Table 2 Pooled kneeling results from comparative studies

High-flexion versus conventional TKA design

No difference between groups (46% in high flexion TKA versus 44% in conventional TKA, OR 1.1, 95% CI 0.5–2.4, p = 0.84) Seon et al. [12]

Patellar resurfacing versus non-resurfacing

No difference between groups (42.7% without resurfacing versus 35.0% with resurfacing; OR 1.6, 95% CI 0.6–4.4, p = 0.35) Huish et al. [13]; Garneti et al. [14]

Anterolateral versus midline/medial skin incision

No difference between groups (80.8% with anterolateral incision versus 58.3% with anteromedial incision; OR 3.0, 95% CI 1.3–6.9, p = 0.02) Tsukada et al. [15]

Mini-length (mean 10.5 cm) versus standard length (mean 18.5 cm) midline skin incision

Significant difference between groups (40% with MIS versus 0% with standard surgery at 6 months; OR 34.6, 95% CI 1.9–631.9, p = 0.02 and 80% with MIS versus 32% with standard surgery at 2 years; OR 8.5 95% CI 2.3–30.9, p = 0.001) Kashyap et al. [16]

Transverse versus longitudinal skin incision

Significant difference between groups (70.4% with transverse incision versus 40.6% with longitudinal incision; OR 3.5, 95% CI 1.4–8.7, p = 0.008) Ojima et al. [17]

Mobile versus fixed platform design

No difference between groups at 1-year follow-up (25.6% with mobile prosthesis versus 36.4% with fixed design; OR 0.6, 95% CI 0.3–1.2, p = 0.14) Kim et al. [18]; Artz et al. [19]

Mobile platform inferior to fixed platform at 2-year follow-up (10.8% able to kneel with little or no difficulty with mobile prosthesis versus 27.5% with fixed design; OR 0.3, 95% CI 0.1–0.7, p = 0.005) Artz et al. [19]

Two different mobile-bearing prosthesis designs

No difference between groups (37.5% with rotation platform versus 21.1% with mobile design; OR 2.3, 95% CI 0.5–10.1, p = 0.29) Nam et al. [20]

High-flexion versus mobile platform design

No difference between groups (40% in high-flexion group versus 36% with fixed design; OR 1.2, 95% CI 0.5–2.7, p = 0.68) Seon et al. [21]

Cruciate-retaining versus posterior-stabilized design

No difference between groups (40.0% for cruciate retaining versus 37.5% for posterior substituting design; OR 1.1, 95% CI 0.4–3.1, p = 0.84) Zhang et al. [22]