Aim. The most frequent mechanical failure in the osteosynthesis of intertrochanteric fractures is the cut-out. Fracture pattern, reduction quality, tip-apex distance or the position of the cervico-cephalic screw are some of the factors that have been associated with higher cut-out rates. To date, it has not been established whether underlying bacterial colonization or concomitant infection may be the cause of osteosynthesis failure in proximal femur fractures (PFF). The primary objective of this study is to assess the incidence of infection in patients with cut-out after PFF osteosynthesis. Method. Retrospective cohort study on patients with cut-out after PFF osteosynthesis with endomedullary nail, from January 2007 to December 2020. Demographic data of patients (such as sex, age, ASA), fracture characteristics (pattern, laterality, causal mechanism) and initial surgery parameters were collected (time from fall to intervention, duration of surgery, intraoperative complications). Radiographic parameters were also analyzed (tip-apex distance and Chang criteria). In all cut-out cases, 5 microbiological cultures and 1 anatomopathological sample were taken and the osteosynthesis material was sent for sonication. Fracture-related infection (FRI) was diagnosed based on Metsemakers et al (2018) and McNally et al (2020) diagnostic criteria. Results. Of the 67 cut-out cases, 16 (23.9%) presented clinical, analytical or microbiological criteria of infection. Of these sixteen patients, only in 3 of them the presence of an underlying infection was suspected preoperatively. A new osteosynthesis was performed in 24 cases (35.8%) and a conversion to arthroplasty in the remaining 43 (64.2%). A comparative analysis was performed between cases with and without infection. The groups were comparable in terms of demographic data and postoperative radiological data (using Chang criteria and tip-apex distance). Patients with underlying infection had a higher rate of surgical wound complication (56.3% vs 22%, p = 0.014), higher rates of leukocytes counts (11.560 vs 7.890, p = 0.023) and time to surgery (5.88 vs 3.88 days, p = 0.072). Conclusions. One out of four osteosynthesis failure in PFF is due to underlying FRI and in almost 20% were not unsuspected before surgery. In PFF osteosynthesis failures, underlying infection should be taken into account as a possible etiological factor and thus a preoperative and intraoperative infection study should be always performed

Acetabular fractures can occur due to either low or high-energy trauma, and treatment can consist of non-operative management, open reduction and internal fixation (ORIF), or total hip arthroplasty in either the acute or chronic setting. These decisions are often based on the age of the patient, the fracture pattern, and the existence of pre-fracture hip debility. In the acute setting, younger patients should undergo ORIF with anatomic reduction of the fracture, while total hip arthroplasty (THA) may be considered for elderly patients with pre-existing hip arthritis. Several factors can expedite the onset of post-traumatic arthritis in the former, including difficult fracture patterns, fractures that are intra-articular in nature, or fractures involving the femoral head. A meta-analysis of seven studies with 685 patients from all age groups reported the incidence of post-traumatic arthritis following satisfactory reduction of acetabular fractures (≤2 mm) to be 13.2%. Unsatisfactory reductions (>2 mm) increased the incidence of post-traumatic arthritis to 43.5%. Factors affecting the reduction quality include fracture type, fracture characteristics (e.g. comminution, impaction), time to surgery, and experience level of the operative team. In such settings, salvage THAs can be considered. However, complications including aseptic loosening, instability, and periprosthetic infection are more common than for other indications leading to THA. In our experience, at 20 years, we found that THAs performed after operatively treated acetabular fractures still had excellent hip function, and a 70% survivorship free of aseptic acetabular revision. A more recent study of 30 primary THAs performed with highly porous acetabular components indicated excellent results as well. As such, if early complications can be avoided, patients can expect substantial pain relief and excellent durability

Several preoperative planning tools in computer-assisted surgery in acetabular fractures have been proposed. Moreover, all these preoperative planning tools are based on geometrical repositioning with their own limitations. The aim of this study was to evaluate the value of our prototype virtual planning tool using a rigid biomechanical model to predict failure in fracture reduction. Between November of 2015 and June of 2016, 10 patients were operated by the main author for acetabular fracture in our institution. To validate our biomechanical model planning tool, biomechanical simulation was performed for each patient immediately after the surgery. Reduction quality was assessed on post-operative CT scans. A 3D model of the acetabular fracture was build out of the CT images using the non-commercial software Itksnap. Then a biomechanical model implemented within the non-commercial Artisynth framework was used to perform virtual reduction. Surgical approach and surgical strategy according to the operative report were simulated. The simulated reductions and the surgical reductions were compared. The same reductions were obtained during surgery and biomechanical simulation in the 10 cases. For 7 cases, reduction was achieved by anterior surgical approach and so was the simulation. For 3 cases, reduction was achieved by posterior surgical approach and so was the simulation. The biomechanical simulation found similar results using the same surgical strategy with 9 anatomical reductions (90%) and one imperfect reduction (10%). The mean duration to perform acetabular planning surgery was 24 +/− 9 min [16–38]. Our virtual planning tool using a rigid biomechanical model can predict success or failure in fracture reduction according to the surgical approach and the surgical strategy

Surgeons need to be able to measure angles and distances in three dimensions in the planning and assessment of knee replacement. Computed tomography (CT) offers the accuracy needed but involves greater radiation exposure to patients than traditional long-leg standing radiographs, which give very little information outside the plane of the image.

There is considerable variation in CT radiation doses between research centres, scanning protocols and individual scanners, and ethics committees are rightly demanding more consistency in this area.

By refining the CT scanning protocol we have reduced the effective radiation dose received by the patient down to the equivalent of one long-leg standing radiograph. Because of this, it will be more acceptable to obtain the three-dimensional data set produced by CT scanning. Surgeons will be able to document the impact of implant position on outcome with greater precision.