Managing Pain in Patients With MTP Arthritis

Hallux rigidus is a degenerative disease of the first metatarsophalangeal (MTP) joint which affect 2.5% of people over the age of 50. As the arthritis progresses, patients pain levels increase and range of motion decreases. Non-operative management includes the use of NSAIDS, intra-articular injections, shoe modification, activity modifications, and physical therapy. Oral NSAID have been used extensively to reduce swelling and pain but have been found unsatisfactory in providing pain relief. Injections have been shown relieve pain in patients with grade 1 MTP arthritis. Shoe modifications and orthotics can modify the biomechanics of the MTP joint and thereby alleviate pain. Based on expert opinions, it seems the Morton extensions may alleviate pain but are also poorly tolerated by patients due to it's uncomfortable shape, coincidently leading to a low patient compliance rate.

VKTRY insoles were initially designed to increase ground force leading to a harder push off for faster running or higher jumping. To enable energy return the insole needed to be extremely rigid and therefore consists out of a full-length Carbon-Fiber base. Unexpectedly the Carbon fiber base makes this a highly rigid construct which will likely benefit those patients with MTP arthritis as it will take away much movement of the MTP joint, without having an uncomfortable shape, i.e. patients can use this insole in their own shoes, possibly leading to a higher patient compliance and, simultaneously, to better outcome. Even though this insole is being widely used by athletes, no one has explored its role for treating patients with MTP joint arthritis. Therefore, the aim of this study is to compare the VKTRY insole to the current Morton extension insoles in a blinded randomized controlled trial

Subject Enrollment:

Patients were introduced to the study by Foot and Ankle orthopaedic surgeons if they were identified as having hallux rigidis. If the patient agreed, an authorized member of the study staff went through the study in detail and addressed any questions the patients had. If the patient was willing to participate, informed consent was obtained. We emphasized that not participating in the study will not affect their care now or in the future.

Once informed consent was obtained, the patient was randomized into one of two groups.

* Morton Extensions along with current pain management protocol
* VKTRY insoles along with the current pain management protocol

Explanatory variables gathered:

1. Basic patient characteristics
2. Range of motion at 1st MTP joint
3. Hallux Rigidus severity grading

Patients were evaluated at the initial appointment, 2 weeks, 6 weeks, and 12 weeks following their initial appointment. The surveys were given to the patients during each evaluation time point.

Sample Size Calculation:

Based on power analysis to detect a minimal clinically important difference of 10.6 (+/- 4.6 SD) points in the PROMIS pain intensity score between patients using the Vktory carbon fiber insole and patients using Morton's extension insole with an overall two-tailed Type-1 rate of 5%, 80% statistical power and accounting for a 30% lost to follow up, we needed 14 patients in total.

Eligibility Criteria:
Inclusion Criteria:

1. Adult patients (over 18 years old) with MTP joint arthritis
2. Adults who were competent and able to consent on their behalf
3. Patients who were seen at Massachusetts General Hospital and Newton Wellesley Hospital

Exclusion Criteria:

1. Patients who had history of 1st MTP joint injection
2. Patients that have already used similar orthotics or had prior surgery to the foot
3. Patients who will be treated surgically