Groin Strain

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Original Editors - Els Van Haver

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Search Strategy

Keywords:
Groin Strain – Adductor Strain – Groin pain – Adductor rupture – Groin avulsion – Groin injuries
Databases searched:
Pubmed, web of science, Vubis catalogus, ...

Definition/Description

A groin strain or a groin pull is an acute tear of the small fibers muscle-tendin unit of the adductor muscles. This tear can be partial or complete. Groin strain is usually due to an acute stretch of the muscle often at the same time of a forceful contraction or repetitive (functional) Overloading. For example a sudden sprint taken by a soccer player. When the adductor muscles are extended by an eccentric contraction, high muscle forces are generated during the extension and added to the forces created by the passive connective tissue so it almost certainly induces a muscle strain injury. This force is several times higher than the force produced during a maximal isometric contraction (<R> http://www.physio-pedia.com/Quadriceps_Muscle_Strain)

Groin strain is most of the time a sports-related injury.

Clinically Relevant Anatomy

The adductor muscles are a group of muscles that are located on the inner side of the thigh. They start in the groin area and run down the inner thigh to attach to the inner side of the knee. They are particularly active when suddenly changing direction and unexpected movements.

Their origin is in the groin area (os pubis and os ischia) and run down the inner thigh to attach to the epicondylus medialis. The pectineus originate at the pectin ossis pubis, the musculus adductor longus at the ramus superior of the os pubis and the other adductors (brevis, magnus, minimus) originate at the ramus inferior of the os pubis.The fibers range vertical.

The adductors of the hip (<R> http://www.physio-pedia.com/Hip_Anatomy#Muscles) joint consist of 6 muscles:
• musculus gracilis
• m. pectineus
• m. adductor brevis
• m. adductor longus
• m. adductor magnus
• m. adductor minimus

These muscles are innervated by the obturator nerve. Additional innervation happens by the femoral nerve for the m. pectineus ¹  and the tibial nerve for the m. adductor magnus.

The foremost function of the adductor muscles is adduction of the thigh in open chain movements and stabilization of the lower extremity and pelvis in closed chain movements and also stabilising the trunk during lateral movements when walking, running and changing direction to the lateral side… ⁴

 

Epidemiology /Etiology

CAUSES :

- When the adductor muscles are stretched beyond the amount of tension they can withstand a groin strain can  appear. Insufficient warm up ⁵
- Other causes are abruptly putting stress on the adductor muscles when they are not ready for stress. ⁵
- Overusing the adductor muscles^.6
- Getting a direct blow to the adductor muscles.

RISK FACTORS :

- Groin strain occurs due to a sudden contraction when the groin muscles are in a position of stretch. Typically    during rapid acceleration. The overstretching of the leg and thigh in abduction and external rotation. ⁶
- Previous strain or injury to the area. ^1,7
- Muscle fatigue or weakness.⁸
- BMI ⁸
- Poor conditioning and imbalance of musculature⁸
- Age ^8,9
- Abnormality of bone structure. ¹⁰
- Participation in sports that require bursts of speed are a huge risk factor for causing a groin strain. This includes  track sports like running, hurdles or long jump. Also sports like soccer, football, rugby or basketball. ¹¹

Characteristics/Clinical Presentation

The most common sign of a groin strain is a sudden sharp pain or pulling sensation during activity in the inner thigh During activities the patient experience an increase in pain. Other symptoms can be pain, tenderness and stiffness in the groin area. Also weakness of the adductor muscles can be a symptom. Another symptom can be a bruising in the groin area if blood vessels are broken and popping or snapping sensation as the muscle tears. Also pain when you bring your legs together, pain when you raise your knee. ¹²

Differential Diagnosis

In general muscle strains can be graded into 3 grades according to their severity. Grade 1 some stretching with micro-tearing of muscle fibers. With grade 1 there’s no loss of strength just tenderness and discomfort. Grade 2 partial tearing of muscle fibers and contains also tissue damage. Second-degree strains involve swelling and a decrease of range of motion and strength. Grade 3 contains a complete tear of the muscle fibers, resulting in complete functional loss of the affected muscle. We also call this a rupture or avulsion. The most common groin strain are second-degree strain. The most affected muscle is the adductor longus. ^12,13

Most groin strains can be diagnosed with a physical exam. The doctor may want images of the area if severe damage is suspected. Images may be taken with MRI.

Diagnostic Procedures

Further investigations such as an MRI scan or Ultrasound may be required. In rare cases to confirm diagnosis and assess the severity of injury.

Patients with chronic pains are more difficult to diagnose. There pain is more diffuse and that is difficult to attribute to specific structures. The presentations for osteitis pubis, sports hernia (<R> http://www.physio-pedia.com/Pubalgia) and chronic adductor pain are quite similar and can present simultaneously. Plain radiographs or a bone scan can sow typical changes of osteitis pubis and herniography can rule out sports hernia. Ultrasound of MRI can evaluate the tendon structure for intrasubstance abnormalities.¹⁴

Outcome Measures

Strength testing ¹⁵

The best way to test strength and inhibition of the adductor muscles is through the ‘Adductor Squeeze’ test ¹⁶. This is done with the patient lying on the table with the legs extended. The examiner places two clenched fists together between the patient’s knees and the patient then squeezes the knees onto the examiner’s fists. With acute injuries, it is advisable that the patient is instructed to slowly build pressure until maximum pressure is achieved. Pain and inhibition are then subjectively assessed. The same test is then done with the feet up on the table and the knees bent to 45 degrees. The third and final position is feet off bench with hips at 90 degrees. It is necessary to test all three positions, as acute tears may actually be pain-free in one of these testing positions.¹⁷ Level of evidence: 3B

The purpose of these tests is to qualify pain and inhibition at all testing positions and to gain some ‘asterix’ points for re-assessment in the near future.

Examination

The patients typically complain about aching groin or medial thigh pain and often relate a specific inciting incident. Sometimes acute rupture and osseous avulsion of the proximal adductor longus can be reported.

The passive examination learns the physiotherapist there is tenderness to palpation with focal swelling along the adductors and decreased adductor strength. While testing the muscle strength the pain will increase with resisted adduction.^14,18,19

Prevention ²⁷

- Keep your adductor muscles strong to absorb the energy of sudden physical stress
- Exercise program
- Learn the proper technique for exercises and sports
- Warm up your muscles slowly and stretch them properly

Medical Management

Most of the times the management is nonoperative. Injection at the adductor longus enthesis is helpful. In cases of acute rupture, open surgical repair with suture anchors has been described with good results.

NSAID’s (non-steroidal anti-inflammatory medications) can be used to control pain and decrease the swelling. Furthermore there is no need of other medication. (<R> http://www.physio-pedia.com/NSAID_Gastropathy)

Physical Therapy Management

The therapy can be divided into 4 stages. ²⁰

The first stage will implicate the RICE principal: Rest, ice, compression and elevation. This stage is designed to limit the swelling and prevent any further injury. Rest until pain free. This way the muscle can heal appropriately. When you rest inadequately it may prolong the recovery. Allow pain to guide your level of activity. Avoid activities that place extra stress on these muscles. Don’t do activities that cause pain (running, jumping and weight lifting using the leg muscles ). If normal walking hurts, shorten your stride. And do not play sports. This stage continues until the pain and swelling decrease (can depends from 2 days till one week). NAIDS can be used to control pain and decrease the swelling. The applying of ice is recommended in the first 48 hours after the injury as well later on after activities. Ice stimulates the blood flow to the injured area and calms the inflammatory response, ^10,16,20,24 hoogste level of evidence 1B.

The second stage is based on limiting atrophy and restore the ROM (Range of Motion). It begins with gentle passive and active assisted motion. The exercises containing to improve the range of motion must be limited by the pain,²¹ level of evidence 1A. Stretching can be helpful as long it is not painful. When you stretch excessively, it can be harmful and it will slow the recovery and healing process. When the acute pain is gone, start gentle stretching as recommended. Stay within pain limits. Hold each stretch for about 10 seconds and repeat 6 times. Stretch several times a day. Sometimes ultrasound (<R> http://www.physio-pedia.com/Ultrasound_therapy) and electrical stimulation (<R> http://www.physio-pedia.com/Transcutaneous_Electrical_Nerve_Stimulation_(TENS)) can be added, although it has not fully scientifically verified.

Stage 3 begins when the patient has a nearly full range of motion pain free. It’s based in regaining strength, flexibility and to improve the endurance. First we train isometric and isokinetic, starting with low weight and 3-4 repetitions. We can progress to heavier weight and fewer repetitions as the pain free strength improves,²² Level of evidence 1B.

The fourth and final stage includes proprioceptive training, sport specific training (very important because most of our patients with groin strains are athletes). Eccentric training is allowed in this stage, because this stage can begin only when the patient is pain free and reached about 70% of his normal strength,²³ level of evidence 1A.

The key component of rehabilitation for groin pain in athletes is the exercise therapy. Exercise, particularly strengthening exercise of the hip and abdominal muscles is important. Recommended to do the exercises in the form of progressive exercises (static to functional) and performed through range,¹⁸ level of evidence 2B.

Stretching exercises can be used in prevention and also as an extra factor after the acute phase and there can be added manual therapy ,²⁴ level of evidence: 1B. 2 examples of stretches are:

Groin squeezes:²⁵

Begin this exercise by lying in the position demonstrated with a rolled towel or ball between your knees. Slowly squeeze the ball between your knees tightening your groin muscles (adductors). Hold for 5 seconds and repeat 10 times as hard as possible pain free.

Groin Stretch:²⁶
Stand tall with your back straight and your feet twice shoulder width apart. Start a lunge to one side, the other knee remains straight, until you feel a stretch in the groin.Hold 5 seconds and repeat 10 times at a mild to moderate stretch provided the exercise is pain free.

Key Research

Tyler, Timothy F., et al. "Groin injuries in sports medicine." Sports Health: A Multidisciplinary Approach 2010; 2.3: 231-236.
Evidence Based Practise: 1A

Jarvinen Markku, et al. Groin Pain (Adductor Syndrome). Operative Techniques in Sports Medicine 1997; 5(3): 133-37.
Evicence Based Practice: 5

Tyler, T. F., Silvers, H. J., Gerhardt, M. B., & Nicholas, S. J. (2010). Groin injuries in sports medicine. Sports Health: A Multidisciplinary Approach, 2(3), 231-236.
Evidence Based Practice: 1A

Resources

Video assessment techniques for Groin Injuries:

https://www.youtube.com/watch?v=VfAKc6_FbLQ

Video squeeze test: 

https://www.youtube.com/watch?v=--W5G9lP7pM

Clinical Bottom Line

Conclusion: there is support for an association of precious injury and greater abductor to adductor strength ratios as well as sport specificity of training and pre-season sport-specific training, as individual risk factors for groin strain injury in athletes. Core muscle weakness or delayed onset of transversus abdominal muscle recruitment may increase the risk of groin strain injury. Debate does exist in the literature reviewed regarding the role of adductor strength and length as well as age and/or sport experience as risk factors for groin injury. 

Recent Related Research (from Pubmed)

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Serner, A., Tol, J. L., Jomaah, N., Weir, A., Whiteley, R., Thorborg, K., & Hölmich, P. (2015). Diagnosis of Acute Groin Injuries A Prospective Study of 110 Athletes. The American journal of sports medicine, 43(8), 1857-1864.

References

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