Reduction and Stabilization of Depressed Articular Tibial Plateau Fractures: Comparison of Inflatable and Conventional Bone Tamps: Study of a Cadaver Model.

BACKGROUND: Restoration of articular congruity and mechanical integrity of subchondral bone are important surgical goals of the treatment of intra-articular fractures. The purpose of this study was to compare the reduction quality and biomechanical integrity between cadaveric intra-articular tibial plateau fractures reduced with an inflatable bone tamp and contralateral fractures reduced with a series of cylindrical conventional metal bone tamps. METHODS: A standardized lateral tibial plateau split-depression fracture was created in each leg of fourteen pairs of cadaver legs. In each pair, the fracture on one side was reduced under fluoroscopy with use of an inflatable bone tamp and the fracture on the contralateral, control side was reduced with conventional bone tamps and a mallet. Any residual bone defects were filled with calcium phosphate bone-void filler. The constructs were stabilized with a lateral tibial plateau buttress plate. Each articular reduction was qualitatively graded by blinded observers using fluoroscopic images, three-dimensional computed tomography (CT) scans, and visual inspection of the articular surface. Quantitative volumetric analysis was performed to calculate under-reduction, over-reduction, and total malreduction volumes. Each reduced fracture was cyclically loaded and then statically loaded to failure under axial compression, and the strength and stiffness of the constructs were compared between sides. RESULTS: The majority (eleven) of the fourteen fractures reduced with the inflatable bone tamp were rated as having a better reduction than the contralateral fracture reduced with the conventional bone tamps. The median over-reduction and malreduction in the inflatable-tamp group (7% and 21.6%, respectively) were significantly less than those in the conventional-tamp group (19.2% and 47.1%), although the median under-reduction (6.2% in the inflatable-tamp group and 9.6% in the conventional-tamp group) did not differ significantly between groups. The fractures reduced with the inflatable tamp displaced less during cyclic loading than those reduced with the conventional tamp. Median static stiffness and yield load were also significantly higher in the inflatable-tamp group (880 N/mm and 704 N) than in the conventional-tamp group (717 N/mm and 641 N). CONCLUSIONS: As compared with contralateral control fractures treated with conventional bone tamps, fractures treated with an inflatable bone tamp had qualitatively and quantitatively better reduction, typically resulting in a smoother articular surface with less residual defect volume. Fractures reduced with an inflatable bone tamp exhibited less subsidence during cyclic loading and greater stiffness under static loading compared with those treated with conventional bone tamps. CLINICAL RELEVANCE: Using an inflatable bone tamp in association with calcium phosphate bone-void filler to reduce and maintain reduction of an articular fracture may help in achieving the surgical goal of a more anatomic reduction with better resistance to subsidence.

An examination and discussion of unintended consequences of being an employed physician.

Medicine's landscape is ever changing. The working model in which an orthopaedic surgeon operates is no exception. These models can be very confusing for the orthopaedic surgeon who has little training in the area of business, but especially to the young orthopaedic surgeon who has focused their efforts nearly 100% on medical training over many years. This article examines some of the issues that might not be obvious to the physician who is trying to decide between hospital employment and private practice or some combination thereof. Also, there are several discussion points and questions raised for the physician contract negotiator when examining an employment contract. Finally, introduced are some advocacy steps that we, as orthopaedic surgeons, should consider to continue to improve medicine and our work environments.

Subjective and novel objective radiographic evaluation of inflatable bone tamp treatment of articular calcaneus, tibial plateau, tibial pilon and distal radius fractures.

There is a growing need to develop tools that allow for better reductions of difficult to treat fractures in minimally disruptive ways. One such technique has been developed using the inflatable bone tamp and a fast setting calcium phosphate. KYPHON(®) XPANDER Inflatable Bone Tamp and the KYPHON(®) Osteo Introducer(®) System were used to reduce the articular fractures and a fast-setting calcium phosphate was introduced into those voids and metal hardware was applied as deemed necessary. Subjects were skeletally mature patients treated for articular fractures of the calcaneus, tibial plateau, tibial pilon, or distal radius. Post-operative day zero and week 12 radiographs were objectively and subjectively evaluated by three independent orthopaedic surgeons. Their objective scores were then translated into subjective categories based on the Heiney-Redfern scaled scoring (H-R score) system established herein. Overall, the thorough radiographic analysis by independent reviewers indicates that the technique is capable of obtaining and maintaining articular reductions in a good or adequate manner at 12-weeks post-operatively. Introduced is a potential novel evaluation scale scoring system for these articular fractures that evaluates the important anatomic considerations reproducibly in fracture reductions. There are many potential benefits that remain speculative to this type of tool within a procedure, and therefore this tool and technique warrants further research.

Percutaneous inflation osteoplasty for indirect reduction of depressed tibial plateau fractures.

Anatomic reduction of articular depression tibial plateau fractures is challenging. The authors describe a new technique using percutaneous balloon-guided inflation osteoplasty for a depressed lateral tibial plateau fracture. The fluoroscopy-guided inflation osteoplasty restores the joint surface anatomically in a minimally invasive fashion. The metaphyseal void is filled with a fast-setting fluid-phase bone substitute, and a lateral buttress plate is applied with less invasive incisions. This technique is a valid alternative for indirect reduction of depressed articular tibial plateau fractures.

Distal femoral fixation: a biomechanical comparison of retrograde nail, retrograde intramedullary nail, and prototype locking retrograde nail.

BACKGROUND: Distal femur fractures continue to be a complex surgical problem for which the incidence is increasing. Presently, there is a need for different constructs to address these complex fractures. This study attempts to define the biomechanical properties of several implants. METHODS: A novel, prototype locking retrograde intramedullary nail and the Russell-Taylor femoral retrograde nail were tested at non-destructive, physiological, axial mode load strength using a young, synthetic bone model for a medial segmental shaft defect in the supracondylar region of the distal femur (medial gap of 10mm, 65mm proximal to the distal joint and parallel to the knee axis). Each specimen was compressively loaded and unloaded to the peak load for 80,000cycles at a 0.5Hz frequency. These were compared to the results from the same lab of the retrograde Trigen intramedullary nail. Motion and peak displacement were measured across the fracture site as a reflection of construct stability. FINDINGS: Previous testing demonstrated that Trigen intramedullary nail had significantly less motion across the gap and increased overall stiffness of the construct (P<0.05) compared to both Russell-Taylor and prototype nails. INTERPRETATION: Locking technology used in a nail biomechanically appears to lead to more micro-motion across the fracture gap and to less stiffness in this construct. Further research needs to be invested into intramedullary, locking technology before introducing it into clinical practice.

Distal femoral fixation: a biomechanical comparison of trigen retrograde intramedullary (i.m.) nail, dynamic condylar screw (DCS), and locking compression plate (LCP) condylar plate.

BACKGROUND: The purpose of this study was to establish if there are biomechanical differences between implants in stiffness of construct, microdisplacement, and fatigue failure in a supracondylar femoral fracture model. METHODS: A retrograde intramedullary (i.m.) nail, dynamic condylar screw (DCS), and locked condylar plate (LCP) were tested using 33-cm long synthetic femurs. A standardized supracondylar medial segmental defect was created in the distal femur bone models. A gap away from the distal joint axis and parallel to the knee axis was created for axial testing of the specimens (Arbeitsgemeinschaft fur Osteosynthesefragen [AO] type 33-A) and a T-fracture (33-C) was created for the fatigue testing of the specimens. Peak displacements were measured, and analysis was done to determine construct stiffness and gap micromotion in axial loading. Cyclic loading was performed for fatigue testing. RESULTS: It was observed that there were statistically significant differences in micromotion across the fracture gap and overall stiffness of various implant constructs. The stiffness of the i.m. nail, DCS, and LCP were 1,106, 750, and 625 N/mm, respectively. The average total micromotion across the fracture gap for the i.m. nail, DCS, and LCP were 1.96, 10.55, and 17.74 mm, respectively. In fatigue testing, the i.m. nail distal screws failed at 9,000 cycles, the DCS did not fail (80,000 cycles completed), and the LCP failed at 19,000 and 23,500 cycles. CONCLUSIONS: When considering micromotion and construct stiffness, the i.m. nail had statistically significant higher stiffness and significantly lower micromotion across the fracture gap with axial compression. Hence, the i.m. nail tested had the greatest stability for type 33-A fractures. However, the nail demonstrated the least amount of resistance to fatigue failure with type 33-C fractures, whereas the DCS did not fail with testing in any pattern.

Impact magnitudes applied by surgeons and their importance when applying the femoral head onto the Morse taper for total hip arthroplasty.

INTRODUCTION: This study was designed to test whether the number of impacts, the experience of the surgeon or impact force made significant difference in pull off forces. MATERIALS AND METHODS: The forces applied by 10 orthopaedic surgeons (five residents and five attending staff) to impact the femoral head onto the trunnion of a femoral component were recorded. The resultant forces were then divided into four energy levels and compared to determine if the number of impacts would make a difference in pull off strength. RESULTS: No significant differences existed between the resident versus attending groups in magnitude of force applied. Through ANOVA testing, it was found that at each of the energy levels, multiple blows demonstrated a significant pull off strength difference compared to a single blow. Increased pull off force was also noted when the magnitude of force of the applied blows was increased. CONCLUSION: We recommend at least two firm, axially aligned blows to impact the femoral head onto the trunnion intra-operatively.