How To Treat Hallux Rigidus In Runners
- Volume 22 - Issue 4 - April 2009
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While runners may use less range of motion in the first MPJ than walkers, the magnitude of forces in running across this important joint cannot be overestimated. Until recently, it was not possible to measure joint moments within the foot during walking or running. Now, with multi-segment foot modeling, we will soon learn more about the forces transmitted within the medial column of the foot and the first MPJ.
For now, we can look at the ankle and compare the differences in forces that occur in walking versus running. Many investigators have studied forces or moments that occur at the ankle joint, and have found that there is an approximate 10-fold increase of internal joint moment during running as opposed to walking. This means that the internal structure of the joint (i.e. the articular cartilage) is subjected to a 10-fold increase of stress-strain during running activity.
The first MPJ is actually more complicated than the ankle since there is considerable frontal plane movement of the first metatarsal coupled with dorsiflexion of the hallux. No implant for the great toe joint is designed to allow this coupled movement in the same magnitude. Thus far, measurements have been in vivo and no implant has been tested under the vigorous conditions of running.
Given the lack of evidence of favorable outcomes with prosthetic joint implants for the treatment of hallux rigidus in running athletes, podiatrists should be cautious about using these devices in this patient population. Furthermore, when an implant fails, the options for salvage may end the career of the running athlete.
Pertinent Insights On Arthrodesis For Stage III And IV Hallux Rigidus
What was once a forbidden procedure for the active patient is now becoming the best option for the treatment of stage III and IV hallux rigidus. Out of all retrospective studies of surgical treatment of hallux rigidus, those utilizing arthrodesis of the first MPJ consistently show superior results and patient satisfaction in comparison to other surgical options.19-22
Concerns about fusion of the first MPJ in active individuals focus on alteration of gait mechanics, transfer of dorsiflexion moment to the hallux interphalangeal joint, loss of the windlass mechanism and an inability to wear elevated heel footwear. However, there is minimal evidence in the literature that any of these events actually occur to any significant level.
When it comes to studies of athletes, Bouché showed favorable results in his preliminary study published in 1996.23 Bouché has expanded his study to now include 40 active athletic patients who have achieved good to excellent results with arthrodesis of the first MPJ for painful hallux rigidus.24
Kinematic studies of patients who underwent arthrodesis of the first MPJ showed a significantly shorter step length as well as reduced ankle power and torque at push off.20 At the same time, Lombardi showed increased medial longitudinal arch height after fusion of the first MPJ.19
It is unclear whether the gait abnormalities are the result of fusion or are a long-term compensation of walking with a painful first MPJ that has not changed after surgery. The fact is that athletes who present for treatment of stage III and IV hallux rigidus have functioned with less than 10 degrees range of motion of the first MPJ for many years.
Fusion of this joint likely has little change on gait and compensation at this point. The primary effect of fusion is the elimination of pain, which has demonstrated significant positive patient satisfaction.