Coronal plane alignment of the knee phenotypes and ankle joint coronal plane alignment patterns in Egyptian population

Table 1 Demographic characteristics and angle measurements of the included participants

Parameter	n (%)	mean ± SD	95% confidence interval
527 participants (1054 knees)
Age		57.21 ± 7.78	56.55-57.87
Sex
Female	419 (79.5)
Male	108 (20.5)
MPTA (°)		85.46 ± 3.5	85.25-85.67
mLDFA (°)		90.97 ± 3.12	90.78-91.16
aHKA (°)		-5.51 ± 4.84	-5.80 to -5.22
JLO (°)		176.43 ± 4.53	176.16-176.70
435 participants (870 knees and ankles)
Age		56.6 ± 8.5	55.80-57.40
Sex
Female	343 (78.9)
Male	92 (21.1)
aHKA (°)		-5.30° ± 4.84°	5.60 to -5.00
JLO (°)		176.34° ± 4.71°	176.04-176.64
TPHA (°)		-5.21 ± 6.45	-5.64 to -4.78

MPTA: Medial proximal tibial angle; mLDFA: Mechanical lateral distal femoral angle; aHKA: Arithmetic hip, knee, and ankle; JLO: Joint line obliquity; TPHA: Tibial plateau horizontal angle.

Table 2 Coronal plane alignment of the knee classification of the included participants, n = 527 participants, 1054 knees, n (%)

Variables		aHKA (MPTA-mLDFA)			Total
		Varus (< -2)	Neutral (-2 to +2)	Valgus (> +2)
JLO (MPTA + mLDFA)	Apex distal (< 177)	Type I1: 467 (44.3)	Type II1: 105 (10)	Type III: 11 (1)	583 (55.31)
	Neutral (177:183)	Type IV1: 301 (28.6)	Type V: 88 (8.3)	Type VI: 20 (1.9)	409 (38.80)
	Apex proximal (> 183)	Type VII: 37 (3.5)	Type VIII: 11 (1)	Type IX: 14 (1.3)	62 (5.88)
Total		805 (76.38)	204 (19.35)	45 (4.27)	1054 (100) knees

¹Indicated the three commonly occurring types.

JLO: Joint line obliquity; MPTA: Medial proximal tibial angle; mLDFA: Mechanical lateral distal femoral angle; aHKA: Arithmetic hip, knee, and ankle.

Table 3 Coronal plane alignment of the knee and ankle joint line orientation combined subtypes, n = 435 participants, 870 knees and ankles, n (%)

Variables		AJLO types			Total knees
		Varus: TPHA < 0 (type A)	Neutral: TPHA =0 (type N)	Valgus: TPHA > 0 (type B)
CPAK types	I	Type I-A1: 293 (33.7)	Type I-N1: 60 (6.9)	Type I-B: 32 (3.7)	385 (44.25)
	II	Type II-A: 56 (6.4)	Type II-N: 23 (2.6)	Type II-B: 11 (1.3)	90 (10.34)
	III	Type III-A: 3 (0.3)	Type III-N: 6 (0.7)	Type III-B: 2 (0.2)	11 (1.26)
	IV	Type IV-A1: 187 (21.5)	Type IV-N: 43 (4.9)	Type IV-B: 11 (1.3)	241 (27.70)
	V	Type V-A: 35 (4)	Type V-N: 27 (3.1)	Type V-B: 11 (1.3)	73 (8.39)
	VI	Type VI-A: 8 (0.9)	Type VI-N: 5 (0.6)	Type VI-B: 6 (0.7)	19 (2.18)
	VII	Type VII-A: 20 (2.3)	Type VII-N: 3 (0.3)	Type VII-B: 2 (0.2)	25 (2.87)
	VIII	Type VIII-A: 5 (0.6)	Type VIII-N: 6 (0.7)	Type VIII-B: 0 (0.0)	11 (1.26)
	IX	Type IX-A: 4 (0.5)	Type IX-N: 7 (0.8)	Type IX-B: 4 (0.5)	15 (1.72)
Total ankles		611 (70.23)	180 (20.69)	79 (9.08)	870 (100)

¹Indicated the three commonly occurring types.

CPAK: Coronal plane alignment of the knee; AJLO: Ankle joint line orientation; TPHA: Tibial plateau horizontal angle.

Table 4 Comparison between the current study results and studies published from other populations, n (%)

Ref.	Study population	Sample size		Age (years)	Sex		Radiographic parameters (degrees)				CPAK types
		Patients	Knees		Male	Female	mLDFA	MPTA	aHKA	JLO	I	II	III	IV	V	VI	VII	VIII	IX
Macdessi et al[5], 2021	Australia	500	500	66	190 (38)	310 (62)	88.1 ± 2.1	87.3 ± 2.1	-0.8 ± 2.8		97 (19.4)	161 (32.2)1	77 (15.4)	49 (9.8)	73 (14.6)	37 (7.4)	3 (0.6)	8 (1.6)	2 (0.4)
Sappey-Marinier et al[45], 2022	France	936	1078	71.3 ± 8	780 (83)	156 (17)	88.5 ± 2.6	86.8 ± 3.1	-1.7 ± 3.5	176.0 ± 4.5	360 (33.4)1	210 (19.5)	115 (10.6)	110 (10.2)	204 (18.9)	68 (6.3)	4 (0.4)	6 (0.6)	1 (0.1)
Mulpur et al[34], 2022	India	250	500	62.3 ± 8.2	76 (30.4)	174 (69.6)	90.2 ± 3.6	83.4 ± 3.4	-6.9 ± 5	173.5 ± 5.0	294 (58.8)1	69 (13.8)	7 (1.4)	91 (18.2)	17 (3.4)	5 (1.0)	14 (2.8)	3 (0.6)	0 (0.0)
Toyooka et al[41], 2023	Japan	343	500	75.1 ± 8	95 (19)	405 (81)	88 ± 2.9	84.4 ± 3.3	-3.5 ± 4.8	172.4 ± 3.8	269 (53.8)1	127 (25.4)	41 (8.2)	36 (7.2)	22 (4.4)	5 (1.0)	0	0	0
Huber et al[46], 2023	Austria	7456	8739	69 ± 9.3	2502	4954	87.3 ± 2.8	87.2 ± 3.2	-0.1 ± 4.8	174.5 ± 3.6	2454 (28.1)1	2383 (27.3)	1830 (20.9)	539 (6.2)	658 (7.55)	754 (8.6)	30 (0.3)	29 (0.3)	62 (0.7)
Coetzee et al[36], 2024	South Africa	344	608	68.4 ± 9.2	76 (22.1)	268 (77.9)	87.2 ± 3	88.2 ± 2.8	1 ± 4.8	175.2 ± 3.4	94 (15.5)	155 (25.5)	174 (28.6)1	45 (7.4)	52 (8.6)	80 (13.2)	3 (0.5)	1 (0.2)	4 (0.7)
Araki et al[42], 2024	Japan	95	143		21	74	88.7 ± 3.1	83.9 ± 3.4	NR	NR	94 (66)1	21 (15)	14 (10)	9 (6)	3 (2)	1 (0)	1 (0)	0 (0)	0 (0)
Wong et al[43], 2024	Malysia	500	500	66.4 ± 6.7	160 (32)	340 (68)	87.6 ± 2.4	85.8 ± 3	-1.8 ± 4.2	173.4 ± 3.45	(43.4)	(27.6)	(14.2)	(4)	(8.6)	(2.2)	(0)	(0)	(0)
Gao et al[47], 2024	China	246	477	65.3 ± 7.3	65	181	88.6 ± 3.6	85 ± 3.8	-3.6 ± 5.8	173.6 ± 4.6	(43.6)	(21.6)	(10.5)	(11.5)	(7.5)	(3.8)	(1.1)	(0)	(0.4)
Şenel et al[40], 2024	Turkey	296	408	54.5 ± 7.9	141 (47.6)	155 (52.4)	88 ± 2.9	86.6 ± 2.6	-1.4 ± 3.9	174.6 ± 3.7	115 (28.2)	129 (31.6)1	55 (13.5)	42 (10.3)	50 (12.3)	10 (2.5)	4 (1)	0 (0)	3 (0.7)
León-Muñoz et al[37], 2024	Spain	447	501	69.9 ± 6.3	288 (64.4)	159 (35.6)	89.8 ± 2.8	86.4 ± 2.8	-3.4 ± 4.3	176.2 ± 3.6	(30.7)1	(21)	(5)	(25.9)	(11.2)	(2.8)	(2.4)	(0.6)	(0.4)
Dragosloveanu et al[39], 2024	Romania	500	500	68 ± 7.2	125 (25.4)	375 (74.6)	88.8 ± 3.2	86.2 ± 3.4	-2.6 ± 5.2	175 ± 4.1	212 (42.4)1	84 (16.8)	49 (9.8)	81 (16.2)	37 (7.4)	23 (4.6)	6 (1.2)	5 (1)	3 (0.6)
Samant and Desai[36], 2024	India	NR	250	59 ± 8	41	59	90.2 ± 4.5	85.7 ± 5	-4.5 ± 7.5	175.9 ± 5.9	84 (33.6)	34 (34)1	15 (6)	56 (22.4)	5 (29)	6 (15)	7 (8)	8 (4)	9 (5)
Park et al[44], 2025	United Arab Emirates	1098	2196	48.7 ± 14.1	51.5	48.5	87.9 ± 2.8	86.4 ± 2.9	-1.5 ± 4.1	174.3 ± 3.9	775 (35.3)1	657 (29.9)	302 (13.8)	161 (7.3)	183 (8.3)	87 (4.0)	21 (1.0)	5 (0.2)	5 (0.2)
	South Korea	7138	14,276	59.9 ± 15.8	24.8	75.20	87.6 ± 2.7	86.9 ± 2.7	-0.8 ± 3.7	174.5 ± 3.8	3662 (25.7)	4801 (33.6)1	2303 (16.1)	1204 (8.4)	1393 (9.8)	686 (4.8)	89 (0.6)	87 (0.6)	50 (0.4)
Pujol et al[38], 2025	Spain	121	NR	71.7 ± 7.5	48 (40)	73 (60)	87.4 ± 2.7	87.1 ± 2.6	-0.4 ± 4.2	174.5 ± 3.3	(23.1)	(28.1)1	(23.1)	(8.30)	(11.60)	(5.80)	(0)	(0)	(0)
Current study	Egypt	527	1054	57.21 ± 7.78	108 (20.5)	419 (79.5)	90.9 ± 3.1	85.5 ± 3.5	-5.5 ± 4.8	176.4 ± 4.5	467 (44.3)1	105 (10)	11 (1)	301 (28.6)	88 (8.3)	20 (1.9)	37 (3.5)	11 (1)	14 (1.3)

¹Indicated the most commonly occurring coronal plane alignment of the knee type in each study.

CPAK: Coronal plane alignment of the knee; mLDFA: Mechanical lateral distal femoral angle; MPTA: Medial proximal tibial angle; aHKA: Arithmetic hip, knee, and ankle; JLO: Joint line obliquity; NR: Not reported.