Bone health and the masters runner.

Masters runners are often defined as those ages 35 years and older who train and compete in running events. These runners represent a growing population of the overall running community and experience running-related injuries including bone stress injuries (BSIs). Similar to younger runners, health considerations in masters runners include the goal to optimize bone health with focus on mitigating age-associated loss of bone strength and preventing BSIs through a combination of ensuring appropriate physical activity, optimizing nutrition, and correcting faulty biomechanics. Importantly, BSIs in masters runners may include characteristics of both overuse injury from insufficient recovery and failure of bone weakened by age-related loss of bone (insufficiency fractures). This narrative review covers the limited available research on strategies to optimize bone health in masters runners. Applying knowledge on masters athletes and extrapolating from other populations, we propose strategies on treatment and prevention of BSIs. Finally, the review highlights gaps in knowledge that require further age-specific discoveries to advance treatment and prevention.

Reverse Anterior Cruciate Ligament Reconstruction Fixation: A Biomechanical Comparison Study of Tibial Cross-Pin and Femoral Interference Screw Fixation.

PURPOSE: To evaluate the biomechanical performance of tibial cross-pin (TCP) fixation relative to femoral cross-pin (FCP), femoral interference screw (FIS), and tibial interference screw (TIS) fixation. METHODS: We randomized 40 porcine specimens (20 tibias and 20 femurs) to TIS fixation (group 1, n = 10), FIS fixation (group 2, n = 10), TCP fixation (group 3, n = 10), or FCP fixation (group 4, n = 10) and performed biomechanical testing to compare ultimate load, stiffness, yield load, cyclic displacement, and load at 5-mm displacement. We performed cross-pin fixation of the looped end and interference screw fixation of the free ends of 9-mm-diameter bovine extensor digitorum communis tendon grafts. Graft fixation constructs were cyclically loaded and then loaded to failure in line with the tunnels. RESULTS: Regarding yield load, FIS was superior to TIS (704 ± 125 N vs 504 ± 118 N, P = .002), TCP was superior to TIS (1,449 ± 265 N vs 504 ± 118 N, P < .001), and TCP was superior to FCP (1,449 ± 265 N vs 792 ± 397 N, P < .001). Cyclic displacement for FCP was superior to TCP. Cyclic displacement for TIS versus FIS showed no statistically significant difference (2.5 ± 1.0 mm vs 2.2 ± 0.6 mm, P = .298). Interference screw fixation consistently failed by graft slippage, whereas TCP fixation failed by tibial bone failure. FCP fixation failed by either femoral bone failure or failure elsewhere in the testing apparatus. CONCLUSIONS: Regarding yield load, TCP fixation performed biomechanically superior to the clinically proven FCP at time zero. Because TIS fixation shows the lowest yield strength, it represents the weak link, and combined TCP-FIS fixation theoretically would be biomechanically superior relative to combined FCP-TIS fixation with regard to yield load. Cyclic displacement showed a small difference in favor of FCP over TCP fixation and no difference between TIS and FIS. CLINICAL RELEVANCE: Time-zero biomechanics of TCP fixation paired with FIS fixation show that this method of fixation can be considered a potential alternative to current practice and may pose clinical benefits in different clinical scenarios of anterior cruciate ligament reconstruction.