SLR - October 2020 - Sonia Simon

Transfer of Abductor Hallucis Tendon Combined with Scarf Osteotomy Versus Single Scarf Osteotomy in Moderate to Severe Hallux Valgus Deformity: A Comparative Retrospective Cohort Study

Reference: Xiong Y, Shen B, Hao C, Xiao K, Wang J, Fang Z. Transfer of Abductor Hallucis Tendon Combined with Scarf Osteotomy Versus Single Scarf Osteotomy in Moderate to Severe Hallux Valgus Deformity: A Comparative Retrospective Cohort Study. BMC Musculoskelet Disord. 2019;20(1):455. 

Scientific Literature Review 

Reviewed By: Sonia Simon, DPM
Residency Program: St. Joseph Medical Center - Houston, TX

Podiatric Relevance: Hallux valgus deformity is a condition foot and ankle surgeons are commonly seeing and treating surgically. The Scarf osteotomy has gained popularity due to its inherent biomechanical stability and ability for early weight bearing. In addition to the bunionectomy, a lateral soft tissue release is typically performed to reduce deformity and rebalance the first metatarsophalangeal joint. In this study the authors consider the importance of the abductor hallucis muscle in maintaining joint stability and improving deformity correction by proposing a unique technique of transferring the abductor hallucis, combined with the Scarf osteotomy, to improve outcomes compared with a single Scarf osteotomy method. 

Methods: This is a retrospective study comparing the effects of transfer of the abductus hallucis tendon combined with Scarf osteotomy versus Scarf osteotomy alone. Seventy-three patients (92 feet) with moderate to severe hallux valgus were treated surgically and assessed retrospectively by a single surgeon. Thirty-six patients were treated with the transfer and 37 were treated with Scarf osteotomy alone. In the transfer group, part of the abductor hallucis tendon was released and transferred to the dorsal aspect of the medial capsule. Prospective outcomes measured were intermetatarsal angle (IMA), hallux valgus angle (HVA), distal metatarsal articular angle (DMAA) and first metatarsophalangeal joint range of motion at predetermined intervals of 6, 12 and 24 months post-operatively. Clinical results were measured with the American Orthopaedic Foot and Ankle Society (AOFAS) score. 

Results: In this study, 36 patients treated with the transfer of the abductor hallucis combined with Scarf osteotomy had significantly decreased HVA at six months, 12 months and 24 months post-operatively as compared with the Scarf osteotomy cohort. There was no significant difference noted with IMA, DMAA and AOFAS between the two groups any time after surgery. Healing time was comparable between the two groups, within eight weeks. 

Conclusions: The abductor hallucis transfer group achieved good clinical results, while strengthening medial tension and developing dynamic reconstruction of medial soft tissue. However, a point of concern is the cause of a hallux varus due to abductor hallucis transfer, which the study mentions briefly. Follow up only took place for 24 months; long term results and possible residual abductor hallucis tendon rupture should be evaluated. To further illustrate the effectiveness of this technique a larger scale study with long term follow up needs to be performed. Based on this study, the new technique did not display better results for moderate to severe hallux valgus as compared with Scarf osteotomy alone. 

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