Bridge Plate Fixation of Distal Femur Fractures: Defining Deficient Radiographic Callus Formation and Its Associations.

OBJECTIVE: To determine whether deficient early callus formation can be defined objectively based on the association with an eventual nonunion and specific patient, injury, and treatment factors. METHODS: Final healing outcomes were documented for 160 distal femur fractures treated with locked bridge plate fixation. Radiographic callus was measured on postoperative radiographs until union or nonunion had been declared by the treating surgeon. Deficient callus was defined at 6 and 12 weeks based on associations with eventual nonunion through receiver-operator characteristic analysis. A previously described computational model estimated fracture site motion based on the construct used. Univariable and multivariable analyses then examined the association of patient, injury, and treatment factors with deficient callus formation. RESULTS: There were 26 nonunions. The medial callus area at 6 weeks <24.8 mm 2 was associated with nonunion (12 of 39, 30.8%) versus (12 of 109, 11.0%), P = 0.010. This association strengthened at 12 weeks with medial callus area <44.2 mm 2 more closely associated with nonunion (13 of 28, 46.4%) versus (11 of 120, 9.2%), P <0.001. Multivariable logistic regression analysis found limited initial longitudinal motion (OR 2.713 (1.12-6.60), P = 0.028)) and Charlson Comorbidity Index (1.362 (1.11-1.67), P = 0.003) were independently associated with deficient callus at 12 weeks. Open fracture, mechanism of injury, smoking, diabetes, plate material, bridge span, and shear were not significantly associated with deficient callus. CONCLUSION: Deficient callus at 6 and 12 weeks is associated with eventual nonunion, and such assessments may aid future research into distal femur fracture healing. Deficient callus formation was independently associated with limited initial longitudinal fracture site motion derived through computational modeling of the surgical construct but not more routinely discussed parameters such as plate material and bridge span. Given this, improved methods of in vivo assessment of fracture site motion are necessary to further our ability to optimize the mechanical environment for healing. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Reduction and fixation of high-energy proximal tibiofibular joint dislocations: a technical trick.

We present our technique for screw stabilization and our clinical experience treating a series of patients presenting with proximal tibiofibular joint fracture-dislocations.

The effect of proximal tibiofibular joint dislocation on knee mechanics: reduction and fixation matters.

PURPOSE: Proximal tibiofibular joint (PTFJ) dislocations are under-investigated injuries. There is scant basic science or clinical evidence to direct management. The purpose of this study was twofold; first to investigate the pathomechanics of PTFJ dislocation on knee mechanics. The second purpose was to evaluate knee mechanics following reduction and fixation. METHODS: Six cadaveric legs were tested on a mechanical platform. A 5 Nm external rotation force was applied to each knee and the external rotation and fibular translation was measured for several study conditions at 0°, 30°, and 90° of flexion. Conditions included: the native state, transection of the posterior PTFJ ligament, transection of the anterior and posterior ligaments, screw fixation, and suspensory fixation. Screw fixation was performed using a single quadricortical 3.5 mm screw. Suspensory fixation was performed using an Arthrex TightRope device RESULTS: Transection of the anterior and posterior ligaments increased external rotation by 4.3°, 5.9°, and 5.6°, at 0°, 30°, and 90° (p ≤ 0.001), respectively. Screw and suspensory fixation returned external rotation to a near native state with mild overconstraint. Complete transection of anterior and posterior ligaments resulted in pathologic anterior fibular translation of 1.51 mm (p = 0.001), 1 mm, (p = 0.02) and 0.44 mm (p = 0.69) for 0°, 30°, 90° of knee flexion. Screw and suspensory fixation restored native translation at all points with a small degree of overconstraint. CONCLUSION: Disruption of the PTFJ causes pathologic external rotation and anterior fibular translation. Fixation restores near native motion with minor overconstraint. Surgeons should consider reduction and fixation of PTFJ injuries to restore native knee mechanics.

Does a Medial Malleolar Osteotomy or Posteromedial Approach Provide Greater Surgical Visualization for the Treatment of Talar Body Fractures?

BACKGROUND: Surgical management of talar body fractures is influenced by soft-tissue condition and fracture pattern. Two common surgical approaches for the treatment of talar body fractures are the medial malleolar osteotomy (MMO) and the posteromedial approach (PMA). The purpose of this study was to compare the observable talar body surface area with the MMO and the PMA. We hypothesized that visualization following a PMA improves with distraction and distraction with a gastrocnemius recession. METHODS: Five pairs of cadaver limbs were used. Each pair of specimens underwent both approaches to act as an internal control. The laterality of the PMA was determined by randomization, and the MMO was performed on the contralateral ankle. The PMA was performed to visualize the talus, and the talar surface area was recorded using a handheld 3D surface scanner. A distractor was then placed across the joint, and the surface area was remeasured. Finally, a gastrocnemius recession was performed, and the measured surface area under the distraction was recorded. The MMO was performed in standard fashion using fluoroscopy, and the observable talar surface area was recorded. Scans were performed twice for each approach, and the surface areas were averaged. The talus was excised and scanned after each approach in order to compare the visualized surface area with the total surface area of the native talus. RESULTS: The MMO and the PMA exposed a mean of 11.2 and 6.7 cm2, respectively, of the talar surface. Visualization with the PMA was improved with distraction, revealing 8.3 cm2 of the talus (p = 0.01 when compared with an isolated PMA). A PMA with distraction and gastrocnemius recession exposed 9.9 cm2 of the talar dome and body. There was no significant difference in exposure between the MMO and the PMA with distraction and gastrocnemius recession (p = 0.32). CONCLUSIONS: The MMO and the PMA both afford excellent visualization for reduction and fixation of talar body fractures. Visualization using the PMA is improved with distraction and distraction with a gastrocnemius recession. The results of this study may assist surgeons in selecting the optimal approach for surgical repair of talar body fractures.