EVALUATION OF A TRI-COMPARTMENT OFFLOADER KNEE BRACE: A PROSPECTIVE STUDY IN INDIVIDUALS WITH KNEE OSTEOARTHRITIS

ABSTRACT

Purpose: Knee Osteoarthritis (KOA) is a leading cause of physical disability worldwide. Individuals who suffer from KOA experience pain, reduced mobility, and lower quality of life. Considering the upward trend in KOA diagnoses, the economic burden of knee replacement, and the surgical backlog from COVID-19, the need for alternative conservative treatments is pressing. Bracing is an economical and accessible form of conservative treatment. Traditional KOA braces only offload one knee compartment. However, over 50% of the KOA population suffers from cartilage damage in multiple compartments. The Levitation™ “Tri-Compartment Offloader” (TCO) knee brace contains embedded liquid springs that provide flexion support and extension assist to simultaneously offload joint forces in all three knee compartments. Similar to the effect of weight loss, biomechanical studies have demonstrated that the TCO provides clinically relevant reductions in tibiofemoral and patellofemoral joint contact forces ranging between 30-50%. However, there is a need to validate whether the TCO improves real world outcomes in KOA patients. Therefore, the current objective is to examine the influence of a TCO brace on knee pain and function in a population suffering from KOA. Methods: Individuals with KOA who purchased the TCO are being enrolled in the ongoing study following informed consent (n=113). Participants receive 4 online surveys administered using Qualtrics (USA). The first survey is completed before brace wear commences (0-months), and follow-up surveys are scheduled after 1-month, 3-months and 9-months of TCO brace wear. The surveys contain validated questionnaires including the Visual Analog Scale (VAS) for pain, Knee Injury and Osteoarthritis Outcome Score (KOOS), EuroQol 5D-5L, International Physical Activity Questionnaire, Orthotics and Prosthetics Users Survey;as well as custom questionnaires to collect demographic information. This preliminary analysis includes 54 participants who completed the 1-month and 3-months surveys (mean age 55.7±9.1 yrs;43 male). Variables of interest include knee pain (VAS) and function (KOOS). Pain was assessed during four common activities 1) walking on a flat surface (Flat Walking);2) rising from seated (Sit & Stand);3) going up and down stairs (Stairs);and 4) Squatting. A VAS pain score of 0 represents no pain, and 100 represents the worst pain imaginable. KOOS domains included 1) Pain;2) Symptoms;3) function in activities of daily living (ADL);4) function in sport and recreation (S&R);and 5) knee-related quality of life (QoL). A KOOS score of 0 represents severe problems, and 100 represents no problems. Statistical analysis was conducted using SPSS (IBM, USA). Pain (VAS score) between timepoints was assessed using four one-way repeated measures ANOVAs with Bonferroni correction for multiple comparisons (α = 0.0125). Post-hoc analyses were used to compare timepoints. Effects of TCO use on knee function were assessed using Wilcoxon's signed-rank test with Bonferroni correction (α = 0.01). Results: Participants wore the TCO for an average of 5.1±3.4 hours/day, and 5.2±1.8 days/week at 1-month and 5.0±3.1 hours/day and 4.9±1.7 days/week at 3-months. One participant did not complete the 1-month survey. Further, two participants did not provide complete VAS responses (Table 1) and a number of participants did not provide answers to all KOOS domains (Table 2). Significant effects of TCO use on pain were observed during all activities (p<0.001) (Figure 1, Table 1). Post-hoc analyses indicated significantly decreased pain for all activities at 1-month (p <0.001) and 3-months (p-value range 0.001-0.01) compared to baseline (0-months). There were no significant differences in pain between 1-month and 3-months of TCO use (p-value range 0.318-1). The scores for all 5 domains of KOOS increased after 1-month and 3-months of TCO brace wear compared to baseline. TCO use resulted in a significant increase in ADL (0-1 months p<0.001;0-3 months p<0.001), Pain (0-1 months p<0.001), and S&am ;R (0-1 months p<0.002) (Figure 2, Table 2). [Formula presented] [Formula presented] [Formula presented] [Formula presented] Conclusions: This study demonstrates that the TCO brace significantly decreased knee pain for KOA patients when worn during common daily activities. The mean difference in pain scores after 1-month of TCO wear was greater than the minimally clinically important difference (-19.9mm) for all activities suggesting a clinically significant improvement in pain. These significant reductions in pain were maintained after 3-months of TCO wear, demonstrating continued pain management benefits at 3-months. This suggests that the TCO is an effective conservative treatment option over a moderate period of time. Brace usage data indicated good compliance and consistent duration of brace wear between 1-month and 3-months, which could be a result of the continued reduction in knee pain. An improvement in all 5 dimensions of KOOS was also observed, with significant improvements in Pain, ADL, and S&R after 1-month of wearing the TCO. These findings indicate that the Levitation™ TCO brace has a strong potential to manage pain and improve knee function for patients suffering from KOA. Future work includes continued data collection and investigating the effects of the TCO on pain and function in the KOA population over a longer time period.