Introduction: Clinical decisions are often made on weight-bearing radiographs. However, it is unknown whether various weight-bearing conditions alter specific radiographic measurements. The purpose of this study was to determine whether percentage weight-bearing influences radiographic measurements of the normal foot. Methods: A prospective study with 20 healthy individuals had radiographs of the foot under 5 weight-bearing conditions (non–weight-bearing, 10% body weight, 25% body weight, 50% body weight, and 100% body weight). Measurements were made of hallux valgus angle (HVA), 1-2 intermetatarsal angle (IMA), talonavicular coverage angle (TNCA), talocalcaneal angle (TCA), forefoot width, LisFranc distance, cuboid height to ground (CHG), and talo–first metatarsal angle (TMA) of each weight-bearing condition. Statistical differences of each measurement for each weight-bearing condition were determined. Results: The TNCA and TCA increased significantly, whereas the CHG decreased significantly with increased percentage body weight. There were no differences in HVA, IMA, forefoot width, LisFranc distance, and TMA with increased percentage body weight. Conclusions: This study shows an increase in TNCA and TCA, and decrease in CHG, demonstrating a flattening of the medial arch, increasing hindfoot valgus, and midfoot external rotation and abduction with increasing percentage body weight applied to a foot. Percentage weight-bearing does not change radiographs in the foot between 25% and 100% weight-bearing. The clinical relevance of this finding is that graduated postinjury or postoperative weight-bearing regimens may only be relevant if the patient is either less than or greater than 25% of body weight on their extremity. Levels of Evidence: Case Series, Level IV: Prospective

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Background The repair of osteochondral lesions remains a challenge due to its poor vascularity and limited healing potential. Micronized cartilage matrix (MCM) is dehydrated, decellularized, micronized allogeneic cartilage matrix that contains the components of native articular tissue and is hypothesized to serve as a scaffold for the formation of hyaline-like tissue. Our objective was to demonstrate in vitro that the use of MCM combined with mesenchymal stem cells (MSCs) can lead to the formation of hyaline-like cartilage tissue in a single-stage treatment model. Design In group 1 (no wash), 250 µL MCM was reconstituted in 150 µL Dulbecco's phosphate-buffered saline (DPBS) for 5 minutes. Group 2 (saline wash) included 250 µL MCM washed in 20 mL DPBS for 30 minutes, then aspirated to remove all DPBS and reconstituted in 150 µL DPBS. Group 3 (serum wash): 250µL MCM washed in 20 mL DPBS for 30 minutes, then aspirated and reconstituted in 150 µL fetal bovine serum. Each group was then added to 50 µL solution of MSC suspended in DPBS at a concentration of 1.2 × 10 cells/350 µL. After 3 weeks, the defects were extracted and sectioned to perform viability and histologic analyses. Results Stem cells without rehydration of the MCM showed almost no viability whereas near complete cell viability was seen after rehydration with serum or saline solution, ultimately leading to chondrogenic differentiation and adhesion to the MCM particles. Conclusion We have shown in this proof-of-concept in vitro study that MCM can serve as a scaffold for the growth of cartilage tissue for the treatment of osteochondral lesions.

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