Claw Toe: Anatomic Guide for Injection of Botulinum Toxin into Foot Muscles

A systematic review of the claw toe deformity: What is known and what is needed apart from surgical procedures

The claw toe deformity is a painful condition that mainly affects the adult population. Although there are many different treatments to solve the deformity, there is no optimal procedure to restore the normal foot mechanics. The objective of this review was to identify the technical features of the kinematic evaluation methods used in patients with claw toes. Furthermore, the aim of this review was to clarify what is known and what is needed apart from the surgical procedures to correct the claw toe deformity, with the purpose of reducing risk factors of falling in elderly people. A search in electronic databases, such as Scopus (n = 78), Google Scholar (n = 705) and ScienceDirect (n = 290) was conducted. There were seven articles (43.75%) related to the fixation (arthrodesis) of proximal and distal interphalangeal joints, one article (6.25%) describes the correction of the claw toe through plantar plate tenodesis and release of collateral ligaments, four articles (25%) describe the procedure of tendon transfer, one article (6.25%) describes flexor digitorum brevis tenotomy and a proximal interphalangeal joint arthrolysis, and another article (6.25%) presented the impact of partial phalanx osteotomy to treat the claw toe deformity. In conclusion, the review indicates that there are several studies related to the treatment or correction of claw toe deformity. However, there is a lack of knowledge of the postsurgical effects of treating claw toe condition, especially in the structural mechanics (plantar pressure distribution, stability, gait, foot mechanics and so on) of the foot after the correction of the claw toe deformity. The analysis of the foot mechanics after the correction of the claw toes has to be paramount to determine the benefits of the correction.

Effects of Flexor Digitorum Longus Muscle Anatomical Structure on the Response to Botulinum Toxin Treatment in Patients with Post-Stroke Claw Foot Deformity

(1) Background: The purpose of this retrospective case-control study was to determine the relationship between the control of toe movements by flexor hallucis longus (FHL) and flexor digitorum longus (FDL) muscles and the response to treatment with botulinum toxin (BoNT) in post-stroke patients with claw toe. (2) Methods: Subjects with stroke-related leg paralysis/spasticity and claw toes received multiple injections of BoNT (onabotulinumtoxin A) into the FHL or FDL muscles. We investigated the relationship between the mode of transmission of FHL and FDL muscle tension to each toe (MCT) and treatment outcome using the data of 53 patients who received 124 injections with clinically recorded treatment outcome. We also dissected the potential variables that could determine the treatment outcome. (3) Results: The effectiveness of BoNT treatment was significantly altered by FDL-MCT (OR = 0.400, 95% CI = 0.162–0.987, p = 0.047). Analysis of the response to the first BoNT injection showed an odds ratio of FDL-MCT of approximately 6.0 times (OR = 0.168, 95% CI = 0.033–0.857, p = 0.032). The more tibial the influence of the FDL muscle on each toe, the better the treatment outcome on the claw toe. (4) Conclusions: The anatomic relation between FDL muscle and each toe seems to affect the response to treatment with BoNT in post-stroke patients with claw toes.