Return to Sports,Return to Preinjury Sports,Return to Prior Performance at Sports: All Meaningful Parameters With Different Meanings and Scales

The most important question on an athlete’s mind with a serious knee injury (besides asking about treatment and surgery) is “When will I be able to return to sports?” Fortunately, there has been a total resetting in the past 10 years of the treatment algorithms to accomplish a safe return to sports (RTS) and decrease the risk for a repeat knee injury. Previous anterior cruciate ligament (ACL) publications seldom listed RTS objective criteria, and “time from injury” was the usual nonscientific rule.^2,9 Today, we have many available assets to utilize for our athletes in defining the process to be followed for RTS with assistance from our physical therapy and athletic trainer colleagues. This is the team approach we follow that is so necessary for treatment of our injured athletes. ⁹

The study by Svantesson et al ¹² entitled “Only 10% of patients with a concomitant medial collateral ligament (MCL) injury return to their preinjury level of sport 1 year after ACL reconstruction: a matched comparison with isolated ACL reconstruction” reports their findings on RTS parameters. The authors employed in their study design necessary postoperative parameters recommended for clinical practice and inclusion in RTS publications. The authors used common patient-reported outcomes, the Knee Injury and Osteoarthritis Outcome Score, Patient Acceptable Symptom State, the Swedish Knee Self-Efficacy Scale, and objective criteria with muscle-strength isokinetic concentric tests and muscle function tests (single-leg hop for distance, side hops timed, vertical hop). These later function tests are now viewed as a “standard of care” in RTS evaluations as a part of an objective battery of RTS tests. It is also recognized that research is necessary on the objective function tests selected for RTS evaluations with the idea of incorporating agility testing and more reactive athletic tasks that simulate athletic reactive activities.^9,15

Of special note is the incorporation of the ACL-Return to Sport after injury (ACL-RSI) assessment. ¹⁴ This psychological evaluation consists of 12 questions in categories of emotions, confidence, and risk appraisal (0 to 10 Likert scale), with the highest value representing complete and total confidence for returning to athletics. From a reality standpoint, after an ACL injury and surgery, the question is to determine the loss of confidence with low values on the ACL-RSI scales. The realization is that our younger athletes (and even older athletes) have serious fears of reinjury and loss of confidence that require our attention and further evaluation before the return to athletics. ¹⁴

The development of the Swedish National Knee Ligament Registry, comprising 90% of all ACL reconstructions in Sweden, and the Project ACL registry are major advances for clinical research and the founders and researchers are to be congratulated. Resulting registry publications have often strengthened treatment approaches and led to major changes in treatment by detecting failures, complications, and overall negative or successful outcomes.

In the Svantesson et al ¹² study, the 1-year follow-up of ACL reconstructions (with and without an associated MCL injury) reported only 10.0% and 25.6%, respectively, return to their preinjury activity levels. This may initially appear to be a negative final result until further analysis is performed. It is true that publications showing an initial lower return to preinjury athletics lets our patients know that, even with expert surgery and rehabilitation, there are good reasons for delaying RTS past 9 to 12 months after ACL reconstruction and especially with concomitant injuries. Studies have shown that at 6 and 9 months after ACL reconstruction, the majority of athletes do not pass knee function and strength testing. Further, early RTS may lead to a 4 times or higher reinjury rate.^3,5,9 In addition to passing RTS tests, there is the added requirement for female athletes to undergo neuromuscular training to decrease the risk of a repeat ACL injury. ⁹ For over 2 decades, we have recommended the nonprofit SportsMetrics neuromuscular training program that has proven statistically significant in decreasing ACL injuries and increasing athletic performance in female athletes. ⁸

In the Svantesson et al ¹² study, the reporting of the low preinjury sports at 1 year, along with the function and strength tests having returned to normal levels, raises the need for further questions. Granted there were only 30 patients in the ACL-MCL group; however, the return of only 3 of 30 ACL patients needs explanation. The question arises whether, given the 10% or even 25% return to preinjury sports, data in the ACL-MCL or ACL groups are truly representative of the final ACL outcomes. The study did show an overall RTS at a Tegner score ≥6 in 46.7% and 48.9% of the ACL-MCL and ACL groups, respectively, which is a more positive outcome. Of importance, the patient demographics shows approximately 60% of the athletes’ preinjury sports were at very high Tegner athletic levels of 8 to 10. This corresponds to highly competitive and national elite athletes and helps us understand there was a shift from this highest athletic rating downward to participation in recreational sports. Perhaps the title should have the addition of “highly competitive athletes” in the title instead of “patients.”

It would have been ideal in the follow-up analysis to pose a straightforward question for those not returning to their preinjury athletics as to “WHY,” with a choice of possible factors. There are of course many factors, often not knee related. In regard to knee-related factors, the Svantesson study reports a low follow-up ACL-RSI score of 59.4 and 57.0 (out of a possible 100) in the ACL-MCL and ACL groups. ¹² The RSI score values are much lower than recommended and reflect issues related to psychological readiness and confidence factors for RTS.

In a recent study, Webster et al ¹⁴ reported on factors that predict a RTS participation in 222 ACL reconstructions evaluated at 1 to 3 years after surgery. A total of 61% returned to their preinjury levels of performance and the study identified a statistical relationship of psychological readiness, greater limb symmetry, higher subjective knee scores, and higher activity levels as associated with a return to performance. Of importance, the only significant RTS predictor was the determination of psychological readiness. The ACL-RSI score (0-100) was reported at 75 on athletes who returned to performance and 64 on athletes who did not return (P < 0.01). Also stressed in this study is that return to athletic performance involves stages of return: (1) return to initial sports participation, (2) a return to sports, and (3) return to performance at the chosen sport. The third phase indicates the athlete performs at or above the preinjury level. The 3 RTS phases have different meanings and the ultimate goal is a return to preinjury sports with return of performance indicators. This raises the bar for determining the final RTS and adds on performance criteria determined by either subjective or objective parameters. ¹⁴ The final RTS rating usually requires 2 to 3 years for meaningful data, and 1-year data are often too soon for accuracy.

An important question raised in the Svantesson et al ¹² study is the prolonged time from injury to ACL reconstruction of 114.6 days and 384 days in the ACL-MCL and ACL groups, respectively. This indicates the patients undergoing ACL reconstruction were usually chronic ACL cases, far removed from participating in high-level competitive athletics. Also reported are associated lateral meniscal tears in 39.2% and medial meniscal tears in 17.5% of the total group. One wonders what the data would show with an earlier intervention of ACL reconstruction and avoiding this extended delay. It would seem the time delay until ACL reconstruction and the associated meniscal injuries would strongly affect the ability to return to high preinjury athletics.

The current study does follow 2 other publications on ACL reconstruction by these authors using the same registries. In a 2018 publication of patients with ACL reconstruction at 1 year after surgery, positive predictors of return to knee-strenuous sports were male sex, younger age, high preinjury level of athletics, and absence of MCL and meniscal injuries. ¹⁰ In a 2019 publication, the authors reported from this database an increased revision rate of ACL reconstructions with a previous nonsurgical-treated MCL injury compared with ACL reconstructions with MCL surgical treatment. ¹³ The analysis of the registry data of the studies is limited by no classification of medial ligament injuries, and the authors indicate knee medial ligament stability test data would have strengthened the study. There is a lack of data on the types of medial ligament disruption preoperative, or findings at surgery, or at follow-up for ACL function or failure, or medial knee stability. In addition to medial ligament stability tests at surgery, there are objective joint opening gap tests that can be performed at arthroscopy.

The question arises in the ACL-MCL group how many knees underwent subsequent ACL reconstruction with abnormal medial joint opening and residual medial knee instability. An associated medial ligament injury and abnormal medial joint opening may have major adverse effects on the success of ACL reconstruction and clinical results.^1,7,9 This criticism is not just an issue with the above studies. There remains controversy on the treatment of medial ligament injuries in highly functioning athletes and, in particular, with a combined superficial MCL (sMCL), deep MCL, and associated posteromedial corner (PMC) (oblique popliteal ligament complex) disruption that involves consideration for surgical treatment over nonoperative treatment. ¹¹ One of the problems leading to controversy is the lack of objective stability data including stress radiography for classification of the medial ligament injury and medial stability preoperative and postoperative. The results of cadaver ligament cutting studies show an approximate 3 mm of increased medial joint opening with a complete sMCL disruption (30° of knee flexion) that doubles to 6 mm increased opening with added PMC disruptions.^4,6 These objective data are needed for studies arriving at treatment recommendations and includes increases in medial joint opening, external tibial rotation, and internal tibial rotation with PMC disruption.

In conclusion, Svantesson et al ¹² are congratulated for their continuing efforts in bringing to the orthopaedic community the ongoing results from the largest ACL injury registry that exists. These data provide needed information in many categories related to ACL reconstruction, associated injuries, surgery, and postoperative success rates. It is not anticipated that the registry provides all of the information necessary for granular analysis of the data; however, the registry does have the ability to highlight problems needing future Level 1 studies. At the same time, the registry data have limitations where added data and clarity are necessary, which awaits future clinical research. RTS has too many variables that affect the final outcome and may have a limited basis for defining results of surgery, without a granular analysis to separate nonknee factors from knee-related factors. Even so, the goal remains for the return of sports at the chosen level of athletics with return of preinjury performance. It is also recognized that often these ACL injuries and associated concomitant injuries may require modification of sports and athletic expectations to allow a longer term participation in noninjurious athletic activities.