Table 1.
Characteristics of the studies included. Abbreviations: mo (months); MPFL (medial patellofemoral ligament), NR (not reported); SD (standard deviation), VM (vastus medialis); and y (years).
| Author (Publication Year) | Study Design | Country | Group Description | Type of Intervention | Follow-Up (Mean (SD), Range) | Number of Patients (Male/Female) | Age (Mean (SD), Range) | Number of Patients Who Completed the Follow-Up |
|---|---|---|---|---|---|---|---|---|
| Mikashima et al. (2004) [43] | Retrospective study | Japan | Intervention 1 group | Elmslie-Trillat distal realignment procedure | 41 (8.7) mo (range 28 to 52 mo) | 20 (5/15) with recurrent patellar dislocation and subluxation | 26.4 (9.7) y (range 14 to 45 y) | 20 |
| Intervention 2 group | Elmslie-Trillat distal realignment procedure + MPFL reconstruction | 31.7 (10.5) mo (range 24 to 44 mo) | 20 (6/14) with recurrent patellar dislocation and subluxation | 26.0 (10.0) y (range 16 to 55 y) | 20 | |||
| Woods et al. (2006) [48] | Case series (prospective cohort study) | USA | Intervention group (with contralateral limb as control) | Arthroscopic lateral retinacular release, including complete release of the vastus lateralis tendon | 27 mo (range 24–43 mo) | 24 (7/17) with recurrent patellar dislocation | 22.3 y; 26.2 (14.6) y (M); 20.7 (6.6) y (F) | 20 |
| Ronga et al. (2009) [44] | Case series (prospective cohort study) | Italy | Intervention group (with contralateral limb as control) | MPFL reconstruction using a hamstring graft passed through two transverse patellar tunnels | 37.2 mo (range 30–48 mo) [3.1 y (range, 2.5–4 y)] | 28 (21/7) with recurrent patellar dislocation | 32.5 (11.4) y; (range 19 to 40 y) | 24 |
| Smith et al. (2014) [45] | Observational, non-experimental repeated measures study | UK | Intervention | MPFL reconstruction | Up to 12 mo | 30 (16/14) with recurrent patellar dislocation | 23.1 (6.4) y | 30 at baseline, 27 at 1.5 mo, 21 at 3 mo, 21 at 12 mo |
| Tompkins et al. (2014) [47] | Retrospective study | USA | Intervention 1 group (with contralateral limb as control) | MPFL reconstruction | 29.2 (15.9) mo | 11 (NR) with recurrent patellar instability | 19.8 y | 8 patients (4/4, 1 bilateral), totaling 9 knees |
| Intervention 2 (with contralateral limb as control) | MPFL repair | 43 (19.9) mo | 29 (NR) with recurrent patellar instability | 20.1 y | 12 patients (3/9, 2 bilateral), totaling 14 knees | |||
| Smith et al. (2015) [46] | Pragmatic multi-center RCT | UK | Intervention 1 | Strengthening of VM | Up to 12 mo | 25 (14/11) with first-time patellar dislocation | 23.9 (7.5) | 16 at 1.5 mo, 10 at 6 mo, 10 at 12 mo |
| Intervention 2 (considered control in the study) | Strengthening of all quadriceps | Up to 12 mo | 25 (14/11) with first-time patellar dislocation | 23.0 (6.9) | 21 at 1.5 mo, 15 at 6 mo, 14 at 12 mo | |||
| Asaeda et al. (2016) [40] | Case series with matched controls (case-control study) | Japan | Intervention group | MPFL reconstruction | Up to 12 mo | 11 (3/8) with recurrent patellar dislocation | 21.2 (7.6) y, range 15 to 35 y | 11 pre-operation, 10 at 3 mo, 9 at 6 mo, 11 at 12 mo |
| Control group | Uninjured patients | Not applicable | 15 (NR) | 22.1 (1.8) y | Not applicable | |||
| Arrebola et al. (2019) [39] | Cross-sectional, case-control, observational study | Brazil | Intervention group | No intervention | Not applicable | 44 (14/30) with at least one episode of atraumatic patellar dislocation | 22 (8) y | Not applicable |
| Control group | Uninjured patients | Not applicable | 44 (11/33) | 21 (5) y | Not applicable | |||
| Keilani et al. (2019) [41] | Retrospective pilot study | Austria | Intervention 1 group | MPFL reconstruction | 47 mo | 6 (6/0) with recurrent patellar dislocation | 33 y (range 18 to 38 y) | 6 |
| Intervention 2 group | Elmslie-Trillat distal realignment procedure | 43 mo | 6 (6/0) with recurrent patellar dislocation | 26 y (range 19 to 32 y) | 6 | |||
| Lucas et al. (2020) [42] | Cross-sectional study | USA | Intervention group | No intervention | Not applicable | 16 (3/13) with recurrent patellar instability | 21.1 (4.2) y | Not applicable |
| Control group | Uninjured patients | Not applicable | 16 (3/13) | 21.1 (3.9) y | Not applicable |