Prospective Evaluation of the Patient Acceptable Symptom State to Identify Clinically Successful Anterior Cruciate Ligament Reconstruction

Vega JF, Jacobs CA, Strnad GJ, Farrow L, Jones MH, Miniaci A, Parker RD, Rosneck J, Saluan P, Williams JS, Spindler KP. Am J Sports Med. 2019 [Epub ahead of print]

Take Home Message: A single Patient Acceptable Symptom State question may be enough to identify a patient who views their knee recovery as unsuccessful after an anterior cruciate ligament reconstruction.

Many clinicians omit patient-reported outcome measures during evaluations because they are at least in part to time consuming. For example, the Knee Injury and Osteoarthritis Outcome Score (KOOS), which is commonly used following an anterior cruciate ligament reconstruction to measure a patient’s view of their recovery, has over 40 questions. One way to reduce the burden on a patient is to use a single-item, patient-reported outcome measure such as the Patient Acceptable Symptom State (PASS). However, there has been no research to determine if a PASS question could be a surrogate for a lengthier joint-specific patient-reported outcome measure. Hence, the authors conducted a cohort study to determine if the response to a PASS question would relate to a successful outcome 1 year after an anterior cruciate ligament reconstruction. The authors defined a successful outcome based on two methods: 1) a patient’s change in KOOS pain or knee-related quality of life scores exceeded a previously defined clinically important difference, or 2) their final KOOS pain or knee-related quality of life scores exceeded previously defined patient acceptable thresholds. The authors enrolled 555 patients who underwent an anterior cruciate ligament reconstruction between February 2015 and June 2016 at 3 centers. Out of the 464 participants eligible for this study, only 299 participants (53% female, ~26 years of age) completed the KOOS right before surgery and at one year after surgery. Also, at the one-year follow-up assessment patients answered the PASS question: “Taking into account all the activity you have during your daily life, your level of pain, and also your activity limitations and participation restrictions, do you consider the current state of your knee satisfactory?” Patients answered either “yes” or “no.” The majority of patients were satisfied with the anterior cruciate ligament reconstruction at 1-year follow-up (83% answered yes to PASS). Additionally, most reached a successful outcome (77%) with a score of > 62.5 for the KOOS quality of life subscale and a score of > 88.9 for the KOOS pain subscale. Lastly, the PASS demonstrated high sensitivity (93%), but poor specificity (47%). The overall
agreement between the KOOS-based successful outcome and PASS acceptable outcome was moderate (82% agreement).

The authors found that a “yes” to the PASS question was able to identify patients that feel they had positive outcomes following surgery based on the KOOS. Due to the low false negative value of the PASS question, it can be useful in identifying patients that failed to benefit from surgery. This would allow medical professionals to then intervene with additional methods to enhance patient outcomes. However, the PASS question demonstrated low specificity. Patients who did not report clinically successful scores following an anterior cruciate ligament reconstruction on the KOOS subscales still reported being satisfied with their knee. This may be due to the patients experiencing improvements in other aspects of their health that the authors never measured. While these results remind clinicians of the value of single-item assessments we should also acknowledge that many people failed to complete the study and it is unclear if people who never attended follow-up were more likely to have less optimal outcomes. Furthermore, some of the KOOS thresholds are based on how they relate to a single-item assessment. Hence, it may not be surprising that the PASS question performed well. Finally, it may have been helpful if the authors used multiple patient-reported outcome measures to define post-surgical success. Despite these limitations, clinicians may find the PASS question helpful for determining if a patient is satisfied with their knee and to identify patients who may need additional screening or treatment.

Questions for Discussion: How do you measure ACLR outcomes? Do you use PROMs? If so, is the PASS question on of the PROMS you use? If not, would you consider incorporating it into practice?

Written by: Jane McDevitt

Reviewed by: Jeffrey Driban

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