Research Review by Dr. Shawn Thistle©

Date:

Oct. 2006

Study Title:

A new view on adduction-related groin pain

Authors:

Mens J et al.

Public Information:

Clinical Journal of Sport Medicine 2006; 16:15-19.

Summary:

Groin injuries and complaints are common among athletes, both competitive and recreational. Groin pain can normally be attributed to a few well-defined diagnoses - osteoarthritis of the hip, adductor tendinopathy, inguinal herniation, etc. Other possibilities that are often harder to detect include entrapment neuropathies, myofasciopathy of the abdominal wall musculature, and visceral conditions.

Many patients with groin pain will have an increase in pain with hip adduction - whether active or resisted. Previously, pain with isometric hip adduction would lead to a diagnosis of adductor tendonitis. [More recently, the terminology for tendon pathology has changed and a more appropriate diagnosis would be tendinopathy or tendinosis. This terminology is not the topic of this review, but relevant to mention nonetheless.]

The classic diagnostic signs and symptoms of adductor tendinopathy include unilateral pain near the adductor attachment on the pubic tubercle, with pain provoked by isometric or resisted hip adduction, passive hip abduction, or palpation of the involved adductor musculature.

This paper examined the hypothesis that not all adduction-related groin pain can be attributed to adductor tendinopathy. The authors first justify their use of "adduction-related" vs. "adductor-related", stating that the former implies that the motion is problematic, while not necessarily implicating the adductor muscle group as the latter term does.

Based on previous studies showing that many women with pregnancy-related pelvic pain feel groin pain with resisted hip adduction, the authors hypothesized that not all cases of groin pain exacerbated by resisted hip adduction could be attributed to adductor tendinopathy in an athletic population.

Performed as a cross-sectional analysis, this study included 44 athletes (mean age ~31, mostly men) presenting with the symptoms described above, and no evidence of lumbosacral radiculopathy, inguinal hernia, OA of the hip, trochanteric bursitis, muscle or tendon rupture, systemic disease, or previous pelvic fracture. The majority of the patients played soccer (as an aside, it is mentioned that the one year incidence of groin injuries among male soccer players is 12.5-19%), while other sports represented included tennis, field hockey, basketball, horseback riding, and running.

All patients in this study were recreational athletes (which I feel makes this more relevant to everyday practice). The duration of the injury was quite variable - ranging from 6 weeks to 7 years (median value was 16 months).

Each patient and control subject (n=44) was assessed using the following tests/measures:
  • pain location and side - recorded on a questionnaire which also asked about other locations of pain (posterior pelvis, lumbosacral area etc.)
  • pain level on a VAS (0-100mm)
  • pelvic belt test - hip adduction strength was measured with a handheld dynamometer with the patient supine with knees bent to 90° and feet on the table (squeezed between the knees - see comments below *), with and without a pelvic belt (non-elastic, 5-7cm wide, positioned just inferior to ASIS and superior to greater trochanter)
  • active straight leg raise (ASLR) - previously described by Vleeming et al. in pregnant patients (thought to indicate impaired load transfer through the pelvis) - performed with patient supine with feet 20cm apart, then asked to raise one leg straight off the table ~20cm - pain and difficulty levels reported by patients, then test re-done with the pelvic belt - improvement in pain or difficulty with the belt is a positive test
  • hip adduction strength was standardized in the following way: in healthy subjects, hip adduction strength increased a maximum of 19.5% with the pelvic belt - therefore in order to count as a significant increase in the patient group, hip adduction strength had to increase at least 19.5% with the belt
* While testing hip adduction, it should be noted that subjects contracted both legs at once, basically squeezing the dynamometer between their knees (along with the examiner's fingers). Therefore, side to side strength comparisons could not be made within subjects (i.e. comparing injured to non-injured side) - which in my opinion weakens the results of this study.

Pertinent Results:

  • 17 patients had a positive ASLR - ALL of these patients felt less pain (by 68%) and increased strength significantly with the use of a pelvic belt
  • ASLR was negative in all 44 healthy controls
  • patients who had an increase in adduction force with the pelvic belt had higher pain levels, longer complaint duration, and more frequently complained of pain in the lumbosacral region that controls
  • 32% of patients has pain located in the posterior aspect of the pelvis, and groin pain was bilateral in 41% (remember, adductor tendinopathy is normally unilateral)

Conclusions & Practical Application:

The authors propose that their results support their hypothesis - that poor isometric hip adduction or pain during this test is not always indicative of adductor tendinopathy. In some patients in this sample, a pelvic belt influenced pain and hip adduction strength favourably.

The authors hypothesize that pain caused weakness through reflex inhibition in a proportion of these patients due to instability in the pelvic ring (which would impair force transfer).

I feel the authors make a fair number of assumptions in stating this, but this study does alert the clinician to evaluate pelvic stability and search for additional problem areas in recreational athletes presenting with groin pain. At the very least this study suggests that increasing pelvic stability may improve force transfer through the pelvis.

Suggesting that utilizing the pelvic belt as a clinical test to help classify groin pain patients may be somewhat presumptuous, and would require more research. However, as with all 'functional' tests, using it in the proper context and in combination with other tests may help guide treatment or rehabilitation decisions for groin pain patients.