During revision total knee arthroplasty (rTKA), proximal tibial bone loss is frequently encountered and can result in a less-stable bone-implant fixation. A 3D printed titanium alloy (Ti6Al4V) revision augment that conforms to the irregular shape of the proximal tibia was recently developed. The purpose of this study was to evaluate the fixation stability of rTKA with this augment in comparison to conventional cemented rTKA. Eleven pairs of thawed fresh-frozen cadaveric tibias (22 tibias) were potted in custom fixtures. Primary total knee arthroplasty (pTKA) surgery was performed on all tibias. Fixation stability testing was conducted using a three-stage eccentric loading protocol. Static eccentric (70% medial/ 30% lateral) loading of 2100 N was applied to the implants before and after subjecting them to 5×103 loading cycles of 700 N at 2 Hz using a joint motion simulator. Bone-implant micromotion was measured using a high-resolution optical system. The pTKA were removed. The proximal tibial bone defect was measured. One tibia from each pair was randomly allocated to the experimental group, and rTKA was performed with a titanium augment printed using selective laser melting. The contralateral side was assigned to the control group (revision with fully cemented stems). The three-stage eccentric loading protocol was used to test the revision TKAs. Independent t-tests were used to compare the micromotion between the two groups. After revision TKA, the mean micromotion was 23.1μm ± 26.2μm in the control group and 12.9μm ± 22.2μm in the experimental group. There was significantly less micromotion in the experimental group (p= 0.04). Prior to revision surgery, the control and experimental group had no significant difference in primary TKA micromotion (p= 0.19) and tibial bone loss (p= 0.37). This study suggests that early fixation stability of revision TKA with the novel 3D printed titanium augment is significantly better then the conventional fully cemented rTKA. The early press-fit fixation of the augment is likely sufficient for promoting bony ingrowth of the augment in vivo. Further studies are needed to investigate the long-term in-vivo fixation of the novel 3D printed augment

Introduction. In revision TKA, the management of bone loss depends on location, type, and extent of bony deficiency. Treatment strategies involve cement filling, bone grafting and augments. On the market several solutions are currently available, differing for their shape, thickness and material. While the choice of the shape and the thickness is mainly dictated by the bone defect, no explicit guideline is currently available to describe the best choice of material to be selected for a specific clinical situation. However, the use of different materials could induce different response in term of bone stress and thus changes in implant stability that could worsen long-term implant performance. For these reasons, an investigation about the changes in bone stress in the femur and in the tibia when augments, with different materials and thicknesses was performed. Methods. Different configurations have been separately considered including proximal tibial, distal or/and posterior femoral augments with a thickness of 5, 10 and 15 mm. Apart the control, in which no augments were used, but only the TKA is considered, the augment in all the other configurations were considered made by three different materials: bone cement, to simulate cement filling, tantalum trabecular metal and conventional metal (titanium for the tibia and CoCr for the femoral augments). Each configuration was inserted on a lower leg model including a cruciate-retaining total knee arthroplasty and analyzed by means of finite element analysis applying the max force achieved during walking. The bone stress was investigated in the medial and lateral region of interest close to the augment (with a bone thickness of 10 mm) and in an additional bone region of interest of 50 mm thickness. The bone stress have been compared among the different models and also with respect to the control model. Results. In general, the use of an augment induces a change in bone stress, especially in the region close to the bone cuts. The stiffness of the augment must be as close as possible to the one of the bone. Cement has the best results in terms of bone stress, however, it is only suitable for extremely small defects. Tantalum trabecular metal has results very close to cement and it could be consider a good alternative to cement for any size of defect. Metal (both titanium and CoCr) has the least satisfying results inducing the highest change in bone stress with respect the control. Conclusions. Tibial and femoral bone augments are adopted in case of bone defects that could be present during a revision knee replacement. Several solutions are available on the market in different shapes and materials. However, very few studies are reported to provide possible guidelines. The results of this study demonstrate that material stiffness of the augment must be as close as possible to the one of the bone to achieve the best results

Background. Total shoulder arthroplasty is technically demanding in regards to implantation of the glenoid component, especially in the setting of increased glenoid deformity and posterior glenoid wear. Augmented glenoid implants are an important and innovative option; however, there is little evidence accessible to surgeons to guide in the selection of the appropriate size augmented glenoid. Methods. Solid computer models of a commercially available augmented glenoid components (+3, +5, +7) contained within the software allowed for placement of the best fit glenoid component within the 3D reconstruct of each patient's scapula. Peg perforation, amount of bone reamed and amount of medialization were recorded for each augment size. Results. There was strong correlation between the medialization of the joint line and the glenoid retroversion for each augmented component (R. 2. of 0.785 for the +3 augment, an R. 2. of 0.792 for the +5 component, and an R. 2. of 0.701 for the +7 component). The range of retroversion that restored anatomic joint line using the +3 augmented glenoid was −3° to −17°, −5° to −24° using the +5 augmented glenoid, and −9° to −31° for a +7 augmented glenoid. Conclusions. Our results provide a general guideline for clinicians to select an appropriate sized augmented glenoid implant based on range of glenoid retroversion that can be corrected to restore the native joint line and minimize peg perforation. There was a strong correlation between glenoid retroversion and medialization for all augment sizes supporting the recommendation for glenoid retroversion as the primary guide in selecting the amount of augmentation

The amount of bone loss due to implant failure, loosening, or osteolysis can vary greatly and can have a major impact on reconstructive options during revision total knee arthroplasty (TKA). Massive bone loss can threaten ligamentous attachments in the vicinity of the knee and may require use of components with additional constraint to compensate for associated ligamentous instability. Classification of bone defects can be helpful in predicting the complexity of the reconstruction required and in facilitating pre-operative planning and implant selection. One very helpful classification of bone loss associated with TKA is the Anderson Orthopaedic Research Institute (AORI) Bone Defect Classification System as it provides the means to compare the location and extent of femoral and tibial bone loss encountered during revision surgery. In general, the higher grade defects (Type IIb or III) on both the femoral and tibial sides are more likely to require stemmed components, and may require the use of either structural graft or large augments to restore support for currently available modular revision components. Custom prostheses were previously utilised for massive defects of this sort, but more recently have been supplanted by revision TKA component systems with or without special metal augments or structural allograft. Options for bone defect management are: 1) Fill with cement; 2) Fill with cement supplemented by screws or K-wires; 3) Morselised bone grafting (for smaller, especially contained cavitary defects); 4) Small segment structural bone graft; 5) Impaction grafting; 6) Large prosthetic augments (cones); 7) Massive structural allograft-prosthetic composites (APC); 8) Custom implants. Maximizing support on intact host bone is a fundamental principle to successful reconstruction and frequently requires extending fixation to the adjacent diaphysis. Pre-operative planning is facilitated by good quality radiographs, supplemented on occasion by additional imaging such as CT. Fluoroscopically controlled x-ray views may assist in diagnosing the loose implant by better revealing the interface between the implant and bone and can facilitate accurate delineation of the extent of bone deficiency present. Part of the pre-operative plan is to ensure adequate range and variety of implant choices and bone graft resources for the planned reconstruction allowing for the potential for unexpected intra-operative findings such as occult fracture through deficient periprosthetic bone. Reconstruction of bone deficiency following removal of the failed implant is largely dictated by the location and extent of bone loss and the quality of bone that remains. While massive bone loss may compromise ligamentous attachment to bone, in the majority of reconstructions the degree of implant constraint needed for proper balancing and restoration of stability is independent of the bone defect. Thus some knees with minimal bone deficiency may require increased constraint due to the status of the soft tissues while others involving very large bone defects especially of the cavitary sort may be well managed with minimal constraint

The amount of bone loss due to implant failure, loosening, or osteolysis can vary greatly and can have a major impact on reconstructive options during revision total knee arthroplasty (TKA). Massive bone loss can threaten ligamentous attachments in the vicinity of the knee and may require use of components with additional constraint to compensate for associated ligamentous instability. Classification of bone defects can be helpful in predicting the complexity of the reconstruction required and in facilitating preoperative planning and implant selection. One very helpful classification of bone loss associated with TKA is the Anderson Orthopaedic Research Institute (AORI) Bone Defect Classification System as it provides the means to compare the location and extent of femoral and tibial bone loss encountered during revision surgery. In general, the higher grade defects (Type IIb or III) on both the femoral and tibial sides are more likely to require stemmed components, and may require the use of either structural graft or large augments to restore support for currently available modular revision components. Custom prostheses were previously utilised for massive defects of this sort, but more recently have been supplanted by revision TKA component systems with or without special metal augments or structural allograft. Options for bone defect management are: 1) Fill with cement; 2) Fill with cement supplemented by screws or K-wires; 3) Morselised bone grafting (for smaller, especially contained cavitary defects); 4) Small segment structural bone graft; 5) Impaction grafting; 6) Large prosthetic augments (cones); 7) Massive structural allograft-prosthetic composites (APC); 8) Custom implants. Maximising support on intact host bone is a fundamental principle to successful reconstruction and frequently requires extending fixation to the adjacent diaphysis. Preoperative planning is facilitated by good quality radiographs, supplemented on occasion by additional imaging such as CT. Fluoroscopically controlled x-ray views may assist in diagnosing the loose implant by better revealing the interface between the implant and bone and can facilitate accurate delineation of the extent of bone deficiency present. Part of the preoperative plan is to ensure adequate range and variety of implant choices and bone graft resources for the planned reconstruction allowing for the potential for unexpected intraoperative findings such as occult fracture through deficient periprosthetic bone. Reconstruction of bone deficiency following removal of the failed implant is largely dictated by the location and extent of bone loss and the quality of bone that remains. While massive bone loss may compromise ligamentous attachment to bone, in the majority of reconstructions the degree of implant constraint needed for proper balancing and restoration of stability is independent of the bone defect. Thus some knees with minimal bone deficiency may require increased constraint due to the status of the soft tissues while others involving very large bone defects especially of the cavitary sort may be well managed with minimal constraint

The amount of bone loss due to implant failure, loosening, or osteolysis can vary greatly and can have a major impact on reconstructive options during revision total knee arthroplasty. Massive bone loss can threaten ligamentous attachments in the vicinity of the knee and may require use of components with additional constraint to compensate for associated ligamentous instability. Classification of bone defects can be helpful in predicting the complexity of the reconstruction required and in facilitating preoperative planning and implant selection. One very helpful classification of bone loss associated with TKA is the Anderson Orthopaedic Research Institute (AORI) Bone Defect Classification System. This system provides the means to compare the location and extent of femoral and tibial bone loss encountered during revision surgery. In general, the higher grade defects (Type IIb or III) on both the femoral and tibial sides are more likely to require stemmed components, and may require the use of either structural graft or large augments to restore support for currently available modular revision components. Custom prostheses were previously utilised for massive defects of this sort, but more recently have been supplanted by revision TKA component systems with or without special metal augments or structural allograft. Options for bone defect management are as follows: 1) fill with cement, 2) fill with cement supplemented by screws or K-wires, 3) Morsellised bone grafting (for smaller, especially contained cavitary defects), 4) Small segment structural bone graft, 5) Impaction grafting, 6) Large prosthetic augments (cones), 7) Massive structural allograft-prosthetic composites (APC), 8) Custom implants. It is very helpful for revision surgeons to have a variety of reconstructive options available, even despite a well thought-out preoperative plan. Preoperative planning is important but the plan that results may require alteration during the course of the surgery to accommodate bone defects which are either less or more severe than thought pre-operatively, and to adjust to variable quality and extent of host bone remaining, as this provides the mechanical platform for the reconstruction. Maximising support on intact host bone is a fundamental principle to successful reconstruction and frequently requires extending fixation to the adjacent diaphysis. Bone defect management during revision total knee arthroplasty can provide a wide range of challenges from relatively trivial problems with small defects manageable with cement or small amounts of cancellous graft to massive deficiencies that may defy reconstruction except with allograft prosthetic components or large segmental replacing tumor-type implants. The more common Type II deficiencies increasingly seen in the context of particulate driven osteolysis demand a wide range of implant and bone graft options so that an individualised reconstruction can be accomplished for that particular patient based on bone defect size, location, quality of bone remaining, ligamentous status, and anticipated patient demands

The major causes of revision total knee are associated with some degree of bone loss. The missing bone must be accounted for to insure success of the revision procedure, to achieve flexion extension balance, restore the joint line to within a centimeter of its previous level, and to assure a proper sizing especially the anteroposterior diameter of the femoral component. In recent years, clinical practice has evolved over time with a general move away from a structural graft with an increase in utilisation of metal augments. Alternatives include cement with or without screw fixation, rarely, with the most common option being the use of metal wedges. With the recent availability of highly porous augments, the role of metal augmentation has increased. Bone graft is now predominantly used in particulate form for contained defects with more limited use of structural graft. The role of the allograft-prosthetic composite has become more limited. For the elderly with osteopenia and massive bone loss, complete metal substitution with an oncology prosthesis has become more common. The degree of bone loss is a major determinant of the management strategy. For contained defects less than 5 mm, cement alone, with or without screw supplementation, may be adequate. For greater than 5 mm, morselised graft is frequently used. For uncontained defects of up to 15 mm or more, metal augmentation is the first choice. Bone graft techniques can be utilised in this setting, however, these are more time consuming and technically demanding with little demonstrated advantage. For larger, uncontained defects, newer generation highly porous augments and step wedges are useful. Large contained defects can be dealt with utilising impaction grafting, similar to the hip impaction grafting technique. Massive distal defects are expeditiously managed with oncology defects in the case of periprosthetic fracture and/or massive osteolysis particularly when combined with osteopenia in an elderly, low demand patient. Surgeons must be familiar with an array of techniques in order to effectively deal with the wide spectrum of bone defects encountered during revision total knee arthroplasty

Massive bone loss on both the femur and tibia during revision total knee arthroplasty (TKA) remains a challenging problem. Multiple solutions have been proposed for small osseous defects, including morselised cancellous bone grafting, small-fragment structural allograft, thicker polyethylene inserts, and the use of modular augments attached to revision prosthetic designs. Large osseous defects can be treated with structural allografts, impaction bone-grafting with or without mesh augmentation, custom prosthetic components, and specialised hinged knee components. The metaphyseal area of the distal femur and proximal tibia is a particularly attractive option during revision TKA given that it is usually undamaged and well-vascularised. While multiple reconstructive options have been recommended, porous tantalum metaphyseal cones have the advantage of improved biologic fixation because of their high porosity (75–80%), interconnected pore space, and low modulus of elasticity (3 MPa) similar to that of cancellous bone. Such features allow tantalum cones to fill bone defects while tolerating physiological loads. Indications for porous tantalum metaphyseal cones include patients with Anderson Orthopaedic Research Institute Type 2B or greater defects. The surgical technique is simpler than structural allograft reconstructions with decreased preparation time, resulting in a possible decrease in infection rates. The modularity of porous tantalum metaphyseal cones also allows the surgeon to choose a size and position that best fits the individual defect encountered. Moreover, tantalum cones can be used with several revision systems. Short-term clinical follow up indicates that porous tantalum metaphyseal cones effectively provide structural support with the potential for long-term biologic fixation and durable reconstructions

Purpose:. To examine the performance of a novel blood plasma-based bone putty for augmenting the treatment of open tibia fractures. The putty was manufactured from pooled blood plasma and contains a concentration of both plasma and platelet-derived regenerative factors. Based on clinical reports of the use of autologous platelet-rich plasma to treat injuries, we hypothesized that the putty would accelerate healing of fractures and surrounding soft tissues. Methods:. Two-arm, randomized controlled study including 20 treatment patients and 10 controls. Follow-up examinations occurred at 14, 30, 60, 90, 180, and 365 days. The product was provided in a syringe containing 3 cc of putty in a double-pouched, sterile box. The putty was placed at the fracture site during open fracture reduction and mechanical stabilization. Results:. Both treatment and control groups were well balanced with a mean age of 35. Seventy percent were Gustillo IIIA and IIIB injuries, 67% were active smokers, and 70% received external fixation. No adverse events related to the use of the putty were noted. The use of the putty significantly reduced infections at 90 days (p = 0.002), accelerated bone bridging at 90 and 180 days, and provided more rapid wound closure at 30 days. In the subset of patients with IIIA/IIIB injuries, the putty group demonstrated more significantly reduced infections (p = 0.0007), with accelerated bone healing and wound closure approaching statistical significance. There were statistically fewer adverse events with the putty (42.1%) compared to controls (80.0%). Conclusions:. The potential for using a concentration of natural plasma and platelet-derived regenerative factors to augment the healing of traumatic injuries makes this first-in-man study relevant and exciting. The putty performed as expected, promoting more rapid healing of both fractures and wounds. The dramatic reduction in infections was unanticipated and is likely related to antimicrobial peptides in plasma and platelets

Introduction. Surgeons are often confronted with large amounts of bone loss during the revision of total hip prostheses. Regularly, porous metals are applied to reconstruct the missing bone. Rapid and extensive bone infiltration into the implant's pores is essential to obtain strong and durable biological fixation. Today, specialised layered manufacturing techniques provide the flexibility to produce custom-made metallic implants with a personalized external shape and a well-controlled internal network of interconnected pores. In this study, bone ingrowth in porous titanium structures that were manufactured by selective laser melting (SLM) was evaluated in an in vivo goat model. Methods. Cylindrical Ti6Al4V constructs (Ø8mm × 14mm, porosity 75%) with or without hydroxyapatite coating were implanted in six Saanen goats. Three holes were drilled in the subchondral bone of each tibia and femur. Constructs were inserted into the holes in a press-fit manner. Resonance frequency analysis was used to measure construct stability. At 3, 6 and 9 weeks after surgery, fluorochrome labels were injected. After 6 and 12 weeks, samples were explanted. Some samples were scanned with micro-CT and subsequently sectioned for histological analysis. The others were used for pull-out tests. Results. Resonance frequency analysis indicated a noticeable increase in implant stability. Evaluation of micro-CT and histological data showed bone ingrowth for all goats at 6 and 12 weeks. Most bone ingrowth occurred during the first 6 weeks, which was followed by a slight increase between week 6 and 12. Fluorochrome labeling confirmed these results. Pull-out tests showed an increased fixation at the bone-implant interface. Conclusion. Porous titanium structures manufactured by SLM have good osseointegration characteristics. As custom-made bone augments, they provide a promising approach to the reconstruction of severe bone defects

Cement-induced thermal osteonecrosis is well documented, as is the potential for nerve injury from thermal energy. Cement is often used to augment fixation following excision of humeral metastases. Porcine femurs were used as a model. We sought to find out the maximum temperatures that would be reached in various parts of the bone during the cement setting process, to explore what negative effects this might have on neighbouring bone and nerve. A 12mm by 12mm window was cut from 12 porcine femoral shafts, and Palacos R+D cement injected into the defect. As cement set, bone surface temperature was measured using infra-red thermal imaging and thermocouples used to measure temperatures at the bone-cement interface, 5mm from the cement bolus, 10mm from cement bolus and an area running around the shaft replicating radial nerve. Bone surface temperature rose to a maximum of 34.0 C (on average), and 32.9 C in the ‘radial nerve’ thermocouple. Notably, in two bones there were fractures during specimen preparation, and maximum temperatures in these two areas exceeded 41 degrees C. Average maximum temperatures were 58.1 C, 36.5 C and 30.1 C at the bone cement interface, 5mm and 10mm from the cement bolus respectively

Purpose

The aim of this study was to report the outcomes of a series of patients with clavicle fracture non-union who had undergone open reduction and internal fixation using a contoured locking plate without the use of distant bone graft.

Abstract. Background. The gold standard treatment for Anterior Cruciate Ligament injury is reconstruction (ACL-R). Graft failure is the concern and ensuring a durable initial graft with rapid integration is crucial. Graft augmentation with implantable devices (internal brace reinforcement) is a technique purported to reduce the risk of rupture and hasten recovery. We aim to compare the short-term outcome of ACL-R using augmented hamstring tendon autografts (internally braced with neoligament) and non-augmented hamstring autografts. Methods. This was a retrospective cohort study comparing augmented and non-augmented ACL-R. All procedures were performed in a single centre using the same technique. The Knee injury and Osteoarthritis Outcome Score [KOOS] was used to assess patient-reported outcomes. Results. There were 70 patients in the augmented and 111 patients in the control group. Mean graft diameter in the augmented group was 8.82mm versus 8.44mm in the non-augmented. Six strand graft was achievable in 73.5% of the augmented group compared to 33% in the non-augmented group. Two graft failures were reported in the non-augmented group and none in the augmented group. Patient satisfaction rates were higher in the augmented group. There was a statistically insignificant improvement in the postoperative KOOS in the augmented group compared to the non-augmented group (p 0.6). Irrespective of augmentation status, no correlation was found between the functional score and age, or femoral tunnel width. Conclusion. Augmented ACL-R may achieve superior graft diameters, lower failure rates and better patient reported outcomes when compared to nonaugmented ACL-R. Prospective trials are needed to examine this further

Abstract. Background. The gold standard treatment for Anterior Cruciate Ligament injury is reconstruction (ACL-R). Graft augmentation with suture tape (internal brace) are techniques purported to reduce the risk of rupture and hasten recovery. Our aim was to assess the short-term outcome of ACL-R using fibre tape augmented and non-augmented hamstring tendon grafts. Methods. This was a retrospective comparative study looking at augmented and non-augmented ACL-R. All procedures were performed by a single surgeon in a single centre using the same technique. The Knee injury and Osteoarthritis Outcome Score [KOOS] was used to assess patient-reported outcomes. Results. There were 72 patients in the augmented and 132 patients in the control group. Confounding factors were comparable in both groups. The mean graft diameter in the augmented group was 8.81mm versus 8.01mm in the non-augmented. Six strand graft was achievable in 71% of the augmented group compared to 62.5% in the non-augmented group. Two graft failures reported in the non-augmented group and none in the augmented group. The average 14-month postoperative KOOS in the augmented group was 90.5 compared to an average 30-month score of 82.5 in the non-augmented group, which is statistically significant. Conclusion. Augmented ACL-R demonstrate statistically significant better patient-reported outcomes compared to the nonaugmented group. Graft failure rates may also be lower in augmented ACL-R

This paper presents an ongoing review of the use of a wedge-shaped porous metal augments in the shoulder to address glenoid retroversion as part of anatomical total shoulder arthroplasty (aTSA). Seventy-five shoulders in 66 patients (23 women and 43 men, aged 42 to 85 years) with Walch grade B2 or C glenoids underwent porous metal glenoid augment (PMGA) insertion as part of aTSA. Patients received either a 15º or 30º PMGA wedge (secured by screws to the native glenoid) to correct excessive glenoid retroversion before a standard glenoid component was implanted using bone cement. Neither patient-specific guides nor navigation were used. Patients were prospectively assessed using shoulder functional assessments (Oxford Shoulder Score [OSS], American Shoulder and Elbow Standardized Shoulder Assessment Form [ASES], visual analogue scale [VAS] pain scores and forward elevation [FE]) preoperatively, at three, six, and 12 months, and yearly thereafter, with similar radiological surveillance. Forty-nine consecutive series shoulders had a follow-up of greater than 24 months, with a median follow-up of 48 months (range: 24–87 months). Median outcome scores improved for OSS (21 to 44), ASES (24 to 92), VAS (7 to 0), and FE (90º to 140º). Four patients died, but no others were lost to follow-up. Apart from one infection at 18 months postoperatively and one minor peg perforation, there were no complications, hardware failures, implant displacements, significant lucency or posterior re-subluxations. Radiographs showed good incorporation of the wedge augment with correction of glenoid retroversion from median 22º (13º to 46º) to 4º. All but four glenoids were corrected to within the target range (less than 10º retroversion). The porous metal wedge-shaped augments effectively addressed posterior glenoid deficiency as part of aTSA for rotator cuff intact osteoarthritis, producing satisfactory clinical outcomes with no signs of impending future failure

Augmented reality simulators offer opportunities for practice of orthopaedic procedures outside of theatre environments. We developed an augmented reality simulator that allows trainees to practice pinning of paediatric supracondylar humeral fractures (SCHF) in a radiation-free environment at no extra risk to patients. The simulator is composed of a tangible child's elbow model, and simulated fluoroscopy on a tablet device. The treatment of these fractures is likely one of the first procedures involving X-ray guided wire insertion that trainee orthopaedic surgeons will encounter. This study aims to examine the extent of improvement simulator training provides to real-world operating theatre performance. This multi-centre study will involve four cohorts of New Zealand orthopaedic trainees in their SET1 year. Trainees with no simulator exposure in 2019 - 2021 will form the comparator cohort. Trainees in 2022 will receive additional, regular simulator training as the intervention cohort. The comparator cohort's performance in paediatric SCHF surgery will be retrospectively audited using routinely collected operative outcomes and parameters over a six-month period. The performance of the intervention cohorts will be collected in the same way over a comparable period. The data collected for both groups will be used to examine whether additional training with an augmented reality simulator shows improved real-world surgical outcomes compared to traditional surgical training. This protocol has been approved by the University of Otago Health Ethics committee, and the study is due for completion in 2024. This study is the first nation-wide transfer validity study of a surgical simulator in New Zealand. As of September 2022, all trainees in the intervention cohort have been recruited along with eight retrospective trainees via email. We present this protocol to maintain transparency of the prespecified research plans and ensure robust scientific methods. This protocol may also assist other researchers conducting similar studies within small populations

The Adams-Berger reconstruction is an effective technique for treating distal radioulnar joint (DRUJ) instability. Graft preparation techniques vary amongst surgeons with insufficient evidence to support one technique over another. Our study evaluated the biomechanical properties of four graft preparation techniques. Extensor tendons were harvested from fresh frozen porcine trotters obtained from a local butcher shop and prepared in one of three configurations (n=5 per group): tendon only; tendon prepared with non-locking, running suture (2-0 FiberLoop, Arthrex, Naples, FL) spaced at 6 mm intervals; and tendon prepared with suture spaced at 12 mm intervals. A fourth configuration of suture alone was also tested. Tendons were allocated in a manner to ensure comparable average diameters amongst groups. Biomechanical testing occurred using custom jigs simulating radial and ulnar tunnels attached to a Bose Electroforce 3510 mechanical testing machine (TA Instruments). After being woven through the jigs, all tendons were sutured end-to-end with 2-0 PROLENE suture (Ethicon). Tendons then underwent a staircase cyclic loading protocol (5-25 Newtons [N] at 1 hertz [Hz] for 1000 cycles, then 5-50 N at 1 Hz for 1000 cycles, then 5-75 N at 1 Hz for 1000 cycles) until graft failure; if samples did not fail during the protocol, they were then loaded to failure. Samples were visually inspected for mode of failure after the protocol. A one-way analysis of variance was used to compare average tendon diameter; post-hac Tuhey tests were used to compare elongation and elongation rate. Survival to cyclic loading was analyzed using Kaplan-Meier survival curves with log rank. Statistical significance was set at a = 0.05. The average tendon diameter of each group was not statistically different [4.17 mm (tendon only), 4.33 mm (FiberLoop spaced 6 mm), and 4.30 mm (FiberLoop spaced 12 mm)]. The average survival of tendon augmented with FiberLoop was significantly higher than tendon only, and all groups had significantly improved survival compared to suture only. There was no difference in survival between FiberLoop spaced 6 mm and 12 mm. Elongation was significantly lower with suture compared to tendon augmented with FiberLoop spaced 6 mm. Elongation rate was significantly lower with suture compared to all groups. Modes of failure included rupture of the tendon, suture, or both at the simulated bone and suture and/or tendon interface, and elongation of the entire construct without rupture. In this biomechanical study, augmentation of porcine tendons with FiberLoop suture spaced at either 6 or 12 mm for DRUJ reconstruction significantly increased survival to a staircase cyclic loading protocol, as suture material was significantly stiffer than any of the tendon graft configurations

Problem. Total hip replacement (THA) is among the most common and highest total spend elective operations in the United States. However, up to 7% of patients have 90-day complications after surgery, most frequently joint dislocation that is related to poor acetabular component positioning. These complications lead to patient morbidity and mortality, as well as significant cost to the health system. As such, surgeons and hospitals value navigation technology, but existing solutions including robotics and optical navigation are costly, time-consuming, and complex to learn, resulting in limited uptake globally. Solution. Augmented reality represents a navigation solution that is rapid, accurate, intuitive, easy to learn, and does not require large and costly equipment in the operating room. In addition to providing cutting edge technology to specialty orthopedic centers, augmented reality is a very attractive solution for lower volume and smaller operative settings such as ambulatory surgery centers that cannot justify purchases of large capital equipment navigation systems. Product. HipInsight™ is an augmented reality solution for navigation of the acetabular component in THA. HipInsight is a navigation solution that includes preoperative, cloud based surgical planning based on patient imaging and surgeon preference of implants as well as intraoperative guidance for placement of the acetabular component. Once the patient specific surgical plan is generated on the cloud-based planning system, holograms showing the optimal planned position of the acetabular component are exported in holographic format to a Microsoft HoloLens 2™, which the surgeon wears during placement of the acetabular component in total hip arthroplasty. The pelvis is registered using the HipXpert™ mechanical registration device, which takes 2–3 minutes to dock in the operating room. The surgeon then is able to view the patient's anatomy and optimal placement of the acetabular component under the skin in augmented reality. The surgeon then aligns the real cup impactor with the augmented reality projection of the cup impactor resulting in precise placement of the cup. Timescales. HipInsight was FDA cleared on January 28, 2021 for intraoperative use for placement of the acetabular component in total hip arthroplasty. The first case was performed in February 2021, and the product was launched to a select group of orthopedic surgeons in March 2021. Funding. HipInsight has been self-funded to date, and is beginning to engage in discussions to raise capital for a rapidly scaling commercial launch

INTRODUCTION. 3D preoperative planning software for anatomic and reverse total shoulder arthroplasty (ATSA and RTSA) provides additional insight for surgeons regarding implant selection and placement. Interestingly, the advent of such software has brought previously unconsidered questions to light on the optimal way to plan a case. In this study, a survey of shoulder specialists from the American Shoulder and Elbow Society (ASES) was conducted to examine thought patterns in current glenoid implant selection and placement. METHODS. 172 ASES members completed an 18-question survey on their thought process for how they select and place a glenoid implant for both ATSA and RTSA procedures. Data was collected using a custom online Survey Monkey survey. Surgeon answers were split into three cohorts based on their responses to usage of 3D preoperative planning software: high users, seldom users, and non-users. Data was analyzed for each cohort to examine differences in thought patterns, implant selection, and implant placement. RESULTS. 76 surgeons were grouped into the high user cohort, 66 into the seldom user cohort, and 30 into the non-user cohort. 61.9% of high users and 74.1% of seldom users performed >75 shoulder arthroplasties per year, whereas only 19.9% of non-users performed >75 arthroplasties per year (Figure 1). When questioned on glenoid implant type selection (augmented vs. non-augmented components), 80.3% of high users reported augment usage for both ATSA and RTSA, with using augments >45% of the time in 18.4% of ATSA cases and in 22.3% of RTSA cases. For seldom users, 80.3% reported augment usage in ATSA cases, and 70.3% in RTSA cases. Seldom users reported augment usage >45% of the time in 4.5% of ATSA cases and in 1.6% of RTSA cases. For non-preoperative planning users, 53.3% reported using augments in ATSA cases, and 48.3% for RTSA cases. Non-users used augmented glenoid components >45% of the time in 6.6% of ATSA cases and in 6.8% of RTSA cases. For resultant implant superior inclination in RTSA, 40.8% of high users aim for 0° of inclination, followed by 31.8% for seldom users and 16.7% of non-users (Figure 2). CONCLUSION. The results of this study show that 3D preoperative planning software has an influence on the decision making process when planning a shoulder arthroplasty. High volume shoulder arthroplasty surgeons report higher preoperative planning software usage than low volume surgeons, suggesting the utility of such software. Augmented glenoid component usage for both ATSA and RTSA is also higher for surgeons that use preoperative planning software, which either suggests the utility of augmented glenoid components, or that the use of such software creates the perceived need for augmented glenoid components. Lastly, surgeons who preoperatively plan tend to orient their glenoid components differently, which could suggest either a better understanding of the anatomy through the use of the software, or an influence on mindset regarding implant orientation resulting from software usage. This highlights an area for future work that could correlate clinical outcome data to implant selection and placement to prove what is the optimal plan for a given patient. For any figures or tables, please contact the authors directly

INTRODUCTION. Porous metal bone fillers are frequently used to manage bony defects encountered in revision total knee arthroplasty (rTKA). Compared to structural graft, porous metal bone fillers have shown significantly lower loosening and failure rates potentially due to osseointegration and increased material strength [1]. The strength of porous metal bone fillers used in lower extremities is frequently assessed using compression/shear/torsion test methods, adapted from spine standards. However, these basic methods may lack clinical relevance, and do not provide any insight on the relationship between patient activity and anticipated prosthesis performance. The goal of this study was to evaluate the response of bone fillers under different activities of daily living, in order to define physiologically relevant worst case biomechanics for component evaluation. METHODS. A bone filler tibial augment is shown in Figure 1. A test construct for tibial augments (half-block each for medial and lateral sides) is shown in Figure 2, along with compatible rTKA components. An additional void in the bone was filled using bone cement. Loading was applied through the tibiofemoral contact patches created on polyethylene tibial insert. Loading was used for two activities of daily living; walking and deep knee bend [2–3]. During walking, the tibiofemoral contact patch on the anterior tibial post gets loaded due to femoral hyperextension with 1.2xbody weight (BW), whereas the medial and lateral condyles get loaded with 3xBW compressive load. For deep knee bend, only the condyles get loaded with 4.34xBW. Compared to walking, 45% higher compressive load magnitude in deep knee bend located further posterior was anticipated to create a larger bending moment and induce higher stress on the half augments. A finite element analysis (FEA) was performed by modeling this test construct with a medium size tibial augment. All components were modeled using linear elastic material properties. All interfaces, including the augment-bone interface (representing full bony ingrowth construct) were modeled using bonded contact. The inferior surface of the bone analogue was constrained. Linear static analyses were performed and peak von mises stress predicted in the tibial augments was compared between activities. RESULTS. Deep knee bend resulted in 31% higher stresses in the tibial augments than for walking. High von mises stresses were mostly predicted at the superior/posterior aspect of the internal side of the augment and in the corners of the cutouts. Figure 3 presents the von mises stresses in the tibial augments for both loading scenarios. DISCUSSION. This study revealed that the 45% increased posterior compressive load associated with deep knee bend is a more significant factor than the moment applied to the post during walking gait for a hyperextended knee, when considering the stress in bone filler augments in revision TKA. The stress in the augments can depend on multiple factors and the proposed FEA method can be used to compare stresses in different porous material bone fillers to determine worst case for assessing its strength