Limb length discrepancy after total knee arthroplasty: A systematic review and meta-analysis

Table 5 Correlation of limb length discrepancy to functional outcome

Ref.	Functional score	Functional outcome	LLD vs functional outcome	Perceived LLD	Remarks
Vaidya et al[11], 2010	Knee society clinical rating system	Mean score in UL group was 73 ± 16.79 (95%CI: 66.73-79.27 (range 45-100)	No LLD (5): Functional score 85; LLD 10 mm (5): functional score 83; LLD 20 mm (19): Functional score 68.16; LLD 30 mm (1): Functional score 55; < 10 mm (21): 82.1429 ± 9.439; ≥ 10 mm (39): 73.9744 ± 5.261	26.66% (8) pts perceived LLD; no LLD: Not perceived; LLD 10 mm: Not perceived; LLD 20 mm: 7 patients; LLD 30 mm: One patient	The functional outcome after UL TKA in BL OA knee with varus deformity is inferior to BL TKA
	Knee society clinical rating system	Mean score in BL group was 80.67 ± 21.2 (95%CI: 72.75 -88.58, range 0-100).	No LLD (16): Functional score 81.25; LLD 10 mm (13): Functional score 80; LLD 20 mm (1): Functional score 80	No one perceived LLD
Kim et al[4], 2015	KSS function score		LLD > 15 mm: KSS function score 88.2 ± 7.0; LLD ≤ 15 mm: KSS function score 80.1 ± 14.7 (S); no difference in ROM, HSS, KSS knee score and WOMAC	Not evaluated	Patients with LLD of > 15 mm had significantly inferior outcome than LLD < 15 mm. Preop LLD has high risk of postop LLD. Patients with unilateral TKA have higher chances of postoperative LLD
Chinnappa et al[16], 2017	WOMAC; KSS knee; KSS; function 6 mo		LLD < 10 mm: 89% pts.; LLD ≥ 10 mm: 11% pts. a: 37.1 ± 16 in ≥ 10 mm LLD vs 30.8 ± 21.2 with < 10 mm LLD (NS); b: 37 ± 20.8 in ≥ 10 mm LLD vs 29.2 ± 35.2 with < 10 mm LLD (NS); c: 29.4 ± 21.2 in ≥ 10 mm LLD vs 23.6 ± 27.7 with < 10 mm LLD (NS)	Preoperative LLD: 16% pts. Postoperative LLD: 21% pts. a: 13.1 ± 22.6 in ≥ 10 mm LLD vs 35.5 ± 18.8 with < 10 mm LLD (S); b: 16.2 ± 26.2 in ≥ 10 mm LLD vs 31.0 ± 34.1 with < 10 mm LLD (NS); c: 15.3 ± 28.9 vs 26.1 ±27.1 (NS)	Significant radiological LLD (≥ 10 mm) after TKA is uncommon (11%) and doesn’t correlate to perceived LLD. Perceived LLD is associated with decreased satisfaction and function
Hinarejos et al[17], 2020	Function KSS	Mean preop score of 51.3 ± 13.5 improved to 80.5 ± 15.1 at 12 mo (P < 0.0001)	LLD < 10 mm (422, 91.7%): Functional score 82.3 (14.6). LLD ≥ 10 mm (38, 8.3%): Functional score 76.7 (14.0)	Not evaluated	Patients with LLD of > 10 mm had significantly worse outcome

S: Significant P < 0.05; NS: Non-significant P > 0.05; KSS: Knee society score; HSS: Hospital for special surgery score; WOMAC: Western Ontario and McMaster Universities scores; LLD: Limb length discrepancy; TKA: Total knee arthroplasty.