Jonathan G. Eastman

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.

Correlating preoperative imaging with intraoperative fluoroscopy in iliosacral screw placement.

BackgroundPercutaneous iliosacral screw placement can successfully stabilize unstable posterior pelvic ring injuries. Intraoperative fluoroscopic imaging is a vital component needed in safely placing iliosacral screws. Obtaining and appropriately interpreting fluoroscopic views can be challenging in certain clinical scenarios. We report on a series of patients to demonstrate how preoperative computed tomography (CT) imaging can be used to anticipate the appropriate intraoperative inlet and outlet fluoroscopic views.Materials and methods24 patients were retrospectively identified with unstable pelvic ring injuries requiring operative fixation using percutaneous iliosacral screws. Utilizing the sagittal reconstructions of the preoperative CT scans, anticipated inlet and outlet angle measurements were calculated. The operative reports were reviewed to determine the angles used intraoperatively. Postoperative CT scans were reviewed for repeat measurements and to determine the location and safety of each screw.ResultsPreoperative CT scans showed an average inlet of 20.5° (7°–37°) and an average outlet of 42.8° (30°–59°). Intraoperative views showed an average inlet of 24.9° (12°–38°) and an average outlet of 42.4° (29°–52°). Postoperative CT scans showed an average inlet of 19.4° (8°–31°) and an average outlet of 43.2° (31°–56°). The average difference from preoperative to intraoperative was 4.4° (−21° to 5°) for the inlet and 0.45° (−9° to 7°) for the outlet. The average difference between the preoperative and postoperative CT was 2.04° (0°–6°) for the inlet and 2.54° (0°–7°) for the outlet.ConclusionThere is significant anatomic variation of the posterior pelvic ring. The preoperative CT sagittal reconstruction images allow for appropriate preoperative planning for anticipated intraoperative fluoroscopic inlet and outlet views within 5°. Having knowledge of the desired intraoperative views preoperatively prepares the surgeon, aids in efficiently obtaining correct intraoperative views, and ultimately assists in safe iliosacral screw placement.Level of evidenceIV, Retrospective case series.

Entrapped Posteromedial Structures in Pilon Fractures

Objectives: To analyze a patient cohort who sustained a tibial pilon fracture and report the incidence of interposed posteromedial soft tissue structures. Design: Retrospective cohort review. Setting: Regional Level 1 Trauma Center. Patients/Participants: About 394 patients with 420 pilon fractures treated between January 2005 and November 2011. Intervention: Each patients preoperative radiographs and computed tomography (CT) images were reviewed. The axial and reconstructed images were used in bone and soft tissue windows to identify any posteromedial soft tissue structures incarcerated within the fracture. Main Outcome Measurements: Medical charts reviewed for the presence of preoperative neurologic deficit, separate posteromedial incision, and whether attending radiology CT interpretation noted the interposed structure. Results: 40 patients with 40 fractures (9.5%) had an entrapped posteromedial structure. The tibialis posterior tendon was interposed in 38/40 fractures (95%) and the posterior tibial neurovascular bundle in 4/40 fractures (10%). Preoperative neurologic deficit occurred in 5/40 patients (12%). A posteromedial incision was used in 11/40 fractures (27%). The attending radiology CT interpretation noted the interposed structure in 8/40 fractures (20%). Conclusions: In addition to the osseous injuries, CT imaging can demonstrate the posteromedial soft tissue structures. In our series, the tibialis posterior tendon was commonly incarcerated. In some cases, removal of the entrapped structure(s) may not be possible through the more commonly used anterolateral and anteromedial surgical approaches, and a separate posteromedial exposure may be required. Failure to recognize the presence of an interposed structure could lead to malreduction, impaired tendon function, neurovascular insult, and the need for further surgery. Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Injury to neurovascular structures with insertion of traction pins around the knee

OBJECTIVE Identify risk to neurovascular structures around the knee with placement of skeletal traction pins. METHODS Kirchner wires were inserted into cadaveric limbs followed by layer dissecting of each leg. Correlations between weight, height, BMI, and distance were determined after calculating the average distance with deviation between each anatomic structure and the Kirschner wire. CONCLUSION Insertion of traction pins around the knee did not result in injury to neurovascular structures. Both weight and BMI positively correlated with distance between implants and neurovascular structure. Data collected suggests similar trends for all other anatomic structures.

A Useful Preoperative Planning Technique for Transiliac-Transsacral Screws

Stabilization of posterior pelvic ring injuries is increasingly performed using percutaneously placed iliosacral and transiliac-transsacral screws. Understanding the unique and specific anatomical variations present in each patient is paramount. Multiple methods of evaluating potential osseous fixation pathways for screw placement exist, but many require specific imaging protocols, specialized software, or modification of data. Not all surgeons and institutions have access to these options for a variety of reasons. A simple technique to preoperatively plan for safe transiliac-transsacral screws is proposed.

Heterotopic ossification around the knee after tibial nailing and ipsilateral antegrade and retrograde femoral nailing in the treatment of floating knee injuries

PurposeFloating knee injuries are relatively uncommon injuries. We report the prevalence, location, and severity of heterotopic ossification (HO) around the knee in patients treated with antegrade tibial intramedullary nailing and ipsilateral antegrade versus retrograde femoral intramedullary nailing as well as how the severity of HO around the knee affects knee range of motion (ROM).MethodsFrom 2004 to 2014, 26 floating knee injuries were included. Radiographs were reviewed to determine presence, location, and severity of HO. Post-operative knee ROM was determined.ResultsA significantly higher prevalence of HO around the knee was detected in the retrograde group (90%) compared to the antegrade group (43%) (p = 0.028). There was a trend for more HO into the patellar tendon occurring in 29% of patients in the antegrade group and 74% in the retrograde group (p = 0.069). The severity of HO was higher for the retrograde group 1.6 ± 1.0 compared to the antegrade group 0.4 ± 0.5 (p = 0.004). There was poor correlation between HO severity and knee ROM.ConclusionsTreatment of floating knee injuries with a retrograde femoral nail was demonstrated to result in a greater likelihood of developing HO and a greater severity of HO around the knee than if treated with an antegrade femoral nail. However, this increased severity of HO is unlikely to affect ROM.Level of evidence: III.

Is S3 a Viable Osseous Fixation Pathway

Objectives: To report the incidence of patients with a third sacral segment (S3) osseous fixation pathway (OFP) that could accommodate a transiliac-transsacral screw. Design: Retrospective case series. Setting: Regional Level 1 Trauma Center. Patients/Participants: A total of 250 patients without pelvic trauma from January 2017 to February 2017 were included. Intervention: The axial and sagittal reconstruction images of each patients computed abdomen and pelvis tomography (CT) scans were reviewed. Main Outcome Measurements: Each CT was evaluated for the presence of sacral dysmorphism and whether an S3 OFP that could accommodate an intraosseous transiliac-transsacral screw exists. Results: There were 130 of the 250 patients (52%) with sacral dysmorphism. Overall, 38 of the 250 patients (15.2%) had an S3 OFP that could accommodate a 7.0-mm transiliac-transsacral style screw. When narrowed to patients who had an S3 OFP, 38 of 153 patients (24.8%) could accommodate a 7.0-mm transiliac-transsacral screw. Specific to the 38 patients with an adequate S3 OFP, 34 of 38 patients (89.5%) were noted to have sacral dysmorphism. Conclusions: Our study demonstrates that 15.2% of patients have an S3 OFP large enough to accommodate an intraosseous implant. Patients who have sacral dysmorphism are more likely to have an adequate S3 OFP. Additional studies are needed to quantify the S3 OFP, understand the bone quality of the S3 segment and accompanying biomechanical implications, and investigate the anatomical concerns associated with S3 screw placement. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Early failure of symphysis pubis plating

INTRODUCTION Operative fixation of a disrupted symphysis pubis helps return alignment and stability to a traumatized pelvic ring. Implant loosening or failure has been demonstrated to commonly occur at some subacute point during the postoperative period. The purpose of this study is to report on a series of patients with traumatic pelvic ring disruptions to determine the incidence and common factors associated with early postoperative symphyseal plate failure before 7 weeks. MATERIALS AND METHODS 126 patients retrospectively identified with unstable pelvic injuries treated with open reduction and plate fixation of the symphysis pubis and iliosacral screw fixation. Preoperative and postoperative radiographs, computed tomography (CT) images, and medical chart were reviewed to determine symphyseal displacement preoperatively and postoperatively, time until plate failure, patient symptoms and symphyseal displacement at failure, subsequent symphyseal displacement, incidence of additional surgery, and patient weight bearing compliance. RESULTS 14 patients (11.1%) sustained premature postoperative fixation failure. 13 patients had anteroposterior compression (APC)-II injuries and 1 patient had an APC-III injury. Preoperative symphyseal displacement was 35.6 millimeters (mm) (20.8-52.9). Postoperative symphyseal space measurement was 6.3mm (4.7-9.3). Time until plate failure was 29days (5-47). Nine patients (64.2%) noted a pop surrounding the time of failure. Symphyseal space measurement at failure was 12.4mm (5.6-20.5). All patients demonstrated additional symphyseal displacement averaging 2.6mm (0.2-9.4). Two patients (14.2%) underwent revision. Four patients (28.5%) were non-compliant. CONCLUSION Premature failure of symphysis pubis plating is not uncommon. In this series, further symphyseal displacement after plate failure was not substantial. The presence of acute symphyseal plate failure alone may not be an absolute indication for revision surgery. Making patient education a priority could lead to decreased postoperative non-compliance and potentially a decreased incidence of implant failure. Posterior pelvic ring fixation aides overall pelvic ring stability and may help minimize further displacement after early postoperative symphyseal plate failure. Further functional outcome and biomechanical studies surrounding early symphyseal plate failure are needed.