The most important finding of this study is that patients with higher preoperative psychological competitive ability were more likely to have stronger positive emotional states at six months after ACL reconstruction, although emotional state did not seem to be associated with the rate of returning to sports at six months. Individuals with higher preoperative psychological competitive ability scored significantly higher in preoperative positive factors, although there was no statistically significant difference in preoperative TMD. At six months after ACL reconstruction, there was a significant difference in TMD, and the difference in positive factors increased.
To the best of our knowledge, this is the first prospective study to demonstrate the relationship between psychological competitive ability and emotional states after ACL reconstruction. Psychological factors have been associated with performance in competitive sports and the risk of developing disorders, such as overuse injuries [14]. Many reports [15, 16] have indicated that associations between ACL injury, fatigue, and overuse could be an important indicator of recovery. The DIPCA.3 diagnoses psychological and mental abilities as general characteristics necessary for athletes in game situations, and those with higher performance show higher scores [17–19]. Based on these reports, patients in the present study were grouped according to DIPCA.3 to assess the changes in the emotional state and rate of returning to sports of athletes with higher performance. The results show a statistically significant difference in VA and F items of the POMS2 before ACL reconstruction, and in FI, VA, F, and TMD at six months after ACL reconstruction.
The main goal of ACL reconstruction for athletes at the competitive level is a safe return to sports after reconstruction, while those with good psychological and functional status preoperatively have been reported to show good results after ACL reconstruction [20]. In addition, optimism [20] and self-efficacy [21, 22] have been reported to contribute to the association between preoperative psychological factors and favourable postoperative outcomes, and negative emotions may have a negative impact on return to sports, daily life situation, and quality of life [23, 24]. These findings suggest that positive emotions may have a favourable effect on postoperative outcomes. In this study, the positive items VA and F were significantly higher in the high group than in the low group preoperatively and six months after ACL reconstruction. The high group was shown to have significantly higher cooperation in DIPCA.3. In light of these results, the high group was thought to exhibit more positive feelings about interacting with others, suggesting that this had a synergistic effect on vitality and other factors. Furthermore, FI was significantly lower and VA was significantly higher in the high group than in the low group, indicating that they were more active and energetic, and felt less fatigue at six months after ACL reconstruction. As a result, TMD was also significantly lower in the high group than in the low group. The mood profile of POMS2 in the high group at six months after ACL reconstruction was the iceberg profile reported by Morgan et al. [25], which is said to be exhibited by top athletes and athletes who have achieved success in sports. In the iceberg profile, AH, CB, DD, FI, TA and TMD are low and VA is high, and the figure shows an iceberg shape with VA being prominent. In a recent meta-analysis [26], it was concluded that the iceberg profile of POMS2 is an effective indicator for understanding and improving the performance of athletes. Glazer [27] also reported that psychological readiness to return to sports was negatively correlated with TMD. These results may indicate that athletes with higher preoperative psychological competitive ability have better emotional states at six months after ACL reconstruction and are more psychologically ready to return to sports.
However, we found no statistically significant difference in the rate of returning to sports at six months after ACL reconstruction between the two groups, indicating that preoperative psychological competitive ability was not associated with the return to sports at six months after ACL reconstruction. Thus far, there have been no reports on the relationship between the DIPCA.3 and return to sports after ACL reconstruction; therefore, it is difficult to draw a strong conclusion from this study alone. Recent reports have recommended that the time to return to sports after ACL reconstruction should be nine months or later from the perspective of functional improvement and re-injury [22, 28]. Based on these considerations, an evaluation nine months after the surgery is considered necessary.
The results of this study suggest that enhancing preoperative psychological competitive ability may influence success in sports activities after ACL reconstruction. In order to increase preoperative DIPCA.3, adopting a psychological approach, including active goal setting, having a role model the patient can relate to, relaxation techniques, and mental practice, has been proposed as a strategy to target psychological factors [29, 30]. The POMS2 results obtained in this study also suggest that a favourable surrounding environment, including friendship, is also an important factor in improving psychological competitive ability. Although psychological responses improve with general rehabilitation [20], this study indicates the importance of psychological approaches in improving preoperative DIPCA.3.
This study has several limitations. First, other factors not considered in this study are associated with the return to sports after ACL reconstruction. Further, this study did not investigate the relationship between ROM, muscle strength, and other criteria described in the rehabilitation protocol. Second, we did not conduct a psychological approach to the patients, and it is unclear how a psychological approach would affect the results of this study. This is a major issue that needs to be addressed in the future, and collaboration with more specialized professionals, such as sports psychologists and clinical psychologists, is necessary. Third, DIPCA.3 was performed only preoperatively and was not assessed six months after ACL reconstruction. Although a psychological approach is required to improve psychological competitive ability, DIPCA.3 was not assessed at six months postoperatively because no psychological approach was used in this study.