Criterion‐based functional testing revealed maintenance of successful RTP criteria for 62/64 individuals. This resulted in the recommendation to discontinue brace use at this time interval, one year after ACLR. All patients were back to their premorbid level of function, after passing the RTS criteria on average of 6 months post‐operatively. All test trials compared the involved to the uninvolved, first in the braced condition and second in the un‐braced condition. The results demonstrated that the vast majority of patients one year after ACLR have the strength, confidence, and control of their knee to perform at least at an equivalent level as their uninjured lower extremity (LE). Overall, subjects were able to hop significantly farther and faster without a brace on their involved knee during all hop tests. All but one subject continued to score above the return to sport criteria at one year post‐op, and only two subjects did better braced than un‐braced.
Athletes were recommended to discontinue use of their brace because the brace could actually become a hindrance to their function, based on their test results. Reductions in strength and ROM have been noted in patients when wearing a functional brace in previous studies.15,16
This is even more of a concern when considering the patient who continues to wear a knee brace that may no longer be indicated. Risberg and colleagues have reported significant weakness in the quadriceps muscle in subjects who wore their functional braces for a period of time of greater than one year.17
Testing the patients at one year post‐op without a brace was the agreed upon time period amongst the clinical staff and the surgeon referring the patients, based upon a lack of consensus evidence to support earlier discontinuation, other than surgeon preference.5
By studying this group it was expected that the majority of the patients would be able to succeed without a brace one year after surgery, and hopefully prevent such complications that could arise related to quadriceps weakness.
The controversy regarding whether to use a functional brace post ACLR will continue as long as there are concerns about the strength of the graft and its' ability to withstand the stresses placed upon it during the first post‐operative year and as an athlete returns to high‐level sports. However, for those clinicians who brace their patients, the criterion provided by the authors could be used to objectively support clinical decisions for return to play with or without the brace at one year post‐op. If patients scored ≥ to 90% in the assessment of strength of the quadriceps compared to their uninvolved leg, on the KOS‐ADL score and GRS, and scored better in the 4 hop tests described by Noyes without their brace than with their brace, then the athlete was considered ready to discontinue the use of a functional brace for high‐level activity.
Successful completion of these proposed criterion can assist physicians and physical therapists performing pre‐employment screens, evaluating patients whose brace no longer fits or is damaged, and in trying to answer the patient's question as to when they can discontinue using it.
Limitations of this study include a possible order effect and the lack of a randomized control group. The order of the testing was always two practice trials followed by two testing trials with the uninvolved leg tested first and the braced condition being performed prior to the un‐braced condition. The concern regarding this sequence is the potential for increase in confidence and possible physiologic changes may occur with increased activity, which may have played a role in the outcomes of the study. There is also the issue that a hop test with and without the brace was not performed any earlier than one year post‐op. Therefore, the authors do not know if subjects could have succeeded in passing the criterion at an earlier point in time. It was determined during this study that there would have been benefit to collecting qualitative data about which patients had actually been compliant (and to what level) with wearing their brace during sports activities between their testing sessions. Not having this data is a limitation in understanding why patients may have done better without their brace at the 1‐year postoperative testing period.
No subjects injured their involved knee while testing without the brace. Based on these results, the authors recommend further research on 1) whether or not patients can safely return to sport without their brace earlier than one year post‐op, and 2) patient compliance with brace wear during the time when they are supposed to be utilizing it. There is no consensus as to when the graft is equivalent to the normal ACL with regard to stress to ultimate failure and linear stiffness. A case study by Beynnon and colleagues suggests load to ultimate failure and linear stiffness approaches that of the contralateral ACL by 8 months post‐op.18
The next step could be to look at what time after surgery it is possible for patients to pass the return to sports criteria without their brace. Other research could consider whether there are additional factors that need to be evaluated for criterion for RTS without a brace, such as if the sport is a high impact/contact activity.