Pressures Exerted on the Hook of the Hamate in Collegiate Baseball Players: A Comparison of Grips, With Emphasis on Fracture Prevention.

BACKGROUND: Variations in batting technique may put baseball players at increased risk of hook of the hamate fractures. A better comprehension of the mechanism of such fractures is needed. PURPOSE/HYPOTHESIS: The purpose of the study was to compare 2 different grip types to quantify the pressures exerted on the hook of the hamate during batting. It was hypothesized that when compared with the conventional batting style, players holding the knob of the bat in the palm of the hand (termed the "palmar hamate grip") would have higher pressures exerted on the hook of the hamate. STUDY DESIGN: Controlled laboratory study. METHODS: Athletes were recruited for participation on a volunteer basis from the rosters of 2 National Collegiate Athletic Association Division I baseball teams and were divided into 2 groups based on their usual grip type. A force sensor system was applied to the nondominant hand of each participating player, with the central portion of the sensing mechanism placed on the batting glove directly over the hook of the hamate. All players used the same batting glove, which transmitted data from the sensor to a laptop computer. Measurements were collected on consecutive hits at a standardized distance using a ball machine at 70 mph. RESULTS: Nine collegiate baseball players underwent testing (5 players exclusively used the conventional grip, 3 players exclusively used the palmar hamate grip, and 1 player naturally alternated between the 2 grip types). The palmar hamate grip demonstrated a 366% increase in pressure exerted on the sensor overlying the hook of the hamate when compared with the conventional batting grip (536.42 kPa [95% confidence interval, 419.39-653.44 kPa] vs 115.84 kPa [95% confidence interval, 96.97-135.10 kPa]). The player who used both grips demonstrated significantly higher maximum pressure when using the palmar hamate versus conventional grip (482.90 vs 142.40 kPa; t = 6.95; P < .0001). CONCLUSION: Use of the palmar hamate grip may increase the risk of hook of the hamate fracture in National Collegiate Athletic Association Division I baseball players. CLINICAL RELEVANCE: Educating players on the risks associated with the palmar hamate grip may prevent injury and minimize time out of competition.

Suture Tape Augmentation for Scapholunate Ligament Repair: A Biomechanical Study.

PURPOSE: Scapholunate (SL) ligament tears in the acute setting can be treated by primary repair through various techniques. The purpose of this study was to compare repair of the SL ligament with suture anchors alone versus repair of the SL ligament augmented with suture tape. METHODS: Twelve fresh-frozen cadavers (6 matched pairs) underwent a dorsal approach to the wrist and the SL ligament was sharply dissected off of its scaphoid attachment. Six cadavers underwent direct repair of the SL ligament using 2 suture anchors. The other 6 underwent repair of the SL ligament, which was then augmented with suture tape. All specimens then underwent load to failure testing using tensile distraction forces applied by a universal testing system. Maximum load to failure and mode of failure were recorded. RESULTS: Maximum load to failure (135 N; SD, 44.94 N) for specimens that were repaired and augmented with the internal brace was higher than that for specimens in the repair-only group (68 N; SD, 14.69 N). CONCLUSIONS: Biomechanical testing demonstrated a higher maximum load to failure in SL ligament repairs augmented with suture tape compared with a repair-only technique in this cadaveric model. CLINICAL RELEVANCE: Acute SL ligament injuries may benefit from suture tape augmentation by increasing the stability of the primary repair. This may prove to be beneficial in higher-demand patients.

Cardiac Arrest and Death Attributable to the "Diving Response" Triggered During Incision and Debridement of an Abscess of the Forehead.

The authors discuss about a patient who, while undergoing a routine procedure to drain a subcutaneous abscess within his forehead, suffered cardiac arrest that we conclude was caused by an activation of the diving response. This reflex affects homeostatic function which alters respiration and preferentially distributes oxygen stores to the heart and brain. Under some conditions, however, this reflex can also trigger cardiovascular collapse and death. The diving reflex is can begin with triggering receptors that are sensitive to cold water, submersion, or pressure within the nasal cavity and other areas supplied by the trigeminal nerve. Studies have shown that this afferent response primarily involves branches of the infraorbital nerve and the anterior ethmoidal nerve. However, other more superior nerves such as those exclusive to the forehead region may also be involved. This study demonstrates for the first time the risks and dangers involved in surgical procedures or manipulation of the trigeminal innervated areas of the human face and in particular the forehead.

Innervation of the Elbow Joint: A Cadaveric Study.

PURPOSE: To describe elbow innervation patterns in 15 cadaveric extremities. METHODS: Fifteen fresh-frozen cadaveric upper extremities were dissected under loupe magnification. The median, radial, musculocutaneous, and ulnar nerves were dissected at the elbow joint and explored both proximally and distally to find capsular branches and identifiable anatomical patterns. RESULTS: In 11 of specimens, the ulnar nerve innervated the articular surface of the elbow joint with an average 1.5 branches. The radial nerve gave off a branch to the posterolateral capsule in 10 cases of the specimens, originating 11 ± 3 cm above the lateral epicondyle. After piercing the lateral intermuscular septum, this radial nerve branch innervated the anterolateral capsule in 12 cases (80%). The median nerve sent branches to the joint in 1 specimen. The musculocutaneous nerve innervated the anterior capsule with 1 or 2 branches in 10 of 13 specimens. CONCLUSIONS: The majority of the innervation of the anterior capsule comes from the radial and musculocutaneous nerves with minimal contribution from the median nerve. The ulnar and radial nerves innervate the posteromedial and posterolateral capsule, respectively. CLINICAL RELEVANCE: Accurate understanding of peripheral nerve anatomy is essential for future elbow denervation studies.

Open shoulder stabilization procedure using bone block technique for treatment of chronic glenohumeral instability associated with bony glenoid deficiency.

We examined the early results of using an open bone block technique to stabilize the glenohumeral joint with chronic instability related to bony deficiency of the glenoid. Fifteen patients with anteroinferior glenoid bone loss on preoperative computed tomography underwent diagnostic shoulder arthroscopy (for evaluation of glenoid bony deficiency) and then open bone block augmentation of the anteroinferior glenoid rim. Clinical follow-up of 10 patients at a mean of 25 months showed a mean postoperative Constant score of 94 (range, 32-100), a mean University of California Los Angeles score of 32 (range, 9-35), and a mean American Shoulder and Elbow Surgeons score of 83 (range, 47-100). Mean postoperative forward flexion was 172 degrees, mean postoperative external rotation with the arm at the side was 60 degrees , mean postoperative external rotation with the arm abducted 90 degrees was 91 degrees, and postoperative internal rotation ranged from the level of the anterosuperior iliac spine (minimal external rotation) to the T6 spinal level. Bone block stabilization is an effective treatment in patients with chronic shoulder instability--a difficult population.

Medical malpractice and the sports medicine clinician.

More individuals are participating in athletics today than ever before. Physicians treating athletes confront unique diagnostic and treatment challenges and an increased risk of legal liability. The key areas regarding liability are preparticipation examinations, determination of eligibility, evaluation of significant on-field injuries, and information disclosure. The issues surrounding preparticipation physicals and determination of eligibility are closely linked. Physicians must be prepared to seek guidance from specialists, particularly when there are cardiac, spinal, or neurologic issues. Appropriate on-field evaluation of potential concussions, spinal injuries, and heat stroke are key areas of concern for the physician. Privacy issues have become more complex in the age of federal regulation. Physicians and all athletic staff should be aware of privacy laws and ensure proper consent documentation is obtained from all athletes or their parents. All athletic programs should develop a plan that details roles and procedures to be followed in a medical emergency. Sports caregivers must take affirmative steps that better protect their patients from harm and physicians from legal liability.

Medial clavicular epiphyseal fracture with ipsilateral acromioclavicular dislocation: a case report of panclavicular fracture dislocation.

The authors report a case of a complete posterior dislocation of the acromioclavicular (AC) joint with an ipsilateral medial epiphyseal clavicular fracture in a 20-year-old male. Open reduction was indicated because a maintained closed reduction of the AC joint was unsuccessful, and the described treatment maintained a successful reduction.

MRI description of knee medial collateral ligament abnormalities in the absence of trauma: edema related to osteoarthritis and medial meniscal tears.

A retrospective case series regarding the knees of 12 adult patients with MRI abnormalities of the medial collateral ligament (MCL), but without clinical history of trauma to the MCL, were collected and compared with six knee MR images from patients with clinical traumatic injuries to their MCLs. The MR images were studied for the extent of edema of the MCL, as well as other associated findings. Edema of the MCL on MRI could be found in three distinct categories of patients: (a) those with trauma to the MCL, which was an expected finding; (b) those without trauma but with medial compartment osteoarthritis; and (c) those without trauma but with degenerative medial meniscal tears. The clinical significance, if any, of the edema found in MCLs without trauma remains unclear. Atraumatic MCL edema may serve as a marker for medial knee compartment osteoarthritis or for a degenerative medial meniscal tear and should not be confused with traumatically induced MCL injuries, although this distinction can often be difficult to make based on MRI findings alone.

The incidence of rotator cuff disease in smoking and non-smoking patients: a cadaveric study.

The etiology of rotator cuff disease is multifactorial. One theory behind the high incidence of rotator cuff tears in the shoulder is that the supraspinatus/infraspinatus tendon contains a zone of relative avascularity in the area proximal to its insertion at the greater tuberosity. Tobacco smoking is known to contribute to microvascular disease, and it can be hypothesized that smoking tobacco further compromises the vascular supply to the supraspinatus/infraspinatus tendon, thus increasing the incidence of tendinous pathology in the rotator cuff. This article evaluates the rotator cuffs of 72 shoulders in 36 cadavers and compares the incidence of macroscopic and microscopic disease within the rotator cuff tendon. Microscopic evaluation of the accompanying lung tissue from the respective cadaver also was performed. As a result, we were able to determine the presence or absence of a smoking history or emphysema from each cadaver as it related to rotator cuff disease in the shoulder. Of the 36 shoulders that exhibited macroscopic rotator cuff tears, 23 were from cadavers with a history of smoking compared to only 13 from cadavers with no history of smoking. Furthermore, the presence of advanced microscopic rotator cuff pathology (Grade 3 or 4 fibrous degeneration) was more than twice as likely in the cadavers with a history of smoking (22/32) compared to only 10 of 32 shoulders from cadavers with no history of smoking. While none of this data was statistically significant due to the insufficient number of subject cadavers, strong trends were noted in these findings.

Head-first versus feet-first sliding: a comparison of speed from base to base.

BACKGROUND: Two basic baseball sliding techniques, feet-first and head-first, are taught at all levels of play. Because of the risk for injury to the upper extremities and the cervical spine during head-first sliding, it is potentially more dangerous than feet-first sliding. There is an assumption among coaches that head-first sliding is more aggressive and faster, but there has been no scientific study to prove this claim. PURPOSE: The purpose of this study was to determine which technique provides a faster slide into the base. STUDY DESIGN: Controlled field study. METHODS: A total of 60 players ranging from Little League to college level was analyzed. Each athlete was evaluated three times from a standing start at first base to either a head-first or feet-first touch of second base. Each athlete was also timed in a 40-yard sprint and his or her preferred sliding technique was recorded. RESULTS: We found no statistically significant difference in speed between head-first and feet-first sliding at all levels of play in this study.