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Background: Ankle arthrodesis has historically been the standard of care for end-stage ankle arthritis; however, total ankle arthroplasty (TAA) is considered a reliable alternative. Our objective was to compare 3-dimensional foot and ankle kinetics and kinematics and determine the ankle power that is generated during level walking and stair ascent between TAA and ankle arthrodesis patients., Methods: Ten patients who underwent TAA with a modern fixed-bearing ankle prosthesis and 10 patients who previously underwent ankle arthrodesis were recruited. Patients were matched for age, sex, body mass index, time from surgery, and preoperative diagnosis. A minimum of 2-year follow-up was required. Patients completed instrumented 3D motion analysis while walking over level ground and during stair ascent. Between-group differences were assessed with a 2-tailed Mann-Whitney exact test for 2 independent samples., Results: Sagittal ankle range of motion (ROM) was significantly higher in the TAA group (21.1 vs 14.7 degrees, P = .003) during level walking. In addition, forefoot-tibia motion (25.3±5.9 degrees vs 18.6±5.1 degrees, P = .015) and hindfoot-tibia motion (15.4±3.2 degrees vs 12.2±2.5 degrees, P = .022) were significantly greater in the TAA group. During stair ascent, sagittal ankle ROM (25 vs 17.1 degrees, P = .026), forefoot-tibia motion (27.6 vs 19.6 degrees, P = .017), and hindfoot-tibia motion (16.8 vs 12 degrees, P = .012) was greater., Conclusion: There were significant differences during level walking and stair ascent between patients with TAA and ankle arthrodesis. TAA patients generated greater peak plantarflexion power and sagittal motion within the foot and ankle compared to patients with an ankle arthrodesis. Further investigation should continue to assess biomechanical differences in the foot and ankle during additional activities of daily living., Level of Evidence: Level III, comparative study.

Background: A proximal phalangeal dorsiflexion osteotomy (Moberg osteotomy) is commonly used to treat hallux rigidus, but the mechanical explanation for its effectiveness is unclear. The purpose of our study was to test the effect of a Moberg osteotomy on first metatarsophalangeal joint contact mechanics., Methods: Ten cadaveric first ray specimens were dissected, with the medial band of the plantar aponeurosis preserved at its origin, and placed in a custom testing apparatus. Forefoot loads during mid-stance with the first metatarsal positioned at 10 degrees were simulated using a custom-made loading jig while contact mechanics were acquired with a thin pressure-sensitive sensor. A Moberg osteotomy was performed starting 9 mm distal to the proximal phalanx with excision of a 3-mm wedge of bone and fixated with a 2-mm Kirschner wire. The effect of the Moberg osteotomy was tested by reapplying the forefoot loads and acquiring the joint pressures. The center of pressure, peak pressure, and contact area were calculated. Paired t tests were performed to determine if the Moberg osteotomy affected joint contact mechanics., Results: The Moberg osteotomy shifted the center of contact pressure on the proximal phalanx surface more plantarly (P < .01). However, the Moberg osteotomy did not affect the peak pressure (P = .62) or the joint contact area (P = .96)., Conclusions: There were no differences in peak pressure or first MTPJ contact area, but a plantar shift in the center of pressure occurred after the Moberg osteotomy., Clinical Relevance: The plantar cartilage, which is often spared from arthritic changes, may be preferentially loaded and the potential edge loading following cheilectomy may be avoided with the Moberg osteotomy secondary to the plantar shift of center of pressure., (© The Author(s) 2015.)

Background: The relationship between turf toe and plantar foot pressures has not been extensively studied. Two hypotheses were tested in a cohort of professional American football players: first, that a history of turf toe is associated with increased peak hallucal and first metatarsophalangeal (MTP) plantar pressures; second, that decreased range of motion (ROM) of the first MTP correlates with increased peak hallucal and first MTP plantar pressures., Materials and Methods: Forty-four athletes from one National Football League (NFL) team were screened for a history of turf toe during preseason training. Dorsal passive MTP ROM and dynamic plantar pressures were measured in both feet of each player. Anatomical masking was used to assess peak pressure at the first MTP and hallux., Results: First MTP dorsiflexion was significantly lower in halluces with a history of turf toe (40.6 +/- 15.1 degrees versus 48.4 +/- 12.8 degrees, p = 0.04). Peak hallucal pressures were higher in athletes with turf toe (535 +/- 288 kPa versus 414 +/- 202 kPa, p = 0.05) even after normalizing for athlete body mass index (p = 0.0003). Peak MTP pressure was not significantly different between the two groups tested. First MTP dorsiflexion did not correlate with peak hallucal or first MTP pressures., Conclusion: This study showed that turf toe is associated with decreased MTP motion. In addition, increased peak hallucal pressures were found. Further study is warranted to determine whether these pressures correlate with the severity of symptoms or progression of turf toe to first MTP arthritis.