PurposeA great number of patients that suffer from lateral epicondylitis, commonly called tennis elbow (TE), are not successfully treated, meaning, not getting adequate therapeutic effects and the main origin of the pain not being handled appropriately. The hypothesis of the present study is that the inefficiency of the treatment of the chronic TE may often be due to underdiagnosis of posterior interosseous nerve (PIN) entrapment or and plica syndrome, as the authors believe that those pathologies can often occur simultaneously.MethodsA prospective cross sectional study was conducted. A total of 31 patients met the required criteria.ResultsThirteen (40.7%) of the patients had more than one source of the lateral elbow pain. Five patients (15.6%) had all three examined pathologies. Six patients (18.8%) had TE and PIN syndrome. Two patients (6.3%) had TE and plica syndrome.ConclusionThe present study demonstrated concomitant potential sources of lateral elbow pain in patients diagnosed with chronic TE. Our analysis shows how important it is to systematically diagnose patients that present with lateral elbow pain. The clinical characteristics of the three most common causes of chronic lateral elbow pain, meaning, TE, PIN compression, and plicae syndrome were also analyzed. Having adequate knowledge about the clinical aspects of these pathologies can help with a more effective differentiation of the etiology of chronic lateral elbow pain, and with that, a more efficient and cost-effective treatment plan.