Summary of findings for the effects of knee arthroscopy versus control in patients with degenerative knee disease
| Outcome Timeframe | Study results and measurements | Absolute effect estimates | Certainty in effect estimates (Quality of evidence) | Summary | |
|---|---|---|---|---|---|
| Conservative management | Arthroscopy | ||||
| Short term | |||||
| Pain (difference in change from baseline) 3 months | Measured by: different instruments converted to scale of index instrument (KOOS pain subscale) Scale: 0–100 high better, minimally important difference 12) Data from 1231 patients in 10 studies Follow-up 3 months | 15.0 Points (mean) | 20.0 Points (mean) | High | On average, knee arthroscopy results in very small extra reduction in pain scores when compared with control |
| Difference: mean difference 5.4 more (95% CI 1.9 more—8.8 more) | |||||
| Pain (difference in patients who achieve a change higher than the MID) 3 months | Data from 1102 patients in 9 studies Follow-up 3 months | 669 Per 1000 | 793 Per 1000 | High | Knee arthroscopy increases the number of patients with an important reduction in short-term pain by ∼12 in 100 |
| Difference: 124 more per 1000 | |||||
| Function (difference in change from baseline) 3 months | Measured by: different instruments converted to scale of index instrument (KOOS ADL subscale, Scale: 0–100, high better minimally important difference 8) Based on data from 964 patients in 7 studies Follow-up 3 months | 9.0 Points (mean) | 14.0 Points (mean) | Moderate Owing to serious risk of bias, borderline inconsistency and borderline imprecision | Knee arthroscopy may increase function change slightly more than control |
| Difference: mean difference 4.9 more (95% CI 1.5 more—8.4 more) | |||||
| Function (difference in patients who achieve a change higher than the MID) 3 months | Based on data from 835 patients in 6 studies Follow-up 3 months | 519 Per 1000 | 653 Per 1000 | Moderate Owing to serious risk of bias | Knee arthroscopy probably increases the number of patients with an important improvement in short-term function ∼13 in 100 |
| Difference: 134 more per 1000 | |||||
| Quality of life (difference in change from baseline) 3 months | Measured by: EQ-5D VAS Scale: 0–100, high better minimally important difference 15 Based on data from 120 patients in one study Follow-up 3 months | 8.0 Points (mean) | 14.0 Points (mean) | Low Owing to serious risk of bias, owing to serious imprecision | Knee arthroscopy may have, on average, little or no difference on QoL change, compared with control |
| Difference: mean difference 6.0 greater (95% CI 1.5 fewer—13.5 more) | |||||
| Pain and function up to 3 months | Based on data from 316 patients in 3 studies Follow-up up to 3 months | Three studies evaluated the effects of knee arthroscopy in pain and function using measures that combined these two outcomes together or that could not be pooled. One study reported a difference in change from baseline in the Oxford knee score that favoured arthroscopy by 4.9 points (95% CI 3.61 to 6.20, 114 patients) over steroids injections. A second study reported no differences in the median in an overall self-assessment based on a 7-point ordinal scale (82 patients) when comparing knee arthroscopy to exercise therapy. The third study reported that patients who received intra-articular hyaluronic acid injections reported less pain than patients who received knee arthroscopy (120 patients) | Moderate Owing to serious risk of bias | Knee arthroscopy probably has little or no difference in pain and function when compared with control | |
| Long term | |||||
| Pain (difference in change from baseline) 1–2 years | Measured by: different instruments converted to scale of index instrument (KOOS pain subscale minimally important difference 12) Scale: 0–100, high better Based on data from 1097 patients in 8 studies Follow-up 2 years | 19.0 Points (mean) | 22.0 Points (mean) | High | On average, knee arthroscopy results in no difference or a very small reduction, in pain |
| Difference: mean difference 3.13 more (95% CI 0.17 fewer—6.43 more) | |||||
| Function (difference in change from baseline) 1–2 years | Measured by: different instruments converted to scale of index instrument (KOOS ADL subscale minimally important difference 8) Scale: 0–100, high better Based on data from 843 patients in 6 studies Follow-up 2 years | 10.0 Points (mean) | 13.0 Points (mean) | Moderate Owing to serious risk of bias and borderline imprecision | On average, knee arthroscopy probably does results in no improvement or a very small improvement, in function |
| Difference: mean difference 3.16 more (95% CI 0.48 less—6.8 more) | |||||
| Quality of life (difference in change from baseline) 1–2 years | Measured by: EQ-5D VAS, 15D (converted to EQ-5D scale, MID 15) Scale: 0–100, high better Based on data from 269 patients in 2 studies Follow-up 1 year | 10.3 Points (mean) | 12.4 Points (mean) | High | On average, knee arthroscopy does not result in an important improvement in quality of life |
| Difference: mean difference 2.12 more (95% CI 0.96 fewer—5.21 more) | |||||
| Knee replacement 1–2 years | Relative risk: 1.89 (95% CI 0.51 to 7.0) Based on data from 497 patients in 2 studies Follow-up 1 year | 12 Per 1000 | 23 Per 1000 | Moderate Owing to serious imprecision | On average, knee arthroscopy does not result in an increase in the risk of knee replacement |
| Difference: 11 more per 1000 (95% CI 107 more—6 fewer) | |||||
| Pain and function 1–2 years | Based on data from 114 patients in one study Follow-up 1 year | One study measured pain and function using a composite score. The study showed that patients who receive arthroscopy have a change in Oxford knee score 2.6 points higher than patients receiving steroids injections (95% CI 1.14 to 4.06) | Moderate Owing to serious risk of bias | Knee arthroscopy probably has little or no difference on pain and function | |
15D, the Health Related Quality of Life 15-Dimension questionnaire; ADL, Function in Daily Living; KOOS, Knee injury and Osteoarthritis Outcome Score; VAS, Visual Analogue Scale.