Injury to the ulnar collateral ligament (UCL) of the thumb metacarpophalangeal (MCP) joint is a common entity encountered by the sports physician and orthopedic surgeon. The term "gamekeeper's thumb," which is sometimes used incorrectly to mean any injury to this ligament, refers to a chronic injury to the UCL in which it becomes attenuated through repetitive stress. In contrast, the term "skier's thumb" refers to an acute ligament injury as seen in skiers who fall on an abducted thumb or athletes who sustain a valgus force on an abducted thumb. If the patient allows a clinical examination, valgus stress testing can diagnose a complete UCL rupture when there is no solid endpoint with the thumb held in 30 degrees of MCP flexion and with the thumb held in extension. In cases with complete UCL tears, operative treatment has been shown to produce excellent results and is recommended. If there is a firm endpoint to valgus stress testing, a partial UCL tear is diagnosed and nonoperative treatment usually favored.

Neuromuscular junction destabilization following nerve injury contributes to irreversible functional impairment. Myogenic Regulatory Factors (MRF's) including myoblast determination factor (MyoD), MRF-4, Myogenin, and myogenic factors-5 (myf-5), and Growthassociated protein 43 KDa (GAP43) regulate gene expression of nicotinic acetylcholine receptor (nAChR) subunits (alpha, beta, delta, gamma, and epsilon). We hypothesized that nerve injury induces altered gene expression of MRF's, nAChRs, and GAP-43 in the skeletal muscle which destabilize neuromuscular junctions. The tibial nerve was transected in 42 juvenile male SpragueDawley rats. Denervated and contralateral control gastrocnemius m. mRNA for nAChR subunits, MRF's, and GAP-43 were determined by real time reverse transcription polymerase chain reaction (real time RT-PCR). After transection, muscle mass decreased for 1 year with a nadir of 75% at 3 months. Alpha, gamma, and epsilon subunit genes increased by 3 and peaked at 7 days before returning to control levels (P < 0.05). Beta subunits and GAP-43 tended to increase. Delta subunits peaked at 3 days returning to control levels by 30 days. By one month, most of the nAChR subunits had returned to control levels. Alpha, beta, gamma, and delta subunit expression remained significantly lower than control up to 1 year later (P < 0.05). MRF4, Myogenin, and MyoD expression paralleled that of alpha, gamma, and epsilon nAChR subunits (P < 0.05). Gene expression of nAChR alpha, gamma, delta and epsilon subunits was biphasic in the first month after nerve injury, similar to that of MRF's. nAChR subunits and MRF's may play a critical role in neuromuscular junction stability. ß

Intramuscular gastrocnemius BoNT-A injections were associated with a significant reduction in force-generating potential, such that the muscle was incapable of actively producing enough force to rupture the repaired Achilles tendon in this rat model of tendon repair.

Use of the mini c-arm to assist in the closed reduction of pediatric forearm and wrist fractures in the emergency department can improve the quality of the reduction, decrease the radiation exposure to the patient, and decrease the need for repeat fracture reduction or additional procedures. Mini-c-arm imaging can also decrease the average orthopaedic consultation time for fracture reduction.