INTRODUCTION

This chapter reviews commonly used scales and outcome instruments that rate athletic and daily functional activities for a variety of knee injuries and disorders. The subjects in the investigations typically represent young active patients, with the majority treated for anterior cruciate ligament (ACL) ruptures. The instruments are analyzed according to their strengths and potential biases as well as reliability, validity, and responsiveness test findings.

Outcome measures are available for older or sedentary populations with osteoarthritis such as the Western Ontario and MacMaster Universities (WOMAC),¹ the Knee Pain Scale,¹⁸ and the Knee Society Clinical Rating System.⁸ There are also several generic health status instruments, such as the Medical Outcomes Study Short Form-36 Health Survey (SF-36) and the Medical Outcomes Study Short Form-12 (SF-12). It is not the purpose of this chapter to review these instruments. Scales from the Cincinnati Knee Rating System (CKRS) and the International Documentations Committee Rating System are not included, because they are described in detail in Chapters 44 and 45, respectively.

It is important to stress that, in the authors’ opinion, knee rating systems must measure not only symptoms and athletic and daily functional activities but objective physical findings as well. The assessment of patient outcome using subjective questionnaire data only does not provide an accurate understanding of the ability of the treatment protocol to restore normal knee function. Factors such as range of knee motion, joint effusion, tibiofemoral and patellofemoral crepitus, knee ligament subluxations, radiographic findings, and limb symmetry on functional testing should all be included in clinical investigations.

SPORTS ACTIVITY SCALES

7 Competitive sports   Recreational sports 6 Recreational sports 5 Work Heavy labor (e.g., building, forestry)   Competitive sports Cycling     Cross-country skiing   Recreational sports Jogging on uneven ground at least twice/wk 4 Work Moderately heavy labor (e.g., truck driving, heavy domestic work)   Recreational sports 3 2 Light labor 1 Sedentary work 0 Sick leave or disability pension because of knee problems  

From Tegner, Y.; Lysholm, J.: Rating systems in the evaluation of knee ligament injuries. Clin Orthop Relat Res 198:43–49, 1985.

Several problems are incurred with this activity rating instrument. First, work activities are rated within the same scale as sports activities. Patients who work in heavy-labor occupations are awarded only a level 5 (out of a possible 10), but the analysis of the stress on the lower limb in some of these occupations would probably show that these knees are functioning at a level equivalent to that of competitive athletes. They should not be awarded a lower level simply because they are not athletes or did not return to highly competitive sports. Athletics and occupational activities should be measured on separate rating scales (see Chapter 44).

Second, this scale does not separate various sports levels according to frequency of participation or the intensity of the sport, which is determined by accounting for the forces placed on the lower extremity. For instance, only national and international elite soccer players are listed on level 10, whereas basketball is listed on a level 7. In the United States, it could be argued that competitive high school, collegiate, or professional basketball players are asked to place similar demands on the knee joint and lower extremity as elite soccer players. For patients who play or return to sports not listed on the scale, problems are incurred in trying to determine exactly which level accurately defines their sport. Third, this scale does not allow an assessment of a change in athletic participation between time periods owing to a change in lifestyle (e.g., graduated from school and no longer participate in a league). In addition, one cannot detect knee abusers in either the sport or the work levels.

Two independent investigations assessed the reliability, validity, and responsiveness of the Tegner scale. Briggs and coworkers³ determined its reliability, validity, and responsiveness in 122 patients with meniscus injuries. The scale was found to have adequate reliability (intraclass correlation coefficient [ICC], 0.817), content validity (no ceiling or floor effects), criterion validity with the generic SF-12 scale, and construct validity. However, only moderate effect sizes and standardized response mean values were reported. The investigators concluded that the scale measures only moderate changes in activity levels and noted that patients in the United States may have difficultly completing the scale because it was designed for sports commonly played in Europe. Paxton and associates¹⁷ assessed the reliability and validity of this scale in 153 patients followed 2 to 5 years after an acute patellar dislocation. The scale was found to have adequate reliability (ICC, 0.92) and content validity.

Modified Hospital for Special Surgery Sports Scale

The modified Hospital for Special Surgery (HSS) knee assessment instrument (see Table 46-2) was developed for an investigation of 48 patients with ACL-deficient knees who underwent arthroscopic partial meniscectomy.⁶ The instrument includes a scale composed of four levels of various sports ranked “very stressful,” “moderately stressful,” “mildly stressful,” and “no sports activities.” Examples of sports are provided in categories A, B, and C to assist with the ratings. The advantages of this scale include the assessment of sports activities only (separately from occupations) and the attempt to sort sports participation according to the level of intensity. The problems with this scale are that ambiguous terms are used to rate the sports categories (as “very stressful” may have different meanings to different patients), an assessment of reasons for change in athletics owing to non–knee-related reasons is not provided, and the detection of knee abusers is not possible. The authors did not conduct reliability, validity, or responsiveness testing of their outcome instrument.

Seto Sports Participation Survey

Seto and colleagues²⁴ developed a sports participation survey in order to determine activity levels in 19 patients who had undergone ACL reconstruction. In this survey, subjects rated their activity level for 13 sports, which are divided into cutting and noncutting categories. Each sports activity receives 0 to 4 points, based on the ability to participate with no symptoms (4 points), participate with “recurring mild episodes of pain, swelling, or instability” (3 points), limited participation owing to “moderate or severe episodes of pain, swelling, or instability” (2 points), or not able to participate owing to either knee-related (1 point) or non–knee-related (0 points) reasons.