprisingly early in people with longstanding impingement or prior hip injuries. Avascular necrosis of the femoral head, where the bone loses its blood supply and begins to collapse, also presents with progressive groin pain and is more common in people who use corticosteroids long-term, drink heavily, or have certain blood disorders. Both conditions tend to cause groin pain that is worse with weight-bearing and improves with rest, at least initially.
Adductor-Related Groin Pain
The adductor muscles, particularly adductor longus, are among the most frequently injured structures in sports that involve kicking, cutting, and rapid changes of direction. Adductor longus tendinopathy has been identified as the main cause of adductor-related groin pain, and it can lead to significant time away from sport, sometimes requiring surgery when conservative treatment fails. The diagnosis is made when a patient has chronic groin pain that worsens with resisted hip adduction, meaning squeezing the legs together against resistance.
One important wrinkle: imaging can show abnormalities in the adductor tendons of athletes who have no pain at all. Asymptomatic findings such as tendon thickening, calcifications, and small cortical erosions at the bone attachment are common in athletes. This means that seeing something on an MRI or ultrasound does not automatically explain a patient’s pain. The most specific imaging sign of true tendinopathy, rather than incidental wear and tear, is an intratendinous tear within the adductor longus itself.
The adductor squeeze test performed with the hips bent to 90 degrees is a commonly used bedside test. A prospective study of 382 patients found it was sensitive at about 85 percent for detecting pubic and adductor problems, but it was not very specific, meaning it often lights up positive even when the pain is coming from somewhere else. Clinicians therefore use it as a screening tool rather than a definitive answer.
Athletic Pubalgia and the So-Called Sports Hernia
Athletic pubalgia, sometimes called a sports hernia, is one of the most confusing diagnoses in this space because it is not actually a hernia in the traditional sense. There is no visible bulge and no bowel poking through a hole. Instead, the term refers to a disruption or weakening of the tissues where the abdominal wall meets the pubic bone. Because the pubis acts as a pivot point between the abdominal muscles above and the adductor tendons below, strain on either side of this junction can produce deep, aching groin pain that is worse with exertion.
MRI is the primary imaging tool here, and it can identify tears or strains of the rectus abdominis insertion or the adductor tendons at the pubic bone. But the imaging does not always match the symptoms, and the clinical picture often overlaps with adductor tendinopathy and pubic bone stress injuries. This overlap is one of the main reasons the Doha classification moved toward symptom-based categories rather than trying to pin a single anatomical diagnosis on every patient.
Osteitis Pubis
Osteitis pubis is an inflammatory condition of the pubic symphysis itself. Although it was first described in patients recovering from urological surgery, it also occurs in athletes who subject the pubic bone to repetitive stress. The condition causes lower abdominal and suprapubic pain that can radiate into the groin, and it often requires a lengthy recovery. Because it is relatively uncommon, many clinicians are unfamiliar with it and may attribute the symptoms to more common causes, delaying diagnosis.
Imaging typically shows bone marrow edema around the pubic symphysis on MRI, along with irregularity of the joint surfaces. The tricky part is that mild symphyseal changes are common in active people and do not always indicate disease. The clinical picture, including pain that is reproduced by pressing on the pubic bone and aggravated by activities like running or sit-ups, matters as much as the imaging findings.
Referred Pain From the Spine and Sacroiliac Joint
One of the most underappreciated causes of groin pain is referred pain from the lower back or sacroiliac joint. A study examining patients with sacroiliac joint dysfunction found that nearly half reported groin pain as part of their symptom pattern. Patients with lumbar spinal stenosis and lumbar disc herniation also reported groin pain, though at lower rates. A separate study that mapped pain referral zones after provocative injections into the sacroiliac joint found that about 14 percent of patients described groin pain during the procedure.
What makes this tricky is that the groin itself may be completely normal on examination. The hip moves freely, the adductors are strong and painless, and imaging of the pelvis shows nothing remarkable. Meanwhile, the patient has a disc bulge or sacroiliac dysfunction that is sending pain signals along shared nerve pathways into the groin. Clinicians who do not include a spinal and sacroiliac assessment in their workup for groin pain risk chasing a local diagnosis that does not exist.
Nerve Entrapment Syndromes
Several nerves pass through or near the groin on their way from the lumbar spine to the leg, and any of them can become trapped or irritated. Nerve entrapment syndromes of the lumbar plexus are a rare but important cause of groin pain, particularly in athletes. The ilioinguinal, iliohypogastric, genitofemoral, and obturator nerves are the usual suspects.
Nerve-related groin pain often has a distinctive character: burning, tingling, or shooting sensations rather than the dull ache typical of tendon or joint problems. It may worsen with specific positions that stretch or compress the nerve and can be accompanied by altered skin sensation in the inner thigh or genital area. Because these syndromes are uncommon, they tend to be diagnosed late, often after months of treatment aimed at tendons or joints that were never the real problem. A diagnostic nerve block, where a small amount of local anesthetic is injected around the suspected nerve, can confirm the diagnosis when the pain temporarily disappears.
Non-Musculoskeletal Causes
Not all groin pain comes from muscles, tendons, or joints. In males, testicular conditions such as epididymo-orchitis, testicular torsion, and inguinal hernias (the traditional kind, where abdominal contents push through the inguinal canal) are all potential causes. Testicular torsion in particular is a surgical emergency that requires rapid diagnosis. Kidney stones passing through the ureter can produce intense, radiating pain that hits the groin, and urinary tract infections occasionally cause referred discomfort in the area.
In females, ovarian cysts, endometriosis, and ectopic pregnancy can all present with groin pain. These gynecological causes sometimes create diagnostic confusion when a woman also happens to be physically active, because clinicians may focus on musculoskeletal explanations first.
Gastrointestinal conditions are rarer mimics but do exist. There are documented cases of acute appendicitis presenting as a groin abscess rather than classic right lower abdominal pain, which highlights how atypical presentations can lead clinicians down the wrong path if they are not thinking broadly. Inflammatory bowel disease, diverticulitis, and even colon pathology can occasionally refer pain to the groin region.
Groin Pain in Children and Adolescents
The differential diagnosis shifts meaningfully in younger patients. Slipped capital femoral epiphysis, where the growth plate at the top of the thigh bone shifts out of position, is a condition most commonly seen in adolescents. It requires immediate surgical referral because delays in treatment lead to worse outcomes. While about 80 percent of affected patients are overweight, thin children are not immune, particularly those with underlying hormonal conditions such as hypothyroidism.
One of the classic pitfalls in pediatric groin pain is that a slipped epiphysis often presents as knee or thigh pain rather than groin pain, leading clinicians to examine the wrong joint entirely. Guidelines recommend that any child or adolescent with open growth plates who presents with thigh or knee pain should have a hip examination as part of the evaluation. Plain X-rays, especially a frog-leg lateral view, are usually sufficient to make the diagnosis.
Other pediatric causes include Legg-Calvé-Perthes disease (avascular necrosis of the femoral head in children), septic arthritis of the hip, and apophysitis at the various muscle attachment points around the pelvis, which are vulnerable during growth spurts. Infections deserve special attention in children because septic hip can destroy the joint rapidly if untreated, and any child with groin or hip pain accompanied by fever and inability to bear weight needs urgent evaluation.
How Clinicians Sort Through the Possibilities
Given the sheer number of diagnoses that can cause groin pain, the clinical examination is the first and most important filter. Clinicians assess which movements reproduce the pain: does it hurt to squeeze the legs together (adductors)? To flex the hip against resistance (iliopsoas)? To rotate the hip inward (hip joint)? To cough or bear down (inguinal)? The pattern of provocation narrows the list dramatically before any imaging is ordered.
Imaging follows clinical suspicion. Plain X-rays are the starting point for hip joint pathology and bony abnormalities. Ultrasound is useful for soft-tissue structures like tendons and for detecting inguinal hernias dynamically. MRI provides the most detailed view and is the imaging modality of choice for labral tears, bone marrow edema, tendon injuries, and athletic pubalgia. CT scans are less commonly used in the groin but can be helpful for bony detail or when looking for abdominal pathology. Each modality provides different information depending on the suspected diagnosis, and clinicians choose based on what they are looking for rather than ordering everything at once.
Diagnostic injections play an underrated role. When a clinician suspects that hip joint pathology is causing the pain, an injection of local anesthetic directly into the hip joint can confirm or rule it out. A study of patients with labral tears involving early arthritis found that over 83 percent experienced some degree of pain relief after an intra-articular lidocaine injection, confirming the hip as the pain source. If the injection does not change the pain at all, the clinician knows to look elsewhere. The same principle applies to nerve blocks for suspected nerve entrapment and to sacroiliac joint injections for suspected referred pain.
Biomechanical Patterns That Predispose to Groin Pain
Research into how people move has revealed that groin pain is not always just about local tissue damage. A clinical commentary on adductor-related groin pain identified three distinct movement patterns among affected athletes. Roughly 40 percent showed a cluster involving excessive ankle eversion and knee internal rotation with higher knee loads. About 15 percent showed a pattern dominated by increased hip flexion, contralateral pelvic drop, and higher hip loads. The remaining 45 percent moved with increased ankle loading and prolonged ground contact time. These different biomechanical profiles suggest that the same diagnosis, adductor-related groin pain, can arrive through very different mechanical pathways depending on the individual.
This has practical implications for rehabilitation. A generic stretching and strengthening program may miss the mark if the underlying movement dysfunction is at the ankle or trunk rather than the hip. Clinicians increasingly use movement analysis as part of their assessment, looking not just at where the pain is but at how the whole kinetic chain is functioning during sport-specific tasks. The evidence is still evolving, but the direction is clear: groin pain treatment works better when it addresses the mechanical cause, which may be far from the groin itself.
When Multiple Diagnoses Coexist
Perhaps the most important take-home for anyone dealing with persistent groin pain is that more than one thing can be wrong at the same time. The anatomical review of the pubic region noted that the traditional approach of identifying a single discrete pathology does not always apply, because multiple pathologies frequently coexist. A patient might have a labral tear and an adductor strain and some sacroiliac dysfunction, with each contributing a portion of the overall pain experience.
This is why groin pain that does not respond to treatment for one assumed diagnosis should prompt reconsideration rather than more of the same. If physical therapy for an adductor strain is not helping after several weeks, it does not mean the therapy failed. It may mean the adductor was only part of the story, and a hip joint problem or referred spinal pain is contributing as well. Clinicians who approach groin pain as a puzzle with potentially multiple pieces tend to get better results than those who fixate on a single culprit from the start.
Red Flags That Demand Urgent Attention
Most groin pain is not dangerous, but a few presentations require immediate medical evaluation:
- Acute testicular pain: Testicular torsion can cause irreversible damage within hours and requires emergency surgery.
- Fever with hip or groin pain: In children especially, this combination raises concern for septic arthritis, which destroys cartilage rapidly if untreated.
- Inability to bear weight after trauma: Stress fractures of the femoral neck can progress to complete fractures if missed.
- Night pain and unintentional weight loss: These are classic warning signs for malignancy, which can present as groin or hip pain when tumors affect the pelvis or proximal femur.
- Sudden severe pain in a pregnant woman: Ectopic pregnancy is a life-threatening condition that can produce groin and lower abdominal pain.
These red-flag scenarios are uncommon, but they sit in the background of every groin pain evaluation. Clinicians screen for them first because the consequences of missing them are so much worse than the consequences of a delayed musculoskeletal diagnosis.