Dear Editor,

It was with great interest that we read the paper by Kandil et al. [1] titled “Allogeneic platelet-derived growth factors local injection in treatment of tennis elbow: a prospective randomized controlled study” published online ahead of print, 2022 Jan 12, of International Orthopaedics. The authors found that local injection of allogeneic platelet-derived growth factors is a promising and safe option for treating tennis elbow with significant pain relief, functional improvement, and patient satisfaction. It is a valuable study. We would like to congratulate their laudable efforts in performing this meticulous study. However, there are some issues that we would like to communicate with the authors.

  1. 1.

    Tennis elbow is a self-limiting disease; 70–80% of patients may resolve spontaneously within one year [2]. Therefore, a subset of patients with tennis elbow may experience self-healing, which may affect efficacy evaluation and comparison between the two groups. The time between onset and first visit of patients, personally, can be increased based on the comparison of baseline characteristics between the two groups, reducing the impact of the self-healing rate on the outcome.

  2. 2.

    The authors adopted appropriate statistical analysis methods to analyze the data. But in our opinion, it is difficult to define the follow-up time. For example, patients with poor treatment outcomes in the control group are likely to turn to other treatments during the follow-up period. Therefore, we wonder whether the authors, during the follow-up, encountered such a situation. And it needs to be stated in the article.

  3. 3.

    This study innovatively applied lyophilized human platelet growth factors (L-GF) to the conservative treatment of tennis elbow, providing a new idea for clinical treatment. The authors mentioned that, in the technique of injection, injection was done with single skin entry and multiple pricks in the tendon of extensor carpi radialis brevis would be helpful in curative effect to a certain extent.

  4. 4.

    In the discussion part, the author compares the advantages and disadvantages of PRP and L-GF in terms of efficacy, preparation method, safety, and other aspects by analyzing the current relevant literature reports, and the results are convincing.

  5. 5.

    The occupation of the patients was not distinguished in this study, which will not only affect the distinction of the degree of injury of the patients, but also have different needs for functional recovery in the later stages of different occupations, which will have a certain impact on the satisfaction of the patients [3].

In conclusion, we would like to voice our cordial thanks to Kandil et al. [1] as a result of their hard work, once again. To reach a definitive conclusion, additional studies with larger sample sizes are needed to emphasize these conclusions.