Who is in danger? Impingement and penetration of the anterior cortex of the distal femur during intramedullary nailing of proximal femur fractures: preoperatively measurable risk factors.

BACKGROUND: Intramedullary nail (IMN) perforation through the cortex of the distal femur is a risk of intramedullary stabilization of proximal femur fractures. This study was performed to identify information that is available before operation that can pick out patients at risk for this complication. METHODS: A retrospective review of records and roentgenograms of 150 patients treated with intramedullary stabilization of a proximal femur fracture during a 4-year period at a Level I trauma center was performed. The position of the tip of the IMN in the distal femur was measured on postoperative lateral roentgenograms and grouped into anterior, middle, or posterior one third positions. Patients in whom the tip of the nail contacted or penetrated through the anterior cortex were designated as having cortical impingement. RESULTS: Nail tip position was in the anterior one third of the distal femur in 71 (47%) of 150 patients, and 38 (25%) of these patients fit the definition for cortical impingement. The radiographic femoral angle of incidence strongly correlated with an anterior nail tip position (p < 0.0001) and cortical impingement (p < 0.0001). Shorter patients were also more likely to have cortical impingement (p < 0.005), and patients less than 160 cm in height had a 49% likelihood of impingement. A starting point in the posterior one third of the greater trochanter increased the likelihood of having an anterior nail tip position as well (p < 0.007). CONCLUSION: Of the 150 patients in whom an IMN was used for stabilization of a proximal femur fracture, 71 (47%) had the distal part of their nail positioned in the anterior one third of the distal femur. Patients who are shorter and/or had an increased femoral bow as measured on a lateral roentgenogram are more likely to have an anterior nail tip position or cortical impingement. Posterior starting points should be avoided to prevent this complication. LEVEL OF EVIDENCE: Prognostic study, level III; therapeutic study, level IV.

Fabella fracture with CT imaging: a case report.

Fracture of the fabella is rare, may be easily overlooked, and can be a clinically important cause of posterolateral knee pain following traumatic injury or total knee arthroplasty. To date, nine case reports of fabella fracture with radiographic documentation have been reported in the literature. This report documents a 55-year-old male pedestrian who was struck by an automobile and presented with radiographs demonstrating depressed lateral tibial plateau and proximal fibula fractures. Computed tomography (CT) was performed for surgical planning and demonstrated the additional finding of a radiographically occult nondisplaced fabella fracture. To the best of our knowledge, this is the first case in which CT documentation of a fabella fracture is reported. Fracture of the fabella is a rare but important clinical entity which may be overlooked clinically and radiographically. Clinical information can provide a high index of suspicion, and when coupled with radiographic and CT findings, may lead to the correct diagnosis. CT imaging of the knee may confirm a suspected fabella fracture or may help detect a radiographically occult fracture.

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.

Biomechanical evaluation of locking plate radial shaft fixation: unicortical locking fixation versus mixed bicortical and unicortical fixation in a sawbone model.

PURPOSE: Compression plating is a commonly accepted technique for treating diaphyseal forearm fractures. The purpose of this study was to evaluate the stabilizing effects of two hybrid fixations that replace the end screws of a locked unicortical fixation with bicortical (locked or unlocked) screws and to compare these hybrid fixations to an unlocked bicortical fixation. METHODS: Sixteen composite radius sawbones were equally divided into 4 groups. We performed a midshaft osteotomy and plate fixation on the volar surface with 1 of 4 different constructs: 3 unlocked bicortical screws on each side (unlocked bicortical), 3 locked unicortical screws on each side (locked unicortical), or with 2 unicortical locked screws near the fracture and 1 bicortical unlocked (unlocked hybrid) or locked (locked hybrid) screw distant from the fracture on each end (LCP system, Synthes USA, Paoli, PA). Specimens were tested in nondestructive 4-point bending and torsion on a servo-hydraulic material testing system. The construct stiffness was obtained from the linear portion of the load-displacement curves after 3 cycles of preconditioning. The results from all groups were compared using analysis of variance and post hoc Bonferroni tests. RESULTS: Under torsional loads, replacing the end screws of a locked unicortical configuration with bicortical screws significantly improved the construct stiffness: 57.6% increase for the locked screws and 51.6% increase for the unlocked. In anteroposterior (AP) bending, the highest improvement over the locked unicortical configuration came from the locked hybrid constructs (42.9% increase). When compared with the unlocked bicortical configuration, both hybrid constructs provide equivalent stability in torsion but superior stability in AP bending. CONCLUSIONS: Replacing a single set of unicortical locked screws with locked or unlocked bicortical screws distant from the fracture site improves torsional stability of the construct by more than 50%, giving stability equal to standard unlocked plating. The hybrid fixation, however, with locked bicortical end screws has the best stability in AP bending.