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.

Comparison of Ultrasonography to MRI in the Diagnosis of Lower Extremity Bone Stress Injuries: A Prospective Cohort Study.

OBJECTIVE: To determine the sensitivity and specificity of ultrasound imaging (USI) compared to the reference-standard of MRI in the diagnosis of bone stress injury (BSI). METHODS: A prospective blinded cohort study was conducted. Thirty seven patients who presented to an academic sports medicine clinic from 2016 to 2020 with suspected lower-extremity BSI on clinical exam underwent both magnetic resonance imaging (MRI) and USI. Participant characteristics were collected including age, gender and sport. Exclusion criteria included contraindication for dedicated MRI, traumatic fracture, or severe tendon or ligamentous injury. The primary outcome measure was BSI diagnosis by USI. An 8-point assessment system was utilized on USI for diagnosis of BSI, and the Fredericson and Nattiv22 criteria were applied to classify MRI findings. RESULTS: Thirty seven participants who met study criteria were consented to participate. All participants completed baseline measures. Using MRI, there were 30 (81%) athletes with a positive and seven participants with a negative BSI diagnosis. The most common BSIs in the study were in the metatarsal (54%) and tibia (32%). Compared to MRI, USI demonstrated 0.80 sensitivity (95% confidence interval [CI], 0.61-0.92) and 0.71 specificity (95% CI, 0.29-0.96) in detecting BSI, with a positive predictive value of 0.92 (95% CI, 0.75-0.99) and negative predictive value of 0.45 (95% CI, 0.17-0.77). CONCLUSIONS: USI is a potentially useful point-of-care tool for practicing sports medicine providers to combine with their clinical evaluation in the diagnosis of BSIs. Further research is ongoing to determine the role of USI in follow-up care and return-to-play protocols.

All-Epiphyseal Physeal-Sparing Anterior Cruciate Ligament Reconstructive Surgery: A Study of 3-Dimensional Modeling to Characterize a Safe and Reproducible Surgical Approach.

PURPOSE: The purpose of this study was to use 3-dimensional magnetic resonance imaging modeling of the skeletally immature knee to help characterize safe and reproducible tunnel positions, diameters, lengths, trajectories, and distances from anatomic landmarks and the physeal and articular cartilage for physeal-sparing anterior cruciate ligament (ACL) reconstructive surgery. METHODS: Magnetic resonance imaging from 19 skeletally immature knees with normal anatomy were gathered. The 3-dimensional models were created, and the relevant anatomic structures were identified. Cylinders simulating tunnel length, diameter and trajectory were superimposed onto the models, and descriptive measurements were performed. RESULTS: A safe position for the creation of an 8 mm diameter femoral tunnel was described in the lateral femoral condyle. The femoral tunnel length averaged 25.5 ± 2.6 mm. The bony entry point was located 3.8 ± 2.4 mm proximally and 12.7 ± 2.2 mm posteriorly to the lateral epicondyle. The shortest distance from the tunnel edge to the physis and femoral articular cartilage was 2.8 ± 0.7 mm and 3.7 ± 0.9 mm, respectively. The safe position for an 8 mm diameter tibial tunnel was also identified and described in the proximal tibia. The epiphyseal tibial tunnel length from the ACL footprint to the physis averaged 15.5 ± 1.6 mm. The proximal tibial epiphysis was found to accommodate a tibial crosspin measuring 63.5 ± 5.9 mm in length and 8.2 ± 1.5 mm in diameter without disrupting the physis or articular cartilage. CONCLUSIONS: Three-dimensional modeling created from magnetic resonance imaging can help define important anatomic relationships for physeal-sparing ACL reconstructive surgery in skeletally immature knees and may assist in reducing the risk of injury to local anatomic structures. CLINICAL RELEVANCE: Knowledge of the anatomic relationships in skeletally immature knees serves as a valuable reference for surgeons performing physeal-sparing ACL reconstruction surgery.

Vitamin D for Improved Bone Health and Prevention of Stress Fractures: A Review of the Literature.

Vitamin D is a vital nutrient and hormone needed for many essential functions in overall health. There is growing literature examining the role of vitamin D not only in the general population but also in athletes. The most predominantly studied area of vitamin D pertains to bone health. Recently, there has been increased investigation into the relationship of vitamin D and stress fractures, including genetic polymorphisms, levels of 25-hydroxyvitamin D, and bioavailable vitamin D. This review will address the most recent developments of vitamin D research and its important role in bone health in athletes.

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.