Introduction. The accuracy of hexapod circular external fixator deformity correction is contingent on the precision of radiographic analysis during the planning stage. The aim of this study was to compare the SMART TSF (Smith and Nephew, Memphis, Tennessee) in-suite radiographic analysis methods with the traditional manual deformity analysis methods in terms of accuracy of correction. Materials and Methods. Sawbones models were used to simulate two commonly encountered clinical scenarios. Traditional manual radiographic analysis and digital SMART TSF analysis methods were used to correct the simulated deformities. Results. The final outcomes of all six analysis methods across both simulated scenarios were satisfactory. Any differences in residual deformity between the analysis methods are unlikely to be clinically relevant. All three SMART TSF digital analyses were faster to complete than manual radiographic analyses. Conclusions. With experience and a good understanding of the software, manual radiographic analysis can be extremely accurate and remains the gold standard for deformity analysis. In-suite SMART TSF radiographic analysis is fast and accurate to within clinically relevant parameters. Surgeons can with confidence trust the SMART TSF software to provide analysis and corrections that are clinically acceptable

Introduction & Aims. In other medical fields, smart implantable devices are enabling decentralised monitoring of patients and early detection of disease. Despite research-focused smart orthopaedic implants dating back to the 1980s, such implants have not been adopted into regular clinical practice. The hardware footprint and commercial cost of components for sensing, powering, processing, and communicating are too large for mass-market use. However, a low-cost, minimal-modification solution that could detect loosening and infection would have considerable benefits for both patients and healthcare providers. This proof-of-concept study aimed to determine if loosening/infection data could be monitored with only two components inside an implant: a single-element sensor and simple communication element. Methods. The sensor and coil were embedded onto a representative cemented total knee replacement. The implant was then cemented onto synthetic bone using polymethylmethacrylate (PMMA). Wireless measurements for loosening and infection were then made across different thicknesses of porcine tissue to characterise the sensor's accuracy for a range of implantation depths. Loosening was simulated by taking measurements before and after compromising the implant-cement interface, with fluid influx simulated with phosphate-buffered saline solution. Elevated temperature was used as a proxy for infection, with the sensor calibrated wirelessly through 5 mm of porcine tissue across a temperature range of 26–40°C. Results. Measurements for loosening and infection could be acquired simultaneously with a duration of 4 s per measurement. For loosening, the debonded implant-cement interface was detectable up to 10 mm with 95% confidence. For temperature, the sensor was calibrated with a root mean square error of 0.19°C at 5 mm implantation depth and prediction intervals of ±0.38°C for new measurements with 95% confidence. Conclusions. This study has demonstrated that with only two onboard electrical components, it is possible to wirelessly measure cement debonding and elevated temperature on a smart implant. With further development, this minimal hardware/cost approach could enable mass-market smart arthroplasty implants

Introduction. Evaluation of post-operative soft tissue balancing outcomes after Total Knee Arthroplasty (TKA) and other procedures can be measured by stability tests, with Anterior-Posterior (AP) drawer tests and Varus-Valgus (VV) ligamentous laxity tests being particularly important. AP stability can be quantified using a KT1000 device; however there is no standard way of measuring VV stability. The VV test relies on subjective force application and perception of laxity. Therefore we sought to develop and validate a device and method for quantifying knee balancing by analyzing VV stability. Materials and Methods. Our team developed a Smart Knee Fixture to measure VV angular changes using two dielectric elastomer stretch sensors, placed strategically over the medial and lateral collateral ligaments (see Figure 1). The brace is secured in position with the leg in full extension and the sensors locked with pre-tension. Therefore, contraction and elongation of either sensor is measured and the VV angular deviation of the long axis of the femur relative to that of the tibia is derived and displayed in real time using custom software. EMG muscle activity was previously investigated to confirm there is no resistive activity during the VV test obstructing ligamentous evaluations. The device was validated in two ways:. A bilateral lower body cadaver specimen, secured in a custom test rig, was used to compare the Smart Knee Fixture's readings to those measured from an optical surgical navigation system. Abduction and adduction force was gradually applied as varus and valgus moments with a wireless hand-held dynamometer up to 50N (19.8Nm) at 0 and 15° flexion. Two male volunteers were used to compare the Smart Knee Fixture's readings to those measured from fluoroscopic images. An arthroscopic distal thigh leg immobilizer was used to prevent rotation and lateral movements of the thigh when moments were applied at the malleoli. A C-arm Fluoroscope was then positioned focusing on the center of the joint. The tests were performed at full extension, 10 and 20° of flexion and force was gradually applied to 50N. Results and Discussion. R values were calculated to validate the Smart Knee Fixture's accuracy. Excellent correlation was observed between the Smart Knee Fixture and the gold standard of navigation (see Figure 2). The R values were 0.9909 and 0.9966. Correlation was also observed between Smart Knee Fixture and the measured fluoroscopic angular changes. The R values were 0.9118 and 0.7529. Conclusions. The strong R values allow us to conclude that the Smart Knee Fixture can potentially be used to accurately measure VV angular changes in a clinical setting and hence provide a quantified measure of coronal plane soft tissue balance. Clinical studies are underway to compare TKA patient outcomes to balancing measured by the Smart Knee Fixture. This information should further define balancing goals at the time of surgery. We also envisage broader applications to early detection of ligamentous injury associated with sporting activities, such as multiple ligamentous knee injuries in teenage females

The surgical correction of hammer digits offers a variety of surgical treatments ranging from arthroplasty to arthrodesis, with many options for fixation. In the present study, we compared 2 buried implants for arthrodesis of lesser digit deformities: a Smart Toe® implant and a buried Kirschner wire. Both implants were placed in a prepared interphalangeal joint, did not violate other digital or metatarsal joints, and were not exposed percutaneously. A retrospective comparative study was performed of 117 digits with either a Smart Toe® implant or a buried Kirschner wire, performed from January 1, 2007 to December 31, 2010. Of the 117 digits, 31 were excluded because of a lack of 90-day radiographic follow-up. The average follow-up was 94 to 1130 days. The average patient age was 61.47 (range 43 to 84) years. Of the 86 included digits, 48 were left digits and 38 were right. Of the digits corrected, 54 were second digits, 24 were third digits and 8 were fourth digits. Fifty-eight Smart Toe® implants were found (15 with 19-mm straight; 2 with 19-mm angulated; 34 with 16-mm straight; and 7 with 16-mm angulated). Twenty-eight buried Kirschner wires were evaluated. No statistically significant difference was found between the Smart Toe® implants and the buried Kirschner wires, including the rate of malunion, nonunion, fracture of internal fixation, and the need for revision surgery. Of the 86 implants, 87.9% of the Smart Toe® implants and 85.7% of the buried Kirschner wires were in good position (0° to 10° of transverse angulation on radiographs). Osseous union was achieved in 68.9% of Smart Toe® implants and 82.1% of buried Kirschner wires. Fracture of internal fixation occurred in 12 of the Smart Toe® implants (20.7%) and 2 of the buried Kirschner wires (7.1%). Most of the fractured internal fixation and malunions or nonunions were asymptomatic, leading to revision surgery in only 8.6% of the Smart Toe® implants and 10.7% of the buried Kirschner wires. Both the Smart Toe® implant and the buried Kirschner wire offer a viable choice for internal fixation of an arthrodesis of the digit compared with other studies using other techniques

Excellent outcomes following total hip arthroplasty require both optimal soft-tissue management and precise planning and placement of prosthetic components. The use of detailed and dynamic three-dimensional surgical plans combined with smart mechanical instruments for component placement facilitates precise and efficient surgery. Interest in these technologies has increased recently as surgeons and institutions are now responsible for poor outcomes in a growing percentage of the patient population. Cloud-based, patient-specific planning allows the surgeon to review and refine and execute surgical plans efficiently (HipXpert System, Surgical Planning Associates, Boston, MA). The surgical plans include cup size, cup orientation, stem size, head length, femoral anteversion, and planned change in leg length and offset, all in relation to the patients bony anatomy in 3D and multiplanar views. The associated smart tool is adjusted specifically for that patient and when docked, provides orientation information to the surgeon. The system has been proven to be robust, with repeated studies showing accurate cup placement in 100% of cases including by an independent study. This compares to a recent study of robotic methods that 88% of inclination and 84% for anteversion and to even greater inaccuracy of conventional surgery. Cloud-based 3D planning combined with smart mechanical navigation of cup placement offers the optimum combination of accuracy, speed, and simplicity for solving the ubiquitous problems of component sizing, orientation, and version, offset, and leg length correction. Knowledge of component sizing pre-operatively can facility inventory management and allows the surgery team to better anticipate the surgeon's goals during the procedure

Introduction. While component malposition remains a major short and long term problem associated with total hip arthroplasty, enhanced technologies such as navigation and robotics have not yet been widely adopted. Both expense and increased OR time can be obstacles to adoption. The current study assesses the effect of the use of a smart mechanical navigation system on surgery time in total hip arthroplasty. Patients and Methods. 514 consecutive primary total hip arthroplasties were performed by a single surgeon from January 1, 2015 through March 31, 2016. Of these, 40 were performed using a smart mechanical navigation system (the HipXpert System, Surgical Planning Associates Inc., Boston, Massachusetts) and 474 were performed without navigation. The patients were not randomized. Incision to closure time (surgery time) was recorded for each procedure. A two tailed t-test was performed to assess statistical significance. Results. Mean surgery time for the non-navigated cases was 66 minutes. Mean surgery time for the navigated cases was 70 minutes. The difference in surgery time between the two groups was statistically significant (p=0.003). Conclusion. Adoption and use of a smart mechanical navigation system has a measurable increase in OR time of 4 minutes. This increase in OR time is quite small and with experience, is likely to further decrease. The amount of surgery time necessary for the use of the system is small compared to traditional navigation systems and especially to robotic systems. The study demonstrates that the adoption of a new smart mechanical navigation system increased surgery time very little. We anticipate that increased experience with the system will allow for the reduction in the need for intraoperative radiographs, which will further decrease surgery time and associated cost while simultaneously improving accuracy

Pre-operative knowledge. Knowledge-based total hip arthroplasty is becoming increasingly recognised for improved safety, efficiency, and accuracy. Pre-operative knowledge of native and planned femoral anteversion, the exact size of implants, neck length and offset, and head lengths can serve to safely accelerate surgery and reduce the need for intra-operative imaging. Pre-operative knowledge of the effect on change in leg length and offset effected by specific implant combinations can serve to minimise undesired changes. The use of a smart mechanical navigation tool superimposed on this knowledge, can serve to easily and swiftly achieve optimal component position. Cost savings. Economic data from Q1 2013 to Q2 2016 demonstrate that CMS-insured patients treated by knowledge-based surgery using the HipXpert mechanical navigation system combined with the superior hip approach have the lowest cost of all patients treated in Massachusetts by an average of more than $7,000 over 90 days for Medicare Part A expenditure (HipXpert System, Surgical Planning Associates, Boston, MA). The data show that these combined techniques outpace all other technology/technique combinations including robotics. Accuracy. The system has been proven to be robust, with repeated studies showing accurate cup placement in 100% of cases including an independent study. This compares to a recent study of robotic methods that showed only 88% accuracy in inclination and 84% for anteversion. Summary. Knowledge-based surgery with smart mechanical navigation has shown the potential to accelerate surgery, improve safety, lower cost and facilitate recovery

Purpose. To evaluate whether continuous training and education of posture can help children to improve kyphosis. Method. A smart harness consisting of a tight-fitting harness and a posture sensing system was developed to measure kyphosis and to provide vibratory feedback during daily activities. The posture sensing system consisted of two sensor units and both units contained a 3-axis accelerometer and a 2-axis gyroscope to calculate the orientation. The dimensions and weight of each unit were 55 mm x 35 mm x 15 mm and 25g, respectively. One unit served as a master (placed at the T3 vertebral level) and the second unit served as a slave (placed at the T12 level) and they communicated wirelessly. The master unit calculated the kyphotic angle, similar to the vertebral centroid method but based on the sagital profile, and provided the vibratory feedback. One volunteer wore the unit and performed different postures and activities (walking, sitting, bending and sudden change from sitting to walking) in a gait analysis laboratory. The posture sensing system was sampled at 30Hz and a gait analysis 8-camera system was sampled at 60Hz. The kyphotic angles captured by the smart harness and camera system were compared. After this validation, the system was tested by 5 normal subjects (M, 25 10 years old) 3 hours per day for 4 consecutive days. For the first 2 days there was no feedback and the last 2 days there was feedback. The system took a sample every 30 seconds. When an undesirable posture was detected, the system switched to a fast sample mode at which time the system took ten measurements with a sample rate of 10 Hz for 1 second to further validate the measured kyphotic angle. These 10 measures were averaged to avoid feedback for postures that lasted only for a very short period of time. Posture orientation data was stored in the sensing unit memory and downloaded for outcomes evaluation. Results. Compared with the gait analysis camera system, the differences in the kyphotic angle during static and dynamic activities were 1.6 1.2, and 3.5 1.9 degrees, respectively. The largest error was 6.8 degrees which occurred during a dramatic change in posture during dynamic activities. The baseline data from the first 2 days (without feedback) showed the kyphotic angle was 48 12 degrees, during which time all subjects were working in front of a computer. The feedback days showed a slight improvement of kyphotic angles from day 1 to day 2, from 45 11 to 42 8 degrees, respectively. There was 12% improvement on day 2 when compared with the baseline data. Conclusion. This study showed the kyphotic angle could be fairly accurately measured using the smart harness. The kyphotic angle had a slight improvement when feedback was provided, however a longer clinical trial will be required to determine how lasting the effect will be

Total knees today are performed with the use of standard trials that the surgeon utilises to define appropriate implant rotation, range of motion, and soft tissue balance. This “feel” based approach is very subjective, and lacks a quantifiable approach to interpret our intra-operative knee assessment. Sensor-based trials are embedded into the specific knee designed tibial trial, and wirelessly displays data related to the implant's position and ligament tension. The surgeon can now identify malrotation, soft tissue imbalance, and instability through a full ROM. The surgeon can see dynamic responses to ligament releases, alignment changes, and implant adjustments. As Insall taught us; a TKR is a soft tissue procedure, and a “balanced” knee will demonstrate improved outcomes and greater patient satisfaction. Smart Trials allow us to discuss how our intra-operative techniques affect our patient's outcomes. This surgery will utilise Smart Trials during a Cruciate Retaining TKR

Acetabular component malalignment remains the single greatest root cause for revision THA with malposition of at least ½ of all acetabular components placed using conventional methods. The use of local anatomical landmarks has repeatedly proven to be unreliable due to individual variation of these structures. As a result, the use of such landmarks without knowledge of their three-dimensional orientation may actually be a major cause of component malpositioning. Traditional navigation and robotics can potentially lead to improved component placement but these technologies have not gained widespread use due to the increase in time of use, complexity, and cost of these systems. The alternative of placing the cup in the supine position, even with the use of arthroscopy, has been proven to have an incidence of inaccuracy equal or greater than that in the lateral position. A smart mechanical instrument system was developed to quickly and easily achieve accurate cup alignment (HipXpert System, Surgical Planning Associates, Boston, MA). The system is based on a low dose, low cost CT study and a customised patient-specific surgery plan. The laterally-based system docks on a patient-specific basis with 3 legs: one through the incision behind the posterior rim, one percutaneously on the lateral side of the ASIS, and a third percutaneously on the surface of the ilium. A direction indicator on the top of the instrument points in the desired cup orientation. The anteriorly-based system also docks on a patient-specific basis with one leg on the anterior ischium and one leg on each ASIS, either to skin or to bone. The lateral system has been proven to be robust, with repeated studies showing accurate cup placement in 100% of cases and an independent study showing accurate cup placement in 98% of cases. The newer anterior system has the potential for even greater accuracy. Smart mechanical navigation of cup placement offers the optimum combination of accuracy, speed, and simplicity for solving the ubiquitous problem of acetabular component malorientation

Major aspects on long-term outcome in Total Knee Arthroplasty are the correct alignment of the implant with the mechanical load axis, the rotational alignment of the components as well as good soft tissue balancing. To reduce the variability of implant alignment and at the same time minimise the invasiveness different computer assisted systems have been introduced. To achieve accuracy as high as those of a robotic system but with a pure mechanically adjustable cutting block, the Exactech GPS system has been developed. The new concept comprises a seamlessly planning and navigation screen with an integrated optical tracking system for fast and accurate acquisition and verification of anatomical landmarks within the sterile field as well as a tiny cutting guide for accurate transfer of the planned bone resections. Using a conventional screwdriver the cutting block could be accurately aligned with the planned resection by controlling the current position of the cutting block on the navigation screen. To save time, to maximise the ease of use and to minimize the surgeon's mental workload during adjustment, a smart screwdriver (SSD) has been developed being able to automatically adjust the screws. The basic idea of the smart screwdriver is to have a system providing an automatic transfer of the planned data to the cutting guide similar to a robotic system, but with the actuators separated from the kinematic. The use of the SSD is as simple as follows: After planning of the intervention and rigid fixation of the cutting guide on the bone, the surgeon simply connects sequentially the screwdriver to all screws of the cutting guide. To further maximise the ease of use and to avoid a mix-up of different screws, an identification means has been integrated into the positioning screws as well as into the smart screwdriver. For an automated identification of the screws different technologies have been analysed as position tracking, optical recognition or wired/wireless electronics. A first prototype without screw identification has been used successfully on 4 cadaver knees. All guide positions could be adjusted automatically using the SSD. However, the absence of screw identification required that the surgeon follows indications given by the computer to turn screws sequentially. A second prototype of the smart screwdriver has successfully been built up and is able to identify the different positioning screws in less than 1s with high reliability. The identification is realised as inductive coupling of different small resonance circuits that are integrated into the screw heads and the screwdrivers tip. To adjust the cutting guide from neutral to the planned position, the screws have to be adjusted by 5 mm in average. The rotational speed of the current SSD implementation is 2 rounds per second, resulting in a mean time of about 3.5 s for each screw adjustment. The rotational accuracy of the screwdriver is ±5°. Taking into account a thread of the positioning screws of 0.7 mm, the theoretical translational error is about ±0.01 mm. Looking at the angular accuracy, the maximum distance of the screws of the current setup of the cutting block of 15 mm results in an angular error of less than ±0.05°

Symptomatic flexion deformity of proximal interpahalangeal joint (PIPJ) is one of the most common foot deformities and usually treated with arthrodesis. In general, percutaneous K-wires are used to stabilize the joint after excision of cartilage. K-wires projecting out of the toe need special care and can occasionally be dislodged accidentally. Furthermore issues such as cellulitis, pin tract infections, rarely osteomyelitis and need for removal make alternative fixation methods desirable. Smart toe is an intra-osseous titanium memory implant, which is stored frozen. It expands on insertion and does not require removal. 18 consecutive K-wire PIPJ arthrodesis were compared with 18 Smart toe PIP fusions with a mean follow up of 6 months. Post operative forefoot scores and complications were documented. Patient satisfaction was higher and complications were lower with Smart toe fusions than with K-wire arthrodesis. Fusion of PIP joints with smart toe is an effective and safer alternative to using K-wires. Although more expensive, higher patient satisfaction and lower complication rate may offset the extra cost of the implant

In a study by Dickstein, one-third of total knee patients were not satisfied even though they were all thought to have had successful results by their orthopaedic surgeons. Noble and Conditt's study showed 14% of patients dissatisfied with their outcome with more than half expressing problems with routine activities of daily living. This occurs despite improvements in instrumentation to obtain proper alignment and implants with excellent kinematics and wear characteristics. Perhaps this dissatisfaction is a result of subtle soft tissue imbalance. Soft tissue imbalance can result in almost a third of early TKR revisions. Soft tissue balancing techniques still rely on subjective feel for appropriate ligamentous tension by the surgeon. Surgical experience and case volume play a major role in each surgeon's relative skill in balancing the knee properly. New technology of “smart trials” with embedded microelectronics, used in the knee with the medial retinaculum closed, can provide dynamic, intraoperative feedback regarding quantitative compartment pressures and component tracking. While visualising a graphical interface, the surgeon can assess the effect of sequential soft tissue releases performed to balance the knee. These smart trials also have imbedded accelerometers used to confirm that one is balancing a properly aligned knee and to provide the option of doing small bony corrections rather than soft tissue releases to obtain balance. A multi-center study using smart trials is demonstrating dramatically better outcomes at six months

Most orthopaedic surgeons believe that total knee replacement has superb patient outcomes. Long-term results are excellent, with one study showing 15 year survivorship of 97%. However, our objective assessments of our patients' results are greater than patients' subjective assessments. In a study by Dickstein of total knee patients, one-third were not satisfied even though they were all thought to have had successful results by their orthopaedic surgeons. Noble and Conditt's study showed 14% of patients dissatisfied with their outcome with more than half expressing problems with routine activities of daily living. We are puzzled by this patient dissatisfaction since radiographs usually show normal component alignment and positioning. Perhaps some of these patients have subtle soft tissue imbalance and kinematic maltracking. Excellent aligned bone cuts can be expected with modern instrumentation, especially if patient specific cutting instruments or computer navigation are used. However, inadequate instrumentation exists for soft tissue balancing. It is usually based on feel and visual estimation. Soft tissue balancing techniques are difficult to teach and perform by a less experienced surgeon. Smart trials with load bearing and alignment sensors, which can be used with the medial retinaculum closed, will demonstrate the total knee kinematics and quantify soft tissue balance. Graduated soft tissue balancing can be performed while visualising changes in compartment loads. Studies are ongoing with smart trials to establish evidence-based clinical algorithms for soft tissue balancing and document the effects of these techniques on patient satisfaction and long-term outcome

Fifteen-year survivorship studies demonstrate that total knee replacement has excellent survivorship, with reports of 85 to 97%. However, excellent survivorship does not equate to excellent patient reported outcomes. Noble et al. reported that 14% of their patients were dissatisfied with their outcome with more than half expressing problems with routine activities of daily living. There is also a difference in the patient's subjective assessment of outcome and the surgeon's objective assessment. Dickstein et al. reported that a third of total knee patients were dissatisfied, even though the surgeons felt that their results were excellent. Most of the patients who report lower outcome scores do so because their expectations are not being fulfilled by the total knee replacement surgery. Perhaps this dissatisfaction is a result of subtle soft tissue imbalance that we have difficulty in assessing intra- and post-operatively. Soft tissue balancing techniques still rely on subjective feel for appropriate ligamentous tension by the surgeon. Surgical experience and case volume play a major role in each surgeon's relative skill in balancing the knee properly. New technology of “smart trials” with embedded microelectronics, used in the knee with the medial retinaculum closed, can provide dynamic, intra-operative feedback regarding quantitative compartment pressures and component tracking. While visualising a graphical interface, the surgeon can assess the effect of sequential soft tissue releases performed to balance the knee. These smart trials also have embedded accelerometers used to confirm that one is balancing a properly aligned knee and to provide the option of doing small bony corrections rather than soft tissue releases to obtain balance. A multi-center study using smart trials is demonstrating dramatically better outcomes

Introduction. Navigation of acetabular component orientation is still not commonly performed despite repeated studies that show that more than ½ of acetabular components placed during hip arthroplasty are significantly mal-positioned and that intra-operative radiographic assessment is unreliable. The current study uses postoperative CT to assess the accuracy of a smart mechanical navigation instrument system for cup alignment. Patients and Methods. Thirty seven hip replacements performed using a smart mechanical navigation device (the HipXpert System) had post-operative CT studies available for analysis. These post-operative CT studies were performed for pre- operative planning of the contralateral side, one to three years following the prior surgery. An application specific software module was developed to measure cup orientation using CT (HipXpert Research Application, Surgical Planning Associates Inc., Boston, Massachusetts). The method involves creation of a 3D surface model from the CT data and then determination of an Anterior Pelvic Plane coordinate system. A multiplaner image viewer module is then used to create an image through the CT dataset that is coincident with the opening plane of the acetabular component. Points in this plane are input and then the orientation of the cup is calculated relative to the AP Plane coordinate space according to Murray's definitions of operative anteversion and operative inclination. The actual cup orientation was then compared to the goal of cup orientation recorded when the surgery was performed using the system for acetabular component alignment. Results. For the thirty seven hips replacements, mean operative anteversion error was 1.1 degrees (SD 3.6, range −5.5 to 8.2). Mean operative inclination error was − 1.7 degrees (SD 3.0, range −8.0 to 5.6). There were no outliers in either anteversion or inclination. Conclusion. The current study demonstrates that the mechanical navigation system produces accurate cup alignment results as measured by post-operative CT and confirms the prior accuracy study performed using 2D/3D matching. This improved accuracy compared to robotic systems may be due to the wide-based nature of the docking mechanism and the elimination of the cumulative errors of registration and tracking inherent to more complex systems

An anaesthetist recently remarked that orthopaedic surgeons are ‘twice as strong as an ox but half as smart’. We set out to ascertain if this had any evidence basis by conducting an observational study. We compared 36 male orthopaedic surgeons to 40 male anaesthetists across 3 hospitals to ascertain if there was a significant difference between the two groups in terms of Intelligence Quotient (IQ) and strength. We tested the IQ of each doctor using an official MENSA IQ test. We assessed the strength as reflected by the grip strength using a hand-grip dynamometer. Un-paired t-tests were used to assess statistical significance. Orthopaedic surgeons had a significantly greater mean grip strength 47.25Kg (SD=6.95) compared to anaesthetists 43.83Kg (SD=7.57) (p=0.04). The mean IQ of orthopaedic surgeons was also significantly greater at 105.19 (SD=10.85) than anaesthetists at 98.38 (SD=14.45) (p=0.02). Furthermore, the IQ of orthopaedic surgeons seems to increase with increasing age and seniority (an IQ jump of 5 IQ points from Registrar to Consultant). We have concluded that this proverb should be revised to orthopaedic surgeons are as strong as an ox and twice as smart, although further studies are advocated to ascertain the IQ of Ox

Introduction. Navigation of acetabular component orientation is still not commonly performed despite repeated studies that show that more than ½ of acetabular components placed during hip arthroplasty are significantly malpositioned. 1. The current study uses postoperative CT to assess the accuracy of a smart mechanical navigation instrument system for cup alignment. Patients and Methods. Thirty seven hip replacements performed using a smart mechanical navigation device (the HipXpert System) had post-operative CT studies available for analysis. These post-operative CT studies were performed for pre-operative planning of the contralateral side, one to three years following the prior surgery. An application specific software module was developed to measure cup orientation using CT (HipXpert Research Application, Surgical Planning Associates Inc., Boston, Massachusetts). The method involves creation of a 3D surface model from the CT data and then determination of an Anterior Pelvic Plane coordinate system. A multiplaner image viewer module is then used to create an image through the CT dataset that is coincident with the opening plane of the acetabular component. Points in this plane are input and then the orientation of the cup is calculated relative to the AP Plane coordinate space according to Murray's definitions of operative anteversion and operative inclination. The actual cup orientation was then compared to the goal of cup orientation recorded when the surgery was performed using the system for acetabular component alignment. Results. For the thirty seven hips replacements, mean operative anteversion error was 1.1 degrees (SD 3.6, range −5.5 to 8.2). Mean operative inclination error was −1.7 degrees (SD 3.0, range −8.0 to 5.6). There were no outliers in either anteversion or inclination. Conclusion. The current study demonstrates that the mechanical navigation system produces accurate cup alignment results as measured by post-operative CT and confirms the prior accuracy study performed using 2D/3D matching. This improved accuracy compared to robotic systems. 4. may be due to the wide-based nature of the docking mechanism and the elimination of the cumulative errors of registration and tracking inherent to more complex systems

Accurate implant placement is important to the success of joint replacement surgery. Three dimensional pre-operative planning optimizing the ability to define the anatomy and select the desired implant and its location. Linking this information into implant and patient specific instrumentation has been termed smart instrumentation. Single use instruments contain the patient's topographical boney anatomy and implant information. This same information can be placed within a bone model and a reusable instrument placed onto the bone model can be adjusted to capture the information originally in the planning software. This instrument can then be placed into the surgical site, registered to the bone surfaces and used to modify the bone surfaces to replicate the surgical plan. These concepts, technology and devices have been developed and clinically tested in randomized clinical trials for shoulder arthroplasty

Fifteen-year survivorship studies demonstrate that total knee replacements have excellent survivorship, with reports of 85 to 97%. However, excellent survivorship does not equate to excellent patient reported outcomes. Noble et al. reported that 14% of their patients were dissatisfied with their outcome with more than half expressing problems with routine activities of daily living. There is also a difference in the patient's subjective assessment of outcome and the surgeon's objective assessment. Dickstein et al. reported that a third of total knee patients were dissatisfied, even though the surgeons felt that their results were excellent. Most of the patients who report lower outcome scores do so because their expectations are not being fulfilled by the total knee replacement surgery. Perhaps this dissatisfaction is a result of subtle soft tissue imbalance that we have difficulty in assessing intra-operatively and post-operatively. Soft tissue balancing techniques still rely on subjective feel for appropriate ligamentous tension by the surgeon. Surgical experience and case volume play a major role in each surgeon's relative skill in balancing the knee properly. New technology of “smart trials” with embedded microelectronics and accelerometers, used in the knee with the medial retinaculum closed, can provide dynamic, intra-operative feedback regarding knee quantitative compartment pressures and component tracking. After all bone cuts are made using the surgeon's preferred techniques, trial components with the sensor tibial trial are inserted and the knee is taken through a passive range of motion. After visualizing the resultant compartment pressures and tracking data on a graphical interface, the surgeon can decide if compartment loading differences are greater than 15 pounds whether to perform a soft tissue balance or minor bone recuts. If soft tissue balancing is chosen, pressure data can indicate where to perform the release and allow the surgeon to assess the pressure changes as titrated soft tissue releases are performed. A multi-center study using smart trials has demonstrated dramatically better outcomes out to three years