Alignment of the hindfoot following total knee arthroplasty: A systematic review

Table 1 Inclusion and exclusion criteria

Inclusion criteria	Exclusion criteria
Clinical studies related to changes in the hindfoot following TKA	Less than 10 patients
Published in a peer review journal	Case reports
Written in English	Cadaveric studies
Full text version available	Animal studies
	Review articles
	In vivo studies

TKA: Total knee arthroplasty.

Table 2 Study characteristics and patient demographics

Ref.	LOE	Patients, n (%)	Knees, n (%)	Age (yr)	Sex (M/F)	Follow-up (mo)	MCMS
Chandler and Moskal[6], 2004	2	86	86	N/R	N/R	3	48
Cho et al[7], 2017	2	117	195	69.1	8/187	24	66
Hara et al[8], 2015	3	100	100	74.3	14/86	0.75	48
Jeong et al[9], 2018	2	331	375	68.3	23/308	6	60
Kim et al[10], 2018	3	55	65	69.3	N/R	31.3	71
Levinger et al[11], 2012	2	19	26	67.5	13/6	12	46
Mansur et al[12], 2019	2	72	72	N/R	23/49	3	44
Mullaji and Shetty[13], 2011	2	125	165	66.1	24/101	12	51
Okamoto et al[14], 2017	3	75	80	72.5	8/67	24	48
Palanisami et al[15], 2020	3	91	121	63.4	29/62	12	58
Takenaka et al[16], 2016	3	71	73	74.7	17/56	12	48

LOE: Level of evidence; M/F: Male/female; MCMS: Modified Coleman methodological score.

Table 3 Summary of outcomes

				Radiographic Assessment			AOFAS
Ref.	Patients, n (%)	Knees, n (%)	Knee deformity	Hindfoot	Ankle	Lower limb alignment	Pre-op	Post-op	Postoperative outcomes
Chandler and Moskal[6], 2004	86	86	Both valgus and varus	TCA: Pre-op = 0.4°; Post-op = -0.1°		FTA: Pre-op = 3.6°; Post-op = 6.6°			Both valgus and varus hindfoot alignment improved post TKA
									Valgus hindfoot alignment remained in valgus alignment post TKA
									Varus hindfoot alignment remained in varus alignment post TKA
Cho et al[7], 2017	117	195	Varus only	TCA: Pre-op = 5.2° valgus; Post-op = 2.1° valgus		Mechanical alignment angle: Pre-op = 10.8° varus; Post-op = 1.8° varus			Valgus hindfoot alignment improved post TKA
									Severe varus knee deformities had best improvement in hindfoot alignment post TKA
Hara et al[8], 2015	100	100	Varus only	VVA: Pre-op = 78.8°; Post-op = 76.7°		FTA: Pre-op = 186.7°; Post-op = 174.4°			Varus hindfoot alignment with varus knee deformity remained in varus alignment post TKA
									Valgus hindfoot alignment with varus knee deformity improved post TKA
Jeong et al[9], 2018	331	375	Varus only	HA: Pre-op = 13.5°; Post-op = 5.8°. HR: Pre-op = 0.2°; Post-op = 0.3°. HD: Pre-op = 11.0°; Post-op = 5.2°	TT: Pre-op = 0.4°; Post-op = 0.1°. GD: Pre-op = 6.5°; Post-op = 0.2°. TAS: Pre-op = 92.0°; Post-op = 92.0°. TLS: Pre-op = 81.8°; Post-op = 81.3°	Mechanical axis: Pre-op = 11.1° varus; Post-op = 0.3° varus			Valgus hindfoot alignment improved post TKA
									Subtalar joint became more varus post TKA
Kim et al[10], 2018	55	65	Varus only	HAVA: Pre-op = 6.1°; Post-op = 5.7°	TT: Pre-op = 1.9°; Post-op = 1.7°. TAS: Pre-op = 85.9°; Post-op = 84.9°. MCS: Pre-op = 2.4 mm; Post-op = 2.6 mm. MTTJS: Pre-op = 2.8°; Post-op = 2.3°. FTGA: Pre-op = 85.6°; Post-op = 86.5°	Mechanical axis deviation angle: Pre-op = 10.0°; Post-op = 1.9°	95.2	91.5	Valgus hindfoot alignment slightly improved post TKA
									Newly developed ankle pain post TKA was associated with larger degrees of residual varus knee deformity
Levinger et al[11], 2012	19	26	Varus only	FPI: Pre-op = 2.9°; Post-op = 2.7°		FTA: Pre-op = -1.2°; Post-op = 4.9°			Increased range of motion of the rearfoot in the frontal plane post TKA
									No change in static foot pressure post TKA
Mansur et al[12], 2019	72	72	Both varus and valgus	Intersection of the load axis of the leg and the calcaneus axis: Pre-op = -3.8°; Post-op = -4.4°		FTA: Pre-op = ?	74.3	89.4	Varus hindfoot alignment with varus knee deformity remained in varus alignment post TKA
									Varus hindfoot alignment with valgus knee deformity, valgus hindfoot alignment with valgus knee deformity and valgus hindfoot alignment with varus knee deformity all improved post TKA
Mullaji and Shetty[13], 2011	125	165	Both varus and valgus	TCA: Pre-op = 188°; Post-op = 185.5°		CMAD: Pre-op = 34.3 mm; Post-op = 0.0 mm. GMAD: Pre-op = 31.0 mm; Post-op = -6.0 mm			Valgus hindfoot alignment with varus knee deformity improved post TKA
									87% of patients had persistent valgus hindfoot alignment post TKA
Okamoto et al[14], 2017	75	80	Varus only	Calcaneal pitch: Pre-op = 14.9°. Naviculocuboid overlap: Pre-op = 84.7°; Post-op = 65.7°	TT: Pre-op = 13.1°; Post-op = 4.4°. TI: Pre-op = 9.9°; Post-op = 0.8°	Mechanical axis: Pre-op = 5.0°; Post-op = 0.7°	46.6	60.2	Valgus hindfoot alignment with severe varus knee deformity did not improve post TKA
									Valgus hindfoot alignment with moderate varus knee deformity improved post TKA
Palanisami et al[15], 2020	91	121	Varus only	TH: Pre-op = 9.9°; Post-op = 4.7°. VVI: Pre-op = -0.29; Post-op = -0.04		FTMA: Pre-op = 162.0°; Post-op = 178.8°	59.2	88.7	Valgus hindfoot alignment with varus knee deformity improved post TKA
									TKA restores foot loading pattern medially
Takenaka et al[16], 2016	71	73	Varus only	VVA: Preop = 78.2; Post-op = 76.0		FTA: Pre-op = 184.8; Post-op = 173.9			Valgus hindfoot alignment with varus knee deformity improved post TKA
									Varus hindfoot alignment with varus knee deformity did not improve post TKA

TKA: Total knee arthroplasty; FTA: Femoral-tibial angle; VVA: Varus valgus angle; TH: Tibial hindfoot; VVI: Varus-valgus index; FTMA: Femorotibial mechanical angle; AOFAS: American Orthopaedic Foot and Ankle Society; TCA: Tibio-calcaneal angle; FPI: Foot posture index; MTTJS: Medial tibiotalar joint space; FTGA: Frontal tibial ground angle; HA: Hindfoot alignment; CMAD: Conventional mechanical axis deviation.

Table 4 Hindfoot radiographic parameters

Hindfoot radiographic parameters	Studies, n (%)
TCA	3 (27.3)
VVA	2 (18.2)
HAVA	1 (9.1)
Intersection of the load axis of the leg and the calcaneus axis	1 (9.1)
TH	1 (9.1)
Calcaneal pitch	1 (9.1)
Naviculocuboid overlap	1 (9.1)
FPI	1 (9.1)
HA	1 (9.1)
HR	1 (9.1)
HD	1 (9.1)

TCA: Tibiocalcaneal angle; VVA: Varus valgus angle; HAVA: Hindfoot alignment view angle; TH: Tibial hindfoot angle; FPI: Foot posture index; HA: Hindfoot alignment angle; HR: Hindfoot alignment ratio; HD: Hindfoot alignment diameter.