Abstract. Objectives. Three-dimensional visualisation of sonographic callus has the potential to improve the accuracy and accessibility of ultrasound evaluation of fracture healing. The aim of this study was to establish a reliable method for producing three-dimensional reconstruction of sonographic callus. Methods. A prospective cohort of ten patients with a closed tibial shaft fracture managed with intramedullary nailing were recruited and underwent ultrasound scanning at 2-, 6- and 12-weeks post-surgery. Ultrasound B-mode capture was performed using infrared tracking technology to map each image to a three-dimensional lattice. Using echo intensity, semi-automated mapping was performed by two independent reviewers to produce an anatomic three-dimensional representation of the fracture. Agreement on the presence of sonographic bridging callus on three-dimensional reconstructions was assessed using the kappa coefficient. Results. Nine of the ten patients achieved union at six months. At six weeks, seven patients had bridging callus at ≥1 cortex on the three-dimensional reconstruction; when present all united. Compared to radiographs, no bridging callus was present in any patient. Of the three patients lacking sonographic bridging callus, one went onto a nonunion (77.8%-sensitive and 100%-specific to predict union). At twelve weeks, nine patients had bridging callus at ≥1 cortex on three-dimensional reconstruction and all united (100%-sensitive and 100%-specific to predict union). Compared to radiographs, seven of the nine patients that united had bridging callus. Three-dimensional reconstruction of the anteromedial and anterolateral tibial surface was achieved in all patients, and detection of sonographic bridging callus on the three-dimensional reconstruction demonstrated substantial inter-observer agreement (kappa=0.78, 95% confidence interval 0.29–1.0, p=0.011). Conclusions. Three-dimensional fracture reconstruction can be created using multiple ultrasound images in order to evaluate the presence of bridging callus. This imaging modality has the potential to identify impaired healing at an early stage in fracture management. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Three-dimensional (3D) printing has become more frequently used in surgical specialties in recent years. Orthopaedic surgery is particularly well-suited to 3D printing applications, and thus has seen a variety of uses for this technology. These uses include pre-operative planning, patient-specific instrumentation (PSI), and patient-specific implant production. As with any new technology, it is important to assess the clinical impact, if any, of three-dimensional printing. The purpose of this review was to answer the following questions: . What are the current clinical uses of 3D printing in orthopaedic surgery?. Does the use of 3D printing have an effect on peri-operative outcomes?. Four electronic databases (Embase, MEDLINE, PubMed, Web of Science) were searched for Articles discussing clinical applications of 3D printing in orthopaedics up to November 13, 2018. Titles, abstracts, and full texts were screened in duplicate and data was abstracted. Descriptive analysis was performed for all studies. A meta-analysis was performed among eligible studies to compare estimated blood loss (EBL), operative time, and fluoroscopy use between 3D printing cases and controls. Study quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) criteria for non-randomized studies and the Cochrane Risk of Bias Tool for randomized controlled trials (RCTs). This review was prospectively registered on PROSPERO (Registration ID: CRD42018099144). One-hundred and eight studies were included, published between 2012 and 2018. A total of 2328 patients were included in these studies, and 1558 patients were treated using 3D printing technology. The mean age of patients, where reported, was 47 years old (range 3 to 90). Three-dimensional printing was most commonly reported in trauma (N = 41) and oncology (N = 22). Pre-operative planning was the most common use of 3D printing (N = 63), followed by final implants (N = 32) and PSI (N = 22). Titanium was the most commonly used 3D printing material (16 studies, 27.1%). A wide range of costs were reported for 3D printing applications, ranging from “less than $10” to $20,000. The mean MINORS score for non-randomized studies was 8.3/16 for non-comparative studies (N = 78), and 17.7/24 for non-randomized comparative studies (N = 19). Among RCTs, the most commonly identified sources of bias were for performance and detection biases. Three-dimensional printing resulted in a statistically significant decrease in mean operative time (−15.6 mins, p < .00001), mean EBL (−35.9 mL, p<.00001), and mean fluoroscopy shots (−3.5 shots, p < .00001) in 3D printing patients compared to controls. The uses of 3D printing in orthopaedic surgery are growing rapidly, with its use being most common in trauma and oncology. Pre-operative planning is the most common use of 3D printing in orthopaedics. The use of 3D printing significantly reduces EBL, operative time, and fluoroscopy use compared to controls. Future research is needed to confirm and clarify the magnitude of these effects

Background. There is no consensus on which glenoid plane should be used in total shoulder arthroplasty. Nevertheless, anatomical reconstruction of this plane is imperative for the success of a total shoulder arthroplasty. Methods. Three-dimensional reconstruction CT-scans were performed on 152 healthy shoulders. Four different glenoid planes, each determined by three surgical accessible bony reference points, are determined. The first two are triangular planes, defined by the most anterior and posterior point of the glenoid and respectively the most inferior point for the Saller's Inferior plane and the most superior point for the Saller's Superior plane. The third plane is formed by the best fitting circle of the superior tubercle and the most anterior and posterior point at the distal third of the glenoid (Circular Max). The fourth plane is formed by the best fitting circle of three points at the rim of the inferior quadrants of the glenoid (Circular Inferior). We hypothesized that the plane with normally distributed parameters, narrowest variability and best reproducibility would be the most suitable surgical glenoid plane. Results. No difference in position of the mean humeral center of rotation is found between the Circular Max and Circular Inferior plane (X=91.71degrees/X=91.66degrees p=0.907 and Y=90.83degrees /Y=91.7degrees p=0.054 respectively), while clear deviations are found for the Saller's Inferior and Saller's Superior plane (p < 0.001). The Circular Inferior plane has the lowest variability to the coronal scapular plane (p<0.001). Conclusion. This study provides arguments to use the Circular Inferior glenoid plane as preferred surgical plane of the glenoid. Level of evidence: Level II, Basic Science Study, Anatomical Survey

Sonographic callus may enable assessment of fracture healing. The aim of this study was to establish a reliable method for three-dimensional reconstruction of sonographic callus. Patients that underwent non-operative management of displaced midshaft clavicle fractures and intramedullary nailing of tibia fractures were prospectively recruited and followed to union. Ultrasound scanning was performed at periodical time points following injury. Infra-red tracking technology was used to map each image to a three-dimensional lattice. Criteria was fist established for two-dimensional bridging callus detection in a pilot study. Using echo intensity of the ultrasound image, semi-automated mapping was used to create an anatomic three-dimensional representation of fracture healing. Agreement on the presence of sonographic bridging callus was assessed using the kappa coefficient and intra-class-correlation (ICC) between observers. 112 clavicle fractures and 10 tibia fractures completed follow-up at six months. Sonographic bridging callus was detected in 62.5% (n=70/112) of the clavicles at six weeks post-injury. If present, union occurred in 98.6% of the fractures (n=69/70). If absent, nonunion developed in 40.5% of cases (n=17/42)(73.4%-sensitive and 100%-specific to predict union). Out of 10 tibia fractures, 7 had bridging callus of at least one cortex at 6 weeks and when present all united. Of the three patients lacking sonographic bridging callus, one went onto a nonunion (77.8%-sensitive and 100%-specific to predict union). The ICC for sonographic callus between four reviewers was 0.82 (95% CI 0.68–0.91). Three-dimensional ultrasound reconstruction of bridging callus has the potential to identify impaired fracture healing at an early stage in fracture management

Total temporomandibular joint (TMJ) replacements reduce pain and improve quality of life in patients suffering from end-stage TMJ disorders, such as osteoarthritis and trauma. Jaw kinematics measurements following TMJ arthroplasty provide a basis for evaluating implant performance and jaw function. The aim of this study is to provide the first measurements of three-dimensional kinematics of the jaw in patients following unilateral and bilateral prosthetic TMJ surgeries. Jaw motion tracking experiments were performed on 7 healthy control participants, 3 unilateral and 1 bilateral TMJ replacement patients. Custom-made mouthpieces were manufactured for each participant's mandibular and maxillary teeth, with each supporting three retroreflective markers anterior to the participant's lip line. Participants performed 15 trials each of maximum jaw opening, lateral and protrusive movements. Marker trajectories were simultaneously measured using an optoelectronic tracking system. Laser scans taken of each dental plate, together with CT scans of each patient, were used to register the plate position to each participant's jaw geometry, allowing 3D condylar motion to be quantified from the marker trajectories. The maximum mouth opening capacity of joint replacement patients was comparable to healthy controls with average incisal inferior translations of 37.5mm, 38.4mm and 33.6mm for the controls, unilateral and bilateral joint replacement patients respectively. During mouth opening the maximum anterior translation of prosthetic condyles was 2.4mm, compared to 10.6mm for controls. Prosthetic condyles had limited anterior motion compared to natural condyles, in unilateral patients this resulted in asymmetric opening and protrusive movements and the capacity to laterally move their jaw towards their pathological side only. For the bilateral patient, protrusive and lateral jaw movement capacity was minimal. Total TMJ replacement surgery facilitates normal mouth opening capacity and lateral and inferior condylar movements but limits anterior condylar motion. This study provides future direction for TMJ implant design

Abstract. OBJECTIVES. An unresolved challenge in osteoarthritis research is characterising the localised intra-tissue mechanical response of articular cartilage. The aim of this study was to explore whether laboratory micro-computed tomography (micro-CT) and digital volume correlation (DVC) permit non-destructive visualisation of three-dimensional (3D) strain fields in human articular cartilage. METHODS. Human articular cartilage specimens were harvested from the knee (n=4 specimens from 2 doners), mounted into a loading device and imaged in the loaded and unloaded state using a micro-CT scanner. Strain was calculated throughout the volume of the cartilage using the CT image data. RESULTS. Strain was calculated in the 3D volume with a spatial resolution of 75 µm, and the volumetric DVC calculated strain was within 5% of the known applied stain. Variation in strain distribution between the superficial, middle and deep zones was observed, consistent with the different architecture of the material in these locations. CONCLUSIONS. The DVC method is suitable for calculating strain in human articular cartilage. This method will be useful to generate chondral repair scaffolds that that seek to replicate the strain gradient in cartilage. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Background. The femoral head center shift on reduction time in total hip arthroplasty (THA) causes alteration of the muscle tension around the hip joint. Many studies about the shift of the femoral head in the cranio-caudal direction or medio-lateral direction on coronal plane have been reported. It has been known widely that the shift on these directions influence tension of the abductor muscle around the hip joint. Nevertheless few studies about the three-dimensional shift including the antero-posterior direction have been reported. Purpose. The purpose of this study is to evaluate the three-dimensional shift of the femoral head center in THA using three-dimensional THA templating software. Subjects & Methods. The subjects of this study were 156 primary THA cases of 143 patients. Using CT-based three-dimensional THA templating software ZedHip® (LEXI, Tokyo Japan), simulation of optimal implantation was performed on each THA case. On case which has over anteverted or less anteverted femoral neck, a stem which has modular neck system was selected to adjust anteversion of the femoral neck. The three-dimensional shift of the femoral head center on reduction time was calculated with ZedHip®. The three-dimensional shift was resolve into cranio-caudal, medio-lateral and antero-posterior direction (Fig. 1). Furthermore the correlation between the amount of the shift and hip joint deformity was investigated. Results. The average amount of the shift on cranio-caudal direction was 9.9mm to caudal side, on medio-lateral direction was 3.1mm to medial side and on antero-posterior direction was 2.6mm to posterior side. The average total amount of three-dimensional shift was 12.9mm (Fig. 2). On Crowe type 1 hips in 88 cases, the average shift to posterior side was 3.2mm, on Crowe type 2 in 20 cases was 3.7mm and on Crowe type 3 in 13 cases was 4.0mm. Among them there was no significant difference (Fig. 3). Conclusion. At THA surgery, the femoral head center shifted three-dimensionally and the maximum amount of shift on antero-posterior direction was 16.6mm to posterior side. There was no correlation between these amounts of the shift on antero-posterior direction and anatomical deformity of the hip joint. It is important to understand the shift of the femoral head center for predicting the alteration of muscle tension around the hip joint. The shift on antero-posterior direction influences the tension of iliopsoas muscle and there is a possibility that the shift to posterior side causes anterior iliopsoas impingement after THA surgery

Objective. In total knee arthroplasty, three-dimensional “criss-cross” line locate femoral osteotomy and conventional osteotomy were used. By comparing the two methods osteotomy in patients before and after surgery and imaging-related information data, to evaluate the recent post operative efficacy, at the same time to find out if there has clinical evidence that three-dimensional “criss-cross” line locate femoral osteotomy can be used in total knee arthroplasty. Methods. From July 2012 to July 2014, 64 patients who undertook the artificial total knee arthroplasty were divided into 2 groups: conventional osteotomy group(group A)and three-dimensional “criss-cross” line locate femoral osteotomy group(group B). In the X-ray of the two groups, it was measured that the hip-knee-ankle angle and the joint gap symmetry of 90°flexion degree. It was also measured that the two group joints range of motion. Those data were statistically analyzed. The KSS score of the two groups were compared. Results. In Group B the excellent and good rate was 93.8%, and Group A was 81.3%. The postoperative results of Group A were relatively better than Group B in limb alignment and joint mobility. There were significant differences between the prosthesis placement of the two group patients. Conclusion. The Short-term results of the three-dimensional “criss-cross” line locate femoral osteotomy group was better than the conventional osteotomy group. The reference osteotomy method of three-dimensional “criss-cross” line is very helpful to have a good result in TKA

This paper describes how advances in three-dimensional printing may benefit the military trauma patient, both deployed on operations and in the firm base. Use of rapid prototype manufacturing to produce a 3D representation of complex fractures that can be held and rotated will aid surgical planning within multidisciplinary teams. Patient-clinician interaction can also be aided using these graspable models. The education of military surgeons could improve with the subsequent accurate, inexpensive models for anatomy and surgical technique instruction. The developing sphere of additive manufacturing (3D printing functional end-use components) lends itself to further advantages for the military orthopaedic surgeon. Military trauma patients could benefit from advances in direct metal laser sintering which enable the manufacture of complex surfaces and porous structures on bio-metallic implants not possible using conventional manufacturing. “Bio-printing” of tissues mimicking anatomical structures has potential for military trauma patients with bone defects. Deployed surgeons operating on less familiar fracture sites could benefit from three-dimensionally printing patient-specific medical devices. These can make operating technically easier, reducing radiation exposure and operating time. Further ahead, it may be possible to contemporaneously 3D print medical devices unavailable from the logistics chain whilst operating in the deployed environment

We report the case of a 12-year-old boy with flexion loss in the left elbow caused by deficient of the concavity corresponding to the coronoid fossa in the distal humerus. The range of motion (ROM) was 15°/100°, and pain was induced by passive terminal flexion. Plain radiographs revealed complete epiphyseal closure, and computed tomography (CT) revealed a flat anterior surface of the distal humerus; the coronoid fossa was absent. Then, the bony morphometric contour was surgically recreated using a navigation system and a three-dimensional elbow joint model. A three-dimensional model of the elbow joint was made preoperatively and the model comprising the distal humerus was milled so that elbow flexion flexion of more than 140° could be achieved against the proximal ulna and radius. Navigation-assisted surgery (contouring arthroplasty) was performed using CT data from this milled three-dimensional model. Subsequently, an intraoperative passive elbow flexion of 135° was obtained. However, active elbow flexion was still inadequate one year after operation, and a triceps lengthening procedure was performed. At the final follow-up one year after triceps lengthening, a considerable improvement in flexion was observed with a ROM of −12°/125°. Plain radiographs revealed no signs of degenerative change, and CT revealed the formation of the radial and coronoid fossae on the anterior surface of the distal humerus. Navigation-assisted surgery for deformity of the distal humerus based on a contoured three-dimensional model is extremely effective as it facilitates evaluation of the bony morphometry of the distal humerus. It is particularly useful as an indicator for milling the actual bone when a model of the mirror image of the unaffected side cannot be applied to the affected side as observed in our case

Summary Statement. We used three-dimensional software to assess different anatomic variables in the femur. The canal of Femur twisted slightly below the lesser trochanter in cases with a larger angle of anteversion. Introduction. Accurate positioning of the joint prosthesis is essential for successful total hip arthroplasty (THA). To aid in tailoring of the prosthesis, we used three-dimensional software to assess different anatomic variables in the femur. Patients & Methods. We used CT imaging data of the unaffected normal side of the 25 patients (22 females, age range 30 to 81 years) who underwent THA in 2012 in our hospital. The femur was reconstructed from CT data and measured using three-dimensional modeling software (Mimics 16.0 Materialise, Leuven, Belgium). We measured ellipse fitting to the medullary canal in the axial plane of the femur at 20-mm intervals. The angle between the major axis of those ellipses and the axis of the femoral neck was measured and expressed as the canal rotation. The distance between the lesser trochanter and the center of the femoral head was measured along the Z axis. Results. The major axes of the ellipses direct to medial, front and medial side in the level of epiphysis, above isthmus and distal portion respectively in all cases. The maximum rotated level was above isthmus. The rotation angle in the proximal portion ranged from 36 to 84 degrees (mean, 60.6 degrees, SD ± 12.1). The rotation angle of the distal portion ranged from 71 to 95 degrees (mean, 86.1 degrees, SD ± 6.1). Discussion/Conclusion. The torsion of the canal varied more widely between individuals in the proximal portion than did the distal portion. In addition, the torsion of the proximal aspect, although more variable, was on average smaller when the angle of anteversion was large. Because the canal twisted slightly below the lesser trochanter in cases with a larger angle of anteversion, it is suggested that attention to the degree of anteversion of a flat prosthesis stem is warranted

Purpose: Scoliosis is a three-dimensional deformation of the spinal column. Modern surgical techniques have attempted to address this 3D component of the problem but pre- and postoperative measurements lack precision. A solution is stereoradiographic 3D reconstruction providing 1.1 mm precision for vertebral shape and 1.4° precision for axial rotation. Material and methods: Ten patients (seven adolescents and three adults) with idiopathic scoliosis (mean 56°, range 36°–78°) were treated with an in situ arching method. A calibrated teleradiogram (AP and lateral view) was obtained before and after surgery. The spinal columns were reconstructed by stereoradiography. Six rotation angles were measured in the three planes for each vertebra and each intervertebral space, taking into account the curvatures and their apical and junctional zones. Results: Preoperatively, for thoracic scoliosis, measurements were: mean vertebral axial rotation (VAR) measured at the apex = 20°; mean lateral axial rotation (LAR) of the junctional zones = 30°; mean intervertebral rotation (IVR) = 10°. Depending on the curvatures, in situ arching yielded a 52–60% correction of the VAR at the apex, and 78–79% correction of the junctional zones. VLR of the junctional zoenes was improved 58–74%. Intervertebral sagittal rotation (ISR) at the summit (kyphosis) was improved 5.5° on the average. Discussion: Unlike computed tomoraphy where scans are obtained in the supine position, three-dimensional reconstruction of the spinal column enables a precise analysis of the loaded spine. Improvement was significant in the frontal plane with 18.3° and 21.4° improvement of the VLR for the thoracic and thoracolumbar junctional zones respectively, compared with the rod rotation where the peroperative stereophotogram showed a 9.6° and 8.6° gain respectively. There was a real improvement in VAR, differing from the literature where the rotation of the rod appears to be less pronounced. Conclusion: Three-dimensional reconstruction of the spinal column enables a segmentary analysis of scoliosis deformations. In addition, by enabling a view of the spinal column in all directions, angle measurements can be made with precision allowing repeated measurements and comparisons. This technique demonstrated the efficacy of in situ arching in improving vertebral rotation

Introduction. Kinematically or anatomically aligned total knee arthroplasty (TKA) has been reported to provide improved clinical outcomes by replicating patient's original joint line [1][2]. It has been known that tibial (joint line) varus varies among patients, and the tibial varus would increase over progression of arthritis and bone remodeling. For those patients with significant deformity, the current tibial varus may significantly differ from its pre-diseased state. In this exploratory study, geometry and alignment of the tibial growth plate were measured with respect to tibial anatomical landmarks in order to better understand modes of tibial deformity and seek possible application in reconstructing pre-diseased joint alignment. Methods. CT scans of sixteen healthy Japanese knees (M6:F10, Age 31.9±13.9 years) were studied. Three-dimensional reconstruction models were created using Mimics 17 (Materialise, Leuven, Belgium). First, a mid-sagittal tibial reference plane, for comparing the varus/valgus orientation of the tibial plateau to that of the growth plate, was defined by the medial margin of the tibial tuberosity, origin of the PCL and center of the foot joint. The tibial plateau (or joint line plane) was determined from three points; dwell point of femur (aligned in extension) on lateral tibial articular surface, and two points at anterior and posterior rim of medial tibial articular surface sampled in the sagittal view and coinciding with dwell point of femur on medial tibia. Then, a three-dimensional model of the tibial growth plate was extracted using the Livewire function and mask editing tools in Mimics. To determine 3D orientation of the growth plate (GP), the vertical mass moment of inertia axis was calculated for the 3D model. The inertia axes were also determined for medial and lateral half of the GP (Figure 1). Results. Tibial plateau (TP) had 2.39±1.72 degrees of varus in coronal view and 11.12±3.90 degrees of posterior inclination in sagittal view. The shape of the GP is noticeably different between medial and lateral. The medial half tends to incline posteriorly towards medial, while the lateral half is twisted anteriorly. In coronal view, GP axis was in 1.27±1.49 degrees valgus to midsagittal plane. Normal axis of the TP was in varus to the GP axis by 3.66±1.79 degrees. The GP medial half was in 5.81±2.49 degrees valgus and 1.63±2.59 degrees anteriorly inclined with respect to the TP. The GP lateral half was in 11.65±2.07 degrees varus and 18.66±4.44 degrees anteriorly inclined relative to the TP. Discussion. The preliminary results from 16 healthy knees suggested that the tibial growth plate is aligned to midsagittal plane and tibial plateau in varus/valgus orientations with relatively small variations. More study samples will be required to validate usefulness of this method in surgical planning. Distinctive shape difference for medial and lateral half of the growth plate was also observed. Future study should also include diseased knees with various levels of deformities

Glenoid and humeral head bone defects have long been recognized as major determinants in recurrent shoulder instability as well as main predictors of outcomes after surgical stabilization. However, a universally accepted method to quantify them is not available yet. The purpose of the present study is to describe a new CT method to quantify bipolar bone defects volume on a virtually generated 3D model and to evaluate its reproducibility.

A cross-sectional observational study has been conducted. Forty CT scans of both shoulders were randomly selected from a series of exams previously acquired on patients affected by anterior shoulder instability. Inclusion criterion was unilateral anterior shoulder instability with at least one episode of dislocation. Exclusion criteria were: bilateral shoulder instability; posterior or multidirectional instability, previous fractures and/or surgery to both shoulders; congenital or acquired inflammatory, neurological, or degenerative diseases. For all patients, CT exams of both shoulders were acquired at the same time following a standardized imaging protocol. The CT data sets were analysed on a standard desktop PC using the software 3D Slicer. Computer-based reconstruction of the Hill-Sachs and glenoid bone defect were performed through Boolean subtraction of the affected side from the contralateral one, resulting in a virtually generated bone fragment accurately fitting the defect. The volume of the bone fragments was then calculated. All measurements were conducted by two fellowship-trained orthopaedic shoulder surgeons. Each measurement was performed twice by one observer to assess intra-observer reliability. Inter and intra-observer reliability were calculated. Intraclass Correlation Coefficients (ICC) were calculated using a two-way random effect model and evaluation of absolute agreement. Confidence intervals (CI) were calculated at 95% confidence level for reliability coefficients. Reliability values range from 0 (no agreement) to 1 (maximum agreement).

The study included 34 males and 6 females. Mean age (+ SD) of patients was 36.7 + 10.10 years (range: 25 – 73 years). A bipolar bone defect was observed in all cases. Reliability of humeral head bone fragment measurements showed excellent intra-observer agreement (ICC: 0.92, CI 95%: 0.85 – 0.96) and very good interobserver agreement (ICC: 0.89, CI 95%: 0.80 – 0.94). Similarly, glenoid bone loss measurement resulted in excellent intra-observer reliability (ICC: 0.92, CI 95%: 0.85 – 0.96) and very good inter-observer agreement (ICC: 0.84, CI 95%:0.72 – 0.91).

In conclusion, matching affected and intact contralateral humeral head and glenoid by reconstruction on a computer-based virtual model allows identification of bipolar bone defects and enables quantitative determination of bone loss.

Introduction:. For 30 years, uncemented anatomic hip stems have been implanted with documented clinical results[1,2]. Their geometry can be linked back to the geometry of the PCA and ABG stems. Modifications to date include stem length, body geometry, material, and reduction in distal geometry. New tools have been developed allowing anatomical measurements and analysis of three-dimensional digital femora geometry through CT scans[3]. The purpose of this study is to analyze three-dimensional contact of various anatomic hip stem designs using this technique. Methods:. Six femora (57–87 yrs, 72–88 kg), were selected from a CT scan database (SOMA™) of 604 Caucasian bones. They were selected based on femoral anteversion (average +/−1.5 * std. dev.) with three measuring[4] 8–10° and three 31–33° of anteversion. The CT scans were segmented into cancellous/cortical bone and converted into CAD models in PRO/Engineer Wildfire (v.5). A/P views of the bones were scaled to a 120% magnification to allow three surgeons to surgically template and choose the stem size and location (maximizing fill (n = 1); restoring the head center (n = 2)) with two implant designs (1-Citation TMZF and 2-ABG II Monolithic, Stryker Orthopaedics, Mahwah). Measurements from templating were used to virtually implant CAD models of the implants into the bones (n = 36 bone/stem assemblies). The assemblies were imported into Geomagic Qualify 2012 for 3D deviation analysis comparing the coated region of the implant to the cortical-cancellous boundary. The analysis generated color map profiles based on the following categories: Contact (−2.0 to 0.5 mm), Conformity (0.5 to 2.0 mm), Proximity (2.0 to 5.0 mm), and Gap (5.0 to 12 mm) and the percent of the surface that was within each of these categories. These results were compared for patterns within and across the anatomic families. Results:. Similar patterns of fit were observed within and across both families. The same size implants were not always used together across both systems. The strongest commonality was found regarding the percentage of the implant adjacent to more than 5 mm of cancellous bone (Gap, shown in red in Figure 1b) and the pattern of contact on the medial curvature of the implants. On average 61% and 56% of the metaphyseal region of Implants 1 and 2, respectively, is adjacent to 5–12 mm of cancellous bone between the implant and cortical bone. Implants 1 and 2 also demonstrated 30% and 37% between 0.5 and 5 mm of cancellous bone to the cortical boundary. Contact (< .5 mm) was only achieved in areas where bone would have been removed through femoral preparation. When maximizing fill, it was found that the percent Gap was reduced and distributed between conformity and proximity. There was also less variability between both systems when the goal was to maximize fill, however there was no statistical difference given the sample size between both stems regardless of method. Discussion:. Proper load transfer is essential for positive bone remodeling for short/long term fixation. As anatomic stems load femurs circumferentially, it is important to note that common characteristics transfer load to bone potentially contributing to their success. Previously, technology has not permitted circumferential analysis of implant fit on a wide scale, reproducible basis

Introduction:. The widespread use of TKA promoted studies on kinematics after TKA, particularly of the femorotibial joint. Knee joint kinematics after TKA, including the range of motion (ROM) and the physical performance, are also influenced by the biomechanical properties of the patella. Surgeons sometimes report complications after TKA involvinganterior knee pain, patellofemoral impingement and instability. However, only few studies have focused specially on the patella. Because the patella bone is small and overlapped with the femoral component on scan images. In addition, the patellar component in TKA is made of x-ray–permeable ultra-high molecular weight polyethylene. It is impossible to radiographically determine the external contour of the patellar component precisely. No methods have been established to date to track the dynamic in vivo trajectory of the patella component. In this study, we analyzed the in vivo three-dimensional kinematics of the patellar component in TKA by applying our image matching method with image correlations. Methods:. A computed tomography (CT) and an x-ray flat panel detector system (FPD) were used. FPD-derived post-TKA x-ray images of the residual patellar bone were matched by computer simulation with the virtual simulation images created using pre-TKA CT data. For the anatomic location of the patellar component, the positions of the holes drilled for the patellar component pegs were used. This study included three patients with a mean age of 68 years (three females with right knee replacement) who had undergone TKA with the Quest Knee System and achieved a mean passive ROM of 0 to ≥ 130° after 6 or more month post-TKA. We investigated three-dimensional movements of the patellar component in six degrees of freedom (6 DOF) during squatting and kneeling. Furthermore, we simulated the three-dimensional movement of the patellar component, and we estimated and visualized the contact points between the patellar and femoral components on a three-dimensional model. Results:. Average root mean square errors of this technique with the patellar bone of a fresh-frozen pig complete knee joint have been confirmed as 0.2 mm for the translations and 0.2 degrees for the rotation. The 6 DOF analysis results showed that patellar dynamics were similar for all subjects on squatting and kneeling. For the patellar rotation during squatting, only 1 to 2 additional degrees were noted for all subjects. During kneeling, the patellar rotation noted adduction for all subjects. The patellar contact point on the femoral component gradually showed superior shift, increasing the distance with knee flexion during squatting and kneeling (Fig, 1. 2). Discussions and Conclusions:. In this study, no patellar shifts were detected in rotation or tilt during squatting, suggesting that the patellar component remained in the positions designed for early stages of flexion. And the patellar component shifted towards the lateral side during squatting. This finding suggests the idea that the patellar movement reflected the design of the Quest Knee system. This study demonstrated that the analytical method is useful for evaluating the pathologies and post-surgical conditions of the knee and other joints

The purpose of this study is to investigate the three-dimensional (3D) kinematics of normal knees in deep knee-bending motions like squatting and kneeling. Material & Methods: We investigated the in vivo kinematics of 4 Japanese healthy male volunteers (8 normal knees in squatting, 7 normal knees in kneeling). Each sequential motion was performed under fluoroscopic surveillance in the sagittal plane. Femorotibial motion was analyzed using 2D/3D registration technique, which uses computer-assisted design (CAD) models to reproduce the spatial position of the femur and tibia from single-view fluoroscopic images. We evaluated the femoral rotation relative to the tibia and anteroposterior (AP) translation of the femoral sulcus and lateral epicondyle on the plane perpendicular to the tibial mechanical axis. Student's t test was used to analyze differences in the absolute value of axial rotation and AP translation of the femoral sulcus and lateral epicondyle during squatting and kneeling. Values of P < 0.05 were considered statistically significant. During squatting, knees were gradually flexed from −2.8 ± 1.3° to 145.5 ± 5.1° on average. Knees were gradually flexed from 100.8 ± 3.9° to 155.6 ± 3.2° on average during kneeling. Femurs during squatting displayed sharp external rotation relative to the tibia from 0° to 30° of flexion and it reached 12.5 ± 3.3° on average. From 30° to 130° of flexion, the femoral external rotation showed gradually, and it reached 19.1 ± 7.3° on average. From 130° to 140° of flexion, it was observed additionally, and reached 22.4 ± 6.1° on average. All kneeling knees displayed femoral external rotation relative to the tibia sharply from 100° to 150° of flexion, and it reached 20.7 ± 7.5° on average. From 100° to 120° of flexion, the femoral external rotation during squatting was larger than that during kneeling significantly. From 120° to 140° of flexion, there was no significant difference between squatting and kneeling. The sulcus during squatting moved 4.1 ± 4.8 mm anterior from 0° to 60° of flexion. From 60° of flexion it moved 13.6 ± 13.4 mm posterior. The sulcus during kneeling was not indicated significant movement with the knee flexion. The lateral epicondyle during squatting moved 39.4 ± 7.7 mm posterior from 0° to 140° of flexion. The lateral epicondyle during kneeling moved 22.0 ± 5.4 mm posterior movement from 100° to 150° of flexion. In AP translation of the sulcus from 100° to 140° of flexion, there was no significant difference between squatting and kneeling. However in that of the lateral epicondyle, squatting groups moved posterior significantly. Even if they were same deep knee-bending, the kinematics were different because of the differences of daily motions. The results in this study demonstrated that in vivo kinematics of deep knee-bending were different between squatting and kneeling

Purpose. The purpose of this study was to assess the accuracy of three-dimensional camera technology when monitoring deformity correction by an Ilizarov frame and to compare it to manual measurements. Methods and Results. A model consisting of an Ilizarov frame built around an artificial tibia and fibula was used with retro-reflective markers placed on the frame and bones to allow for the positions of each to be detected by the camera system. Measurements made by the camera system were compared to measurements taken manually. In the assessment of frame lengthening, the camera system average error was 2% (SD 2%) compared to 7% (SD 6%) for manual measurement. In the assessment of bone lengthening, the camera system average error was 4% (SD 4%) compared to 34% (SD 8%) for manual measurement. The technology also demonstrated good accuracy in the measurement of angular deformity changes. Conclusion. The results of this study demonstrate that the measurement of deformity correction with three-dimensional infra-red camera technology is superior to manual measurements in a model of deformity correction. This method could replace or greatly reduce x-ray exposure in monitoring deformity correction post-operatively

During total knee replacement (TKR), knee surgical navigation systems (KSNS) report in real time relative motion data between the tibia and the femur from the patient under anaesthesia, in order to identify best possible locations for the corresponding prosthesis components. These systems are meant to support the surgeon for achieving the best possible replication of natural knee motion, compatible with the prosthesis design and the joint status, in the hope that this kinematics under passive condition will be then the same during the daily living activities of the patient. Particularly, by means of KSNS, knee kinematics is tracked in the original arthritic joint at the beginning of the operation, intra-operatively after adjustments of bone cuts and trial components implantation, and after final components implantation and cementation. Rarely the extent to which the kinematics in the latter condition is then replicated during activity is analysed. As for the assessment of the active motion performance, the most accurate technique for the in-vivo measurements of replaced joint kinematics is three-dimensional video-fluoroscopy. This allows joint motion tracking under typical movements and loads of daily living. The general aim of this study is assessing the capability of the current KSNS to predict replaced joint motion after TKR. Particularly, the specific objective is to compare, for a number of patients implanted with two different TKR prosthesis component designs, knee kinematics obtained intra-operatively after final component implantation measured by means of KSNS with that assessed post-operatively at the follow-up by means of three-dimensional video-fluoroscopy. Thirty-one patients affected by primary gonarthrosis were implanted with a fixed bearing posterior-stabilized TKR design, either the Journey® (JOU; Smith&Nephew, London, UK) or the NRG® (Stryker®-Orthopaedics, Mahwah, NJ-USA). All implantations were performed by means of a KSNS (Stryker®-Leibinger, Freiburg, Germany), utilised to track and store joint kinematics intra-operatively immediately after final component implantation (INTRA-OP). Six months after TKR, the patients were followed for clinical assessment and three-dimensional video fluoroscopy (POST-OP). Fifteen of these patients, 8 with the JOU and 7 with the NRG, gave informed consent and these were analyzed. At surgery (INTRA-OP), a spatial tracker of the navigation system was attached through two bi-cortical 3 mm thick Kirschner wires to the distal femur and another to the proximal tibia. The conventional navigation procedure recommended in the system manual was performed to calculate the preoperative deformity including the preoperative lower limb alignment, to perform the femoral and tibial bone cuts, and to measure the final lower limb alignment. All these assessment were calculated with respect to the initial anatomical survey, the latter being based on calibrations of anatomical landmarks by an instrumented pointer. Patients were then analysed (POST-OP) by three-dimensional video-fluoroscopy (digital remote-controlled diagnostic Alpha90SX16; CAT Medical System, Rome-Italy) at 10 frames per second during chair rising-sitting, stair climbing, and step up-down. A technique based on CAD-model shape matching was utilised for obtaining three-dimensional pose of the prosthesis components. Between the two techniques, the kinematics variables analysed for the comparison were the three components of the joint rotation (being the relative motion between the tibial and femoral components represented using a standard joint convention, the translation of the line through the medial and lateral contact points (being these points assumed to be where the minimum distance between the femoral condyles and the tibial baseplate is observed) on the tibial baseplate and the corresponding pivot point, and the location of the instantaneous helical axes with the corresponding mean helical axis and pivot point. In all patients and in both conditions, physiological ranges of flexion (from −5° to 120°), and ab-adduction (±5°) were observed. Internal-external rotation patterns are different between the two prostheses, with a more central pivoting in NRG and medial pivoting in JOU, as expected by the design. Restoration of knee joint normal kinematics was demonstrated also by the coupling of the internal rotation with flexion, as well as by the roll-back and screw-home mechanisms, observed somehow both in INTRA- and POST-OP measurements. Location of the mean helical axis and pivot point, both from the contact lines and helical axes, were very consistent over time, i.e. after six months from intervention and in fully different conditions. Only one JOU and one NRG patient had the pivot point location POST-OP different from that INTRA-OP, despite cases of paradoxical translation. In all TKR knees analysed, a good restoration of normal joint motion was observed, both during operation and at the follow-up. This supports the general efficacy of the surgery and of both prosthesis designs. Particularly, the results here reported show a good consistency of the measurements over time, no matter these were taken in very different joint conditions and by means of very different techniques. Intra-operative kinematics therefore does matter, and must be taken into careful consideration for the implantation of the prosthesis components. Joint kinematics should be tracked accurately during TKR surgery, and for this purpose KSNS seem to offer a very good support. These systems not only supports in real time the best possible alignment of the prosthesis components, but also make a reliable prediction of the motion performance of the replaced joint. Additional analyses will be necessary to support this with a statistical power, and to identify the most predicting parameters among the many kinematics variables here analysed preliminarily

Introduction and Aims: There is a relationship between the anatomy of the hip joint and the development of arthritis. A common cause of hip pain in the young adult that can lead to arthritis is acetabular dysplasia. More recently, femoroacetabular impingement has been described as another cause of hip pain. The purpose of our study was to evaluate the applicability of pelvic computed tomography (CT) with three-dimensional surface rendering to evaluate femoro-acetabular impingement. Method Thirty-six hips (30 patients; 17 males; 13 females) with persistent hip pain, mean age 41 (37–52), underwent three-dimensional CT of the pelvis, as well as MRI arthrography with gadolinium enhancement. On 3D CT, the concavity of the femoral head-neck junction (offset), alpha angle as described by Notzli was calculated to depict the anterior femoral neck contour. The concavity of the posterior aspect of the head neck junction was measured as the beta angle. The same measurements were made in 20 hips, consisting of randomly selected patients with no prior history of hip pathology or pain (mean age 37; 13 males; eight females). Results The mean alpha angle for the symptomatic group was 66.4 (39–94) and 43.8 (39.3–48.3) for the control group (p=0.001). All symptomatic hips had abnormal findings on MRA: labral tears in all; cartilage delamination/ulceration in 14 hips; herniation pits in six hips. The majority of labral tears and delamination were located in the antero-superior quadrant. In the surgical treated group, all MRA findings were confirmed. The mean beta angle was significantly smaller (increase concavity) in the symptomatic versus the controls: 40.2 versus 43.8 (p=0.011). Interestingly in the symptomatic group the beta angle was significantly lower than the alpha angle (p< 0.02), but not in the controls. Conclusion: 3D CT with surface rendering and multiplanar reformation is useful to determine degree of bone buttressing of the anterior femoral head-neck junction quantitatively assessed by alpha angle measurement, which is elevated in patients with femoro-acetabular impingement. With a greater posterior concavity i.e. small beta angle in the symptomatic group versus the control, subclinical slipped femoral epiphysis remains a plausible cause of this deformity