This randomized clinical trial aimed to examine and compare the efficacies of AB, CS, and a combination of both (AB + CS) for treating lateral epicondylitis (LE). The hypothesis posited that the combined injection might offer superior results in terms of fast symptom resolution and a lower recurrence rate by leveraging the initial action of CS and the regenerative potential of ABI. Our results highlighted that by day 15, all treatment modalities had produced significant improvements in PRTEE scores, with the CS group showing a more pronounced reduction compared to the other groups. However, this early gain in the CS group started to deteriorate by day 30 and continued till day 90, emphasizing the transient relief provided by CS injections. On the other hand, the ABI and combined-injection groups showed continued improvements in PRTEE scores, substantiating the role of these treatments in consistent symptom reduction and potentially addressing intrinsic tendon degeneration. The combined AB + CS treatment emerged as the most effective modality, with substantial clinical improvement and minimal failed treatment instances. This observation implies that a potential synergistic mechanism underlies the combined treatment approach, suggesting that a multimodal therapeutic strategy may yield more enduring and reliable relief for individuals afflicted with lateral epicondylitis.

CS injections have been used since the 1950s as a treatment strategy for LE [3, 16]. Although the mechanism of action could not be explained in detail, it is proposed that CS may decrease some inflammatory mediators and neuropeptides such as Substance P, calcitonin gene-related peptide, and neurokinin-1, which are responsible for the pain. Thus, the injection of CS relieves pain immediately. However, it cannot reverse the degeneration process to regeneration within the tendon, and the symptoms turn back on a few weeks after the injection, when its inhibitory effect ceases. Several authors have shown the temporary effect of CS. Furthermore, some authors even hypothesize that CS injections worsen long-term results by either weakening the tendon or by allowing patients to further aggravate their tendinosis initially by relieving pain in the short term [17]. Similarly, in our study, we observed this pattern clearly.

Edwards and Calandruccio first described AB injection for the treatment of LE. They reported a 79% success rate (22 out of 28 patients) in their series [9]. The mechanism of action of AB injection is also not known, but it is believed that cellular and humoral mediators found in blood initiate the healing cascade of the tendon and reverse the degeneration to regeneration, in contrast to the action of CS. Since then, several authors have shown that AB injection is an effective treatment for LE, with no serious side effects. In the current literature, few studies compare CS and AB injections for the treatment of LE (Table 5) [10, 11, 18,19,20,21,22,23,24,25]. Of these studies, only one study could not demonstrate any significant difference between AB and CS. Wolf et al. performed a randomized clinical trial (RCT) of 28 patients in which AB, CS, and a saline injection were compared. In this study, the patients were evaluated with VAS, DASH, and the patient-related forearm evaluation 2 weeks, 2 months, and 6 months after injection. According to the study’s outcomes, all groups demonstrated an improvement from baseline, but there were no significant differences in any of the groups [18]. Apart from that study, the other studies reported superior clinical outcomes with AB injections. However, the current study introduces a novel perspective by incorporating a combined-treatment approach. The impressive clinical improvement and sustained benefits observed with AB + CS suggest that this combined modality may offer a balanced and superior alternative, providing both immediate relief and long-term recovery. This aligns with the findings of Lee et al., where a combined approach showed better results during the initial period, although the improvements were similar by the 6th month [25].

An ideal treatment of LE should ensure immediate pain relief, a fast return to daily activities and work, and a low recurrence rate. Any treatment method that provides these goals faster than other options is advantageous. In this study, we attempted to optimize the current injection technique by combining two available options. We utilized the immediate pain-relieving effect of CS and the long-term regenerative effect of AB. Although AB injection alone and AB plus CS injection resulted in similar final clinical outcomes at the final follow-up, the the combined treatment had longer-lasting effects on function.

This study has some strengths and limitations. The follow-up period was relatively short, limiting the assessment of the long-term efficacies and recurrence rates of the treatment modalities. This study was not blinded, which could have introduced bias into the results. On the other hand, this was a randomized clinical trial, which provides a high level of evidence. No patients were lost during the study period, and all patients had similar initial characteristics regarding several parameters.