Subtalar arthroereisis with HyProCure-I implant yields good results in progressive collapsing Foot Deformity

In Progressive Collapsing Foot Deformity one surgical option in order to balance the hindfoot is to stabilize the talus on the calcaneus by means of a subtalar arthroereisis. An implant is placed into the sinus tarsi/tarsal canal with the hindfoot in a reduced position. The principle of all sinus tarsi implants is to block hyperpronation without restricting natural pronation.

Martin Ålund conducted a study to report the mid-term incidence and causes for implant removal, patient-reported outcomes, and radiographical results in patients treated with subtalar arthroereisis. This study was conducted at Department of Orthopaedic Surgery, Sahlgrenska University Hospital¸ Gothenburg, Västra Götaland County, Sweden. It has been published in ‘Journal of Foot and Ankle Surgery (Asia-Pacific).’

Martin Ålund prospectively collected data from 40 cases in 37 patients and analyzed it. Subtalar arthroereisis was performed with a HyProCure-I implant as a single procedure in 19 cases and as an adjuvant procedure in 21 cases. In all cases, a Self-reported Foot and Ankle Score (SEFAS) were completed preoperatively. At the final follow-up, SEFAS was available in 32 cases. Standard weightbearing lateral and anteroposterior (AP) radiographs were obtained preoperatively in all cases and at final follow-up in 29 cases.

Key findings of the study were:

• A total of 40 procedures were performed on 37 patients, of whom 10 were male with a mean age of 51.5 years, and 27 were female with a mean age of 44 years.

• The average follow-up time was 46 (range 35–60) months.

• The implant was removed in four single procedure cases and four combined procedure cases (20%).

• The average time between implantation and removal was 20 (range 2–54) months.

• Causes for pain leading to implant removal are discussed.

• Patient satisfaction in the remaining 32 cases was similar in both groups.

• Mean SEFAS improvement was 14.5 points [95% confidence interval (CI), 10.6–18.5] in the single procedure group and 17.2 points (95% CI, 12.0–22.3) in the combined procedure group.

• Similar radiographical improvements were noted in the two groups.

Martin Ålund commented – “In conclusion, subtalar arthroereisis seems to be effective in the treatment of Progressive Collapsing Foot Deformity, both as a standalone and an adjunctive procedure. In either case, careful patient selection is needed. When performed in a nonobese patient with a functionally intact PT tendon and a stable medial column, a standalone subtalar arthroereisis may achieve good subjective and functional results from a mid-term perspective. In all other cases, the implant alone will most likely not do the job in terms of maintaining hind- and midfoot balance. If medial column instability is not taken care of, the demands on the sinus tarsi implant will simply be too great. Consequently, the implant fails to keep the arch up, and adjunctive procedures must be performed. More studies need to be conducted in order to further outline the proper technique and correct sizing of the implant. Both are critical for the maintenance of the correction initially achieved and for long-term patient tolerance.”

Further reading:

Subtalar Arthroereisis as a Surgical Option in the Reconstruction of Progressive Collapsing Foot Deformity: A Prospective 3-year Follow-up Study on Patient Satisfaction and Causes for Implant Removal in 40 Cases Treated with the HyProCure Implant

Martin Ålund

Journal of Foot and Ankle Surgery (Asia-Pacific) 2023;10(2):92–101.