Table 2 Biomechanical causations/relationships between LBP and knee OA

Huang et al, 2014 [18]

Pelvic anterior tilt(°): Greater in KOA compared to the healthy people (median (IQR),  with LBP  −44.68(−50.18/−40.52); NLBP  −45.83(−48.56/−39.38); healthy −32.61(−37.05/−28.47))

Anterior trunk inclination angle(°): no significant difference between KOA and healthy people (median(IQR),  with LBP  −82.13 (−89.33/−73.23); NLBP−83.96(−88.80/−74.07); controls −85.05(−85.96/81.92))

Trunk flexion angles(°): smaller in KOA patients compared to healthy people without KOA or LBP(median (IQR),  with LBP −27.65 (−33.07/−20.10) ; non LBP −27.44 (−32.83/−24.30); healthy −40.43 (−46.46/−36.44))

Trunk rotation angle(°): smaller in NLBP group than that of the controls (median (IQR),  with NLBP 6.01 (3.89/8.23); controls 9.15 (6.57/10.25)

Knee flexion angles in ipsilateral side of bending (°): significantly smaller  when doing the downward pick-up movement in both the LBP and NLBP groups (median (IQR),  with LBP −7.54 (−12.31/−3.78); non  LBP −6.39 (−12.95/−4.05); controls −19.89 (−31.63/−6.50))

Iwamura et al, 2020 [19]

Lumbo-pelvic sagittal alignment:development and progression of KOA in DS patients is induced by significantly greater mismatches of lumbo-pelvic sagittal alignment (p=0.02)

PI- significantly greater PI with  dominant of double adjacent level spondylolisthesis in patients with concurrent KOA (mean ± SD), (58.0° ± 10.4 ) and DS (p<0.01) than in patients with DS without KOA(52.8° ± 10.0) (p<0.01)

Not assessed

Parameters in lumbo-pelvic sagittal alignment: PT; LL; PI-LL and SS of KOA group and non-KOA group were mean ± SD,  27.2° ± 9.8 and 22.2° ± 8.6; 40.4° ± 15.8 and 42.6° ± 14.3;17.9° ± 15.1 and 10.3° ± 12.9, and 30.6° ± 10.0 and 30.6° ± 8.9, respectively, and significant difference was observed in the rate of double adjacent level spondylolisthesis (p = 0.023), and in the following sagittal parameters: PT (p < 0.001), and PI-LL (p < 0.001)

Kohno et al, 2020 [20]

PT(°): significantly greater in  patients with ASD ( mean ± SD), (26.2 ± 7.0)  in the severe-OA group than the patients without ASD (34.1 ± 10.8) (p=0.02)

PI, PT, KFA: significantly greater in severe OA group, than mild OA group along with a smaller degree of LL than the mild-OA group preoperatively (all p < 0.05)

KFA (°): significantly greater in severe OA (mean ± SD), (10.1 ± 5.3) group than the mild-OA (4.9 ± 6.8) group  pre- operatively (p=0.02)

LL(°): less in  patients with ASD ( mean ± SD), (34.9 ± 14.6), than without ASD  (40.6 ± 9.9) (p=0.26)

PI (°): significantly greater in severe OA group (mean ±SD), (7 ± 8.7) than the mild OA group (51.8 ± 9.6) (p= 0.05)

Rate of double-level listhesis:  significantly higher in the severe-OA group compared with the other groups (p=0.01) (patients number %) mild OA group 5 (12); moderate OA 8 (31); severe OA 16 (40)

PT (°): significantly greater in severe OA group (mean ± SD), (28.8 ± 9.3) than the mild OA group (20.1 ± 8.3) (p <0.01)

LL (°): significantly smaller in severe OA (mean ± SD), (38.7 ± 12.2) than the mild OA (45.6 ± 13.0) (p= 0.04)

Taniguchi et al, 2021 [23]

Lumbar kyphosis: associated with a lower functional abilities with lumbar kyphosis (mean± SD), (77.4 ± 19.1) (p < 0.001)  than those without lumbar kyphosis (86.1 ± 15.3) (p = 0.03)  

Not assessed

Not assessed

Van Erp et al, 2020 [16]

PT (p= 0.07) and SS (p=0.09): correlated with radiological  knee OA KL ≥ 2 and different degree of PI, individuals with high PI had significantly higher scores compared to low PI

PI: high PI (58.3) was associated with higher incidence of knee OA compared to low PI (49.5) (p = 0.03)

 Not assessed

Spondylolisthesis were more frequently present in subjects with high PI compared to low PI (L4 to L5; p = 0.02 vs L5 to S1; p = 0.001)

L5 to S1 DDD: occurred more in patients with low PI compared to high PI (p = 0.01)

Wang et al, 2016 [9]

Sagittal alignment: no significant difference between KOA patients with and without LBPComparable PI, SS, and PT values were revealed between the two groups, suggesting similar sagittal morphology and pelvic alignment

Patients with severe KOA showed significantly smaller SFA (43.1° versus 51.8°, p < 0.01) and PFA (2.2° versus 9.1°, p < 0.01) values compared with controls. 

Not assessed.

PI(°): with LBP (mean ± SD),(48.5±10.4), without LBP (45.0±10.0)(p=0.68)

FI: significant backward FI larger FI (11.3° versus 4.2°, p < 0.01), hip  flexion, and forward spinalinclination  in patients with severe KOA compared with  asymptomatic persons free from KOA (p < 0.01)

SS(°): with LBP (36.2±9.2) withoutLBP (32.9±8.4) (p=0.92)

FI  10°:  showed no significant difference in the prevalence of LBP compared with those with FI > 10° (18/23 versus 21/36 patients, chisquared = 2.5, p = 0.11)

PT(°):with LBP(12.5±6.3) withoutLBP(12.2±7.1) (p=0.32)

C7T: significantly smaller among severe KOA patients compared with controls (88.4° versus 92.9°, p <0.001), indicating forward inclination of the spine

Yasuda et al, 2020[22]

Lumbo-pelvic sagittal alignment: poor in individuals over 50 years of age with severe KOA and has stronger relationship with progression severity of KOA in women than in men   PT(°): (mean ± SD),  KL1(15.8±7.5),KL2(20.1±8.8), KL3(21.4±9.2),KL4(24.7±9.5) (p=<0.01)

Not assessed

Not assessed