Differential Diagnosis for Adductor Strain in Athletes
When evaluating an athlete with suspected adductor strain, you must systematically exclude serious pathology first, then differentiate between adductor-related groin pain and four other distinct clinical entities: iliopsoas-related, inguinal-related, pubic-related groin pain, and hip-related pain, as these conditions frequently coexist and require different management strategies. 1
Critical First Step: Exclude Serious Pathology
Before considering musculoskeletal differentials, rule out:
- Non-musculoskeletal conditions: tumors, infections
- Serious hip pathology: stress fractures, slipped capital femoral epiphysis (SCFE), Perthes' disease, osteoarthritis
- Competing musculoskeletal sources: lumbar spine pathology 1
Primary Differential Diagnoses
1. Other Groin Pain Clinical Entities (Most Common Overlap)
The Doha Agreement classification identifies four distinct groin pain patterns that must be differentiated from adductor strain 1:
- Iliopsoas-related groin pain: Pain with hip flexion activities, tenderness over iliopsoas insertion
- Inguinal-related groin pain/disruption: Involves abdominal tendinous and fascial tissues connecting to inguinal ligament and pubic tubercle; comprises 5-20% of groin problems in male athletes but rarely occurs in females 2. Often misnamed "sports hernia" though true hernias are rarely found
- Pubic-related groin pain: Pain localized to pubic symphysis region, particularly in adolescent athletes where apophysitis is commonly misdiagnosed 3
Key clinical caveat: These conditions frequently coexist with adductor-related pain, making isolated diagnosis challenging 1.
2. Hip-Related Pain (Critical to Distinguish)
Hip pathology is the most important differential as it requires fundamentally different management 1:
Three main hip conditions to consider:
Femoroacetabular impingement (FAI) syndrome: Motion-related disorder with triad of symptoms, clinical signs, and imaging findings (cam, pincer, or mixed morphology). Pain typically in groin but may radiate to back, buttock, or thigh 1
Acetabular dysplasia/hip instability: Misalignment between femoral head and acetabulum causing rim overload 1
Intra-articular pathology without distinct osseous morphology: Labral tears, chondral lesions, ligamentum teres tears 1
Diagnostic approach for hip-related pain:
- A negative flexion-adduction-internal rotation test helps rule out hip-related pain, though its clinical utility is limited 1
- Athletes with hip/groin pain demonstrate: pain and lower strength on adductor squeeze test, reduced hip internal rotation range of motion, and reduced bent knee fall out range 4
- MRI findings of bone edema and secondary cleft sign provide moderate evidence for hip pathology 4
Critical pitfall: Hip examination tests have good sensitivity but poor specificity, making them useful for screening but not definitive diagnosis 1. Clinical examination and diagnostic imaging have limited diagnostic utility; therefore, a comprehensive approach combining history, examination, and imaging is essential 1.
3. Adductor Tendinopathy (Chronic Presentation)
Distinguished from acute adductor strain by:
- Chronic groin pain rather than acute injury
- Pain/weakness during isometric hip adduction
- Confirmed by MRI showing tendinopathic changes 5
This represents a continuum from acute strain and may develop if acute injuries are treated improperly 6, 7.
Imaging Considerations
MRI is the key diagnostic tool for differentiating these conditions 3:
- Complete adductor tears occur in 21-25% of cases 8
- Provides superior soft tissue detail crucial for accurate diagnosis
- Common misinterpretation occurs particularly in adductor- and pubic-related groin pain 3
Risk Factors That Aid Differential Diagnosis
Athletes with previous acute groin injury, adductor weakness compared to uninjured side, any injury in previous season, and reduced rotational hip range of motion are at higher risk for acute adductor injury 8. These factors help distinguish true adductor pathology from other causes.
Clinical Decision Algorithm
- Exclude serious pathology (fractures, SCFE, infection, tumors)
- Assess for hip-related pain: Perform flexion-adduction-internal rotation test; evaluate hip internal rotation and bent knee fall out range of motion 1, 4
- Localize pain pattern: Determine if pain is adductor-related (medial thigh), iliopsoas-related (anterior hip/groin with flexion), inguinal-related (lower abdominal/inguinal region), or pubic-related (symphysis) 1
- Evaluate chronicity: Acute injury (<6 weeks) suggests strain; chronic pain (>6 weeks) suggests tendinopathy or athletic pubalgia 6, 5
- Obtain MRI when diagnosis unclear or to grade severity and guide treatment planning 8, 3