Table 1.
Baseline characteristics of the intention-to-treat population
| APM group | PT group | |
| Demographics | N=158 | N=161 |
| Age, years | 57.6±6.5 | 57.3±6.8 |
| Women | 80 (50.6) | 81 (50.3) |
| Right knee | 88 (55.7) | 81 (50.3) |
| Education level, beyond high school | 67 (42.4) | 86 (53.4) |
| BMI (kg/m2) | 26.7±3.8 | 27.2±4.0 |
| 18.5<BMI<25 | 56 (35.4) | 53 (32.9) |
| 25≤BMI< 30 | 72 (45.6) | 67 (41.6) |
| 30≤BMI< 35 | 30 (19.0) | 41 (25.5) |
| Mechanical complaints* | 56 (35.4) | 67 (41.6) |
| Imaging† | ||
| Affected meniscus | N=158 | N=161 |
| Medial | 126 (79.7) | 136 (84.5) |
| Lateral | 30 (19.0) | 25 (15.5) |
| Both | 2 (1.3) | 0 (0) |
| Type of tear on MRI42 | N=151 | N=152 |
| Longitudinal vertical | 5 (3.3) | 5 (3.3) |
| Horizontal | 80 (53.0) | 69 (45.4) |
| Complex degenerative | 47 (31.1) | 58 (38.1) |
| Radial | 13 (8.6) | 10 (6.6) |
| Vertical flap | 2 (1.3) | 5 (3.3) |
| Unclassifiable | 1 (0.7) | 5 (3.3) |
| Horizontal flap | 3 (2.0) | 0 (0) |
| OA level‡ | N=150 | N=149 |
| 0: None OA | 18 (12.0) | 15 (10.1) |
| 1: Doubtful | 81 (54.0) | 74 (49.7) |
| 2: Minimal | 45 (30.0) | 55 (36.9) |
| 3: Moderate | 6 (4.0) | 5 (3.3) |
| Knee function | N=158 | N=161 |
| IKDC score (0–100, worse to best) | 44.8±16.6 | 46.5±14.6 |
| EQ-5D-5L Index value | 0.72±0.2 | 0.74±0.1 |
| N=146 | N=158 | |
| EQ-5D-5L Quality of life scale | 74.9±18.4 | 73.6±19.5 |
Data are n (%) or mean±SD.
*In contrast to locking of the knee joint, which was an exclusion criterion, mechanical complaints were allowed for inclusion.
†Although inclusion was based on clinical readings by different radiologists and orthopaedic surgeons, one radiologist read all radiographs post hoc and one radiologist read all MRIs post hoc. Some of the radiographs (6.3%) and MRIs (5.0%) were unavailable to the viewing radiologist.
‡Kellgren-Lawrence grade 0 (no osteophytes or joint-space narrowing) indicates no osteoarthritis, grade 1 (questionable osteophytes) indicates early onset osteoarthritis, grade 2 (definite osteophytes, no joint-space narrowing) indicates mild osteoarthritis, grade 3 (50% joint-space narrowing) indicates moderate osteoarthritis, and grade 4 (>50% jointspace narrowing) indicates severe osteoarthritis.7 Kellgren-Lawrence grade 4 was an exclusion criterion.
APM, arthroscopic partial meniscectomy; BMI, body mass index; EQ-5D-5L, EuroQol five-dimensional five-level questionnaire; IKDC, International Knee Documentation Committee; ISAKOS, International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine; KL, Kellgren-Lawrence classification; MRI, magnetic resonance imaging; N, number; OA, osteoarthritis; PT, physical therapy.