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Observational studies have shown correlations between intramyocellular lipid (IMCL) content and muscle strength and contractile function in people with metabolically abnormal obesity. However, a clear physiologic mechanism for this association is lacking, and causation is debated. We combined immunofluorescent confocal imaging with force measurements on permeabilized muscle fibers from metabolically normal and metabolically abnormal mice and people with metabolically normal (defined as normal fasting plasma glucose and glucose tolerance) and metabolically abnormal (defined as prediabetes and type 2 diabetes) overweight/obesity to evaluate relationships among myocellular lipid droplet characteristics (droplet size and density) and biophysical (active contractile and passive viscoelastic) properties. The fiber type specificity of lipid droplet parameters varied by metabolic status and by species. It was different between mice and people across the board and different between people of different metabolic status. However, despite considerable quantities of IMCL in the metabolically abnormal groups, there were no significant differences in peak active tension or passive viscoelasticity between the metabolically abnormal and control groups in mice or people. Additionally, there were no significant relationships among IMCL parameters and biophysical variables. Thus, we conclude that IMCL accumulation per se does not impact muscle fiber biophysical properties or physically impede contraction. Article Highlights: Excess intramyocellular lipid (IMCL) could physically disrupt sarcomere contraction by pushing myofibrils apart, increasing myofilament stiffness, or changing cytoplasmic viscoelasticity. We used isolated, permeabilized myofibers from metabolically normal and metabolically abnormal mice and people with metabolically normal and abnormal obesity to evaluate the relationships among IMCL lipid droplet characteristics and myofiber mechanics. We found fiber type–specific differences in IMCL accumulation among species and metabolic status but no relationships among any IMCL parameters and myofiber biophysical properties. If IMCL directly impairs muscle contraction, it is not through physical disruption of sarcomeres or cytoplasmic composition. [ABSTRACT FROM AUTHOR]

Background: The management of symptomatic osteochondral lesions of the talus (OLTs) previously treated with arthroscopy is controversial. Minimal data exist on the role for repeat arthroscopy. Here, we describe our experience with repeat arthroscopy and microfracture for symptomatic OLTs. Methods: Our database was queried over an 8-year period to identify patients undergoing repeat arthroscopy and microfracture as treatment for symptomatic OLTs. Phone surveys were conducted to assess residual pain, patient satisfaction, and need for subsequent surgery. We compared patient outcomes based on the size of their OLT (small lesions ≤150 mm2, large >150 mm2) and the presence or absence of subchondral cysts. Results: We identified 14 patients who underwent repeat arthroscopy and microfracture for symptomatic OLTs. Patients reported reasonable satisfaction (7.6 ± 3.5 out of 10) but moderate residual pain (4.7 ± 3.4 out of 10) at midterm follow-up (5.1 ± 2.9 years). In total, 21% (3/14) of patients had undergone subsequent surgery. Patients with small (n = 5) and large OLTs (n = 9) had similar postoperative pain scores (4.2 ± 4.1 vs 4.9 ± 3.2) and postoperative satisfaction levels (6.4 ± 4.9 vs 8.3 ± 2.5). Conclusion: At midterm follow-up, repeat arthroscopy for symptomatic OLTs demonstrated reasonable satisfaction but moderate residual pain. Lesion size or presence of subchondral cysts did not affect outcome, but our sample size was likely too small to detect statistically significant differences. These data show that repeat ankle arthroscopy can be performed safely with modest outcomes, and we hope that this report aids in managing patient expectations. Level of Evidence: Level IV Case Series [ABSTRACT FROM AUTHOR]

Abstract Background Knee or tibiotalocalcaneal arthrodesis is a salvage procedure, often with unacceptable rates of nonunion. Basic science of fracture healing suggests that compression across a fusion site may decrease nonunion. A novel ratcheting arthrodesis nail designed to improve dynamic compression is mechanically tested in comparison to existing nails. Methods A novel ratcheting nail was designed and mechanically tested in comparison to a solid nail and a threaded nail using sawbones models (Pacific Research Laboratories, Inc.). Intramedullary nails (IM) were implanted with a load cell (Futek LTH 500) between fusion surfaces. Constructs were then placed into a servo-hydraulic test frame (Model 858 Mini-bionix, MTS Systems) for application of 3 mm and 6 mm dynamic axial displacement (n = 3/group). Load to failure was also measured. Results Mean percent of initial load after 3-mm and 6-mm displacement was 190.4% and 186.0% for the solid nail, 80.7% and 63.0% for the threaded nail, and 286.4% and 829.0% for the ratcheting nail, respectively. Stress-shielding (as percentage of maximum load per test) after 3-mm and 6-mm displacement averaged 34.8% and 28.7% (solid nail), 40.3% and 40.9% (threaded nail), and 18.5% and 11.5% (ratcheting nail), respectively. In the 6-mm trials, statistically significant increase in initial load and decrease in stress-shielding for the ratcheting vs. solid nail (p = 0.029, p = 0.001) and vs. threaded nail (p = 0.012, p = 0.002) was observed. Load to failure for the ratcheting nail; 599.0 lbs, threaded nail; 508.8 lbs, and solid nail; 688.1 lbs. Conclusion With significantly increase of compressive load while decreasing stress-shielding at 6-mm of dynamic displacement, the ratcheting mechanism in IM nails may clinically improve rates of fusion.

Background: Ankle sprains are the most common musculoskeletal injury in the United States. Chronic lateral ankle instability can ultimately require operative intervention to decrease pain and restore stability to the ankle joint. There are no anatomic studies investigating the vascular supply to the lateral ankle ligamentous complex. Purpose: To define the vascular anatomy of the lateral ligament complex of the ankle. Study Design: Descriptive laboratory study. Methods: Thirty pairs of cadaveric specimens (60 total legs) were amputated below the knee. India ink, followed by Ward blue latex, was injected into the peroneal, anterior tibial, and posterior tibial arteries to identify the vascular supply of the lateral ligaments of the ankle. Chemical debridement was performed with 8.0% sodium hypochlorite to remove the soft tissues, leaving casts of the vascular anatomy intact. The vascular supply to the lateral ligament complex was then evaluated and recorded. Results: The vascular supply to the lateral ankle ligaments was characterized in 56 specimens: 52 (92.9%) had arterial supply with an origin from the perforating anterior branch of the peroneal artery; 51 (91.1%), from the posterior branch of the peroneal artery; 29 (51.8%), from the lateral tarsal branch of the dorsalis pedis; and 12 (21.4%), from the posterior tibial artery. The anterior branch of the peroneal artery was the dominant vascular supply in 39 specimens (69.6%). Conclusion: There are 4 separate sources of extraosseous blood supply to the lateral ligaments of the ankle. In all specimens, the anterior talofibular ligament was supplied by the anterior branch of the peroneal artery and/or the lateral tarsal artery of the dorsalis pedis, while the posterior talofibular ligament was supplied by the posterior branch of the peroneal artery and/or the posterior tibial artery. The calcaneofibular ligament received variable contributions from the anterior and posterior branches of the peroneal artery, with few specimens receiving a contribution from the lateral tarsal or posterior tibial arteries. Clinical Relevance: Understanding the vascular anatomy of the lateral ligament complex is beneficial when considering surgical management and may provide insight into factors that lead to chronic instability. [ABSTRACT FROM AUTHOR]

Background: Identifying preoperative risk factors that may portend poorer operative outcomes remains a topic of current interest. In hip and knee arthroplasty patients, the presence of patient-reported allergies (PRAs) has been associated with worse pain and function after joint replacement. However, these results have not been replicated across studies, including in shoulder arthroplasty cases. The impact of PRAs on foot and ankle outcomes has yet to be studied. The purpose of our study was to evaluate whether PRAs influence patient-reported outcome in foot and ankle surgery. Methods: To determine if PRAs are linked to poorer operative outcomes, we retrospectively identified 159 patients who underwent elective foot and ankle surgery. PRA data were obtained via chart review, and patient-reported outcomes were assessed preoperatively and postoperatively via multiple domains, including Patient Reported Outcome Measurement Information System (PROMIS) physical function, pain interference, and depression measures. Consistent with prior methodology, we compared outcome measures (preoperative, postoperative, and the change in outcome scores) between patients without self-reported allergies to patients with at least 1 PRA. Results: There were 159 patients studied; 79 patients had no allergies listed, and 80 patients had at least 1 PRA. Of the 80 patients with at least 1 PRA, there were a total of 170 possible allergies. There were no differences in preoperative, postoperative, or the change in outcome scores for all PROMIS measures (physical function, pain interference, and depression; P > .05) between patients with at least 1 PRA and those patients without any listed PRAs. Conclusions: We were unable to prove our hypothesis that PRAs were linked to poorer patient-reported outcomes following foot and ankle surgery. Closer review of the published reports linking PRAs to worse total joint arthroplasty outcomes revealed data that, while statistically significant, are likely not clinically relevant. Our negative findings, then, may in fact parallel prior studies on hip, knee, and shoulder arthroplasty patients. The presence of PRAs does not appear to be a risk factor for suboptimal outcomes in foot and ankle surgery. Level of Evidence: Level III, comparative series. [ABSTRACT FROM AUTHOR]