Journal of Musculoskeletal Research

An estimated 3 million youth participate in youth baseball. The purpose of this review is to highlight musculoskeletal development and specific throwing-related injuries in youth baseball players, as well as the current knowledge of pitching biomechanics, which are closely intertwined with the both arm development and injuries. Methods: A systematic literature review was conducted to highlight musculoskeletal development, throwing-related injuries and pitching mechanics. Results: Youth athletes are actively going through skeletal maturation which includes the formation of new bone at the epiphyseal plate, increasing muscle mass and/or strength, and morphological changes in tendons and ligaments. These processes setup youth pitchers to sustain throwing injuries at their shoulder and elbow in ways that differ from their adult counterparts. Faulty pitching biomechanics may also cause throwing injuries. Deviation from proper mechanics at any point can cause injuries in the shoulder and elbow. Conclusion: Many musculoskeletal changes occur during the development of a youth baseball player. Some of these changes are beneficial for improving throwing performance, but also predispose the athlete to injury. Improper biomechanics may be related to the throwing-related injuries that are seen in youth baseball players.

Objective: To evaluate whether 60${}^{\circ }$ and 90${}^{\circ }$ V-shaped osteotomies in sheep femurs have statistically significant differences when submitted to compressive strength tests. Material and Methods: A total of 30 left femurs of recently slaughtered sheep were removed, the proximal segment was discarded, and the bones were randomly divided into two groups of 15 specimens each. The bones underwent distal osteotomy at the supracondylar region at a 90${}^{\circ }$ angle between cuts, in group 1, and at a 60${}^{\circ }$ angle in group 2. The osteotomy was V-shaped and the distal apex started in the lateral face of the femur; medial cortical bone remained intact. Compressive tests were conducted, and four points of the deformation curve were collected for the calculation of the deformation rate using an interpolation scheme. Deformation patterns were evaluated according to two groups: intercondylar fracture and medial cortical fracture. Results: Group 1 had a mean resistance to failure to compressive load of 232kgf (SD 59.551; 150-400), whereas in group 2, mean resistance to failure to compressive load was 157.13kgf (SD 67.4; 70-346); this difference was statistically significant ($p=0.000619$, Kruskal–Wallis). Conclusions: Osteotomy at a 90${}^{\circ }$ angle had a greater resistance to compression and resulted in less weakening of the distal area of the femur after osteotomy. There were no differences in the pattern of fracture generated by compression according to osteotomy angle.

Purpose: To characterize muscle recovery following total hip arthroplasty (THA) combining genetic adaptations in the affected leg with objective function and body composition assessment. Methods: Preoperatively and at six weeks postoperatively, objective function was assessed by: maximal voluntary contraction of the operated leg quadriceps (MVCOLQ) in Newtons (N), 30s chair sit-to-stand (ST), and six-minute walk test (6MWT), with lean mass of the operated leg estimated by dual energy X-ray absorptiometry (DEXA). Genetic adaptations were assessed from vastus lateralis (VL) biopsies by quantitative polymerase chain reaction (qPCR) analysis of markers of hypertrophy (FOS, calpain2 (CAPN2)), atrophy (20s proteasome alpha subunit 7 (PSMA7), cathepsin L2 (CTSL2), inflammation (Tumour necrosis factor alpha (TNF-$\alpha$), Interleukin-6 (IL-6)) and lipid metabolism (lipoprotein lipase, LPL and peroxisome proliferated activated receptor gamma (PPARAG). Results: 14 patients were recruited. At six weeks, no significant differences, relative to preoperative values, were noted in either objective function or leg lean mass. Markers for hypertrophy were increased (FOS $+$1463%, $p=0.016$), with atrophy (PSMA7 $-$44.8%, $p=0.016$; CTSL2 $-$42.5%, $p=0.050$), inflammation (TNF $-$29.6%, $p=0.023$) and lipid metabolism markers showing a decreasing trend (LPL $-$42.45%, $p=0.016$). Conclusion: The initial post-THA intramuscular environment appears supportive of anabolism. However, this is not reflected in objective function or lean mass measures at six weeks, suggesting longer duration may be required for physiological adaptation to occur.

Purpose: To investigate the effect of weekly single high dose vitamin D supplementation on serum 25-hydroxyvitamin D [25(OH)D], and non-specific musculoskeletal pain in female nurses. Methods: In this prospective study in Kashan/Iran, from April 1, 2014, through September 30, 2014, the 150 nurses with vitamin D deficiency received the weekly pearls of 50,000 units of vitamin D₃ for 10 weeks. The serum level of 25(OH)D was measured before and after supplement therapy. The subjects were also asked to complete the Extended Nordic Musculoskeletal Questionnaire. All analyses were conducted with SPSS version 16. Results: After 10 weeks of intervention there was $21.3\pm 9.8$ng/mL increase in 25(OH)D. The 82 nurses (54.7%) had 25(OH)D in normal range, while the 68 nurses (45.3%) were still vitamin D deficient. Weight could explain 15.4% increase in 25(OH)D. Before intervention 135 (90%), of nurses reported musculoskeletal pain in at least one region, after intervention this number decreased to 72.7%. There was a statistically significant improvement in musculoskeletal pain in neck, shoulders, upper back, lower back, hips/tights, knees, and ankles/feet after intervention. Conclusions: The weekly single high dose of vitamin D for 10 weeks could resolve vitamin D deficiency in about half of the patients. Patients with non-specific musculoskeletal pain might benefit from vitamin D supplementation.

Typical gait analyses commonly define the trunk as a single rigid segment, which overlooks its inter-segmental motion. The current study examined the validity and reliability of a multi-segmented trunk marker set and the quantification of trunk motion during gait. A total of 10 young subjects were tested on two different days using identical procedures which incorporated a 22-marker set to define 7 trunk segments. Validity was evaluated by comparing results to a previous protocol. Reliability was assessed with the range of motion (ROM), coefficient of multiple correlation (CMC) and intraclass correlation coefficient (ICC). The multi-segmented trunk marker set was able to reveal different inter-segmental movement patterns. During gait, ROM reliability was approximately 92%, and within-day CMC displayed moderate to strong reliabilities while between-day CMC data had moderately weak to moderately strong associations of the multi-segmented angle waveform trajectories. Reliability of the peak angles, assessed by ICC ranged from poor to almost perfect. The findings provide trends that suggest the incorporation of a multi-segmented trunk marker set could add a useful assessment to gait analysis.

Purpose: To determine the immediate effect of kinesiology taping in treating undisplaced rib fracture pain. Method: The study is a retrospective in which 10 Patients (5 females and 5 males) with 1 or 2 undisplaced middle rib fractured (5th, 6th, 7th) were included. The age group of the patients was 27–57 years. The diagnosis was made by the orthopedic surgeon and referred to Institute of Kinesiology Taping. Numeric pain rating scale readings were obtained and documented before and after the taping session. Results: A significant decrease in pain before and after the kinesiology taping was found both while deep breathing ($p<$0.001) and during coughing ($p>$0.001). The Mean$\pm$ S.D of NPRS reading in case of pre and post taping for deep breathing was 5.7$\pm$0.95 and 4.4$\pm$0.84, respectively and that for coughing was 7.2$\pm$0.63 and 4.7$\pm$1.16, respectively. Conclusion: Kinesiology taping has immediate effect in treating undisplaced middle rib fracture pain.