Occult syndesmotic injury in chronic lateral ankle instability treated with Broström repair and suture-button stabilization

Table 1 Individual characteristics, treatment details, and outcomes of the 16 patients

Patient No.	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
Age (years)	55	52	21	50	29	36	31	19	33	25	48	51	67	53	56	54
Side	R	L	R	R	L	R	L	L	R	R	L	R	R	L	L	R
Sex	F	F	M	F	F	F	M	F	F	F	M	F	F	F	F	F
Body mass index (kg/m2)	23.63	23.88	23.29	23.05	22.04	21.72	26.17	17.65	22.86	29.38	26.20	24.84	18.99	19.15	21.93	24.8
Injury mechanism	Walking downstairs	Walking on level ground	Sports	Sports	Walking downstairs	Sports	Sports	Sports	Walking downstairs	Sports	Walking downstairs	Sports	Sports	Fall from a height	Fall from a height	Fall from a height
Injury-to-surgery interval (months)	120	120	9	360	4	120	18	60	24	120	5	4	12	24	12	6
VAS, preoperative	3	3	3	1	6	4	4	2	2	2	3	4	2	4	1	4
VAS, 1 year postoperative	0	2	0	0	0	0	1	0	0	0	3	2	2	0	0	0
VAS, 3 years postoperative	0	2	0	0	1	0	0	0	0	0	2	2	1	0	0	1
VAS, 5 years postoperative	0	1	0	0	1	0	0	0	0	0	2	1	1	0	0	1
AOFAS, preoperative	75	58	80	83	44	64	60	77	79	84	70	69	61	54	87	70
AOFAS, 1 year postoperative	96	81	100	92	96	89	92	100	98	100	79	76	80	91	99	80
AOFAS, 3 years postoperative	96	84	100	92	92	90	92	100	98	100	80	78	82	91	99	84
AOFAS, 5 years postoperative	96	86	100	94	94	91	93	100	98	100	82	80	83	92	99	85
FAAM, preoperative	72.62	55.95	89.29	76.19	50.00	76.19	60.00	77.38	78.57	82.14	60.71	59.52	60.71	54.76	85.71	75.00
FAAM, 1 year postoperative	96.43	82.14	100.00	86.90	97.62	88.10	80.95	94.04	90.48	100.00	63.10	69.05	73.81	88.10	100.00	91.67
FAAM, 3 years postoperative	96.43	86.90	100.00	86.90	95.24	88.10	80.95	94.04	90.48	100.00	65.48	69.05	73.81	88.10	100.00	95.24
FAAM, 5 years postoperative	96.43	88.10	100.00	88.10	95.24	90.48	83.33	95.24	92.86	100.00	66.67	71.43	76.19	88.10	100.00	95.24
Karlsson, preoperative	62	52	80	75	39	64	55	72	74	79	60	59	57	52	80	64
Karlsson, 1 year postoperative	94	80	100	89	92	85	82	92	90	100	70	69	72	84	97	82
Karlsson, 3 years postoperative	94	82	100	90	89	87	82	95	92	100	72	70	75	85	97	84
Karlsson, 5 years postoperative	95	84	100	90	92	87	84	94	94	100	74	72	77	85	97	85
Residual focal syndesmotic pain	No	No	No	No	No	No	No	No	No	No	No	No	No	No	No	No
Button removal	No	Yes	No	Yes	No	Yes	No	Yes	Yes	No	Yes	No	No	Yes	No	No
Postoperative difficulty with squatting (yes/no)	No	No	No	No	No	Yes	No	Yes	No	No	No	No	No	Yes	No	No
Lateral ligament repair	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Lateral ligament repair approach	Arthroscopic	Arthroscopic	Arthroscopic	Arthroscopic	Arthroscopic	Arthroscopic	Arthroscopic	Open	Open	Open	Open	Open	Arthroscopic	Arthroscopic	Arthroscopic	Open
Return to preinjury work (months)	2.0	2.5	1.0	2.0	2.5	3.0	2.5	2.5	2.0	1.5	3.5	3.5	3.0	3.0	2.0	2.5
Satisfied with surgery	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes

Data are shown for each patient. Age is reported in years; body mass index in kg/m²; injury-to-surgery interval and return to preinjury work in months. AOFAS: American Orthopaedic Foot and Ankle Society; FAAM: Foot and Ankle Ability Measure; VAS: Visual Analogue Scale; R: Right; L: Left.

Table 2 Preoperative and postoperative Visual Analogue Scale, American Orthopaedic Foot and Ankle Society, Foot and Ankle Ability Measure, and Karlsson scores, Friedman statistics, exact P values, and paired effect sizes, mean ± SD

Score	VAS	AOFAS	FAAM	Karlsson
Preoperative	3.00 ± 1.32	69.69 ± 12.11	69.67 ± 12.15	64.00 ± 11.86
Friedman χ2 (df = 3); P	37.59; < 0.001	40.49; < 0.001	40.83; < 0.001	41.35; < 0.001
1 year postoperative	0.62 ± 1.02	90.56 ± 8.64	87.65 ± 11.30	86.12 ± 9.96
Raw P; adjusted P; Cohen’s dz	0.000122; 0.000366; -1.46	0.000031; 0.000092; 1.77	0.000031; 0.000092; 1.66	0.000031; 0.000092; 2.07
3 years postoperative	0.56 ± 0.81	91.12 ± 7.54	88.17 ± 10.86	87.12 ± 9.34
Raw P; adjusted P; Cohen’s dz	0.000031; 0.000092; -1.85	0.000031; 0.000092; 2.00	0.000031; 0.000092; 1.76	0.000031; 0.000092; 2.38
5 years postoperative	0.44 ± 0.63	92.06 ± 6.89	89.21 ± 10.19	88.12 ± 8.69
Raw P; adjusted P; Cohen’s dz	0.000031; 0.000092; -2.03	0.000031; 0.000092; 2.06	0.000031; 0.000092; 1.94	0.000031; 0.000092; 2.40

n = 16 at every time point. Friedman χ² statistics have 3 degrees of freedom. Raw two-sided exact Wilcoxon signed-rank P values and Bonferroni-adjusted P values are reported for each postoperative-versus-preoperative comparison (three planned comparisons per outcome). Cohen’s dz is the mean within-patient change divided by the standard deviation of within-patient changes; negative Visual Analogue Scale values indicate pain reduction. Injury-to-surgery interval was 21.0 months (interquartile range, 8.25-120.0 months). AOFAS: American Orthopaedic Foot and Ankle Society; FAAM: Foot and Ankle Ability Measure; VAS: Visual Analogue Scale.

Table 3 Adverse events and additional procedures, n (%)

Event	Patients	Details
Wound-healing complication	0/16 (0)	None
Surgical-site infection	0/16 (0)	None
Neurologic complication	0/16 (0)	None
Deep venous thrombosis	0/16 (0)	None
Recurrent clinical ankle instability	0/16 (0)	None
Suture-button removal	7/16 (43.8)	Three for persistent symptoms; four at patient request
Other reoperation	0/16 (0)	None
Implant-related symptoms at 5 years	0/16 (0)	None

No adverse event or additional procedure other than suture-button removal occurred during follow-up.