DDH incidence falls from 5–20 per 1000 at birth to 1–2 per 1000 by 3 weeks. Some patients present late and frequently require surgical intervention. If the hip cannot be contained without tension, these children undergo open reduction +/− a femoral shortening, varus and derotation osteotomy. Salter’s osteotomy, may be performed either at index surgery or later in the presence of persisting acetabular dysplasia. Our aim was to see if we could predict which cases of persistent DDH would require both femoral and pelvic surgery to contain the affected hip, using a single plain AP radiograph of the pelvis in the outpatient setting. We performed a retrospective study of all children older than 18 months with persistent DDH of one or both hips, over the last 5 years, who had undergone femoral and/or pelvic surgery to contain the hip. Plain AP pelvic radiographs were standardised according to the method described by Tonnis. From these radiographs the acetabular indices and child’s age in months, were recorded. Syndromic and children with non-standard x-rays were excluded. Thirty nine hips (34 female, 5 male), age range of 18–102 months, formed our study group. 53% of hips having femoral surgery later required pelvic surgery for persisting acetabular dysplasia. Examining the data in these cases, the difference between the acetabular index of the normal and affected hip was always greater than 20 degrees and the child’s age in months. Using this method we conclude that it is possible to predict which cases of persistent DDH will require pelvic surgery to fully contain the affected hip and that this can be done with one AP pelvic radiograph in the outpatient clinic. The benefit is avoidance of unnecessary pelvic osteotomies, and being able to determine the cases which should have a pelvic osteotomy at index procedure

Aim: Advances in digital imaging have allowed three dimensional reconstructions to be derived from CT images which greatly improve understanding of complex deformities. Selective laser sintering (SLS) is used in the industrial setting to manufacture prototype models from Computer Aided Designs (CAD). This technology can be utilised to convert CT images into accurate three dimensional physical models of the human bony anatomy. This SLS modelling was used as an aid in the pre-operative planning of complex pelvic surgery. Materials and Methods: Standard pre-operative X-ray of the pelvis and a CT scan was undertaken. Using MIMICS software and selective laser sintering, models of these deformities could be made. The cases included bladder exstrophy and a complex developmental dysplasia of the hip with associated femoral head dislocation. The cost of this was comparable with a CT scan or MRI scan. Conclusion: These models provide invaluable visual and tactile information to the operating surgeon, accurately demonstrating the abnormal anatomy in an easily comprehensible manner. They allow estimation of the magnitude and degree of corrections necessary and evaluation of bony deficiencies

Among the advanced technology developed and tested for orthopaedic surgery, the Rizzoli (IOR) has a long experience on custom-made design and implant of devices for joint and bone replacements. This follows the recent advancements in additive manufacturing, which now allows to obtain products also in metal alloy by deposition of material layer-by-layer according to a digital model. The process starts from medical image, goes through anatomical modelling, prosthesis design, prototyping, and final production in 3D printers and in case post-production. These devices have demonstrated already to be accurate enough to address properly the specific needs and conditions of the patient and of his/her physician. These guarantee also minimum removal of the tissues, partial replacements, no size related issues, minimal invasiveness, limited instrumentation. The thorough preparation of the treatment results also in a considerable shortening of the surgical and of recovery time. The necessary additional efforts and costs of custom-made implants seem to be well balanced by these advantages and savings, which shall include the lower failures and revision surgery rates. This also allows thoughtful optimization of the component-to-bone interfaces, by advanced lattice structures, with topologies mimicking the trabecular bone, possibly to promote osteointegration and to prevent infection. IOR's experience comprises all sub-disciplines and anatomical areas, here mentioned in historical order. Originally, several systems of Patient-Specific instrumentation have been exploited in total knee and total ankle replacements. A few massive osteoarticular reconstructions in the shank and foot for severe bone fractures were performed, starting from mirroring the contralateral area. Something very similar was performed also for pelvic surgery in the Oncology department, where massive skeletal reconstructions for bone tumours are necessary. To this aim, in addition to the standard anatomical modelling, prosthesis design, technical/technological refinements, and manufacturing, surgical guides for the correct execution of the osteotomies are also designed and 3D printed. Another original experience is about en-block replacement of vertebral bodies for severe bone loss, in particular for tumours. In this project, technological and biological aspects have also been addressed, to enhance osteointegration and to diminish the risk of infection. In our series there is also a case of successful custom reconstruction of the anterior chest wall. Initial experiences are in progress also for shoulder and elbow surgery, in particular for pre-op planning and surgical guide design in complex re-alignment osteotomies for severe bone deformities. Also in complex flat-foot deformities, in preparation of surgical corrections, 3D digital reconstruction and 3D printing in cheap ABS filaments have been valuable, for indication, planning of surgery and patient communication; with special materials mimicking bone strength, these 3D physical models are precious also for training and preparation of the surgery. In Paediatric surgery severe multi planar & multifocal deformities in children are addressed with personalized pre-op planning and custom cutting-guides for the necessary osteotomies, most of which require custom allografts. A number of complex hip revision surgeries have been performed, where 3D reconstruction for possible final solutions with exact implants on the remaining bone were developed. Elective surgery has been addressed as well, in particular the customization of an original total ankle replacement designed at IOR. Also a novel system with a high-tibial-osteotomy, including a custom cutting jig and the fixation plate was tested. An initial experience for the design and test of custom ankle & foot orthotics is also in progress, starting with 3D surface scanning of the shank and foot including the plantar aspect. Clearly, for achieving these results, multi-disciplinary teams have been formed, including physicians, radiologists, bioengineers and technologists, working together for the same goal

From the appearing of the first works of R. Judet, E. Letournel, M. Tile up to this day, the methods of pelvic surgery changed cardinally. These operations are technically complicated and accompanied by blood loss. That’s why the low-invasive surgical methods including endoscopic approach are perspective. The endoscopic methods of reposition and osteosynthesis offer advantages which are expressed in increasing of injury visualization, reduction of surgical incisions and fast postoperative restoration. A surgeon using the method of osteosynthesis needs endoscopic skills and thorough knowledge of standard surgical approaches. We have the experience of the treatment of 12 patients. We consider that the indications for these operations are not only a type of pelvic injury, but also anatomico-technical moment: an opportunity of creating of workspace. We have 2 techniques:. endoscopic osteosynthesis with using of pelvioscope;. optical endoscopic osteosynthesis. In any case, it is necessary to create the workspace from a small incision above the injury region by the method of tissue pneumotization. Fracture reposition is realized using a fracture table and reducing attachments. Osteosynthesis is immediately carried out with both standard and original steel constructions using the special tools that we developed and produced (ports, drill, screwdrivers etc.). The intraoperative blood loss was not more than 150 ml in all cases and in the postoperative period in drains–not more than 100 ml. The promotion of the patients was realized by the standard methods. There were no complications. The good functional result was in all cases. We think that further development of such techniques will allow to activate pelvic surgery on the new qualitative level

Objective: A floating hip, e.i. combination of pelvic or acetabulat fracture with ipsilateral femoral fracture is uncommon condition, but posing considerable problems such as how to manage each component of the injury and what are the treatment priorities. The aim of the syudy is to report our experience with surgical treatment of traumatic floating hip. Material and methods: For the 4-year period in our institution 15 patients with floating hips (10 mails, 5 females, average age 38 years) were treated operatively. There were 10 unstable pelvic ring disruptions B and C types and 5 displaced acetabular fractures, combined with 2 neck, 11 shaft and 2 supracondylar femoral fractures. Six patients were operated simultaneously for both components and in the rest definitive pelvic surgery were done at a second stage. pelvic girdle was stabilized by a variety of methods: anterior sacro-iliac plates, iliosacral lag screws, transsacral posterior plaates. Acetabular fractures were all treated by ORIF. For femoral fractures nailing was done in 8 cases, plating in 5 and cervical screw fixation in 2. Results: All fractures healed in time. Two superficial femoral infections resolved after local care. Results for pelvic injuries were estimated according to Pholemann score and for acetabular fractures – to Matta scale. In respect to pelvic fractures 5 ecxellent, 3 good and 2 poor results were noted, and regarding acetabular fractures 3 exccelent, 1 satisfactory and 1 poore results. All femoral fractures united in good position. Overall final outcome was excellent in 8, good in 3, fair in 1 and poor in 3 patients. Conclusions: Surgical treatment is a method of choice for a floating hip. ORIF of pelvic ring and locking nailing of the femur result in best outcome. Simultaneous procedure provides more rapid recovery, but should be carried out only in stable patients. If staged surgery is planned, stabilisation of the femur should be done prior to definitive pelvic fixation in order to facilitate later pelvic surgery

The anterior pelvic plane (APP) is used as a reference in various pelvic surgeries in orthopaedics. Current methods for identifying the APP are limited in accuracy and efficiency. A quick and accurate method for registering the pelvis orientation can be very useful. Previously, we have introduced a Tracked C-arm (TC-arm) system for use with any C-arm fluoroscopy for producing spatially calibrated imaging views. This system has been tried for estimating the APP. Early results, however, has shown limited repeatability in identifying the anterior superior iliac spine (ASIS) landmarks. This study improves the previous algorithms for a robust registration of the APP. A Sawbone pelvis was used, and its APP was marked by radio-dense ball-bearings. In the new addition, the TC-arm allowed segmenting the ASIS in an interactive user-interface by taking guidance from a reference line tangential to the ipsilateral pubic tubercle for marking the most anterior point on the iliac-crest. The imaging and analysis was repeated 10 times. The results were compared to reconstruction of the fiducial markers placed on the true APP. Accuracy of 1.4° and 4.4° were found for registering the pelvic tilt and rotation, correspondingly. The overall accuracy and precision of registration of the APP were 4.7° and 0.82°, correspondingly. The new method showed 7.5 times improvement in repeatability of measuring the pelvic tilt (SD<0.4°) compared to the previous fluoroscopic methods. This technique addresses an important challenge in estimation of the pelvic bone which is crucial for reliable device placement and producing standard radiographic views in surgery

Beside spine and pelvis surgery, computer-assisted guidance systems are not used frequently for musculoskeletal injuries. Main reason is the dependence on a fixed reference array that must be firmly attached to all moving parts. We investigated a novel fluoroscopy-based image guidance system in orthopaedic trauma surgery that uses a different technique. This was a prospective, not randomised single centre case series at a level I trauma centre. 45 patients with 46 injuries (foot 12, shoulder 10, long bones 7, hand and wrist 7, ankle 7, spine and pelvis 4) were included. Different surgical procedures were examined following the basic principles of the AO/ASIF. Main outcome measurements were the number of trials for implant placement, total surgery time, usability via user questionnaire and system failure rate. Furthermore we wanted to test the ability of the new system to be integrated in existing surgical workflows. In all cases, the trajectory function was used, inserting a total of 56 guided implants. The trajectory was the most popular feature used by surgeons (n=43, 93.5%), followed by the length measurement tool (n=29, 63%) and the bending function (n=17, 37%). The functions could be freely activated by the performing surgeon. The system failed when used in pelvic and spinal injuries, resulting in a total failure rate of 6.5% (n=3) of all included cases. The overall usability was rated as good, scoring 84.3%. This study examined the clinical application of a fluoroscopy-based image guidance system for different musculoskeletal injuries. Its major advantage is the high integrability in the accustomed surgical workflow and its connectivity with existing technical equipment. It can hardly be compared to known navigation solutions, since instruments are not tracked and fixed reference arrays are not required. Expected advantages should be explored in randomised studies

Introduction. Periacetabular osteotomy has been described as an effective way of treating symptomatic hip dysplasia. We describe a new minimally invasive technique using a modification of the Smith Peterson approach. Patients/Materials & Methods. 189 consecutive patients operated on between March 2010 and March 2013 were included in the study. Patients who had undergone previous pelvic surgery for DDH were excluded. There were 174 females and 15 males. The mean age was 31 years (15–56) and the mean duration of follow-up was 29 months (14 – 53 months). 90% of cases were Tonnis grade 0 or 1. Twenty-three patients were operated on for primary acetabular retroversion. Functional outcomes were assessed using the NAHS, UCLA and Tegner activity scores. The surgical procedure is performed through an 8–10 cm skin crease incision; a soft tissue sleeve is elevated from the anterior superior iliac spine. The interval medial to the rectus femoris is developed. The hip joint is not opened and fixation of the osteotomy was with three 4.5mm cortical screws. A cell saver was routinely used. Results. For the dysplasia group the mean pre-operative lateral centre edge angle was 14.2degrees (−5degrees to 30degrees) and the mean acetabular index was 18.4degrees (4degrees to 40degrees). Post-operatively these were 31degrees (18degrees to 46degrees) and 3degrees (−7degrees to 29degrees) respectively. An allogenic blood transfusion was required in 3 patients (1.5%). The mean duration of surgery was 105 minutes. There were no major nerve or vascular complications and no wound infections. At the time of last follow-up, we noted a significant improvement in functional outcome scores: UCLA improved by 2.31 points, Tegner improved by 1.08 points, and the NAHS improved by 25.4 points. Conclusion. We have found this approach to be safe and effective, facilitating early recovery from surgery

Aims

The aim of this study was to investigate the association between fracture displacement and survivorship of the native hip joint without conversion to a total hip arthroplasty (THA), and to determine predictors for conversion to THA in patients treated nonoperatively for acetabular fractures.

Stoppa approach has recently been adapted for pelvic surgery as it allows direct intra-pelvic reduction and fixation of the quadrilateral plate and anterior column. We report our early experience, indications and complications with this exposure introduced in 2010 in our tertiary unit. A Retrospective review of all Stoppa approaches in pelvic-acetabular fixations was performed from a prospectively maintained database. Of the 25 patients, mean age 40 years (range 15–76), who underwent pelvic-acetabular fixation using Stoppa approach, 21 patients had mean follow up of 7.3 months (1–48 months). All except 24% of patients had one or more additional systemic injury some requiring additional surgery. There were 6 acetabular fractures, 13 pelvic ring injuries and 6 combined fractures. Mean injury-surgery interval was 9 days (range 3–20). 8 patients had an isolated Stoppa approach whilst the remaining others also had an additional approach. Mean surgical time was 239 minutes. Anatomical reduction was achieved in 96% (24/25) cases. There was 1 minor intra-operative vascular injury, repaired immediately successfully, and no late wound infections, or other visceral complications. One patient reported new onset sensory numbness which resolved after the first review. Two patients reported erectile dysfunction thought to be caused by the initial injury. One patient had asymptomatic plate loosening. None required revision surgery. Despite the obvious learning curve, we found this approach safe and it did not compromise accuracy of reduction in well selected patients, but early surgery within 10–14 days is recommended to aid optimal reduction

Background: Paralysis of the crural nerve secondary to a compressive haematoma of the psoas in the pelvis is a well-known complication of anticoagulant therapy. This complication has also been described after hip or pelvic surgery. Its occurrence in a context of trauma is exceptional. Case report: A 16-year-old female adolescent sought emergency care for total deficit of knee extension. The patient had an enlarged painful knee subsequent to a skateboard fall. She reported knee trauma involving the patella and a direct shock to the homolateral hip, on the trochanter. Physical examination confirmed the knee and hip pain. Rest was advised. One and a half month after the accident, the patient again consulted for total deficit of active knee extension. The initial diagnosis suggested was posttraumatic rupture of the patellar tendon. An emergency MRI was normal, ruling out this diagnosis. More attentive physical examination revealed the presence of a complete paralysis of the quadriceps muscle by crural nerve palsy. MRI of the pelvic region revealed the presence of a voluminous haematoma of the psoas compressing the crural nerve. Emergency evacuation of the haematoma was performed. The patient underwent rehabilitation for one year and achieved progressive and complete recovery of the quadriceps function. An electromyogram obtained at one year was normal. Conclusion: This was an exceptional case of crural nerve palsy secondary to a posttraumatic haematoma of the psoas, with no notion of anticoagulation therapy. The initial knee injury was misinterpreted as involving a local patellar problem but in reality had caused a paralysis of the quadriceps muscle. MRI provided the diagnosis of psoas haematoma

Introduction. Reported incidence of DVT after spinal surgery ranges from 0-15% and PE 0.5-2.7%. Theoretically, manipulation of the vessels and venous stasis caused by retraction during anterior lumbar inter-body fusion may increase the propensity for thrombosis. The reported incidence of DVT and PE following major abdominal and pelvic surgery are high (up to 23%) and all these patients routinely receive chemical prophylaxis. Aim. Should patients undergoing ALIF surgery receive chemical prophylaxis routinely?. Materials and Methods. Retrospective review of ALIF procedures done between Jan 2007- Jan 2010. Review of case notes, radiology reports and telephone call to the patients to exclude DVT. Total of 76 patients underwent ALIF during this period. Forty six were female(60.5%) and 36 were 2 level fusions(47%). L5-S1 being commonly fused (76%) followed by L4-L5 (23%). Average surgical time from theatre records is 115 minutes(31-369 minutes). All patients received mechanical prophylaxis in the form of thigh length TED stockings. None of the patients were on treatment for DVT prior to surgery. Results. Three patients (3.9%) had Doppler proved DVT which required anticoagulation treatment. There was no reported incidence of PE. Discussion. There is no definite evidence in the literature to suggest ALIF surgery has higher incidence of thromboembolic complications, though theoretical possibility of increased risk. Current study suggests that incidence is 3.9% with mechanical prophylaxis alone which is very small when compared to incidence after major abdominal, pelvic or gynaecological procedures. Our small study sample suggests routine use of chemical prophylaxis to reduce the risk of DVT for anterior lumbar inter-body fusion is not justified

Introduction. Lumbar spinal pain can be a consequence of discogenic pain. After failure of conservative management, lumbar fusions are popular and considered the gold standard. However, these techniques are associated with significant morbidity. A percutaneous trans-sacral technique may address these for L4/L5 and/or L5/S1 alone spinal fusions. Our unit has adopted this technique and presents our initial experience of 51 patients and preliminary results. Method. Patients with a confirmed clinical and radiological evidence of degenerate intervertebral disc with or without prior surgical intervention were selected. Patients with a history of pelvic surgery/radiotherapy were excluded. Data was collected prospectively using the Global Patient Outcome Scoring System and Oswestry Disability Index (ODI) scores at clinical follow-up. Results. 51 patients received the procedure and 30 achieving a minimum of 6 months follow-up. Patients had a median age of 46(range 20-78) and included 19 male and 32 females with on average 40 months of pain. The mean ODI score improved after surgery from pre-operative levels 52.9(SEM 3.0) to 6 month scores of 38.4(SEM 3.9), t(29)=4.2, p<0.0002 . This difference remained statistically significant at 12 month follow-up with a mean ODI scores 34.3 (SEM 5.2), t(18)=4.37, P<0.0004 (Mean difference of 21.1 SEM 4.8). A sub-analysis of confounding factors identified patients with previous surgery, claiming state benefits, pursuing litigation, mainly leg pain and requiring pedicular fusion failed to achieve statistical significance. Patients receiving a 360 degree fusion with facet screws alone improved sooner and achieving a mean difference in ODI score of 27.6(SEM 8.2). Conclusion. Our initial results confirm this to be an effective alternative treatment modality for lumbar spine fusion in the management of primary discogenic back pain. Patients receiving 360 degree fusion and not claiming state benefits or pursuing litigation appear to have a better outcome

In 1996 the quality of the early management of 100 consecutive patients referred to a regional pelvic and acetabular unit between 1989 and 1992 was studied. The management of these patients was assessed in four specific areas, and guidelines were laid down. It was found that in 56% of patients the early management did not meet these suggested standards, with 34% having deficiencies in more than one area. These results were presented, published and circulated to referring hospitals. Five years later, the early management of a further 100 consecutive referrals was assessed using these same guidelines. The treatment of 57% of patients still did not reach the guideline standards, but the number with problems in more than one area fell to 20%. There has been some improvement in the early management of pelvic and acetabular injuries. The use of external fixators to control severe haemorrhage increased, but frames were often poorly applied. Wider access to CT scanners has reduced delays in definitive imaging. Associated injuries are still regularly overlooked, and occasionally treatment of ipsilateral hip or femur fractures compromises pelvic surgery. Early communication with the specialist centre is encouraged but unfortunately delays in referral are still common

Aim: To demonstrate that the conservative management of meralgia paraesthetica in children is effective. Method: Clinic case-notes of the senior author (CB) were retrospectively searched between January 1997 and February 2007 to identify cases of meralgia paraesthetica. Sixteen cases were discovered in fourteen patients, 6 right, 6 left, and 2 bilateral. Four patients had had previous pelvic surgery and two combined pelvic and femoral osteotomy for developmental dysplasia of the hip. One underwent bilateral pinning for slipped upper femoral epiphyses. Clinical symptoms were assessed subjectively. All patients were initially managed conservatively with NSAIDs and counselled to avoid tight fitting clothing across the waist. If symptoms had failed to settle at follow-up a local anaesthetic/steroid injection was administered to the site of maximal tenderness. Surgical decompression was performed for intractable cases. Results: There were 10 females and 4 males, with a mean age of 13.6 years (8–17). Mean follow-up was 15 months (1–50). Eleven cases (68.8%) improved with conservative management and a further three cases improved following a local anaesthetic/steroid injection. Two cases (12.5%) who did not improve with these measures underwent surgical decompression with subsequent improvement in symptoms. No side effects were reported from the either the steroid injection or surgical decompression. Conclusions: There is no current evidence supporting the management of meralgia paraesthetica in children. In adults, this elusive diagnosis is managed conservatively to good effect. This retrospective study demonstrates that conservative management is also effective in paediatric patients. In those cases where symptoms prove intractable, surgical decompression produces clinical improvement

Introduction: The incidence, outcome and recovery of operatively managed pelvic ring fractures were studied from a three-year cohort of patients. No previous published studies have reviewed the factors influencing the outcome of operative stabilization on the neural function and natural recovery in these potentially devastating injuries. Methods: This retrospective case series study of 489 referrals to a tertiary referral unit, from 1st Jan 2004 to 31st Dec 2006, identified 42 (8.6%) patients who had sustained pelvic ring injuries with associated neural injuries. Each pelvic injury was classified using the Tile and Burgess & Young classifications, neural injuries were classified as either complete or incomplete and the degree of post-operative skeletal displacement was quantified using radiographs. A mean clinical and radiographic follow up of 3.5 years was achieved and statistical analysis was performed used chi-squared (SPSS). Results: The mean age of patients with neural injuries was 28 years, 32 (76%) were male and 37 (88%) had unstable, Tile type C, fracture patterns. The mean delay from time of injury to time of pelvic surgery was 11 days (range 3 – 42 days). Full resolution of neural symptoms was observed in 16 (38%) patients, with a mean fracture reduction of < 6mm. Incomplete improvement was observed in 11 patients and 15 patients had ongoing complete lumbosacral palsy. Patients who failed to achieve full resolution of neural function had a mean fracture or sacro-iliac joint reduction of 8.8 mm and the mean delay to surgery was 24 days. Discussion: Pelvic ring injuries with an unstable fracture pattern are associated with a high incidence of neural injury. Accurate fracture reduction and stabilization, achieved without a prolonged delay, creates a better environment to achieve a good neural outcome. In such injuries with complete nerve palsy, delayed and suboptimal surgical reduction predicts a poor prognosis

Introduction: Open reduction and internal fixation (ORIF) is considered the treatment of choice in dislocated unstable pelvic fractures. However ORIF has several drawbacks, such as considerable soft tissue trauma, a substantial intraoperative blood loss and up to 25% infectious complications. To overcome these problems mini-invasive osteosynthesis techniques have been developed. Methods: Analysis of the problem revealed necessary changes on the level of intraoperative imaging, surgical approach, reduction devices and technology integration. Intraoperative imaging with computertomography gives all the time an appropriate representation of the real position of bony fragments of the pelvis. A new type of axial reduction clamps allows fracture reduction through small incisions. Preshaped plates can be pushed underneath the soft tissue. Computer navigation helps to place screws in a save manner percutaneously. Results: We present the setting of a new multifunctional image guided therapy suite, which is an optimal platform for mini-invasive treatment of fresh dislocated anterior and posterior pelvic ring fractures, as well as for percutaneous treatment of pelvic non unions. The technique of reduction and fixation of an anterior pelvic ring fracture through two small incisions instead of a full ilio-inguinal approach is shown. A case of percutaneous bone grafting of a delayed union of the sacrum is presented. Conclusions: Mini-invasive osteosynthesis techniques require appropriate imaging tools, new reduction devices and most notably special skills. However all together may reduce severe side effects of conventional pelvic surgery

Aims

The use of 3D printing has become increasingly popular and has been widely used in orthopaedic surgery. There has been a trend towards an increasing number of publications in this field, but existing literature incorporates limited high-quality studies, and there is a lack of reports on outcomes. The aim of this study was to perform a scoping review with Level I evidence on the application and effectiveness of 3D printing.

In orthopaedic surgery, as in many other surgical fields, there is a clear tendency towards the use of minimally invasive procedures. These techniques are increasingly being implemented almost routinely for procedures such as spine and pelvis surgery. However, for fracture treatment and for applications involving small bones, such as hand and foot surgery, these systems are hardly ever used. We introduce a new system for image based guidance in traumatology. We included 20 patients with a fracture of the fifth metatarsal. They were randomised on admission into two groups. Ten patients in the metatarsal group were operated conventionally and ten were operated with the assistance of a new image guidance system. This system is based on 2D-fluoro images which are acquired with a conventional c-arm and are transferred to the system workstation. After detecting marked tools, it can be used to display trajectories for K-wire guidance in the c-arm shot. The average duration of surgery (time from incision to suture) in the image-based group was 12.7 minutes ± 5.5 (min. 6, max. 23), in the conventional group it was 17 minutes ± 6.5 (min. 7, max. 28) (p=0.086). The average duration of radiation was 18 seconds ± 8.5 (min. 6, max 36) in the image-based group vs. 32.4 seconds ± 19.4 (min. 12, max. 66) in the conventional group (p=0.057). An average of 4.7 C-arm shots ± 2 (min 2, max 9) were necessary in the image-based group to position the K-wire. For the conventional group, 8.2 shots ± 2.3 (min 4, max 12) were used (p=0.0073). It took 1.6 trials ± 0.7 (min.1, max. 3) to position the K-wire for the image-based procedures, in the conventional group 2.7 trials ± 0.9 (min. 1, max 4) were necessary (p=0.0084). There were no malfunctions or adverse events in any of the image-based navigational cases. No screws needed to be replaced in the image-based group. In the conventional group, two screws were replaced intra-operatively because they were too short in the control c-arm shot, and the screw threads did not bridge the fracture gap completely, leading to insufficient compression. In this pilot study with only a small sample size, the image-based guidance system could be integrated into the existing surgical workflow and was used for applications, where existing navigation systems are not commonly used. The technology gives the surgeon additional information and can reduce the number of trials for perfect implant positioning. This potentially increases the safety of the surgical procedure and spares intact bone substance which is essential for the footing of implants in small bones and fragment fixation. Whether these factors contribute to a reduction in complications or revision rate must be confirmed in larger prospective studies

Aims

Developmental dysplasia of the hip (DDH) describes a pathological relationship between the femoral head and acetabulum. Periacetabular osteotomy (PAO) may be used to treat this condition. The aim of this study was to evaluate the results of PAO in adolescents and adults with persistent DDH.