Abstract. Introduction. There is increasing adoption of robotic surgical technology in Total Knee Arthroplasty - The ROSA® knee system can be used in either image-based mode (using pre-operative calibrated radiographs) or imageless modes (using intra-operative bony registration). The Mako knee system is an image-based system (using a pre-operative CT scan). This study aimed to compare surgical accuracy between the ROSA and Mako systems with specific reference to Joint Line Height, Patella Height and Posterior Condylar Offset. Methodology. This was a retrospective review of a prospectively-maintained database of the initial 100 consecutive ROSA TKAs and the initial 50 consecutive Mako TKAs performed by two high volume surgeons. To determine the accuracy of component positioning, the immediate post-operative radiograph was reviewed and compared with the immediate pre-operative radiograph. Patella height was assessed using the Insall-Salvati ratio. Results. There was no significant difference between ROSA TKA and Mako TKA with regards to restoration of joint line height, ROSA mean 0.2mm versus Mako mean 0.3mm (p<0.05), posterior condylar offset, ROSA mean 0.16mm versus Mako mean 0.3mm (p<0.05), and patella height, ROSA mean 0.02 versus Mako mean 0.03 (p<0.05). Conclusion. This study is the first study to compare the accuracy of the ROSA and MAKO knee systems in total knee arthroplasty. Both systems are highly accurate in restoring native posterior condylar offset, joint line height, and patella height in TKA with no significant difference demonstrated between the two robotic systems

Abstract. Introduction. There is growing interest in the use of robotic Total Knee Arthroplasty (TKA) to improve accuracy of component positioning. This is the first study to investigate the radiological accuracy of implant component position using the ROSA® knee system with specific reference to Joint Line Height, Tibial Slope, Patella Height and Posterior Condylar Offset. As secondary aims we compared accuracy between image-based and imageless navigation, and between implant designs (Persona versus Vanguard TKA). Methodology. This was a retrospective review of a prospectively-maintained database of the initial 100 consecutive TKAs performed by a high volume surgeon using the ROSA® knee system. To determine the accuracy of component positioning, the immediate post-operative radiograph was reviewed and compared with the immediate pre-operative radiograph with regards to Joint Line Height, Tibial Slope, Patella Height (using the Insall-Salvati ratio) and Posterior Condylar Offset. Results. Mean age of patients undergoing ROSA TKA was 70 years (range, 55 to 95 years). Mean difference in joint line height between pre and post-operative radiographs was 0.2mm (range −1.5 to +1.8mm, p<0.05), posterior condylar offset mean change 0.16mm (range −1.4 to +1.3mm, p<0.05), tibial slope mean change 0.1 degrees (p<0.05) and patella height mean change 0.02 (range −0.1 to +0.1 p<0.05). No significant differences were found between imageless and image-based groups, or between implant designs (Persona versus Vanguard). Conclusion. This study validates the use of the ROSA® knee system in accurately restoring Joint Line Height, Patella Height and Posterior Condylar Offset

Pelvic discontinuity is a separation through the acetabulum with the ilium displacing superiorly and the ischium/pubis displacing inferiorly. This is a biomechanically challenging environment with a high rate of failure for standard acetabular components. The cup-cage reconstruction involves the use of a highly porous metal cup to achieve biological bone ingrowth on both sides of the pelvic discontinuity and an ilioischial cage to provide secure fixation across the discontinuity and bring the articulating hip center to the correct level. The purpose of this study was to report long term follow up of the use of the cup-cage to treat pelvic discontinuity. All hip revision procedures between January 2003 and January 2022 where a cup-cage was used for a hip with a pelvic discontinuity were included in this retrospective review. All patients received a Trabecular Metal Revision Shell with either a ZCA cage or TMARS cage (Zimmer-Biomet Inc.). Pelvic discontinuity was diagnosed on pre-operative radiographs and/or intraoperatively. Kaplan-Meier survival analysis was performed with failure defined as revision of the cup-cage reconstruction. Fifty-seven cup-cages in 56 patients were included with an average follow-up of 6.25 years (0.10 to 19.98 years). The average age of patients was 72.09 years (43 to 92 years) and 70.2% of patients were female. The five year Kaplan-Meier survival was 92.0% (95% CI 84.55 to 99.45) and the ten year survival was 80.5% (95% CI 58.35 to 102.65). There were 5 major complications that required revision of the cup-cage reconstruction (3 infections and 2 mechanical failures). There were 9 complications that required re-operation without revision of the cup-cage reconstruction (5 dislocations, 3 washouts for infection and one femoral revision for aseptic loosening). In our hands the cup-cage reconstruction has provided a reliable tool to address pelvic discontinuity with an acceptable complication rate

Contemporary indications for unicompartmental knee replacement (UKR) include bone on bone radiographic changes in the medial compartment with relatively preserved lateral and patellofemoral compartments. The role of MRI in identifying candidates for UKR is commonplace. The aim of this study was to assess the relationship between radiographic and MRI pre-operative grade and outcome following UKR. A retrospective analysis of medial UKR patients from 2017 to 2021. Inclusion criteria were medial UKR for osteoarthritis with pre-operative and post-operative Oxford Knee Scores (OKS), pre-operative radiographs and MRI. 89 patients were included. Whilst all patients had grade 4 ICRS scores on MRI, 36/89 patients had grade 3 KL radiographic scores in the medial compartment, 50/89 had grade 4 KL scores on the medial compartment. Grade 3 KL with grade 4 IRCS medial compartment patients had a mean OKS change of 17.22 (Sd 9.190) meanwhile Grade 4 KL had a mean change of 17.54 (SD 9.001), with no statistical difference in the OKS change score following UKR between these two groups (p=0.873). Medial bone oedema was present in all but one patient. Whilst lateral compartment MRI ICRS scores ranged from 1 to 4 there was no association with MRI score of the lateral compartment and subsequent change in oxford score (P value 0.458). Patellofemoral Compartment (PFC) MRI ICRS ranged from 0 to 4. There was no association between PFC ICRS score and subsequent change in oxford knee score (P value .276). Radiographs may under report severity of some medial sided knee osteoarthritis. We conclude that in patients with grade 3 KL score that would normally not be considered for UKR, pre-operative MRI might identify grade 4 ICRS scores and this subset of patients have equivalent outcomes to patients with radiographic Grade 4 KL medial compartment osteoarthritis

Background. Undisplaced Lisfranc-type injuries are subtle but potentially unstable fracture-dislocations with little known about the natural history. These injuries are often initially managed conservatively due to lack of initial displacement and uncertainty regarding subsequent instability at the tarsometatarsal joints (TMTJ). The aim of this study was to determine the secondary displacement rate and the need for delayed operative intervention in undisplaced Lisfranc injuries that were managed conservatively at initial presentation. Methods. Over a 6-year period (2011 to 2017), we identified 24 consecutive patients presenting to a university teaching hospital with a diagnosis of an undisplaced Lisfranc-type injury that was initially managed conservatively. Pre-operative radiographs were reviewed to confirm the undisplaced nature of the injury (defined as a diastasis< 2mm at the second TMTJ). The presence of a ‘fleck’ sign (small bony avulsion of the second metatarsal) was also noted. Electronic patient records and sequential imaging (plain radiographs/CT/MRI) were scrutinized for demographics, mechanism of injury and eventual outcome. Results. The mean age of the patients at the time of injury was 42 years (19 Female). 96% (23/24) were low energy injuries and 88% (21/24) had a positive ‘fleck sign’. The secondary displacement rate in this group of patients was 62.5% (15/24) over a median interval of 14 days (range 0 to 482 days). 12 patients underwent open reduction internal fixation after a median interval of 29 days (range 1 to 294 days) from their initial injury. One patient required TMTJ fusion at 19 months and two patients were managed non-operatively. The injury remained undisplaced in 37.5% patients (9/24) with only one patient requiring subsequent TMTJ fusion at 5 months. Conclusion. Undisplaced Lisfranc injuries have a high rate of secondary displacement and warrant close follow-up. Early primary stabilisation of undisplaced Lisfranc injuries should be considered to prevent unnecessary delays in surgical treatment

Abstract. Introduction. Mako robotic assisted knee arthroplasty requires a planning CT scan within 8 weeks of surgery according to the supplier's protocol. This is often impractical, therefore we evaluated whether CT scans remain valid for an extended period. Methodology. Patients undergoing Mako partial (PKA) and total (TKA) knee arthroplasty were identified from our hospital database. The hospital PACS system was used to define the time interval between the initial planning CT scan and surgery, and whether further imaging was required prior to surgery. Results. 443 consecutive Mako cases (225 TKA and 218 PKA) were undertaken between November 2019 and December 2021 (33 cases to March 2020, and 410 cases from August 2020). CT scans were done within 8 weeks of surgery in 229 patients (51.7%); between 8 and 24 weeks in 148 patients (33.4%); between 24 and 48 weeks in 53 patients (12.0%); and more than 48 weeks in 13 patients (2.9%). Repeat pre-operative radiographs were done in the first 43 patients with a delay to surgery of more than 8 weeks following their CT scan. No gross anatomical changes were identified, and this practice was therefore discontinued. No patients required a repeat CT scan. There were no intra-operative registration errors in any patient in this series. Conclusion. Planning CT scans were valid for up to one year in a large series of patients undergoing Mako PKA and TKA. This may allow for more cost-effective use of resources, while minimising irradiation to patients

Abstract. Objectives. Epiphysiodesis is a commonly used treatment for lower limb angular deformities. However, in recent years, distal tibial growth modulation using ‘eight plates’ or screws has emerged as an alternative treatment for paediatric foot and ankle disorders, such as CTEV. Our objective was to assess the efficacy of distal tibial modulation in correcting various paediatric foot and ankle disorders. Methods. This retrospective study analysed 205 cases of paediatric foot and ankle disorders treated between 2003 and 2022, including only cases where the eight plate or screw was fixed on the anterior surface of the distal tibia. Our aim was to measure post-operative changes in dorsiflexion, the distal tibial angle, and the tibiocalcaneal angle by examining clinical records and radiology reports. Results. We identified nine cases (nine feet) meeting the full inclusion criteria, comprising seven cases of CTEV, one case of arthrogryposis, and one case of cavovarus foot. The cohort consisted of five male and four female patients, with a mean age of 10 years and 9 months at the time of surgery. Seven cases involved the left tibia, and two cases involved the right tibia. The mean time between pre-operative X-ray to surgery was 168 days, and the mean turnaround time between surgery and post-operative X-ray was 588 days. A mean change in the distal tibial angle of 4.33 degrees was noted. However, changes in dorsiflexion were documented in only one case, which showed a change of 13 degrees. Notably, our average distal tibial angle was significantly lower than reported in the literature, at 4.33 degrees. Additionally, some studies in the literature used the Oxford Ankle Foot Questionnaire for Children to assess pre- and post-operative outcomes, but it is important to note that it is validated only for children aged 5 to 16. Furthermore, most cases reported an improved tibiocalcaneal angle except for an anomaly of 105 degrees. We assessed satisfactory patient outcomes using patient notes. Out of the 6 procured notes, one has been discharged. The rest are still under yearly or 6-monthly review and are at various stages, such as physiotherapy, removing the eight plate, or requiring further surgery. The most common presentations at review are plantaris deformity and pain. Conclusions. Our study suggests that distal tibial growth modulation can be an effective treatment option for selected paediatric foot and ankle disorders. However, due to the limited number of cases in our study, the lack of documentation of changes in dorsiflexion, and a lack of pre- and post-operative outcomes using a standardised method, further research is needed to investigate this procedure's long-term outcomes and potential complications. 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

Neuromuscular scoliosis patients face rates of major complications of up to 49%. Along with pre-operative risk reduction strategies (including nutritional and bone health optimization), intra-operative strategies to decrease blood loss and decrease surgical time may help mitigate these risks. A major contributor to blood loss and surgical time is the insertion of instrumentation which is challenging in neuromuscular patient given their abnormal vertebral and pelvic anatomy. Standard pre-operative radiographs provide minimal information regarding pedicle diameter, length, blocks to pedicle entry (e.g. iliac crest overhang), or iliac crest orientation. To minimize blood loss and surgical time, we developed an “ultra-low dose” CT protocol without sedation for neuromuscular patients. Our prospective quality improvement study aimed to determine: if ultra-low dose CT without sedation was feasible given the movement disorders in this population; what the radiation exposure was compared to standard pre-operative imaging; whether the images allowed accurate assessment of the anatomy and intra-operative navigation given the ultra-low dose and potential movement during the scan. Fifteen non-ambulatory surgical patients with neuromuscular scoliosis received the standard spine XR and an ultra-low dose CT scan. Charts were reviewed for etiology of neuromuscular scoliosis and medical co-morbidities. The CT protocol was a high-speed, high-pitch, tube-current modulated acquisition at a fixed tube voltage. Adaptive statistical iterative reconstruction was applied to soft-tissue and bone kernels to mitigate noise. Radiation dose was quantified using reported dose indices (computed tomography dose index (CTDIvol) and dose-length product (DLP)) and effective dose (E), calculated through Monte-Carlo simulation. Statistical analysis was completed using a paired student's T-test (α = 0.05). CT image quality was assessed for its use in preoperative planning and intraoperative navigation using 7D Surgical System Spine Module (7D Surgical, Toronto, Canada). Eight males and seven females were included in the study. Their average age (14±2 years old), preoperative Cobb angle (95±21 degrees), and kyphosis (60±18 degrees) were recorded. One patient was unable to undergo the ultra-low dose CT protocol without sedation due to a co-diagnosis of severe autism. The average XR radiation dose was 0.5±0.3 mSv. Variability in radiographic dose was due to a wide range in patient size, positioning (supine, sitting), number of views, imaging technique and body habitus. Associated CT radiation metrics were CTDIvol = 0.46±0.14 mGy, DLP = 26.2±8.1 mGy.cm and E = 0.6±0.2 mSv. CT radiation variability was due to body habitus and arm orientation. The radiation dose differences between radiographic and CT imaging were not statistically significant. All CT scans had adequate quality for preoperative assessment of pedicle diameter and orientation, obstacles impeding pedicle entry, S2-Alar screw orientation, and intra-operative navigation. “Ultra-low dose” CT scans without sedation were feasible in paediatric patients with neuromuscular scoliosis. The effective dose was similar between the standard preoperative spinal XR and “ultra-low dose” CT scans. The “ultra-low dose” CT scan allowed accurate assessment of the anatomy, aided in pre-operative planning, and allowed intra-operative navigation despite the movement disorders in this patient population

Neuromuscular scoliosis patients face rates of major complications of up to 49%. Along with pre-operative risk reduction strategies (including nutritional and bone health optimization), intra-operative strategies to decrease blood loss and decrease surgical time may help mitigate these risks. A major contributor to blood loss and surgical time is the insertion of instrumentation which is challenging in neuromuscular patient given their abnormal vertebral and pelvic anatomy. Standard pre-operative radiographs provide minimal information regarding pedicle diameter, length, blocks to pedicle entry (e.g. iliac crest overhang), or iliac crest orientation. To minimize blood loss and surgical time, we developed an “ultra-low dose” CT protocol without sedation for neuromuscular patients. Our prospective quality improvement study aimed to determine:. if ultra-low dose CT without sedation was feasible given the movement disorders in this population;. what the radiation exposure was compared to standard pre-operative imaging;. whether the images allowed accurate assessment of the anatomy and intra-operative navigation given the ultra-low dose and potential movement during the scan. Fifteen non-ambulatory surgical patients with neuromuscular scoliosis received the standard spine XR and an ultra-low dose CT scan. Charts were reviewed for etiology of neuromuscular scoliosis and medical co-morbidities. The CT protocol was a high-speed, high-pitch, tube-current modulated acquisition at a fixed tube voltage. Adaptive statistical iterative reconstruction was applied to soft-tissue and bone kernels to mitigate noise. Radiation dose was quantified using reported dose indices (computed tomography dose index (CTDIvol) and dose-length product (DLP)) and effective dose (E), calculated through Monte-Carlo simulation. Statistical analysis was completed using a paired student's T-test (α= 0.05). CT image quality was assessed for its use in preoperative planning and intraoperative navigation using 7D Surgical System Spine Module (7D Surgical, Toronto, Canada). Eight males and seven females were included in the study. Their average age (14±2 years old), preoperative Cobb angle (95±21 degrees), and kyphosis (60±18 degrees) were recorded. One patient was unable to undergo the ultra-low dose CT protocol without sedation due to a co-diagnosis of severe autism. The average XR radiation dose was 0.5±0.3 mSv. Variability in radiographic dose was due to a wide range in patient size, positioning (supine, sitting), number of views, imaging technique and body habitus. Associated CT radiation metrics were CTDIvol = 0.46±0.14 mGy, DLP = 26.2±8.1 mGy.cm and E = 0.6±0.2 mSv. CT radiation variability was due to body habitus and arm orientation. The radiation dose differences between radiographic and CT imaging were not statistically significant. All CT scans had adequate quality for preoperative assessment of pedicle diameter and orientation, obstacles impeding pedicle entry, S2-Alar screw orientation, and intra-operative navigation. “Ultra-low dose” CT scans without sedation were feasible in paediatric patients with neuromuscular scoliosis. The effective dose was similar between the standard preoperative spinal XR and “ultra-low dose” CT scans. The “ultra-low dose” CT scan allowed accurate assessment of the anatomy, aided in pre-operative planning, and allowed intra-operative navigation despite the movement disorders in this patient population

INTRODUCTION. Despite our best efforts, orthopaedic surgeons do not always achieve desired results in acetabular cup positioning in total hip arthroplasty. New advancements in digital radiography and image analysis software allow contemporaneous assessment of cup position in real-time during the surgical procedure. The purpose of this study was to describe and validate a technique in obtaining a true AP Pelvis radiograph in the lateral decubitus position to accurately assess cup position intra-operatively (Figure 1). METHODS. 350 consecutive patients undergoing THA through a soft-tissue sparing posterior approach were prospectively enrolled. Standard pre-operative supine radiographs were taken in the office to serve as a reference for intra-operative pelvic orientation and templating. Intra-operative AP Pelvis radiographs were obtained with the patient in the lateral decubitus position to appropriately match the pre-operative radiograph. Adjustments were made to correct for pelvic rotation by rotating the operating room table forward or backward. Radiographic beam angle adjustments allowed the surgeon to match pre-operative and intra-operative pelvic tilt (Figure 2). Two independent observers measured cup abduction angle. RESULTS. 95% of cups were placed within 30–50 degrees of abduction, with a mean angle of 38 degrees (STD +/− 5). 100% of cups measured post-operatively were placed within 3 degrees of their intra-operative measurement. Mean anteversion was 27.5 degrees (STD +/− 3.5). Intra-operative radiographs were repeated in 88% of cases in order to match to the pre-operative radiographs. The cup was repositioned in 28% of cases based on intra-operative measurements. Impingement during range of motion testing occurred in 3% of cases despite acceptable measurements, necessitating cup reposition. The intercross correlation coefficient between the two observers was 0.92. There was one dislocation reported in the 2-year follow-up. Changes in the pelvic inlet and outlet orientation changed the abduction angle measurement in a predictable way. We developed a formula and 3D model to predict the abudction angle based on the pelvic tilt, where a more outlet view would increase the abduction angle measurement (Figure 3). DISCUSSION AND CONCLUSION. Advancements in digital radiography allow for real-time cup position assessment, creating the opportunity for the surgeon to make the appropriate changes and confirm precise placement during the procedure. For figures/tables, please contact authors directly.

When performing total hip replacements in patients with hip dysplasia, acetabular augmentation may be required to prevent early component failure. Preoperative radiographic templating may help estimate acetabularcomponent coverage but has not previously been shown to predict the need for augmentation. We developed a simple method to estimate the percentage of acetabular component coverage from pre-operative radiographs (True: False cup ratio). We aimed to evaluate whether this couldpredict the need foracetabular augmentation at primary total hip replacement for patients with dysplastic hips. We reviewed all patients with hip dysplasia who underwent a primary total hip replacement from 2005–2012. Classification of hip dysplasia (Crowe), centre edge angle (CEA), Sharp and Tonnis angles were determined on pre-operative radiographs for each patient. Templating was performed on anteroposteriorand lateral view hip radiographs to determine the likely percentage of acetabular component coverage using the True: False cup ratio. Patients requiring acetabular augmentation at time of primary total hip arthroplasty were noted. 128 cases were reviewed, 31 (24%) required acetabularaugmentation. Comparison between augmented and non-augmented cases revealed no difference in the mean CEA (p = 0.19), Sharp angles (p = 0.76) or Tonnis angles (p = 0.32). A lower True Cup: False Cup ratio was observed in the augmented groupcompared to the non-augmented group(median = 0.68 vs 0.88, p < 0.01). Preoperative templating can help predict which dysplastic hips are likely to require acetabular augmentation at primary total hip replacement

Thoracic hyperkyphosis (TH – Cobb angle >40°) is correlated with rotator cuff arthropathy and associated with anterior tilting and protraction of scapula, impacting the glenoid orientation and the surrounding musculature. Reverse total shoulder arthroplasty (RTSA) is a reliable surgical treatment for patients with rotator cuff arthropathy and recent literature suggests that patients with TH may have comparable range of motion after RTSA. However, there exists no study reporting the possible link between patient-reported outcomes, humeral retroversion and TH after RTSA. While the risk of post-operative complications such as instability, hardware loosening, scapular notching, and prosthetic infection are low, we hypothesize that it is critical to optimize the biomechanical parameters through proper implant positioning and understanding patient-specific scapular and thoracic anatomy to improve surgical outcomes in this subset of patients with TH. Patients treated with primary RTSA at an academic hospital in 2018 were reviewed for a two-year follow-up. Exclusion criteria were as follows: no pre-existing chest radiographs for Cobb angle measurement, change in post-operative functional status as a result of trauma or medical comorbidities, and missing component placement and parameter information in the operative note. As most patients did not have a pre-operative chest radiograph, only seven patients with a Cobb angle equal to or greater than 40° were eligible. Chart reviews were completed to determine indications for RTSA, hardware positioning parameters such as inferior tilting, humeral stem retroversion, glenosphere size/location, and baseplate size. Clinical data following surgery included review of radiographs and complications. Follow-up in all patients were to a period of two years. The American Shoulder and Elbow Surgeons (ASES) Shoulder Score was used for patient-reported functional and pain outcomes. The average age of the patients at the time of RTSA was 71 years old, with six female patients and one male patient. The indication for RTSA was primarily rotator cuff arthropathy. Possible correlation between Cobb angle and humeral retroversion was noted, whereby, Cobb angle greater than 40° matched with humeral retroversion greater than 30°, and resulted in significantly higher ASES scores. Two patients with mean Cobb angle of 50° and mean humeral retroversion 37.5° had mean ASES scores of 92.5. Five patients who received mean humeral retroversion of 30° had mean lower ASES scores of 63.7 (p < 0 .05). There was no significant correlation with glenosphere size or position, baseplate size, degree of inferior tilting or lateralization. Patient-reported outcomes have not been reported in RTSA patients with TH. In this case series, we observed that humeral stem retroversion greater than 30° may be correlated with less post-operative pain and greater patient satisfaction in patients with TH. Further clinical studies are needed to understanding the biomechanical relationship between RTSA, humeral retroversion and TH to optimize patient outcomes

Pathologies such as Scapho-Lunate Advanced Collapse (SLAC), Scaphoid Non-union Advanced Collapse (SNAC) and Kienbock's disease can lead to arthritis in the wrist. Depending on the articular surfaces that are involved, motion preserving surgical procedures can be performed. Proximal Row Carpectomy (PRC) and Four Corner Fusion (4CF) are tried and tested surgical options. However, prospective studies comparing the two methods looking at sufficient sample sizes are limited in the literature. The purpose of this study was to prospectively compare the early results of PRC vs 4CF performed in a single centre. Patients with wrist arthritis were prospectively enrolled (2015 to 2021) in a single centre in Vancouver, Canada. Thirty-six patients and a total of 39 wrists underwent either a PRC (n=18) or 4CF (n=21) according to pre-operative clinical, radiographical, and intra-operative assessment. Patient-Rated Wrist Evaluation (PRWE) scores were obtained preoperatively, as well as at six months and one year post operatively. Secondary outcomes were range of motion (ROM) of the wrist, grip strength, reoperation and complication rates. Statistical significance was set at p=0.05. Respectively for PRC and 4CF, the average PRWE scores at baseline were 61.64 (SD=19.62) and 63.67 (SD=20.85). There was significant improvement at the six-month mark to 38.81 (SD=22.95) (p=0.031) and 41.33 (SD=26.61) (p=0.007), then further improvement at the 12month mark to 33.11 (SD=23.42) (p=0.007) and 36.29 (SD=27.25) (p=0.002). There was no statistical difference between the two groups at any time point. Regarding ROM, statistical difference was seen in pronation for the PRC group at the 6month mark from an average of 72.18 deg to 61.56 deg and in flexion at the 12 month mark from 47.89 deg to 33.50 deg. All other parameters did not show statistically significant difference post operatively. For ROM of the 4CF group, only flexion at the 12month mark showed statistically significant change from an average of 48.81 deg to 38.03 deg. There was no statistical difference in pre-operative ROM between the two groups. One patient in the 4CF group required a revision for delayed union, and three patients ended up with ulnar sided wrist pain. Patients undergoing PRC and 4CF showed significant improvement in post operative PRWE scores, this reflects existing literature. For 4CF care must be taken to minimise ulnar sided wrist pain by relatively shortening the unar sided carpal column mass. ROM analysis showed that patients lost some wrist flexion ROM post-operatively at the 12month mark with both PRC and 4CF. However, other ROM parameters were unchanged

Cup position planning for total hip replacement (THR) is a complex task which is influenced by several factors. Whereas aspects like appropriate implant fixation and bone stock preservation are rather evaluated according to intra-operative findings, functional analyses using biomechanical hip models can rely on pre-operative imaging. Due to the wide availability and cost-efficiency of X-ray imaging technology along with the common restriction of biomechanical evaluations to the frontal plane, pre-operative imaging for such purposes is usually limited to AP radiographs. One example is biomechanical optimisation based on the so-called BLB score, which has already been introduced into clinical practice. In this approach, the assumed suitability of potential hip centres of rotation (CORs) is presented to the surgeon by applying colour-coding within the pre-operative AP radiograph. However, to realise the plan, the surgeon has to transfer the 2D positions presented in the radiograph into the 3D surgical site. We developed a CT-based simulation tool allowing for the generation of 3D bone surface models as well as standardised digitally reconstructed radiographs (DRRs). Within a 3D view, the cup, which is represented as a hemisphere, can freely be shifted in the coronal plane. The 2D point corresponding to the COR defined by the hemisphere is then automatically computed. In our study, four CT datasets of hips with large bony defects were used. After segmentation 3D bone surface models were generated. These bone surface models were aligned on the basis of the pelvic coordinate system [3], and standardised AP DRRs were computed. BLB score evaluation in intact hips assumes that the central beam passes through the centroid of both hip CORs. As only the contra-lateral hip COR was available due to the defects, a virtual ipsi-lateral COR was obtained by mirroring the contra-lateral hip across the mid-sagittal plane. Twelve surgeons (divided into two groups of six each according to their experience) had the task to shift the cup such that its 3D position would best match a predefined 2D target position, which was close to the virtual ipsi-lateral COR and displayed as a cross within the standardised DRR. However, the current 2D position corresponding to the current 3D position was not revealed during positioning. Once the user was satisfied with the 3D position, the corresponding 2D position was recorded. The following results were obtained (mean ± SD across six surgeons of the respective group) for the four patients:. x-error, more experienced: 2.0 ± 6.1; −3.0 ± 5.9; 4.1 ± 4.8; 2.1 ± 5.2; x-error, less experienced: 4.3 ± 4.2; −3.1 ± 1.8; 1.9 ± 4.0; 5.2 ± 4.1; |x-error|, more experienced: 5.2 ± 3.0; 5.4 ± 3.2; 5.5 ± 2.7; 4.3 ± 3.0;|x-error|, less experienced: 4.3 ± 4.2; 3.1 ± 1.8; 3.3 ± 2.7; 5.7 ± 3.3; y-error, more experienced: 12.0 ± 9.1; 0.3 ± 4.3; 6.2 ± 6.6; 1.9 ± 3.2;. y-error, less experienced: 6.1 ± 3.1; 0.8 ± 4.0; 2.4 ± 5.5; 1.4 ± 4.1;|y-error|, more experienced: 12.0 ± 9.1; 3.2 ± 2.6; 6.2 ± 6.6; 3.0 ± 1.9;|y-error|, less experienced: 6.1 ± 3.1; 3.4 ± 1.6; 4.6 ± 3.3; 3.2 ± 2.6;total error, more experienced: 13.5 ± 8.9; 6.6 ± 3.5; 9.8 ± 4.1; 5.4 ± 3.4;total error, less experienced: 8.5 ± 2.7; 4.9 ± 1.5; 6.5 ± 2.5; 6.7 ± 3.8. Our experimental results show that mental 2D/3D matching for cup positioning in pelvises with bony defects is a difficult task, and that mental 2D/3D matching cannot be expected to yield the correct 3D cup positions corresponding to positions predefined in radiographs. The largest errors were found in the patient with the lowest image quality suggesting that image quality plays an important role. On contrary, experience was not found to be an important factor. We believe that in clinical practice mental 2D/3D matching between pre-operative radiographs and the surgical site without the help of 3D imaging or special tools would be more difficult than the task given in this study because only small portions of the pelvis would be exposed. Furthermore, as additional aspects of cup positioning would need to be taken into consideration simultaneously, the mental load could be expected to be higher. We conclude that in hips with large bony defects cup positioning based on pre-operative radiographs is highly unreliable without additional computer-assistance or intra-operative imaging. If pre-operative radiographs are needed for functional analyses, combination with 3D image data seems attractive: Firstly, 3D images can easily be used for navigation; secondly, they allow for the generation of highly standardised views, which is essential for comparability across multiple patients. Future studies relying on more datasets with a wider range of defects could also investigate whether cranio-caudal or medio-lateral positioning errors prevail. This is an interesting question since the BLB score usually is much more specific in the medio-lateral direction than in the cranio-caudal direction, implying that correct 2D/3D matching for the cranio-caudal direction appears less important. In the current study involving only four hips, however, no clear tendency could be observed. This work has been funded in part by the German Ministry for Education and Research (BMBF) in the framework of the orthoMIT project under grant No. BMBF 01EQ0802/BMBF 01IBE02C

Introduction. Robotics have been applied to total knee arthroplasty (TKA) to improve surgical precision in components’ placement, providing a physiologic ligament tensioning throughout knee range of motion. The purpose of the present study is to evaluate femoral and tibial components’ positioning in robotic-assisted TKA after fine-tuning according to soft tissue tensioning, aiming symmetric and balanced medial and lateral gaps in flexion/extension. Materials and Methods. Forty-three consecutive patients undergoing robotic-assisted TKA between November 2017 and November 2018 were included. Pre-operative radiographs were performed and measured according to Paley's. The tibial and femoral cuts were performed based on the individual intra-operative fine-tuning, checking for components’ size and placement, aiming symmetric medial and lateral gaps in flexion/extension. Cuts were adapted to radiographic epiphyseal anatomy and respecting ±2° boundaries from neutral coronal alignment. Robotic data were recorded, collecting information relative to medial and lateral gaps in flexion and extension. Results. Patients were divided based on the pre-operative coronal mechanical femoro-tibial angle (mFTA). Only knees with varus deformity (mFTA<178°), 29 cases, were taken into account. On average, the tibial component was placed at 1.2°±0.5 varus. Femoral component fine-tuning based on soft-tissues tensioning in extension and flexion determined the following alignments: 0.2°±1.2 varus on the coronal plane and 1.2°±2.2° external rotation with respect to the trans-epicondylar axis (TEA) as measured on the CT scan in the horizontal plane. The average gaps after femoral and tibial resections, resulted as follows: 19.5±0.8 mm on the medial side in extension, 20.0±0.9 mm on the lateral side in extension, 19.1±0.7 mm on the medial side in flexion and 19.5±0.7 mm on the lateral side in flexion. On average, the post-implant coronal alignment as reported by the robotic system resulted 2.0°±1.5 varus. Discussion. The proposed robotic-arm assisted TKA technique, aiming to preserve the integrity of the ligaments, provides balanced and symmetric gaps in flexion and extension and an anatomic femoral and tibial component's placement with post-implant coronal alignment within ±2° from neutral alignment

It is believed by some that knee radiographs may underestimate the extent of osteoarthritis. Often severe changes are noted at arthroscopic assessment despite the observation of preserved joint spaces on plain radiographs. This has important implications regarding the indications for different types of partial joint replacement if damage is underestimated. Aims:. To determine the correlation if any between radiographic findings and arthroscopic findings. To determine which radiographs are consistently useful for assessment of osteoarthritis and to determine the limitations. To identify the proportions of patients with certain patterns of damage who might be suitable in the future for different types of partial replacement. Methods and patient selection: The pre-operative radiographs and intra-operative articular surface mappings were collected for 100 consecutive patients undergoing prospectively audited outcome of arthroscopic debridement. All the patients examined were aged 40 and above with knee pain. The intra-operative findings and any work done (debridement of meniscal tears or cartilage flap tears) were also recorded on zoned articular maps and meniscal diagrams. The pre-operative radiographs (AP standing, lateral, Rosenberg and skyline views) were examined and graded using the Kellgren and Lawrence grading system. Results: Correlations made between arthroscopic findings and AP standing views yielded a sensitivity of 72% and specificity of 64%. The positive predictive value was 91% and negative predictive value was 32%. Rosenberg views were better at predicting the presence of osteoarthritis (sensitivity 76%, specificity 88%, positive predictive value 97%, negative predictive value 44%). Skyline views were found to particularly unreliable in assessment of patello-femoral damage. Analysis of the actual patterns of articular damage found at arthroscopy did show that it is possible to identify cohorts of patients who may in future be suitable for different types of partial replacement. Conclusions: Radiographs and in particular skyline views are limited in terms of sensitivity and specificity in the prediction of osteoarthritis. Rosenberg views offer better prediction of osteoarthritis compared with weight bearing AP radiographs. Arthroscopy carried out in any event for clinical indications appears to offer useful additional information regarding indications for future surgery

Background. Implant loosening is a common cause of a poor outcome and pain after total knee arthroplasty (TKA). Despite the increase in use of expensive techniques like arthrography, the detection of prosthetic loosening is often unclear pre-operatively, leading to diagnostic uncertainty and extensive workup. The objective of this study was to evaluate the ability of a machine learning (ML) algorithm to diagnose prosthetic loosening from pre-operative radiographs, and to observe what model inputs improve the performance of the model. Methods. 754 patients underwent a first-time revision of a total joint at our institution from 2012–2018. Pre-operative X-Rays (XR) were collected for each patient. AP and lateral X-Rays, in addition to demographic and comorbidity information, were collected for each patient. Each patient was determined to have either loose or fixed prosthetics based on a manual abstraction of the written findings in their operative report, which is considered the gold standard of diagnosing prosthetic loosening. We trained a series of deep convolution neural network (CNN) models to predict if a prosthesis was found to be loose in the operating room from the pre-operative XR. Each XR was pre-processed to segment the bone, implant, and bone-implant interface. A series of CNN models were built using existing, proven CNN architectures and weights optimized to our dataset. We then integrated our best performing model with historical patient data to create a final model and determine the incremental accuracy provided by additional layers of clinical information fed into the model. The models were evaluated by its accuracy, sensitivity and specificity. Results. The CNN we built demonstrated high performance at detecting prosthetic loosening from radiographs alone. Our first model built from scratch on just the image as an input had an accuracy of 70%. Our final model which was built by fine-tuning and optimizing a publicly available model named DenseNet, combining the AP and lateral radiographs, incorporating information from the patient history, had an accuracy, sensitivity, and specificity of 98.5%, 93.9%, and 99.5% on the patients that it was trained on, and an accuracy, sensitivity, and specificity of 88.3%, 70.2%, and 95.6% on the patients it was tested on. Conclusions. The use of machine learning (ML) can accurately detect the presence of prosthetic loosening based on plain radiographs. Its accuracy is progressively enhanced when additional clinical data is added to the loosening analysis algorithm. While this type of machine learning may not be sufficient in its present state of development as a standalone metric of loosening, it is clearly a useful augment for clinical decision making in its present state. Further study and development will be needed to determine the feasibility of applying machine learning as a more definitive test in the clinical setting. For figures, tables, or references, please contact authors directly

Osteochondral lesions (OCLs) of the talus are a challenging and increasingly recognized problem in chronic ankle pain. Many novel techniques exist to attempt to treat this challenging entity. Difficulties associated with treating OCLs include lesion location, size, chronicity and problems associated with potential graft harvest sites. Matrix associated stem cell transplantation (MAST) is one such treatment described for larger lesions >15mm. 2. or failed alternative therapies. This cohort study describes a 5 year review of the outcomes of talar lesions treated with MAST. A review of all patients treated with MAST by a single surgeon was conducted. Pre-operative radiographs, MRIs and FAOS outcome questionnaire scores were conducted. Intraoperative classification was conducted to correlate with imaging. Post-operative outcomes included FAOS scores, return to sport, revision surgery/failure of treatment and progression to arthritis/fusion surgery. 32 patients were identified in this cohort. There were 10 females, 22 males, with an average age of 35. 01. 73% had returned and continued playing active sport. 23 patients underwent MAST in the setting of a failed previous operative attempt, with just 9 having MAST as a first option. 9 patients out of 32 had a further procedure. Two patients had a further treatment directed at their OCL. Two patients had a fusion, 2 had a cheilectomy at > 4 years for impingement, one had a debridement of their anterolateral gutter, one had debridement for arthrofibrosis, one patient had a re alignment calcaneal osteotomy with debridement of their posterior tibial tendon. MAST has demonstrated positive results in lesions which prove challenging to treat, even in a “failed microfracture” cohort

Achievement of adequate exposure in revision total knee arthroplasty is critical as it reduces the surgical time, enhances the ability for both component removal and reconstruction, and avoids devastating complications such as extensor mechanism disruption. However, this can be challenging as prior multiple surgeries and limited mobility contribute to a loss of tissue elasticity, thickened capsular envelope, and peri-articular soft tissue adhesions. A thorough pre-operative assessment of a patient's past surgical history, comorbidities, pre-operative radiographs (i.e. the presence of severe patella baja), and physical examination including range of motion, prior incisions, and soft tissue pliability are useful in determining the appropriate surgical techniques necessary for a successful revision. A systematic approach to the ankylosed knee is critical. Most techniques are geared towards mobilization of the extensor mechanism to safely displace the patella for component exposure. The initial exposure should consist of a long skin incision, a subperiosteal medial release, and debridement of suprapatellar, medial, and lateral adhesions to the femoral condyles. A lateral capsular release can prove helpful in further mobilization of the extensor mechanism. When performing a medial parapatellar arthrotomy it's important to keep in mind further extensile exposure techniques that may be required. For example, the arthrotomy should not extend proximally into the vastus intermedius or rectus femoris in the event that a quadriceps snip technique is to be used as this can compromise the ability to repair this exposure. Despite a large exposure and release of adhesions, sometimes the extensor mechanism remains at risk of rupture and adequate visualization cannot be obtained. In this event, extensile exposures such as a quadriceps snip, quadriceps turndown or tibial tubercle osteotomy are considered. The location of the patella often dictates the best exposure option as severe patella baja may not be overcome with a proximally based release. The quadriceps snip is most commonly used and provides improved exposure without the necessity of modifying the patient's post-operative rehabilitation. In addition, it can be extended to a quadriceps turndown which vastly improves visualization, but at the expense of needing to immobilise the knee post-operatively. A tibial tubercle osteotomy can also be used and provides excellent exposure especially in the case of severe patella baja or when removal of a cemented tibial stem is required. It preserves the extensor muscles, but risks include increased post-operative wound drainage due to limited soft tissue coverage, failure of fixation, or fracture of the tibial tubercle fragment or tibial shaft. Exposure in revision total knee arthroplasty is critical. Fortunately, this can be reliably achieved with a systematic approach to the knee and through the use of several extensile exposures at the surgeon's discretion

Ceramic-on-ceramic bearings provide a solution to the osteolysis seen with traditional metal-on-polyethylene bearings. Sporadic reports of ceramic breakage and squeaking concern some surgeons and this bearing combination can show in vivo signs of edge loading wear which was not predicted from in vitro studies. Taper damage or debris in the taper between the ceramic and metal may lead to breakage of either a ceramic head or insert. Fastidious surgical technique may help to minimise the risk of ceramic breakage. Squeaking is usually a benign complication, most frequently occurring when the hip is fully flexed. Rarely, it can occur with each step of walking when it can be sufficiently troublesome to require revision surgery. The etiology of squeaking is multifactorial in origin. Taller, heavier and younger patients with higher activity levels are more prone to hips that squeak. Cup version and inclination are also relevant factors. Osteolysis following metal-on-UHMW polyethylene Total Hip Arthroplasty (THA) is well reported. Earlier generation ceramic-on-ceramic bearings did produce some osteolysis, but in flawed implants. As third and now fourth generation ceramic THAs come into mid- and long-term service, the orthopaedic community has begun to see reports of high survival rates and very low incidence of osteolysis in these bearings. The technique used by radiologists for identifying the nature of lesions on Computed Tomography (CT) scan is the Hounsfield score which will identify the density of the tissue within the lucent area. Commonly the radiologist will have no access to previous imaging, especially pre-operative imaging if a long time has elapsed. With such a low incidence of osteolysis in this patient group, what, then, should a surgeon do on receiving a CT report on a ceramic-on-ceramic THA, which states there is osteolysis? This retrospective review aims to determine the accuracy of CT in identifying true osteolysis in a cohort of long-term third generation ceramic-on-ceramic uncemented hip arthroplasties in our department. Pelvic CT scans were performed on the first 27 patients from a cohort of 301 patients undergoing 15-year review with third generation alumina-alumina cementless THAs. The average follow-up was 15 years (15–17). The CT scans were reviewed against pre-operative and post-operative radiographs and reviewed by a second musculoskeletal specialist radiologist. Eleven of the CT scans were reported to show acetabular osteolysis, two reported osteolysis or a possible pre-existing cyst and one reported a definitive pre-existing cyst. After review of previous imaging including pre-operative radiographs, eleven of the thirteen patients initially reported to have osteolysis were found to have pre-existing cysts or geodes in the same size and position as the reported osteolysis, and a further patient had spot-welds with stress-shielding. One patient with evidence of true osteolysis awaits aspiration or biopsy to determine if he has evidence of ceramic wear or metallosis. Reports of osteolysis on CT should be interpreted with care in modern ceramic-on-ceramic THA to prevent unnecessary revision. Further imaging and investigations may be necessary to exclude other conditions such as geodes, or stress shielding which are frequently confused with osteolysis on CT scans