[Patient-specific cutting guides in corrective osteotomy near to the knee joint]. / Patientenspezifische Schnittblöcke bei kniegelenknahen Korrekturosteotomien.

OBJECTIVE: Patient-specific cutting guides (PSCG) are used in osteotomy near to the knee joint to simplify the operative technique, shorten the duration of surgery, reduce radiation exposure and to exactly realize the preoperative planning during surgery, especially when complex deformities are corrected simultaneously in multiple planes. INDICATIONS: The application of PSCG is in principle possible in all osteotomies near to the knee joint but is especially useful in multidimensional, complex osteotomy. CONTRAINDICATIONS: No specific contraindications. SURGICAL TECHNIQUE: After multidimensional 3D analysis and planning using a preoperative computed tomography (CT) protocol, a 3D-printed patient-specific cutting guide is produced. This PSCG is used during standard osteotomy near to the knee. Using this PSCG the guided sawcut and predrilling of the screw positions inside the bone for the screws of the planned angle stable osteotomy plate are performed. The amount of the deformity correction needed is "stored" in the PSCG and is converted to the bony geometry during placement of the screws in the predrilled holes through the plate after opening or closing the osteotomy. Apart from that, the surgical approach and technique are equivalent to the standard osteotomy types near to the knee. POSTOPERATIVE MANAGEMENT: The application of PSCG in osteotomy near to the knee does not change the postoperative management of the specific osteotomy. RESULTS: The use of patient-specific cutting guides leads to a higher accuracy in the implementation of the preoperative planning and the desired target axis is achieved with greater accuracy. Multidimensional complex corrections can also be exactly planned and implemented. In addition, the intraoperative radiation exposure for the operation team can possibly be reduced.

Preventing Atrophic Long-Bone Nonunion: Retrospective Analysis at a Level I Trauma Center.

Background: Among the risk factors for nonunion are unchangeable patient factors such as the type of injury and comorbidities, and factors that can be influenced by the surgeon such as fracture treatment and the postoperative course. While there are numerous studies analyzing unchangeable factors, there is poor evidence for factors that can be affected by the physician. This raises the need to fill the existing knowledge gaps and lay the foundations for future prevention and in-depth treatment strategies. Therefore, the goal of this study was to illuminate knowledge about nonunion in general and uncover the possible reasons for their development; Methods: This was a retrospective analysis of 327 patients from 2015 to 2020 from a level I trauma center in Germany. Information about patient characteristics, comorbidities, alcohol and nicotine abuse, fracture classification, type of osteosynthesis, etc., was collected. Matched pair analysis was performed, and statistical testing performed specifically for atrophic long-bone nonunion; Results: The type of osteosynthesis significantly affected the development of nonunion, with plate osteosynthesis being a predictor for nonunion. The use of wire cerclage did not affect the development of nonunion, nor did the use of NSAIDs, smoking, alcohol, osteoporosis and BMI; Conclusion: Knowledge about predictors for nonunion and strategies to avoid them can benefit the medical care of patients, possibly preventing the development of nonunion.

Patient-Reported Outcomes following Tibial Plateau Fractures: Mid- to Short-Term Implications for Knee Function and Activity Level.

Background: Patients with complex proximal tibial plateau fractures (TPFs) tend to overestimate the prognosis of their injury, potentially due to factors such as a limited understanding, optimism, and the influence of the pain intensity. Understanding the reasons behind this misperception is crucial for healthcare providers to effectively communicate with patients and establish realistic expectations for treatment outcomes. The purpose of this study was to analyze the outcomes of TPFs, with a particular focus on patient-reported outcome measures concerning functional recovery, pain levels, and overall satisfaction with treatment. The authors aim to provide valuable insights into the realistic expectations and potential limitations that patients may encounter during their recovery journey. Methods: In this retrospective single-center study, all surgically treated TPFs between January 2014 and December 2019 with a minimum follow-up of 12 months were included. Several patient-reported outcome measures were obtained, including the International Knee documentation Committee Score (IKDC), Lyholm score, Tegner score, and visual analog scale (VAS) for pain. Fractures were classified according to Schatzker, and then subgrouped into simple (Schatzker I-III) and complex (Schatzker IV-VI) fractures. Results: A total of 54 patients (mean age 51.1 ± 11.9 years, 59.3% female) with a mean follow-up time of 3.9 years were included. Schatzker II fractures were present in 48% (n = 26) of the cases, with Schatzker III in 6% (n = 3), Schatzker IV fractures in 6% (n = 3), and Schatker VI fractures in 41% (n = 22) of the cases. All outcome scores showed a significant improvement between the first year after surgery and the last follow-up (mean: 3.9 years). Simple fractures showed significantly lower patient-reported outcomes when compared to the preinjury state; however, good to excellent results were observed. Patient-reported outcomes of complex fractures showed no significant changes in the study period with good to excellent results. When it comes to the Lysholm score, there were no significant differences in the outcome between simple and complex fractures. Furthermore, there was a return-to-sports rate of 100%, with high rates of changing sporting activity in 25% (simple fractures) and 45% in complex fractures. Conclusions: The data from this study showed that both simple and complex tibial plateau fractures show favorable outcomes at the midterm follow-up, and that injury severity does not correlate with worse results. While patients may tend to overestimate the recovery speed, this research highlights the importance of long-term follow-up, demonstrating a substantial improvement between one year post-surgery and the final evaluation. Return-to-sports rates were high, with adjustments needed for certain activities. However, patients should recognize the need to shift to lower-impact sports and the lengthy recovery process.

Tibial tuberosity-trochlear groove distance is significantly decreased by medial closing wedge distal femoral osteotomy.

PURPOSE: While medial closing wedge distal femoral osteotomy (MCWDFO) has been used to address patella instability combined with valgus malalignment, its impact on patellofemoral parameters remains uncharted. Hence, this study seeks to establish a three-dimensional (3D) planning of MCWDFO and measure its effect on the tibial tubercle - trochlear groove distance (TTTG) through simulation and calculation. METHODS: MCWDFO with a stepwise increment of one-degree varisation (1°-15°) was performed on 3D surface models of 14 lower extremities with valgus malalignment and 24 lower extremities with neutral alignment of the lower limb, resulting in a total of 608 simulations. Anatomic landmarks were employed to measure hip-knee-ankle angle (HKA), TTTG, and femoral torsion for each simulation. A mathematical formula was adopted to calculate TTTG changes following MCWDFO, and subsequently the mean simulated and calculated TTTG values were compared. Following a standardised protocol, MCWDFO was performed without rotational changes. RESULTS: MCWDFO exhibited an almost linear reduction in TTTG, at a rate of approximately -1.05 ± 0.13 mm per 1° of varisation, demonstrating a strong negative correlation (R = -0.83; p < 0.001). Limb alignment did not exert an influence on TTTG change; however, it correlated with tibial plateau width. The mean difference between the simulated and calculated TTTG values amounted to 0.03 ± 0.03 mm per 1° varisation (p < 0.001). CONCLUSION: The TTTG distance is linearly reduced by 1.05 mm for every 1° of varisation within the varus correction range of 0°-15° during MCWDFO. Patients with combined valgus and patellar instability may benefit from MCWDFO due to frequently pathological TTTG. LEVEL OF EVIDENCE: Level III, descriptive laboratory study.

[Possibilities and limits of intraoperative 2D imaging in trauma surgery]. / Möglichkeiten und Grenzen der intraoperativen 2D-Bildgebung in der Unfallchirurgie.

BACKGROUND: The two-dimensional (2D) imaging represents an essential and cost-effective component of intraoperative position control in fracture stabilization, even in the era of new three-dimensional (3D) imaging capabilities. OBJECTIVE: The aim of the present study, in addition to a current literature review, was to examine whether the intraoperative use of 2D images leads to a quality of fracture reduction comparable to postoperative computed tomographic (CT) analysis including 3D reconstructions. MATERIAL AND METHODS: A comparative retrospective analysis of intraoperative 2D and postoperative 3D image data was performed on 21 acetabular fractures stabilized via a pararectus approach according to an established protocol using the Matta criteria. RESULTS: The assessment of fracture reduction in intraoperative fluoroscopy compared with postoperative CT revealed a difference only in one case with respect to the categorization of the joint step reduction in the main loading zone. CONCLUSION: In the intraoperative use of 2D imaging for fracture treatment it is important to select the correct adjustment planes taking the anatomical conditions into account in order to achieve optimum assessability. In this way, the reduction result can be adequately displayed in fluoroscopy and is also comparable to the postoperative CT control. In addition, depending on the findings, optional intraoperative dynamic fluoroscopic assessment can have a direct influence on the further surgical procedure.

High Prevalence of Persistent Measurable Postoperative Knee Joint Laxity in Patients with Tibial Plateau Fractures Treated by Open Reduction and Internal Fixation (ORIF).

The development of post-traumatic osteoarthrosis after tibial plateau fracture (TPF) is multifactorial and can only be partially influenced by surgical treatment. There is no standardized method for assessing pre- and postoperative knee joint laxity. Data on the incidence of postoperative laxity after TPF are limited. The purpose of this study was to quantify postoperative laxity of the knee joint after TPF. Fifty-four patients (mean age 51 ± 11.9 years) were included in this study. There was a significant increase in anterior-posterior translation in 78.0% and internal rotation in 78.9% in the injured knee when compared to the healthy knee. Simple fractures showed no significant difference in laxity compared to complex fractures. When preoperative ligament damage and/or meniscal lesions were present and surgically treated by refixation and/or bracing, patients showed higher instability when compared to patients without preoperative ligament and/or meniscal damage. Patients with surgically treated TPF demonstrate measurable knee joint laxity at a minimum of 1 year postoperatively. Fracture types have no influence on postoperative laxity. This emphasizes the importance of recognizing TPF as a multifaceted injury involving both complex fractures and damage to multiple ligaments and soft tissue structures, which may require further surgical intervention after osteosynthesis.

Mismatch between Clinical-Functional and Radiological Outcome in Tibial Plateau Fractures: A Retrospective Study.

BACKGROUND: The evaluation of tibial plateau fractures (TPF) encompasses the assessment of clinical-functional and radiological parameters. In this study, the authors aimed to investigate the potential correlation between these parameters by utilizing both the clinical-functional and the modified radiological Rasmussen score. METHODS: In this retrospective monocentric study conducted at a level-I trauma center, patients who underwent surgery between January 2014 and December 2019 due to a TPF were included. The clinical-functional Rasmussen score prior to the injury, at 1-year postoperatively, and during the last follow-up (minimum 18 months) was assessed using a standardized questionnaire. Additionally, the modified radiological Rasmussen score was determined at the 1-year postoperative mark using conventional radiographs in two planes. RESULTS: A total of 50 patients were included in this study, comprising 40% (n = 20) men, and 60% (n = 30) women, with an average age of 47 ± 11.8 years (range 26-73 years old). Among them, 52% (n = 26) had simple fractures (classified according to Schatzker I-III), while 48% (n = 24; according to Schatzker IV-VI) had complex fractures. The mean follow-up was 3.9 ± 1.6 years (range 1.6-7.5 years). The functional Rasmussen score assessed before the injury and at follow-up showed an "excellent" average result. However, there was a significant difference in the values of complex fractures compared to before the injury. One year postoperatively, both the clinical-functional score and the modified radiological score demonstrated a "good" average result. The "excellent" category was more frequently observed in the functional score, while the "fair" category was more common in the radiological score. There was no agreement between the categories in both scores in 66% of the cases. CONCLUSIONS: The data from this retrospective study demonstrated that patients with TPF are able to achieve a nearly equivalent functional level in the medium-term after a prolonged recovery period, comparable to their pre-injury state. However, it is important to note that the correlation between clinical-functional and radiological parameters is limited. Consequently, in order to create prospective outcome scores, it becomes crucial to objectively assess the multifaceted nature of TPF injuries in more detail, both clinically and radiologically.

Early Internal Fixation of Concomitant Clavicle Fractures in Severe Thoracic Trauma Prevents Posttraumatic Pneumonia.

BACKGROUND: Severe thoracic trauma can lead to pulmonary restriction, loss of lung volume, and difficulty with ventilation. In recent years, there has been increasing evidence of better clinical outcomes following surgical stabilization of clavicle fractures in the setting of this combination of injuries. The aim of this study was to evaluate surgical versus non-surgical treatment of clavicle fractures in severe thoracic trauma in terms of clinical and radiological outcomes in order to make a generalized treatment recommendation based on the results of a large patient cohort. PATIENTS AND METHODS: This retrospective study included 181 patients (42 women, 139 men) from a European level I trauma centre with a median of 49.3 years in between 2005 and 2021. In 116 cases, the clavicle fracture was stabilized with locking plate or hook plate fixation (group 1), and in 65 cases, it was treated non-surgically (group 2). Long-term functional outcomes at least one year postoperatively using the disabilities of the arm, shoulder and hand (DASH) questionnaire and the Nottingham Clavicle Score (NCS) as well as radiological outcomes were collected in addition to parameters such as hospital days, intensive care days, and complication rates. RESULTS: The Injury Severity Score (ISS) was 17.8 ± 9.8 in group 1 and 19.9 ± 14.4 in group 2 (mean ± SEM; p = 0.93), the time in hospital was 21.5 ± 27.2 days in group 1 versus 16 ± 29.3 days in group 2 (p = 0.04). Forty-seven patients in group 1 and eleven patients in the group 2 were treated in the ICU. Regarding the duration of ventilation (group 1: 9.1 ± 8.9 days, group 2: 8.1 ± 7.7 days; p = 0.64), the functional outcome (DASH group 1: 11 ± 18 points, group 2: 13.7 ± 18. 4 points, p = 0.51; NCS group 1: 17.9 ± 8.1 points, group 2: 19.4 ± 10.3 points, p = 0.79) and the radiological results, no significant differences were found between the treatment groups. With an overall similar complication rate, pneumonia was found in 2% of patients in group 1 and in 14% of patients in group 2 (p = 0.001). DISCUSSION: This study could demonstrate that surgical locking plate fixation of clavicle fractures in combination with CWI significantly reducing the development of posttraumatic pneumonia in a large patient collection and, therefore, can be recommended as standard therapeutic approach for severe thoracic trauma.

Linear correlation between patellar positioning and rotation of the lower limb in radiographic imaging: a 3D simulation study.

PURPOSE: The purpose of this study was to quantify changes in rotation of the lower limb between image pairs based on patellar position. Additionally, we investigated the differences in alignment between centralized patellar and orthograde-positioned condyles. METHODS: Three-dimensional models of 30 paired legs were aligned in neutral position with condyles orthogonal to the sagittal axis and then rotated internally and externally in 1° increments up to 15°. For each rotation, the deviation of the patella and the subsequent changes in alignment parameters were calculated and plotted using a linear regression model. Differences between neutral position and patellar centralization were analysed qualitatively. RESULTS: A linear relationship between lower limb rotation and patellar position can be postulated. The regression model (R2 = 0.99) calculated a change of the patellar position of - 0.9 mm per degree rotation and alignment parameters showed small changes due to rotation. The physiological lateralization of the patella at neutral position was on average - 8.3 mm (SD: ± 5.4 mm). From neutral position, internal rotation that led to a centralized patella was on average - 9.8° (SD: ± 5.2°). CONCLUSION: The approximately linear dependence of the patellar position on rotation allows an inverse estimation of the rotation during image acquisition and its influence on the alignment parameters. As there is still no absolute consensus about lower limb positioning during image acquisition, data about the impact of a centralized patella compared to an orthograde condyle positioning on alignment parameters was provided. LEVEL OF EVIDENCE: IV.

Quality of long standing radiographs assessment of the patella position.

BACKGROUND: The gold standard for evaluating leg alignment is a long leg standing radiograph (LSR). The research states that a correct LSR should have a patella that is centered and facing forward as well as a fibula head superimposition (FHS) with a tibia that is 1/3 larger than the fibula. The purpose of this study was to determine levels of quality for LSR by quantifying and correlating the patella position and fibular head superimposition. METHOD: 741 lower limbs were included using two distinct measurement techniques, we calculated the patella position's (PD) departure from the center of the knee joint (M1 and M2). To measure the inter-rater dependability in assessing PD and FHS, intraclass correlation coefficients were determined. The Bland-Altman approach was used to compare M1 with M2's performance. We created three quality groups based on the average quantity of PD. RESULTS: The mean PD was 3.5 mm for M1 and 4.1 mm for M2, respectively. Three quality categories were created: group A for PD ≤ 5 mm, group B for PD 5-10 mm, and group C for PD of ≥10 mm. Group A takes up 70.9% of the LSR. Interestingly, group A's FHS was 21.3% than the typical value of 1/3. CONCLUSIONS: The patella's center should be centered within a 5 mm range and the fibular head should be 1/5 covered from the tibia. This study is the first to define quantitative metrics based on LSR analysis. LEVEL OF EVIDENCE: Level IV (diagnostic retrospective case series).

Preoperative Mixed-Reality Visualization of Complex Tibial Plateau Fractures and Its Benefit Compared to CT and 3D Printing.

BACKGROUND: Various studies have shown the benefit of three-dimensional (3D) computed tomography (CT) reconstruction and especially 3D printing in the treatment of tibial plateau fractures (TPFs). This study aimed to investigate whether mixed-reality visualization (MRV) using mixed-reality glasses can provide a benefit for CT and/or 3D printing in planning treatment strategies for complex TPFs. METHODS: Three complex TPFs were selected for the study and processed for 3D imaging. Subsequently, the fractures were presented to specialists in trauma surgery using CT (including 3D CT reconstruction), MRV (hardware: Microsoft HoloLens 2; software: mediCAD MIXED REALITY) and 3D prints. A standardized questionnaire on fracture morphology and treatment strategy was completed after each imaging session. RESULTS: 23 surgeons from 7 hospitals were interviewed. A total of 69.6% (n = 16) of those had treated at least 50 TPFs. A change in fracture classification according to Schatzker was recorded in 7.1% of the cases and in 78.6% an adjustment of the ten-segment classification was observed after MRV. In addition, the intended patient positioning changed in 16.1% of the cases, the surgical approach in 33.9% and osteosynthesis in 39.3%. A total of 82.1% of the participants rated MRV as beneficial compared to CT regarding fracture morphology and treatment planning. An additional benefit of 3D printing was reported in 57.1% of the cases (five-point Likert scale). CONCLUSIONS: Preoperative MRV of complex TPFs leads to improved fracture understanding, better treatment strategies and a higher detection rate of fractures in posterior segments, and it thus has the potential to improve patient care and outcomes.

Computer-assisted simulated workplace-based assessment in surgery: application of the universal framework of intraoperative performance within a mixed-reality simulation.

Objectives: Workplace-based assessment (WBA) is a key requirement of competency-based medical education in postgraduate surgical education. Although simulated workplace-based assessment (SWBA) has been proposed to complement WBA, it is insufficiently adopted in surgical education. In particular, approaches to criterion-referenced and automated assessment of intraoperative surgical competency in contextualized SWBA settings are missing.Main objectives were (1) application of the universal framework of intraoperative performance and exemplary adaptation to spine surgery (vertebroplasty); (2) development of computer-assisted assessment based on criterion-referenced metrics; and (3) implementation in contextualized, team-based operating room (OR) simulation, and evaluation of validity. Design: Multistage development and assessment study: (1) expert-based definition of performance indicators based on framework's performance domains; (2) development of respective assessment metrics based on preoperative planning and intraoperative performance data; (3) implementation in mixed-reality OR simulation and assessment of surgeons operating in a confederate team. Statistical analyses included internal consistency and interdomain associations, correlations with experience, and technical and non-technical performances. Setting: Surgical simulation center. Full surgical team set-up within mixed-reality OR simulation. Participants: Eleven surgeons were recruited from two teaching hospitals. Eligibility criteria included surgical specialists in orthopedic, trauma, or neurosurgery with prior VP or kyphoplasty experience. Main outcome measures: Computer-assisted assessment of surgeons' intraoperative performance. Results: Performance scores were associated with surgeons' experience, observational assessment (Objective Structured Assessment of Technical Skill) scores and overall pass/fail ratings. Results provide strong evidence for validity of our computer-assisted SWBA approach. Diverse indicators of surgeons' technical and non-technical performances could be quantified and captured. Conclusions: This study is the first to investigate computer-assisted assessment based on a competency framework in authentic, contextualized team-based OR simulation. Our approach discriminates surgical competency across the domains of intraoperative performance. It advances previous automated assessment based on the use of current surgical simulators in decontextualized settings. Our findings inform future use of computer-assisted multidomain competency assessments of surgeons using SWBA approaches.

[Influence of the COVID-19 pandemic on fracture epidemiology exemplified by tibial plateau fractures]. / Einfluss der COVID-19-Pandemie auf die Frakturepidemiologie am Beispiel der Tibiaplateaufraktur.

BACKGROUND: During the COVID-19 pandemic interventions, such as contact restrictions, lockdowns and postponement of elective surgeries were taken to ease the burden on the healthcare system. Among the population, these interventions led to changes in recreational behavior as well as personal transportation. OBJECTIVE: This paper examines the epidemiological data of tibial plateau fractures (TPF) before and during the pandemic and to what extent pandemic control measures had an impact. MATERIAL AND METHODS: In this retrospective monocentric study of a German level 1 trauma center, the intra-articular tibial plateau fractures of the years 2019 and 2020 were compared regarding incidence, demographics, cause of the accident, and treatment strategy. Fracture classification was according to Schatzker, AO/OTA, and Moore. RESULTS: Incidence showed a decrease of -8.5% as well as a shift in the age incidence curves. There was a decrease in incidence during lockdown periods but also an increase in late summer 2020 compared to 2019. Tripping accidents (+12.4%) and bicycle accidents (+6.6%) increased in the pandemic year, whereas motorized traffic accidents (-7%) and skiing accidents (-10%) decreased. In terms of fracture morphology, 2020 showed an increase in impression fractures and a decrease in complex fractures. The number of surgically treated patients decreased by 7.3%. CONCLUSION: The 12 months of pandemic resulted in only a slight incidence decrease of intra-articular tibial plateau fractures. The pandemic control measures showed effects within the calendar year and led directly and indirectly to a change in incidence, cause of the accident, fracture entities and care strategy.

Changing patterns in the epidemiology of tibial plateau fractures: a 10-year review at a level-I trauma center.

PURPOSE: Mobility patterns of western societies have been changing due to ongoing demographic change. Therefore, continuously updated epidemiological data on fracture morphology and treatment strategies are needed. METHODS: This retrospective single-center study included all tibial plateau fractures (TPF) between January 2011 and December 2020 in a level-I trauma center in Central Europe. Epidemiology, trauma mechanism and fracture morphology were analyzed. Age- and sex-specific differences regarding fracture classification (Schatzker, AO/OTA, Moore) and changes during the study period are highlighted. RESULTS: A total of 607 patients (55.2% women, 44.8% men, mean age 52.9 years (± 17.9)) were included in the study, 462 (76.1%) thereof having undergone surgical treatment. Over the decade, an increase in mean age (+ 7.4 years; p = 0.10), incidence (+ 68%; p < 0.05) and low-energy trauma was observed, with the highest peak in elderly women. Within classifications, AO/OTA 41-B3 (24.9%), Schatzker II (26.8%) and Moore V (46.6%) fractures were the most common. CONCLUSION: Incidence (+ 68%), mean age and fractures with signs of knee dislocation of tibial plateau fracture increased over the last decade and low-energy trauma mechanism are more frequent. As the increase in incidence is mainly seen in older women, the comorbidities and need for immediate postoperative full weight-bearing have to be considered in treatment strategies.

High rate of complications after corrective midfoot/subtalar arthrodesis and Achilles tendon lengthening in Charcot arthropathy type Sanders 2 and 3.

PURPOSE: Corrective midfoot resection arthrodesis is the standard treatment of Charcot arthropathy type Sanders 2 and 3 with severe dislocation. In order to critically evaluate the effect of surgical correction, a retrospective analysis of our patient cohort was performed. Hereby, special emphasis was set on the analysis of the pre- and post-operative equinus position of the hindfoot. METHODS: Retrospectively, all patients (n = 82) after midfoot resection arthrodesis in Charcot type Sanders 2 or 3 were included. Complications were recorded, and the mean complication-free interval was calculated. Additionally, the calcaneal pitch as well as Meary's angle were measured pre- and post-operatively and in case of complications. RESULTS: Overall complication rate was 89%. Revision surgery was necessary in 46% of all patients. The mean complication-free interval was 285 days (0-1560 days). Calcaneal pitch and Meary's angle significantly improved after operation but returned to pre-operative values after onset of complications. Achilles tendon lengthening showed no significant effects on the mean complication-free interval. CONCLUSION: Operative treatment of Charcot arthropathy remains a surgical challenge with high complication rates. Surgical correction of equinus position has been highlighted for successful treatment but was not able to prevent complications in this study, which is demonstrated by the recurrent decrease of the calcaneal pitch in cases of reoperation. Therefore, as a conclusion of our results, our treatment algorithm changed towards primarily addressing the equinus malpositioning of the hindfoot by corrective arthrodesis of the hindfoot.

Intraoperative alignment correlates well with long standing radiographs - The X-ray grid method in complex knee surgery.

OBJECTIVE: While long standing radiographs (LSR) represent the gold standard for preoperative alignment assessment and planning of lower limb deformity corrections, there is no consensus about the intraoperative alignment assesments (IAC) due to various limitations of the common methods. The present study introduces a radiolucent X-ray grid with integrated radiopaque lines explicitly designed for fluoroscopic IAC and evaluates its reliability in comparsion to the LSR. METHODS: Patients with posttaumatic and congenital lower limb deformity surgery and preoperative LSR as well as fluoroscopic IAC utilizing the X-ray grid were retrospectively included to the study. The mechanical axis deviation (MAD) in percentage of the maximum tibial width from the medial to the lateral in comparison between the image pairs was set as primary outcome parameter. Multiple rater and measurements determined intra- and interobserver reliabilit of both imaging methods. In addition, the effects of age, gender, body mass index (BMI), etiology, joint line convergence angle (JLCA), and extent varus or valgus deformity were analysed. RESULTS: A total of 84 patients were finally included. The mean absolute difference of MAD between the two techniques was 7.2 ± 0.8%. MAD between the LSR and IAC correlated at a high level (R = 0.96, p <0.001). The agreement decreased with increasing extent of deformity (p <0.01) and with higher deviation of JLCA between LSR and IAC (p <0.01). Intra- and interobserver concordance correlation coefficient (CCC) for MAD measurements were 0.99 for both imaging techniques. CONCLUSION: Fluoroscopy combined with the X-ray grid method is a valid tool for intraoperative assessment of lower limb alignment in deformity correction surgery, and the correlation between LSR and IAC is better than in other similar techniques described in the literature. However, in case of severe coronal alignment deformity and highly divergent JLCA, the agreement between both imaging techniques decreases significantly.

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.

Reliability of 3D planning and simulations of medial open wedge high tibial osteotomies.

Purpose: In medial open-wedge high tibial osteotomy (HTO) hinge axis and osteotomy plane influence the resulting anatomy, but accurate angular quantifications using 3D-planning-simulations are lacking. The objectives of this study were developing a standardized and validated 3D-planning method of an HTO and to perform several simulated realignments to explain unintended anatomy changes. Methods: The cutting direction of the main osteotomy was defined parallel to the medial tibial slope and the hinge axis 1.5 cm distal to the lateral plateau. For interobserver testing, this 3D planning was performed on 13 digital models of human tibiae by two observers. In addition, four different hinge axis positions and five differently inclined osteotomy planes each were simulated. The osteotomy direction ranged from medial 0°-30° anteromedial, while the tilt of the osteotomy plane compared to the tibial plateau was -10° to +10°. All anatomic angular changes were calculated using 3D analysis. Results: Multiple HTO plannings by two medical investigators using standardized procedures showed only minimal differences. In the 3D-simulation, each 10° rotation of the hinge axis resulted in a 1.7° significant increase in slope. Tilting the osteotomy plane by 10° resulted in significant torsional changes of 2°, in addition to minor but significant changes in the medial proximal tibial angle (MPTA). Conclusion: Standardized 3D-planning of the HTO can be performed with high reliability using two-observer planning. 3D-simulations suggest that control of the osteotomy plane is highly relevant to avoid unintended changes in the resulting anatomy, but this can be a helpful tool to modify specific angles in different pathologies in the HTO.

[Prophylactic fasciotomy in tibial osteotomies: functional results]. / Prophylaktische Fasziotomie bei Tibia-Osteotomien: funktionelle Ergebnisse.

BACKGROUND: Intramedullary nailing in tibial osteotomy (TO) can be combined with minimally invasive prophylactic fasciotomy (PF) of the anterior compartment of the lower leg to prevent postoperative acute compartment syndrome (CS). So far no studies are available on the effects of TO or PF on specific functions of the extensor muscles. OBJECTIVE: To investigate the medium-term outcome after PF in TO in patients without preoperative functional impairment. MATERIAL AND METHODS: In 41 cases (28 women, 13 men) the patients were questioned with respect to clinical function on average 6.1 years after elective TO and PF fixed with intramedullary nails. Of the cases 23 were examined measuring isometric strength and range of motion (ROM) of dorsiflexion (DF) of the foot. Strength was compared to the 10% standard percentile to test for clinical relevance and to the contralateral side if applicable. RESULTS: In an average of 86% of the cases no or minor functional impairment of the extensors was reported. The DF of the foot was rated as the leading impairment. Mean strength did not differ significantly from the gender-specific 10% standard percentiles but was significantly lower on the operated side with 16.0 ± 6.5 kgf compared to the healthy side with 17.5 ± 6.3 kgf (p < 0.01). Subjective impairments of DF of the foot correlated clearly negatively with ROM (rs = -0.46, p < 0.05) but not with strength. CONCLUSION: The results indicate a low occurrence of subjectively relevant functional impairment of the extensor muscles. The decrease of strength was not found to be clinically relevant. Subjective impairments appeared to be caused by a decrease of ROM, not strength.