Acromioclavicular joint injuries are one of the most common injuries in the shoulder girdle complex. Surgical management is considered based on patient profile, level of activity, pain, and classification of injury. To date, a vast array of surgical techniques have been proposed and described in the literature, a possible reason being that the optimal solution is still uncertain. The aim of this study is to determine the efficacy of an alternative surgical technique. This study is a retrospective case series of 80 patients that have been operated by a single surgeon over a period of 6 years. A novel surgical technique, the ‘BiPOD method’, was applied where a synthetic artificial ligament (LARS®) is used to reconstruct and reduce the acromioclavicular joint. The technique is done in a reproducible manner, where a single continuous artificial ligament is used to reduce and reconstruct both, the coracoclavicular and acromioclavicular ligament complexes to achieve bidirectional stability. Patients were followed-up postoperatively, either clinically where possible or telephonically. The Acromioclavicular Joint Instability Score (ACJI) and radiographic measurements were used to determine the clinical and surgical outcome of the surgery. Radiographic parameters, measuring the reduction of the coracoclavicular- and acromioclavicular joint, were analysed and documented. The results showed marked improvement in both, the coracoclavicular distance and acromioclavicular distance. Clinically, using the ACJI scoring system, the patients reported substantial improvement in pain and function. Complications were recorded but were insignificant. The BiPOD surgical technique, making use of an artificial LARS® ligament, has proven acceptable outcomes in the surgical management of acromioclavicular joint dislocations

Preoperative talar valgus deformity increases the technical difficulty of total ankle replacement (TAR) and is associated with an increased failure rate. Deformity of ≥15° has been reported to be a contraindication to arthroplasty. The goal of the present study was to determine whether the operative procedures and clinical outcomes of TAR for treatment of end-stage ankle arthritis were comparable for patients with preoperative talar valgus deformity of ≥15° as compared to those with <15°. We will describe the evolving surgical technique being utilized to tackle these challenging cases. Fifty ankles with preoperative coronal-plane tibiotalar valgus deformity of ≥15° “valgus” group) and 50 ankles with valgus deformity of <15° (“control” group) underwent TAR. The cohorts were similar with respect to demographics and components used. All TARs were performed by a single surgeon. The mean duration of clinical follow-up was 5.5 years (minimum two years). Preoperative and postoperative radiographic measurements of coronal-plane deformity, Ankle Osteoarthritis Scale (AOS) scores and Short Form (SF)-36 scores were prospectively recorded. All ancillary (intraoperative) and secondary procedures, complications and measurements were collected. The AOS pain and disability subscale scores decreased significantly in both groups. The improvement in AOS and SF-36 scores did not differ significantly between the groups at the time of the final follow-up. The valgus group underwent more ancillary procedures during the index surgery (80% vs 26%). Tibio-talar deformity improved significantly toward a normal weight-bearing axis in the valgus group. Secondary postoperative procedures were more common in the valgus group (36%) than the controls (20%). Overall, re-operation was not associated with poorer patient outcome scores. Metal component revision surgery occurred in seven patients (three valgus and four controls). These revisions included two deep infections (2%), one in each group, which were converted to hindfoot fusions. Therefore, 94% of the valgus group retained their original components at final follow-up. Thus far, this is the largest reported study that specifically evaluates TAR with significant preoperative valgus alignment, in addition to having the longest follow-up. Satisfactory midterm results were achieved in patients with valgus mal-alignment of ≥15°. The valgus cohort required more procedures during and after their TAR, as well as receiving more novel techniques to balance their TAR. Whilst longer term studies are needed, valgus coronal-plane alignment of ≥15° should not be considered an absolute contraindication to TAR if the associated deformities are addressed

The best algorithm, measurements, and criteria for screening children with Down syndrome for upper cervical instability are controversial. Many authors have recommended obtaining flexion and extension views. We noted that patients who require surgical stabilization due to myelopathy or cord compression typically have grossly abnormal radiographic measurements on the neutral upright lateral cervical spine radiograph (NUL). This study was designed to determine whether a full series of cervical spine images including flexion/extension lateral radiographs (FEL) was important to avoid missing upper cervical instability. This is a retrospective evaluation of cervical spine images obtained between 2006 and 2012 for the purposes of “screening” children with Down syndrome for evidence of instability. The atlanto-dental interval, space available for cord, and basion axial interval were measured on all films. The Weisel-Rothman measurement was made in the FEL series. Clinical outcome of those with abnormal measurements were reviewed. Sensitivity, specificity, positive and negative predictive values of NUL and FEL x-rays for identifying clinically significant cervical spine instability were calculated. Two-hundred and forty cervical spine series in 213 patients with Down syndrome between the ages of four months and 25 years were reviewed. One hundred and seventy-two children had a NUL view, and 88 of these patients also had FEL views. Only one of 88 patients was found to have an abnormal ADI (≥6mm), SAC (≤14mm), or BAI (>12mm) on an FEL series that did not have an abnormal measurement on the NUL. This patient had no evidence of cord compression or myelopathy. Obtaining a single NUL x-ray is an efficient method for radiographic screening of cervical spine instability. Further evaluation may be required if abnormal measurements are identified on the NUL x-ray. We also propose new “normal” values for the common radiographic measurements used in assessing risk of cervical spine instability in patients with Down syndrome

Background:. Acetabular cup positioning. 1, 2. , leg length discrepancy. 3. and global offset. 4. are important parameters associated with outcomes following total hip arthroplasty (THA). Deviation from an accepted range of values for each of these parameters can lead to significant complications including nerve injury, low back pain, abnormal gait, increased dislocation rate, and bearing surface wear. The primary purpose of this study was to assess whether the use of the MAKO™ robotic hip system is reliable in predicting post-operative radiographic measurements of cup inclination, cup anteversion, leg length change, and global offset change in THA. Materials and Methods:. All robotic-assisted THAs performed using the MAKO™ system between June 2011 and Dec 2012 were reviewed. A single surgeon performed all cases through a mini-posterior approach. The intra-operative measurements of cup inclination and anteversion angles, leg length change, and global offset change recorded by the MAKO™ system were compared to the post-operative radiographic measurements. Results:. Sixty one cases met the inclusion and exclusion criteria. A strong inter- and intra-observer correlation was found for the radiographic measurements of cup inclination, cup anteversion, leg length discrepancy and global offset (r > 0.8 with p < 0.001 for all). Comparison between the MAKO™ and the radiographic measurements showed mean differences in inclination of 3.2° ± 2.7° (CI. 95. = 0.7), mean differences in anteversion of 3.8° ± 2.6° (CI. 95. = 0.7), mean differences in leg length change of 3.5 ± 2.6 mm (CI. 95. = 0.7), and mean differences in global offset change of 4.5 ± 3.7 mm (CI. 95. = 1.0). 85.2% of MAKO™-measured inclination angles were within 5° of radiographic measurements, and 96.7% within 10°. 65.6% of MAKO™-measured anteversion angles were within 5° of radiographic measurements, and 98.4% within 10° (Figure 1). 69.4% of MAKO™-measured leg length change measurements were within 5 mm of radiographic measurements, and 100% within 10 mm. 71.4% of MAKO™-measured global offset change measurements were within 5 mm of radiographic measurements, and 91.8% within 10 mm (Figure 2). Conclusion:. The MAKO™ robotic hip system showed good predictive value for cup inclination and anteversion angles, leg length change and femoral offset change measurements done post-operatively on plain radiographs. Further refinement of the MAKO™ system would be expected to make it more accurate in predicting the post-operative parameters mentioned

Multiple studies have shown that the symptomatology of knee osteoarthritis weakly correlate to radiographic severity of disease. Current literature however does not have much in the way of comparing functional outcomes of those with OA knees with radiographic severity. Our objective was to compare radiographic measurements of OA knees with self-reported functional outcomes and determine if radiographic severity of OA knees correlated with loss of functional ability. A retrospective review of prospectively collected registry data of 305 patients with osteoarthritis of the knee was collected. The patient's x-rays were reviewed, and radiographic measurements were taken to include medial, lateral and patellofemoral joint space distance measured in millimetres. The Kellgren and Lawrence, and Ahlback classifications of radiographic knee OA were computed. These were correlated with severity of functional limitations was measured using the SF36, Knee society score (KSS) and Oxford knee scores. Statistical analysis were conducted with SPSS V22.0 statistical software. Demographic characteristics and functional assessments were analysed using one way ANOVA test. Post-hoc test using Tukey HSD and effect size (partial-eta squared η. 2. ) was performed if one-way ANOVA was found to be statistically significant. A p-value of 0.05 or less was considered statistically significant. Pre-operative patient demographics are shown in table 1. Patients in with Grade 2 osteoarthritis were significantly younger than Grade 4 patients (post-hoc p=0.003). There were no statistically significant differences in age between the other Grades, and there were no differences in BMI or gender or operative site between all grades. There were significant differences in KSS Function scores between Grade 2 and Grade 3 patients (post-hoc p=0.017) and Grade 2 and 4 patients (post-hoc p < 0 .001). Statistically significant differences were also found between Grade 1 and Grade 4 patients for the KSS Knee score (post-hoc p=0.016). There were significant differences in Oxford knee score (post-hoc p=0.026) and SF- Physical Function (post-hoc p < 0 .001) between Grade 2 and Grade 4 patients too. The effect size η. 2. for KSS Function, KSS Knee and Oxford knee score was 0.05, 0.06 and 0.33 respectively. When comparing the loss of joint space with the functional scores, there were no statistically significant correlations. Our study show that the radiological severity of knee osteoarthritis based on the two scoring methods was able to correlate with worsening functional scores. Most notably, the differences in KSS function scores correlated strongly between Grade 2 and Grade 3 patients. Of note, there was no correlation between the loss of joint space and the severity of functional limitations across any of the scoring systems. Our study showed that although both the Kellgren and Lawrence and Ahlback radiological grading of Osteoarthritis were able to correlate with worsening functional scores, this was not due to loss of joint space alone and further studies need to be conducted on the other contributors to the scoring system such as osteophytes and subchondral sclerosis. Our study show that the radiological severity of knee osteoarthritis based on the two scoring methods was able to correlate with worsening functional scores. Most notably, the differences in KSS function scores correlated strongly between Grade 2 and Grade 3 patients. Of note, there was no correlation between the loss of joint space and the severity of functional limitations across any of the scoring systems. Our study showed that although both the Kellgren and Lawrence and Ahlback radiological grading of Osteoarthritis were able to correlate with worsening functional scores, this was not due to loss of joint space alone and further studies need to be conducted on the other contributors to the scoring system such as osteophytes and subchondral sclerosis. For any figures or tables, please contact authors directly

Introduction. Leg length and offset are important considerations in total hip arthroplasty (THA). Navigation systems are capable of providing intra-operative measurements of leg length and offset, and high accuracy has been shown in experimental studies. Objective. This in-vivo study assesses the accuracy of an imageless navigation system, with a pin-less femoral array, in measuring offset and leg length changes. Method. A prospective, consecutive series of 24 patients undergoing navigated total hip arthroplasty were included in the study. Intra-operative measurements of leg length and offset were recorded using the navigation system. For each patient pre- and post-operative digital radiographs were scaled and analysed to provide radiographic measurements of change in leg length and offset. Results. Measurements of leg length change made by the navigation system showed a statistically significant correlation with the size of change measured radiographically (R=.77, P < 0.0001). The mean difference between the radiographic and navigational measurement was 0.4 ± 2.8 mm. The navigation system was accurate to within 1 mm of the radiographic measurement in 50% of cases, within 2 mm in 67% of cases, and within 5 mm in 96% of cases. Measurements of offset change by the navigation system also showed a statistically significant correlation with radiographic measurements, however the correlation was less pronounced (R=.47, P=0.02). The mean difference between navigational and radiographic measurements was 1.4 ± 6.4 mm. The navigation system was accurate to within 1 mm of the radiographic measurement in 8% of cases, within 2 mm in 25% of cases, and within 5 mm in 75% of cases. Conclusion. This study demonstrates in-vivo that an imageless, non-invasive navigation system is a reliable tool for intra-operative leg length and offset measurement

Scoliosis is estimated to occur between 21–64% of patients with cerebral palsy (CP), where a subset of patients develops early onset scoliosis (EOS) before the age of ten. Traditional growth friendly (TGF) surgeries in the context of traditional growing rods have been shown to be effective in treating scoliosis in this population, however significant complication rates are reported. Currently, no studies have been done to examine the effect of novel growth friendly surgeries such as magnetically controlled growing rods (MCGR) on EOS in CP patients. The objective of this study is to compare MCGR with TGF surgeries in this patient population, specifically by evaluating radiographic measurements and risk of unplanned reoperations (UPRORs). Patients with EOS secondary to CP were prospectively identified from an international database, with data retrospectively analyzed. Scoliosis (primary curve), maximum kyphosis, T1-S1 and T1-T12 height were measured pre-operation, immediate post-operation, and at two-years follow-up. The risk and etiology of UPRORs were compared between MCGR and TGF. P < 0.05 was considered statistically significant for all analyses. Of the 120 patients that met inclusion criteria, 86 received TGF (age 7.5 ± 1.8 years; follow-up 7.0 ± 2.9 years) and 34 received MCGR (age 7.1 ± 2.2 years, follow-up 2.8 ± 0.5 years). Compared to TGF, MCGR resulted in significant improvements in maintenance of scoliosis correction (p=0.04). At final follow-up, UPRORs were 24% for MCGR (8/34 patients) and 43% (37/86 patients) for TGF (p=0.05). To minimize the influence of follow-up period, UPRORs within the first two years post-operation were evaluated: MCGR (21%, 7/34 patients) vs. TGF (14%, 12/86 patients; p=0.37). Within the first two years, etiology of UPROR as a percentage of all patients per group were deep infection (5% TGF, 6% MCGR), implant failure/migration (5% TGF, 9% MCGR), dehiscence (2% TGF, 3% MCGR), and superficial infection (1% TGF, 3% MCGR). The most common etiology of UPROR for TGF was deep infection and implant failure/migration and for MCGR was implant failure/migration. For patients with CP, at final follow-up, MCGR had superior maintenance of scoliosis correction; however, there was no difference in risk of UPROR within the first two years post-operatively (21% MCGR, 14% TGF)

We sought to validate a method of measuring the range of motion of knees on radiographs as part of a new system of “Virtual Knee Clinics”. The range of motion of 52 knees in 45 patients were first obtained clinically with goniometers and compared to radiographs of these patients' knees in full active flexion and extension. Four methods of plotting the range of motion on the radiographs were compared. The intra-class correlation coefficient (ICC) for inter-rater reliability using the goniometer was very high; ICC=0.90 in extension and 0.85 in flexion. The best ICC for radiographic measurement in extension was 0.86 indicating substantial agreement and best ICC in flexion was 0.95 (method 4). ICC for intra-rater reliability was 0.98 for extension and 0.99 for flexion on radiographic measurements. Measuring range of motion of the knee has never previously been validated in the literature. This study has allowed us to set up a “Virtual Knee Clinic,” combining postal questionnaires and radiographic measurements as a surrogate for knee function. We aim to maintain high quality patient surveillance following knee arthroplasty, reduce our new to follow-up ratios in line with Department of Health guidelines and improve patient satisfaction through reduced travel to hospital outpatients

Restoration of ankle alignment is thought to be critical in total ankle arthroplasty (TAA) outcomes, but previous research is primarily focused on coronal alignment. The purpose of this study was to investigate the sagittal alignment of the talar component. The talar component inclination, measured by the previously-described gamma angle, was hypothesized to be predictive of TAA outcomes. A retrospective review of the Canadian Orthopaedic Foot and Ankle Society (COFAS) database of ankle arthritis was performed on all TAA cases at a single center over a 11-year period utilizing one of two modern implant designs. Cases without postoperative x-rays taken between 6 and 12 weeks were excluded. The gamma angle was measured by two independent orthopaedic surgeons twice each and standard descriptive statistics was done in addition to a survival analysis. The postoperative gamma angles were analyzed against several definitions of TAA failure and patient-reported outcome measures from the COFAS database by an expert biostatistician. 109 TAA cases satisfied inclusion and exclusion criteria. An elevated postoperative gamma angle higher than 22 degrees was associated with talar component subsidence, defined as a change in gamma angle of 5 degrees or more between postoperative and last available followup radiographs. This finding was true when adjusting for age, gender, body mass index (BMI), and inflammatory arthritis status. All measured angles were found to have good inter- and intraobserver reliability. Surgeons should take care to not excessively dorsiflex the talar cuts during TAA surgery. The gamma angle is a simple and reliable radiographic measurement to predict long-term outcomes of TAA and can help surgeons counsel their patients postoperatively

INTRODUCTION. An accelerometer-based portable navigation system (KneeAlign2, OrthAlign Inc., Aliso Viejo, CA) is expected to improve mechanical axis and component alignment compared to conventional instrumentation in total knee arthroplasty (TKA). However, past reports have evaluated its accuracy using only radiographic measurements. The purpose of this study was to analyze the accuracy of the KneeAlign2 system with radiography and more detailed three-dimensional (3D) CT. METHODS. We targeted 22 patients (24 knees) with severe osteoarthritis who underwent primary TKA using the KneeAlign2 system. Cemented, fixed-bearing, cruciate-retaining prostheses were implanted in all patients. We used postoperative standing-position full-length radiographic evaluation of the lower limbs to measure the hip-knee-ankle angle (HKA), frontal femoral component angle (FFC), and frontal tibial component angle (FTC). However, lower limb rotation and knee flexion could affect radiographic measurement of HKA and the component positioning angle. We used 3D bone models reconstructed from pre- and postoperative CT images to precisely analyze the 3D component positioning. For a 3D matching bone model made from these models, a 2D projection of the pre- and postoperative component positioning planes was made, and the projection angle was measured as angle error compared to the preoperative planned position (Figure 1). Average surgery time and total blood loss on postoperative day 7 were also recorded. RESULTS. There were 24 knees available for analysis. Mean HKA was 0.1° ± 2.2 varus; 16.7% of knees had coronal outliers exceeding 3°. Mean FFC was 0.9° ± 1.9 varus; 29.2% of femoral components were placed with coronal outliers exceeding 2°. Mean FTC was 1.2° ± 1.6 valgus; 20.8% of tibial components were placed with coronal outliers exceeding 2°. In 3D-CT evaluation, mean femoral coronal and sagittal alignment were 1.2° ± 1.7 varus (outliers exceeding ±2°: 37.5%) and 0.8° ± 2.4 flexion (outliers exceeding ±2°: 20.8%), respectively. Mean tibial coronal and sagittal alignment were 1.1° ± 1.4 valgus (outliers exceeding ±2°: 33.3%) and 0.1° ± 1.6 flexion (outliers exceeding ±2°: 20.8%), respectively. Average surgical time was 96 ± 7.7 minutes, and blood loss was 400 g ± 113 on postoperative day 7. CONCLUSIONS. With radiographic and 3D-CT evaluation, the mean angle error values for the femoral and tibial components were less than 2° in the coronal plane, and less than 1° in the sagittal plane. KneeAlign2 is highly accurate in positioning the femoral and tibial components in TKA. For figures/tables, please contact authors directly.

Anteroposterior (AP) radiographs remain the standard of care for pre- and post-operative imaging during total hip arthroplasty (THA), despite known limitation of plain films, including the inability to adequately account for distortion caused by variations in pelvic orientation. Of specific interest to THA surgeons are distortions associated with pelvic tilt, as unaccounted for tilt can significantly alter radiographic measurements of cup position. Several authors have proposed methods for correcting for pelvic tilt on radiographs but none have proven reliable in a THA population. The purpose of our study was to develop a method for correcting pelvic tilt on AP radiographs in patients undergoing primary or revision THA. CT scans from 20 patients/cadaver specimens (10 male, 10 female) were used to create 3D renderings, from which synthetic radiographs of each pelvis were generated (Figure 1). For each pelvis, 13 synthetic radiographs were generated, showing the pelvis at between −30° and 30° of pelvic tilt, in 5° increments. On each image, 8 unique parameters/distances were measured to determine the most appropriate parameters for calculation of pelvic tilt (Figure 2). The most reliable and accurate of these parameters was determined via regression analysis and used to create gender-specific nomograms from which pelvic tilt measurements could be calculated (Figure 3). The accuracy and reliability of the nomograms and correction method were subsequently validated using both synthetic radiographs (n=50) and stereoradiographic images (n=58). Of 8 parameters measured, the vertical distance between the superior margin of the pubic symphysis and the transischial line (PSTI) was determined to be the most reliable (r=−0.96, ICC=0.94). Mean tilt calculated from synthetic radiographs (0.6°±18.6°) correlated very strongly (r=0.96) with mean known tilt (0.5°±17.9°, p=0.98). Mean pelvic tilt calculated from AP EOS images (3.2°±9.9°) correlated strongly (r=0.77) with mean tilt measured from lateral EOS images (3.8°±8.2°, p=0.74). No gender differences were noted in mean tilt measurements in synthetic images (p=0.98) or EOS images (p=0.45). Our method of measuring PSTI and POD on AP images and applying these measurements to nomograms provides a validated and reliable method for estimating the degree of pelvic tilt on AP radiographs during THA. For any figures or tables, please contact authors directly

Background. Supine positioning during direct anterior approach total hip arthroplasty (DAA THA) facilitates use of fluoroscopy, which has been shown to improve acetabular component positioning on plane radiograph. This study aims to compare 2- dimensional intraoperative radiographic measurements of acetabular component position with RadLink to postoperative 3- dimensional SterEOS measurements. Methods. Intraoperative fluoroscopy and RadLink (El Segundo, CA) were used to measure acetabular cup position intraoperatively in 48 patients undergoing DAA THA. Cup position was measured on 6-week postoperative standing EOS images using 3D SterEOS software and compared to RadLink findings using Student's t-test. Safe-zone outliers were identified. We evaluated for measurement difference of > +/− 5 degrees. Results. RadLink acetabular cup abduction measurement (mean 43.0°) was not significantly different than 3D SterEOS in the anatomic plane (mean 42.6°, p = 0.50) or in the functional plane (mean 42.7°, p = 0.61) (Fig. 1–2). RadLink acetabular cup anteversion measurement (mean 17.9°) was significantly different than 3D SterEOS in both the anatomic plane (mean 20.6°, p = 0.022) and the functional plane (mean 21.2°, p = 0.002) (Fig. 3–4). RadLink identified two cups outside of the safe-zone. However, SterEOS identified 12 (anatomic plane) and 10 (functional plane) outside of the safe-zone (Fig. 5–7). In the functional plane, 58% of anteversion and 92% of abduction RadLink measurements were within +/− 5° of 3D SterEOS. Conclusion. Intraoperative fluoroscopic RadLink acetabular anteversion measurements are significantly different than 3D SterEOS measurements, while abduction measurements are similar. Significantly more acetabular cups are placed outside of the safe- zone when evaluated with 3D SterEOS versus RadLink

The purpose of this study was to examine the utility of the acetabular component introducer as a tool to intra-operatively predict implant inclination in total hip arthroplasty. This study investigated (1) the correlation between intra-operative photographic assessment of cup inclination using the acetabular introducer and that measured on post-operative radiograph; and (2) the accuracy of intra-operative prediction of abduction angle. For this study, we prospectively recruited 56 patients scheduled to receive primary hip arthroplasty from one of two senior surgeons. During the procedure, the lead surgeon provided a prediction of the abduction angle based on the alignment of the impactor attached to the cup in its final seated position. A standardized anteroposterior (AP) photograph was then taken of the acetabular impactor in situ. Abduction angles were measured by two observers on the photographs and post-operative AP pelvis radiographs. Linear regression was used to determine the correlation between the angle of the guide measured on the photographs and the actual position of the implant measured on the radiograph. Descriptive statistics were further used to analyze the accuracy of the intra-operative prediction as compared with the abduction angle measured on the photographs. Measurements of cup position made from post-operative radiographs were significantly correlated with the measurements as assessed by intra-operative photographs (r = 0.34, p = 0.00). Our findings demonstrate that radiological abduction angles tend to be greater than that assessed by intra-operative photographs by a mean of 5.6 degrees (SD = 6.6 degrees; 95% CI = 7.3 to 3.9 degrees). Conversely, surgeon prediction of cup inclination based on the acetabular introducer differed from the radiographic measurements by a mean of 6.8 degrees (SD = 8.7 degrees). There was good agreement between the two observers in both photographic and radiographic measurement (k = 0.95, k = 0.96, respectively). In conclusion, we found that the intra-operative photographic assessment of acetabular cup inclination by acetabular impactor alignment tends to underestimate the abduction angle by a mean of approximately 5 degrees. In addition, intra-operative surgeon estimation of acetabular inclination did not appear accurate in this study demonstrating that cup position should rely on additional visual cues beyond that captured in the anteroposterior view of the cup introducer

Aim. Bone loss is a severe problem in septic revision total knee arthroplasty (RTKA). The use of porous coated metaphyseal sleeves is a promising treatment option for extended bone defects. The currently published mid-term results remain limited and no study has been focused exclusively on septic cases. Our aim was to determine the implant survivorship (with special focus on osseointegration) and the clinical and radiological mid-term outcome of metaphyseal sleeve fixation in septic RTKA surgery (minimum follow-up of 2 years). Method. Between January 2005 and September 2015, 57 patients underwent septic RTKA surgery using metaphyseal sleeves. In 56 patients (98,2 %) who underwent a total of 69 two stage revision procedures, clinical and radiological follow-up examinations were conducted. One patient (1,8 %) was lost to follow-up. The examinations included the American Knee Society Score (KSS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the SF-36 Health survey as well as radiographic measurement to determine if successful osseointegration had been achieved. Results. Thirteen knees (18.8%) had to be re-revised at the time of follow-up (mean 5.3 years, min. 2 – max. 11.2), all due to reinfection (Figure 1). We did not encounter any cases of aseptic loosening. The mean range of motion (92° ± 21°), SSS (7 ± 2), KSS (76 ± 19), WOMAC (70 ± 20), SF-36 MCS (55 ± 14) and SF-36 PCS (35 ± 9) have shown satisfying results. Conclusions. Metaphyseal sleeves have shown very promising mid-term results regarding clinical scores, osseointegration, and aseptic loosening. Our results are the first analysing the performance of metaphyseal sleeves in exclusively septic cases and show that they are a reliable fixation option in septic RTKA patients with severe bone loss

Introduction. Total knee arthroplasty (TKA) has proven to be cost-effective and efficative in the treatment of osteoarthritic knees. Although traditional computer navigation systems improve implant placement, they require fixation of the femoral and tibial reference arrays for software recognition using anchoring pins. This increases the risk of bony fracture, pin sites infection and osteomyelitis. Our study aims to investigate the accuracy of a new inless navigation system (Brainlab VectorVision Knee 2.5 Navigation System) that would avoid these complications. Methods. 119 patients were prospectively recruited over a year. These patients all underwent a primary TKA by a senior surgeon who performs more than 200 TKAs per annum. They were divided into two surgical technique arms. In Group 1, 74 patients underwent TKA using conventional techniques. In Group 2, 45 patients underwent TKA using a pinless navigation system. Post-operative films were taken and three radiographic measurements were measured: 1) Hip-Knee-Ankle Angle (HKA); 2) Coronal Femoral-Component Angle (CFA); 3) Coronal Tibia-Component Angle (CTA) (Figure 1). Two reviewers blinded to the surgical method performed the measurements on the radiographic films on two separate occasions. Results. There was no significant difference between the two groups for age, BMI, gender and side of operated knee. Similarly, there was no difference between the duration of surgery and length of hospital stay in both groups. The mean HKA and CFA were significantly more accurate in the pinless navigation group compared to the conventional group (p=0.003 and p<0.001 respectively). There was no significant difference between the two groups for CTA (Table 1). There was a significant improvement in reducing the number of outliers for lower limb alignment (HKA) and implant placement (CFA and CTA) for the pinless navigation group compared to the conventional group (p<0.05) (Table 2). The radiographic measurements of CFA and CTA on post-operative X-rays were similar to the intra-operative readings obtained from the pinless navigation system (p>0.05) (Table 3). Conclusion. This new pinless navigation system improves lower limb alignment and implant placement in TKA patients, without the risk of pin-related bony fracture, pin sites infection and osteomyelitis

Introduction. Leg length discrepancy is a significant concern after total hip replacement (THR). We hypothesised that the intra-operative use of a navigation system was able to accurately control the leg length during THR. Material. 50 cases have been prospectively analysed. There were 29 men and 21 women, with a mean age of 66.1 years (range, 50 to 80 years), all operated on for THR for end-stage hip osteoarthritis. Methods. All procedures were performed with a non-image based navigation system. The expected correction of the leg length was defined prior to the procedure. The leg length was recorded before any bone resection by the 3D-distance between the pelvic and the femoral navigation trackers when placing the operated leg in a position near the anatomic one. The THR was performed according to the indication of the navigation system. The vertical positioning of the femoral component and the length of the prosthetic neck were defined to achieve the expected planning; however a correction was allowed to compensate for excessive muscular tension or risk of prosthetic instability according to the surgeon's judgment. The final leg length was recorded with the same technique as previously, with an accurate control of the repositioning of the limb in the 3D space by the navigation system. The length variation before and after THR measured by the navigation system was compared to the planning and to a conventional radiographic measurement on plain, standing pelvic X-rays with a Wilcoxon test at a 5% level of significance. The linear correlation coefficient between the different techniques was calculated. The agreement between the different techniques was assessed according to Bland-Altman. Results. The mean planned leg length change was 7.1 ± 6.1 mm. The mean leg length variation was 9.7 ± 4.2 mm as measured by the navigation system, and 11.0 ± 9.2 mm as measured on plain X-rays. The expected goal was achieved within 5 mm for 45 patients (90%). There was no significant difference between paired navigated and radiographic measurements (p=0.46). There was no significant difference between the planning variation and the navigated measurements (p=0.15). There was a good correlation between the planning variation and the navigated measurements (R. 2. =0.59, p<0.001). There was a good coherence between the planning variation and the navigated measurements. Discussion. The hypothesis of the current study was confirmed. The navigation system used in the current study was able to control very accurately the leg length change during THR. This technique of measurements may be more accurate and more precise than any conventional technique of intra-operative leg length control. The incidence of changes in the implant size or position can be easily detected, and the best compromise may be chosen intra-operatively

Inaccurate component placement during total hip arthroplasty (THA) can have significant and costly consequences. Malpositioning of the acetabular cup components can lead to dislocation and revision surgery, while postoperative discrepancies in leg length can lead to biomechanical imbalances, causing chronic low back pain. Current methods for monitoring these parameters intraoperatively rely on manual methods such as tissue tensioning or on the surgeon's experience, both of which are subject to inaccuracies. Computer-assisted navigation, while currently used in only a small percentage of THA procedures, is an emerging technology that has the potential to improve the accuracy with which surgeons place components during THA by providing real-time, intraoperative data. One innovative navigation system – Intellijoint HIP. ®. (Intellijoint Surgical, Waterloo, ON) – has demonstrated its accuracy, time-neutrality, safety and effectiveness in clinical studies and has the potential to improve outcomes and reduce re-admissions and revisions during both primary and revision THA. The ability to assist with placement of the cup component at a preoperative target is a hallmark of navigation systems. In studies examining the proportion of cups placed within Lewinnek's safe zone, significantly more cups were placed within this zone with the Intellijoint system than when using traditional methods (anteversion: 58% vs. 37%, p=0.005; inclination: 87% vs. 67%, p=0.002). Similarly, surgeons were better able to place the cup at a functional orientation of 40 degrees inclination/20 degrees anteversion, with a significantly higher proportion of cups placed within 10 degrees of this target while using the Intellijoint system (70%) than during conventional THA (53%, p=0.02). In comparisons with postoperative imaging, the Intellijoint system has demonstrated excellent accuracy. In a recent study, intraoperative measurements of anteversion and inclination were within 3.3 ± 3.1 degrees and 1.1 ± 0.9 degrees, respectively, of postoperative 3D EOS imaging. Results for leg length discrepancy are similarly accurate: across several studies, the mean difference between navigation and radiographic measurements ranged from 0.3 to 4.3mm. Evidence indicates that the 90-day rates of dislocation and revision surgery following primary THA with the Intellijoint system were substantially lower than rates associated with traditional methods. These results hold true following navigation-assisted revision surgery as well. At 90 days, 1 year and 2 years post-procedure, no dislocations were reported. Beyond dislocation, the overall rate of adverse events in cases using Intellijoint has been reported as remarkably low. No device-related fractures have been reported, nor have any instances of postoperative pain at the sites of the surgical pins supporting the camera and/or tracker components. Finally, there is no significant increase in surgical time associated with the use of this device, with a large study comparing navigated THA with traditional THA showing a 2.9-minute increase in procedural time (p=0.60), 1.0 minute of which occurs prior to primary incision (unpublished data). Computer-assisted navigation – and the Intellijoint HIP system specifically – has demonstrated the ability to improve the accuracy with which surgeons implant components during THA without adversely affecting operating room efficiency or patient safety. This technology has the potential to dramatically improve patient-related outcomes in both the short- and long-term and represents the benefits associated with advanced technologies in the operating room

Introduction. While THA is associated with positive results and long-term improvement in patient quality of life, outcomes are nonetheless associated with adverse events and post-procedural deficits related to discrepancies in leg length (LLD), offset and cup placement. Post-THA errors in these parameters are associated with gait alteration, low back pain and patient dissatisfaction. Such discrepancies often necessitate revision and increasingly lead to medical malpractice litigation. Maintaining accuracy in post-surgical leg length, offset and cup placement during THA is difficult and subject to error. The sensitivity of these factors is highlighted in studies that have shown that a change of as little as 5 degrees of flexion or abduction can induce alterations in leg length of up to several millimeters. Similarly, positioning of implants can alter global and femoral offset, affecting abductor strength, range of motion and overall physical function. Compounding the biochemical issues associated with inaccurate leg length are the costs associated with these deficits. Traditional freehand techniques of managing intra-operative parameters rely on surgeon experience and tissue tensioning to manually place components accurately. These methods, however, are only able to assess leg length and are subject to inaccuracies associated with patient movement or orientation changes during surgery. Mechanical methods of minimizing post-surgical discrepancies have been developed, such as outrigger or caliper devices, although these methods also address leg length only and provide poor feedback regarding offset and center of rotation, therefore providing insufficient data to accurately achieve appropriate post-surgical leg length. Computer-assisted navigation methods provide more data regarding leg length, offset and center of rotation, but are limited by their cumbersome nature and the large capital costs associated with the systems. The Intellijoint HIP. ®. surgical smart tool (Intellijoint Surgical, Inc., Waterloo, ON) is an intra-operative guidance tool that provides surgeons with real time data on leg length, offset and center of rotation, thereby allowing for confident selection of the correct implant in order to ensure appropriate post-surgical biomechanics. The early clinical results from an initial cohort of patients indicate that Intellijoint HIP. ®. is safe and effective. No adverse events were reported in the initial cohort, and the smart tool was able to measure surgical parameters to within 1mm when compared to radiographic measurements. With training cases removed, 100% of cases had a post-procedure leg length discrepancy of less than 5mm. This paper describes the indications, procedural technique and early clinical results of the Intellijoint HIP. ®. smart tool, which offers a safe, accurate and easy-to-use option for hip surgeons to manage leg length, offset and cup position intra-operatively

Introduction. The advantages of the direct anterior approach (DAA) for total hip arthroplasty include the preservation of external rotators and hip abductors thus leading to quicker recovery times. To our knowledge, there is no objective method in the literature to predict the level of difficulty for femoral exposure through the DAA. It would be beneficial to the surgeon learning the DAA to assess difficulty pre-operatively to avoid prolonged operative times. The purpose of this study was to develop a predictive model of femoral exposure difficulty in the DAA using a combination of demographic data and radiographic measurements. Methods. 305 post-operative radiographs of consecutive THA's in patients (184 female, 120 male) with primary or secondary osteoarthritis, mean age 64.6 (range 26–91, SD=11.43) performed through the DAA by one of the co-investigators from 12/2005 to 12/2009 were retrospectively reviewed by two separate observers. The observers were blinded to the difficulty level of femoral exposure. Standard post-operative AP pelvis films were assessed with TraumaCad software (TraumaCad 2.2, Voyant Health, Columbia, MD) to make radiographic measurements as shown in Figure 1–2. Each radiograph was calibrated using the size of the femoral head implant. Exclusion criteria included films that had inadequate coverage of the entire pelvis, mal-rotation, or poor exposure. Statistical analysis was performed using STAT 9.1 (StatCorp; College Station, Texas, USA). A two-sided Kruskal–Wallis test was utilized for non-parametric data. Chi-squared tests and Fisher's Exact Test were used to compare proportions. Statistically significant associations were then added to a multivariate model predicting an outcome of difficult exposure. Results. The difficult exposures were equally distributed throughout the study period. The side of the THA was not associated with a difficult exposure (χ. 2. =0.5516, p=0.968) whereas 66% of difficult cases were male (χ. 2. =38.5323, p=0.0001). Height, weight, BMI, and age were all independent predictors of a difficult exposure, with taller (>175cm) more difficult than shorter (p=.0001), heavier (>100kg) more difficult than lighter (p=.0001), higher BMI (>32) being more difficult than lower BMI (p=.0001), and younger age (<60) being more difficult than older age (p=.003). Radiographic criteria that were predictive of difficult femoral preparation were decreased distance (<110mm) between teardrop signs (p=.0001), increased distance (>211mm) between each SLA (p=0.013), and increased distance (>306mm) between the GT (p=.007). The distance between each ASIS (p=0.375), ASIS to GT (p=.191), and ASIS to SLA (p=.191) were not predictive of difficult femoral preparations. From this, we determined a simple pre-operative scoring tool which allows the surgeon to predict difficult femoral preparations with an 87% sensitivity and easy preparations with >95% specificity. Conclusion. The DAA approach has proven difficult to learn for many surgeons. Careful patient selection can facilitate the learning curve and improve patient outcomes. We describe a simple to implement preoperative rating scale, which gives the surgeon learning DAA an algorithm for appropriate patient selection. Selecting the appropriate patient can reduce the risks to the patient and minimize the cost to society of integrating new surgical techniques

Introduction. Cup malposition in hip arthroplasty and hip resurfacing is associated with instability, accelerated wear, and the need for revision. The current study assesses the validity of intraoperative assessment using a specialized software to analyze intraoperative radiographs. Methods. Cup orientation as measured on intraoperative radiography using the RadLink Galileo Positioning System was assessed in 10 patients. These radiographs were measured by personnel trained to support the system. The results were compared to cup orientation measured by CT. Cup orientation on CT was measured by first identifying the Anterior Pelvic Plane Coordinate system landmarks on a 3D surface model. A multiplanar reconstruction module then allowed for the creation of a plane parallel with the opening plane of the acetabulum. The orientation of the cup opening plane in the AP Plane coordinate space was then calculated. The same definition of cup orientation was used for both methodologies. Results. As compared to direct measurement using CT, the intraoperative radiograph system underestimated anteversion by an average of 8.0 degrees and overestimated cup inclination by 2.9 degrees. The radiographic measurement error in anteversion ranged from −27.4 to +4.0. degrees and for inclination ranged from −2.0 to +5.3 degrees. Conclusion. The use of an intraoperative radiological assessment system is relatively reliable in estimating the inclination of the acetabular component. Anteversion of the acetabular component is extremely poorly assessed by the system