Alfred A. Mansour

Quantitative measures of femoral fracture repair in rats derived by micro-computed tomography

Although fracture healing is frequently studied in pre-clinical models of long bone fractures using rodents, there is a dearth of objective quantitative techniques to assess successful healing. Biomechanical testing is possibly the most quantitative and relevant to a successful clinical outcome, but it is a destructive technique providing little insight into the cellular mechanisms associated with healing. The advent of X-ray computed tomography (CT) has provided the opportunity to quantitatively and non-destructively assess bone structure and density, but it is unknown how measurements derived using this technology relate to successful healing. To examine possible relationships, we used a pre-clinical model to test for statistically significant correlations between quantitative characteristics of the callus by micro-CT (microCT) and the bending strength, stiffness, and energy-to-failure of the callus as assessed by three-point bending of excised bones. A closed, transverse fracture was generated in the mid-shaft of rat femurs by impact loading. Shortly thereafter, the rats received a one-time, local injection of either the vehicle or one of four doses of lovastatin. Following sacrifice after 4 weeks of healing, fractured femurs were extracted for microCT analysis and then three-point bending. Setting the region of interest to be 3.2 mm above and below the fracture line, we acquired standard and new microCT-derived measurements. The mineralized callus volume and the mineral density of the callus correlated positively with callus strength (rxy = -0.315, p = 0.016 and rxy = 0.444, p<0.0005, respectively) and stiffness (rxy = -0.271, p = 0.040 and rxy = 0.325, p = 0.013, respectively), but the fraction of the callus that mineralized and the moment of inertia of the callus did not. This fraction did correlate with energy-to-failure (rxy = -0.343, p = 0.0085). Of the microCT-derived measurements, quantifying defects within the outer bridging cortices of the callus produced the strongest correlation with both callus strength (rxy = 0.557, p<0.0001) and stiffness (rxy = 0.468, p = 0.0002). By both reducing structural defects and increasing mineralization, lovastatin appears to increase the callus strength.

Immediate Spica Casting of Pediatric Femoral Fractures in the Operating Room Versus the Emergency Department: Comparison of Reduction, Complications, and Hospital Charges

Background Immediate spica casting for pediatric femur fractures is well described as a standard treatment in the literature. The purpose of this study is to evaluate the application of a spica cast in the emergency department (ED) versus the operating room (OR) with regard to quality of reduction, complications, and hospital charges at an academic institution. Methods An institutional review board-approved retrospective review identified 100 children aged 6 months to 5 years between January 2003 and October 2008 with an isolated femur fracture treated with a hip spica cast. Patients were compared based on the setting of spica cast application. Results There were 79 patients in the ED cohort and 21 patients in the OR cohort. There were no significant differences in age, weight, sex, fracture pattern, prereduction shortening, injury mechanism, duration of spica treatment, time to heal, or length of follow-up between cohorts. There were no significant differences in the rate of loss of reduction requiring revision casting or operative treatment (6.3% vs. 4.8%), the need for cast wedging (8.9% vs. 14.3%), or minor skin breakdown (12.7% vs. 14.3%). There were no sedation or anesthetic complications in either group. There were no significant differences in the quality of reduction or the rate of complications between the 2 groups. Spica casting in the OR delayed the time from presentation to cast placement as compared with the ED cohort (11.5 h vs. 3.8 h, P<0.0001) and lengthened the hospital stay (30.5 h vs. 16.9 h, P=0.0002). The average hospital charges of spica cast application in the OR was 3 times higher than the cost of casting in the ED (

New Tension Band Material for Fixation of Transverse Olecranon Fractures: A Biomechanical Study

15,983 vs.

Comparison of two tension-band fixation materials and techniques in transverse patella fractures: A biomechanical study

5150, P<0.0001). Conclusions Immediate spica casting in the ED and OR provide similar results in terms of reduction and complications. With the significantly higher hospital charges for spica casting in the OR, alternative settings should be considered. Level of Evidence III—Retrospective comparative study.

Incidence of meniscal injury and chondral pathology in anterior tibial spine fractures of children.

This study tested the use of braided polyethylene cable as an option for repairing transverse olecranon fractures. Six cadaveric elbows underwent a transverse olecranon osteotomy followed by fixation with tension band constructs using 18-gauge wire and Secure-Strand (U.S. Surgical, North Haven, Conn). Distraction forces up to 450 N were applied to the triceps tendon while measuring fracture displacement with an extensometer. The average maximal fracture gap with the standard AO tension band technique using stainless steel wire was 0.66 +/- 0.43 mm, as opposed to 0.68 +/- 0.45 mm with braided polyethylene cable. A paired t test indicated no significant difference between the two materials. These results support the feasibility of braided polyethylene cable as an alternative to the standard steel-wire tension band.

Eye Protection in Orthopaedic Surgery: An in Vitro Study of Various Forms of Eye Protection and Their Effectiveness

This study compared the biomechanical properties of 2 tension-band techniques with stainless steel wire and ultra high molecular weight polyethylene (UHMWPE) cable in a patella fracture model. Transverse patella fractures were simulated in 8 cadaver knees and fixated with figure-of-8 and parallel wire configurations in combination with Kirschner wires. Identical configurations were tested with UHMWPE cable. Specimens were mounted to a testing apparatus and the quadriceps was used to extend the knees from 90 degrees to 0 degrees; 4 knees were tested under monotonic loading, and 4 knees were tested under cyclic loading. Under monotonic loading, average fracture gap was 0.50 and 0.57 mm for steel wire and UHMWPE cable, respectively, in the figure-of-8 construct compared with 0.16 and 0.04 mm, respectively, in the parallel wire construct. Under cyclic loading, average fracture gap was 1.45 and 1.66 mm for steel wire and UHMWPE cable, respectively, in the figure-of-8 construct compared with 0.45 and 0.60 mm, respectively, in the parallel wire construct. A statistically significant effect of technique was found, with the parallel wire construct performing better than the figure-of-8 construct in both loading models. There was no effect of material or interaction. In this biomechanical model, parallel wires performed better than the figure-of-8 configuration in both loading regimens, and UHMWPE cable performed similarly to 18-gauge steel wire.

Verification of Musculoskeletal FDG-PET-CT Findings Performed for Melanoma Staging

Background: Pediatric avulsion fractures of the anterior tibial spine are injuries similar to anterior cruciate ligament injuries in adults. Sparse data exists on the association between anterior tibial spine fractures (ATSFs) and injury to the meniscus or cartilage of the knee joint in children. This research presents a retrospective review of clinical records, imaging, and operative reports to characterize the incidence of concomitant injury in cases of ATSFs in children. The purpose of this study was to better delineate the incidence of associated injuries in fractures of the anterior tibial spine in the pediatric population. Methods: We identified 58 patients who sustained an ATSF and met inclusion criteria for this study between 1996 and 2011. The subjects were separated by the Myers and McKeever classification into type I, II, and III fractures, and each of these were subclassified by associated injury pattern. Results: 59% of children with an ATSF had an associated soft tissue or other bony injury diagnosed by magnetic resonance imaging or arthroscopy. The most prevalent associated injuries were meniscal entrapment, meniscal tears, and chondral injury. We found no meniscal or chondral injury associated with type I fractures. Twenty-nine percent of type II injuries demonstrated meniscal entrapment, 33% showing meniscal tears. Seven percent demonstrated chondral injury. Forty-eight percent of type III fractures had entrapment, whereas 12% showed meniscal tears. Eight percent had a chondral injury. Conclusions: A majority (59%) of displaced ATSF had either concomitant meniscal, ligamentous, or chondral injury. This finding suggests that magnetic resonance imaging evaluation is an important aspect of the evaluation of these injuries, particularly in type II and type III patterns. To date, this study reports the largest number of patients to evaluate the specific question of concomitant injuries in ATSFs in the pediatric population. Level of Evidence: Level IV.

A cadaveric simulation of distal femoral traction shows safety in magnetic resonance imaging.

BACKGROUND Conjunctival contamination from splashed debris during orthopaedic surgical procedures places surgeons at risk for communicable diseases such as human immunodeficiency virus (HIV) and hepatitis B and C. The purpose of this study was to compare the effectiveness of various types of protective eyewear in preventing conjunctival contamination. METHODS A simulation model was constructed with use of a mannequin head in a typical position of a surgeons head during an operation. The head was placed at an appropriate distance from the surgical field, and a femoral osteotomy was performed on a cadaver thigh. Six experimental groups were tested to determine the ability of various types of eye protection to prevent contamination of the conjunctiva: (1) modern prescription glasses, (2) standard surgical telescopic loupes, (3) hard plastic contoured glasses, (4) disposable plastic glasses, (5) a combination facemask and eye shield, and (6) no protection (control). Thirty femoral osteotomies were performed, and contamination of both the protective devices and the simulated conjunctival surfaces were recorded. RESULTS None of the tested devices were completely effective. The modern prescription glasses and the controls both were associated with conjunctival contamination rates of 83%. The other eye protective devices were associated with significantly lower rates of overall contamination, with a rate of 50% for the loupes, 30% for the facemask and eye shield, 17% for the hard plastic glasses, and 3% for the disposable plastic glasses. CONCLUSIONS Modern prescription glasses provided no benefit over the control in our experimental model; therefore, we do not recommend that they be used as the sole eye protection, especially during surgical procedures in which there is a high rate of debris expulsion from the wound. Readily available and disposable plastic glasses were associated with the lowest rate of conjunctival contamination (3%) and are an effective means with which to protect the orthopaedic surgeon from communicable diseases by conjunctival contamination.

Post-arthroscopic elbow chondrolysis after continuous intra-articular ropivacaine infusion

BackgroundThe purpose of this study is to establish the validity of F-18-deoxyglucose positron emission tomography–computed tomography (FDG-PET-CT) scan staging for cutaneous melanoma when a musculoskeletal image abnormality is detected.MethodsAn institutional review board (IRB)-approved prospective database was queried to identify 342 melanoma patients treated between 4/1999 and 12/2007. A total of 682 whole-body FDG-PET-CT scans performed for staging were retrospectively reviewed to identify FDG-avid lesions in the deep soft tissues/muscle, bone or joints (i.e., musculoskeletal sites). Images were correlated with follow-up patient records.ResultsThere were 187 true-positive sites on 94 scans and 26 false-positive sites on 22 scans. The overall false-positive rate was 13.9% (26/187). The positive predictive value (PPV) of an isolated musculoskeletal FDG-avid site was 31%. The PPV was highest (100%) when findings were present in both the bone and deep soft tissues. The relative risk of an isolated FDG-avid site compared with multiple FDG-avid sites not being melanoma was 5.33 [95% confidence interval (CI) 2.85–9.94]. The relative risk of an FDG-avid site seen in the appendicular region not being melanoma was 1.78 (95% CI 0.87–3.64) that of a site seen in the axial region.ConclusionsFDG-PET-CT scanning for staging and surveillance in the extremities of patients with high-risk melanoma often creates confusing clinical scenarios. Our data suggest that a select subset of patients with isolated avid appendicular musculoskeletal scan may not have metastatic melanoma.

Corticosteroid Injections Hasten Return to Play of National Football League Players Following Stable Ankle Syndesmosis Sprains

Objective: The purpose of this study was to evaluate the safety of a distal femoral traction pin subjected to a 1.5-T magnetic resonance image (MRI) with regard to pin migration and implant heating in a cadaveric model. Methods: Deflection angles of various traction pins as well as a Bohler-style Steinmann Pin Tractor Bow (tractor bow) and a Kirschner wire bow subjected to a 1.5-T clinical MRI were measured. Tractions pins were placed into a cadaveric femur and the tractor bow was attached to the most distal pin to simulate distal femoral traction. Temperature and migration were measured after subjecting the cadaveric leg to a “worst-case scenario” MRI sequence for 30 minutes. Results: All traction pins and bows showed deflection. The Kirschner wire bow showed a hazardous level of deflection and was immediately removed from further testing. The pin temperature changes were not significantly different than the changes in the MRI room temperature and a conduction loop was not seen in the combination pin and tractor bow. There was no significant migration of any pin nor was there objective loosening from pin vibration. Conclusions: Implant-quality stainless steel traction pins show no signs of adverse heating or pin migration when subjected to 1.5-T MRI clinical scanning. Kirschner bows are highly ferromagnetic and should not be used unless individually tested for safety. Steinmann Pin Tractor Bows that show weak ferromagnetism preliminarily appear safe to use during a 1.5-T MRI and do not produce a conduction loop with excessive heating in a cadaveric model, although further testing is indicated.