Summary Table for Knee Function Measures*
| Scale | Purpose/content | Method of administration | Respondent burden | Administrative burden | Score interpretation | Reliability evidence | Validity evidence | Ability to detect change | Strengths | Cautions |
|---|---|---|---|---|---|---|---|---|---|---|
| Knee function | ||||||||||
| IKDC | Symptoms, sport/daily activities, function; variety of knee conditions | Patient completed | 10 min | 5 min; manual scoring using guidelines provided | Single score; 0–100 (100 = no symptoms, no limitation with daily/sport activities) | Internal: adequate; test–retest: adequate for groups/individuals with knee injuries | Face: adequate; content: cannot be assumed; construct: adequate | Responsive to change following surgery; MCID for cartilage repair, various knee surgeries | No floor/ceiling effects | No patient input in development; long recall period; missing data; lacking psycho- metric testing in knee OA; aggregate score may mask deficits in 1 domain; multiple versions available |
| KOOS | Pain, symptoms, ADL, sport/rec, QOL; posttraumatic knee OA and preceding conditions | Patient completed | 10 min | 5 min; scoring spreadsheet | 5 subscales; 0–100 (100 = no problems) | Internal, test–retest: variable (subscale, condition) | Face: adequate; content: adequate; construct: adequate | Responsive to change across a variety of knee conditions following surgical and nonsurgical interventions; MCID: NR | Substantial psychometric testing and cross-cultural validation; individual rather than aggregate scores | Not validated for interview administration; applicability of sport/rec items in older/less physically active patients |
| KOOS-PS | Function (ADL, sport/rec); knee OA | Patient completed | 2 min | <5 min; conversion table | Single score; 0–100 (100 = no difficulty) | Internal: adequate; test–retest: adequate for groups; less than adequate for individuals | Face: adequate; content: adequate; construct: adequate | Responsive to change following physical therapy and hyaluronic acid injection; MCID: NR | Developed using Rasch analysis; minimal burden | Psychometric testing only in knee OA |
| KOS-ADL | Symptoms, functional limitations; various knee pathologies (ligament/meniscal injuries, OA, PFP) | Patient completed | 5 min | <5 min; manual calculation | Single score; 0–100 (100 = no knee- related symptoms or functional limitations) | Internal: adequate; test–retest: adequate | Face: adequate; content: cannot be assumed; construct: adequate | Responsive to change across a variety of knee disorders and interventions (physical therapy, TKR); MCID for PFP | Reliable and valid | No patient input in development; descriptive responses may be confusing; ensure use of consistent version; may not be appropriate for highly active patients |
| Lysholm Knee Scoring Scale | Limp, support, locking, instability, pain, swelling, stairs, squatting; knee ligament surgery | In-person clinician administration | Variable depending on administration method | <5 min; manual calculation | Single score; 0–100 (100 = no symptoms or disability) | Internal: inadequate; test–retest: adequate only for groups with knee injuries | Face: adequate; content: cannot be assumed; construct: adequate | Responsive to change following surgery and PT; MCID: NR | Freely available; minimal burden | No patient input in development; risk of interviewer bias; multiple versions available |
| OKS | Pain, function; patients undergoing TKR | Patient completed | 5–10 min | <5 min; manual calculation | Single score; original version 12–60 (lower scores = better outcomes); modified version 0–48 (higher scores = better outcomes) | Internal: adequate; test–retest: adequate | Face: adequate; content: adequate; construct: adequate | Responsive to change following TKR; MCID: NR | Reliable, valid, and responsive for knee OA and TKR; cross- cultural validations | Some “double-barreled” items; use of aggregate score; beware of 2 different scoring methods |
| WOMAC | Pain, stiffness; function; knee and hip OA | Patient- or interview- administered questionnaire (validated for in-person, telephone, and electronic use) | 5–10 min | 5 min; manual or computer scoring | 3 subscales; range depends on version (Likert, VAS); lower scores indicate less pain, stiffness, and functional deficits | Internal: adequate for stiffness and function, variable for pain; test–retest: variable (subscale, condition) | Face: adequate; content: adequate; construct: adequate | Responsive to change following surgical and nonsurgical interventions for knee OA and chondral defects; MCID for TKR and NSAID use | Variety of validated administration methods; validated translations into multiple languages; individual subscale scores; minimal floor and ceiling effects | Licensing and fees required; applicability of function subscale items; redundant items in pain and function subscales (Rasch analysis) |
| Activity level | ||||||||||
| ARS | Athletic activities; various knee disorders; participation in sport | Patient completed | <5 min | 1 min; manual calculation | Single score; 0–16 (16 = more frequent participation) | Internal: NR; test–retest: adequate | Face: adequate; content: adequate; construct: adequate | Responsiveness, MCID: NR | Short and simple; adjunct to other knee function measures; generalizable across a variety of athletic and similar tasks | Recall difficulty; lack of psychometric testing |
| TAS | Level of sport and work participation; knee ligament injury (with Lysholm) | In-person clinician administration | 3.3 min | <1 min; score corresponds to single response selected | Single score; 0–10 (higher scores = participation in higher-level activities) | Internal: N/A; test–retest: adequate (groups), less than adequate (individuals) | Face: adequate; content: cannot be assumed; construct: adequate | Responsive to change following meniscal surgery and ACL reconstruction; MCID: NR | Simple; spans work and sport/rec activities | More suited to measure within-patient change; adjustment for age and sex |
*
IKDC = International Knee Documentation Committee Subjective Knee Evaluation Form; MCID = minimum clinically important difference; OA = osteoarthritis; KOOS = Knee Injury and Osteoarthritis Outcome Score; ADL = activities of daily living; sport/rec = sport/recreation; QOL = quality of life; NR = not reported; KOOS-PS = Knee Injury and Osteoarthritis Outcome Score Physical Function Scale; KOS-ADL = Knee Outcome Survey Activities of Daily Living Scale; PFP = patellofemoral pain; TKR = total knee replacement; PT = physical therapy; OKS = Oxford Knee Score; WOMAC = Western Ontario and McMaster Universities Osteoarthritis Index; VAS = visual analog scale; NSAID = nonsteroidal antiinflammatory drug; ARS = Activity Rating Scale; TAS = Tegner Activity Score; N/A = not applicable; ACL = anterior cruciate ligament.