The Danger Zone for Noise Hazards Around the Black Hawk Helicopter.

BACKGROUND: During ground operations, rotary-wing aircraft engines and subsystems produce noise hazards that place airfield personnel at risk for hearing damage. The noise exposure levels outside the aircraft during various operating conditions, and the distances from aircraft at which they drop to safe levels, are not readily available. The current study measured noise levels at various positions around the UH-60 Black Hawk helicopter for three operating conditions typically used when the aircraft is on the ground. METHODS: Microphones were positioned systematically around the helicopter and A-weighted sound pressure levels (SPLs) were computed from the recordings. In addition, the 85-dBA SPL contour around the aircraft was mapped. The resulting A-weighted SPLs and contour mapping were used to determine the noise hazard area around the helicopter. RESULTS: Measurements reported here show noise levels of 105 dB or greater in all operating conditions. The fueling location at the left rear of the aircraft near the auxiliary power unit (APU) is the area of greatest risk for noise-induced hearing loss (NIHL). Additionally, sound field contours indicate noise hazard areas (>85 dBA SPL) can extend beyond 100 ft from the helicopter. CONCLUSIONS: This report details the areas of greatest risk for auditory injury around the UH-60 Black Hawk helicopter. Our findings suggest the area of hazardous noise levels around the aircraft can extend to neighboring aircraft, particularly on the side of the aircraft where the APU is located. Hearing protection should be worn whenever the aircraft is operating, even if working at a distance.Jones HG, Greene NT, Chen MR, Azcona CM, Archer BJ, Reeves ER. The danger zone for noise hazards around the Black Hawk helicopter. Aerosp Med Hum Perform. 2018; 89(6):547-551.

The effect of nonsteroidal anti-inflammatory drugs on tissue healing.

PURPOSE: Non-selective (NSAIDs) and selective (COX-2) nonsteroidal anti-inflammatory drugs are commonly used for their analgesic and anti-inflammatory effects. Their role after orthopaedic surgery has been infrequently described and remains controversial because of unclear effects on soft tissue and bone healing. This study critically reviews the available literature to describe the effects of NSAIDs and COX-2 inhibitors on soft tissue and bone healing. METHODS: A Medline search was performed using NSAIDs or COX-2 inhibitors and tissue healing. The combined search yielded 637 articles. Following exclusion, 44 articles were deemed relevant with 9 articles on soft tissue healing and 35 articles on bone healing. The available evidence is based primarily on animal data (39 studies), with considerable variation in study methods. RESULTS: In regard to soft tissue healing, there is insufficient evidence of a detrimental effect when using either NSAIDs or COX-2 inhibitors at standard doses for ≤2 weeks. For soft tissue to bone healing, a limited number of studies demonstrate impairment in healing. However, with respect to bone healing, indomethacin appears to have a clear detrimental effect, with less substantial evidence for other NSAIDs. CONCLUSIONS: Short-term, low-dose use of NSAIDs and COX-2 inhibitors does not appear to have a detrimental effect following soft tissue injury, but is inhibitory in cases involving bony healing. However, additional well-controlled human studies are necessary to draw more definitive conclusions regarding their role. Clinically, the prudent use of anti-inflammatory medications following sports medicine injuries and surgeries appears to be a reasonable option in clinical practice unless bone healing is required. LEVEL OF EVIDENCE: III.

Anatomic variability of 120 L5 spondylolytic defects.

Study Design Adult human osteologic specimens were assessed for spondylolytic defects and characterized. Objectives To characterize and determine the prevalence of spondylolytic defects in an osteological collection. Methods Lumbar vertebrae from the Hamann-Todd Osteological Collection at the Cleveland Museum of Natural History were examined. Digital images of specimens with L5 isthmic spondylolytic defects were analyzed, examining the distance of the pars defect in the sagittal plane in relation to the caudal aspect of the pedicle. Results There were 95 bilateral complete (BC), 16 unilateral incomplete (UI), 5 unilateral complete (UC), and 4 unilateral complete defects with an incomplete defect on the contralateral side. The mean distance of BC defects from the pedicle and inferior vertebral end plate was 4.03 mm and 4.88 mm, respectively. The mean distance of the defect from the inferior end plate on the left and right sides were 5.31 mm and 4.44 mm, respectively (p = 0.001, correlation coefficient = 0.56). The mean distance of UI and UC defects from the inferior end plate was 6.38 mm and 2.6 mm, respectively. Conclusion L5 spondylolytic defects were found in 3.87% of the sample. This large-scale description of isthmic spondylolytic defects reveals that significant variability exists in the location of the defect. The anatomic location of the pars defect likely plays a role in the development of L5 nerve root compression and radiculopathy in this clinical scenario. Classifying these defects might allow surgeons to better identify those patients who might benefit from fusion alone without posterior decompression.

Incidence and risk factors for injuries to the anterior cruciate ligament in National Collegiate Athletic Association football: data from the 2004-2005 through 2008-2009 National Collegiate Athletic Association Injury Surveillance System.

BACKGROUND: Injuries to the anterior cruciate ligament (ACL) are common in athletic populations, particularly in athletes participating in football, soccer, and skiing. PURPOSE: The purpose of this study was to analyze the National Collegiate Athletic Association (NCAA) Injury Surveillance System (ISS) men's football ACL injury database from the playing seasons of 2004-2005 through 2008-2009 to determine the incidence and epidemiology of complete injury to the ACL in NCAA football athletes. STUDY DESIGN: Descriptive epidemiology study. METHODS: The NCAA ISS men's football database was reviewed from the 2004-2005 through 2008-2009 seasons using the specific injury code, "Anterior cruciate ligament (ACL) complete tear." The injury rate was computed for competition and practice exposures. Ninety-five percent confidence intervals (CIs) for the incident rates were calculated using assumptions of a Poisson distribution. Pairwise, 2-sample tests of equality of proportions with a continuity correction were used to estimate the associations of risk factors such as event type, playing surface, season segment, and football subdivision. Descriptive data were also described. RESULTS: The ACL injury rate during games (8.06 per 10,000 athlete-exposures [AEs] 95% CI, 6.80-9.42) was significantly greater than the rate during practice (0.8 per 10,000 AEs 95% CI, 0.68-0.93). Players were 10.09 (95% CI, 8.08-12.59) times more likely to sustain an ACL injury in competition when compared with practices. When practice exposures were analyzed separately, the injury rate was significantly greater during scrimmages (3.99 per 10,000 AEs 95% CI, 2.29-5.94) compared with regular practices (0.83 per 10,000 AEs 95% CI, 0.69-0.97) and walk-throughs (0 per 10,000 AEs 95% CI, 0-0.14). There was an incidence rate of 1.73 ACL injuries per 10,000 AEs (95% CI, 1.47-2.0) on artificial playing surfaces compared with a rate of 1.24 per 10,000 AEs (95% CI, 1.05-1.45) on natural grass. The rate of ACL injury on artificial surfaces is 1.39 (95% CI, 1.11-1.73) times higher than the injury rate on grass surfaces. CONCLUSION: Between 2004 and 2009, NCAA football players experienced a greater number of ACL injuries in games compared with practices, in scrimmages compared with regular practices, and when playing on artificial turf surfaces. This latter finding will need to be confirmed by additional studies.

Arthroscopic releases for arthrofibrosis of the knee.

Intra-articular inflammation or fibrosis may lead to decreased soft-tissue and capsular compliance, which may result in pain or loss of motion within the knee. Etiology of intra-articular fibrosis may include isolated anterior interval scarring and posterior capsular contracture, as well as fibrosis that involves the suprapatellar pouch or arthrofibrosis that involves the entire synovial space. Initial nonsurgical management, including compression, elevation, and physical therapy, can decrease knee pain and inflammation and maintain range of motion. Surgical management is indicated in the patient who fails conservative treatment. Surgical options include arthroscopic releases of the anterior interval, posterior capsule, and peripatellar and suprapatellar regions. Recent advances in arthroscopic technique have led to improved outcomes in patients with intra-articular fibrosis of the knee.

Radiographic classification of the femoral intercondylar notch posterolateral rim.

PURPOSE: The purpose of this study was to determine whether posterolateral rim morphology can be delineated on plain radiographic images. METHODS: We obtained 20 femora from the Cleveland Museum of Natural History (10 each with distinct and indistinct posterolateral rims). Four blinded reviewers evaluated radiographic posterolateral rim morphology on lateral radiographs. The reviewers included a musculoskeletal radiologist, a fellowship-trained sports medicine surgeon, a pediatric orthopaedic surgeon, and a junior orthopaedic resident. Interobserver and intraobserver reliability was determined. RESULTS: Radiographically, posterolateral rim morphology was classified into 2 types. Type 1 rims have a defined transition from Blumensaat's line to the posterior femoral cortex. Type 2 rims have an indistinct transition. Interobserver reliability showed substantial agreement during the first (kappa = 0.65) and second (kappa = 0.70) sessions. Intraobserver reliability was nearly perfect, with kappa values ranging from 0.8 to 1.0. CONCLUSIONS: It has been shown anatomically that the posterolateral rim has variable morphology. We have shown that posterolateral rim morphology can be delineated on lateral plain film images. Radiographic type 1 rims correlate with distinct posterolateral rim morphology. Radiographic type 2 rims correlate with indistinct posterolateral rim morphology. CLINICAL RELEVANCE: For surgeons who reference the posterolateral rim for femoral tunnel placement during anterior cruciate ligament reconstruction, indistinct posterolateral rim morphology may result in errant tunnel placement. Improved awareness of posterolateral rim morphology preoperatively may help avoid technical errors with placement of the femoral tunnel.

Morphology of the femoral intercondylar notch.

BACKGROUND: During anterior cruciate ligament reconstruction, proper femoral tunnel placement is important. The purpose of the present study was to characterize the osseous anatomy of the femoral intercondylar notch. METHODS: We studied the morphology of the femoral intercondylar notch in 200 human femora from skeletally mature donors, with specific attention being paid to the morphology of the ridge on the lateral wall of the intercondylar notch and the posterolateral rim of the intercondylar notch. The distances from the posterolateral rim of the intercondylar notch to the lateral intercondylar ridge and from the posterolateral rim of the intercondylar notch to the inlet of the intercondylar notch (notch depth) were measured at the nine, ten, and eleven o'clock positions for right knees and at the one, two and three o'clock positions for left knees. RESULTS: The lateral intercondylar ridge was present in 194 femora and absent in six. The mean distance from the posterolateral rim of the intercondylar notch to the lateral intercondylar ridge was 9.0, 11.0, and 12.7 mm at the nine, ten, and eleven o'clock positions in right knees and the one, two, and three o'clock positions in left knees, respectively. We observed three different types of morphology of the posterolateral rim of the intercondylar notch. The morphology of the posterolateral rim of the intercondylar notch was distinct in 183 of 200 specimens. A distinct, straight border (type 1) was seen in 175 femora (87.5%); a distinct, V-shaped border (type 2) was seen in eight (4%); and an indistinct border (type 3) was seen in seventeen (8.5%). CONCLUSIONS: The morphology of the femoral intercondylar notch varies little. Occasionally, the posterolateral rim of the intercondylar notch is not well-defined. In these knees, accurate placement of commercial femoral tunnel aiming guides may be difficult.

Clavicular anatomy and the applicability of precontoured plates.

BACKGROUND: Plate fixation of clavicular fractures is technically difficult because of the complex anatomy of the bone, with an S-shaped curvature and a cephalad-to-caudad bow. The purpose of the present study was to characterize variations in clavicular anatomy and to determine the clinical applicability of an anatomic precontoured clavicular plate designed for fracture fixation. METHODS: One hundred pairs of clavicles were analyzed. The location and magnitude of the superior clavicular bow were determined with use of a digitizer and modeling software. Axial radiographs were made of each clavicle and the precontoured Acumed Locking Clavicle Plate, which is designed to be applied superiorly. With use of Adobe Photoshop technology, the plates were freely translated and rotated along each clavicle to determine the quality of fit and the location of the "best fit." RESULTS: The location of the maximum superior bow was lateral, with a mean distance of 37.2 +/- 18.4 mm from the acromial articulation and with a mean magnitude of 5.1 +/- 5.9 mm. There was no significant difference in the location or magnitude of the apex of the bow between specimens from male and female donors. The anatomic precontoured clavicular plate had the best fit in specimens from black male donors and the worst fit in specimens from white female donors, with a poor fit being seen in 38% (nineteen) of the fifty specimensfrom white female donors. The best location for superior plate application was along the medial aspect of the clavicle. CONCLUSIONS: The apex of the superior bow of the clavicle is typically located along the lateral aspect of the bone, whereas the medial aspect of the superior surface of the clavicle remains relatively flat, making it an ideal plating surface. The precontoured anatomic clavicular plate appears to fit the S-shaped curvature on the superior surface of the majority of clavicles in male patients but may not be as conforming in white female patients. While this plate fits in the medial three-fifths of the clavicle, it does not fit as well laterally.