Purpose. Femoral shaft fractures are routinely treated using antegrade intramedullary nailing under fluoroscopic guidance. Malreduction is common and can be due to multiple factors. Correct entry point identification can help minimize malreduction and the risk of iatrogenic fracture. This study aims to compare landmark identification used to guide nail entry, the piriformis fossa (PF) and the trochanteric tip (T), via computer navigation and conventional fluoroscopy. Method. The location of the PF and T were digitized under direct visualization with a three-dimensional scribe on ten, fresh-frozen cadaveric right femora (two male, eight female) by three fellowship trained orthopaedic surgeons. To estimate inter- and intraobserver reliability of the direct measurements, an intraclass correlation coefficient was calculated with a minimum of two weeks between measurements. Under navigation, each specimen was draped and antero-posterior (AP) and lateral radiographs of the proximal femur were taken with a c-arm and image intensifier. The c-arm was positioned in a neutral position (0 for AP, 90 for lateral) and rotated in 5 increments, yielding a range of acceptable images. Images, in increments of 5, within the AP range (with a neutral lateral) were loaded into a navigation system (Stryker, MI). A single surgeon digitized the T and PF directly based on conventional fluoroscopy, and again directed by navigation, yielding two measurements per entry point per specimen. This was repeated for the lateral range. Hierarchical linear modelling and a Wilcox rank test were used to determine differences in accuracy and precision, respectively, in the identification of PF and T using computer navigation vs. conventional fluoroscopy. Results. The average range of suitable images for both the AP and lateral images was 29 (range of 25 to 30). The location of the PF and T was found to be reliable for a single observer (0.98 and 0.99) and between observers (0.96 and 0.93). Similar accuracy was found in identifying PF under navigation and fluoroscopy (0.05 to 1.4 cm and 0.1 to 1.5 cm respectively, p = 0.26), whereas improved accuracy was found for T using fluoroscopy (0.07 to 2.5 cm) as compared to navigation (0.2 to 2.2 cm, p < 0.001). For both the PF and T, the navigation-based points had greater precision than those selected by fluoroscopy alone (p = 0.001 and p = 0.024). Conclusion. The ideal entry point, under direct visualization, was highly repeatable, indicating that the surgeons could identify their targeted point of entry for both the PF and T. However, there is an arc of approximately 30, through which acceptable AP and lateral images can be obtained. Throughout this range, the location of the PF and T can vary up to 1.5 and 2 cm, respectively. Navigation was less accurate than fluoroscopy in the T selection, yet had greater precision for both points. Thus, while navigation may decrease accuracy in selection of the T, it is more repeatable overall and equally accurate in selecting the PF

To introduce a new robot-assisted surgical system for spinal posterior fixation which called TiRobot, based on intraoperative three-dimensional images. TiRobot has three components: the planning and navigation system, optical tracking system and robotic arm system. By combining navigation and robot techniques, TiRobot can guide the screw trajectories for orthopedic surgeries. In this randomised controlled study approved by the Ethics Committee, 40 patients were involved and all has been fully informed and sign the informed consent. 17 patients were treated by free-hand fluoroscopy-guided surgery, and 23 patients were treated by robot-assisted spinal surgery. A total of 190 pedicle screws were implanted. The overall operation times were not different for both groups. None of the screws necessitated re-surgery for revised placement. In the robot-assisted group, assessment of pedicle screw accuracy showed that 102 of 102 screws (100%) were safely placed (<2 mm, category A+B). And mean deviation in entry point was 1.70 +/− 0.83mm, mean deviation in end point was 1.84 +/− 1.04mm. In the conventional freehand group, assessment of pedicle screw accuracy showed that 87 of 88 (98.9%) were safely placed (<2 mm, category A+B), 1 screw fall in category C, mean deviation in entry point was 3.73 +/− 2.28mm, mean deviation in end point was 4.11 +/− 2.31mm. This randomised controlled study verified that robot-assisted pedicle screw placement with real-time navigation is a more accuracy and safer method, and also revealed great clinical potential of robot-assisted surgery in the future

Anterior Cruciate Ligament (ACL) rupture is one of the commonest injuries in sports medicine. However, the rates of the reported graft re-rupture range from 2–10%, leading to around 3000 to 10000 revision ACL reconstructions in United States per annum. Inaccurate tunnel positions are considered to be one of the commonest reasons leading to failure and subsequent revision surgery. Additionally, there remains no consensus of the optimal position for ACL reconstructions. The positions of the bone tunnels in patients receiving ACL reconstruction are traditionally assessed using X-rays. It is well known that conventional X-ray is not a precise tool in assessing tunnel positions. Thus, there is a recent trend in using three-dimensional (3D) CT. However, routine CT carries a major disadvantage in terms of significant radiation hazard. In addition, it is both inconvenient and expensive to use CT as a regular assessment tools during the follow-up. The goal of the present work is to develop a novel 2D-3D registration method using single X-ray image and a surface model. By performing such registration for two post-operative X-rays, we can further calculate the 3D tunnel positions after ACL reconstructions. Our framework consists of five parts: (1) a surface model of the knee, (2) a 2D-3D registration algorithm, (3) a 3D tunnel position calculation, (4) a graphic user interface (GUI), and (5) a semi-transparency rendering. Among them, the crucial part is our 2D-3D registration method that estimates the relative position of the knee model in the imaging coordinate system. Once registered, the 3D position of an ACL tunnel in the knee model is calculated from the imaging geometry. The only interaction required is to mark the ACL tunnels on the X-rays through the GUI. We propose two 2D-3D registration methods. One is a contour-based method that uses pure geometric information. Most methods in this category accomplish the registration by extracting contours in X-rays, establishing their correspondences on the 3D model, and calculating the registration parameters. Unlike these methods, which need point-to-point correspondences, our method optimises the registration parameters in a statistical inference framework without giving or establishing point-to-point correspondences. Due to the use of the statistical inference, our method is robust to the spurs and broken contours that automatically extracted by the contour detector. The second method takes into account both the geometric shape of the object and the intensity property (intensity changes) of the image, where the intensity changes can be detected via image gradients. The use of gradient is based on the interpretation that two images are considered similar, if intensity changes occur at the same locations. The angles between the image gradients and the projected surface normals were used as a distance measure. The summation of the measures for all projected model points gives us the gradient term, which we multiply the contour-based measurement. Multiplication is preferred over addition because addition of the terms would require both terms to be normalised. To evaluate the feasibility of our methods, a simulation study was conducted using Digitally Reconstructed Radiographs (DRR) of a sawbone underwent a single-bundle ACL reconstruction performed by an experienced orthopedic surgeon. The real position of the bone tunnel entry point was obtained using the CT images, which were acquired using a custom-made well-calibrated cone-beam CT. The knee model was built by downsampling and smoothing the high-resolution CT reconstructions. It is important in our experiments to make the model different from the original reconstruction since this simulates the condition in which patient's CT is unavailable. Two DRRs generated from approximately anteroposterior and lateral viewpoints were used. For each DRR, 50 trials of 2D-3D registration were carried out for the femoral part using 50 different initialisations, which were randomly selected from the values independently and uniformly distributed within ±10 degrees and ±10 mm of the ground-truth. Compared with the ground-truth established using the CT images, our single image contour-based method achieved accurate estimations in rotations and in-plane translations, which were (−0.67±1.38, −0.98±0.84, −0.42±0.71) degrees and (0.11±0.26, −0.06±1.20) mm for the anteroposterior image, and (−0.78±0.76, −0.37±0.87, 0.70±0.88) degrees and (−0.14±0.22, 0.31±0.71) mm for the lateral one, respectively. The same experiments were also performed using the second method. However, it did not produce desirable results in our experiments. The tunnel entry point was then calculated using the averaged registration result of our contour-based method. The entry point of the tunnel was obtained with high accuracy of 1.25 mm distance error from the real position of the entry point. For the 2D-3D registration, the estimated off-plane translations showed relatively low accuracy. It is well known that the depth can be difficult to be accurately estimated using one single image. As the result showed, the accuracy in rotations and in-plane translations is more important for ACL tunnel position estimation in our framework. As for the image gradient, it is too sensitive to the small perturbation caused by image noises. A more robust way of integrating the gradient information into our contour-based method is required. We propose a novel approach for estimating the 3D position of bone tunnels in ACL reconstruction using two post-operative X-rays. It was tested in a sawbone study using DRRs. The most significant advantage of our approach is to potentially eliminate the necessity of acquiring a patient's CT. The success in developing and validating the proposed workflow will allow convenient and precise assessment of tunnel positions in ACL reconstruction with minimal risk of radiation hazard

Introduction. Hip resurfacing arthroplasty (HRA) is currently regaining positive attention as a treatment of osteoarthritis in young, active individuals[1]. The procedure is complex and has low tolerance for implant malpositioning [2]. ‘Precision tools', such as imageless navigation and patient specific instruments, have been developed to assist with implant positioning but have not been shown to be fully reliable [3]. The aim of this study is to present and validate the first step of novel quality control tool to verify implant position intra-operatively. We propose that, before reaming of the femoral head, a handheld structured light 3D scanner can be used to assess the orientation and insertion point of femoral guide wire. Methods. Guide wires were placed into the heads of 29 solid foam synthetic femora. A specially designed marker (two orthogonal parallelepipeds attached to a shaft) was inserted into the guide wire holes. Each bone (head, neck and marker) was 3D scanned twice (fig 1). The insertion point and guide wire neck angle were calculated from the marker's parameters. Reference data was acquired with an optical tracking system. The measurements calculated with the 3D scans were compared to the reference ones to evaluate the precision. The comparison of the test retest measurements done with the new method are used to evaluate intra-rater variability. Results. The difference between the entry point measured with the 3D scanner and the reference data was 1.68 mm (SD 2.23 mm). The difference of the measured guide wire axis and the reference axis is 2.44 degrees (SD 2.29). The intra-rater difference was 0.02 mm (SD 0.55mm, ICC 0.9995) for the entry point and 0.20 degrees (SD 0.20, ICC 0.9975) for the guide wire insertion axis. Conclusions. The results of this study indicate that a structured light based 3D scanning technology is accurate in assessing orientation and insertion point of the femoral guide wire during HRA. A small precision bias was identified and further work will need to investigate the cause. Also, inter-rater variability needs to be assessed. This simple verification tool can be used by any hip surgeon and will be most beneficial to those in low-volume centres or in training. It has a potential to be used during teaching and to decrease the learning curve through a self-feedback mechanism. Further studies could use the tool to asses final implant position and focus on other joint replacement procedures requiring high degree of accuracy

Cemented total hip arthroplasty (THA) has become an extremely successful operation with excellent long-term results. Although showing decreasing popularity in North America, it always remained a popular choice for the elderly patients in Europe and other parts of the world. Various older and recent studies presented excellent long-term results, for cemented fixation of the cup as well as the stem. Besides optimal component orientation, a proper cementing technique is of major importance to assure longevity of implant fixation. Consequently a meticulous bone bed preparation assures the mechanical interlock between the implant component, cement and the final bone bed. Preoperative steps as proper implant sizing/ templating, ensuring an adequate cement mantle thickness, and hypotensive anesthesia, minimising bleeding at the bone cement interface, are of major importance. First the fossa pyriformis should be clearly identified, including the posterolateral entry point of the prosthesis. The femoral neck cut is usually 1.5cm to 2cm above the minor trochanter, based on the preoperative planning and implant type. Opening of the canal is done with an awl or osteotome, followed by any blunt tipped instrument, to follow the intramedullary direction. A box osteotome opens the lateral portion of the femoral neck, gently to preserve as much cancellous bone as possible. Sequential broaching follows carefully and according to the planning, to ensure preservation of 2mm to 3mm cancellous bone for interdigitation. Some systems might require over-broaching by one size. Trialing is done with the broach. Following, irrigation using a long nozzle pulsatile lavage, reduces the chance for fat embolism. A cement restrictor is then placed 1.5cm to 2cm distal to the tip of the stem, to ensure an adequate cement mantle distally. A second complete pulsatile irrigation of the canal follows, to minimise bleeding, followed by a dry sponge. Cement mixing is vacuum based in the meantime, usually 60–80g. We prefer the use of low dose antibiotic laden cement in our set up. Two to three minutes after mixing, the cement is applied rapidly in a retrograde technique, with a cement gun placing the nozzle tip against the cement restrictor. The gun is “pushed” out during the application, rather than being withdrawn from the canal. Proximal pressurization is first done by thumb, then with a proximal seal for 1 minute. The stem is inserted slowly using steady manual pressure, in the center of the cement mantle, however should never be impacted. The stem is aligned with the previously defined lateral entry point and is held in position until the cement hardens. The desired outcome is a cement interdigitation into cancellous bone for 2mm to 3mm and an additional mantle of 2mm pure cement

Cemented total hip arthroplasty has become an extremely successful operation with excellent long term results. Although showing decreasing popularity in North America, it always remained a popular choice for the elderly patients in Europe and other parts of the world. Besides optimal component orientation, a proper cementing technique is of major importance to assure longevity of implant fixation. Consequently a meticulous bone bed preparation assures the mechanical interlock between the implant component, cement and the final bone bed. Cementing the acetabular side should include preservation of the transverse acetabular ligament and clear identification of the medial wall. Medialisation and deepening of the socket are important at reaming, to ensure a containment of the cup. The contact of the cup to cancellous bone should be maximised. Either smaller reamers or 4–6mm anchoring holes can be drilled to the superior sclerosis. Smaller defects can be curettage, while larger ones might require cancellous bone grafting. Of major importance is the thoroughly pulsatile jet lavage with saline to irrigate the cancellous bone bed, to reduce fat and blood lamination. After final irrigation, before cementation, dry sponges are slightly impacted into the cavity, to dry it out. Cementation usually requires 40g of high viscosity bone cement. Immediate pressurisation of the cement into the bone bed should start after a general application time in our institution between 2.5 to 3 minutes after mixing; with either a sterile glove filled with a sponge or designated company specific pressuriser. Sustained pressurisation should be done for 1 minute. The original cup should be 3–4mm smaller than the last reamer, to ensure circumferential cement mantle. Insertion principle includes medialisation first, followed by gradual angulation of the cup. In appropriate position, a balled pressuriser maintains pressure without further moving of the implant, until cement hardening. Remnant cement can be removed with osteotomes, while remaining osteophytes should be flush with implant. Femoral Side: First the fossa pyriformis should be clearly identified, including the posterolateral entry point of the prosthesis. The femoral neck cut is usually 1.5–2cm above the minor trochanter, based on the preoperative planning and implant type. Opening of the canal is done with an awl or osteotome, followed by any blunt tipped instrument, to follow the intramedullary direction. A box osteotome opens the lateral portion of the femoral neck, gently to preserve as much cancellous bone as possible. Sequential broaching follows carefully and according to the planning, to ensure preservation of 2–3mm cancellous bone for interdigitation. Some systems might require over-broaching by one size. Trialing is done with the broach. Following, irrigation using a long nozzle pulsatile lavage, reduces the chance for fat embolism. A cement restrictor is then placed 1.5–2cm distal to the tip of the stem, to ensure an adequate cement mantle distally. A second complete pulsatile irrigation of the canal follows, to minimise bleeding, followed by a dry sponge. Cement mixing is vacuum based in the meantime, usually 60–80g. We prefer the use of low dose antibiotic laden cement in our set up. Two to three minutes after mixing, the cement is applied rapidly in a retrograde technique with a cement gun, placing the nozzle tip against the cement restrictor. The gun is “pushed” out during the application, rather than being withdrawn from the canal. Proximal pressurisation is first done by thumb, then with a proximal seal for 1 minute. The stem is inserted slowly using steady manual pressure, in the center of the cement mantle, however, should never be impacted. The stem is aligned with the previously defined lateral entry point and is held in position until the cement hardens. The desired outcome is a cement interdigitation into cancellous bone for 2–3mm and an additional mantle of 2mm pure cement

The treatment for Humeral Supracondylar fractures in children is percutaneous fixation with Kirschner wires using a unilateral or crossed wire configuration. Capitellar entry point with divergent wires is thought crucial in the lateral entry approach. Crossed wire configuration carries a risk of Ulnar nerve injury. Our department had recorded a number of failures and this required review. A search was conducted for children with this injury and surgical fixation. A two year time frame was allocated to allow for adequate numbers. The hospitals radiography viewing system and patient notes were utilized to gather required information. 30 patients from 2–14 years all underwent surgery on the day of admission or the following day. 18 had sustained Gartland grade 3 or 4 injuries. Unilateral configuration was used in 10 cases; a loss of reduction was noted in 5 of these with one case requiring reoperation. Crossed wires were used in 20 cases with a loss of reduction in 1. Crossed wire configuration provides a more reliable fixation with a lower chance or re-operation. Our DGH policy now advises the use of this configuration. A small “mini-open” ulnar approach is utilized with visualization and protection of the nerve

Introduction. Appropriate prosthetic alignment is an important factor in maintaining stability and maximising the performance of the bearing after total hip replacement (THR). With a cementless component, the anteversion of the native femur has been shown to influence the anteversion of the prosthetic stem. However, the extent to which anteversion of a cementless stem can be adjusted from the native anteversion has seldom been reported. The aim of this study was to investigate the difference between native and stem anteversion with two different cementless stem designs. Method. 116 patients had 3-dimensional templating as part of their routine planning for THR (Optimized Ortho, Sydney). 96 patients from 3 surgeons (AS, JB, SM) received a blade stem (TriFit TS, Corin, UK) through a posterior approach. 18 patients received a fully HA-coated stem (MetaFix, Corin, UK) through a posterior approach by a single surgeon (WB). The anteversion of the native femoral neck was measured from a 3D reconstruction of the proximal femur. All patients received a post-operative CT scan which was superimposed onto the pre-op CT scan. The difference between native and achieved stem anteversion was then measured. As surgeons had differing philosophies around target stem anteversion, the differences amongst surgeons were also investigated. Results. On average, stems were implanted in less anteversion than native. The mean deviation between native and stem anteversion of the blade stems was −3.5° (−34.8° to 13.8°). The mean deviations of the three surgeons using the blade stem were −7.9° (−34.8° to 10.4°), −3.1° (−18.1° to 12.0°) and 2.7° (−8.9° to 13.8°). These were statistically significant, and represented a difference in philosophy around target anteversion amongst surgeons. The mean deviation between native and stem anteversion of the fully HA-coated stems was −6.5° (−24.6° to 9.2°). Conclusions. Cementless stem anteversion is not dictated by the native femoral anteversion. There were differences in target anteversion philosophies amongst surgeons and this was seen in the results. Surgical approach, proximal entry point, osteotomy angle, stem design and patient anatomy will all influence the ability to dictate cementless stem anteversion. The effect of these variables are the subject of on-going work

Introduction. PSI technology have proved helpful in difficult primary Total Knee Replacement. However applying it to revision was impossible due to multiple factor. To Start with the landmark We usually destroy it. There is an extensive damage at the bone at the epiphysis, the implant prevent an accurate visualization and debridement usually change the surface of the bone as well which make applying the psi dyed impossible, we are proposing a new way of using psi in revision where we don't depend on the all masses adjusted in primary. However we depend on the metaphysical area of the bone. Material & method. We have reviewed 56 MRI & CT scans for cases posted for revision and showed clearly that in spite of the extensive bony destruction and metal presence the MRI / CT scan we were able to visualize well the metaphysical area in the intramedullary canal in both tibial and femoral we have established a special external guide that depends on the outside surface of the metaphysis of the femur. We have tried this model on six plastic bone and showed that this external guide can give the accurate details that the surgeon is looking for in a revision surgery. Result & discussion. We have performed revision surgery on six bony model utilizing the new external guide that depend on the metaphysical bone mark. In all cases we were able to have a good lock for the external guide enabling us to precisely indicate the flexion extension joint line as well as the femoral rotation accurately. The guide established to us were the trial component should be seated and the surgery after that was quite easy filling the gap with necessary block and augment based on the accurate joint line. Furthermore, performing the surgery this way enabled us to offreem in order to correct the deformity that may result from the fixed angle of the stem in both femoral and tibial component. Our suggested way of performing the revision surgery is to use the metaphysical guide to indicate the entry point for reaming. this will allow the surgeon to offream after which the external guide also block the phantom or trial component indicating both flexion and extension joint line and rotation. After that the surgeon build up to the joint line. Conclusion. Depending on a new landmark outside metaphysical and suggesting a new type of guide will make psi possible regardless of the amount of bony destruction in the epiphyseal area. Furthermore performing the surgery this way will decrease the error that is based on the judgment of the surgeon for his joint line and rotation and point of entry. We believe that further work and development is needed to make it durable for commercial

Introduction. PSI technology have proved helpful in difficult primary Total Knee Replacement. However applying it to revision was impossible due to multiple factor. To Start with the landmark We usually destroy it. There is an extensive damage at the bone at the epiphysis, the implant prevent an accurate visualization and debridement usually change the surface of the bone as well which make applying the psi dyed impossible, we are proposing a new way of using psi in revision where we don't depend on the all masses adjusted in primary. However we depend on the metaphysical area of the bone. Material & method. We have reviewed 56 MRI &CT scans for cases posted for revision and showed clearly that in spite of the extensive bony destruction and metal presence the MRI / CT scan we were able to visualize well the metaphysical area in the intramedullary canal in both tibial and femoral · we have established a special external guide that depends on the outside surface of the metaphysis of the femur. We have tried this model on six plastic bone and showed that this external guide can give the accurate details that the surgeon is looking for in a revision surgery. Result & discussion. We have performed revision surgery on six bony model utilizing the new external guide that depend on the metaphysical bone mark. In all cases we were able to have a good lock for the external guide enabling us to precisely indicate the flexion extension joint line as well as the femoral rotation accurately. The guide established to us were the trial component should be seated and the surgery after that was quite easy filling the gap with necessary block and augment based on the accurate joint line. Furthermore, performing the surgery this way enabled us to offreem in order to correct the deformity that may result from the fixed angle of the stem in both femoral and tibial component. Our suggested way of performing the revision surgery is to use the metaphysical guide to indicate the entry point for reaming · this will allow the surgeon to offream after which the external guide also block the phantom or trial component indicating both flexion and extension joint line and rotation. After that the surgeon build up to the joint line. Conclusion. Depending on a new landmark outside metaphysical and suggesting a new type of guide will make psi possible regardless of the amount of bony destruction in the epiphyseal area. Furthermore performing the surgery this way will decrease the error that is based on the judgment of the surgeon for his joint line and rotation and point of entry. We believe that further work and development is needed to make it durable for commercial

The aim of this paper is to describe the technique and evaluate the effectiveness of the RIA system in the first cases of bone loss treated by the authors with this technique. Between January 2010 and January 2011, ten patients were treated with an average age of fourty six years, with infected bone loss as a result of open fractures in various bone segments, with multiple failed treatment attempts, including three humeri, four femurs and three tibiae. The average size of the initial bone loss was 4 cm, varying from 1 to 8 cm. In 4 patients it was used simultaneously a Ilizarov apparatus with acute compression of the focus, in two patients a Ender pin and monolateral external fixator, three other cases with a SAFE nail with core with antibiotics and in one case an osteosynthesis with a plate and screws. The RIA was introduced with a percutaneous technique with a one pass drilling. The graft thus collected was mixed with appropriate antibiotics and aplied at the defect. The volume of the harvested graft, complications of the donor and recipient and the final results was recorded. The review showed that the average volume of graft was 60 cc, from 20 to 90 cc. In two female patients older than 70 years with osteoporosis, insufficient bone of poor quality was obtained. Problems included a case of iatrogenic fracture of the donor site, due to poor surgical technique and a case of relapse of the nonunion. Regarding the effectiveness of grafts extracted with the RIA system, 90% of the cases achieved consolidation in average of 5 months after grafting, range 3–9 months. This short experience with the RIA system showed that it is an attractive method allowing a rapid removal of a large volume of bone graft with a minimally invasive approach and a short learning curve. It is not indicated in elderly patients with osteoporosis and those with a narrow medullar canal less than 11 mm. Special attention must be done to the need to choose a drill no larger than 1 mm of the diameter of the isthmus, to do a single entry point and with only one drill passage to prevent the weakening of the donor site

Alignment of total joint replacement in the valgus knee can be done readily with intramedullary alignment and hand-held instruments. Intramedullary alignment instruments usually are used for the femoral resection. The distal femoral surfaces are resected at a valgus angle of 5 degrees. A medialised entry point is advised because the distal femur curves toward valgus in the valgus knee, and the distal surface of the medial femoral condyle is used as reference for distal femoral resection. In the valgus knee, the anteroposterior axis is especially important as a reliable landmark for rotational alignment of the femoral surface cuts because the posterior femoral condyles are in valgus malalignment, and are unreliable for alignment. Rotational alignment of the distal femoral cutting guide is adjusted to resect the anterior and posterior surfaces perpendicular to the anteroposterior axis of the femur. In the valgus knee this almost always results in much greater resection from the medial than from the lateral condyle. Intramedullary alignment instruments are used to resect the proximal tibial surface perpendicular to its long axis. Like the femoral resection, resection of the proximal tibial surface is based on the height of the intact medial bone surface. After correction of the deformity, ligament adjustment is almost always necessary in the valgus knee. Stability is assessed first in flexion by holding the knee at 90 degrees and maximally internally rotating the extremity to stress the medial side of the knee, then maximally externally rotating the extremity to evaluate the lateral side of the knee. Medial opening greater than 4mm, and lateral opening greater than 5mm, is considered abnormally lax, and a very tight lateral side that does not open at all with varus stress is considered to be abnormally tight. Stability is assessed in full extension by applying varus and valgus stress to the knees. Medial opening greater than 2mm is considered to be abnormally lax, and a very tight lateral side that does not open at all with varus stress is considered to be too tight. Release of tight structures should be done in a conservative manner. In some cases, direct release from bone attachment is best (popliteus tendon); in others, release with pie-crusting technique is safe and effective. In knees that are too tight laterally in flexion, but not in extension, the LCL is released in continuity with the periosteum and synovial attachments to the bone. When this lateral tightness is associated with internal rotational contracture, the popliteus tendon attachment to the femur is also released. The iliotibial band and lateral posterior capsule should not be released in this situation because they provide lateral stability only in extension. The only structures that provide passive stability in flexion are the LCL and the popliteus tendon complex, so knees that are tight laterally in flexion and extension have popliteus tendon or LCL release (or both). Stability is tested after adjusting tibial thickness to restore ligament tightness on the lateral side of the knee. Additional releases are done only as necessary to achieve ligament balance. Any remaining lateral ligament tightness usually occurs in the extended position only, and is addressed by releasing the iliotibial band first, then the lateral posterior capsule, if needed. The iliotibial band is approached subcutaneously and released extrasynovially, leaving its proximal and distal ends attached to the synovial membrane. In knees initially too tight laterally in extension, but not in flexion, the LCL and popliteus tendon are left intact, and the iliotibial band is released. If this does not loosen the knee enough laterally, the lateral posterior capsule is released. The LCL and popliteus tendon rarely, if ever, are released in this type of knee. Finally, the tibial component thickness is adjusted to achieve proper balance between the medial and lateral sides of the knee. Anteroposterior stability and femoral rollback are assessed, and posterior cruciate substitution is done, if necessary, to achieve acceptable posterior stability

Classical AO teaching recommends that a syndesmosis screw should be inserted at 25 to 30 degree angle to the coronal plane of the ankle. In practice accurately judging the 25/30 degree angle can be difficult, and there are several reports based on post operative CT scans demonstrating that a significant minority of patients have poorly operatively reduced syndesmotic injuries. The CT scans of 200 normal ankles in one hundred individuals which had been performed as part a CT angiogram were retrospectively examined. The centroid of the fibula and tibia in the axial plane 15mm proximal to the talar dome was calculated. Since a force vector between the centroid of the fibula and the tibia in the axial plane should not displace the fibula relative to the tibia, a line connecting the two centroids was therefore postulated to be the ideal syndesmosis line, and also the optimum position in which to place a compression clamp after reducing the syndesmosis. Where this ideal line passed through the lateral border of the fibula, and through the medial malleolus was then noted. The ideal syndesmosis line was shown to pass through the fibula with in 2mm of the lateral cortical apex of the fibula, and the anterior half of the medial malleolus in 100% of the ankles studied. The results support the concept that in the operatively reduced syndesmosis, the anterior half of the medial malleolus can be used as a reliable guide for aiming the syndesmosis drill hole, provided that the fibular entry point is at or adjacent the lateral fibular apex. The corollary of these findings is that a screw inserted through a plate on the standard antero-lateral border of the fibula, or a plate in the anti-glide position posteriorly, cannot lie in the centroidal axis of the ankle

While image guidance and neuro-navigation have enabled a more accurate positioning of pedicle implants, robot-assisted placement of pedicle screws appears to overcome the disadvantages of the two first systems. However, recent data concerning the superiority of robots currently available to assist spinal surgeons in the accurate positioning of implants are conflicting. The aim of our study was to evaluate the percentage of accurate positioning of pedicle screws inserted using a new robotic-guidance system. Patients were operated on successively by the same surgeon using robotic-assistance (RA; n=40) or by the freehand conventional technique (FH; n=54). Ten and eleven patients from the robot (RG) and freehand (FHG) groups respectively, age-matched and all suffering from degenerative lumbar spine disease were compared. Patient characteristics as well as the duration of the operation and of exposure to X-rays were recorded. The Gertzbein Robbins classification was used to evaluate implant placement. Data wer compared between the groups. Pedicle screw placement in RG patients was achieved using the ROSA™ (Medtech) robot comprising a compact robotic arm on a floor-fixable mobile base. By permanently monitoring the patient's movements, this image-guided tool helps more accurately to pinpoint the pedicle entry point and to control the trajectory. The mean age of patients in each group (RG and FHG) was 63 years. Mean BMI and operating time among the RG and FHG were respectively 26 and 27 kg/m. 2. , and 187 and 119 min. Accurate placement of the implant (score A-B) was achieved in 97.2% of patients in the RG (n=36) and in 92.6% of those in the FHG (n=54). Four implants in the RG were placed manually following failed robotic assistance. The mean duration of X-ray exposure per patient was 1 min 42s in the RG and 41s in the FHG. We report a higher rate of accuracy with robotic assistance as compared to the FH technique. Exposure time was greater in the RG partly due to the fluoroscopic control of the implants required for this pilot study of feasibility. Limitations of the study include its small sized and non-randomised sample. Nevertheless, these preliminary results are encouraging for the development of new robotic techniques for spinal surgery

Purpose of the study. Percutanous acetabular surgery is a new and developing technique in fixation of acetabulum fractures. The most common screw used is the anterior column screw that traverses anterograde or retrograde through the anterior column of the acetabulum. Standard height and width calculations derived from CT scans do not take the trajectory of the screw into consideration. They have been shown to exaggerate the available safe bone corridor for screw passage. Posterior column screws can be placed in a retrograde fashion via the ischial tuberosity to fixate posterior column. Limited international data is available and no studies to date have been conducted on the South African population. This study assesses the anterior and posterior acetabular columns of South African individuals and ascertains the safe bone corridor sizes. Methods. Pelvic CT-scans of 100 randomly selected patients were reviewed. Specific computer software was used to virtually place anterior screws through the anterior acetabular column, in its clinical trajectory. Specific entry points inferior to the pubic tubercles significantly changed the relation of the screw trajectory to the mid- column isthmus and were incorporated in the measurement of the anterior column. All the available lengths and diameters were measured and averages were calculated for males and females. Results. On average, males have longer and larger diameter anterior columns. The entry point on the pubic tubercle has a significant impact on the relative diameter at the mid- column. Not all commercially available cannulated screw diameters are safe to place into the anterior column. Conclusion. Although the international literature shows that percutaneous anterior column fixation is of value for early mobilisation after fractures, intimate knowledge of the local data regarding the available safe corridors for screw passage is limited. This study shows the safe bone corridors that can be used to avoid breaching the cortex during screw insertion. It also recommends safe screw diameters. NO DISCLOSURES

Aim. Treatment for distal third shaft fractures of humerus is very challenging especially if its comminuted and bone is osteopenic. They are commonly treated with plating. Plating has complications of iatrogenic radial nerve palsy. We report our case series of distal third fractures of humerus treated with retrograde Halder Humeral Nail. Materials and methods. Since 1994 to 2010 we have 576 fractures of humerus treated with retrograde Halder Humeral nail. Of these 45 were distal third extra articular fractures of humerus. Average age of patients at the time of surgery was 30.4 years (Range 15–82 years, Median 33 years). Of 45 patients 26 were females and 19 males.3 out of 45 had non union at the time of presentation. The nail was locked distally with one or two screws and proximally with a screw and tripwire. The entry point of the nail was roof of olecranon fossa (contrary to standard retrograde nails where it is an inch above olecranon fossa) This design of nail allows it be used for even very distal fractures. All patients were followed till clinical and radiological signs of union. 1 patient was lost to follow up. Results. Average time to fracture healing was 13.9 weeks (Range 9–36 weeks). There were 2 cases of non union, one healed at 9 months with 2. nd. surgery. The other non union was asymptomatic and did not agree for further surgery. There was one reported case of infection.7 patients had nail removal electively on request. All the patients achieved full range of elbow and shoulder movement. No reported cases of iatrogenic radial nerve palsy. Conclusion. Our results of distal third fractures of humerus treated with retrograde Halder Humeral Nail are excellent. It avoids big exposure as needed in plating and complication of iatrogenic radial nerve palsy

Background. The new Fassier-Duval Telescopic IM System (FD-rod) has the advantage of a single entry point over the traditional telescopic rods such as the Bailey-Dubow or Sheffield rods. Although encouraging early results were presented by François Fassier, there is no formal publication in the literature as yet. Methods. The first 24 consecutive cases (age 1.5-12.5 years) with a minimum of 1 year follow-up (1-2.4 years) after femoral and/or tibial FD-rods were reviewed to assess complications involving migration, non-telescoping, joint intrusion, infections and re-operation rates in patients with Osteogenesis imperfecta (OI, 15 cases), congenital tibial pseudarthrosis (CPT) in Neurofibromatosis Type1 (NF1, 2 cases), and Epidermal Naevus syndrome (1 case). In 6 cases of patients with Hypophosphataemic Rickets FD-rods were combined with an Ilizarov frame. Results. The OI patient group had a 13% re-operation rate (2/15) for proximal rod migration and a 40% complication rate (6/15 cases): rod migration and limited telescoping (5), intra-operative joint intrusion (1). There were no infections. All NF1 CPT (2) and Epidermal Naevus syndrome (1) cases required several re-operations for non-union, loss of fixation, shortening (negative telescoping), migration and/or joint intrusion – mainly due to the severe underlying pathology with insufficient longitudinal or torsional stability and diminished healing capacity. The 6 cases with Hypophosphataemic Rickets, combined with Ilizarov frame fixation, had a 50% complication rate (3/6) and a 17% re-operation rate (1/6): 2 cases did not telescope and 1 case of peroneal neuropraxia required neurolysis. Conclusion. In our experience the technique of using Fassier-Duval rods is demanding and associated with some intra- and post-operative pitfalls. We are happy to continue its use in OI patients when there is longitudinal stability and sufficient bone healing. However, in circumstances of insufficient stability and bone healing potential, further stabilisation e.g. with an Ilizarov frame may be beneficial

Successful ORIF of proximal humeral fractures requires a careful assessment of the patient factors (age/osteoporosis/functional expectations), accurate identification the fracture segments (head/shaft/tuberosities) and accessory factors which are of vascular and surgical relevance (length of posteromedial metaphyseal head extension, integrity of medial soft tissue hinge, head split segments, tuberosity/head segments impacted to-gether or distracted apart). Fixation of the fracture can be achieved by a number of techniques because of the multiple factors that often apply—numerous techniques are usually required of the surgeon. The principles of fixation require accurate restoration of the head and tuberosity orientation, fixation of the metaphyseal segments (tuberosities) results in a stable circular platform on which the head segment rests. Thus, the fixation of choice acts as a load sharing device not a load bearing device. This fixation is often augmented with tension band and circlage suture fixation. These concepts are especially applicable to the osteoporotic patient. The order of fixation requires that the medial hinge not be disrupted. If it is disrupted in the younger patient it requires fixation first. All tuberosity segments are tagged with ethibond sutures. The head and the largest tuberosity segment are reduced and held with k-wire or canulated scews, avoiding the central medullary canal entry point. If the head tuberosity segment is unstable in relation to the shaft, the fixation implant of choice (plate/intramedullary) is chosen and the head/tuberosity complex is reduced to the shaft. Depending on the fracture segments and the degree of comminution this may require compression of distraction. Post-op the patient is immobilised in external rotation to balance the cuff forces. If very rigid fixation is achieved then early mobilisation is undertaken to minimise the adhesions due to opening of the subdeltoid space. If fixation is tenuous movement is commenced a 3–4 weeks. AVN of the humeral head with good tuberosity head architecure can be salvaged. The diagnosis of AVN is determned at three months with a MRI and consideration given to Zolidronate therapy. Post-traumatic stiffness with good architecture can be salvaged with an arthroscopic capsular release

The use of cervical pedicle screws as anchors in posterior reconstruction surgery has not been widely accepted due to the neurological or vascular injury. We thus sought to investigate the accuracy of free-handed pedicle screw placement in the cervical and upper thoracic spine at the early stage of clinical application. Eight patients (five males and three females) were included in this study. Mean age was 63 years (31 to 78 years). There were three patients with rheumatoid arthritis, three with cervical fracture-dislocation, and two with spinal metastasis. Twenty-four pedicle screws (3.5 mm diameter: Vertex, Medtronic Sofamordanek) were placed into the pedicle from C2 to T2 level by free-handed technique2). Grade of breaching of pedicle cortex was divided into four groups (Grade 0–3). In addition, screw axis angle (SAA) were calculated from the horizontal and sagittal CT images and compared with pedicle transverse angle (PTA). Furthermore, perioperative complications were also examined. Our free-handed pedicle screw placement with carving technique is as follows: A longitudinal gutter was created at the lamina-lateral mass junction and then transverse gutter perpendicular to the longitudinal gutter was made at the lateral notch of lateral mass. The entry point of the pedicle screw was on the midline of lateral mass. Medial pedicle cortex through the ventral lamina was identified using the probes to create the hole within the pedicle. The hole was tapped and the screw was gently introduced into the pedicle to ensure the sagittal trajectory using fluoroscopy. In the transverse direction, 22 out of 24 screws (92%) were entirely contained within the pedicle (Grade 0). In contrast, only teo screws (8%) produced breaches less than half the screw diameter (Grade 1). In the sagittal direction, all screws were within the pedicle (Grade 0). Screw trajectories were not consistent with anatomical pedicle axis angle; the mean SAA were smaller than the mean PTA at all levels. The pedicle diameter ranged from 3.9 to 9.2 mm. The mean value gradually increased toward the caudal level. There were no neurological and vascular complications related to screw placement

Introduction. Hip resurfacing is a bone sparing approach to treating arthritis in younger or more active patients. Accurate positioning of the femoral component in the hip resurfacing procedure is essential for the success of the operation [1-2]. An alignment guide assisting the operator in accurately positioning the resurfacing implant may increases the success rate of the operation. This study focuses on the effectiveness of a CT based resurfacing alignment guide, shown in Figure 1. Materials and Methods. Four full fresh frozen human cadaveric specimens were CT scanned to reconstruct bone models of the femoral head/neck geometries with no cartilage included in the segmentation. Femoral head resurfacing alignment guides were then created through computer aided design (CAD) modeling using landmarks from the reconstructed bone models for proper seating. A total of 12 resurfacing alignment guides (3 for each specimen) were prepared. After the exposure of the hip joints, the first two out of three resurfacing alignment guides were used to asses the fit, stability, and visual assessment of valgus and version alignments. The third resurfacing alignment guide for each specimen was placed on the femoral head/neck region and the guide wire was drilled into the femur. A fluoroscopy image was taken to assess and measure the valgus and version alignment. The acceptance criteria for valgus alignment, as shown in Figure 2, is set to be ±2.5° from a line parallel to the medial calcar of the femoral neck, Similarly, the acceptance criteria for the version alignment was set to be ±2.5° from a line passing through the neutral axis of the femoral neck. Results and Discussion. The resurfacing alignment guides were firmly secured on the femoral head; they were stable and their auxiliary guide wire placement features were allowed for visual assessments of the alignment. The planned and the measured valgus angles were in agreement and the version alignment neutral to femoral neck axis was within the acceptable range. Current manual alignment guides require user experience for locating the entry point and trajectory for femoral head resurfacing. The CT based patient matched alignment guide offers a precise and reliable implant positioning, reducing the possibility of notching of the femoral neck and leaving any air pocket around the distal periphery of the implant which could lead to neck fracture or implant loosening, respectively. This study demonstrates the effectiveness of a guide made based on the patient specific CT scan assisting the operator in the precise alignment of the femoral implant. The potential benefits of this technology are consistent and accurate alignment of the implant, reduced OR time and ease of use with reduced instrumentation