Baseline characteristics of the participants allocated to APM or placebo surgery. Values are numbers (percentages), means±SD or medians (ranges)
| APM (n=70) | Placebo surgery (n=76) | |
| Sex | ||
| Female | 28 (40) | 29 (38) |
| Male | 42 (60) | 47 (62) |
| Age (years) | 52.1±6.9 | 52.0±7.2 |
| Body mass index (kg/m2) | 26.9±4.0 | 27.9±4.0 |
| Duration of symptoms (months) | 10 (3–50) | 10 (3–47) |
| Kellgren-Lawrence grade* | ||
| 0 | 35 (50) | 36 (47) |
| 1 | 35 (50) | 40 (53) |
| Meniscal tests | ||
| Positive McMurray test† | 16 (23) | 15 (20) |
| Pain provoked by forced flexion and compression | 50 (71) | 59 (78) |
| Pain provoked by palpation at the joint line | 63 (90) | 74 (97) |
| Symptoms of catching or locking | 32 (46) | 37 (49) |
| Unstable tear at knee arthroscopy‡ | 34 (49) | 41 (54) |
| WOMET score§ | 56.4±17.3 | 52.8±18.1 |
| Lysholm score¶ | 60.2±14.7 | 60.1±14.6 |
| Pain after exercise (VAS)** | 5.8±2.0 | 6.1±2.0 |
*The Kellgren-Lawrence scale is a radiographic classification of the severity of knee osteoarthritis. Grade 0 denotes no abnormalities and grade 1 denotes minor degenerative changes (doubtful narrowing of the joint space or possible osteophytic lipping).
†Results of a McMurray test are positive if a ‘click’ over the medial tibiofemoral joint line is felt by the examiner during flexion and extension of the knee under varus stress.
‡Longitudinal, bucket handle or flap tear at arthroscopy.
§The WOMET contains 16 items addressing three domains: 9 items addressing physical symptoms; 4 items addressing disabilities with regard to sports, recreation, work and lifestyle and 3 items addressing emotions. The score indicates the percentage of a normal score; therefore, 100 is the best possible score and 0 is the worst possible score.
¶The Lysholm knee score is based on an eight-item questionnaire designed to evaluate knee function and symptoms in activities of daily living. Scores range from 0 to 100; higher scores indicate less severe symptoms.
**Knee pain after exercise (during the preceding week) was assessed on a rating scale of 0–10, with 0 denoting no pain and 10 denoting extreme pain.
APM, arthroscopic partial meniscectomy; WOMET, Western Ontario Meniscal Evaluation Tool; VAS, visual analogue scale.