Studies on the use of steroid injections for groin tendon problems are not plentiful. Research shows that one to three steroid injections of soft tissues for acute and/or chronic inflammatory pain can be beneficial. More than that and the risk outweighs the benefit because steroids are known to break down collagen fibers that make up tendons and muscles.
But if you obtained pain relief the first time and it lasted eight weeks, chances are a second injection might resolve the problem for you. Some of it may depend on your activity level and any anatomical or postural issues that might be contributing to the problem.
Some additional testing might be helpful. MRIs with contrasting dye can offer useful information. If you are a competitive athlete (participating in your sport four or more days each week), your risk of recurrence is much higher. This is likely because your activity level is high enough to repeatedly cause microtrauma of the affected tendon(s). A positive MRI showing uptake of the dye into the damaged tendon is a predictive factor for symptom recurrence in competitive athletes.
For recreational athletes (participating in any sports activity less than four times per week), the MRI findings are not as predictive. Some folks don’t have any sign of tendon pathology on the MRI but still get pain relief from the steroid injection. With a lower activity level and greater ability to rest between sports activity, recreational athletes seem to benefit from the injection regardless of the MRI results.