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98 m a s s a g e & b o d y w o r k j a n u a r y / f e b r u a r y 2 0 2 0 technique MYOSKELETAL ALIGNMENT TECHNIQUES A Big-Toe Kink in the Kinetic Chain Addressing Hallux Limitus and Rigidus By Erik Dalton, PhD 1 2 3 A fundamental feature of the foot often missed in our assessments is fi rst-toe mobility, specifi cally the metatarsophalangeal (MTP) joint. The fi rst MTP joint should be able to extend as much as 65 degrees, but many people lack full range of motion due to osteoarthritis or injury (Image 1). Limited MTP dorsifl exion may not stop our clients from running around, but the lack of big-toe mobility means the body is forced to compensate further up the kinetic chain. By altering the foot's natural movement patterns, limited MTP dorsifl exion can lead to "mysterious" knee or hip pain and an unstable gait. Curl your toes and try to walk normally—the change in movement is clear. During the stance phase of gait, our toes dorsifl ex to help raise the arch and provide greater shock absorption. As the arch fl attens, the toes, plantar fascia, and associated muscles eccentrically contract via the windlass mechanism (Image 2). This action helps spring the person forward with greater propulsion during push-off. However, it only works when there is decent big-toe mobility. With the feet acting as springs, absorbing and transferring the forces of gravity, Arthritic and movement-challenged MTP joint. Anatomy of the windlass mechanism. Hallux valgus and infl amed bunion. it should be a remarkably effi cient system, but that's not always the case. SIGNS AND SYMPTOMS The stiff and painful osteoarthritic symptoms of hallux rigidus usually occur in older clients, but a sports injury such as turf toe may, in time, lead to reduced range of motion in young adults as well. According to a 2017 literature review, hallux rigidus affects one of every 45 middle-aged people and 35–60 percent of the population older than 65. 1 If the brain perceives threat, the joint may become painful in an attempt to offl oad gravitational stress. This is often the case with a hallux valgus toe, where a bunion forms as the long metatarsal bone shifts toward the inside of the foot and the phalanx bones angle toward the second toe (Image 3). As for hallux limitus, this condition typically begins with mild restriction of functional range of motion and little MTP joint arthrosis. For some people, however, the condition quickly progresses to hallux rigidus, with full-blown osteoarthritis and bone spurs greatly limiting motion. In this population, the windlass mechanism begins to fail, and the big toe becomes locked in a nonfunctional hallux rigidus position. Referring to big-toe restrictions, my mentor Philip Greenman, DO, stated: "If discovered at an early stage with minimal spurring and the ability to engage the windlass mechanism, I believe manual therapy and a specialized corrective exercise program can maintain that mobility and prevent progression of the deformity. By systematically increasing dorsifl exion at the fi rst metatarsal joint, infl ammation and protective muscle guarding may be reduced, leading to symptomatic improvement." 2 Metatarsophalangeal (MTP) joint painful in an attempt to offl oad gravitational Arch height increases Big toe dorsifl exes Plantar fascia tightens