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.

Prevention

File:Multivariate Analysis.png

Multivariate_Analysis

Subsequent groin strains may occur, resulting in a recurrent problem. Hence primary and secondary prevention are equally important. To identify the athlete at risk and possibly correct the predisposing factor(s), the intrinsic and extrinsic risk factors for the injury type must be known.

A history of previous acute groin injury and weak adductor muscles are significant risk factors. Previously injured players have more than twice as high a risk of sustaining a new groin injury, while players with weak adductor muscles have a 4 times higher injury risk. Therefore it is important to have an adequate rehabilitation before full return to play. 

Preventing the first injury should be a high priority to keep players from entering the vicious cycle of recurrent injuries to the same body part. To accomplish this, the best method may be strength exercises of the adductors. Hölmich et al demonstrated that an 8 to 12 week active strengthening program, consisting of progressive resistive adduction and abduction exercises, balance training, abdominal strengthening and skating movements on a slide board, was effective in treating chronic groin strains. Also coordination exercises (focused on the muscles related to the pelvis), core stability and eccentric exercises are a part of the prevention program.  Heat retainers and stretching of the adductors are also suggested to prevent injuries. 
Whereas a passive physical therapy program of massage, stretching, and modalities was ineffective in treating chronic groin strains. 

File:Ball squeeze.png

Ball squeeze

File:The intervention exercise 1) starting 2)ending.png

The intervention exercise 1) starting 2)ending

File:Sumo squat.png

Sumo squat

File:Side lunge.png

Side lunge

File:Therapy adductor strain injury prevention program.png

Therapy adductor strain injury prevention program

Examination

A complete clinical examination should be performed for every patient with groin pain.
The injured athlete should first be examined by inspection in a standing position to evaluate the alignment of extremities. The patient should then be asked to lie in a supine position in order to be able to check the motion of the hip joint and the flexibility of the groin and hip muscles. Resistive contraction tests of the knee extensors, knee flexors, abdominal muscles, and hip rotators, extensors and flexors, as well as hip adductors and abductors should be performed. 

1) bilateral evaluation of adductor muscle related pain and strength: palpation at the adductor insertion at the pubic bone, adduction against resistance (squeeze tests in 0° and 45°), and passive stretching of the adductor muscles.

If adductor longus muscle is injured pain will be elucidated to the injured area by resisting leg adduction and in passive stretching at full abduction of the hip. Tenderness on palpation is localized to the injury site at the origin of the adductor longus tendon or at the musculotendinous junction. 

2) evaluation of iliopsoas muscle related pain, strength and flexibility: palpation above the inguinal ligament, isometric strength test in hip flexion and a modified Thomas test. 

Thomas Test

3) Abdominal muscle related pain and strength: palpation of the abdominal muscle insertion at the pubic bone and a functional sit-up test and symphysis joint tenderness at palpation. 
The location of the injury was based on a minimum of 1 positive finding on palpation, stretching, or muscle resistance testing. 

Medical Management

File:Diagnostic methods usedin clinical examination.png

Diagnostic methods used in clinical examination

Management is non-operative with rest, ice, compression, and gentle physical therapy or ROM. Injection at the adductor longus enthesis is helpful for patients refractory to conservative management. There is a clear efficacy of nonsteroidal anti-inflammatory agents. Patients may return to sports or other activities after regaining full strength and ROM with resolution of the pain. 
Non-operative therapy should be tried for several months and is successful in most instances. However, if symptoms persist for more than 6 months after an appropriately administered physical therapy regimen and a period of protected weight bearing with crutches until the patient is pain-free, then surgical intervention should be considered. Adductor tenotomy has been suggested as a technique to improve symptoms. However, this is an end stage option to be tried only after all conservative methods have failed. 

Physical Therapy Management

The treatment of musculotendinous groin injuries is generally conservative. Surgical treatment in acute groin injuries is rarely indicated. 

Conservative treatment
In the treatment of muscle-tendon injuries, immobilization should be limited to as short a period as possible to avoid the harmful effects of immobilization including muscle atrophy and loss of function. Immediate rest after the injury should be used until a diagnosis is secured.
- The primary goal of the treatment program is to minimize the effects of immobilization, regain full range of motion, and restore full muscle strength, endurance and coordination. Therefore, crutches, local cold application, and anti-inflammatory medication are recommended in the initial phase. Muscle exercises can usually be started early, but training should be performed within the limits of pain with careful isometric contractions against resistance.
- After the initial phase, heat is usually valuable, especially when muscle training is started. In general, exercises are performed in a pain-free range of motion and increased pain should not occur after activity.
- As rehabilitation progresses, mild pain can be allowed during exercise, but it should subside immediately after the cessation of training.
- When full range of motion is accomplished, the injured muscle and tendon tolerates higher loads and the goal of rehabilitation should shift towards specific strength training exercises aiming for muscular recovery, increased endurance and full range of motion.
- The final step is the gradual return to sports activity, which may in some cases take as long as 3 to 6 months. 

Adductor muscle strain injury program
progressing the patient through the phases of healing, has been developed by Tyler et al. and anecdotally seems to be effective (table 1). This type of treatment and rehabilitation programme, which combines modalities and passive treatment immediately, followed by an active training programme emphasising eccentric resistive exercise, has been supported throughout the literature. 

File:Adductor strain postinjury program.png

adductor strain post injury program

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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