There are a number of classification systems for intracapsular fractures of the proximal femur, but none has been shown to be practical with satisfactory reproducibility and accurate predictive value. We have investigated the AO classification and evaluated intra-and interobserver accuracy and its value in predicting treatment and outcome. We found it to have very poor intra- and interobserver reliability and to be of limited predictive use for the outcome of treatment. A simplified system in which the subdivisions were allocated to one of three groups of undisplaced, displaced and basal fractures was found to be of value. We conclude that this is the only division which is appropriate for these fractures and that the AO system for intracapsular fractures is too complicated and should not be used

Interobserver reliability of the AO system of classification of fractures of the distal radius was assessed using plain radiographs and CT. Five observers classified 30 Colles’-type fractures using only plain radiographs; two months later they were reclassified using CT in addition.

Interobserver reliability was poor in both series when detailed classification was used. By reducing the categories to five, interobserver reliability was slightly improved, but was still poor. When only two AO types were used, the reliability was moderate using plain radiographs and good to excellent with the addition of CT.

The use of CT as well as plain radiographs brings interobserver reliability to a good level in assessment of the presence or absence of articular involvement, but is otherwise of minor value in improving the interobserver reliability of the AO system of classification of fractures of the distal radius.

Trochanteric femur fractures can be classified using the Jensen modification of the Evans’ classification or the AO/ASIF classification. This study compares the reproducibility of both classifications. Furthermore we evaluated the agreement on fracture stability, choice of osteosynthesis, fracture reduction and the accuracy of implant positioning. We used pre- and postoperative lateral and AP radiographs of 50 trochanteric femur fractures. The fractures were classified using both classifications with a three-month interval by five trauma surgeons and five residents. Inter-, and intra-observer variability was analysed using the multi-rater Fleiss’ kappa and the Cohen’ kappa tests. The AO/ASIF classification showed a kappa coefficient for the intra-observer agreement of 0.40 (SE 0.01). After leaving out classification-subgroups, AO/ASIF classification showed a coefficient of 0.68 (SE 0.02) and the Jensen classification a coefficient of 0.48 (SE 0.02). The kappa values of the intra-observer reliability of the AO/ASIF classification with and without subgroups were: 0.43 (SE 0.08) and 0.71 (SE 0.08) respectively. For the Jensen classification the kappa value was 0.56 (SE 0.09). Preoperative agreement on fracture stability and type of implant to be chosen showed kappa values of 0.39 (SE 0.05) and 0.65 (SE 0.04). Postoperative disagreement on the choice of implant was 15% (kappa 0.17, SE 0.08). Kappa values for postoperative fracture reduction and position of the implant were 0.29 (SE 0.09) and 0.22 (SE 0.05), respectively. Both the Jensen classification and the AO/ASIF classification showed poor reproducibility. However, without subgroups the AO/ASIF classification seemed more reliable. This study suggests that the definition of stability of trochanteric fractures remains controversial, which possibly complicates the choice of osteosynthesis. Refinement of the classifications or renewed definition of trochanteric fractures seems to be required

Background. Current literature of definition, classification and outcomes of fractures of talar body remains controversial. Our primary purpose is to present an unusual combination of fractures of talar body with pantalar involvement / dislocation / extension as a basis for modification of Müller AO / OTA Classification. Methods. We include four consecutive patients, who sustained talar body fractures with pantalar subluxation/dislocation /extension. These unusual injury patterns lead us to reconsider Müller AO / OTA Classification in the light of another widely used talar fracture classification, Hawkins Classification of fractures of neck of talus and subsequent modification by Canale and Kelly. Results. Müller AO / OTA Classification comprises CI – Ankle joint involvement, C2 – Subtalar joint involvement, C3 – Ankle and subtalar joint involvement. We propose Modification of Müller AO / OTA. Classification. C1 – Absolutely undisplaced fracture; C2 – Ankle and Subtalar joint involvement: subluxation; C3 – Ankle and subtalar joint involvement: subluxation with comminution; C4 – Ankle, subtalar and talonavicular joint involvement. Conclusions. Our modification redefines Müller AO / OTA Classification, extends and fills the void in the classification by inclusion of C4, draws attention to stability of talonavicular joint and reflects increasing severity of injury in fractures of talar body

We sought to quantify agreement by different assessors of the AO classification for distal fractures of the radius. Thirty radiographs of acute distal radial fractures were evaluated by 36 assessors of varying clinical experience. Our findings suggest that AO ‘type’ and the presence or absence of articular displacement are measured with high consistency when classification of distal radial fractures is undertaken by experienced observers. Assessors at all experience levels had difficulty agreeing on AO ‘group’ and especially AO ‘subgroup’. To categorise distal radial fractures according to joint displacement and AO type is simple and reproducible. Our study examined only whether distal radial fractures could be consistently classified according to the AO system. Validation of the classification as a predictor of outcome will require a prospective clinical study

We conducted an observational radiographic study to determine the inter- and intra-observer reliability of the AO classification of fractures of the distal radius. Plain posteroanterior and lateral radiographs of 456 patients with an acute fracture of the distal radius were classified by a consultant orthopaedic hand specialist and two specialist trainees, and the k coefficient for the inter- and intra-observer reliability of the type, group and subgroup classification was calculated.

Only the type of fracture (A, B or C) was found to provide substantial intra-observer reliability (k _type 0.65). The inclusion of ‘group’ and ‘subgroup’ into the classification reduced the inter-observer reliability to fair (k_group 0.29, k_subgroup = 0.28) and the intra-observer reliability to moderate (k_group 0.53, k_subgroup 0.49). Disagreement was found to arise between specific subgroups, which may be amenable to clarification.

Cite this article: Bone Joint J 2015; 97-B:818–23.

Aims. Low-energy distal radius fractures (DRFs) are the most common upper arm fractures correlated with bone fragility. Vitamin D deficiency is an important risk factor associated with DRFs. However, the relationship between DRF severity and vitamin D deficiency is not elucidated. Therefore, this study aimed to identify the correlation between DRF severity and serum 25-hydroxyvitamin-D level, which is an indicator of vitamin D deficiency. Methods. This multicentre retrospective observational study enrolled 122 female patients aged over 45 years with DRFs with extension deformity. DRF severity was assessed by three independent examiners using 3D CT. Moreover, it was categorized based on the AO classification, and the degree of articular and volar cortex comminution was evaluated. Articular comminution was defined as an articular fragment involving three or more fragments, and volar cortex comminution as a fracture in the volar cortex of the distal fragment. Serum 25-hydroxyvitamin-D level, bone metabolic markers, and bone mineral density (BMD) at the lumbar spine, hip, and wrist were evaluated six months after injury. According to DRF severity, serum 25-hydroxyvitamin-D level, parameters correlated with bone metabolism, and BMD was compared. Results. The articular comminuted group (n = 28) had a significantly lower median serum 25-hydroxyvitamin-D level than the non-comminuted group (n = 94; 13.4 ng/ml (interquartile range (IQR) 9.8 to 17.3) vs 16.2 ng/ml (IQR 12.5 to 20.4); p = 0.005). The AO classification and volar cortex comminution were not correlated with the serum 25-hydroxyvitamin-D level. Bone metabolic markers and BMD did not significantly differ in terms of DRF severities. Conclusion. Articular comminuted DRF, referred to as AO C3 fracture, is significantly associated with low serum 25-hydroxyvitamin-D levels. Therefore, vitamin D. 3. supplementation for vitamin D deficiency might prevent articular comminuted DRFs. Nevertheless, further studies must be conducted to validate the results of the current study. Cite this article: Bone Jt Open 2022;3(3):261–267

The June 2023 Trauma Roundup. 360. looks at: Aspirin or low-molecular-weight heparin for thromboprophylaxis?; Lateral plating or retrograde nailing for distal femur fractures?; Sciatic nerve palsy after acetabular fixation: what about patient position?; How reliable is the new OTA/AO classification for trochanteric hip fractures?; Young hip fractures: is a medial buttress the answer?; When is the best time to ‘flap’ an open fracture?; The mortality burden of nonoperatively managed hip fractures

The December 2023 Trauma Roundup. 360. looks at: Distal femoral arthroplasty: medical risks under the spotlight; Quads repair: tunnels or anchors?; Complex trade-offs in treating severe tibial fractures: limb salvage versus primary amputation; Middle-sized posterior malleolus fractures – to fix?; Bone transport through induced membrane: a randomized controlled trial; Displaced geriatric femoral neck fractures; Risk factors for reoperation to promote union in 1,111 distal femur fractures; New versus old – reliability of the OTA/AO classification for trochanteric hip fractures; Risk factors for fracture-related infection after ankle fracture surgery

Aims. We aimed to evaluate the health-related quality of life (HRQoL) in children with supracondylar humeral fractures (SCHFs), who were treated following the recommendations of the Paediatric Comprehensive AO Classification, and to assess if HRQoL was associated with AO fracture classification, or fixation with a lateral external fixator compared with closed reduction and percutaneous pinning (CRPP). Methods. We were able to follow-up on 775 patients (395 girls, 380 boys) who sustained a SCHF from 2004 to 2017. Patients completed questionnaires including the Quick Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH; primary outcome), and the Pediatric Quality of Life Inventory (PedsQL). Results. An AO type I SCHF was most frequent (327 children; type II: 143; type III: 150; type IV: 155 children). All children with type I fractures were treated nonoperatively. Two children with a type II fracture, 136 with a type III fracture, and 141 children with a type IV fracture underwent CRPP. In the remaining 27 children with type III or IV fractures, a lateral external fixator was necessary for closed reduction. There were no open reductions. After a mean follow-up of 6.3 years (SD 3.7), patients with a type I fracture had a mean QuickDASH of 2.0 (SD 5.2), at a scale of 0 to 100, with lower values representing better HRQoL (type II: 2.8 (SD 10.7); type III: 3.3 (SD 8.0); type IV: 1.8 (SD 4.6)). The mean function score of the PedsQL ranged from 97.4 (SD 8.0) for type I to 96.1 (SD 9.1) for type III fractures, at a scale of 0 to 100, with higher values representing better HRQoL. Conclusion. In this cohort of 775 patients in whom nonoperative treatment was chosen for AO type I and II fractures and CRPP or a lateral external fixator was used in AO type III and IV fractures, there was equally excellent mid- and long-term HRQoL when assessed by the QuickDASH and PedsQL. These results indicate that the treatment protocol followed in this study is unambiguous, avoids open reductions, and is associated with excellent treatment outcomes. Cite this article: Bone Joint J 2020;102-B(6):755–765

Distal radius fractures (DRF) are the most common fracture type in all age groups combined. Unstable DRF may be surgically managed with volar or dorsal plate fixation. Dorsal plating has traditionally been associated with decreased range of motion (ROM). However, this assumption has not been recently assessed to determine whether functional ROM is achievable (approximately 54o of flexion and 60o of extension) with recent advances in lower profile dorsal plate design. The aim of this study was therefore to compare ROM and patient reported outcome measures between volar and dorsal plating methods for DRF. A meta-analysis was performed to directly compare ROM and DASH scores between dorsal and volar plate fixation for DRF. Separate literature searches for each plating method were performed using MedLine and EMBase on January 28, 2018. Exclusion criteria consisted of non-English articles, basic science articles, animal/cadaver studies, case studies/series, combined operative approaches, papers published more than 20 years ago and paediatric studies. Only articles with at least one year patient follow-up and a) ROM and AO distal radius fracture classification, or b) DASH scores were included. Raw data was extracted from all articles that met inclusion criteria to compile a comprehensive dataset for analysis. Descriptive statistics with z-score comparison for AO classification or a two-tailed independent samples t-test for ROM and DASH scores for dorsal versus volar plating were performed. Significance was defined as p < 0 .05. After rigorous screening, 6 dorsal plating and 43 volar plating articles met inclusion criteria for ROM/AO classification versus 6 dorsal plating and 44 volar plating articles for DASH scores. The weighted means of flexion (dorsal 54.9o, SD 9.3, n=257, volar 61.3o, SD 11.5, n=1906) and extension (dorsal 60.0o, SD 12, n=257, volar 62.8o, SD 11.4, n=1906) were statistically significantly different (both p < 0 .001) between the two plating methods. The volar plating group had a significantly higher proportion of AO type C fractures (dorsal 0.5, n =169, volar 0.6, n=1246, p < 0 .001). The weighted means of reported DASH scores were not significantly different between dorsal (14.01, SD 14.8) versus volar (13.6, SD 12.8) plating (p=0.54). Though mean wrist flexion and extension were statistically different between the dorsal versus volar plating methods, the difference between group means was less than 5o, which is unlikely to be clinically significant. Additionally, we did not find a significant difference in DASH scores between the two plating methods. Taken together, these findings imply that the statistical difference in ROM outcomes are likely not clinically significant and should therefore not dictate choice of plating method for fixation of DRF

With an aging population and increase in total knee arthroplasty, periprosthetic distal femur fractures (PDFFs) have increased. The differences between these fractures and native distal femur fractures (NDFF) have not been comprehensively investigated. The purpose of this study was to compare the demographic, fracture, and treatment details of PDFFs compared to NDFFs. A retrospective study of patients ≥ 18 years old who underwent surgical treatment for either a NDFF or a PDFF from 2010 to 2020 at a level 1 trauma center was performed. Demographics, AO/OTA fracture classification, quality of reduction, fixation constructs, and unplanned revision reoperation were compared between PDFF patients and NDFF patients using t-test and Fisher's exact test. 209 patients were identified with 70 patients having a PDFF and 139 patients having a NDFF. Of note, 48% of NDFF had a concomitant fracture of the ipsilateral knee (14%) or tibial plateau (15%). The most common AO/OTA classification for PDFFs was 33A3.3 (71%). NDFFs had two main AO/OTA classifications of 33C2.2 (28%) or 33A3.2. (25%). When controlling for patient age, bone quality, fracture classification, and fixation, the PDFF group had increased revision reoperation rate compared to NDFF (P < 0.05). PDFFs tend to occur in elderly patients with low bone quality, have complete metaphyseal comminution, and be isolated; whereas, NDFF tend to occur in younger patients, have less metaphyseal comminution, and be associated with other fractures. When controlling for variables, PDFF are at increased risk of unplanned revision reoperation. Surgeons should be aware of these increased risks in PDFFs and future research should focus on these unique fracture characteristics to improve outcomes

Introduction. Non-union is debilitating, costly and affects 2–8% of intramedullary fixed fractures. Clinical data suggest that percutaneous interfragmentary screws offer a less invasive alternative to exchange nailing. This study aimed to assess their efficiency with biomechanical analyses. Materials and Methods. A tibia was prepared for finite element analysis by creating a fracture of AO classification 42A2b, prior to reaming and insertion of an intramedullary nail. A callus was modelled as granulation tissue and gait loads were applied. The model was validated against published data and with sensitivity studies. The effects of weightbearing, fracture gap and angle, percutaneous screws and exchange nailing were compared through quantification of interfragmentary motion and strain, with the latter used to gauge healing performance via mechano-regulation theory. Results. Axial interfragmentary motion increased with increasing weightbearing, however, shear decreased at 25–50% weightbearing, leading to superior healing performance. Fracture gap had minimal effect on axial motion, but larger gaps gave greater shear, compromising healing. Elevated fracture obliquity culminated in more shear and inferior healing. Exchange nailing reduced axial motion by ∼30%, but had little effect on shear. Conversely, percutaneous screws had negligible effect on axial motion, but reduced shear by ∼15%, with three screws having a similar net effect on healing as exchange nailing from 10 to 11mm. Conclusions. This study provides new insight into fracture healing biomechanics and discovered that partial weightbearing, less oblique fractures and percutaneous screws all reduce shear, enhancing healing

Introduction. Diaphyseal tibial fractures account for approximately 1.9% of adult fractures. Several studies demonstrate a high proportion of diaphyseal tibial fractures have ipsilateral occult posterior malleolus fractures, this ranges from 22–92.3%. Materials and Methods. A retrospective review of a prospectively collected database was performed at Liverpool University Hospitals NHS Foundation Trust between 1/1/2013 and 9/11/2020. The inclusion criteria were patients over 16, with a diaphyseal tibial fracture and who underwent a CT. The articular fracture extension was categorised into either posterior malleolar (PM) or other fracture. Results. 764 fractures were analysed, 300 had a CT. There were 127 intra-articular fractures. 83 (65.4%) cases were PM and 44 were other fractures. On univariate analysis for PM fractures, fibular spiral (p=.016) fractures, no fibular fracture(p=.003), lateral direction of the tibial fracture (p=.04), female gender (p=.002), AO 42B1 (p=.033) and an increasing angle of tibial fracture. On multivariate regression analysis a high angle of tibia fracture was significant. Other fracture extensions were associated with no fibular fracture (p=.002), medial direction of tibia fracture (p=.004), female gender (p=.000), and AO 42A1 (p=.004), 42A2 (p=.029), 42B3 (p=.035) and 42C2 (p=.032). On multivariate analysis, the lateral direction of tibia fracture, and AO classification 42A1 and 42A2 were significant. Conclusions. Articular extension happened in 42.3%. A number of factors were associated with the extension, however multivariate analysis did not create a suitable prediction model. Nevertheless, rotational tibia fractures with a high angle of fracture should have further investigation with a CT

Introduction and Objective. When using radiation intraoperatively, a surgeon should aim to maintain the dose as low as reasonably achievable to obtain the diagnostic or therapeutic goal. The UK Health Protection Agency reported mean radiation dose-area-product (DAP) of 4 Gy cm2 for hip procedures. We aimed to investigate factors associated with increased radiation exposure in fixation of proximal femur fractures. Materials and Methods. We assessed 369 neck of femur fractures between April 2019 and April 2020 in one district general hospital. Fractures were classified as extracapsular or intracapsular and into subtypes as per AO classification. Data was collected on type of fractures, implants used, level of surgeon, duration of surgery and DAP. Types of fractures were subclassified as complex (multifragmentary, subtrochanteric and reverse oblique) or simple. Results. Patients with fractures fixed with DHS, short PFNA, long PFNA and cannulated screws were included. 50% of our patients were fixed with hemiarthroplasty or total hip replacement and were therefore excluded. 184 patients were included in the analysis. There was a significant association of higher DAP with fracture subtype (P=0.001), fracture complexity (P<0.001), if an additional implant was used (P=0.001), if fixation was satisfactory (P=0.002) and the operative time (P<0.001). DAP was higher in PFNA than DHS and greatest in Long PFNA. There was some evidence of association between the level of the surgeon and DAP, although this was not statistically significant (P=0.069) and remained not significant after adjusting for the variables (fracture complexity, fixation or implant used) (p=0.32). Conclusions. Increased radiation in proximal femur fractures is seen in fixation of complex fractures, certain subtypes, the type of implant used and if an additional implant was required. Seniority of surgeon did not result in less radiation exposure even when adjusting for other factors, which is in contrast to other published studies

Aim. Our aim was to compare the Wilkins'-modified Gartland classification and AO classifications of supracondylar humeral fracture with respect to: -Inter-observer reliability; Association of fracture-grade with radiological quality of reduction; Association of fracture-grade with complications. Methods. The unit database was interrogated to identify all operated supracondylar fractures between 2007–2011. Radiographs from each case were evaluated by four observers (three consultants, one trainee) and classified according to Gartland and the AO system. Inter-observer reliability was calculated using Cohen's Kappa coefficient. Radiological quality of reduction was evaluated using a new scoring system, combining the anterior humeral line, the lateral capitello-humeral angle (LCHA) and Baumann's angle, (compared to reference values). Analysis of variance (ANOVA) was performed to determine whether there was a statistically significant difference in scores between the fracture grades. Case notes were reviewed for pre- and post-operative complication, and chi-squared test performed to compare the incidence between different fracture grades. Results. 83 cases were identified for fracture classification and 66 for assessment of reduction and complications. Inter-observer reliability was 0.58 for Gartland (moderate agreement), and 0.70 for the AO classification (good agreement). ANOVA demonstrated no significant difference in the overall reduction scores between the different grades of either classification. Mean scores for LCHA were lower for Gartland-2b (p=0.02) and AO-3 (p=0.007) groups (compared to Gartland-3 and AO-4). Complications were more frequent with the higher grades of fracture in both classifications (p<0.05). Conclusion. The AO classification has greater reliability and should be considered as an alternative to the Gartland classification. A higher grade of fracture is not associated with inferior radiographic outcomes. Surgeons should be aware that restoration of the LCHA is more difficult with the Gartland-2b and AO-3 fractures, probably because of the intact posterior cortex. A greater rate of complications should be expected with higher grades of fracture

Purpose: Classification systems for orthopaedic injuries are used in clinical care and research to allow for communication about the diagnosis, prognosis, treatment, and outcome of fractures and dislocations. The inter-observer reliability of the Hotchkiss modification of the Mason classification system and the AO classification system were evaluated to assess their reliability in classifying radial head fractures. Methods: Forty-three consecutive fractures with and without other associated injuries were identified from the practice of a single sub-specialist orthopaedic surgeon. Their radiographs were compiled and all identifying marks were hidden. Five observers classified the radiographs according to each classification system. Percent agreement was calculated pair-wise between observers for each system. The mean percent agreement and 95% confidence intervals were calculated for each system. Additionally, the systems were collapsed, with types II and III combined for the Hotchkiss system, and the final digit dropped for the AO system. The mean percent agreement and 95% confidence intervals were then recalculated. Results: The percent agreement for the Hotchkiss modification of the Mason classification system was 72.3% (95% CI 65.8% to 78.9%). The percent agreement for the AO classification system was 37.7% (95% CI 30.5% to 44.9%). The percent agreement for the collapsed Hotchkiss system was 89.3% (95% CI 86.6% to 92.0%). The percent agreement for the collapsed AO system was 67.4% (95% CI 54.6% to 80.3%). Conclusions: The inter-observer reliability for the AO classification system had a low percent agreement, possibly reflecting the complexity of the system. Collapsing the AO system improved the percent agreement, however it still could be considered fair. The inter-observer reliability for the Hotchkiss modification of the Mason classification system was higher. However, when the lower end of the 95% confidence interval is taken into consideration, the reliability of the system could be considered fair. Collapsing this system did improve the percent agreement into what could be considered a good range, suggesting that this system may be able to reliably identify fractures requiring operative treatment. Funding: Other Education Grant. Funding Parties: Alberta Heritage Foundation for Medical Research

To conduct a meta-analysis for intertrochanteric hip fractures comparing in terms of efficacy and safety short versus long intralomedullary nails. A pubmed search of the last 10 years for intertrochanteric fracture 31A1-31A3 according to the AO/OTA classification was performed. Baseline characteristics of each article were obtained, complication measures were analyzed: Peri-implant fracture, reoperations, deep/superficial infection, and mortality. Clinical variables consisted of blood loss (mL), length of stay (days), time of surgery (min) and nº of transfusions. Functional outcomes were also recorded. A meta-analysis was performed with Review Manager 5.4. Twelve studies were included, nine were retrospective. The reoperations rate was lower in the short nail group and the peri-implant fracture rate was lower in the long nail group (OR 0.58, 95% CI 0.38 to 0.88) (OR 1.88, 95% CI 1.04 to 3.43). Surgery time and blood loss was significantly higher in the long nail group (MD −12.44, 95% CI −14.60 to −10.28) (MD −19.36, 95% CI −27.24 to −11.48). There were no differences in functional outcomes. The short intramedullary nail has a higher risk of peri-implant fracture; however, the reoperation rate is lower compared to the long nail. Blood loss and surgery time was higher in the long nail group

Aim. Determine the incidence of surgical site infections (SSI) after intramedullary nailing (IN) of femoral and tibial diaphyseal fractures and evaluate possible risk factors. Method. Prospective observational cohort study. SSI was defined according to CDC-NHSN criteria and surveillance period for the occurrence of infection was 12 months instead of the 90 days currently recommended. Incidence was calculated as the ratio between the number of patients with SSI and total number of patients. Analysis of potential risk factors included patients-related factors (age, gender, body mass index, active foci of infection, immunosuppressive conditions, ASA score, alcohol or illicit drug abuse, smoking, polytrauma, etiology of fracture, type of fracture if closed or open, classification of fracture according to Müller AO, Tcherne classification for closed fractures, Gustilo-Anderson classification and duration of bone exposure for open fractures, previous stay in other healthcare services, use of external fixator, previous surgical manipulation at same topography of fracture, use of blood products); environmental and surgical-related factors (surgical wound classification, duration of surgery, hair removal, intraoperative contamination, antimicrobial use, presence of drains, hypothermia or hypoxia in the perioperative period, type of IN used, reaming, need for muscle or skin flap repair, use of negative pressure therapy) and microbiota-related factors (presence of preoperative colonization by Staphylococcus aureus or Acinetobacter baumannii). Results. 221 patients were included and completed the 12-month follow-up period. Incidence of SSI was 11.8% after 12-month follow-up, but would be 8.59% if used the 90-day vigilance period currently recommended. In the initial analysis by unadjusted logistic regression, following factors were associated SSI: Müller AO classification of the fracture morphology groups 2 or 3, previous use of external fixator, presence of drains, use of negative pressure therapy and need for muscle or skin flap repair. Preoperative colonization by S. aureus or A. baumannii was not associated with occurrence of infection. In the multiple logistic regression-adjusted analysis, only previous use of external fixator and need for muscle or skin flap repair remained associated with SSI. Conclusions. Incidence of SSI associated with IN for femoral and tibial diaphyseal fractures was 11.8%, but currently recommended vigilance period would be less sensitive for SSI detection after fracture fixation. Previous use of external fixators and need for muscle or skin flap repair were factors associated with occurrence of IN related infection

The lateral wall thickness (LWT) in trochanteric femoral fractures is a known predictive factor for postoperative fracture stability. Currently, the AO/OTA classification uses a patient non-specific measure to assess the absolute LWT (aLWT) and distinguish stable A1.3 from unstable A2.1 fractures based on a threshold of 20.5 mm. This approach potentially results in interpatient deviations due to different bone morphologies and consequently variations in fracture stability. Therefore, the aim of this study was to explore whether a patient-specific measure for assessment of the relative LWT (rLWT) results in a more precise threshold for prediction of unstable fractures. Part 1 of the study evaluated 146 pelvic radiographs to assess left-right symmetry with regard to caput-collum-angle (CCD) and total trochanteric thickness (TTT), and used the results to establish the rLWT measurement technique. Part 2 reevaluated 202 patients from a previous study cohort to analyze their rLWT versus aLWT for optimization purposes. Findings in Part 1 demonstrated a bilateral symmetry of the femur regarding both CCD and TTT (p ≥ 0.827) allowing to mirror bone's morphology and geometry from the contralateral intact to the fractured femur. Outcomes in Part 2 resulted in an increased accuracy for the new determined rLWT threshold (50.5%) versus the standard 20.5 mm aLWT threshold, with sensitivity of 83.7% versus 82.7% and specificity 81.3% versus 77.8%, respectively. The novel patient-specific rLWT measure can be based on the contralateral femur anatomy and is a more accurate predictor of a secondary lateral wall fracture in comparison to the conventional aLWT. This study established the threshold of 50.5% rLWT as a reference value for prediction of fracture stability and selection of an appropriate implant for fixation of trochanteric femoral fractures