Table 3

Outcome measures of SRS that addressed total knee arthroplasty

Functional outcomes of SRs that addressed TKA
Knee Society Scores (KSS)
SRResults
Xie, 2012Within 6 months: mean standard difference: 4.47; (95% CI 21.05 to 9.99, p=0.36)
Cheng, 2012At 3 months (WMD=1.11, 95% CI −6.33 to 8.56) and 6 months (WMD=2.13, 95% CI −2.53 to 6.79) follow-up
Rebal, 20143 months postoperative change: CA TKA had a mean score increase of 68.5 (52.9–75.0), significantly superior to the mean score of 58.1 (47.3–64.0) for knees performed with conventional guides (p=0.03, 95% CI 1.13 to 19.78)
Postoperative change at 12–32 months follow-up: knees in the CA TKA groups improved by a mean of 53.1 (37.7–96.6), significantly superior to the mean of 45.8 (32–89.5) for the CONV group (p<0.01, 95% CI 2.87 to 11.90)
Shin, 2016The pooled data showed that the mean difference in the postoperative KSS was 11.15 points higher with the MINA approach than the CONV approach, but this difference was not statistically significant (95 % CI −8.55 to 30.84; N.S.; I 2=98%
VanderList, 20166 months: pooled mean difference=5.2 (3.41, 7.00). 1 year: (8.46, 90.65, 16.28). 2 years: 1.97 (−1.91, 5.84). More than 4 years: 2.65 (0.84, 4.46). Total=2.86 (0.96, 4.76)
Navigated vs conventional TKA surgery with navigation systems aiming to control for alignment and component position: pooled mean difference=0.66 (−2.06 to 3.38)
Navigated vs conventional TKA surgery with navigation systems aiming to control for alignment and component position with controlling for soft tissue balance: pooled mean difference=4.84 (1.61 to 8.07)
Moskal, 2014KSS were slightly larger for NAV, demonstrating some improvement compared with CONV.
Knee Society Function Scores: standardized difference in means=−0.341 95% CI (−0.532 to −0.150) p=0.000
Knee Society Knee Scores: standardized difference in means=−0.294 95% CI (−0.489 to −0.100) p=0.003
Knee Society total Scores: standardized difference in means=−0.623 95% CI (−0.940 to −0.307) p=0.000
Panjwani, 2019Follow-up ≥ 2 years and <5 years postoperatively: no difference (p=0.13; pooled mean difference=−0.86; CI −1.96 to 0.25)
Follow-up >5 years and <8 years postoperatively: no significant difference in the two groups (p=0.09)
Follow-up >8 years postoperatively: no significant difference in the two groups (p=0.91)
WOMAC Scores
Moskal 2014WOMAC Scores (Pain Score, Stiffness Score, and Physical Function Score) were slightly lower for NAV, showing some improvement compared with CONV.
WOMAC Pain Scores: standardized difference in means=−0.472; 95% CI (−0.826 to −0.117), p<0.009
WOMAC Stiffness Scores: standardized difference in means=−0.274 95% CI (−0.538 to −0.010), p<0.042
WOMAC Physical Function Scores: standardized difference in means=−0.369 95% CI (−0.619 to −0.173), p<0.001
Panjwani, 2019Follow-up ≥2 years and <5 years postoperatively: no difference between the two groups (p=0.60; pooled mean difference=0.86; CI −2.32 to 4.04)
Follow-up >5 years and <8 years postoperatively: significantly better in the CAS-TKA group (p<0.0001; pooled mean difference=−2.05; CI −2.82 to −1.28)
Follow-up >8 years postoperatively: no difference in the two groups (p=0.94; pooled mean difference= −0.08; CI −2.10 to 1.95)
Karunaratne, 2019Low quality of evidence of no difference (mean difference= −0.51; 95% CI −1.95 to 0.94)
Knee range of motion (ROM)
Xie, 2012Mean standard difference: 1.38; 95% CI 21.43 to 4.18, p=0.34)
Shin 2016The pooled mean difference in postoperative flexion ROM was 16.64 (95 % CI 14.26 to 19.01, p<0.001; I2=0%)
Hospital for special surgery (HSS)
Karunaratne, 2019Medium-term: low quality of evidence of no difference between groups (mean difference=0.04 (−2.94 to 3.01))
Long-term: low quality of evidence of no difference between groups (mean difference=−0.51 (−1.83 to 0.82))
Radiological outcomes of SRs that addressed TKA
Mechanical axis malalignment
Smith, 2012No difference
Hetaimish, 2012Malalignment >3°: RR=0.37 (95% CI 0.24 to 0.58, p=0.00001), MAM>2°: 0.54 (95% CI 0.42 to 0.69, p=0.004)
Thieopont, 2013Malalignment >2°, the effect measures (ie, OR and risk ratio) ranged from 0.21 to 0.76
Malalignment >3°, the reduction was comparable, and effect measures ranged from 0.19 to 0.79
Cheng, 2012Mechanical axis malalignment >3°: OR=0.4 (95% CI (0.31 to 0.51)
Fu, 2012Malalignment of >3°: a meta-analysis OR of 0.26 (95% CI 0.17 to 0.38)
Malalignment at >2°: a meta-analysis OR of 0.33 (95% CI 0.26 to 0.42)
Rebal, 2014The risk difference of alignment within 3° of ideal is 0.14 (CI 0.1 to 1.18)
The absolute value of degrees deviation: for the CAS group the mean deviation was 1.3° (1.0° to 1.9°), significantly less than the CONV group deviation of 2.4° (1.8° to 3.2°) (P < .01, 95% CI −1.38 to −0.67
The mean average of the degrees of deviation of the mechanical axis: The CAS group had a mean deviation of 0.3° (−0.6° to 1.0°) while the CONV group had a mean deviation of 0.5° (−2.4° to 1.2) (p=0.33, 95% CI −0.65 to 0.22)
Note: positive values for varus deviation and negative values for valgus deviation
Shi, 2014 The pooled OR for overall outliers in mechanical axis showed no difference between the two groups; no heterogeneity was observed (p=1.000; I2=0.0%)
Shin 2016No statistical difference is present (95 % CI 1.01 to 0.54; N.S.; I2=64%)
Zamora, 2013OR of postoperative alignment of the mechanical axis in the frontal plane (postoperative deviation of 3° from target angle of 180°=2.32. (95% CI 1.77 to 3.04)
Cheng, 2011 (A)RR=0.4; 95% CI 0.31 to 0.5
Mason, 2007Malalignment >3 °: a meta-analytic mean OR 0.22 (95% CI 0.16 to 0.29)
Malalignment >2 °: a meta-analytic mean OR of 0.35 (95% CI 0.28 to 0.43)
Cheng, 2011 (B)Malalignment >3° (RR=0.19, 95% CI 0.11 to 0.32, p<0.00001, I2=10%
Liu, 2014Malalignment >3°(OR=0.55; 95% CI 0.44 to 0.68, p<0.001)
Brin, 2011Malalignment >3°: (prospective randomized studies alone): OR=0.03 (95% CI 0.15 to 0.52),
(prospective randomized and retrospective studies): OR=0.21 (95% CI 0.12 to 0.33)
Moskal, 2014Femoral flexion angle deviation from neutral: standardized difference in means: −0.606. 95% CI −0.856 to −0.356, p=0.000
Anatomic axis outliers: standardized difference in means: 0.242; 95% CI 0.098 to 0.593, p=0.002
Mechanical axis outliers: OR=0.356; 95% CI 0.237 to 0.536, p=0.000
Tibial component alignment outliers: OR= 0.356; 95% CI 0.237 to 0.536,) p =0.000
Femoral component alignment outliers: OR=0.387; 95% CI 0.254 to 0.589, p=0.000
Mannan, 2018Weighted mean differences of postoperative alignment to be more accurate in the robotic knee group: mean difference=−0.63; 95% CI −1.18 to 0.08, z=2.25, p=0.02
Coronal plane femoral component outliers
Fu, 2012The OR of malalignment of >3° was estimated at 0.33 (95% CI 0.14 to 0.75)
Rebal 2014Within 3° of ideal (90°): 97.6% (94%–100%) in the CAS groups, significantly more than the 87.4% (81%–97%) in the CONV group (P b .01, 95% CI 0.05 to 0.14)
Shi 2014The pooled data in the random-effects model showed no difference between the two groups. No heterogeneity was observed
Shin 2016The pooled mean difference was similar between the MINA and CONV approaches (95 % CI −0.91 to 2.97; N.S.; I2=95%)
Cheng 2011 (A)RR=0.37; 95% CI 0.22 to 0.64
Mason 2007Malalignment >3°: a meta-analytic mean OR 0.34 (95% CI 0.24 to 0.48)
Malalignment >2°: a meta-analytic mean OR 0.29 (95% CI 0.14 to 0.56)
Brin, 2011Femoral angle (prospective randomized and retrospective studies) OR=0.19 (95% CI 0.08 to 0.39)
Moskal 2014Standardized difference in means: −0.663; 95% CI −0.929 to −0.397, p=0.000
Coronal plane tibial component outliers
Fu, 2012Malalignment of >3°: the OR was estimated at 0.29 (95% CI 0.16 to 0.50)
Rebal 2014Within 3° of ideal (90°) demonstrated equivalent results in the CAS group
(92.1% (83–100%)) and the CONV group (91.7% (82–97%)) (p=0.73; 95% CI −0.06 to 0.09)
Shi 2014 No difference between the two groups.
Mason 2007Malalignment >3°: a meta-analytic mean OR 0.36; 95% CI 0.23 to 0.57
Malalignment >2°: a meta-analytic mean OR 0.26; 95% CI 0.17 to 0.40
Brin, 2011Tibial angle (prospective randomized and retrospective studies): OR=0.19 (0.07 to 0.41)
Moskal 2014Standardized difference in means: −0.268; 95% CI −0.350 to −0.185, p=0.000
Sagittal femoral component malalignment
Fu, 2012Malalignment of >3°: OR=0.35; 95% CI 0.17 to 0.74
Malalignment at >2°: OR=0.22; 95% CI 0.06 to 0.76
Mason, 2007Malalignment >3°: a meta-analytic mean OR=0.39; 95% CI 0.11 to 1.34
Malalignment >2°: a meta-analytic mean OR=0.13; 95% CI 0.03 to 0.54
Femoral slope
FMoskal, 2014Femoral slope outliers: OR=0.465; 95% CI 0.303 to 0.712, p=0.000
Tibial slope
Fu, 2012Malalignment of >3°: OR=0.43; 95% CI 0.30 to 0.61
Malalignment at >2°: OR=0.42; 95% CI 0.23 to 0.76
Mason 2007Malalignment >3°: a meta-analytic mean OR=0.43; 95% CI 0.13 to 1.39
Malalignment >2°: a meta-analytic mean OR=0.31; 95% CI 0.16 to 0.61
Moskal 2014Standardized difference in means: −0.268; 95% CI −0.350 to −0.185, p=0.000
Tibial slope outliers: OR=0.474; 95% CI 0.309 to 0.729, p=0.001
Tibiofemoral mismatch
Mejer, 2014Standardized mean difference=−0.37 (−1.67 to −0.08)
Component axial rotation
 Mejer 2014Postoperative rotation of the femoral component: standardized mean difference = −7° (−0.19 to 0.04)
Postoperative rotation of the tibial component=0.110.010.24)
Number of femoral rotational: pooled OR=1.05 (0.78 to 1.43)
Number of tibial rotational: pooled OR=1.12 (0.68 to 1.47)
Patient safety outcomes of SRs that addressed TKA
Allogenic blood transfusion rate
Han 2016The difference is not statistically significant OR 0.70; 95 % CI 0.49 to 1.01; I 2=0%
Operative blood loss
Xie, 2012No significant difference. Mean standard difference=-54.38; 95% CI -119.76 to 11.00; p=0.10)
Moskal 2014No difference
Change in hemoglobin concentration/hematocrit before and after surgery
Han, 2016The pooled mean difference in change of hemoglobin was −0.39 g/ dL (95 % CI −0.67 to −0.11, p=0.006; I2=75 %)
The pooled mean difference of change of hematocrit was similar in the two groups (0.24%; 95 % CI −0.89% to 0.41%; N.S.; I2=25%)
Postoperative blood loss via drainage
Han, 2016The pooled standard mean difference in drainage blood loss was −83.1 mL (95 % CI −159.0 to −7.1, p=0.03; I2=75 %)
Calculated total blood loss
Han, 2016The pooled standard mean difference in calculated total blood loss was −185.4 mL (95 % CI −303.3 to −67.5 mL; p=0.002)
Tourniquet time
Moskal 2014CONV had significantly lower tourniquet times: standardized difference in means: 0.993; 95% CI 0.567 to 1.419, p=0.000
Allogenic blood transfusion rate
Han, 2016The difference is not statistically significant OR 0.70; 95 % CI 0.49 to 1.01; I2=0%
Complications/adverse events
Alcelik, 2016The OR between the MIS CA and the MIS group was 1.31; 95% CI 0.47 to 3.65, p=0.61
Cheng, 2011 (B)No significant difference (RR=1.50; 95% CI 0.44 to 5.11, p=0.51)
Bauwens 2007Risk ratio, 0.69; 95% CI 0.44 to 1.08. There was no evidence of a difference in infection rates (risk ratio, 0.97; 95% CI 0.33 to 2.85) or the onset of thromboembolic events (risk ratio, 0.64; 95% CI 0.31 to 1.34)
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  • CA, computer assisted; CAS, computer-assisted surgery; CONV, conventional; KSS, Knee Society Score; MIS, Minimally invasive; NAV, navigation; ROM, range of motion; RR, relative risk; SR, systematic review; TKA, total knee arthroplasty; WMD, Weighted mean difference; WOMAC, Western Ontario and McMaster Universities Osteoarthritis Index.