Introduction

Hip flexor strains and tears are common injuries among athletes and active individuals, particularly in sports requiring explosive hip flexion, sprinting, and rapid directional changes.

The hip flexor muscle group primarily includes the iliopsoas (psoas major and iliacus), rectus femoris (part of the quadriceps), and sartorius muscles. Due to their role in hip flexion and stabilization during dynamic activities, these muscles are vulnerable to acute and overuse injuries.

An in-depth understanding of the mechanisms, classification, clinical presentation, and evidence-based management strategies is essential for physiotherapists to effectively diagnose, treat, and rehabilitate patients presenting with hip flexor strains.

Definition

• Hip flexor strains/tears refer to the partial or complete disruption of muscle fibers or tendinous tissues in muscles responsible for hip flexion, predominantly the iliopsoas, rectus femoris, or sartorius.

• These injuries range from minor overstretching with microscopic damage (Grade I) to complete muscle or tendon rupture (Grade III).

• Often characterized by localized muscle fiber damage, inflammation, and pain affecting hip flexion strength and function.
  

Cause

• Acute overload or sudden eccentric contraction during activities such as kicking, sprinting, jumping, or rapid acceleration/deceleration.

• Overstretching of the hip flexors during forced hip extension or external rotation.

• Muscle fatigue, inadequate warm-up, muscle imbalances, and poor flexibility increase susceptibility.

• Biomechanical factors including altered pelvic tilt, lumbar spine dysfunction, and hip joint pathology may predispose individuals to strain.

• Sports with frequent hip flexion demands like soccer, hockey, track and field, and martial arts show higher incidence.

• Repetitive microtrauma and overuse can also lead to chronic strain presentations.
  

Classification

Hip flexor strains/tears are categorized based on severity and anatomical location:

• Grade I (Mild): Small number of muscle fibers damaged with minimal strength loss and mild pain.

• Grade II (Moderate): Partial tear involving significant fiber disruption, moderate pain, swelling, and functional limitation.

• Grade III (Severe): Complete rupture of muscle or tendon resulting in severe pain, swelling, bruising, and significant loss of hip flexion power.

Anatomically, injuries may affect:

• Iliopsoas muscle/tendon: Most common, especially at musculotendinous junction or tendon insertion on the lesser trochanter.

• Rectus femoris: Particularly vulnerable due to its biarticular nature.

• Sartorius: Less commonly injured but involved in complex hip flexion and rotation movements.

Imaging (MRI or ultrasound) assists in precise diagnosis, grading, and treatment planning.

Signs and Symptoms

• Sudden anterior or anteromedial thigh/groin pain during activity, often described as sharp or tearing.

• Tenderness and swelling localized over the hip flexor region or groin.

• Bruising/ecchymosis may appear within 24-72 hours post-injury.

• Pain on resisted hip flexion and passive hip extension.

• Reduced strength and flexibility of hip flexion.

• Difficulty with activities involving hip flexion such as walking uphill, stair climbing, kicking, or running.

• Palpable defects or gaps in severe tears.

• Antalgic gait and functional limitations may be evident depending on injury severity.
  

Current Treatment Trends

• Acute phase:

• Implementation of the POLICE principle: Protection, Optimal Loading, Ice, Compression, Elevation.

• Early pain-guided mobilization to minimize stiffness and promote healing.

• Rehabilitation:

• Gradual progression from pain-free range of motion to strengthening exercises targeting hip flexors, hip stabilizers, and core muscles.

• Emphasis on eccentric strengthening to improve muscle-tendon resilience.

• Neuromuscular control and proprioceptive training to restore functional movement patterns.

• Functional and sport-specific retraining prior to return to activity.

• Adjunctive therapies:

• Manual therapy and soft tissue techniques to address secondary restrictions.

• Modalities such as therapeutic ultrasound or low-level laser therapy may be considered, though evidence remains limited.

• Surgical intervention:

• Reserved for complete tendon ruptures or cases with persistent symptoms refractory to conservative care.

• Prevention:

• Focus on optimizing muscle strength balance, flexibility, proper warm-up routines, and biomechanical correction.

• Current evidence supports individualized, criterion-based rehabilitation emphasizing early controlled loading and functional progression for optimal recovery.
  

Conclusion

Hip flexor strains and tears are significant injuries that impair hip function and athletic performance. Accurate diagnosis, severity grading, and tailored physiotherapy management are essential for effective recovery. Early intervention with progressive loading, strengthening, and functional training reduces recovery time and recurrence risk. Surgical repair is typically limited to severe tendon ruptures. A multidisciplinary approach and patient education play key roles in successful rehabilitation.