The main results of this study were that young active females who go on to suffer an ACL re-rupture summarised the first ACL injury as a negative incident, however in contrast, expressed positive experiences and personal growth, reflected by the feeling of ‘a new, stronger, me’ after going through the ACL re-rupture journey.
The main categories resulting from this qualitative content analysis were categorised into positive and negative subheadings. Despite the dynamic biopsychosocial cycles of sport-sport injury response and recovery  being presented as a circle, we chose to present the results on two timelines, starting from 1) ACL injury to the ACL re-rupture, and, 2) from the ACL re-rupture to the time of interview. We deemed the choice to adapt the psychological response to a timeline as appropriate for our data based on our clinical experience. However, we acknowledge that the psychological responses experienced by the patients are not one dimensional, and main categories resulted from data analysis are likely occurring at the same time, and interchanging with each other throughout the journey.
The results of our study are novel in that we interviewed young female patients who have suffered an ACL re-rupture, giving them the unique opportunity to explain factors they believe important for their ACL journey with their own words. The results suggest that patients were deemed ready to RTS by healthcare professionals, however, not feeling ready to return. Despite previous studies reporting impaired knee-related quality of life in ACL deficient individuals,  and ACL reconstructed individuals at least 5 years after surgery,  the patients in our study reported positive experiences, feeling as a new, stronger person, and reported that their knee injuries allowed them to have the opportunity to explore other interests in life. Therefore, to evaluate knee-related quality of life alone, may be insufficient for a holistic and long-term reflection of patients’ satisfaction with the treatment after ACL injury. In addition, symptoms of depression have been reported in patients 5-20 years after ACL reconstruction,  but in our study, we did not find symptoms of depression or impaired self-reported health measured with the MADRS, HADS or SF-36.
When patients were close to returning to sport after their index ACL reconstruction, setbacks were experienced, including pain and swelling of the knee joint, and patients felt they could not completely trust their knee. Patients expressed that their knee did not feel ready for returning to sport, despite passing RTS criteria in a clinical test battery. Therefore, based on the experiences of the patients in our study, the clinical tests we use to assess whether patients are ready to RTS after an ACL reconstruction, do not necessarily comply with whether patients feel ready to RTS. The difference between passing clinical tests and patients’ subjective feelings has recently been highlighted in previous publications, as patients state fear of re-injury as a main component for not returning to sport, . Parallelly, RTS criteria seldom comprise the assessment of fear, and may not identify a subset of patients at risk of sustaining an ACL re-rupture [31, 32]. This mismatch between how clinical healthcare professionals interpret results from clinical tests, and how patients feel about returning to sport, is challenging, especially with respect for shared decision-making. In this aspect, we argue that that the patients’ perspective in shared decision-making for RTS needs further emphasis, and, structured methods to ensure its inclusion is warranted . Although current RTS testing is likely beneficial to determine the minimal level for clearance of returning to sport participation, it must be acknowledged that some of the current objective RTS criteria are of arguable validity and do not capture how patients feel about RTS. We encourage the use of clear and transparent sharing of information from the responsible healthcare professionals, while the final decision of RTS should be taken by the patients themselves.
The patients in this study expressed that early and limited participation in their sport after ACL reconstruction could be detesting, where patients felt that they only could watch teammates play the sport, while they were standing on the side line. It has previously been reported that patients believe social support is crucial of a successful rehabilitation . However, the interpretation that social support is passive and enforced by allowing patients to perform rehabilitation tasks at the same time and place where other teammates train, may have been made by healthcare professionals, and never been validated by patients themselves. Some of the patients in the present study mentioned that being part of the team and being able to participate in team activities, such as trainings, was important for returning to sport and finding the strength and motivation to proceed through rehabilitation, a finding which is in accordance with previous research on elite female football players . Whether social support should be provided ‘on field’ or not is likely individual and should be adapted from patient to patient.
Since moved from a constructionist theoretical framework, which assumes that reality is constructed through interaction in human practices between a subject and a certain event, it is possible to assume that different patients have different experiences of the same event. Therefore, since qualitative content analysis is suited to study different realities, descriptions and experiences of patients within a population, it was deemed as a suitable method for the present study. One problem when conducting mixed method research is the challenge of coordinating qualitative and quantitative data in a credible way. In our study we chose to have a dominant qualitative design accompanied by quantitative data in order to explore our presumptions that young females who suffer an ACL re-rupture would present symptoms of depression and/or anxiety as well as a lower self-reported health status after going through the second ACL rehabilitation. We did not base our result on the quantitative part of the study, which should be seen merely as descriptive. One crucial aspect of conducting qualitative research concerns data saturation. In our study, we included 15 patients, and we repeatedly read the interview transcripts in order to validate the main, sub-categories, codes and condensed meaningful units, to ensure that all data was relevant for the aim of the study. During this process of the analysis, we noticed that neither further codes, nor subcategories could be extracted in the last analysed interviews. We therefore feel positive that data saturation was reached. In addition, two experts in sport and exercise psychology, highly trained in qualitative research helped in triangulating the steps of the analysis process.
The patients in the present study were recruited from a geographical area where a rehabilitation specific registry for ACL injury is available, which provides patients with the opportunity for continuous evaluation of progress in the rehabilitation. It is possible that the patients included in the present study might have a greater motivation towards rehabilitation than other patients, since they participate in Project ACL and are continuously assessed with test of muscle function and PROs, which previously has been associated with stronger motivation for rehabilitation. Another limitation is that patients were recruited from the same geographical area, therefore their experiences are influenced by the culture of the place in which they live. Furthermore, we chose to only include young active women, which is the subgroup of patients with the greatest incidence of ACL re-ruptures. A further limitation is the risk of recall bias, as several months had passed between first ACL injury and time of interview. However, the key concept in our result is that the first ACL injury is seen as a negative event, in contrast to the ACL re-rupture which had instead positive nuances. Therefore, we do not believe recall bias to have altered the loading of the feelings with regard to the ACL injury. The sharp inclusion criteria (young sports active females) limits generalisability of our results, and they should therefore be appreciated with caution.