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Sheep and deer calcanei are finding increased use as models for studies of bone adaptation, including advancing understanding of how the strain (deformation) environment influences the ontogenetic emergence of biomechanically relevant structural and material variations in cortical and trabecular bone. These artiodactyl calcanei seem ideal for these analyses because they function like simply loaded short‐cantilevered beams with net compression and tension strains on the dorsal and plantar cortices, respectively. However, this habitual strain distribution requires more rigorous validation because it has been shown by limited in vivo and ex vivo strain measurements obtained during controlled ambulation (typically walking and trotting). The conception that these calcanei are relatively simply and habitually loaded 'tension/compression bones' could be invalid if infrequent, though biologically relevant, loads substantially change the location of the neutral axis (NA) that separates 'compression' and 'tension' regions. The effect on calcaneus strains of the tension members (plantar ligament and flexor tendon) is also not well understood and measuring strains after transecting them could reveal that they significantly modulate the strain distribution. We tested the hypothesis that the NA location previously described during simulated on‐axis loads of deer calcanei would exhibit limited variations even when load perturbations are unusual (e.g. off‐axis loads) or extreme (e.g. after transection of the tension members). We also examined regional differences in the predominance of the three strain modes (tension, compression, and shear) in these various load conditions in dorsal, plantar, medial, and lateral cortices. In addition to considering principal strains (tension and compression) and maximum shear strains, we also considered material‐axis (M‐A) shear strains. M‐A shear strains are those that are aligned along the long axis of the bone and are considered to have greater biomechanical relevance than maximum shear strains because failure theories of composite materials and bone are often based on stresses or strains in the principal material directions. We used the same load apparatus from our prior study of mule deer calcanei. Results showed that although the NA rotated up to 8° medially and 15° laterally during these off‐axis loads, it did not shift dramatically until after transection of all tension members. When comparing results based on maximum shear strain data vs. M‐A shear strain data, the dominant strain mode changed only in the plantar cortex – as expected (in accordance with our a priori view) it was tension when M‐A shear strains were considered (shear : tension = 0.2) but changed to dominant shear when maximum shear strain data were considered (shear : tension = 1.3). This difference leads to different conclusions and speculations regarding which specific strain modes and magnitudes most strongly influence the emergence of the marked mineralization and histomorphological differences in the dorsal vs. plantar cortices. Consequently, our prior simplification of the deer calcaneus model as a simply loaded 'tension/compression bone' (i.e. plantar/dorsal) might be incorrect. In vivo and in finite element analyses are needed to determine whether describing it as a 'shear‐tension/compression' bone is more accurate. Addressing this question will help to advance the artiodactyl calcaneus as an experimental model for bone adaptation studies. [ABSTRACT FROM AUTHOR]

We tried to reduce our rate of conversion from index knee arthroscopy to total knee arthroplasty (TKA) for degenerative pathology (primarily meniscal) in the setting of coexisting arthritis in patients 50 years or older. We hypothesized that, by using a 2-surgeon independent evaluation method, we could reduce the rate to less than 10% by 3-year follow-up. Forty-two consecutive patients were initially evaluated by the knee replacement surgeon to determine if they were TKA candidates. They were then independently evaluated by another surgeon regarding the need for TKA and the possibility of arthroscopic debridement. The data showed a tendency: The under-10% target rate was nearly reached in patients younger than 65 years (12%; 2/17) but not in patients older than 65 years (36%; 9/25). The overall rate of conversion to TKA was 26%. The 2 main groups (arthroscopy only, arthroscopy-plus-TKA) did not differ in all measured characteristics. Failure of our method to achieve better outcomes demonstrates that conventional criteria are poor in predicting which patients with meniscal pathology, which is believed to be relatively more symptomatic than coexisting arthritis, should avoid arthroscopy and go straight to TKA.