Brad Yoo

Retropatellar technique for intramedullary nailing of proximal tibia fractures: A cadaveric assessment

Objective: To investigate if the radiographically correct and anatomically safe starting point and the appropriate sagittal plane vector could be obtained using a retropatellar technique for proximal tibia fractures treated with an intramedullary device. Methods: We performed a cadaveric and radiographic study utilizing 16 limbs. We performed a retropatellar approach via longitudinal quadriceps split, passed a specialized trocar through the patellofemoral joint and onto the superior aspect of the tibia, and inserted Kirschner wires into the anatomic safe zone of the tibial plateau at 0, 10, 20, 30, 40, and 50 degrees of knee flexion utilizing biplanar fluoroscopy. We recorded knee flexion with a goniometer and the entrance vector of the Kirschner wire in relation to the anterior tibial cortex. Setting: University-affiliated cadaver and anatomy laboratory. Results: There was a progressive increase in the ability to obtain the correct anatomical start site from 1 of 16 (6.25%) at full extension to 12 of 16 (75%) at 50 degrees of knee flexion (P = 0.00098). A statistically significant decrease in the average sagittal plane entrance vector in relation to the anterior tibial cortex was found from 23.1 degrees at full extension to −0.41 degrees at 50 degrees of knee flexion (P < 0.0001). Conclusions: The retropatellar technique allows the radiographically defined correct start site to be localized, particularly at higher degrees of knee flexion. More favorable intramedullary nail insertion angles were possible with the retropatellar technique, particularly with knee flexion angles greater than 20 degrees. The retropatellar technique demands further investigations to further delineate its advantages, limitations, and possible risks to local anatomy.

The retropatellar portal as an alternative site for tibial nail insertion: a cadaveric study.

Objective: To define spatial relationships between major intra-articular structures of the knee and the entry site of a tibial nail inserted using a retropatellar portal. Design: Cadaveric study using 16 fresh-frozen limbs. Setting: University-affiliated cadaver and anatomy laboratory. Results: The mean distance of the nail entry site and the medial and lateral menisci were 6.6 ± 3.2 mm and 6.4 ± 4.4 mm, respectively. The distance to the medial and lateral articular surfaces were 5.6 ± 3.6 mm and 7.4 ± 4.2 mm, respectively. The mean distance to the anterior cruciate ligament footprint was 7.5 ± 3.5 mm. The lateral meniscus was never injured during the procedure. The anterior cruciate ligament was undisturbed in all specimens. The medial meniscus was injured 1 to 2 mm in 12.5% of specimens. The intermeniscal ligament was injured 1 to 2 mm in 81.2% of the specimens. Conclusion: The intermeniscal ligament and medial meniscus are at the most risk during intramedullary nailing of the tibia using the retropatellar technique. This may be corrected by avoiding an excessively medial start point. Damage to the intermeniscal ligament and medial meniscus occurs more commonly with the retropatellar portal, but this damage was never more than 1 to 2 mm. This risk, however, appears similar to the pattern and incidence of injury that occurred in prior studies investigating tibial nail insertion through a standard patellar tendon approach. The retropatellar technique demands clinical investigation to further define both its safety and its use.

Neurovascular Risks of Anteroinferior Clavicular Plating

Anteroinferior plating has been described for internal fixation of clavicular fractures, citing improved bicortical fixation, less hardware prominence, and safer drill trajectories compared with other plate configurations. This anatomic study defined structures at risk during anteroinferior clavicular plating. Four paired cadaveric specimens (8 clavicles) from ages 75 to 93 years were systematically dissected. Using the screw paths associated with an anteroinferior plate (anteroinferior to superoposterior), the distance from the posterior clavicle cortex to the nearest vital structure was measured at 5 different positions along the clavicle. In the medial half of the clavicle, the subclavian artery is in closest proximity to the clavicle, measuring, on average, 22.95 mm and 15.10 mm at point A and B. At the lateral three-fifths point of the clavicle (point C), the brachial plexus is 12.76 mm from the posterior clavicle and is more at risk than the subclavian artery. Lateral to the three-fifth point of the clavicle, there were no vital structures that could be injured by overdrilling. Our results suggest that more care should be observed with placement of screws in the medial half of the clavicle where subclavian artery damage is more likely.

Dorsalis pedis artery pseudoaneurysm after Lisfranc surgery.

We present a 44-year-old man who sustained a Lisfranc dislocation complicated by a dorsalis pedis pseudoaneurysm. This case represents a rare complication of a commonly performed orthopaedic procedure.

Crutch Weightbearing on Comminuted Humeral Shaft Fractures: A Biomechanical Comparison of Large versus Small Fragment Fixation for Humeral Shaft Fractures

Purpose: This study evaluated the failure properties of length unstable humerii secured with small or large fragment plates. Methods: Two nonlocking plate constructs were examined, a nine-hole 4.5-mm limited contact dynamic compression plate (large fragment group) and a 12-hole 3.5-mm limited contact dynamic compression plate (small fragment group), both on composite humerii with a 1-cm defect to simulate comminution (n = 12 for each group). Each plate construct had similar working lengths and number of fixation points. Mechanical testing was first randomized for stiffness measurements in axial and torsional loads. All constructs were then tested in cyclic axial loads to failure. Results: For axial testing, the large fragment group had a mean stiffness of 1020 ± 195 N/mm compared with 268 ± 67 N/mm in the small fragment group (P < 0.0001). For torsional testing, the large fragment group had a mean stiffness of 1.5 ± 0.05 Nm/degree compared with 0.9 ± 0.04 Nm/degree in the small fragment group (P < 0.0001). Plastic deformation in the large fragment and small fragment groups were 0.09 ± 0.07 mm and 0.20 ± 0.24 mm, respectively (P = 0.1) assessed during cyclic testing up to 300 N. The postcyclic yield force in the large fragment group was 227 ± 30 N and in the small fragment group was 153 ± 5 N (P < 0.0001). The ultimate load in the large fragment and small fragment groups were 800 ± 87 N and 307 ± 15 N, respectively. Conclusion: The results corroborate anticipated plate mechanical behavior with plate stiffness increasing as both plate width and thickness increase. The calculated yield force data suggest that both small and large fragment constructs would experience plastic deformation during bilateral crutch ambulation in a patient weighing 50 kg or more. The large fragment construct is not expected to catastrophically fail when subjected to loads in a patient 90 kg or less. The small fragment construct is predicted to catastrophically fail in patients weighing 70 kg or more.

Observational Studies in Orthopaedic Surgery: The STROBE Statement as a Tool for Transparent Reporting

Evidence-based medicine in orthopaedic surgery comprises predominantly observational studies. While the gold standard of study methodology is considered to be randomized controlled trials (RCTs), observational studies provide valuable information regarding disease prevalence and etiology, rare outcomes, and adverse treatment effects. Orthopaedic surgeons care for many diseases and injuries that are rare and will likely never be the subject of an RCT. Given the bias to which observational studies are prone, however, transparent reporting is imperative. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement is a checklist of items that can help clinician-scientists to improve the transparency with which observational studies are reported. We offer the following guidelines and examples for how the STROBE statement can be applied to reporting observational studies in orthopaedic surgery. Observational studies inform clinicians about disease etiology, natural history, prognostic factors, and treatment effectiveness1,2. The most common observational study designs include cohort, case-control, and cross-sectional studies. In a cohort study, subjects are divided into two groups, or cohorts: those with an exposure of interest and those without. The groups are then followed prospectively and are observed for an outcome of interest. In a case-control study, subjects who have experienced an outcome (cases) are matched with subjects who have not experienced an outcome (controls). The two groups are then studied retrospectively to determine a causal relationship between unmatched risk factors and the outcome of interest. In a cross-sectional study, each subject in a population is evaluated at a single point in time, often to calculate the prevalence of disease or to establish an association between risk factors and outcome. Observational studies, specifically, case series, predominate the surgical literature in both general surgery (46%) and orthopaedic surgery (88%)2-4. One reason for the high prevalence of observational studies …

Unusual Variant of the Nutcracker Fracture of the Calcaneus and Tarsal Navicular

A 62-year-old woman with severe seizure disorder presented with right ankle and foot pain after being found down, presumably following a seizure recurrence. Imaging showed an acute comminuted fracture of the anterolateral aspect of the right calcaneus, as well as an acute avulsion fracture of the right navicular tuberosity at the site of insertion of the tibialis posterior tendon. This fracture pattern suggests forced abduction of the midfoot or forefoot with severe compression of the lateral column and failure of the medial column under tension, an entity that has previously been described as the nutcracker fracture. This mechanism of injury should prompt particularly careful evaluation of the navicular, cuboid, and calcaneus for any signs of injury. Subtle fractures of the navicular and calcaneus may be overlooked in the emergency setting, leading to a delay in surgical treatment and ultimately chronic foot deformities that can result in significant functional disability.