Arthroereisis in juvenile flexible flatfoot: Which device should we implant? A systematic review of literature published in the last 5 years

Table 1 Study results

Ref.	Patients (mean age)	AR type	Assessment	Results	Complications	Limits
Ruiz-Picazo et al[8], 2019	16 (32 FFF), 9 yr (range: 7-11 yr).	Subtalar device. Titanium self-locking device.	OxAFQ-C pre- and postoperatively.	Postoperative results were positive, with statistical significance for the “school and play”, “emotional”, and “footwear” domains of the OxAFQ-C scale (P < 0.05) and no differences in the “physical” domain.	4 (25%). 2 extrusion of the implant and 2 overcorrections.	Retrospective nature, no control group, sample size. lack of objectively measurable parameters.
Pavone et al[16], 2019	105 (174 FFF) (12.6 ± 1.3 yr), mean follow-up 67.5 ± 16.4 mo.	Calcaneo-stop.	BMI-for-age AOFAS, FADI, FADI Sport, and SF-36 at 1 and 3 yr. Variation of the angles measured on X-ray images.	AOFAS, FADI, FADI Sport, and SF-36 scores and radiological assessments improved significantly postoperatively (P = 0.001) and remained stable over time (1 yr: P < 0.001; 5 yr: P < 0.001) in all groups of patients. An increased persistence of pain and/or discomfort in obese patients than in normal weight patients (P = 0.02).	20 (11.5%) patients. 1 screw loosening (0.6%); 14 transient pain and discomfort at the level of the surgical incision (8%), 2 contractures of the lateral peroneal muscles (1.15%); 3 superficial infections (1.7%).	Retrospective nature, no control group, sample size. lack of objectively measurable parameters.
Pavone et al[1], 2018	68 (136 FFF) 12.7 yr (9-15 yr), mean follow-up 57.6 mo.	Calcaneo-stop.	AOFAS, Yoo Score, FADI, FADI Sport, OxAFQ-C scores at 1 and 3 yr. variation of the angles measured on X-ray images.	AOFAS (F 2, 201 = 287.51; P < 0.0001), Yoo Score (F 2, 201= 2627.00; P < 0.0001), OxAFQ-C (F2201 = 210.60; P < 0.0001), FADI (F 2, 201 = 372.62; P < 0.0001) and FADI Sport (F 2, 201= 189.32; P < 0.0001). Radiological assessments improved (P < 0.0001).	17 (12.5%); 5 pain at surgical scar (3.7%), 4 local symptoms at the incision (2.9%), 3 screw loosening (1.2%) and 4 superficial Infections (2.9%); 1 screw breakage (0.73).	Retrospective study. No control group. Mid-term follow-up. Lack of objectively measurable parameters.
Memeo et al[26], 2019	202 FFF, 13.6 yr (8-16 yr). Median follow-up was 130 mo (35-150 mo).	Calcaneo-stop.	Clinical evaluation, pain, and variation of the angles measured on X-ray images.	92% Percutaneous lengthening of the Achilles tendon. Improvement of clinical outcome, restoration of the medial arch and the hind foot valgus in orthostasis.	32 (15.8%): 23 (11.4%) incomplete correction; 9 (4.5%) screw breakages.	Retrospective study. No control group. Short-term follow-up. Lack of objectively measurable parameters.
Memeo et al[26], 2019	200 FFF, 12.8 yr (8 to 16 yr). Median follow-up 130 mo (35-150 mo).	Subtalar AR bioabsorbable device.	Clinical evaluation, pain, and variation of the angles measured on X-ray images.	71% Percutaneous lengthening of the Achilles tendon. Improvement of clinical outcome, restoration of the medial arch and the hind foot valgus in orthostasis.	25 (12.5%): 20 (10%) inflammatory process involving soft tissues around tarsal sinus; 5 (2.5%) device. removals and substitutes.	Retrospective study. No control group. Mid-term follow-up. Lack of objectively measurable parameters.
Megremis et al[18], 2019	14 (28 FFF), 10.71 ± 1.58 yr (range 8-14 yr). Mean follow-up duration of 35.14 ± 9.82 mo (19-60 mo).	Subtalar AR.	AOFAS pre- and postoperatively.	The mean postoperative AOFAS score was 88.851 (range 83-97) points (P < 0.0001).	No complication.	Retrospective study. No control group. Short-term follow-up. Lack of objectively measurable parameters.
Martinelli et al[14], 2018	49 (98 FFF) 10.7 yr (7-14 yr), mean follow-up 4.9 yr.	Subtalar AR.	CHQCF; OxAFQ pre- and postoperatively. Number of sessions per week.	The mean OxAFQ scores within the ‘Emotional’ (P < 0.05) and ‘footwear’ item (P < 0.05) (children), and in the ‘school and play’ (P < 0.05) and ‘footwear’ item for the parent scale. 44 (89%) parents were satisfied with the surgical procedure.	Three residual pain; 1 residual deformity, and one sport limitation. 3 subtalar implants removed because of pain at the sinus tarsi.	Retrospective nature; as some of the anthropological measures were not obtained before surgery.
Kubo et al[20], 2020	Group A (5-8 yr): 6 (11 FFF) MA 7.4 ± 1.2 yr; Group B (9-12 yr): 33 (63 FFF) MA: 11.2 ± 1.0 yr; Group C (13-15 yr): 11 (21 FFF). MA 13.6 ± 0.7 yr.	Calcaneo-stop.	CP; lat. TCA; a.p. TCA, kite angle; NCI; Meary angle. Bony maturation.	Improvement of radiological assessment in each group (P < 0.05). Best deformity correction when surgery was conducted between 9 and 12 yr, with significant improvement in all measured parameters without secondary deterioration during FU.	No complications.	Retrospective study; no clinical scores.
Indino et al[28], 2020	56 (112 FFF), 9-14 yr (MA 15.5 ± 1.2 yr), mean follow-up 40.1 ± 23.6 mo.	Subtalar AR.	AOFAS, SEFAS, SF-12.	AOFAS 97.3 ± 4.5, SEFAS 47.2 ± 1.5, SF-12.MCS 51.1 ± 8.8, SF-12.PCS 55.6 ± 9.1, Clinical scores were not correlated with the foot radiographic parameters at follow-up period.	No complications.	No preoperative clinical or functional scores.
Hsieh et al[15], 2019	102 (204 FFF) MA 9.1 ± 0.2 yr).	Subtalar AR.	CP; lat. TCA; a.p. TCA, kite angle; NCI; Meary angle.	22 cases of bilateral extrusion in the overweight group (39%) vs 13 cases bilateral extrusion in the low body weight group (23%) (P = 0.0004). The inter-observer correlation was 0.95. Improvement of radiological assessment at 3 mo postoperative follow-up (P < 0.05).	19%.	Retrospective nature, no control group, sample size. lack of objectively measurable parameters. No BMI loss evaluation surgical outcomes.
Hagen et al[32], 2019	7 (13 FFF), MA 12.43 ± 1.27 yr.	Calcaneo-stop.	Pedobarographic measurements before surgery, 3, 14, 28 d after.	The ground force increased significantly in lateral foot areas (P < 0.001) and decreased in medial areas (P < 0.001).	1 minor soreness.	Sample size, short follow-up.
Hagen et al[31], 2020	14 (27 FFF), MA 12.4 ± 1.4 yr.	Calcaneo-stop.	Heel angle, rearfoot angle, leg axis angle, step length, and walking speed, pre- and postoperatively.	Heel valgus (F 1, 24 = 110.465, P < 0.001); Dynamic heel angles vs static heel angles (F 1, 24 = 38.498, P < 0.001). Correlation between heel angle and rearfoot angle (static: r = 0.647, P < 0.001; dynamic: r = 0.640, P = 0.001). Dynamic rearfoot angle vs static rearfoot angle (F 1, 24 = 166.55, P < 0.001).	No complications.	Small size. No clinical assessment.
Giannini et al[21], 2017	44 (88 FFF). MA 11.7 yr (8-14 yr).	Bioabsorbable Calcaneo-stop.	Patient satisfaction; Meary angle; talocalcaneal angle.	33 excellent, 9 good outcome, and 2 poor clinical. Meary’s, talocalcaneal angle had improved (P < 0.001).	2 breakages.	Retrospective nature, no control group, sample size. lack of objectively measurable parameters.
Faldini et al[24], 2018	173 (283 FFF), MA 11.2 yr. MF 49.5 mo.	Bioabsorbable Calcaneo-stop.	FFI, SEFAS.	FFI score 4; SEFAS score 47.2, well into the normal range. No statistically significant differences between males and females (P value > 0.05).	3 implant breakages, 1 persistent pain secondary to a local inflammatory response.	No radiological assessment. No control group.
Caravaggi et al[33], 2018	13 (26 FFF), MA 11.3 ± 1.6 yr, MF 1 yr (12.5 ± 3.7 mo).	Endo-orthotic implant and Calcaneo-stop.	A 10-point VAS, Kinematic and kinetic analysis during normal walking, radiological parameters.	All radiological parameters and VAS were significantly improved at 1-yr follow-up (P < 0.001). No significant differences were detected in spatiotemporal and ground-reaction-force parameters between pre-op evaluation and control in either implant groups.	No complications.	Multisegment foot protocol. Small size. No clinical assessment.
Bernasconi et al[27], 2020	31 (62 FFF), MA 10.5 ± 1.6 yr, MF 62 ± 15 mo.	Subtalar AR.	ROM; AOFAS; VAS-FA, radiological parameters.	Improvement clinical score and radiological parameters except talonavicular coverage angle (P = 0.49) and calcaneo-fifth metatarsal angle (P = 0.53). Improvement of dorso-plantar view. No loss of correction was found after removal of the implant.	17 (24%) sinus tarsi syndromes.	Retrospective nature, no control group, sample size. lack of objectively measurable parameters.
Elmarghany et al[38], 2020	42 (84 FFF); MA 9.92 ± 2.2 yr; range (7-15 yr). MF 29.1 mo.	Calcaneo-stop.	AOFAS; radiological parameters.	Improvement clinical score and radiological parameters (P value < 0.000).	3 minor complications, 1 (0.02%) under correction. 1 sunken screw. 1 synovits around screw.	Retrospective nature, No control group, sample size. lack of objectively measurable parameters.

AOFAS: American Orthopedic Foot and Ankle Society; AR: Arthroereisis; FADI: Foot and Ankle Disability Index; FFF: Flexible flatfoot; FFI: Foot Function Index Questionnaire; MA: Mean age; MF: Mean follow-up; OxAFQ-C: Oxford Ankle Foot Questionnaire for Children; ROM: Range of motion; SEFAS: Self-reported Foot and Ankle Score; VAS: Visual Analogue score.