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A low-lying peroneus brevis muscle belly has been described as a risk factor for the development of peroneal tendon pathology, but this finding has primarily been described based on cohorts with pre-existing clinical findings. Therefore, the objective of this investigation was to evaluate the frequency of apparently abnormal low-lying muscle bellies from a series of subjects without clinical or imaging findings of peroneal tendon pathology. One hundred consecutive MRIs were reviewed with measurement of the distance from the distal peroneal myotendinous junction to the tip of the fibula. This distance was observed to be 23.9 ± 8.8 mm (10.8-55.4 mm; 95% confidence interval 22.2-26.7 mm). If one assumed that a myotendinous junction within 2 cm of the distal tip of fibula represented an abnormal low-lying muscle, then we observed 37% of extremities without clinical or radiographic evidence of peroneal tendon pathology that would be considered anatomically "abnormal." When a low-lying muscle belly was defined as occurring within 2 cm of the distal tip of the fibula, then a probability analysis of our data distribution found a 32.6% probability for individuals to have an "abnormally" low-lying muscle belly. These results indicate that what has traditionally been defined intraoperatively as an abnormally low-lying peroneus brevis muscle belly might simply represent intraoperative confirmation bias of relatively normal structural anatomy.

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The objective of this investigation was to analyze the surgical anatomy of the endoscopic gastrocnemius recession procedure with reference to the curved nature of the aponeurosis. A consecutive series of 34 magnetic resonance imaging scans were evaluated under the direction of a musculoskeletal radiologist. An angular calculation of the effective curvature of the aponeurosis was measured 2 cm distal to the musculotendinous junction based on the maximal posterior excursion and terminal medial and lateral edges. A frequency count was additionally performed of the number of deep intramuscular septa extending from the aponeurosis, as well as a description of the location of the neurovascular bundle in this location. The mean effective curvature was 126.5 degrees (standard deviation [SD] = 6.3 degrees, range 115-143 degrees, 95% confidence interval 124.3-128.7 degrees). We observed an average of 1.2 (SD = 0.5, range = 0-2) deep intramuscular septa extending from the aponeurosis, and that 20.6% of neurovascular bundles were located superficial to the aponeurosis in this location. In conclusion, we found that a straight cannula needs to be navigated around an approximate 125-degree angle during performance of the EGR procedure. We think that this information provides evidence of potentially unrecognized complications of this procedure and leads to future investigations demonstrating anatomic and procedural outcomes.

Assuntos

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The patellar tendon is an integral part of the knee extensor mechanism and has been historically described as a single tendon. A doubled patellar tendon is an exceedingly rare finding. We present a case of a crossed doubled patellar tendon in a 70-year-old male with a history of right knee pain, which to our knowledge has only been reported once before in the literature. The presence of a doubled patellar tendon has a potential influence on surgical planning and in the etiology of anterior knee pain.

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PURPOSE: Compression of the sciatic nerve in its path along the piriformis muscle can produce sciatica-like symptoms. There are 6 predominant types of sciatic nerve variations with type 1 being the most common (84.2%), followed by type 2 (13.9%). However, there is scarce literature on the prevalence of sciatic nerve variation in those diagnosed with sciatica. MATERIALS AND METHODS: The charts of 95 patients clinically diagnosed with sciatica who had a magnetic resonance imaging of the pelvis/hip were retrospectively studied. All patients had T1-weighted axial, coronal, and sagittal images. Magnetic resonance imagings were interpreted separately by 2 board-certified fellowship-trained musculoskeletal radiologists to identify the sciatic nerve variant. RESULTS: Seven cases were excluded because of inadequate imaging. Of the remaining 88 patients, 5 had bilateral sciatica resulting in a sample size of 93 limbs. Fifty-two (55.9%) had type 1 sciatic nerve anatomy, 39 (41.9%) had type 2, and 2 (2.2%) had type 3. The proportions of type 1 and 2 variations were significantly different from the normal distribution (P < 0.001), whereas type 3, 4, 5, and 6 variants were not (P = 1.00). CONCLUSIONS: There is strong statistical significance regarding the relationship between sciatic nerve variation and the clinical diagnosis of sciatica. Preoperative magnetic resonance imaging can be considered in sciatica patients to prevent iatrogenic injury in pelvic surgery.

Assuntos

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INTRODUCTION: Technologic advances have reduced medical radiation exposure while maintaining image quality. The purpose of this study was to determine the effects of the presence of total hip arthroplasty implants, compared with native hips, on radiation exposure of the most radiosensitive organs when manual and automatic exposure control settings are used. METHODS: Detection probes were placed at six locations (stomach, sigmoid colon, right pelvic wall, left pelvic wall, pubic symphysis, and anterior pubic skin) in a cadaver. Radiographs were obtained with the use of manual and automatic exposure control protocols, with exposures recorded. A total hip arthroplasty implant was placed in the cadaver, probe positioning was confirmed, and the radiographs were repeated, with exposure values recorded. RESULTS: The control probe placed at the stomach had values ranging from 0.00 mSv to 0.01 mSv in protocols with and without implants. With the manual protocol, exposures in the pelvis ranged from 0.36 mSv to 2.74 mSv in the native hip and from 0.33 mSv to 2.24 mSv after implant placement. The increases in exposure after implant placement, represented as relative risk, were as follows: stomach, 1.000; pubic symphysis, 0.818; left pelvic wall, 1.381; sigmoid colon, 1.550; right pelvic wall, 0.917; and anterior pubic skin, 1.015. With automatic exposure control, exposures in the pelvis ranged from 0.07 mSv to 0.89 mSv in the native hip and from 0.21 mSv to 1.15 mSv after implant placement. With automatic exposure control, the increases in exposure after implant placement, represented as relative risk, were as follows: stomach, 1.000; pubic symphysis, 1.292; left pelvic wall, 1.476; sigmoid colon, 2.182; right pelvic wall, 3.000; and anterior pubic skin, 1.378. DISCUSSION: The amount of radiation to which patients are exposed as a result of medical procedures or imaging, and whether exposure is associated with an increased risk of malignant transformation, are the subject of ongoing debate. We found that after insertion of a total hip arthroplasty implant, exposure values increased threefold at some anatomic locations and surpassed 1 mSv, the generally accepted threshold for concern. CONCLUSION: Radiation exposure to radiosensitive organs increased up to threefold after total hip implantation with automatic exposure control and up to approximately 1.5 times with the manual protocol. Doses were greater with manual exposures than with automatic exposure control (except at the control probe on the stomach, where exposure was negligible, as expected). However, after implant placement, doses increased more with automatic exposure control than with manual exposure. This difference can be attributed to increased scatter and the difficulty of dose modification because of the density of the implant. Current radiographic protocols should be reassessed to determine if the benefits of frequent radiographs outweigh the newly demonstrated risks.

Assuntos

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OBJECTIVES: To determine whether a substantially lowered radiation protocol would provide satisfactory information for the surgeon, using the distal tibia as a model. METHODS: Eleven adult cadaveric distal tibia specimens were used to create Orthopaedic Trauma Association (OTA/AO) 43C distal tibia fractures with varying displacements in 2 planes. Each specimen was scanned at 3 modified protocols, which were then subsequently read by both qualified attending orthopaedists and midlevel residents. Observer reliability was evaluated, as well as confidence levels of identifying fracture pattern and treatment protocols. RESULTS: On average, there was less than a millimeter of variability in the measured gap to true gap as a whole (mean = 0.74 mm, P < 0.0001). With regard to measurements in gap, pattern, and treatment plans, no significant difference was found between CT images acquired with standard (110 mAs) compared with medium (60 mAs; mean 0.0 mm, P = 1.0; k = 0.14, P = 0.56; k = 0.38, P = 0.13, respectively) and low protocols (45 mAs; mean 0.01 mm, P = 0.95; k = 0.24, P = 0.32; k = 0.31, P = 0.13, respectively). Furthermore, no significant difference was found in measuring step-off across standard, medium, and low radiation dose (0.21 mm, P = 0.46; 0.28 mm, P = 0.39; -0.16 mm, P = 0.48, respectively). CONCLUSION: The results of this study show no significant difference when evaluating current standard and low-dose CT scans using less than one-half the amount of exposure. This suggests that in complex extremity fractures, a new CT protocol may potentially be used. Our initial data show promise that we may retain satisfactory imaging to formulate a treatment plan while also reducing the collective radiation burden to the population.

Assuntos