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Background Lisfranc ligamentous injuries are complex, and their treatment, along with the preferred method of fixation, is controversial. Implementing a flexible synthetic augmentation device (fibertape) has been described as an alternative to traditional screw fixation. This biomechanical study evaluated two fibertape devices with interference screw fixation: InternalBrace, and InternalBrace with supplementary intercuneiform stabilization. Methods The diastasis and relative angular displacement between bones were measured at three midfoot joints in the Lisfranc articulation. Measurements were obtained for the pre-injured, injured, and post-fixation stages under static loading. Specimens then underwent stepwise increases in cyclic loading performed at 1 Hz and 100 cycles, at 100 N ground reaction force intervals from 500 to 1200 N to simulate postoperative loading, and then up to 1800 N to simulate high loads. Failure of fixation was defined as diastasis greater than 2 millimeters at the second-metatarsal – medial-cuneiform joint. Results InternalBrace specimens demonstrated failures in 3 of 9 (33%) specimens at cyclic loads of 1000 N. Conversely, InternalBrace with Supplementary Limb specimens had 1 failure at 1200 N. The difference in diastasis at the second metatarsal-medial cuneiform joint was statistically significant between the two groups at higher loads of 1600N (p = 0.019) and 1800N (p = 0.029). Conclusion The use of InternalBrace for ligamentous Lisfranc injuries appears to provide a biomechanically viable alternative for withstanding early postoperative protected weight bearing. Furthermore, the use of a supplementary limb in addition to the InternalBrace fibertape fixation method appears to enhance its biomechanical efficacy.

Category: Trauma; Basic Sciences/Biologics; Midfoot/Forefoot; Sports Introduction/Purpose: Lisfranc ligamentous injuries are complex. Controversy exists regarding their treatment and preferred method of fixation. Fixation methods employing a FiberTape device and interference screw fixation have been described as an alternative to traditional screw fixation. The purpose of this biomechanical study was to evaluate two methods of fixation utilizing interference screw fixation with FiberTape augmentation in a cadaveric model. Methods: 9 paired cadaveric feet (mid tibia/fibula) were separated into two groups based on fixation method: FiberTape alone and FiberTape with supplementary limb into the middle cuneiform via anchor. At three joints of the midfoot (second metatarsal - medial cuneiform, intermediate cuneiform - medial cuneiform, second metatarsal - intermediate cuneiform), the diastasis and relative angular displacement between bones in the coronal plane were measured for static and cyclic loading. Measurements were obtained for the native (pre-injured), injured, and post-fixation in static loading. Fixed specimens then underwent stepwise increases in cyclic loading performed at 1 Hz and 100 cycles, at 100 N intervals from 500 to 1800 N ground reaction force. The Achilles tendon was also loaded to simulate postoperative weightbearing. Failure of fixation was defined as diastasis at the second metatarsal - medial cuneiform joint greater than 2 millimeters. Results: FiberTape specimens demonstrated diastasis failures of 3 of 9 (33%) specimens at cyclic loads of 1000 N. Conversely, FiberTape with supplementary limb specimens all survived past this loading magnitude, with 1 failing at supraphysiologic loads (>1200 N). The difference in diastasis at the second metatarsal-medial cuneiform joint was statistically significant between the two groups at forces of 1600N (p = 0.019) and 1800N (p = 0.029). There were no significant differences between the other joint diastases and relative angular displacements. Conclusion: The use of FiberTape for fixation of ligamentous Lisfranc injuries appears to provide a biomechanically viable alternative for withstanding early post-operative protected weightbearing. Furthermore, the use of a supplementary limb in addition to the FiberTape fixation method appears to enhance its biomechanical efficacy under cyclic loading especially at higher loads.

Category: Ankle Introduction/Purpose: In an estimated 70% of cases of Adult Acquired Flatfoot Deformity (AAFD) reconstruction, the spring ligament is elongated and/or damaged. Spring ligament reefing can be performed through several techniques including augmentation with Fibertape devices. In addition, biomechanical studies have demonstrated its safety and suggest early weight bearing may be performed. The purpose of this study is to evaluate the outcomes of early weight bearing following flatfoot reconstruction with use of InternalBrace augmentation for spring ligament reefing when performed in combination with medical displacing calcaneal osteotomy (MCO) and FDL tendon transfer. Methods: From 2016-2018, 45 patients underwent flatfoot reconstruction (MCO, FDL transfer, and gastrocnemius recession) with spring ligament reefing and augmentation with the InternalBrace device. All surgeries were performed by the senior orthopaedic surgeons (PJJ & MCA). Institutional early post-operative weight bearing protocol involves weight bearing as tolerated in a splint with crutches for two weeks, transitioning at 2 weeks to a Cam boot with 1 wedge WBAT. At 4 weeks, the patient is weaned off crutches and recommended to start therapy restricting excessive eversion and concentrating on calf strengthening, gait, and ROM. At weeks 6-8 they are weaned from the Cam boot into lace up ASO and shoe with arch support. Data were recorded at 2 weeks, 6 weeks, 12 weeks, 6 months and at yearly intervals. Outcomes and complications were documented. Results: Of the 45 cases there were no complications related to early weight bearing. Radiographic bony union rate of the MCO was 100% (45/45). Moreover, there was no loss of fixation of either the FDL transfer or spring ligament reefing with InternalBrace augmentation with early weight bearing. Lastly, radiographic evaluation noted no loss of Meary’s talo-first metatarsal angle when comparing initial postoperative radiographic to their final follow up. Additional complications in our cohort included the following: removal of painful hardware (1, 2.22%), sural neuritis (2, 4.44%), superficial cellulitis (1, 4.44%), and delayed lateral wound healing (1, 2.22%). Conclusion: Preliminary data shows that early protected weight bearing after flatfoot reconstruction and augmentation of the spring ligament with the InternalBrace device is safe and demonstrates few complications and no early loss of correction.

Category: Diabetes, Hindfoot, Midfoot/Forefoot Introduction/Purpose: Neuroarthropathy is a progressively debilitating disease commonly affecting the lower extremity, which can lead to profound bone and joint destruction, limb deformity, and even amputation. While there are several causes, long- standing neuropathy is the most common. This leads to loss of protective sensation to the foot, which combined with repetitive micro-trauma as a result of physical activity can lead to bone and joint destruction of the lower extremity as well as major deformity. Currently there are no animal models of this disease process. The purpose of this study was to develop a novel rodent model of neuroarthropathy through the induction of the underlying neuropathic state combined with a treadmill running protocol that closely resembles local micro-trauma seen in humans. Methods: Following IAUCUC approval, 8 diet-induced obesity (DIO) C57BL/6 mice were obtained along with 6 non-obese C57BL/6 control mice. DIO mice were fed a high-fat diet (60% fat by kcal) ad libitum starting at the age of 6 weeks. Control mice were administered a standard low-fat diet (10% fat by kcal) ad libitum from birth. Starting at 14 weeks-old, all mice underwent a controlled, high-intensity cardiovascular training protocol using a rodent treadmill four times per week at 30 minute intervals. This was carried out for seven weeks including a one-week acclimation period. Speed, distance and time were held constant between groups. Weekly hind-paw sensory assessments were performed including von Frey filament and hotplate testing. Anteroposterior and mediolateral X-Rays were obtained at the beginning and conclusion of the study and radiographic analysis was performed bilaterally for all specimens. Lastly, histopathologic analysis was performed to assess musculoskeletal destructive changes to the hind-paw. Results: Baseline hotplate testing revealed that obese and non-obese mice did not differ in thermal response latency (p=0.53), however following the seven-week running protocol, obese mice demonstrated increased thermal response latency compared to controls (p=0.006). Von Frey filament testing in obese mice depicted significantly reduced hind-paw withdrawal reflexes compared to controls, both prior-to and following treadmill running (pConclusion: Obese, neuropathic animals, when challenged with a controlled exercise regimen designed to induce micro-trauma develop reliable sensory, radiographic, and histopathologic parameters reminiscent of neuroarthropathy in humans. Conversely, non-obese control animals, treated with the same exercise regimen, do not develop these neurodegenerative and musculoskeletal changes. Perhaps wild-type obese mice can be further characterized as a viable model for the development of idiopathic neuroarthropathy.

Category: Diabetes, Hindfoot, Midfoot/Forefoot, obesity Introduction/Purpose: In recent decades, the prevalence of obesity in the United States has increased dramatically. This can be attributed in-part to the high-fat “Western Diet”. Consequentially, the economic burden of obesity to the healthcare system has rapidly increased, accounting for more than 10 percent of all medical spending in America. Furthermore, with regards to orthopedics, obesity has been shown to be a strong risk factor for musculoskeletal pain, injury, and post-operative complications. The purpose of this study was to determine the effects of high intensity cardiovascular training and controlled dietary intake on body weight, body fat percentage (BFP), and bone mineral density (BMD) in obese and non-obese mice. These results will provide a better understanding of how to optimally facilitate weight loss in obese patients. Methods: Following IAUCUC approval, 8 diet-induced obesity (DIO) C57BL/6 mice were obtained along with 6 non-obese C57BL/6 control mice. DIO mice were fed a high-fat diet (60% fat by kcal) ad libitum starting at the age of 6 weeks. Control mice were fed a standard low-fat diet (10% fat by kcal) ad libitum from birth. Starting at the age of 14 weeks, all mice underwent a controlled high intensity cardiovascular training protocol using a treadmill four times per week at 30 minute intervals. This was carried out for seven weeks including a one-week acclimation period. Speed, distance, and time spent running were all constant between groups. Mouse body weights were recorded several times per week throughout the study. Additionally, BFP and BMD were obtained bi-weekly using dual energy X-ray absorptiometry (DEXA) to assess morphophysiological changes longitudinally. Results: Preliminary investigations with a controlled exercise regimen reveal that obese mice, when fed a high-fat diet, continue to gain weight rapidly despite high intensity cardiovascular training whereas control mice maintain their weight. Following the seven-week training period, control mice gained an average of 1.25 g (p=0.41), while DIO mice gained an average of 8.55 g (pConclusion: The results of this study support the hypothesis that a controlled exercise regimen alone is ineffective for facilitating weight loss. In fact, obese mice administered a high-fat diet actually gain weight despite undergoing a rigorous exercise program. Additionally, simple differences in dietary intake have significant effects on body weight, body fat percentage, and bone mineral density. This suggests that while exercise may play a small role in maintaining a normal weight, obesity is irreversible with exercise alone. Obese orthopedic patients should be counseled on dietary modifications before engaging in an exercise program.