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Table 2 Comparison between “non-failed” and “failed PFA”

From: Preoperative patellofemoral anatomy affects failure rate after isolated patellofemoral inlay arthroplasty

Variable Group p value
Non-failed Failed
Gender    0.517
 Female 17 (65%) 8 (53%)
 Male 9 (35%) 7 (47%)
Age (years) 45.0 ± 13.1 53.5 ± 10.5 0.038a
BMI (kg/m2) 25.7 ± 3.6 26.8 ± 3.3 0.362
Tibiofemoral OA (Kellgren–Lawrence)    0.318
 None or Grade I 15 (63%) 6 (43%)
 Grade II, III, or IV 9 (38%) 8 (57%)
Patellofemoral OA (Iwano)    1.000
 None or Grade I 8 (35%) 5 (39%)
 Grade II, III, or IV 15 (65%) 8 (62%)
Insall–Salvati Index 1.1 ± 0.2 1.4 ± 0.2 < 0.001a
Insall–Salvati Index    0.008a
 ≤ 1.2 18 (75%) 4 (29%)  
 > 1.2 6 (25%) 10 (71%)
Patellotrochlear Index 0.5 ± 0.19 0.37 ± 0.18 0.038a
Patellotrochlear Index    0.002a
 ≥ 0.28 23 (92%) 7 (47%)
 < 0.28 2 (8%) 8 (53%)
TT–TG distance (mm) 11.3 ± 3.9 13.6 ± 3.4 0.065
TT–PCL distance (mm) 19.9 ± 5.8 22.9 ± 4.0 0.092
TT–PCL distance    0.156
 ≤ 21 mm 13 (52%) 4 (29%)
 > 21 mm 12 (48%) 10 (71%)
Trochlear dysplasia (Dejour)    0.010a
 Normal 7 (27%) 12 (80%)
 Type A 7 (27%) 0 (0%)
 Type B 7 (27%) 1 (7%)
 Type C 4 (15%) 2 (13%)
 Type D 1 (4%) 0 (0%)
Trochlear dysplasia (Dejour)    0.001a
 Normal 7 (27%) 12 (80%)
 Types A–D 19 (73%) 3 (20%)
  1. The group “failed” consisted of patients converted to TKA during the study period or not achieving minimal clinically important difference (MCID) for WOMAC total or VAS pain at 24 months
  2. Continuous variables are shown as mean ± standard deviation, categorical variables are shown as number of patients and percentages per group
  3. OA osteoarthritis, TT–TG tibial tuberosity trochlear groove, TT–PCL tibial tuberosity posterior cruciate ligament, mm millimeters, kg kilograms, kg/m2 kilograms per square meter
  4. aStatistically significant difference between both groups