Correlation of stress radiographs to injuries associated with lateral ankle instability

Table 1 Anterior drawer (mean ± SD)

Outcome	Outcome = No			Outcome = Yes			P value
	n	mean	SD	n	mean	SD
Peroneal tendonitis	65	4.5	2.7	22	4.9	3.2	0.533
Peroneal tear	81	4.7	2.7	6	3.4	4.0	0.251
MRI OLT	45	5.0	3.0	42	4.2	2.5	0.206
MRI OLT < 1 cm	61	4.9	2.9	26	3.9	2.4	0.107
MRI > 1 cm	71	4.6	2.9	16	4.8	2.6	0.791
Broström	23	4.7	2.2	64	4.6	3.0	0.805
Operative peroneal exploration	68	4.7	2.8	19	4.4	2.8	0.675
Operative peroneal repair	85	4.6	2.8	2	5.8	1.7	0.548
Operative OLT microfracture/chondroplasty	52	5.1	2.8	35	3.9	2.7	0.066
Operative OLT restoration/repair	80	4.6	2.9	7	4.9	1.8	0.753

MRI: Magnetic resonance imaging; OLT: Osteochondral lesions of the talus.

Table 2 Tilt angle (mean ± SD)

Outcome	Outcome = No			Outcome = Yes			P value
	n	mean	SD	n	mean	SD
Peroneal tendonitis	65	7.5	5.4	22	11.8	6.7	0.004
Peroneal tear	81	8.2	6.0	6	13.8	4.4	0.026
MRI OLT	45	9.8	6.0	42	7.3	5.8	0.051
MRI OLT < 1 cm	61	8.8	6.3	26	8.1	5.4	0.610
MRI > 1 cm	71	9.2	5.8	16	6.0	6.4	0.057
Broström	23	3.3	3.3	64	10.5	5.6	< 0.001
Operative peroneal exploration	68	8.3	6.0	19	9.7	6.0	0.372
Operative peroneal repair	85	8.6	6.0	2	10.0	8.5	0.739
Operative OLT microfracture/chondroplasty	52	9.1	6.2	35	7.8	5.8	0.339
Operative OLT restoration/repair	80	9.0	6.0	7	4.4	4.9	0.057

MRI: Magnetic resonance imaging; OLT: Osteochondral lesions of the talus.

Table 3 Anterior drawer median and inter quartile range

Outcome	Outcome = No			Outcome = Yes			P value
	n	Median	IQR	n	Median	IQR
Peroneal tendonitis	65	4.5	3.0-6.6	22	4.8	4.0-7.0	0.487
Peroneal tear	81	4.6	3.3-7.0	6	2.1	0.0-7.0	0.318
MRI OLT	45	5.2	2.7-7.5	42	4.3	3.0-5.6	0.110
MRI OLT < 1 cm	61	5.1	3.3-7.1	26	4.2	3.0-5.0	0.062
MRI > 1 cm	71	4.6	2.7-7.0	16	4.7	3.7-6.9	0.891
Broström	23	4.7	4.0-6.9	64	4.5	2.4-7.1	0.870
Operative peroneal exploration	68	4.9	3.3-6.9	19	4.3	2.7-7.0	0.550
Operative peroneal repair	85	4.5	3.0-7.0	2	5.8	4.6-7.0	0.514
Operative OLT microfracture/chondroplasty	52	5.1	3.7-7.2	35	4.1	2.7-5.6	0.035
Operative OLT restoration/repair	80	4.5	2.9-7.0	7	4.8	4.0-6.9	0.827

MRI: Magnetic resonance imaging; OLT: Osteochondral lesions of the talus; IQR: Inter quartile range.

Table 4 Tilt angle median and inter quartile range

Outcome	Outcome = No			Outcome = Yes			P value
	n	Median	IQR	n	Median	IQR
Peroneal tendonitis	65	7	3-12	22	12	6-18	0.0081
Peroneal tear	81	8	3-12	6	15	10-16	0.0201
MRI OLT	45	9	5-14	42	6	2-13	0.0431
MRI OLT < 1 cm	61	8	3-14	26	8	3-13	0.763
MRI > 1 cm	71	8	4-13	16	3	1-10.5	0.0251
Broström	23	3	1-4	64	10	6.5-14	< 0.0011
Operative peroneal exploration	68	8	3-12	19	11	4-15	0.318
Operative peroneal repair	85	8	3-13	2	10	4-16	0.670
Operative OLT microfracture/chondroplasty	52	8	4-13	35	7	3-13	0.360
Operative OLT restoration/repair	80	8	3.5-13	7	3	1-6	0.0391

¹Significant difference. MRI: Magnetic resonance imaging; OLT: Osteochondral lesions of the talus; IQR: Inter quartile range.

Table 5 Initial analysis of the talar tilt

	Talar tilt ≥ 10°	Talar tilt < 10°	Sn (%)	Sp (%)	PPV (%)	NPV (%)
Peroneal tendonitis	13/35	9/52	59	66	37	83
Peroneal tear	5/35	1/52	83	63	14	98
Any peroneal pathology	14/35	10/52	58	67	40	81
Any OLT	15/35	27/52	36	56	43	48

The sensitivity, specificity, positive predictive value, and negative predictive value are documented for the presence or absence of peroneal pathology in relationship to the talar tilt stress radiograph. Note that given the significant inverse relationship found between osteochondral lesions of the talus and stress radiographs, the predictive statistics were inverted as well utilizing a positive test as being a talar tilt < 10°. Sn: Sensitivity; Sp: Specificity; PPV: Positive predictive value; NPV: Negative predictive value; OLT: Osteochondral lesions of the talus.

Table 6 The anterior drawer test

	Anterior drawer < 5 mm	Anterior drawer ≥ 5 mm	Sn (%)	Sp (%)	PPV (%)	NPV (%)
OLT	30	13	70	57	64	68

The sensitivity, specificity, positive predictive value, and negative predictive value are documented for the presence or absence of peroneal pathology in relationship to the anterior drawer stress radiograph. Note that given the significant inverse relationship found between osteochondral lesions of the talus and stress radiographs, the predictive statistics were inverted as well utilizing a positive test as being an anterior drawer < 5 mm. Sn: Sensitivity; Sp: Specificity; PPV: Positive predictive value; NPV: Negative predictive value; OLT: Osteochondral lesions of the talus.