3D-Printed Model in Preoperative Planning of Sciatic Nerve Decompression Because of Heterotopic Ossification: A Case Report.

CASE: A 31-year-old patient presented with an encapsulated sciatic nerve secondary to extensive hip heterotopic ossification (HO), which prevented visualization of a safe osteotomy site to avoid nerve damage. The 3D-printed model demonstrated an easily identifiable osseous reference point along the inferior aspect of the heterotopic mass, allowing for a vertical osteotomy to be safely performed. CONCLUSION: HO is associated with loss of normal anatomic topography. The current case report illustrates the use of a 3D-printed model to identify pertinent anatomic landmarks required for safe decompression of an encapsulated sciatic nerve within the anatomic region of the hip.

Interference Kirschner wires augment distal humeral fracture fixation in the elderly.

OBJECTIVES: This study was designed to compare the biomechanical stability of a two-plate distal humerus fixation with and without Kirschner-wire (K-wire) augmentation of supracondylar osteotomies. DESIGN: Ex vivo paired cadaveric study. SETTING: Biomechanical laboratory. MATERIALS: : Five pairs of fresh, elderly cadaveric humeri. INTERVENTION: Two 3.5-mm reconstruction plates were used to stabilize each humerus. This fixation model was selected solely to evaluate the effect of K-wire augmentation. Augmentation consisted of 2 K-wires placed in both the medial and lateral columns of the humerus to interdigitate with the plate screws. A posteriorly directed load was cyclically applied to the distal fragment for 5000 cycles or until failure, and osteotomy site motion was tracked optically. MAIN OUTCOME MEASUREMENTS: Fixation survival was defined as 5000 cycles or the number of cycles until osteotomy site motion reached >2 mm. RESULTS: K-wire augmented fixations survived significantly more cycles than did controls (4410 +/- 875 vs. 1114 +/- 2182, respectively; paired t test, P < 0.05). CONCLUSIONS: Augmentation with K-wires may decrease the incidence of loss of fixation in distal humeral fractures.

Biomechanical evaluation of intramedullary nail versus tension band fixation for transverse olecranon fractures.

OBJECTIVES: To compare the biomechanical stability of an alternative custom-designed intramedullary nail (IMN) fixation with that of traditional tension band wiring (TBW), the gold standard for stabilizing transverse olecranon fractures. DESIGN: Ex vivo biomechanical study. SETTING: Biomechanical laboratory. MATERIALS: Six pairs of elderly cadaver elbows. INTERVENTION: A simulated transverse olecranon fracture was created in each elbow after it had been denuded of most of its soft tissue. The right and left olecranons of each pair were alternately assigned to the IMN or TBW group. A tensile force was applied via the triceps tendon while the elbow was secured in 90 degree of flexion. MAIN OUTCOME MEASUREMENTS: Displacement at the simulated fracture segment was measured optically. Fixation failure was defined as >2 mm of fracture displacement. The differences in stiffness and maximum load to failure between the two treatments were analyzed for significance (P < 0.05) using a one-tailed paired t test. RESULTS: IMN fixation was significantly stiffer and stronger than TBW fixation. CONCLUSIONS: The locked IMN provided stronger and stiffer fixation than did TBW. Theoretically the IMN fixation would require less surgical exposure and would be expected to require fewer revisions than TBW fixation. IMN fixation warrants consideration as a clinical alternative to TBW.

Design concepts and early utilization of a new femoral interlocking nail.

Interlocking nails provide excellent stability and control of femoral fractures from the hip to the supracondylar regions, yielding excellent clinical results. Advances in femoral nail design have provided for increased variability in their applications, allowing surgeons to stabilize a wide variety of fractures through either antegrade or retrograde nail insertion methods. In the past, nails were manufactured to be implanted with a specified insertion technique, requiring the surgeon to become facile with multiple nail systems to care for the entire spectrum of femoral injuries. A new femoral intramedullary nail system is being introduced with the capability of stabilizing both right- and left-sided femoral fractures in all 3 modes of interlocking--that is, first-generation antegrade nailing, second-generation reconstruction nailing, and retrograde nailing. The design and rationale of this system are discussed, and clinical examples of use of this new device are provided.