Biofreeze® vs. a Placebo on Knee Osteoarthritis Walking Gait Characteristics and Pain

The purpose of this study is to determine the effect of Biofreeze® versus a placebo on walking gait characteristics and pain during walking in individuals with bilateral knee osteoarthritis (OA).

A convenience sample of 20 participants, >40 years with previously diagnosed bilateral KOA were recruited. Participants must have been diagnosed with bilateral knee OA and be able to perform all study procedures. All participants reported in comfortable clothing and sneakers. After explanation of the study and consent, participants completed the demographics questionnaire, Numeric Pain Rating Scale (NPRS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and knee function survey. Participants then completed a 3mph 3-minute walking baseline assessment. Following the assessment, participants rated their pain and were randomly assigned to receive a blinded topical of either Biofreeze® or a Placebo. The dose of both gels was 5 mL per knee. The participant then waited 15 minutes, rated their pain, and repeated the 3-minute walking assessment and rated their pain once more. There was a minimum of a 24-72-hour washout period after which time the participants repeated the same protocol using the other topical.

Participants will be randomly assigned 1 of 2 topicals, Gel A or Gel B. Upon completion of study procedures they will return for a second testing session and receive the other topical.

The Biofreeze® gel will contain 3.5% menthol while the placebo will be the same formula with menthol removed and a menthol fragrance added so it is non-distinguishable from the real Biofreeze® gel. The dose of both gels will be 5 mL per knee, which is consistent with previous studies who reported a treatment effect for topical gels containing menthol (1 mL of gel for every 200 cm2 of surface area). The treatment will be applied by the investigator using a gloved hand and syringe containing 5mL of gel. The gel will be applied to the anterior and posterior knee from superior patella to the quadriceps insertion over a period of 5 seconds. The participant will wait 15 minutes, rate the pain in their knees.

The Biofreeze® gel will contain 3.5% menthol while the placebo will be the same formula with menthol removed and a menthol fragrance added so it is non-distinguishable from the real Biofreeze® gel. The dose of both gels will be 5 mL per knee, which is consistent with previous studies who reported a treatment effect for topical gels containing menthol (1 mL of gel for every 200 cm2 of surface area). The treatment will be applied by the investigator using a gloved hand and syringe containing 5mL of gel. The gel will be applied to the anterior and posterior knee from superior patella to the quadriceps insertion over a period of 5 seconds. The participant will wait 15 minutes, rate the pain in their knees

Biofreeze is a topical analgesic that uses the cooling effect of menthol, a natural pain reliever, to soothe minor muscle and joint pain. The product will be applied immediately after walking. The participant will wait 15 minutes prior to walking again.

The placebo is the Biofreeze product with all active ingredients removed. The product will be applied immediately after walking. The participant will wait 15 minutes prior to walking again.

Pain will be measures on a scale of 0 to 10, 0 being no pain at all and 10 representing the worst imaginable pain.

Pain will be measured at baseline, immediately following the 3 minute walk, 15 minutes after topical application, and after the second 3 minute walk for both topical applications

Knee Flexion Range of Motion will be measured using the Woodway Walker View Treadmill which utilizes a 3D camera and will be measured during the last 30 seconds of the 3 minute walk.

Knee Flexion Range of Motion will be measured for both topical applications at initial walk and post-topical walk. The session will last a total of 30 minutes.

Hip Flexion Range of Motion will be measured using the Woodway Walker View Treadmill which utilizes a 3D camera and will be measured during the last 30 seconds of the 3 minute walk.

Knee Flexion Range of Motion will be measured for both topical applications at initial walk and post-topical walk. The session will last a total of 30 minutes

Step Length will be measured using the Woodway Walker View Treadmill which utilizes load cells within the treadmill belt and will be measured during the last 30 seconds of the 3 minute walk.

Knee Flexion Range of Motion will be measured for both topical applications at initial walk and post-topical walk. The session will last a total of 30 minutes

Inclusion Criteria: must have been diagnosed with bilateral knee osteoarthritis (OA) and be able to perform all study procedures Exclusion Criteria: less than 40 years of age, pregnancy, cancer, rheumatoid arthritis, a total or partial knee replacement, and/or a corticosteroid injection within the past 4 weeks