Osteotomies in the musculoskeletal system are joint preserving procedures to correct the alignment of the patient. In the lower limb, most of the pre-operative planning is performed on full leg weightbearing radiographs. However, these images contain a 2-dimensional projection of a 3-dimensional deformity, lack a clear visualization of the joint surface and are prone to rotational errors during patient positioning. Weightbearing CT imaging has demonstrated to overcome these shortcomings during the first applications of this device at level of the foot and ankle. Recent advances allow to scan the entire lower limb and novel applications at the level of the knee and hip are on the rise. Here, we will demonstrated the current techniques and 3-dimensional measurements used in supra- and inframalleolar osteotomies around the ankle. Several of these techniques will be transposed to other parts in the lower limb to spark future studies in this field

High tibial osteotomy (HTO) is an effective surgical treatment for isolated medial compartment knee osteoarthritis; however, widespread adoption is limited due to difficulty in achieving the planned correction, and patient dissatisfaction due to soft tissue irritation. A new HTO system – Tailored Osteotomy Knee Alignment (TOKA®, 3D Metal Printing Ltd, Bath, UK) could potentially address these barriers having a custom titanium plate and titanium surgical guides featuring a unique mechanism for precise osteotomy opening as well as saw cutting and drilling guides. The aim of this study was to assess the accuracy of this novel HTO system using cadaveric specimens; a preclinical testing stage ahead of first-in-human surgery according to the ‘IDEAL-D’ framework for device innovation. Local ethics committee approval was obtained. The novel opening wedge HTO procedure was performed on eight cadaver leg specimens. Whole lower limb CT scans pre- and post-operatively provided geometrical assessment quantifying the discrepancy between pre-planned and post-operative measurements for key variables: the gap opening angle and the patient specific surgical instrumentation positioning and rotation - assessed using the implanted plate. The average discrepancy between the pre-operative plan and the post-operative osteotomy correction angle was: 0.0 ± 0.2°. The R2 value for the regression correlation was 0.95. The average error in implant positioning was −0.4 ± 4.3 mm, −2.6 ± 3.4 mm and 3.1 ± 1.7° vertically, horizontally, and rotationally respectively. This novel HTO surgery has greater accuracy and smaller variability in correction angle achieved compared to that reported for conventional or other patient specific methods with published data available. This system could potentially improve the accuracy and reliability of osteotomy correction angles achieved surgically

Conventional proximal tibial osteotomy is a widely successful joint-preserving treatment for osteoarthritis; however, conventional procedures do not adequately control the posterior tibial slope (PTS). Alterations to PTS can affect knee instability, ligament tensioning, knee kinematics, muscle and joint contact forces as well as range of motion. This study primarily aimed to provide a comprehensive investigation of the variables influencing PTS during high tibial osteotomy using a 3D surgical simulation approach. Secondly, it aimed to provide a simple means of implementing the findings in future 3D pre-operative planning and /or clinically. The influence of two key variables: the gap opening angle and the hinge axis orientation on PTS was investigated using three independent approaches: (1) 3D computational simulation using CAD software to perform virtual osteotomy surgery and simulate the post-operative outcome. (2) Derivation of a closed-form mathematical solution using a generalised vector rotation approach (3) Clinical assessment of synthetically generated x-rays of osteoarthritis patients (n=28; REC reference: 17/HRA/0033, RD&E NHS, UK) for comparison against the theoretical/computational approaches. The results from the computational and analytical assessments agreed precisely. For three different opening angles (6°, 9° and 12°) and 7 different hinge axis orientations (from −30° to 30°), the results obtained were identical. A simple analytical solution for the change in PTS, ΔP. s,. based on the hinge axis angle, α, and the osteotomy opening angle, θ, was derived:. ΔP. s. =sin. -1. (sin α sin θ). The clinical assessment demonstrated that the absolute values of PTS, and changes resulting from various osteotomies, matched the results from the two relative prediction methods. This study has demonstrated that PTS is impacted by the hinge axis angle and the extent of the osteotomy opening angle and provided computational evidence and analytical formula for general use

Introduction. Assessment of the humeral head translation with respect to the glenoid joint, termed humeral head migration (HHM), is crucial in total shoulder arthroplasty pre-operative planning. Its assessment informs current classification systems for shoulder osteoarthritis as well as the evaluation of surgical correction. In current clinical practice, HHM assessment relies on computed-tomography (CT) imaging. However, the associated supine position might undermine its functional relevance as it does not reflect the weight-bearing condition with active muscle engagement associated with the upright standing position of most daily activities. Therefore, we assessed to what extent HHM in a supine position is associated with HHM in a range of functional arm positions. Method. 26 shoulder osteoarthritis patients and 12 healthy volunteers were recruited. 3D shapes of the humerus and scapula were reconstructed from their respective CT scans using an image processing software. 3. , and their CT-scan-based HHMs were measured. Furthermore, all subjects underwent low-dose biplanar radiography . 4. in four quasi-static functional arm positions while standing: relaxed standing, followed by 45 degrees of shoulder extension, flexion, and abduction. Using a previously validated method implemented in the programming platforms. 5. , 3D shapes were registered to the pairs of biplanar images for each arm position and the corresponding functional HHM was measured. Bivariate correlations were assessed between the CT-based HHM and each functional arm position. Result. HHM in 45 degrees of flexion and extension both showed significant and strong correlations (r>0.66 and P<0.01) with HHM assessed in the supine position. However, such a high correlation was not found for relaxed standing and 45 abduction. Conclusion. Although HHM in a supine position correlates with HHM in 45-degree extension and flexion, it is poorly associated with the HHM in abduction and relaxed standing. These results may suggest the inclusion of more functionally-relevant patient positioning toward better-informed shoulder arthroplasty planning. Acknowledgement. Funding from PRosPERos-II Project

The medial opening-wedge high tibial osteotomy (OW-HTO) is an accepted option to treat the isolated medial compartment osteoarthritis (OA) in varus knee. Despite satisfactory outcomes were described in literature, consistent complication rate has been reported and the provided accuracy of coronal alignment correction using conventional HTO techniques falls short. Patient specific instrumentations has been introduced with the aim to reduce complications and to improve the intra-operative accuracy according to the pre-operative plan, which is responsible for the clinical result of the surgery. In this talk, an overview of the clinical results of HTO patient specific instrumentation available in literature will be performed. Moreover, preliminary intra-operative and clinical results of a new customised 3-D printed cutting guide and fixation plate for OW-HTO will be presented

Summary Statement. We present a simple and useful geometrical equation system to carry out the pre-operative planning and intra-operative assessments for total knee arthroplasty. These methods are extremely helpful in severely deformed lower limbs. Introduction. Total knee arthroplasty is a highly successful surgery for most of the patients with knee osteoarthritis. With commercial instruments and jigs, most surgeons can correct the deformity and provided satisfactory results. However, in cases with severe extra-articular deformity, the instruments may mislead surgeons in making judgment of the true mechanical axis. We developed a geometrical equation system for pre-operative planning and intra-operative measurement to perform correct bony cuts and achieve good post-operative axis. Patients & Methods. From 2008 to 2012, twenty-four patients with severe extra-articular deformities of low limbs underwent total knee arthroplasties for osteoarthritis. The deformities included malunion of femoral or tibial shafts with angulation, non-union of femoral supracondylar fractures, failed high tibia osteotomies, severe bowing of femurs, and other post-traumatic sequelae. The intra-medullary or extra-medullary guide devices were not possible to provide correct axis in these cases. For pre-operative planning, we analyzed the deformities on triple-film scanography and standing anterior-posterior and lateral X-ray films. The angles needed to be corrected in coronal and sagittal planes were measured. A geometrical equation system was applied to calculate the thickness of the proximal tibia cut and distal femoral cut. If the flexion contracture was presented, the degree of necessary elevation of joint line was also calculated. Intra-operatively, the degree of rotation of anterior and posterior femoral cuts was assessed after proximal tibial and distal femoral cuts. The sizes of prosthesis were judged according to the balance between flexion and extension gaps. A 3-in-1 jig was used for chamfering of the femur. After fine-tuning of bony cuts and balancing of soft tissue, the prostheses were cemented. The conventional intra-medullary and extra-medullary guiding devices were not used during the whole procedure. Results. All of the patients achieved satisfactory results in the aspect of pain relief and functional outcomes. All patients had good post-operative axis in coronal plane (varus or valgus deformity < 3 degrees). Twenty-two patients (92%) achieved good sagittal alignments (deformity < 3 degrees). The results were compatible with those in the patient population without those severe deformities. There was no major complication among these patients. Discussion/Conclusion. In this series, we present a simple and useful geometrical equation system to carry out the pre-operative planning and intra-operative assessments for total knee arthroplasty. These methods are extremely helpful in severely deformed lower limbs. Optimal post-operative alignments were achieved in this series and no major complication was found

Introduction and Objective. The aim of this study was to evaluate whether CT-based pre-operative planning, integrated with intra-operative navigation could improve glenoid baseplate fixation and positioning by increasing screw length, reducing number of screws required to obtain fixation and increasing the use of augmented baseplate to gain the desired positioning. Reverse total shoulder arthroplasty (RSA) successfully restores shoulder function in different conditions. Glenoid baseplate fixation and positioning seem to be the most important factors influencing RSA survival. When scapular anatomy is distorted (primitive or secondary), optimal baseplate positioning and secure screw purchase can be challenging. Materials and Methods. Twenty patients who underwent navigated RSA (oct 2018 and feb 2019) were compared retrospectively with twenty patients operated on with a conventional technique. All the procedures were performed by the same surgeon, using the same implant in cases of eccentric osteoarthritis or complete cuff tear. Exclusion criteria were: other diagnosis as proximal humeral fractures, post-traumatic OA previously treated operatively with hardware retention, revision shoulder arthroplasty. Results. The NAV procedure required mean 11 (range 7–16) minutes more to performed than the conventional procedure. Mean screw length was significantly longer in the navigation group (35.5+4.4 mm vs 29.9+3.6 mm; p . .001). Significant higher rate of optimal fixation using 2 screws only (17 vs 3 cases, p . .019) and higher rate of augmented baseplate usage (13 vs 4 cases, p . .009) was also present in the navigation group. Signficant difference there is all in function outcomes, DASH score is 15.7 vs 29.4 and constant scale 78.1 vs 69.8. Conclusions. The glenoid component positioning in RSA is crucial to prevent failure, loosening and biomechanical mismatch, coverage by the baseplate of the glenoid surface, version, inclination and offset are all essential for implant survival. This study showed how useful 3D CT-based planning helps in identifying the best position of the metaglena and the usefulness of receiving directly in the operation theater real-time feedback on the change in position. This study shows promising results, suggesting that improved baseplate and screw positioning and fixation is possible when computer-assisted implantation is used in RSA comparing to a conventional procedure

Neck of femur fractures are a common presentation and certain patients can be managed with a total hip replacement. To receive a total hip replacement the pelvic X-rays should be templated as per AO guidelines and a common way this is performed is by including a calibration marker on the X-ray. The aim of this study is to assess and improve upon the use of the calibration marker. Details of patients admitted with a neck of femur fracture from January 1st 2018 until December 31st 2018 were gathered and used to review each initial X-ray and determine if a calibration marker was included. 376 patients were admitted with a neck of femur fracture over the one year period. 36% of patients did not have a calibration marker on their initial pelvic X-ray and 11% did not have a chest X ray. 215 patients had an intracapsular fracture and 39 went on to have a total hip replacement. 12 patients were lacking a calibration marker on their original X ray and required a repeat X ray. After a poster was placed in the radiographer booth acting as a visual aid, the use of a calibration marker improved from 62% to 70%. Calibration markers are useful tools which can aid the pre-operative planning for hip replacement surgeries shortening operative time, increase precision and reduce prosthetic loosening, lowers the risk of peri-prosthetic fractures, reduce leg length discrepancy and ensure the required implants are available. If a marker is not included on the initial X-rays, and a patient has a neck of femur fracture which requires a joint replacement, they may have to have additional X-rays performed as was the case for 12 patients in this study. This process leads to possible delays in surgery, additional radiation and increased healthcare costs

Revision anterior cruciate ligament (ACL) reconstruction is a technically demanding procedure, reporting poorer outcomes compared to the primary procedure. Identification of the cause of primary failure and a thorough pre-operative evaluation is required to plan the most appropriate surgical approach. 3D printing technology has become increasingly commonplace in the surgical setting. In particular, patient-specific anatomical models can be used to aid pre-operative planning of complicated procedures. We have conducted a qualitative study to gauge the interest amongst orthopaedic knee surgeons in using a 3D-printed model to plan revision ACL reconstructions. A tibia and femur model was printed from one patient who is a candidate for the procedure. The binder jetting printing technique was performed, using Visijet PXL Core powder. 12 orthopaedic knee surgeons assessed the usefulness of the 3D-printed model compared to conventional CT images on a likert scale. 6 key steps of preoperative planning were assessed, including the size and location of the tunnel defects, the need for notchplasty, and whether a staged revision was required. We found that surgeons preferred the 3D-printed model to conventional CT images only, and 83% of them would use such a model for both pre-operative simulation, and as an intra-operative reference. However, there were some variation in the perceived usefulness of the model in several areas assessed. This may reflect differences in individual approach towards planning of the procedure. Our findings suggest that 3D-printed models could be a versatile pre-operative and intra-operative tool for complicated arthroscopic knee surgery. While 3D printing technology is becoming increasingly accessible and affordable, in-depth cost-effectiveness studies need to be conducted before it can be integrated into clinical. Further study would be needed to determine the clinical utility and economic cost-effectiveness of the 3D-printed model in revision ACL reconstruction

Reconstruction of severe acetabular defects during revision hip arthroplasty presents a significant surgical challenge. Such defects are associated with significant loss of host bone stock, which must be addressed in order to achieve stable implant fixation. A number of imaging techniques including CT scanning with 3D image reconstruction are available to assist the surgeon in the pre-operative planning of such procedures. We describe the use of a novel technique to assist the pre-operative planning of severe acetabular defects during revision hip arthroplasty. Patient and Methods – We present the use of this technique in the case of a 78 year old patient who presented 20 years from index procedure with severe hip pain and inability to weight bear due aseptic loosening of a previously revised total hip arthroplasty. A Paprosky 3B defect was noted with intra-pelvic migration of the acetabular component. Pre-operative investigations included: inflammatory markers, pelvic CT scan with 3D reconstruction, pelvic angiography and hip aspiration. Using DICOM images obtained from the CT scan, we used free open source software to carry out a 3D surface render of the bony pelvis. This was processed and converted to a suitable format for 3D printing. Using selective laser sintering, a physical 3D model of the pelvis, acetabular component and proximal femur were produced. Using this model the surgeon was able to gain an accurate representation of both the position of the intra-pelvic cup and more accurately assess the loss of bone stock. This novel technique is particularly useful in the pre-operative planning of such complex acetabular defects in order to determine if/which reconstruction technique is most likely to be successful. 3D printing is a relatively recent technology, which has numerous potential clinical applications. This is the first reported case of this technology being used to assess acetabular defects during revision hip arthroplasty. The use of this technology gives the surgeon a 3D model of the pelvis, quickly (7 days from CT) and at a tenth of the cost (£280) of producing such a model through the traditional commercial routes. The model allowed the surgeon to size potential implant, quantify the amount of bone graft required (if applicable) and to more accurately classify the loss of acetabular bone stock

Introduction. Simultaneous correction of knee varus malalignment with medial open wedge high tibial osteotomy (MOWHTO) combined with anterior cruciate ligament (ACL) surgery aims to address symptomatic unicompartmental osteoarthritis in addition to restore knee stability in order to improve outcomes. The aim of this study is to present at least 5 years results of 32 patients who underwent simultaneous knee realignment osteotomy with ACL surgery. Methods. Patients with symptomatic instability due to chronic ACL deficiency or failed previous ACL surgery together with a varus malalignment of ≥6°, previous medial meniscectomy and symptomatic medial compartment pain who were treated with MOWHTO combined with ACL surgery were enrolled. ACL surgery was performed with the anatomical single bundle all-inside technique using TightRope. ®. RT (Arthrex, Naples, FL, USA) and MOWHTO using TomoFix. ®. medial high tibia plate (DePuy Synthes, Raynham, MA, USA) in all cases. Patients were evaluated preoperatively and at 6 months, 12 months and annually postoperatively using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS) and Euroqol's Visual Analogue Score (VAS) for pain. Results. 32 patients (22 men and 10 women) with a mean age of 41.2 years and mean BMI of 28.6 kg/m. 2. , underwent the combined procedures. Tibiofemoral neutral re-alignment was achieved in all patients with HTO. Complete subjective and objective scores have been obtained in 84.4% of patients with at least 5 years of follow-up (mean 8.7 years). An improvement in total KOOS of 27.1 points (p<0.003), OKS of 15.1 (p<0.003) and VAS for pain of 24.7 points (p<0.001) were detected. No ACL reconstruction failure was noted. Complications consisted of one superficial wound infection and one delayed union. Plate removal was needed in 20 (62.5%) patients due to pes anserinus pain. Conclusions. Simultaneous restoration of coronal knee axis by applying HTO and stability by ACL reconstruction/revision were reported to offer excellent improvement in early outcomes in patients with ACL rupture and symptomatic unicompartmental osteoarthritis. The combined procedure requires careful pre-operative planning and is therefore technically challenging. However, by restoring the neutral axis and providing stability, it represents a good joint preserving alternative to arthroplasty for active middle-aged patients

Over 70,000 hip fractures occur annually in the UK. Both SIGN (111) and NICE (124) give guidance on optimal management of these patients. Both suggest cemented hemiarthroplasty should be used in those without contra-indications, as cemented implants are associated with less thigh pain, subsidence and a better functional outcome. Cardiorespiratory compromise secondary to bone cement implantation syndrome (BCIS) is however a concern in those with pre-existing cardiorespiratory disease (NYHA grade 3–4, pulmonary hypertension) or pathological fracture [3]. The aim of our study was to audit the practice of a University of Glasgow hospital with regard to cemented hemiarthroplasty. We retrospectively reviewed data on all patients treated with hemiarthroplasty for hip fracture at the Southern General Hospital between 01/01/12-02/04/12. Patient demographics, pre-operative plan, procedure performed, ASA grade and pre-morbid mobility were recorded. Results. Twenty-three hemiarthroplasties were performed. The median age was 82 (70–101). No patient aged over 90 underwent cemented hemiarthroplasty. Cemented implants (JRI, Furlong) were used in 26% (n=6) while 74% (n=17) underwent uncemented (Stryker, Austin-Moore) hemiarthroplasty. ASA grade was recorded in eight (35%). There were four ASA-2 patients (mild systemic disease not limiting activity) of which 75% underwent uncemented hemiarthroplasty. Pre-morbid mobility was recorded in eight (35%). All three independently mobile patients underwent uncemented hemiarthroplasty. Six (26%) had a documented pre-operative plan with regards to cement use. This study highlights the disparity between current recommendations and our Centres’ practice. Most notable were: poor recording of pre-operative mobility, poor documentation of a pre-operative surgical plan, the low use of cemented fixation even in fit mobile patients and the lack of ASA grade recording (stratification of risk) by our anaesthetic colleagues. We suggest a documented pre-operative discussion between the surgeon and anaesthetist to establish BCIS risk and decide on use of cemented arthroplasty taking into account age and mobility

Summary Statement. Our data suggest that postoperative component positioning in TKA with PSPG is not consistent with pre-operative software planning. More studies are needed to rule out possible learning curve in this study. Introduction. Patient specific positioning guides (PSPGs) in TKA are based on MRI or CT data. Preoperatively, knee component positions can be visualised in 3-dimensional reconstructed images. Software allows anticipation of component position. From software planning PSPGs are manufactured and those PSPGs represent intra-operative component alignment. To our knowledge, there are no studies comparing pre-operative software planning with post-operative alignment. Aim of this study is to investigate the correlation between pre-operative planning of component positioning and the post-operative achieved alignment with PSPG technique. Patients & Methods. The first 25 TKA (cemented Vanguard® Complete Knee System, Biomet) with PSPG (Signature™ Biomet) performed at Telemark Hospital in 2009–2010 and the first 17 TKA with PSPG performed at Oslo University Hospital in 2010–2011 were included. A postoperative CT scanning and measurement protocol was used (Perth protocol). CT measurements were performed by 2 independent observers and comparative with pre-operative software (Materialise) planning. Component position angles of femur and tibia were measured. Mechanical axis for both femoral and tibial component angles in all planes was defined as zero degrees. Target angle for femoral component in sagittal plane was set to 2,8 degrees flexion on average and for the tibial tray to 3 degrees of posterior slope. Tibial rotation was in most cases obtained by using extra-medullary guide and therefore not included in this study. Results. In respectively coronal, sagittal and axial plane the femoral component angle was on average 1.2° in varus, SD 1.6 (1.7° valgus −4.5° varus), 4.4° in flexion, SD 3.9 (17.3° flexion −1.6° extension) and 0.5° in external rotation, SD 0.1 (2.3° internal rotation −4.3° external rotation). For the tibial component angle the component was on average 0,5° in varus (3.5° valgus −7.3° varus) and 3.7° posterior slope, SD 2.3 (8.8° flexion −2.4° extension). Intra-class correlation (ICC) between the 2 independent observers was for femoral component in coronal, sagittal and axial plane 0.85, 0.93 and 0.63 and tibial component in coronal and sigittal plane 0.94 and 0.95. Discussion/Conclusion. We expected that our measurements would be close to the pre-operative values. Although the mean values of post-operative measurements are close to pre-operative software planning, we found a considerable spread. Possible explanation might be error levels in pre-operative wrong identification of landmarks from MRI and/or different identification of bony landmarks on CT and intra-operative errors. All measurements were performed from the first Signatures performed in both hospitals. An early learning curve might explain some of the outliers. Time between manufacturing date and performed operation was in most cases several months, but less than the advocated 6 months. This time gap can theoretically provide a less proper fit in some cases due to slight change of anatomy in a progressive osteoarthritis. Our data suggest that postoperative positioning is not consistent with preoperative planning. This may be caused by the an early learning curve. It is uncertain whether this inconsistency is of clinical relevance. More data is necessary to prove any benefit of PSPG compared to existing procedures for TKA

An adult acquired flatfoot deformity (AAFD) is a complex 3D deformity. Surgical correction consists of a medial calcaneal osteotomy (MCO) but shows limitations due to the current 2D assessment. Therefore, the aim is to determine the influence of an MCO on the longitudinal foot arch assessed by 2D and 3D weightbearing CT (WBCT). Seventeen patients with a mean age of 44,5 years (range 18–66 yrs) were retrospectively included. MCO was indicated in a stage II AAFD (N=15) and a post-traumatic valgus deformity (N=2). Pre- and post-operative imaging was obtained from a WBCT. The height of the longitudinal foot arch was measured as the distance from the navicular tuberositas to the floor (Navicular Height, NH) on 2D CT images (NH. 2D. ) and computed on 3D CT data (NH. 3D. ). Additionally, 3D assessment could compute the degree of exorotation (α) of the navicular bone towards the vertical axis. The mean pre-operative NH. 2D. and NH. 3D. were respectively 29.57mm ± 7.59 and 28.34mm ± 6.51. These showed to be statistically different from the mean post-operative NH. 2D. and NH. 3D. , respectively 31.62mm ± 6.69 and 31.67mm ± 6.47 (p < 0,001). A statistical difference was also found when comparing the mean degree of exorotation in pre- and post-operative, respectively: α. pre. =14.08° ± 4,92 and the α. post. =19,88° ± 3.50 (p < 0,001). This study demonstrates a significant correction of the longitudinal foot arch after a MCO. The novelty is attributed to the accurate degree of rotation assessment using WBCT. This information could be assistive to optimise a pre-operative planning

Summary. Our meta-analysis showed that pooled mean blood loss during spinal tumour surgeries was 2180 ml. Standardised methods of calculating and reporting intra-operative blood loss are needed as it would be beneficial in the pre-operative planning of blood replenishment during surgery. Introduction. The vertebral column is the commonest site of bony metastasis, accounting for 18,000 new cases in North America yearly. Patients with spinal metastasis are often elderly, have compromised cardiovascular status, poor physiological reserve and altered immune status, all of which render them more susceptible to the complications of intra-operative blood loss and associated transfusion. Currently no consensus exists regarding the expected volume of blood lost during metastatic spine tumour surgery with various papers quoting anywhere between 1L to 6L. Knowledge of the expected blood loss prior to surgery however is important as it facilitates pre-operative planning, intra- and post-operative management of fluid balance and blood transfusion. We conducted a meta-analysis of published literature on spine tumour surgery to answer the question: “What is the expected blood loss in major spinal tumour surgery for metastatic spinal disease?”. Methods. A comprehensive online search of the English literature using Medline, Embase, and the Cochrane Central Register of Controlled Trials was performed. We included articles published from 31 January 1992 until 31 January 2012. This initial online search yielded 98 relevant articles. Two senior investigators independently reviewed all abstracts. The full text of articles that were deemed eligible for further consideration obtained and reviewed. Eighty five articles were excluded at this stage, largely due to lack of clear blood loss data, leaving 13 eligible articles. A hand search of the reference lists of relevant articles yielded 5 more articles. A total of 18 articles were included in the final meta-analysis of blood loss data. Disagreements regarding eligibility of articles for analysis were resolved by consensus. Selected articles for final analysis were independently graded according to the Centre for Evidence-Based Medicine (CEBM) Levels of Evidence. We evaluated the possibility of publication bias by obtaining a funnel plot (created by plotting the sample size against the effect estimate). The Egger's regression asymmetry test was used to assess the existence of publication bias. Results. Eighteen selected articles had a total of 785 patients who had undergone major spine tumour surgery for metastatic spinal disorders. The pooled estimate of the blood loss occurring during spinal tumour surgeries was calculated to be 2180ml (95%CI: 1805–2554ml). Apart from two studies which reported significant mean blood loss of more than 5500 ml, the resulting funnel plot suggested absence of publication bias. This was confirmed by Egger's test which did not show any small-study effects (p=0.119). However, there was strong evidence of heterogeneity between studies with I2=90% (p<0.001). Conclusions. The expected blood loss of a patient undergoing major surgery for spinal tumour constitutes more than a third of the circulating blood volume in a typical cancer patient with significantly impaired physiological reserve. Moreover, cases of catastrophic blood loss exceeding 5L exist in almost every series evaluated in this paper, with some reaching as much as 17–18L. Blood loss is a significant problem during spine tumour surgery and concerted effort is needed to address it

Introduction. The purpose of this study was to examine if Sugioka's transtrochanteric rotational osteotomy (TRO) of the femoral head could be a valid option in treating idiopathic osteonecrosis of the femoral head. Methods. Thirty-two TROs performed in 29 patients between 1985 and 2006 were studied. Patient age at operation ranged from 16 to 56 years (average, 36 years). Thirteen hips were in women and 19 hips in men. Height was 165 cm and weight 63 kg (Body Mass Index 23) on average. Risk factors were corticosteroid use in 18 hips and excessive alcohol consumption in 15 hips (2 of them had both backgrounds), while neither of them was found with 1 hip. Bilateral hips were affected in 19 patients and 3 of them underwent bilateral TROs sequentially. The femoral head was rotated anteriorly in 26 hips and posteriorly in 6 hips. For fixation of the osteotomy site, large femoral screws had been used till 1995 (Group 1, 9 hips), and since 1996 an AO angle plate or a compression hip screw has been used (Group 2, 13 hips). Since 2003, pre-operative planning was performed more meticulously and the distal part of the joint capsule was cut after osteotomy as described by Atsumi (Group 3, 10 hips). The average follow-up period was 6.5 years (range, 2 to 21 years). Results. The average Japanese Orthopaedic Association hip score was 55 points pre-operatively, 63 points at 1 year, and 61 points at the latest follow-up. With pain increase, re-collapse of the rotated femoral head, fracture of the proximal fragment, nonunion, trochanteric detachment, joint space narrowing, osteoarthritic changes, or infection as the endpoint, the survival rate was 58% at 1 year, 53% at 4 - 9 years. The endpoint developed in 14 hips (re-collapse of the rotated femoral head in 9, fracture of the proximal fragment in 3, joint space narrowing in 1, and infection in 1). The changes in the surgical techniques were suggested to have improved the 3-year survivorship: 25% in Group 1, 54% in Group 2, and 74% in Group 3. The 4- to 9-year survival of this procedure was 53%. The majority of the endpoints developed within the first year, which may suggest that most of them were surgery-related. Conclusion. This procedure requires precise and meticulous precautions in pre-operative planning, preservation of the posterior column vessels during surgery, capsulotomy, and after-treatment. With those precautions, this procedure could be a valid joint-reserving option in treating idiopathic osteonecrosis of the femoral head. TRO is a highly difficult procedure and should be performed only by surgeons who have full training

Background. In certain clinical situations, complex local anatomy and limitations of surgical exposure can make adequate and bone tumor ablation, resection and reconstruction very challenging. We wished to review our clinical experience and accuracy achieved with entirely virtually planned single stage tumor ablation/resection and reconstructions. Methods. We report 6 cases of bone tumors in which tumor removal (by radio-frequency (RF) ablation and/or resection) and subsequent reconstruction were based entirely on pre-operative virtual analysis and planning. All interventions were accomplished with specifically designed and pre-operatively manufactured 3D-printed drill & resection guides. Immediate subsequent defect reconstruction was either performed with a precisely matching allograft (n=1) or composite metal implant (n=5) consisting of a defect specific titanium scaffold and multiple integrated fixation features to provide optimal immediate stability as well as subsequent opportunity for osseointegration. We reviewed the sequence of all procedural steps as well as the accuracy of each saw blade or drill trajectory by direct intra-operative measurement, post-operative margin status and virtual comparison of pre- and post-operative CT scans. Results. Intra-operative application/assembly of the resection guides could be accomplished with relative ease in all cases, permitting quick and efficient reproduction of the planned osteotomies as well as RF-probe trajectories with a high degree of accuracy. Histologically all resection margins were negative as planned except in one case where one pelvic resection was extended due to intraoperative concern of possible local tumor progression. All implants could be placed as planned, with post-operative imaging demonstrating satisfactory implant position. Virtual analysis of post-operative CT scans confirmeded minimal deviation of final implant position from the pre-operative plan. Conclusion. Reliable, accurate placement of tumor biopsy/ablation tracts and resection planes and their optimal alignment with respect to critical structures, tumor extent and desired preservation of unaffected bone is the most challenging and time consuming step during the analysis and planning phase. However it is also the crucial step with regard to subsequent design and production of clinically and oncologically meaningful case-specific drill/resection guides and implants. If these prerequisites are met, computer assisted virtual planning along with 3Dprinting-technology can afford high intraoperative accuracy, contribute to increased intra-operative surgeon confidence and decreased operative time

Background. A calcaneal medial osteotomy (CMO) is a surgical procedure frequently performed to correct a valgus alignment of the hindfoot. However currently little is known on its accurate influence on hindfoot alignment (HA). Aim. To assess the influence of a CMO on HA in both 2D and 3D measurements using weightbearing CT (WBCT). Methods. Twelve patients with a mean age of 49,4 years (range 18–67yrs) were prospectively included. Indications for surgical correction by a CMO with a solitary translation of the calcaneus consisted of an adult acquired flat foot stage II (N=10) and a talocalcaneal coalition (N=2). Fixation of the osteotomy was performed either using a step plate or double screw. A WBCT was obtained pre- and post-operative. HA was assessed by an angle between the anatomical tibia axis and the axis connecting the inferior calcaneus point and the middle of the talus in the coronal plane (HA. 2D. ) using Curvebeam® software. The tibia in the HA was separately assessed by the anatomical tibia axis (TA. X 2D. ). The same method was translated in 3D using 3-Matic® software with a Cartesian coordinate system originating in the inferior point of the calcaneus (HA. 3D. and TA. x 3D. ). Results. Both the mean pre-op HA. 2D. =12.8°± 4.5 and HA. 3D. =21.1°± 8.4 of valgus improved significantly post-operatively to a HA. 2D. =4.2°±4.5 and a HA. 3D. =11,9°± 6.1 (P < 0.001). Additionally, the mean pre-op TA. X 2D. = 4°± 2.6 and TA. X 3D. = 7,2 °± 3.2 showed a significant improvement to a TA. X 2D. = 3.1°± 2.7 and a TA. X 3D. = 6.1 °± 3.4 post-operatively (P < 0.05). The inter-rater reliability of the 2D measurement method with a mean ICC. HA2D. =0.74 and a mean ICC. TA2D. = 0.77 showed to be lower when compared to the 3D measurement method with a mean ICC. HA3D. =0.94 and a mean ICC. TA3D. =0.89. Conclusion. This study shows an effective correction of the valgus position from the calcaneus measured both in 2D and 3D when using a surgical CMO. The novelty is the marked influence on the tibia, which could now be accurately assessed using a weightbearing CT and additional 3D measurements. This resulted in 10% of the achieved HA correction, when analyzed both in 2D and 3D. This information could be of use when performing a pre-operative planning of a hindfoot deformity

Background. Recent studies have suggested that full-limb radiographs are more accurate and sensitive than short film radiographs for pre-operative measurement of the anatomical angles required to achieve optimal knee alignment in Total Knee Arthroplasty (TKA). However, there are drawbacks associated with their use including excess radiation to the pelvic organs, the need for specialised radiography equipment and increased cost. Given these drawbacks, we compared the use of MRI scans, a commonly performed pre-operative investigation, with short film knee radiographs for measurement of knee alignment. Objective. To investigate whether knee alignment measurements made on MRI scans correlate with those measured on short film knee radiographs in patients with osteoarthritic knees. Methods. We retrospectively reviewed short film knee radiographs and MRI scans of 50 patients with knee osteoarthritis. The plain radiographs had to be performed whilst weight bearing. The MRI scans were performed supine and non-weight bearing. The exclusion criteria included previous trauma to the knee, previous TKA and previous fracture of the lower limb. 4 angle measurements defined by The American Knee Society: alpha, beta, sigma and gamma were measured using each of the 2 modalities. Kolmogorov-Smirnov and two- tailed paired t-tests were used for statistical analysis of the results. Pearson correlation coefficient was used for the measure of dependence. Results. The alpha, beta, sigma and gamma angles obtained using the MR images were different to those obtained using short film weight bearing knee radiographs by −3°± 1° (p < 0.001), 1° ± 3° (p=0.002), 1° ± 3° (p=0.047) and 1° ± 4° (p=0.113) respectively. There was a weak correlation between the MRI based method and the radiographic method in measuring all 4 angles. Conclusions. Our results have shown that the angular measurements performed on MR images should be interpreted with caution as they may vary depending on the MRI slice selected for evaluation. The differences observed and the weak correlation between the 2 modalities may be due to the different scopes used for determining the femoral or tibial axes. The measurements obtained using the plain radiographs were interpreted using a single 2D projection of a 3D structure. However, the measurements of the MR images were evaluated using a 2D image of a slice through a 3D structure. In conclusion, the use of MRI scans for pre-operative planning in TKA may not be advisable at this stage as the angular measurements obtained using the MR images were poorly correlated to those obtained using plain radiographs

Four-dimensional computed tomography (4DCT: three dimensional + time) allows to measure individual bone position over a period of time usually during motion. This method has been found useful in studying the joints around the wrist as dynamic instabilities are difficult to detect during static CT scans while they can be diagnosed using a 4DCT scan [1]–[3]. For the foot, the PedCAT system (Curvebeam, Warrington, USA) has been developed to study the foot bones under full weight bearing, however its use is limited to static images. On the contrary, dynamic measurements of the foot kinematics using skin markers can only describe motion of foot segments and not of individual bones. However, the ability to measure individual bone kinematics during gait is of paramount importance as such detailed information could be used to detect instabilities, to evaluate the effect of joint degeneration, to help in pre-operative planning as well as in post-operative evaluation. The overall gait kinematics of two healthy volunteers were measured in a gait analysis lab (Movement Analysis Lab Leuven, Belgium) using a detailed foot-model (Oxford foot model, [4]). The measured plantar-dorsiflexion and in-eversion were used to manipulate their foot during a 4D CT acquisition. The manipulation was performed through a custom made foot manipulator that controls the position and orientation of the foot bed according to input kinematics. The manipulator was compatible with the 4D CT Scanner (Aquilion One, Toshiba, JP), and a sequence of CT scans (37 CT scans over 10 seconds with 320 slices for each scan and a slice thickness of 0.5 mm) was generated over the duration of the simulation. The position of the individual bones was determined using an automatic segmentation routine after which the kinematics of individual foot bones were calculated. To do so, three landmarks were tracked on each bone over time allowing to construct bone-specific coordinate frames. The motion of the foot bed was compared against the calculated kinematics of the tibia-calcaneus as the angles between these two bones are captured with skin markers. There is high repeatability between the imposed plantar/dorsiflexion and inversion/eversion and the calculated. Although the internal/external rotation was not imposed, the calculated kinematics follow the same pattern as the measured in the gait-analysis lab. Based on the validation of the tibia-calcaneus, the kinematics were also calculated between four other joints: tibia-talar, talar-calcaneus, calcaneus-cuboid and talar-navicular. Repeatable measurements of individual foot bone motion were obtained for both volunteers. The use of 4D CT-scanning in combination with a foot manipulator can provide more detailed information than skin marker-based gait-analysis e.g. for the study of the the tibia-talar joint. In the future, the foot manipulator will be tested for its sensitivity for specific pathologies (e.g. metatarsal coalition) and will be further developed to better resemble a real-life stance phase of gait (i.e. to include isolated heel contact and toe off)