Comparing a Portable Motion Analysis System against the Gold Standard for Potential Anterior Cruciate Ligament Injury Prevention and Screening.

Knee kinematics during a drop vertical jump, measured by the Kinect V2 (Microsoft, Redmond, WA, USA), have been shown to be associated with an increased risk of non-contact anterior cruciate ligament injury. The accuracy and reliability of the Microsoft Kinect V2 has yet to be assessed specifically for tracking the coronal and sagittal knee angles of the drop vertical jump. Eleven participants performed three drop vertical jumps that were recorded using both the Kinect V2 and a gold standard motion analysis system (Vicon, Los Angeles, CA, USA). The initial coronal, peak coronal, and peak sagittal angles of the left and right knees were measured by both systems simultaneously. Analysis of the data obtained by the Kinect V2 was performed by our software. The differences in the mean knee angles measured by the Kinect V2 and the Vicon system were non-significant for all parameters except for the peak sagittal angle of the right leg with a difference of 7.74 degrees and a p-value of 0.008. There was excellent agreement between the Kinect V2 and the Vicon system, with intraclass correlation coefficients consistently over 0.75 for all knee angles measured. Visual analysis revealed a moderate frame-to-frame variability for coronal angles measured by the Kinect V2. The Kinect V2 can be used to capture knee coronal and sagittal angles with sufficient accuracy during a drop vertical jump, suggesting that a Kinect-based portable motion analysis system is suitable to screen individuals for the risk of non-contact anterior cruciate ligament injury.

Evaluating femoral graft placement using three-dimensional magnetic resonance imaging in the reconstruction of the anterior cruciate ligament via independent or transtibial drilling techniques: a retrospective cohort study.

PURPOSE: Anterior cruciate ligament (ACL) reconstruction is a common surgical procedure, yet failure still largely occurs due to nonanatomically positioned grafts. The purpose of this study was to retrospectively evaluate patients with torn ACLs before and after reconstruction via 3D MRI and thereby assess the accuracy of graft position on the femoral condyle. METHODS: Forty-one patients with unilateral ACL tears were recruited. Each patient underwent 3D MRI of both knees before and after surgery. The location of the reconstructed femoral footprint relative to the patient's native footprint was compared. RESULTS: Native ACL anatomical location of the native ACL had a significant impact on graft position. Native ACLs that were previously more anterior yielded grafts that were more posterior (3.70 ± 1.22 mm, P = 0.00018), and native ACL that were previously more proximal yielded grafts that were more distal (3.25 ± 1.09 mm, P = 0.0042). Surgeons using an independent drilling method positioned 76.2% posteriorly relative to the native location, with a mean 0.1 ± 2.8 mm proximal (P = 0.8362) and 1.8 ± 3.0 mm posterior (P = 0.0165). Surgeons using a transtibial method positioned 75% proximal relative to the native location, with a mean 2.2 ± 3.0 mm proximal (P = 0.0042) and 0.2 ± 2.6 mm posterior (P = 0.8007). These two techniques showed a significant difference in magnitude in the distal-proximal axis (P = 0.0332). CONCLUSION: The femoral footprint position differed between the native and reconstructed ACLs, suggesting that ACL reconstructions are not accurate. Rather, they are converging to a normative reference point that is neither anatomical nor isometric.

Enhanced Bone Remodeling After Fracture Priming.

The immune system is an active component of bone repair. Mast cells influence the recruitment of macrophages, osteoclasts and blood vessels into the repair tissue. We hypothesized that if mast cells and other immune cells are sensitized to recognize broken bone, they will mount an increased response to subsequent fractures that may be translated into enhanced healing. To test this, we created a bone defect on the left leg of anesthetized mice and 2 weeks later, a second one on the right leg. Bone repair in the right legs was then compared to control mice that underwent the creation of bilateral window bone defects at the same time. Mice were euthanized at 14 and 56 days. Mineralized tissue quantity and morphometric parameters were assessed using micro-CT and histology. The activity of osteoblasts, osteoclasts, vascular endothelial cells, mast cells, and macrophages was evaluated using histochemistry. Our main findings were (1) no significant differences in the amount of bone produced at 14- or 56 days post-operative between groups; (2) mice exposed to subsequent fractures showed significantly better bone morphometric parameters after 56 days post-operative; and (3) significant increases in the content of blood vessels, osteoclasts, and the number of macrophages in the subsequent fracture group. Our results provide strong evidence that a transient increase in the inflammatory state of a healing injury promotes faster bone remodelling and increased neo-angiogenesis. This phenomenon is also characterized by changes in mast cell and macrophage content that translate into more active recruitment of mesenchymal stromal cells.

Augmented-reality-guided insertion of sliding hip screw guidewire: a preclinical investigation.

BACKGROUND: The sliding hip screw (SHS) is frequently used in the management of hip fractures; successful placement depends on accurate positioning of the lag screw in the femoral head guided by fluoroscopy. We proposed to leverage the capabilities of augmented reality (AR) to overlay virtual images of the desired guidewire trajectory directly onto the surgical field to guide the surgeon during SHS guidewire insertion. METHODS: Using a commercially available AR headset and software, we performed preprocedural planning using computed tomography scans to identify the optimal trajectory for SHS guidewire insertion in the neck of a Sawbones femur model. The images of the scanned femurs containing the virtual guidewire trajectory were overlaid on the physical models such that the user could see a composite view of the computer-generated images and the physical environment. Two second-year orthopedic residents each inserted 15 guidewires under AR guidance and 15 guidewires under fluoroscopy. RESULTS: Of the 30 guidewires inserted under AR guidance, 24 (80%) were within the femoral neck, and 16 (53%) were fully enclosed within the femoral head. Nine (56%) of the 16 perforations were due to insertions that were too far along the planned trajectory. Thirteen (81%) of the successful attempts with AR had an appropriate position, compared to 25/26 (96%) with fluoroscopy. It took significantly less time to perform the procedure using fluoroscopy than AR (p < 0.05). Fluoroscopy required on average 18.7 shots. CONCLUSION: Augmented reality provides an opportunity to aid in guidewire insertion in a preplanned trajectory with less radiation exposure in a sterile environment, but technical challenges remain to be solved to enable widespread adoption.

Defective bone repair in diclofenac treated C57Bl6 mice with and without lipopolysaccharide induced systemic inflammation.

Bone repair after trauma or surgical intervention involves a tightly regulated cascade of events that starts with hemostasis and an inflammatory response, which are critical for successful healing. Nonsteroidal anti-inflammatory drugs (NSAID) are routinely prescribed for pain relief despite their potential inhibitory effect on bone repair. The goal of this study was to determine the impact of administration of the non-selective NSAID diclofenac in the inflammatory phase of bone repair in mice with or without lipopolysaccharide-induced systemic inflammation. Repair of femoral window defects was characterized using micro computed tomography imaging and histological analyses at 2 weeks postoperative. The data indicate (a) impaired bone regeneration associated with reduced osteoblast, osteoclast, and macrophage activity; (b) changes in the number, activity, and distribution of mast cells in regenerating bone; and (c) impaired angiogenesis due to a direct toxic effect of diclofenac on vascular endothelial cells. The results of this study provide strong evidence to support the conjecture that administration of NSAIDs in the first 2 weeks after orthopaedic surgery disrupts the healing cascade and exacerbates the negative effects of systemic inflammation on the repair process.

Anterolateral Ligament Injury in Knee Dislocations.

PURPOSE: The purpose of this study is to describe the prevalence and associated factors of anterolateral ligament (ALL) injury in knee dislocation (KD). METHODS: A retrospective review of charts and radiological images was done for patients who underwent multiligamentous knee reconstruction surgery for KD in the authors' institution from May 2008 to December 2016. The inclusion criteria were both genders, skeletally mature, and first dislocation. Previous anterior cruciate ligament injury or surgery were the exclusion criteria. Magnetic resonance imaging was used to describe the ALL injury. The association of ALL injury with other variables related to the injury and the patient's background features was examined. RESULTS: Forty-eight patients (49 knees) were included. The mean age of the patients was 32.3 ± 10.6 years. High-energy trauma was the mechanism of dislocation in 28 (57.1%) knees. Thirty-one knees (63.3%) were classified as KD type IV. Forty-five (91.8%) knees had a complete ALL injury, and 3 (6.1%) knees had incomplete ALL injury. Forty (81.6%) knees had a complete ALL injury at the proximal fibers of the ALL, while 23 (46.9%) knees had complete distal ALL injury. None of the 46 (93.9%) knees with lateral collateral ligament injury had normal proximal ALL fibers (P = .012). Injury to the distal fibers of the ALL, as well as overall ALL injury, was not associated with any other variables (P > .05). Moreover, all patients with associated tibial plateau fractures (9; 18.4%) had abnormality of the proximal fibers of the ALL (P = .033). CONCLUSIONS: ALL injury is highly prevalent among dislocated knees. Most of the injuries are of high grade and involve the proximal, suprameniscal, fibers of the ligament. LEVEL OF EVIDENCE: Level IV, retrospective case series with no comparison group.

"Hockey wrist:" dorsal ulnotriquetral ligament injury.

BACKGROUND: Ulnar-sided wrist pain at the dorsal proximal triquetrum, especially during wrist pronation, flexion and radial deviation, is common in athletes, particularly ice hockey players. The purpose of this study was to evaluate in which position the dorsal ulnotriquetral ligament (DUTL) is placed under the greatest strain, the torque to failure and the injury pattern. We hypothesized that the DUTL is maximally strained with wrist flexion, pronation and radial deviation, and that, at failure, the ligament tears off the triquetrum. METHODS: We performed a biomechanical study on 7 fresh frozen cadaveric upper extremities, with testing done on a wrist-movement stimulator to identify the position (45° of wrist flexion, 45° of wrist extension or neutral) that generated the highest and earliest strain increases in the DUTL. We performed load-to-failure testing, characterized the ligament's pattern of failure, and repaired and retested the DUTL using the same load-to-failure protocol. RESULTS: The DUTL reached 3 N∙m the earliest in 45° of wrist flexion (p = 0.02). The native DUTL failed at 0.35 N∙m (standard deviation [SD] 0.13 N∙m) per degree of angular stiffness, 12.93 N∙m of yield strength and with angular deformation of 57.73° (SD 20.62°). There was no significant difference in these variables between the native and repaired DUTL. Tearing occurred at a mean of 10 mm (SD 2 mm) proximal from the triquetrum's insertion in a transverse midsubstance pattern. CONCLUSION: This study showed a reproducible pattern of injury to the DUTL in a cadaveric model. Additional work is needed to further characterize the pathoanatomy of "hockey wrist."

CONTEXTE: La douleur cubitale au poignet, au niveau du triquetrum proximal dorsal, surtout à la pronation, à la flexion et à la déviation radiale du poignet, est fréquente chez les athlètes, particulièrement chez les joueurs de hockey. Le but de cette étude était d'évaluer la position dans laquelle le ligament ulnotriquétral dorsal (LUTD) est soumis à la pression la plus grande, le couple de torsion menant à la défaillance et le mode de blessure. Selon notre hypothèse, le LUTD est soumis au maximum de pression lorsque le poignet est en flexion, pronation et déviation radiale, et au moment de la défaillance, le ligament ulnotriquétral se déchire. MÉTHODES: Nous avons procédé à une étude biomécanique sur 7 membres supérieurs de cadavres frais congelés, et effectué des tests sur un stimulateur de mouvements du poignet pour établir la position (flexion du poignet à 45°, extension du poignet de 45° ou position neutre) générant les augmentations de pression les plus fortes et les plus rapides sur le LUTD. Nous avons procédé à des tests de mise en charge jusqu'à défaillance, caractérisé le mode de défaillance du ligament et réparé et retesté le LUTD à l'aide du même protocole de mise en charge jusqu'à défaillance. RÉSULTATS: Le LUTD a atteint 3 N∙m le plus rapidement avec une flexion du poignet à 45° (p = 0,02). Le LUTD natif a connu une défaillance à 0,35 N∙m (écart-type [É.-T.] 0,13 N∙m) par degré de raideur angulaire, 12,93 N∙m d'élasticité et avec une déformation angulaire de 57,73° (É.-T. 20,62°). On n'a noté aucune différence significative de ces variables entre les LUTD natifs et réparés. La déchirure s'est produite en moyenne à 10 mm (É.-T. 2 mm) en proximal par rapport à l'insertion du triquetrum selon un trajet transverse affectant la moitié de la substance ligamentaire. CONCLUSION: L'étude a démontré un mode reproductible de lésion du LUTD à l'aide d'un modèle cadavérique. Il faudra approfondir la recherche pour caractériser avec plus de précision l'anatomopathologie de la lésion au poignet typiquement causée par la pratique du hockey.

A Case Report of Traumatic Partial Extensor Carpi Ulnaris Subluxation in an Elite Hockey Player With Review of the Literature.

In this article, we present a unique case of traumatic partial recurrent extensor carpi ulnaris (ECU) subluxation in an elite hockey player. To the best of our knowledge, this is the only report of partial ECU subluxation due to a split in the ECU tendon presented in the literature. This case illustrates the importance of proper diagnosis and treatment of such a lesion. We also emphasize that dynamic ultrasound is an excellent and cost-effective imaging modality that can help with the diagnosis of partial ECU subluxation. Finally, surgical treatment for failed conservative management showed excellent results in an elite athlete.

Proximal tibial fracture following anterior cruciate ligament reconstruction surgery: a biomechanical analysis of the tibial tunnel as a stress riser.

PURPOSE: This is the first biomechanical study to examine the potential stress riser effect of the tibial tunnel or tunnels after ACL reconstruction surgery. In keeping with literature, the primary hypothesis tested in this study was that the tibial tunnel acts as a stress riser for fracture propagation. Secondary hypotheses were that the stress riser effect increases with the size of the tunnel (8 vs. 10 mm), the orientation of the tunnel [standard (STT) vs. modified transtibial (MTT)], and with the number of tunnels (1 vs. 2). METHODS: Tibial tunnels simulating both single bundle hamstring graft (8 mm) and bone-patellar tendon-bone graft (10 mm) either STT or MTT position, as well as tunnels simulating double bundle (DB) ACL reconstruction (7, 6 mm), were drilled in fourth-generation saw bones. These five experimental groups and a control group consisting of native saw bones without tunnels were loaded to failure on a Materials Testing System to simulate tibial plateau fracture. RESULTS: There were no statistically significant differences in peak load to failure between any of the groups, including the control group. The fracture occurred through the tibial tunnel in 100 % of the MTT tunnels (8 and 10 mm) and 80 % of the DB tunnels specimens; however, the fractures never (0 %) occurred through the tibial tunnel of the standard tunnels (8 or 10 mm) (P = 0.032). CONCLUSIONS: In the biomechanical model, the tibial tunnel does not appear to be a stress riser for fracture propagation, despite suggestions to the contrary in the literature. Use of a standard, more vertical tunnel decreases the risk of ACL graft compromise in the event of a fracture. This may help to inform surgical decision making on ACL reconstruction technique.

Complete tear of the distal hamstring tendons in a professional football player: a case report and review of the literature.

Semimembranosus tendon ruptures are rare and are often associated with involvement of the cruciate ligaments. We present a 24-year-old American football player who sustained a complete rupture of the semimembranosus tendon near its insertion associated with an avulsion fracture of the conjoint attachment of the lateral collateral ligament (LCL) and biceps femoris with intact cruciate ligaments and menisci during practice. At the scene he was immobilized and was taken to the hospital immediately. The diagnosis was reached after radiographs and an MRI of the affected knee were obtained. The semimembranosus tendon and the avulsion of the biceps femoris insertion were repaired surgically. We also review the literature for previously reported cases of distal hamstring injuries.

The Apex of the Deep Cartilage: A Landmark and New Technique to Help Identify Femoral Tunnel Placement in Anterior Cruciate Ligament Reconstruction.

PURPOSE: The purpose of this study was to evaluate the apex of the deep cartilage (ADC) as a landmark to help guide femoral tunnel placement during anatomic single-bundle anterior cruciate ligament (ACL) reconstruction. Our secondary purpose was to assess whether or not the endoscopic transtibial femoral offset drill guide could reach the center of the ACL's femoral footprint. METHODS: Eight formalin-injected cadaveric knees were dissected and the center of the ACL femoral footprints identified. The ADC was selected as an easily identifiable landmark during arthroscopy and was used to reference the position of the ACL femoral footprint with the knee flexed at 90°. Next, a 7-mm transtibial femoral ACL drill guide was used to engage the posterior aspect of the lateral condyle at the level of the femoral footprint. This position was marked, and the distance from the center of the femoral footprint was recorded for each specimen. Descriptive statistics were used to report our measurements. RESULTS: The median high and shallow measurements were 3 mm (range, 1 to 4 mm) and 12 mm (range, 11 to 17 mm), respectively. The femoral offset guide never reached the center of the femoral footprint in all specimens; the median distance between the 2 measurements was 4.5 mm (range, 2 to 9 mm). CONCLUSIONS: If the anatomy is difficult to delineate at the time of reconstruction, our study suggests using the ADC as a landmark to guide anatomic placement. The dissection of 8 cadavers showed that the center of the ACL femoral footprint had a median position of 3 mm high and 12 mm shallow to the ADC. We also showed that the transtibial femoral offset guide did not reach the center of the ACL footprint on all specimens and should therefore not be used for anatomic ACL reconstruction. CLINICAL RELEVANCE: Current commercially available transtibial femoral offset guides cannot reach the center of the ACL's femoral footprint and therefore should not be used. Alternative techniques, such as referencing from the ADC through an anteromedial (AM) portal, are recommended.

A cadaveric analysis of tunnel position created using flexible versus rigid instrumentation in a single-incision distal biceps tendon repair.

PURPOSE: This study was designed to determine whether the use of a flexible guide pin and reamer through an anterior single-incision approach would allow for a more anatomic insertion point on the radial tuberosity when compared with the traditional rigid instrumentation used for cortical button fixation. METHODS: Seven matched pairs of fresh-frozen cadaveric upper extremity specimens were used in this study. One specimen from each matched pair was randomly assigned to undergo a simulated repair using the standard instrumentation required for a cortical button fixation device, and the other specimens were assigned to undergo the same repair using a 42° anterior cruciate ligament femoral guide with a flexible guide pin and reamer. Each specimen from both groups was positioned with the elbow in 90° of flexion and the forearm maximally supinated during guide pin insertion. The proximal portion of the radius was then harvested from the specimen and scanned using micro-computed tomography (micro-CT). Tunnel position between the 2 techniques was compared with the center of the native tendon footprint. RESULTS: The mean percentage of the reamed entry hole within the tendon footprint was significantly less using rigid instrumentation (36.35%) compared with flexible instrumentation (67.29%) (P = .043). Furthermore, when flexible reamers were used (mean offset ratio, 0.17), the resultant tunnel was positioned in a significantly more central position within the radial shaft (i.e., the offset ratio was lower) compared with rigid reamers (mean offset ratio, 0.35) (P = .043). The entry hole was found to be significantly more posterior relative to the center of the anatomic footprint for the flexible reamer group (mean, 0.21 mm anterior) compared with the rigid reamer group (mean, 3.22 mm anterior) (P = .028). There was no difference in tunnel length between the 2 groups. CONCLUSIONS: The use of a flexible guide pin and reamer allows for a more anatomically positioned repair than does rigid instrumentation through a single-incision approach. CLINICAL RELEVANCE: This surgical technique allows for a more anatomic re-creation of the distal biceps tendon insertion while maintaining the benefits of a single limited anterior exposure.

Is the clock face an accurate, precise, and reliable measuring tool for anterior cruciate ligament reconstruction?

PURPOSE: (1) To assess the use and practice of the clock face among surgeons who routinely perform anterior cruciate ligament (ACL) reconstructions, and (2) to assess the accuracy, precision, and reliability of 3 commonly used clock-face schemes in ACL reconstruction. METHODS: First, 9 surgeons completed a questionnaire assessing the use and definition of the clock-face technique. Next, to assess the accuracy, precision, and reliability of the clock face, each surgeon estimated the "time" of 8 artificial femur models with a black dot located on the posterior aspect of the lateral condylar wall. The estimates were performed using 3 different clock-face schemes and were repeated 10 months later. Solutions for each specimen were obtained by use of a computer graphical interface. RESULTS: More than half of the respondents (55%) use the clock face in ACL reconstructions, with the reported mean ideal "time" for a femoral tunnel in a right knee of 10:05 (SD, 31 minutes). When we accounted for the different clock definitions, this ideal position was found along the entire lateral condylar wall. In the assessment of the performance of the clock face, the mean error was 32 to 40 minutes (which translates to 3 to 4 mm) among the 3 clock schemes. The maximum error was 4 hours 0 minutes, and the range of responses was 1 hour 0 minutes to 4 hours 0 minutes depending on the specimen and clock scheme. Regardless of the clock scheme used, the intrarater and inter-rater reliabilities were similar-measuring, on average, 0.78 and 0.68, respectively. CONCLUSIONS: The clock face continues to be commonly used in ACL reconstruction. Different clock-face definitions affect the position for the same "time." When the clock-face parameters were strictly defined, there was good reliability with borderline accuracy and poor precision. CLINICAL RELEVANCE: Considering the borderline performance of the clock face in accuracy and poor precision, we recommend against using the clock face in ACL reconstruction.

Comparing novel smartphone pose estimation frameworks with the Kinect V2 for knee tracking during athletic stress tests.

PURPOSE: To compare the accuracy of the Microsoft Kinect V2 with novel pose estimation frameworks, in assessing knee kinematics during athletic stress tests, for fast and portable risk assessment of anterior cruciate ligament (ACL) injury. METHODS: We captured 254 varsity athletes, using the Kinect V2 and a smartphone application utilizing Google's MediaPipe framework. The devices were placed as close as possible and used to capture a person, facing the cameras, performing one of three athletic stress tests at a distance of 2.5 ms. Custom software translated the results from both frameworks to the same format. We then extracted relevant knee angles at key moments of the jump and compared them, using the Kinect V2 as the ground truth. RESULTS: The results show relatively small angle differences between the two solutions in the coronal plane and moderate angle differences on the sagittal plane. Overall, the MediaPipe framework results seem to underestimate both knee valgus angles and knee sagittal angles compared to the Kinect V2. CONCLUSION: This preliminary study demonstrates the potential for Google's MediaPipe framework to be used for calculating lower limb kinematics during athletic stress test motions, which can run on most modern smartphones, as it produces similar results to the Kinect V2. A smartphone application similar to the one developed could potentially be used for low cost and widespread ACL injury prevention.

Sonography as a tool for identifying engaging Hill-Sachs lesions: preliminary experience.

Engaging Hill-Sachs lesions can be a factor predictive of recurrent anterior shoulder instability, yet no method has been recognized as an effective means to predict engagement. We evaluated the ability of sonography to identify engaging Hill-Sachs lesions by using a transaxillary approach and dynamic scanning. In patients with engaging lesions, there was an abrupt change in the contour of the humeral head when the shoulder was in 90° of abduction and 90° of external rotation. Sonography therefore has the potential to be a useful preoperative tool in determining which patients may benefit from a surgical repair that also addresses Hill-Sachs lesions.

Risk of glove perforation with arthroscopic knot tying using different surgical gloves and high-tensile strength sutures.

PURPOSE: To examine the risk of glove tears associated with arthroscopic knot tying using 4 commonly used high-tensile strength sutures and 2 different types of gloves. METHODS: We analyzed 2 different surgical latex glove types (0.24-mm-thick powder-free and 0.32-mm-thick powdered) for perforation after arthroscopic knot tying with 4 different high-tensile strength sutures: Hi-Fi (ConMed Linvatec, Largo, FL), Ultrabraid (Smith & Nephew, Memphis, TN), FiberWire (Arthrex, Naples, FL), and Orthocord (DePuy Mitek, Raynham, MA). All knots were tied by a double-gloved single surgeon. Twelve trials of 4 knots each were performed for every glove-suture combination. All gloves were analyzed for perforation by a blinded evaluator using visual inspection, hydro-insufflation, and electroconductivity. RESULTS: The overall incidence of glove perforation was 3.4% and was detectable only by the electroconductivity method; the other 2 methods did not detect any perforations. There was a statistically significantly higher rate (P < .001) of perforations in the 0.32-mm powdered gloves (6.8%) compared with the 0.24-mm powder-free gloves (0%). Perforation of the inner glove occurred 5.7 times more frequently than perforation of the outer glove. However, simultaneous perforation of both the inner and outer gloves did not occur in any set. The Hi-Fi suture was involved in 6 perforations compared with 4 for FiberWire, 3 for Ultrabraid, and 0 for Orthocord. CONCLUSIONS: Double gloving provides an adequate surgical barrier between the surgeon and the patient during arthroscopic knot tying with high-tensile strength sutures as indicated by the low incidence of glove perforations in our study in an in vitro biomechanical evaluation. There were no instances of simultaneous perforation of both the inner and outer gloves. All perforations occurred only in the thicker (0.32-mm) powdered gloves. CLINICAL RELEVANCE: Glove tears and finger lacerations have been reported with the use of high-tensile strength sutures during arthroscopic shoulder surgery, thereby raising a concern for safety and disease transmission. This study addresses these concerns by evaluating the risk of glove tears during arthroscopic knot tying.

Central versus eccentric internal fixation of acute scaphoid fractures.

PURPOSE: To accurately calculate the cross-sectional area of typical scaphoid fracture patterns and compare the amount of fracture surface area available for healing when a screw was positioned in the center of the scaphoid (central) versus perpendicular (eccentric) to the fracture plane. METHODS: We employed a laser scanning technique to create 3-dimensional models of the scaphoid and permit the precise calculation of area along any cross-sectional cut of the bone. We computed approximate bone apposition areas for typical acute Herbert and Fisher fractures for 10 dry bone specimens. Next, we modeled internal fixation for each of these fracture geometries with screws placed either along the central axis of the scaphoid or eccentrically, perpendicular to the fracture plane. We calculated the proportional areas occupied by the screw and remaining area available for fracture healing. RESULTS: The mean surface area of the simulated distal oblique, complete waist, and proximal pole fractures was 131, 86, and 58 mm(2), respectively. There was little difference in available area for complete waist and proximal pole fractures, but eccentric screw fixation perpendicular to the plane in distal oblique fractures consumed significantly less area than the centrally placed position. CONCLUSIONS: The area available for apposition is widely variable and depends on each bone's unique morphology, the orientation of the fracture plane, and the design of the screw. Of the 3 fracture patterns studied, the obliquity of the screw with respect to the long axis was greatest for distal oblique fractures where perpendicular (eccentric) placement is preferable to maximize surface area available for healing. CLINICAL RELEVANCE: Given the poor vascular supply of the scaphoid and morbidity associated with scaphoid fracture nonunions, this study examined a key determinant of bone healing by characterizing the area of these fractures and amount of bone apposition available for blood flow and healing when internally fixed with a compression screw.

Insertion profiles of 4 headless compression screws.

PURPOSE: In practice, the surgeon must rely on screw position (insertion depth) and tactile feedback from the screwdriver (insertion torque) to gauge compression. In this study, we identified the relationship between interfragmentary compression and these 2 factors. METHODS: The Acutrak Standard, Acutrak Mini, Synthes 3.0, and Herbert-Whipple implants were tested using a polyurethane foam scaphoid model. A specialized testing jig simultaneously measured compression force, insertion torque, and insertion depth at half-screw-turn intervals until failure occurred. RESULTS: The peak compression occurs at an insertion depth of -3.1 mm, -2.8 mm, 0.9 mm, and 1.5 mm for the Acutrak Mini, Acutrak Standard, Herbert-Whipple, and Synthes screws respectively (insertion depth is positive when the screw is proud above the bone and negative when buried). The compression and insertion torque at a depth of -2 mm were found to be 113 ± 18 N and 0.348 ± 0.052 Nm for the Acutrak Standard, 104 ± 15 N and 0.175 ± 0.008 Nm for the Acutrak Mini, 78 ± 9 N and 0.245 ± 0.006 Nm for the Herbert-Whipple, and 67 ± 2N, 0.233 ± 0.010 Nm for the Synthes headless compression screws. CONCLUSIONS: All 4 screws generated a sizable amount of compression (> 60 N) over a wide range of insertion depths. The compression at the commonly recommended insertion depth of -2 mm was not significantly different between screws; thus, implant selection should not be based on compression profile alone. Conically shaped screws (Acutrak) generated their peak compression when they were fully buried in the foam whereas the shanked screws (Synthes and Herbert-Whipple) reached peak compression before they were fully inserted. Because insertion torque correlated poorly with compression, surgeons should avoid using tactile judgment of torque as a proxy for compression. CLINICAL RELEVANCE: Knowledge of the insertion profile may improve our understanding of the implants, provide a better basis for comparing screws, and enable the surgeon to optimize compression.

Telemedicine-guided forearm emergency decompressive fasciotomy for compartment syndrome.

INTRODUCTION: We highlight the utility of telemedicine and telementoring for the management of orthopaedic emergencies using a case of forearm compartment syndrome following a penetrating trauma in a northern Inuit community in Nunavik, Quebec, Canada. METHODS & RESULTS: As in many cases of compartment syndrome in rural settings, the patient was at a high risk of developing irreversible complications. A prompt diagnosis followed by an emergency decompressive fasciotomy was warranted. Using telemedicine and telementoring guidance, the diagnosis of compartment syndrome was made, and the patient's volar compartment was successfully decompressed by a local emergency physician in a timely manner. Subsequently, the patient was able to be safely transferred to a level 1 trauma centre for further surgical management. This included a second-look operative exploration, irrigation and debridement, completion of volar fasciotomy and ulnar nerve decompression. No complications were seen. DISCUSSION: Our experience highlights two important clinical implications. First, telemedicine can be successfully implemented to facilitate clinical diagnosis of surgical emergencies in the rural setting. Second, telementoring can effectively allow surgeons to guide physicians remotely to perform emergency decompressive fasciotomy, which can help salvage the affected limb and significantly decrease the risk of debilitating complications.

Using an Affordable Motion Capture System to Evaluate the Prognostic Value of Drop Vertical Jump Parameters for Noncontact ACL Injury.

BACKGROUND: Knee kinematic parameters during a drop vertical jump (DVJ) have been demonstrated to be associated with increased risk of noncontact anterior cruciate ligament (ACL) injury. However, standard motion analysis systems are not practical for routine screening. Affordable and practical motion sensor alternatives exist but require further validation in the context of ACL injury risk assessment. PURPOSE/HYPOTHESIS: To prospectively study DVJ parameters as predictors of noncontact ACL injury in collegiate athletes using an affordable motion capture system (Kinect; Microsoft). We hypothesized that athletes who sustained noncontact ACL injury would have larger initial and peak contact coronal abduction angles and smaller peak flexion angles at the knee during a DVJ. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: 102 participants were prospectively recruited from a collegiate varsity sports program. A total of 101 of the 102 athletes (99%) were followed for an entire season for noncontact ACL injury. Each athlete performed 3 DVJs, and the data were recorded using the motion capture system. Initial coronal, peak coronal, and peak sagittal angles of the knee were identified by our software. RESULTS: Five of the 101 athletes sustained a noncontact ACL injury. Peak coronal angles were significantly greater and peak sagittal flexion angles were significantly smaller in ACL-injured athletes (P = .049, P = .049, respectively). Receiver operating characteristic (ROC) analysis demonstrated an area under the curve of 0.88, 0.92, and 0.90 for initial coronal, peak coronal, and peak sagittal angle, respectively. An initial coronal angle cutoff of 2.96° demonstrated 80% sensitivity and 72% specificity, a peak coronal angle cutoff of 6.16° demonstrated 80% sensitivity and 72% specificity, and a peak sagittal flexion cutoff of 93.82° demonstrated 80% sensitivity and 74% specificity on the study cohort. CONCLUSION: Increased peak coronal angle and decreased peak sagittal angle during a DVJ were significantly associated with increased risk for noncontact ACL injury. Based on ROC analysis, initial coronal angle showed good prognostic ability, whereas peak coronal angle and peak sagittal flexion provided excellent prognostic ability. Affordable motion capture systems show promise as cost-effective and practical options for large-scale ACL injury risk screening.