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In the overhead athlete, medial ulnar collateral ligament (MUCL) insufficiency can develop from repetitive valgus loads across the elbow during the throwing motion. This injury can be potentially career ending for the athlete. Treatment options include conservative care or potential surgical intervention with ligament reconstruction. Given the prolonged recovery period after surgical intervention, other avenues for successful treatment of MUCL insufficiency have been explored, including potential injections into the ligament such as platelet-rich plasma (PRP) and autologous stem cells. Recently, PRP has drawn interest as a tool for biologic augmentation of tendon and ligamentous healing as it is an autologous concentration of platelets and growth factors including vascular endothelial growth factor, insulin-like growth factor-1, fibroblast growth factor-2, platelet-derived growth factor, and transforming growth factor-s. Despite some evidence that supports the use of PRP injections for partial MUCL tears, there is no current consensus regarding its use. Research into the use of stem cell therapy remains primitive and while initial animal studies appear promising, their true clinical utility is unclear. Although the current literature is limited regarding the true efficacy of these treatment options, continued interest into the field of biologic augmentation still exists due to the potential for tissue regeneration. More specifically, biologic agents are especially appealing in the young overhead athlete with acute damage to an isolated part of the MUCL and in those athletes who are unwilling or unable to undergo the extended rehabilitation required after surgical reconstruction of the ligament.

This case study describes a Major League Baseball player who was diagnosed with an axillary artery thrombosis due to arterial compression from throwing. The purpose of this article is to create awareness as to the signs and symptoms associated with arterial positional compression and the rehabilitative implications to surgical intervention.

Vitamin D appears to play an important role in bone and cartilage metabolism since its receptors are widely found in human articular chondrocytes. Thus, effects of variation of vitamin D may directly impact cartilage and bone biology. The aims of this study are to compare (1) articular cartilage structure and composition and (2) trabecular and cortical bone microstructure in rats with normal versus insufficient vitamin D levels. Twenty-five mature, male Sprague-Dawley rats were allocated to two groups: (1) control arm (vitamin D replete—12 rats) and (2) an experimental arm (vitamin D deficient—13 rats). Vitamin D deficiency was induced using a vitamin D-deficient diet and UV light restriction. Rats were sacrificed after 4 weeks vitamin D deficiency was confirmed. The right knee was harvested for analysis of both the medial (MFC) and lateral femoral condyles (LFC). A region of interest was established on both condyles to correlate subchondral bone architecture and the overlying cartilage. Histological analysis was performed and graded using the modified Mankin score. Subchondral and cortical bony architecture was evaluated with micro-CT. After 4 weeks, the vitamin D-deficient group had statistically significant changes in cartilage structure in both the MFC and LFC [1.55 ± 0.6 vs. 4.23 ± 4.1 (p = 0.035) and 1.55 ± 0.6 vs. 3.53 ± 2.4 (p = 0.009), respectively]. Micro-CT analysis revealed no correlation between subchondral bone values and the overlying cartilage Mankin score (p = 0.460). No significant difference was evident between the subchondral bone of the control and study group. Low levels of vitamin D have a deleterious effect on the cartilage. Given the high prevalence of vitamin D deficiency in the general population, these findings raise important questions about the potential role of vitamin D in articular cartilage health.

The rotator cuff enthesis is not reestablished after a rotator cuff repair. Instead, a scar-mediated healing response occurs at the tendon-bone interface, which is notably weaker than the native enthesis and thus more prone to failure. Biological augmentation through growth factors, AASs, biomimetic scaffolds, or siRNA therapy has the potential to enhance the healing response. The ultimate key, however, is in determining which of these enables a more regenerative healing response of the native tissue rather than enhanced production of scar tissue. In addition, the optimal combination of factors, dosing, and delivery methods remains to be clearly elucidated. Biological augmentation and tissue engineering for tendon healing remains promising, but much work still needs to be done.

Ulnar nerve injuries are not uncommon among throwing athletes. The anatomy of the ulnar nerve and the course in which it travels through the upper extremity make it susceptible to injury, especially when the elbow is loaded in the extremes that come with throwing sports such as baseball pitching. In addition to occurring in isolation, ulnar nerve symptoms may present in patients with ulnar collateral ligament (UCL) insufficiency. Postoperative ulnar nerve dysfunction is the most commonly cited complication after reconstructive surgery. This can be attributed to the fact that the ulnar nerve is in close proximity to the native ulnar collateral ligament and is at risk for injury during surgery. To identify and protect the nerve, Jobe in his original description of the procedure, dissected out the nerve from the cubital tunnel and then transposed the nerve anteriorly in a submuscular fashion after the reconstruction was performed. However, the dissection and transposition itself may also present a risk for postoperative ulnar neuropathy. In light of this, Jobe’s original surgical technique which has undergone several modifications in the surgical approach to the UCL and handling of the ulnar nerve, which has improved the postsurgical complication rate.

In the overhead athlete, medial ulnar collateral ligament (MUCL) insufficiency can develop from the repetitive valgus loads across the elbow during the throwing motion. This injury can be potentially career ending for the athlete. Treatment options include conservative care or potential surgical intervention with ligament reconstruction. Given the prolonged recovery period after surgical intervention, other avenues for successful treatment of MUCL insufficiency have been explored including potential injections into the ligament including platelet-rich plasma (PRP). Recently, PRP has drawn interest as a tool for biologic augmentation of tendon and ligamentous healing as it is an autologous concentration of platelets and growth factors including vascular endothelial growth factor (VEGF), insulin-like growth factor-1 (IGF-1), fibroblast growth factor-2 (FGF-2), platelet-derived growth factor (PDGF), and transforming growth factor-s (TGF-s). Recent clinical work has shown that PRP injections into the MUCL may play a role in the management for the young overhead athlete that has acute damage to an isolated part of the ligament, and in those athletes that are unwilling or unable to undergo the extended rehabilitation required after surgical reconstruction of the ligament.

Background: Few studies have considered hormonal influences, particularly vitamin D, on healing. Hypothesis: Vitamin D deficiency would have a negative effect on the structure of the healing tendon-bone interface in a rat model and would result in decreased tendon attachment strength. Study Design: Controlled laboratory study. Methods: Vitamin D deficiency was induced in 28 male Sprague-Dawley rats using a specialized vitamin D–deficient diet and ultraviolet light restriction. Serum levels of vitamin D were measured after 6 weeks. These vitamin D–deficient animals (experimental group) plus 32 rats with normal vitamin D levels (controls) underwent unilateral detachment of the right supraspinatus tendon from the greater tuberosity of the humerus, followed by immediate repair using bone tunnel suture fixation. The animals were sacrificed at 2- and 4-week intervals after surgery for biomechanical analysis. A paired t test was used to compare serum vitamin D levels at day 0 and at 6 weeks. A nonparametric Mann-Whitney U test was used to compare load-to-failure and stiffness values between the experimental group and controls. Bone density and new bone formation at the tendon insertion site on the greater tuberosity were assessed with micro–computed tomography (CT). The organization of collagen tissue, new bone formation, vascularity at the tendon-bone interface, fibrocartilage at the tendon-bone interface, and collagen fiber continuity between the tendon and bone tissue were evaluated with safranin O and picrosirius red staining. Results: Blood draws confirmed vitamin D deficiency at 6 weeks compared with time zero/baseline for rats in the experimental group (10.9 ng/mL vs 6.5 ng/mL, respectively; P < .001). Biomechanical testing demonstrated a significant decrease in load to failure in the experimental group compared with controls at 2 weeks (5.8 ± 2.0 N vs 10.5 ± 4.4 N, respectively; P < .006). There was no difference in stiffness at 2 weeks between the control and experimental groups. At 4 weeks, there was no significant difference in load to failure or stiffness between the control and experimental groups. Histological analysis showed less bone formation and less collagen fiber organization in the vitamin D–deficient specimens at 4 weeks as compared with controls. Micro-CT analysis showed no significant difference between groups for total mineral density and bone volume fraction of cortical, whole, or trabecular bone at 4 weeks. Conclusion: The biomechanical and histological data from this study suggest that low vitamin D levels may negatively affect early healing at the rotator cuff repair site. Clinical Relevance: It is estimated that 1 billion people worldwide are vitamin D deficient. In the deficient state, acutely injured rotator cuffs may have a reduced ability for tendon healing. Further studies are needed to determine the exact mechanism by which vitamin D affects tendon healing and whether vitamin D supplementation can improve rotator cuff tendon healing and reduce the incidence of retears.

Vitamin D acts to maintain calcium and phosphate homeostasis within the body. It is now estimated that 1 billion people worldwide are vitamin D deficient. This problem is particularly important to athletes of all ages, as vitamin D plays a significant role in bone health, immune function, and physical performance. In the deficient state, the athlete may be at an increased risk for potential problems such as stress fractures, respiratory infections, and muscle injuries. The purpose of this article is to examine vitamin D deficiency and review its relationship to the athlete.