Radiographic cortical thickness parameters as predictors of rotational alignment in proximal tibial shaft fractures: a cadaveric study.

AIM: The treatment of tibial fractures with an intramedullary nail is an established procedure. However, torsional control remains challenging using intraoperatively diagnostic tools. Radiographic tools such as the Cortical Step Sign (CSS) and the Diameter Difference Sign (DDS) may serve as tools for diagnosing a relevant malrotation. The aim of this study was to investigate the effect of torsional malalignment on CSS and DDS parameters and to construct a prognostic model to detect malalignment. METHODS: A proximal tibial shaft fracture was set in human tibiae. Torsion was set stepwise from 0° to 30° in external and internal torsion. Images were obtained with a C-arm and transferred to a PC for measuring the medical cortical thickness (MCT), lateral cortical thickness (LCT), tibial diameter (TD) in AP and the anterior cortical thickness (ACT) as well as the posterior cortical thickness (PCT) and the transverse diameter (TD) of the proximal and the distal main fragment. RESULTS: There were significant differences between the various degrees of torsion for each of the absolute values of the examined variables. The parameters with the highest correlation were TD, LCT and ACT. A model combining ACT, LCT, PCT and TD lateral was most suitable model in identifying torsional malalignment. The best prediction of clinically relevant torsional malalignment, namely 15°, was obtained with the TD and the ACT. CONCLUSION: This study shows that the CSS and DDS are useful tools for the intraoperative detection of torsional malalignment in proximal tibial shaft fractures and should be used to prevent maltorsion.

[Open fractures]. / Offene Frakturen.

Open fractures are associated with a higher rate of infections and delayed fracture healing; therefore, in addition to fracture fixation, infection prevention and soft tissue management are also important. Administration of antibiotics should be carried out as early as possible and over 24-72 h depending on the injury. The initial debridement and assessment of the severity of injury determine the treatment strategy. Fracture fixation follows the general traumatological principles. Simple injury patterns can be treated by primary fixation and wound closure. With substantial contamination, loss of bone or extensive soft tissue damage, temporary fixation and temporary wound closure are carried out. The definitive treatment with soft tissue coverage should be performed within 72 h in order to reduce the risk of fracture-related infections. For osseous segmental defects, different approaches are available to restore bone continuity, depending on the size and soft tissue situation.

[All internal segmental transport in tibial bone defects: first experiences with the PRECICE bone transport system]. / "All-internal"-Segmenttransport bei Knochendefekt an der Tibia: erste Erfahrungen mit dem PRECICE Bone Transport System.

Bone loss of the distal tibia represents a major challenge for the treating surgeons and the reconstruction technique. This is particularly true for septic bone loss. Several techniques are available, ranging from callus distraction of Ilizarov frames and monorail techniques as well as transport with plates and nails; however, implants for internal segmental transport for bone defects have so far not been available. This case report describes worldwide the first reconstruction of a distal tibial defect by reconstruction of the major arterial flow path with flap coverage and all inside segmental transport using a motorized segmental transport nail without additional osteosynthesis or add-on module.

Modified less invasive anterior subcutaneous fixator for unstable Tile-C-pelvic ring fractures: a biomechanical study.

BACKGROUND: Operative procedures for unstable pelvic ring fractures remain controversially discussed. Minimally invasive treatment options for pelvic ring fractures have several benefits for the patient. But they can also provide disadvantages. Anterior subcutaneous pelvic fixation (INFIX) has shown promising biomechanical results in pelvic ring fractures, but there is a high complication rate of nerve injuries. An additional screw to the INFIX seems to be more stable. The aim of this study is to compare biomechanical stability of a new modified unilateral INFIX fixing the unilateral injured pelvic ring with the standard INFIX. METHODS: 24 composite synthetic full pelvises were used in this study. 4 groups each with a number of six pelvic specimens were randomly assigned. A C1.3-type pelvic fracture was made with an osteotomy of the sacrum and an osteotomy of the anterior pelvic ring. Fracture fixation was performed within the four groups: (1) unilateral INFIX, (2) "extended" unilateral INFIX + additional pubic ramus pedicle screw, (3) bilateral INFIX, (4) "extended" bilateral INFIX + additional pubic ramus pedicle screw. All specimens were cyclic loaded with 200 N until maximum of 300 N. Distance/dislocation of the fracture fragments were detected with 3D-ultrasound measuring system. Stiffness was calculated. RESULTS: Extended unilateral INFIX showed the lowest mean dislocation. Lowest rotational stability was displayed by the standard bilateral INFIX. A significant difference (P = 0.04) was shown between the extended unilateral INFIX and the "standard" bilateral INFIX in terms of rotational stability. Extended unilateral INFIX showed significantly improved stability of anterior fracture dislocation (P = 0.01) and unilateral INFIX showed the highest rotational stiffness. Anterior fixation stiffness of the unilateral INFIX was significantly improved using an additional symphysis/pubic ramus screw (P = 0.002). CONCLUSION: Extended unilateral INFIX (+ additional pubic ramus pedicle screw) is a feasible minimally invasive treatment for anterior pelvic ring fractures. Higher stability and lower probability of bilateral nerve damage is provided by the extended unilateral INFIX compared to the standard bilateral INFIX.

[Is it sensible to use fix and flap also in old age?] / Ist "fix and flap" auch im hohen Alter sinnvoll anwendbar?

In older patients the optimal treatment strategy of complex bone and soft tissue injuries represents a new challenge. Currently, two treatment approaches are in competition. Whereas the amputation of the limb represents a rapid solution including short postoperative hospitalization, limb preservation in cases of open fractures is frequently associated with prolonged hospitalization and sometimes unsatisfactory functional outcomes. Therefore, especially in old patients the advantages and disadvantages should be weighed up. A possible alternative to the currently frequently used multistep procedure for limb preservation with continuous negative pressure treatment is the fix and flap or emergency free flap approach. Based on the case of a convulsion trauma in an 85-year-old patient, this case report describes a treatment approach for Gustilo-Anderson type IIIc fractures using a fix and flap procedure for limb preservation.

Influence of Entrapment on Prehospital Management and the Hospital Course in Polytrauma Patients: A Retrospective Analysis in Air Rescue.

BACKGROUND: Entrapment is a challenging and crucial factor in the prehospital setting. Few studies have addressed whether entrapment has an influence on on-scene treatment or on the following hospital course. OBJECTIVES: Here we aimed to investigate the influence of entrapment on prehospital management and on the hospital course of polytrauma patients. METHODS: We performed a retrospective analysis of consecutive patients with an Injury Severity Score ≥16 and aged 16-65 years that were admitted between 2005 and 2013 to a Level I trauma center. Two groups were built: entrapped (E) and nonentrapped patients (nE). These groups were evaluated for multiple prehospital and clinical parameters, including on-scene time, prehospital interventions, and posttraumatic complications. RESULTS: There were 310 patients (n = 194 no entrapment [Group nE], n = 116 with entrapment [Group E]) enrolled. The on-scene time was significantly longer in Group E than Group nE. Moreover, this group received a significantly higher volume of colloidal solution. Regarding the Injury Severity Score and Abbreviated Injury Scale (AIS), there were no significant differences between the groups, except for the AISextremities, which was significantly increased in Group E. The overall hospital stay and the initial theater time were significantly longer in Group E than Group nE. No significant differences were present for the occurrence of systemic inflammatory response syndrome, multiple organ dysfunction syndrome, and acute respiratory distress syndrome, nor for Acute Physiology and Chronic Health Evaluation II and estimated and final mortality. CONCLUSION: In polytraumatized patients, entrapment has a minor influence on the outcome and treatment in the prehospital and hospital setting when using physician-based air rescue. However, entrapped patients are prone to sustain more severe trauma to the extremities.

Limited influence of blunt aortic injuries on the outcome of polytraumatized patients: a matched pair analysis.

INTRODUCTION: Traumatic lesions of great vessels such as the aorta are life-threatening injuries. There is limited evidence about the influence of traumatic aortic injuries in multiple trauma patients in particular with regard to posttraumatic complications. The aim of this study was to evaluate the influence of blunt thoracic aortic injuries in multiple trauma patients compared to a multiple trauma cohort without this specific injury. In addition, the safety of Thoracic Endovascular Aortic Repair (TEVAR) in multiple trauma patients was analyzed. MATERIALS AND METHODS: A retrospective study was performed. We included all multiple trauma patients (ISS ≥ 16, age > 14 years) between 2005 and 2014 with (group BTAI) and without (group nBTAI) blunt traumatic aortic injuries who were treated at our level-1 trauma center. Demographic as well as clinical parameters were analyzed including injury pattern, mechanism of injury, posttraumatic complications such as ARDS, multiple organ dysfunction syndrome (MODS) and others. A matched pair analysis was performed by propensity score matching. RESULTS: In total, 721 patients were enrolled (group BTAI: n = 45; nBTAI: n = 676). In the initial study population, surgical intervention was done in n = 32 (71.1%) patients (TEVAR: n = 25; 78.1%), there was an increased AISChest and overall injury severity in group BTAI with associated significantly more posttraumatic complications in group BTAI. The matched pair analysis consisted of 42 patients per group. Beside an increased ventilation time, no significant differences were evident after the matching process. There was a trend to increased risk for SIRS using binary logistic regression analysis. CONCLUSIONS: Multiple trauma patients with blunt thoracic aortic injuries who are treated at a level-1 trauma center show a comparable outcome matched to their counterparts without aortic injuries. Our study confirms that using TEVAR in polytraumatized patients is a safe procedure. In all patients treated with TEVAR, there were no procedure-related complications, especially no neurological deficit.

Femoral malrotation after surgical treatment of femoral shaft fractures in children: a retrospective CT-based analysis.

BACKGROUND: Rotational malalignment is an important and not always avoidable complication after surgical treatment of femoral shaft fractures. The purpose of this study was to determine the incidence of rotational malalignment in children after surgical treatment of femoral shaft fractures and to identify potential patient- and treatment-related risk factors based on data obtained from CT scans. METHODS: We conducted a retrospective analysis of all patients aged less than 15 years with femoral shaft fractures admitted to our level 1 trauma centre between January 2004 and July 2014. Patients having obtained postoperative CT scans were included for the determination of rotational malalignment. A difference of greater than 15° in femoral torsion between both legs was considered as clinically relevant. Additionally, demographic data and clinical information such as fracture type, treatment method, fluoroscopy time and operating time were reviewed. RESULTS: A total of 24 patients were enrolled in this study. Clinically relevant femoral malrotation was identified in 10 patients (41.6%). Surgical revision was performed in 7 patients (29.2%). There was no association between the type of surgical procedure, age and the incidence and/or amount of femoral malrotation. CONCLUSIONS: The data suggest that relevant femoral malrotation is an evident problem after surgical treatment of femoral shaft fractures in children that requires critical postoperative assessment. LEVEL OF EVIDENCE: Level III, retrospective study.

Identification of potential biomarkers for post-traumatic complications released after trauma-hemorrhage from murine Kupffer cells and its investigation in lung and liver.

CONTEXT: Early diagnosis of complications after severe trauma by specific biomarkers remains difficult. OBJECTIVE: Identify potential new biomarkers for early diagnosis of post-traumatic complications. MATERIAL AND METHODS: Mice underwent pressure-controlled hemorrhage or sham procedure. Four hours later, genome-wide expression of isolated Kupffer cells was compared with controls using Affymetrix-Genechip-Expression-Analysis and real-time-PCR. RESULTS: Expression analysis and real-time-PCR revealed a significant increase of gene expression of Cxcl10, Il4ra, Csf2rb2, Lcn2, and Gbp5. CONCLUSION: Cxcl10, Il4ra, Csf2rb2, Lcn2, and Gbp5 might represent new biomarkers for early diagnosis of post-traumatic complications, if they are linked to the development of post-traumatic complications.

Simulator-Based Air Medical Training Program Christoph Life: From Concept to Course.

OBJECTIVE: Christoph Life is a simulator-based air medical training program and a new and innovative educational concept. Participants pass different scenarios with a fully equipped and movable helicopter simulator. Main focuses of the program are crew resource management (CRM) elements and team training. Information about expectations end effectiveness of the training is sparse. METHODS: During a 2-day training, participants learn CRM basics and complete various emergency medical scenarios. For evaluation, we used an anonymous questionnaire either with polar questions or a 6-coded psychometric Likert scale. The Wilcoxon test was used for statistical analysis. The significance level was set at P < .05. RESULTS: Thirteen teams of emergency physicians and specially trained paramedics underwent Christoph Life. It was evaluated largely positively and considered very helpful for daily work (5.7 ± 0.5) and avoiding mistakes (5.7 ± 0.5). The quality of participants' knowledge about CRM basics (3.5 ± 1.2 vs. 5.4 ± 0.7, P < .001), self-assessment of communication skills (4.2 ± 0.7 vs. 4.8 ± 0.8, P = .02), and active reflection of communication aspects (3.9 ± 0.9 vs. 5.5 ± 0.5, P < .001) could be strikingly increased. CONCLUSIONS: There is a considerable demand for intensified training on the part of the users. We were able to show that a simulator-based air medical training program is a helpful training tool with an obvious subjective benefit for the participants' nontechnical skills.

Beneficial effects of finasteride on hepatic and pulmonary immune response after trauma hemorrhage in mice.

UNLABELLED: The literature reveals evidence for a gender specific outcome after major trauma and hemorrhage. Increased levels of male sex hormones such as testosterone and even more dihydrotestosterone (DHT) mediate negative effects on the posttraumatic immune response. Pretreatment with finasteride several days before trauma hemorrhage (TH) led to improved outcomes in mice. We hypothesized that finasteride mediates its protective effects also when administered after TH within the resuscitation process. METHODS: Male C57BL/6N-mice underwent TH (blood pressure: 35 mmHg, 90 min) followed by finasteride application and fluid resuscitation. Plasma cytokines (MIP-1ß, TNF-α, MCP-1, MCP-3, IL-6), productive capacity of alveolar macrophages (AM) and hepatic Kupffer cells (KC) and systemic DHT levels were determined 4 h and 24 h thereafter. Pulmonary and hepatic infiltration of PMN was determined by immunohistochemical staining. RESULTS: Finasteride treatment resulted in reduced levels of systemic cytokines. This was accompanied by a reduced posttraumatic cytokine secretion of AM as well as Kupffer cells, thereby reducing hepatic distant organ damage as measured by reduced PMN infiltration. Systemic DHT levels were decreased following finasteride treatment. CONCLUSION: Finasteride exerts salutary effects on the pulmonary and hepatic immune response using a therapeutic approach following TH in mice. Therefore, finasteride might represent a potential agent following multiple trauma and hemorrhage.

Physical and psychological long-term outcome after traumatic brain injury in children and adult patients.

BACKGROUND: Several studies have indicated that younger age is associated with worse recovery after pediatric traumatic brain injury (TBI) compared to elder children. In order to verify this association between long-term outcome after moderate to severe TBI and patient's age, direct comparison between different pediatric age groups as well as an adult population was performed. METHODS: This investigation represents a retrospective cohort study at a level I trauma center including patients with moderate to severe, isolated TBI with a minimum follow-up of 10 years. According to their age at time of injury, patients were divided in pre-school (0-7 years), school (8-17 years) and adult (18-65 years) patients. Physical examination and standardized questionnaire on physical and psychological aspects (Glasgow Outcome Scale, Barthel Index, Impact of Event Scale, Hospital Anxiety and Depression Scale, short form 12) were performed. RESULTS: 135 traumatized patients were included. Physical and psychological long-term outcome was associated with injury severity but not with patients' age at time of injury. Outcome recovery measured by Glasgow Outcome Scale was demonstrated with best results for pre-school aged children (p = 0.009). According to the Hospital Anxiety and Depression Scale an increased incidence of anxiety (p = 0.010) and depression (p = 0.026) was evaluated in older patients. CONCLUSION: Long-term outcome perceptions after moderate to severe TBI presented in this study question current views of deteriorated recovery for the immature brain. The sustained TBI impact seemed not to reduce the child's ability to overcome the suffered impairment measured by questionnaire based psychological, physical and health related outcome scores. These results distinguish the relevance of rehabilitation and family support in the long term.

Survival benefit of helicopter emergency medical services compared to ground emergency medical services in traumatized patients.

INTRODUCTION: Physician-staffed helicopter emergency medical services (HEMS) are a well-established component of prehospital trauma care in Germany. Reduced rescue times and increased catchment area represent presumable specific advantages of HEMS. In contrast, the availability of HEMS is connected to a high financial burden and depends on the weather, day time and controlled visual flight rules. To date, clear evidence regarding the beneficial effects of HEMS in terms of improved clinical outcome has remained elusive. METHODS: Traumatized patients (Injury Severity Score; ISS≥9) primarily treated by HEMS or ground emergency medical services (GEMS) between 2007 and 2009 were analyzed using the TraumaRegister DGU® of the German Society for Trauma Surgery. Only patients treated in German level I and II trauma centers with complete data referring to the transportation mode were included. Complications during hospital treatment included sepsis and organ failure according to the criteria of the American College of Chest Physicians/Society of Critical Care Medicine (ACCP/SCCM) consensus conference committee and the Sequential Organ Failure Assessment (SOFA) score. RESULTS: A total of 13,220 patients with traumatic injuries were included in the present study. Of these, 62.3% (n=8,231) were transported by GEMS and 37.7% (n=4,989) by HEMS. Patients treated by HEMS were more seriously injured compared to GEMS (ISS 26.0 vs. 23.7, P<0.001) with more severe chest and abdominal injuries. The extent of medical treatment on-scene, which involved intubation, chest and treatment with vasopressors, was more extensive in HEMS (P<0.001) resulting in prolonged on-scene time (39.5 vs. 28.9 minutes, P<0.001). During their clinical course, HEMS patients more frequently developed multiple organ dysfunction syndrome (MODS) (HEMS: 33.4% vs. GEMS: 25.0%; P<0.001) and sepsis (HEMS: 8.9% vs. GEMS: 6.6%, P<0.001) resulting in an increased length of ICU treatment and in-hospital time (P<0.001). Multivariate logistic regression analysis found that after adjustment by 11 other variables the odds ratio for mortality in HEMS was 0.75 (95% CI: 0.636 to 862). CONCLUSIONS: Although HEMS patients were more seriously injured and had a significantly higher incidence of MODS and sepsis, these patients demonstrated a survival benefit compared to GEMS.

Impact of the body mass on complications and outcome in multiple trauma patients: what does the weight weigh?

Obesity is known as an independent risk factor for various morbidities. The influence of an increased body mass index (BMI) on morbidity and mortality in critically injured patients has been investigated with conflicting results. To verify the impact of weight disorders in multiple traumatized patients, 586 patients with an injury severity score >16 points treated at a level I trauma center between 2005 and 2011 were differentiated according to the BMI and analyzed regarding morbidity and outcome. Plasma levels of interleukin- (IL-) 6 and C-reactive protein (CRP) were measured during clinical course to evaluate the inflammatory response to the "double hit" of weight disorders and multiple trauma. In brief, obesity was the highest risk factor for development of a multiple organ dysfunction syndrome (MODS) (OR 4.209, 95%-CI 1.515-11.692) besides injury severity (OR 1.054, 95%-CI 1.020-1.089) and APACHE II score (OR 1.059, 95%-CI 1.001-1.121). In obese patients as compared to those with overweight, normal weight, and underweight, the highest levels of CRP were continuously present while increased systemic IL-6 levels were found until day 4. In conclusion, an altered posttraumatic inflammatory response in obese patients seems to determine the risk for multiple organ failure after severe trauma.

Comparison of different thoracic trauma scoring systems in regards to prediction of post-traumatic complications and outcome in blunt chest trauma.

BACKGROUND: As accurate assessment of thoracic injury severity in the early phase after trauma is difficult, we compared different thoracic trauma scores regarding their predictive ability for the development of post-traumatic complications and mortality. MATERIALS AND METHODS: Two hundred seventy-eight multiple trauma patients (ISS ≥ 16) age > 16 y with severe blunt chest trauma (AIS(chest) ≥ 3) admitted between 2000 and 2009 to Level I Trauma center were included. Exclusion criteria were severe traumatic brain injury (AIS(head) ≥ 3) and penetrating thoracic trauma. The association between AIS(chest), Pulmonary Contusion score (PCS), Wagner-score and Thoracic Trauma Severity score (TTS), and duration of ventilation, length of ICU stay, development of post-traumatic complications, and mortality was investigated. Statistical analysis was performed with χ(2)-test, ANOVA, logistic regression, and receiver operating characteristic (ROC) curve. RESULTS: Patients' mean age was 42.7 ± 17.0 y, the mean injury severity score was 28.7 ± 9.3 points. Overall, 60 patients (21.6%) developed ARDS, 143 patients (51.4%) SIRS, 110 patients (39.6%) sepsis, and 36 patients (13.0%) MODS. Twenty-two patients (7.9%) died. Among the examined thoracic trauma scores only the TTS was an independent predictor of mortality. With the TTS showing the best prediction power, the TTS, PCS, and Wagner-score were independent predictors of ventilation time, length of ICU stay, and the development of post-traumatic ARDS and MODS. CONCLUSIONS: Thoracic trauma scores combining anatomical and physiologic parameters like the TTS seem to be most suitable for severity assessment and prediction of outcome in multiple trauma patients with concomitant blunt chest trauma.

Tip apex distance, hip screw placement, and neck shaft angle as potential risk factors for cut-out failure of hip screws after surgical treatment of intertrochanteric fractures.

PURPOSE: To describe the quality of osteosynthesis after intertrochanteric fractures evaluation of tip apex distance (TAD) and position of the hip screw have been established. Furthermore, a slightly valgus fracture reduction has been suggested to reduce the risk of cut-out failure. However, uniform recommendations for optimal screw positioning and fracture reduction are still missing. The purpose of our study was to confirm potential risk factors for cut-out of hip screws of intertrochanteric fractures and to provide recommendations for practical clinical use. METHODS: A retrospective analysis of all patients with intertrochanteric fractures treated with a DHS or a gamma nail between January of 2007 and May of 2010 was performed at a level I trauma center. RESULTS: Two hundred thirty-five patients with intertrochanteric fractures after intra- and extramedullary stabilization were analyzed. A TAD of more than 25 mm was demonstrated to be the most important factor for cut-out in stable and unstable fractures. Fracture reduction with a valgus NSA of 5-10° was associated with a trend towards a lower rate of screw cut-out while an anterior placement of the screw (Parker's ratio index of <40) significantly increased cut-out incidence. CONCLUSIONS: According to our results, the TAD should not exceed 25 mm in stable (AO/OTA A1) as well as unstable (AO/OTA A2) fractures. An increased anterior hip screw placement should be avoided while fracture reduction with a slight valgus Neck Shaft seems favorable.

Intraoperative torsion control using the cortical step sign and diameter difference in tibial mid-shaft fractures.

AIM: Intramedullar nailing of tibial mid-shaft fractures is a common surgical treatment. Fracture reduction, however, remains challenging and maltorsion is a common discrepancy which aggravates functional impairment of gait and stability. The use of radiographic tools such as the cortical step sign (CSS) and the diameter difference sign (DDS) could improve fracture reduction. Therefore, the validity of the CSS and DDS was analyzed to facilitate detection of maltorsion in tibial mid-shaft fractures. METHODS: Tibial mid-shaft fractures were induced in human cadaveric tibiae according to the AO classification type A3. Torsional discrepancies from 0° to 30° in-/external direction were enforced after intramedullary nailing. Fluoroscopic-guided fracture reduction was assessed in two planes via analysis of the medical cortical thickness (MCT), lateral cortical thickness (LCT), tibial diameter (TD), anterior cortical thickness (ACT), posterior cortical thickness (PCT) and the transverse diameter (TD) of the proximal and distal fracture fragment. RESULTS: The TD, LCT and ACT have shown a highly significant correlation to predict tibial maltorsion. While a model combining ACT, LCT, PCT and TD lateral was most suitable model to identify tibial maltorsion, a torsional discrepancy of 15°was most reliably detected with use of the TD and ACT. CONCLUSION: The present study has shown, that maltorsion can be reliably assessed by the CSS and DDS during fluoroscopy. Thus, torsional discrepancies in tibial mid-shaft fractures can be most reliably assessed in the lateral plane by analysis of the LCT and TD.

3D osteotomies-improved accuracy with patient-specific instruments (PSI).

PURPOSE: Three-dimensional (3D) printed patient-specific instruments (PSI) have been introduced to increase precision and simplify surgical procedures. Initial results in femoral and tibial osteotomies are promising, but validation studies on 3D planning, manufacturing of patient-specific cutting blocks and 3D evaluation of the attained results are lacking. METHODS: In this study, patient-specific cutting blocks and spacers were designed, fabricated, and used to perform a high tibial osteotomy (HTO). After segmentation of CT data sets from 13 human tibiae, 3D digital planning of the HTO was performed with a medial opening of 8 mm. These 3D models were used to fabricate patient-specific cutting blocks and spacers. After the surgical procedure, accuracy was evaluated measuring 3D joint angles and surface deviations. RESULTS: The lowest mean deviation was found to be 0.57° (SD ± 0.27) for the MPTA. Medial and lateral tibial slope deviated from the 3D planning by an average of 0.98° (SD ± 0.53) and 1.26° (SD ± 0.79), respectively, while tibial torsion deviated by an average of 5.74° (SD ± 3.24). Color analysis of surface deviations showed excellent and good agreement in 7 tibiae. CONCLUSION: With 3D cutting blocks and spacers, the 3D planning of the HTO can be translated into reality with small deviations of the resulting joint angles. Within this study, the results of the individual steps are examined for errors and thus a critical evaluation of this new and promising method for performing patient-specific HTOs is presented.