Daniel S. Horwitz

Cyclic Loading of Olecranon Fracture Fixation Constructs

Background: Despite the good results that are usually reported after fixation at the sites of olecranon fractures and osteotomies, problems such as loss of fixation, nonunion, and the need for revision surgery are still encountered. Various types of fixation have been recommended, but few have been evaluated with use of clinically relevant cyclic load testing at appropriate levels of stress. The purpose of the present study was to test multiple olecranon fixation techniques under physiologic cyclic loads. Methods: We studied ten cadaveric elbows with use of cyclic loading that simulated (1) active range of motion and (2) pushing up from a chair. Each specimen underwent fixation of a simulated 50% transverse olecranon fracture with use of intramedullary and cortically fixed tension band constructs (in randomized order) followed by fixation with a 7.3-mm-diameter cancellous screw with and without a tension band. Displacement transducers were placed posteriorly on the tension side and anteriorly near the articular surface. Results: Both configurations involving the 7.3-mm-diameter cancellous screw provided the most stable fixation—nearly five times better than that provided by the Kirschner-wire techniques. Use of the tension band in conjunction with the intramedullary screw improved the stability of fixation. In none of the constructs did the AO tension band result in compression across the osteotomy gap. Conclusions and Clinical Relevance: The use of a 7.3-mm screw in conjunction with a tension band provided better fixation of simulated displaced transverse fractures than did the use of Kirschner wires in conjunction with a tension band or the use of a screw only. The AO principle of converting posterior tensile forces to articular compressive forces was not demonstrated in this study. We therefore question the validity of the tension band concept in olecranon fracture fixation and recommend passive rather than active range of motion in the immediate postoperative period to limit fracture distraction.

Results of polyaxial locked-plate fixation of periarticular fractures of the knee

BACKGROUND Locked-plate fracture-fixation techniques and designs continue to evolve. Polyaxial locking plates that allow screw angulation and end-point locking have become available; however, there are no clinical data documenting their strength and efficacy, to our knowledge. The purpose of this study was to evaluate the clinical performance of a variable-axis locking plate in a multicenter series of periarticular fractures about the knee. METHODS Between 2003 and 2005, fifty-four patients with a total of fifty-six fractures were treated with a polyaxial locked-plate fixation system (DePuy, Warsaw, Indiana). There were twenty male patients and thirty-four female patients with a mean age of fifty-seven years. There were twenty-five distal femoral fractures and thirty-one proximal tibial fractures. Twelve of the fractures were open. Clinical and radiographic data, including changes in alignment, hardware breakage, or other mechanical complications of the device, were retrospectively reviewed. Function was assessed with use of the Knee Society scores. One patient with a bilateral fracture died less than three months postoperatively, and two patients were lost to follow-up prior to union. Fifty-two fractures in fifty-one patients were followed to union or for a minimum of six months; the mean duration of follow-up was nine months (range, six to twenty-five months). RESULTS Forty-nine (94%) of the fifty-two fractures united. There were no mechanical complications. Most importantly, there was no evidence of varus collapse as a result of polyaxial screw failure. There were three deep infections and one aseptic nonunion. No plate fractured, and no screw cut out. CONCLUSIONS The variable-axis locking plates performed well, with a high rate of fracture union and no evidence of varus collapse due to failure of the polyaxial screw fixation, in a series of complex fractures about the knee. Complication rates were similar to those for historical controls treated with fixed-trajectory locking plates. Polyaxial locking plates offer more fixation versatility without an apparent increase in mechanical complications or loss of reduction.

A biomechanical analysis of internal fixation of complex tibial plateau fractures.

OBJECTIVE To compare the mechanical stability of fixation of an unstable bicondylar tibial plateau fracture with several different fixation techniques in a cadaveric model. DESIGN Randomized laboratory investigation using a simulated bicondylar tibial plateau fracture with metaphyseal-diaphyseal dissociation. SETTING Complex tibial plateau fractures were instrumented and tested under ramp and cyclic loading conditions on a servohydraulic materials testing machine. INTERVENTION Each tibia was instrumented sequentially with a lateral buttress plate, a lateral and a medial buttress plate, and a lateral buttress and an anteromedial antiglide plate for ramp load testing. For cyclic testing, one of the three constructs was used on each specimen. MAIN OUTCOME MEASUREMENTS Vertical subsidence of the medial tibial plateau was measured in both ramp and cyclic loading in order to evaluate the three internal fixation techniques. RESULTS No significant difference was measurable between the dual buttress construct and the lateral buttress/anteromedial antiglide construct. However, the lateral buttress plate alone provided significantly less stability. CONCLUSIONS A lateral buttress plate with an anteromedial antiglide plate may provide equally effective fixation as compared with the dual buttress plating technique in complex tibial plateau fractures. This less invasive technique may also be associated with fewer complications due to the lack of soft tissue stripping that is required for its application.

Increased traffic accident rates associated with shale gas drilling in Pennsylvania.

OBJECTIVES We examined the association between shale gas drilling and motor vehicle accident rates in Pennsylvania. METHODS Using publicly available data on all reported vehicle crashes in Pennsylvania, we compared accident rates in counties with and without shale gas drilling, in periods with and without intermittent drilling (using data from 2005 to 2012). Counties with drilling were matched to non-drilling counties with similar population and traffic in the pre-drilling period. RESULTS Heavily drilled counties in the north experienced 15-23% higher vehicle crash rates in 2010-2012 and 61-65% higher heavy truck crash rates in 2011-2012 than control counties. We estimated 5-23% increases in crash rates when comparing months with drilling and months without, but did not find significant effects on fatalities and major injury crashes. Heavily drilled counties in the southwest showed 45-47% higher rates of fatal and major injury crashes in 2012 than control counties, but monthly comparisons of drilling activity showed no significant differences associated with drilling. CONCLUSIONS Vehicle accidents have measurably increased in conjunction with shale gas drilling.

Treatment of pertrochanteric fractures (OTA 31-A1 and A2): long versus short cephalomedullary nailing.

Objectives: To retrospectively compare the clinical outcomes in patients with pertrochanteric femur fractures without subtrochanteric extension (OTA 31-A1 and A2) after treatment with short or long cephalomedullary nails. Design: Retrospective study. Setting: Academic level I trauma center. Patients: Two hundred eighty three adult patients presenting with simple or multifragmentary pertrochanteric femur fractures (OTA 31-A1 and A2) between 2004 and 2009 qualified for inclusion in this study. Intervention: One hundred patients were treated with a short cephalomedullary nail and 183 with a long cephalomedullary nail. Main Outcome Measurements: Patient demographics and medical comorbidities were recorded for each patient via an electronic medical record. Treatment-related variables including the American Society of Anesthesiologists (ASA) score, duration of surgery, volume of intraoperative blood loss, need for blood products, treatment-related complications, and mortality were recorded and compared between the short and long nail groups. Results: There were no significant difference between treatment modalities, complication, and reoperation rates for the 2 groups. Treatment with a long nail resulted in subtle increases in procedure time and blood loss. Conclusions: No differences in the union and complication rates between the 2 groups were identified, suggesting that long nails offer no advantage compared with short nails for stabilizing simple and multifragmentary pertrochanteric femur fractures without subtrochanteric extension (OTA 31-A1 and A2). Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Determination of Radiographic Healing: An Assessment of Consistency Using RUST and Modified RUST in Metadiaphyseal Fractures.

Objective: To determine the reliability of the Radiographic Union Scale for Tibia (RUST) score and a new modified RUST score in quantifying healing and to define a value for radiographic union in a large series of metadiaphyseal fractures treated with plates or intramedullary nails. Design: Healing was evaluated using 2 methods: (1) evaluation of interrater agreement in a series of radiographs and (2) analysis of prospectively gathered data from 2 previous large multicenter trials to define thresholds for radiographic union. Intervention: Part 1: 12 orthopedic trauma surgeons evaluated a series of radiographs of 27 distal femur fractures treated with either plate or retrograde nail fixation at various stages of healing in random order using a modified RUST score. For each radiographic set, the reviewer indicated if the fracture was radiographically healed. Part 2: The radiographic results of 2 multicenter randomized trials comparing plate versus nail fixation of 81 distal femur and 46 proximal tibia fractures were reviewed. Orthopaedic surgeons at 24 trauma centers scored radiographs at 3, 6, and 12 months postoperatively using the modified RUST score above. Additionally, investigators indicated if the fracture was healed or not healed. Main Outcome Measures: The intraclass correlation coefficient (ICC) with 95% confidence intervals was determined for each cortex, the standard and modified RUST score, and the assignment of union for part 1 data. The RUST and modified RUST that defined “union” were determined for both parts of the study. Results: ICC: The modified RUST score demonstrated slightly higher ICCs than the standard RUST (0.68 vs. 0.63). Nails had substantial agreement, whereas plates had moderate agreement using both modified and standard RUST (0.74 and 0.67 vs. 0.59 and 0.53). Union: The average standard and modified RUST at union among all fractures was 8.5 and 11.4. Nails had higher standard and modified RUST scores than plates at union. The ICC for union was 0.53 (nails: 0.58; plates: 0.51), which indicates moderate agreement. However, the majority of reviewers assigned union for a standard RUST of 9 and a modified RUST of 11, and >90% considered a score of 10 on the RUST and 13 on the modified RUST united. Conclusions: The ICC for the modified RUST is slightly higher than the standard RUST in metadiaphyseal fractures and had substantial agreement. The ICC for the assessment of union was moderate agreement; however, definite union would be 10 and 13 with over 90% of reviewers assigning union. These are the first data-driven estimates of radiographic union for these scores.

Results of Polyaxial Locked-Plate Fixation of Periarticular Fractures of the Knee: Surgical Technique

BACKGROUND Locked-plate fracture-fixation techniques and designs continue to evolve. Polyaxial locking plates that allow screw angulation and end-point locking have become available; however, there are no clinical data documenting their strength and efficacy, to our knowledge. The purpose of this study was to evaluate the clinical performance of a variable-axis locking plate in a multicenter series of periarticular fractures about the knee. METHODS Between 2003 and 2005, fifty-four patients with a total of fifty-six fractures were treated with a polyaxial locked-plate fixation system (DePuy, Warsaw, Indiana). There were twenty male patients and thirty-four female patients with a mean age of fifty-seven years. There were twenty-five distal femoral fractures and thirty-one proximal tibial fractures. Twelve of the fractures were open. Clinical and radiographic data, including changes in alignment, hardware breakage, or other mechanical complications of the device, were retrospectively reviewed. Function was assessed with use of the Knee Society scores. One patient with a bilateral fracture died less than three months postoperatively, and two patients were lost to follow-up prior to union. Fifty-two fractures in fifty-one patients were followed to union or for a minimum of six months; the mean duration of follow-up was nine months (range, six to twenty-five months). RESULTS Forty-nine (94%) of the fifty-two fractures united. There were no mechanical complications. Most importantly, there was no evidence of varus collapse as a result of polyaxial screw failure. There were three deep infections and one aseptic nonunion. No plate fractured, and no screw cut out. CONCLUSIONS The variable-axis locking plates performed well, with a high rate of fracture union and no evidence of varus collapse due to failure of the polyaxial screw fixation, in a series of complex fractures about the knee. Complication rates were similar to those for historical controls treated with fixed-trajectory locking plates. Polyaxial locking plates offer more fixation versatility without an apparent increase in mechanical complications or loss of reduction.

Techniques for the Surgical Treatment of Distal Tibia Fractures

Surgical management of extra-articular distal tibia fractures has evolved because of the high rate of complications with conventional techniques and the technically challenging aspects of the surgery. Open reduction and internal fixation with plating or nailing remain the gold standards of treatment, and minimally invasive techniques have reduced wound complications and increased healing. Adequate reduction and stabilization as well as appropriate soft tissue management are imperative to achieving good outcomes in these fractures.

The Economic Impact of Reprocessing External Fixation Components

BACKGROUND The trend toward temporizing external fixation of complex fractures has resulted in increased expenditures for these devices. Increasing pressure to reduce health-care expenditures has led to exploration of reuse of equipment intended for single use. Devices must be tested and recertified prior to redeployment in hospital stock. We report the rate of manufacturer recertification and institutional cost savings associated with a reuse program approved by the United States Food and Drug Administration. METHODS All Hoffmann-II external fixation components that had been removed at our institution during the study period were submitted to the manufacturer for visual inspection and mechanical testing. Pass rates for original components and previously recycled components were determined. With use of a conservative pass rate and the assumption of a maximum of three recertifications of each component, the total potential hospital savings on external fixation were calculated. RESULTS The first pass rate was 76%. The second pass rate (i.e., the rate for components that had already been recertified once and had been sent for a second recertification) was 83%, but that rate was derived from a limited sample. On the basis of a conservative pass-rate estimate of 75%, the predicted average number of uses of a recyclable component was 2.7. The recertified components were sold back to our hospital at 50% of the original price. Because carbon-fiber bars and half-pins are not recycled, 85% of the charges expended on a new external fixation component are spent on portions of the system that are recyclable. The potential total savings on reusable components was found to be 32%, with a total savings of 27% for the whole external fixation system. No recertified components failed in clinical use over the course of the study. CONCLUSIONS With the expansion of cost-control efforts, the recycling of medical devices appears inevitable. Previous data have demonstrated the safety of reuse of external fixation devices, and this study confirms that finding. Our paper demonstrates the real cost savings associated with a manufacturer-based testing and recertification program. Issues of voluntary participation in reuse programs, component ownership, and the impact of savings on patient charges are yet to be worked out by individual institutions.

Healing Time and Complications in Operatively Treated Atypical Femur Fractures Associated With Bisphosphonate Use: A Multicenter Retrospective Cohort

Objectives: The purpose of this study was to characterize demographics, healing time, and complications of a large series of operatively treated atypical femur fractures. Design: Retrospective multicenter review. Setting: Seventeen academic medical centers. Patients: Bisphosphonate-related fractures as defined by American Society of Bone and Mineral Research. Fractures had to be followed for at least 6 months or to union or revision. Intervention: Operative treatment of bisphosphonate-related fracture. Main Outcome Measurements: Union time and complications of treatment, as well as information about the contralateral limb. Results: There were 179 patients, average age 72, average body mass index 27.2. Average follow-up was 17 months. Twenty-one percent had a previous history of fragility fracture; 34% had prodromal pain. Most (88%) lived independently before injury. Thirty-one percent had radiographic changes suggesting stress reaction. Surgical fixation was with cephalomedullary nail (51%), IM nail (48%), or plate (1%). Complications included death (4), PE (3), and wound infection (6). Twenty (12%) patients underwent revision at an average of 11 months. Excluding revisions, average union time was 5.2 months. For revisions, union occurred at an average of 10.2 months after intervention. No association was identified between discontinuation of bisphosphonates and union time (P = 0.5) or need for revision (P = 0.7). Twenty-one percent sustained contralateral femur fractures; 32% of these had pain and 59% had stress reaction before contralateral fracture. Conclusions: In this series, surgery had a 12% failure rate and delayed average time to union. Twenty-one percent developed contralateral femur fractures within 2 years, underscoring the need to evaluate the contralateral extremity. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.