MARX Knee Score
MARX was developed in 2001 as a patient-reported outcome measure with the goal of finding a patient’s general level of activity. MARX focuses on four activity points: running, deceleration, cutting (changing directions while running), and pivoting. Patients are asked to indicate approximately how many times in the past 12 months they performed each of these activities while at their healthiest and most active state. The four knee functions are rated on a 5-point scale of frequency and scores are added up to a maximum of 16 points with a higher score indicating more frequent participation.
The MARX rating scale is different from most previous measures of activity because it’s not based on participation in specific sporting activities. Instead, patients are asked about different components of physical function (e.g. running and pivoting) that are common to different sports.
The key strength of the MARX activity rating scale is that it may be self-administered and takes approximately one minute to complete. The measure also asks patients about issues that are speciﬁcally relevant to them, such as giving way, pain, locking of the knee, and ability to run. In addition, studies have shown that there’s a moderate correlation between the MARX and the Tegner Activity Scale (TAS).
There is a concern that the MARX rating scale does not adequately differentiate between patients that remain active in non-knee aggravating activities and those that give up sports entirely, creating a possible floor effect that requires investigation.
Additionally, despite rigorous development processes, more studies need to be carried out highlighting the psychometric evidence for the MARX scale which should include a comprehensive analysis of clinical usefulness, reliability, validity, and responsiveness.
The MARX PRO Measure does not require a license and is free to use.
Citation: Assessing activity participation in the ACL injured population: a systematic review of activity rating scale measurement properties. Robert Letchford, Kate Button, Valerie Sparkes, and Robert W M van Deursen. Physical Therapy Reviews 2012 17:2, 99-109
Citation: Marx, R. G., Stump, T. J., Jones, E. C., Wickiewicz, T. L., & Warren, R. F. (2001). Development and evaluation of an activity rating scale for disorders of the knee. The American journal of sports medicine, 29(2), 213-218.
Citation: Kanakamedala, A. C., Anderson, A. F., & Irrgang, J. J. (2016). IKDC Subjective Knee Form and Marx Activity Rating Scale are suitable to evaluate all orthopaedic sports medicine knee conditions: a systematic review. Journal of ISAKOS: Joint Disorders & Orthopaedic Sports Medicine. Accessed January 27, 2016.
Citation: Negahban H, Mostafaee N, Sohani SM, Mazaheri M, Goharpey S, Salavati M, et al. Reliability and validity of the Tegner and Marx activity rating scales in Iranian patients with anterior cruciate ligament injury. Disabil Rehabil Assist Technol. 2011;33(22–23):2305–10. doi: 10.3109/09638288.2011.570409