New NCAA Bat Standard, BBCOR, is Associated with an Increased Incidence of Hamate Fractures.

Our institution saw four hamate fractures in the 2011 baseball season, the first season following implementation of new batting standards in collegiate baseball. The purpose of this paper was to identify whether the incidence of hamate fractures increased with the introduction of the new batting standard. Surveys sent to Division 1 collegiate baseball athletic trainers reported the number, mechanism, treatment and return to play of hamate fractures from 2008-2010 (old batting standards) and for the 2011 season. This study shows that there was more than a 200% increased risk of hamate fracture with implementation of the 2011 collegiate baseball batting standards. The most common injury mechanism was batting with the down hand (79%). We suggest that a national injury database be considered for collegiate athletics so that injury rates, risk factors and results of interventions could be studied to improve the health of our nations' athletes. (Journal of Surgical Orthopaedic Advances 28(4):285-289, 2019).

Strength of bone tunnel versus suture anchor and push-lock construct in Broström repair.

BACKGROUND: Operative treatment of mechanical ankle instability is indicated for patients who have had multiple sprains and have continued episodes of instability despite bracing and rehabilitation. Anatomic reconstruction has been shown to have improved outcomes and return to sport as compared with nonanatomic reconstruction. HYPOTHESIS: The use of 2 suture anchors and a push-lock anchor is equal to 2 bone tunnels in strength to failure for anatomic Broström repair. STUDY DESIGN: Controlled laboratory study. METHODS: In 7 matched pairs of human cadaver ankles, the calcaneofibular ligament (CFL) and anterior talofibular ligament (ATFL) were incised from their origin on the fibula. A No. 2 Fiberwire suture was placed into the CFL and a separate suture into the ATFL in a running Krackow fashion with a total of 4 locking loops. In 1 ankle of the matched pair, the ligaments were repaired to their anatomic insertion with bone tunnels. In the other, 2 suture anchors were used to reattach the ligaments to their anatomic origins, and a push-lock was used proximally to reinforce these suture anchors. The ligaments were cyclically loaded 20 times and then tested to failure. Torque to failure, degrees to failure, and stiffness were measured. The authors performed a matched pair analysis. An a priori power analysis of 0.8 demonstrated 6 pairs were needed to show a difference of 30% with a 15% standard error at a significance level of .05. RESULTS: There was no difference in the degrees to failure, torque to failure, and stiffness. A post hoc power analysis of torque to failure showed a power of .89 with 7 samples. Power for initial stiffness was .97 with 7 samples. Eleven of 14 specimens failed at either the suture anchor or the bone tunnel. CONCLUSION: There is no statistical difference in strength or stiffness for a suture anchor and push-lock construct as compared with a bone tunnel construct for an anatomic repair of the lateral ligaments of the ankle. CLINICAL RELEVANCE: The use of suture anchors in lateral ligament stabilization allows for a smaller incision, less surgical dissection, and improved surgical efficiency. It is up to the discretion of the performing surgeon based on preference, ease of use, operative time, and cost profile to choose either of these constructs for anatomic repair of the lateral ligaments of the ankle. The suture repair at the ligament was significantly strong enough such that the majority of ankles failed at the bone interface.

The anatomy of the supraclavicular nerve during surgical approach to the clavicular shaft.

BACKGROUND: Surgery for clavicular shaft fractures is becoming more common but incisional and chest wall numbness reportedly occurs in 10% to 29% of patients. This may be the result of iatrogenic injury to the supraclavicular nerve branches. QUESTIONS/PURPOSES: We determined if there was a predictable branching pattern of the supraclavicular nerve at the anterior clavicular border and determined the distances to these nerves from clavicular landmarks. METHODS: We performed an anatomic dissection along the anterior border of the long axis of the clavicle in 37 cadavers. The branches of the supraclavicular nerve were identified at the anterosuperior clavicular border and the distances from these nerves to palpable bony landmarks were measured. RESULTS: Ninety-seven percent of specimens had a medial and a lateral branch of the supraclavicular nerve. Nearly half (49%) possessed an additional intermediate branch. No branch was found within 2.7 cm of the sternoclavicular joint or within 1.9 cm of the acromioclavicular joint. Between these two positions, there was wide variability in nerve branch location. CONCLUSIONS: There were two or three branches of the supraclavicular nerve crossing the clavicle 97% of the time and a wide variability of the location of these branches outside the safe zones. CLINICAL RELEVANCE: There are safe zones within 2.7 cm of the sternoclavicular joint and 1.9 cm of the acromioclavicular joint. Between these safe zones, the location of the nerve branches is variable and the surgeon must use meticulous dissection if he or she wishes to prevent transection.

Interleukin-1beta inhibits expression of p21(WAF1/CIP1) and p27(KIP1) and enhances proliferation in response to platelet-derived growth factor-BB in smooth muscle cells.

OBJECTIVE: Intimal growth depends on smooth muscle cell (SMC) migration and proliferation and is regulated by thrombotic and inflammatory responses to vascular injury. Platelet-derived growth factor (PDGF)-BB and interleukin (IL)-1beta have been shown to contribute to intimal hyperplasia and lesion progression in atherosclerosis. Mitogenic effects of IL-1 on SMCs have been reported and have been attributed to the expression of PDGF-A chain. In some, but not all, studies, IL-1beta was found to cooperate with growth factors, including PDGF, in stimulating proliferation. The molecular basis for such cooperative effects is unknown and is the subject of the present study. METHODS AND RESULTS: We demonstrate that in baboon aortic SMCs, IL-1beta enhances the proliferation induced by PDGF-BB independently of PDGF-A signaling. IL-1beta increases the phosphorylation of retinoblastoma protein, a pivotal step in the G(1)-to-S transition in the cell cycle. Analysis of expression levels of cyclins and cyclin-dependent kinase (CDK) inhibitors suggests that IL-1beta stimulates CDKs by downregulating p21 and p27. Consistent with this hypothesis is the finding that CDK2 activity, induced by PDGF-BB, is enhanced 2.3+/-0.2-fold in the presence of IL-1beta. CONCLUSIONS: Our data suggest that IL-1beta may promote SMC proliferation after vascular injury and in atherogenesis by suppression of PDGF-BB-induced p21 and p27.