What is an Adductor Muscle (Groin) Strain?

• An adductor muscle strain is an acute injury to the groin muscles on the medial aspect (inside) of the inner thigh. Although several different muscles can be injured, the most common include the Adductor Longus, Medius, and Magnus, and the Gracilis.
• Strains reflect tears of the muscle-tendon unit, due to forceful contraction of the muscles against resistance, often during an eccentric load (Eccentric refers to a muscle contraction while the muscle is lengthening, versus Concentric, in which the muscle shortens during the contraction).  Most weight-lifting involves concentric contraction; “Negatives” during bench press is an example of an eccentric contraction.
• Tears can occur at muscle origin or insertion, at the muscle-tendon junction, or within the belly of the muscle(s).  Most commonly, tears occur at the muscle-tendon junction.  Uncommonly, the tendon injury occurs at the site of its’ bony attachment.
• Strains can be graded I-III, depending upon their severity.  Grade I involves a mild strain with some injury, bleeding, tenderness, but no significant fiber disruption.  A Grade III injury involves disruption such that there is loss of overall tendon integrity.  A Grade II injury involves injury to the muscle-tendon fibers but the overall integrity of the muscle-tendon unit is preserved.
• Most adductor strains are Grades I or II.

How does it occur?

• Most commonly, strains occur during acute muscle contraction, such as when kicking, pivoting or skating. Factors that can predispose to injury include failure to warm up, properly stretch, or fatigue from overuse.

Risk increases with:

• Sports involving acceleration such as sprinting, soccer, football, hockey.
• Sports with repeated movements such as soccer, martial arts, and gymnastics.
• Failure to warm up, stretch or be properly conditioned.

What are the symptoms?

• Sudden onset of pain, sometimes accompanied by the sensation of a pop in the inner thigh.
• The athlete typically is unable to continue their activity.

How is it diagnosed?

• History and physical exam are usually sufficient to establish the diagnosis
• Physical findings include tenderness to palpation (touch), bruising over the inner thigh and sometimes, swelling and warmth over the site of injury.  With severe tears there may be a palpable defect over the site of the injury, though this is uncommon.
• Range of motion testing of the hip is usually normal, but pain is usually reproduced when the patient is asked to contract the muscles. In this case, asking the patient to bring their leg towards midline (adducting their leg) reproduces pain and is usually accompanied by weakness.

Are there any Special Tests?

• Special tests are typically unnecessary.
• X-rays are almost always negative, but are appropriate in cases in which there is tenderness at the site of bony insertion, or in skeletally immature athletes/patients (ie kids).  In children, attachment sites of muscle/tendon units are vulnerable to fracture and are actually weaker than the muscle/tendons.
• MRI is indicated in elite and professional athletes, in which injury location and extent may help in prognosticating return to activity, or in rare cases, help identify cases that require operative treatment.

How is it treated?

Non-operative treatment:

• Nearly all muscle strains, including the adductors, are treated definitely with non- operative management.
• Initial treatment includes activity modification to avoid pain and may temporarily include crutches.
• Ice to reduce swelling and pain medication are appropriate for all acute muscle strains.
• As symptoms improve, gentle stretching and strengthening exercises are appropriate.
• Many of these exercises can be performed independently but are initiated under the care of a physical therapist or trainer.

Operative (or Surgical) treatment:

Surgery for these injuries is rarely necessary.  Uncommonly, avulsions (injury in which the tendon is pulled away with its bony attachment), if significantly large or displaced, may require operative reattachment.

• Some cases of complete muscle tendon tears may also on rare occasion require surgery.  Repair involves an open incision over the site of injury and reattachment of the tendon origin or suture repair of torn soft tissue.
• Surgery is also occasionally necessary in patients with chronic pain that does not respond to non-operative treatment.

Treatment Complications:

Possible complications of non-operative treatment include:

• Chronic pain, abnormal gait, restricted hip/knee motion, weakness and inability to return to activity.

Possible complications of operative treatment include:

• Stiffness following repair and obligatory protection against repair stress (such as not permitting the leg away from the body’s midline for 6 weeks
• Persistent weakness and/or pain
• Failure to return to the pre-injury level of activity. 
• Other complications not specifically associated with adductor muscle repair include bleeding, infection, nerve injury, and problems with anesthesia, all of which are uncommon. 

When can you return to your sport/activity?

• Time out of activity varies greatly with the extent of the injury.  Most strains start to improve within 10-14 days, and continue to improve over many months.
• A severe strain may require crutches for several weeks and take a longer recovery period.
• Some patients will continue to struggle with mild chronic symptoms of pain for more than 6 months.

How can an Adductor Muscle Strain be prevented?

• Most (but not all) strains can be avoided through proper warm up and stretching before practice and competition.
• Flexibility stretching should include the hip, thigh and knee
• Avoid premature return to activities following rehabilitation for injury and or following surgery.