Table 2 The occurrence and clinical effects of FTE following MPFLR
Study | Criteria for FTE | FTE | Clinical effect of FTE |
|---|---|---|---|
Turgay et al., 2017 | Not reported | 12 (38.7%) patients experienced femoral tunnel enlargement, and 75% of these patients had proximal tunnel misplacement. Of the 19 (61.3%) patients without femoral tunnel expansion, only 32% had proximal tunnel misplacement | There were no differences in Tegner, Kujala, and IKDC scores in patients with and without femoral tunnel enlargement |
Schüttler et al., 2018 | Increase to more than double of the femoral tunnel’s original area in at least two of its sections | A total of 23 (45.1%) knees experienced FTE | Patients with FTE displayed significantly better outcomes in terms of symptoms and performance of daily activities according to the Kujala (84 vs. 75, p = 0.032) and IKDC (80 vs. 71, p = 0.024) scores, but not as measured with the Tegner score (4.2 vs 3.9) |
Berard et al., 2013 | Increase to more than double of the femoral tunnel’s original area | Of the 55 patients, 23 (41.8%) experienced FTE The mean cross-sectional area of the tunnel in the non-enlarged group was 57.9 mm2, compared with 105 mm2 in the enlarged group (P < .001) | IKDC scores did not differ between patients with and without FTE (82.6 vs 83.0, respectively, p = 0.93). There was no difference in risk of patellar instability between both groups (p = 1.0) |
Neri et al., 2019 | Percentage increase in tunnel cross-sectional area from baseline was calculated | Number of patients experiencing FTE were not reported. Degree of FTE was not reported. Malposition of the femoral tunnel was correlated with FTE | FTE predicted lower functional scores. Increases in femoral tunnel area at 5 mm, 15 mm, and 25 mm from the medial femoral cortex were negatively associated with post-operative Kujala and IKDC scores (− 0.535 and − 0.557, − 0.331 and − 0.296, − 0.218 and − 0.193, respectively) |
Kita et al., 2017 | Percentage increase in the aperture and inside the tunnel cross-sectional area from baseline was calculated | Cross sectional area at the aperture increased from 21.7 mm2 at 3 weeks to 30.3 mm2 1-year post-op (41.1% increase, p > 0.05). Area 5 mm from the aperture increased from 21.9 to 23.8 mm2 (8.8% increase, p > 0.05), and area 10 mm from the aperture increased from 22.1 to 22.7 mm2 (2.6% increase, p > 0.05) | Femoral tunnel enlargement was not associated with post-operative Kujala scores (r = − 0.015, p = 0.946) |
Wong et al., 2021 | Calculated by subtracting the size of the screw used from the measured opening tunnel size | Mean increase in femoral tunnel size was 2.5 mm | Not reported |
Qin et al., 2017 | Increase in femoral tunnel width at 3 days and last follow-up was measured | At the last follow-up, there were 54 knees with tunnel enlargement (77.1%), and 16 without (22.9%). Femoral tunnel width was 8.7 mm at 3 days, and 10.6 mm at last follow-up. There was a 21.8% increase (p < 0.05) | Average Kujala score was 82.5 in patients with FTE, compared to 79.4 in those without (p = 0.386). Lysholm score was 84.8 in patients with FTE, compared to 78.6 in those without (p = 0.085) |