Percutaneous fixation of scaphoid fractures has become popular in recent years, mainly due to its reduced complexity compared to open surgical approaches. Fluoroscopy is currently used as guidance for this percutaneous approach, however, as a projective imaging modality, it provides only a 2D view of the complex 3D anatomy of the wrist during surgery, and exposes both patient and physician to harmful X-ray radiation. To avoid these drawbacks, 3D ultrasound has been suggested to provide imaging for guidance as a widely available, real-time, radiation-free and low-cost modality. However, the blurred, disconnected, weak and noisy bone responses render interpretation of the US data difficult so far. In this work, we present the integration of 3D ultrasound with a statistical wrist model to allow development of an improved ultrasound-based guidance procedure. For enhancement of bone responses in ultrasound, a phase symmetry based approach is used to exploit the symmetry of the ultrasound signal around the expected bone location. We propose an improved estimation of the local phase symmetry by using the local spectrum variation of the ultrasound image. The statistical wrist model is developed through a group-wise registration based framework in order to capture the major modes of shape and pose variations across 30 subjects at different wrist positions. Finally, the statistical wrist model is registered to the enhanced ultrasound bone surfaces using a probabilistic registration approach. Feasibility experiments are performed using two volunteer wrists, and the results are promising and warrant further development and validation to enable ultrasound guided percutaneous scaphoid fracture reduction

Obesity is associated with worse outcomes following total knee/hip arthroplasty (TKA/TKA). This study aimed to determine the feasibility of a dietitian-led low-inflammatory weight-loss program for people with obesity awaiting arthroplasty.

Quasi-experimental pilot study enrolled people with obesity waitlisted for primary TKA/THA into ‘usual care’ (UC) or weight-loss (low-inflammatory diet) program (Diet). Recruitment occurred between July 2019 and February 2020 at Fairfield and Campbelltown Hospitals. Assessments at baseline, pre-surgery, time of surgery and 90-days following surgery included anthropometric measurements, patient-reported outcomes, serum biomarkers and 90-day postoperative complication rate.

97 people consented to the study (UC, n=47, mean age 67, BMI 37, TKA 79%; Diet, n=50, mean age 66, BMI 36, TKA 72%). Baseline characteristics indicated gross joint impairments and poor compliance with a low-inflammatory diet. Study feasibility criteria included recruitment rate (52%), proportion of diet patients that improved compliance to low-inflammatory diet by ≥10% (57%) and had ≥60% attendance of dietitian consultations (72%), proportion of patients who undertook serum biomarkers (55%).

By presurgery assessments, the diet group had more patients who cancelled their surgery due to symptom improvement (4 vs 0), reduced waist-circumference measurements, increased compliance with the Low-Inflammatory diet and preservation of physical activity parameters. More usual care participants experienced at least one postoperative complication to 90-days (59% vs 47%) and were discharged to inpatient rehabilitation (21% vs 11%). There was no difference in weight change, physical function, and patient-reported outcome measures from pre-surgery to 90-days post-surgery, and length of hospital stay.

Using pre-determined feasibility criteria, conducting a definitive trial is not feasible. However, intervention audit demonstrated high intervention fidelity.

Pilot data suggest our program may promote weight loss but the clinical effects for most are modest. Further research utilising a stronger intervention may be required to assess the effectiveness of a pre-arthroplasty weight-loss intervention.

Knee arthroscopy is typically approached from the anterior, posteromedial and posterolateral portals. Access to the posterior compartments through these portals can cause iatrogenic cartilage damage and create difficulties in viewing the structures of the posterior compartments. The purpose of this study was to assess the feasibility of needle arthroscopy using direct posterior portals as both working and visualising portals.

For workability, the needle scope was inserted advanced from anterior between the cruciate ligament bundle and the lateral wall of the medial femoral condyle until the posterior compartments were visualised. For visualisation, direct postero-lateral and -medial portals were established. The technique was performed in 9 knees by two experienced researchers.

Workability and instrumentation of the posteromedial compartment and meniscus was achieved in 56%. The posterior horns could not be visualised in four specimens as the straight lens could not provide a more medial field of view. Visualisation from the direct medial posterior portal allowed a clear view of the medial meniscus, femoral condyle and posterior cruciate ligament in all specimens. Workability and instrumentation of the posterolateral compartment was not possible with the needle scope.

Direct posterior approaches for the posteromedial compartment access are challenging with the current needle scope options and could only be achieved in over 50%. The postero-lateral compartment was not accessible. An angled lens or a flexible Needle scope would be better suited for developing this technique further.

Conventional fracture courses utilise prefabricated sawbones that are not realistic or patient specific. The aim of this study is to determine the feasibility of creating 3D fracture models and utilising them in fracture courses to teach surgical technique.

We selected an AO type 2R3C2 fracture that underwent open reduction internal fixation. De-identified CT scan images were converted to a stereolithography (STL) format. This was then processed using Computer Aided Design (CAD) to create a virtual 3D model. The model was 3D printed using a combination of standard thermoplastic polymer (STP) and a porous filler to create a realistic cortical and cancellous bone. A case-based sawbone workshop was organised for residents, unaccredited registrars, and orthopaedic trainees comparing the fracture model with a prefabricated T-split distal radius fracture. Pre-operative images aided discussion of fixation, and post-operative x-rays allowed comparison between the participants fixation. Participants were provided with identical reduction tools. We created a questionnaire for participants to rate their satisfaction and experience using a Likert scale.

The 3D printed fracture model aided understanding and appreciation of the fracture pattern and key fragments amongst residents and unaccredited trainees. Real case-based models provided a superior learning experience and environment to aid teaching. The generic sawbone provided easier drilling and inserting of screws. Preliminary results show that the cost of 3D printing can be comparable to generic sawbones.

It is feasible to create a fracture model with a real bone feel. Further research and development is required to determine the optimum material to use for a more realistic feel.

The use of 3D printed fracture models is feasible and provides an alternative to generic sawbone fracture models in providing surgical training to residents.

Advances in algorithms developed with sensor data from smart phones demonstrates the capacity to passively collect qualitative gait metrics. The purpose of this feasibility study was to assess the recovery of these metrics following joint reconstruction. A secondary data analysis of an ethics approved global, multicenter, prospective longitudinal study evaluating gait quality data before and after primary total knee arthroplasty (TKA, n=476), partial knee arthroplasty (PKA, n=139), and total hip arthroplasty (THA, n=395). A minimum 24 week follow-up was required (mean 45±12, range 24 - 78). Gait bouts and gait quality metrics (walking speed, step length, timing asymmetry, and double support percentage) were collected from a standardized smartphone operating system. Pre- and post-operative values were compared using paired-samples t-tests (p<0.05).

A total of 595 females and 415 males with a mean age of 61.9±9.3 years and mean BMI of 30.2±6.1 kg/m² were reviewed. Walking speeds were lowest at post-operative week two (all, p<.001). Speeds exceeded pre-operative means consistently by week 21 (p=0.015) for PKA, and week 13 (p=0.007) for THA. The average weekly step length was lowest in post-operative week two (all, p<0.001). PKA and THA cases achieved pre-operative step lengths by week seven (p=0.064) and week 9 (p=0.081), respectively. The average weekly gait asymmetry peaked at week two post-operatively (all, p <0.001). Return to pre-operative baseline asymmetry was achieved by week 11 (p=0.371) for TKA, week six (p=0.541) for PKA, and week eight (p=.886) for THA. Double limb support percentages peaked at week two (all, p<0.001) and returned to pre-operative levels by week 24 (p=0.089) for TKA, week 12 (p=0.156) for PKA, and week 10 (p=0.143) for THA.

Monitoring gait quality in real-world settings following joint reconstruction using smartphones is feasible, and may provide the advantage of removing the Hawthorne effect related to typical gait assessments and in-clinic observations.

Introduction

Recent advances in algorithms developed with passively collected sensor data from smart phones and watches demonstrate new, objective, metrics with the capacity to show qualitative gait characteristics. The purpose of this feasibility study was to assess the recovery of gait quality following primary total hip and knee arthroplasty collected using a smartphone-based care platform.

In light of recent regulatory initiatives, medical devices now require additional clinical evidence to prove their safety and efficacy. At the same time, patients' own assessment of their devices' function and performance has gained in importance. The collection of these data allows for a more comprehensive picture of clinical outcomes and complications following total knee arthroplasty (TKA).

These trends have led researchers to search for new methods of acquiring, interpreting and disseminating patient-reported outcome measurements (PROMs). The current study assesses the feasibility of a digital platform for collecting PROMs that was recently adapted for TKA patients. It sought to determine patient engagement, survey completion rates, and satisfaction with this platform.

Eighty-two patients (mean age, 63.7 years, 59% females) scheduled for TKA were enrolled from one US and six UK sites between January 12, 2018 and April 30, 2018. Patients were supplied with a mobile application (app) that collects a variety of PROMs, including four domains based on the Patient-Reported Outcome Information System (PROMIS™): physical function, depression, pain interference and pain behavior. The platform electronically administers questionnaires using computer-adaptive tests (CATs), which reduce the burden on patients by tailoring follow-up questions to account for their previous answers. Satisfaction with the app was assessed in subset of patients who evaluated its ease-of-use (n=45), likelihood that they would recommend it to family/friends (n=35), and whether they successfully used the information it provided during their recovery (n=31). These scores were taken on a 1 to 10 (worst to best) scale.

Patients demonstrated regular engagement with the platform, with 73% using the app at least once a week. Weekly engagement remained high throughout the seven-week post-operative period (Figure 1). There was a 69% completion rate of all PROMIS™ CAT surveys during the study. The four PROMIS™ CAT domains had similar survey completion rates (Figure 2). The subset of patients queried regarding their satisfaction with the app gave it favorable mean scores for ease-of-use (8.8), likelihood to recommend to a family member or friend (8.1), and their success at using its information to improve their recovery (7.4).

Initial results support this digital platform's potential for successfully and efficiently collecting large volumes of PROMs. Patients reported high levels of engagement and satisfaction.

For any figures or tables, please contact authors directly.

Background

Total Knee Arthroplasty (TKA) provides patients with significant improvements in quality of life. Subjective patient reported outcome measures (PROMs) are traditionally used to measure preoperative functional status and postoperative outcomes. However, there are limitations to PROMs. In particular, they provide virtually no functional information in the first 3 weeks after surgery, which could be used to guide the patient's recovery. Newly available wearable electronic sensors make it possible to: 1) measure important functional outcomes following TKA; 2) guide the patient's physical therapy (PT); and 3) provide real-time functional and clinical information to the provider.

Compliance with PT after TKA is a challenge. Patients cite time, transportation, and cost as deterrents to PT appointments. However, an intensive PT program is essential in TKA. Surface sensor devices may be able to increase PT compliance by guiding patients through exercises at home. Additionally, these devices can transmit PT progress in real-time to the providers, allowing them to monitor and assist the patient's recovery.

Our study investigates the feasibility of using a surface sensor device (TracPatch™) on patients following TKA. We sought to answer the following questions: 1) Will patients tolerate the device; 2) Will patients comply with device instructions; 3) Will patients be able to use the smart phone application; 4) Will the device collect, transmit, and store data as it was designed? We believe these fundamental questions must be answered as we enter the era of personal sensor-measured functional outcomes.

Purpose

Reproducing a functional flexion-extension axis (FEA) of the femur is key to achieving successful collateral ligament balance and joint line in total knee arthroplasty (TKA). This study assessed the feasibility of cylindrical axis (CA)-reference bone-cut and articular surface-reference bone-cut to reproduce FEA in Japanese osteoarthritis patients.

Objectives

How to position a unicompartmental knee replacement (UKR) remains a matter of debate. We suggest an original technique based on the intra-operative anatomic and dynamic analysis of the operated knee by a navigation system, with a patient-specific reconstruction by the UKR. The goal of the current study was to assess the feasibility of the new technique and its potential pitfalls.

We introduce a novel active tensioning system that can be used for dynamic gap-based implant planning as well as for assessment of final soft tissue balance during implant trialing. We report on the concept development and preliminary findings observed during early feasibility testing in cadavers with two prototype systems.

Background:

Glenoid component loosening remains as an unsolved clinical problem in total shoulder arthroplasty. Current clinical assessment relies on subjective quantification using a two-dimensional plane X-ray image with arbitrarily defined criteria. There is a need to develop a readily usable clinical tool to accurately and reliably quantify the glenoid component motion over time after surgery. A high-resolution clinical CT has the potential to quantify the glenoid motion, but is challenged by metal artifact from the prosthetic humeral components. The objective of this study is to demonstrate the feasibility of using a clinical CT reconstruction to quantify the glenoid implant motion with the aid of tantalum markers.

Measurements of shoulder kinematics during activities of daily living (ADL) can be used to evaluate patient function before and after treatment and help define device testing conditions. However, due to the difficulties of making 3D motion measurements outside of laboratory conditions, there are few reports of measured shoulder 3D kinematics during ADL. The purpose of this study was to demonstrate the feasibility of using wearable inertial measurement units (IMUs) to track shoulder joint angles.

A nonrandom sample of 5 subjects with normal shoulders was selected based on occupation. The occupations were: dental hygienist, primary school teacher, mechanical project engineer, administrative assistant, and retail associate. Subjects wore two OPAL IMUs (APDM, Portland OR) as shown in Figure 1 on the sternum and on the upper arm for approximately 4 hours while at their workplace performing their normal work place activities and then up to 4 hours while off-work.

Orientation angles from IMUs have traditionally been estimated by integrating gyroscope data and calculating inclination angles relative to gravity with accelerometers. A significant problem is that inaccuracies inherent in the measurements can degrade accuracy. In this study, we used an Unscented Kalman Filter (UKF) with IMU output to track shoulder angles. The UKF mitigates the effect of random drift by incorporating domain knowledge about the shoulder normal range of motion, and the gyroscope and accelerometer characteristics into the state-space models. Initially, in the horizontal plane, without gravity measurements from the accelerometer to aid the gyroscope data, there were unacceptable errors in transverse rotation. To mitigate this error, additional constraints were applied to model gyroscope drift and a zero velocity update strategy was included. These additions decreased tracker errors in heading by 63%. The resulting accuracy with the modified tracker in all motion planes was about 2° (Figure 2).

Subjects commented that the IMUs were well tolerated and did not interfere with their ability to perform tasks in a normal manner. The overall averaged 95th percentile angles (Figure 3) were: flexion 128.8°, adduction 128.4°, and external rotation 69.5°. These peaks angles are similar to other investigator's reports using laboratory simulations of ADL tasks measured with optical and electromagnetic technologies, though this study's observations did show 17% greater extension and 40% greater adduction. Additionally, in these observations, occurrences of maximal internal rotation were rare compared to maximal external rotation and when maximum external rotation did occur, it was in combination with an average flexion angle of 103°. Finally, by performing a Fourier transform of the arm angles and using the 50th percentile frequency the number of arm cycles in a 10 year period was calculated at over 600,000 cycles.

Application of the UKF with the additional drift correction made substantial improvements in shoulder tracking performance and this feasibility data suggests that IMUs with the UKF are suitable for extended use outside of laboratory settings. The motion data collected provides a novel description of arm motion during ADLs including estimating the cycle count of the upper arm at more than 600,000 cycles over 10 years.

Hip fracture is a common cause of hospital admission and is often followed by reduced quality of life, or by death. International experiences indicate there are many benefits to be gained from national hip fracture registries. This pilot project aims to implement a hip fracture registry at three sites, a large metropolitan public hospital (Flinders Medical Centre), a large metropolitan private hospital (Epworth HealthCare) and a rural regional hospital (Goulburn Valley Health) to assess the feasibility of establishing a national registry.

Patients undergoing surgery for a hip fracture will be recruited from the three participating hospitals between March and September 2009. A minimum data set will be collected at discharge, from hospital records. Items include patient demographics, fracture descriptors, length of stay, residential status, mobility, health status, surgical details and discharge destination. A phone interview at four months after surgery will measure outcomes by using the Extended Glasgow Outcomes Scale and documenting residential status, mobility, hip pain and readmissions. Re- operations, if any, will be collected. The availability of data from State Health Departments for validation of hospital case data will be reported.

The pilot study is in progress at the time of writing. Ethical approval has been obtained, data collection, transmission and storage systems have been developed and deployed, and case data collection is underway. Case data will be summarised to describe hip fracture at the participating hospitals. Analysis will review the data elements in the pilot data set and assess their priority for inclusion in a national register—taking account of the quality of the data obtained and the time and other resources required for their collection. We will also evaluate the four-month review process. Any potential obstacles to a national registry that are identified during the pilot will be described and ways to overcome them will be proposed.

A national hip fracture registry will improve the quality of care and safety of patients following hip fracture by developing an efficient mechanism to compare and improve the effectiveness of acute health care delivery by all hospitals involved in the management of hip fractures.

Introduction

Computer aided surgery aims to improve surgical outcomes with image-based guidance. Navigated Freehand bone Cutting (NFC) takes this further by eliminating the need for cumbersome mechanical jigs. Multiple previous experiments on plastic and porcine bones, performed by surgeons with different level of expertise, suggested that the NFC technique was feasible. This study pushes NFC further by using the technique to perform complete total knee replacement (TKR) surgeries on cadavers (including implant cementing of tibia and femur).

Introduction

Kinematics tracking is the process by which the motion of the joints is studied. This motion consists of relative rotation and translation of the joint bones. Joint motion analysis is used in diagnosis of joint pathology, as well as studying the normal joint function. Currently, fluoroscopy is used in joint kinematics tracking. We are researching the use of pulse-echo A-mode ultrasound for the bone motion tracking instead of the fluoroscopy to avoid its radiation. In this work we performed feasibility study using simulation, and concluded that it is feasible to perform knee motion tracking with accuracy of 2 mm.

In combined high median and ulnar nerve injury, transfer of extensor digiti minimi (EDM) and extensor carpi ulnaris (ECU) nerve branches to restore intrinsic hand function is previously described. A segment of nerve graft is required in this operation. The aim of this study was to evaluate the feasibility of using the sensory branch of radial nerve (SRN) as an “in situ vascular nerve bridge'” (IVNB) instead of sural nerve graft.

Twenty fresh cadavers were dissected. In proximal forearm incision, the feasibility of transferring the EDM/ECU branches to the distal stump of transected SRN was evaluated. In distal forearm incision, the two distal branches of the SRN were transected near the radial styloid process to determine whether transfer of the proximal stumps of these branches to the motor branches of the median (MMN) and ulnar (MUN) nerves is possible. The number of axons in each nerve was determined.

The size of the dissected nerves and their location demonstrate that tension free nerve coaptation is easily possible in both proximal and distal incisions.

Utilisation of the SRN as an IVNB instead of the conventional sural nerve graft has some advantages. Firstly, the sural nerve graft is a single branch and could be sutured to either the MMN or MUN, whereas the SRN has two terminal branches and can address both of them. Secondly, the IVNB has live Schwann cells and may accelerate the regeneration. Finally, this IVNB does not require leg incision and could be performed under regional anesthesia. The SRN as an IVNB is a viable option which can be used instead of conventional nerve graft in some brachial plexus or high median and ulnar nerve injuries when restoration of intrinsic hand function by transfer of EDM/ECU branches is attempted.

Direct arthroscopic cartilage assessment remains the gold standard. It is recommended by the International Cartilage Repair Society (ICRS) to systematically assess cartilage status during arthroscopy but this examination is highly subjective, poorly reproducible, time-consuming and lacks precision. US has shown good potential for cartilage evaluation but is limited in extra-articular conditions. It is also difficult to manually maintain a perfect perpendicularity between the ultrasound beam and the curved surface of the cartilage. Therefore, we have developed a navigated intra-articular US probe (NIAUS). The NIAUS probe could contribute to a more exhaustive and direct intra-articular evaluation of cartilage integrity. Navigation enables control of the US echo pulse perpendicularity and its localisation relative to the joint. Our objectives were (1) to evaluate automatic cartilage thickness measurement with the NIAUS probe in comparison to high definition MRI on cartilage samples, (2) to generate a real-time 3D map of the thickness parameter on samples, and (3) to demonstrate the feasibility of a full NIAUS probe cartilage scan on a specimen distal femur in arthroscopic conditions.

The NIAUS probe is a 4.5mm probe consisting of a 64 element linear array transducer with a central frequency of 13 MHz and a motorised head. The NIAUS probe is navigated. The rotating US head position is controlled by navigation in order to enable constant perpendicular acquisition of cartilage. The NIAUS probe thickness measurement (1) was evaluated on bone and cartilage samples of 9 tibial plateaus. The cartilage thickness was measured via automatic segmentation. Each sample was also scanned in a high resolution MRI (4,7 Tesla) and cartilage thickness was semi-automatically extracted for comparison. During NIAUS scan, (2) a visual 3D map was generated. Finally (3), we scanned two distal femurs with the NIAUS probe in arthroscopic navigated conditions on one specimen and a 3D map of the distal femur thickness was generated in real time.

NIAUS thickness measurement (1) absolute error compared to MRI for 9 plateaus ranged from 0.15mm to 0.32mm in median, p25=0.07 and 0.18, p75=0.28 and 0.5 respectively. 3D maps of the sample cartilage thickness (2) were generated in real time during the NIAUS scan. The cadaveric procedure (3) was conducted without incident via the two anterior portals and a 3D map of the distal femurs cartilage thickness was generated.

A precise US arthroscopic grading and scoring of cartilage during surgery could help for better standardisation, prediction of results and making “live” decisions. Our in vitro experiment shows good results compared to MRI for NAIUS cartilage thickness measurement, and our cadaveric study demonstrate the feasibility of a NIAUS scan in arthroscopic conditions. Our results are encouraging and a clinical trial is currently being designed for preliminary in vivo NIAUS evaluations of cartilage thickness compared to MRI.

Introduction. Direct skeletal attachment of prosthetic limbs, commonly known as osseointegration (“OI”), is being investigated by our team with the goal of safely introducing this technology into the United States for human use. OI technology allows for anchorage of prosthetic devices directly to bone using an intramedullary stem. For OI to be effective and secure, bone ingrowth and remodeling around the implant must be achieved. Physicians need an effective way to measure bone remodeling in order to make informed decisions on prescribed loading. This work describes methodology that was developed that utilizes computed tomography (CT) imaging as a tool for analyzing bone remodeling around an osseointegrated implant. Method. A subject implanted with a new Percutaneous Osseointegrated Prosthesis (POP) (DJO Surgical, Austin, TX) had CTs taken of their residual femur at 6-weeks and 12-months post-op in a FDA Early Feasibility Study with Institutional Review Board approval. Three-dimensional models of the femur were created from dicom files of the CT slices using Mimics (v21.0, Materialise, Leuven, Belgium). Each scan was segmented into four objects: cortical bone, medullary cavity, total volume (cortical bone plus the medullary cavity) and endoprosthetic stem (Fig. 1). Following segmentation, models were uploaded to 3-Matic Research (v13.0, Materialise, Leuven, Blegium) in STL format for alignment to a common world coordinate system (Fig. 2). A common origin was set by taking the average distance between planes of the femoral head and the greater trochanter. Once aligned to the coordinate system, biomechanical length (BML) was calculated from the proximal origin to the distal end of the amputated femur. BML and STLs of the aligned medullary cavity and femur volume were entered into custom Matlab code designed to measure cortical and medullary morphology in transverse cross sections of the femur. Morphology data from 6-weeks and 12-month time points were compared in order to determine if bone remodeling around the POP implant could be detected using these methods. Results. Comparing longitudinal data from post-operative visits suggests that important indicators of bone remodeling around the device could be detected (Fig 3). One year after implantation of the POP device the medullary perimeter and area had minimal % differences (−1.5 and 2.2) from the 6-week visit, validating that consistent alignment of the femoral model was achieved between scans from different time points. The cortical area, cortical perimeter, and cortical thickness around the POP implant showed positive percent changes at the 12-months of 19.44%, 4.04% and 14.36% respectively, with the largest increases observed at the the distal end for each parameter. These increases in cortex morphology values indicate bone changes were identified around the endoprosthetic stem of the implant. Discussion/Conclusion. This pilot study utilized CT imaging as a tool for analyzing bone remodeling around a new osseointegrated device. These methods can be performed quickly and accurately and have the potential for use in monitoring bone remodeling. CT scans from additional subjects are being analyzed to further validate and optimize these methods for clinical use. This study described an investigational device, limited by federal law to investigational use. No long-term data exists about its performance. For any figures or tables, please contact the authors directly

Aims

Patients undergoing limb reconstruction surgery often face a challenging and lengthy process to complete their treatment journey. The majority of existing outcome measures do not adequately capture the patient-reported outcomes relevant to this patient group in a single measure. Following a previous systematic review, the Stanmore Limb Reconstruction Score (SLRS) was designed with the intent to address this need for an effective instrument to measure patient-reported outcomes in limb reconstruction patients. We aim to assess the face validity of this score in a pilot study.