Incidental findings detected on preoperative CT imaging obtained for robotic-assisted joint replacements: clinical importance and the effect on the scheduled arthroplasty

The Value of Computed Tomography Scan in Three-dimensional Planning and Intraoperative Navigation in Primary Total Hip Arthroplasty

Total hip arthroplasty (THA) is a frequently performed procedure; the objective is restoration of native hip biomechanics and achieving functional range of motion (ROM) through precise positioning of the prosthetic components. Advanced three-dimensional (3D) imaging and computed tomography (CT)-based navigation are valuable tools in both the preoperative planning and intraoperative execution. The aim of this study is to provide a thorough overview on the applications of CT scans in both the preoperative and intraoperative settings of primary THA. Preoperative planning using CT-based 3D imaging enables greater accuracy in prediction of implant sizes, leading to enhancement of surgical workflow with optimization of implant inventory. Surgeons can perform a more thorough assessment of posterior and anterior acetabular wall coverage, acetabular osteophytes, anatomical landmarks, and thus achieve more functional implant positioning. Intraoperative CT-based navigation can facilitate precise execution of the preoperative plan, to attain optimal positioning of the prosthetic components to avoid impingement. Medial reaming can be minimized preserving native bone stock, which can enable restoration of femoral, acetabular, and combined offsets. In addition, it is associated with greater accuracy in leg length adjustment, a critical factor in patients' postoperative satisfaction. Despite the higher costs and radiation exposure, which currently limits its widespread adoption, it offers many benefits, and the increasing interest in robotic surgery has facilitated its integration into routine practice. Conducting additional research on ultra-low-dose CT scans and examining the potential for translation of 3D imaging into improved clinical outcomes will be necessary to warrant its expanded application.

Arithmetic hip knee angle measurement on long leg radiograph versus computed tomography-inter-observer and intra-observer reliability

BACKGROUND

Pre-operative alignment is important for knee procedures including total knee arthroplasty (TKA), especially when considering alternative alignments. The arithmetic Hip Knee Angle (aHKA) is a measure of coronal alignment calculated using the medial proximal tibial (MPTA) and lateral distal femoral angles (LDFA). Traditionally, aHKA is measured on long leg radiographs (LLR). This study assesses the reproducibility of aHKA measurement on LLR and robotic-assisted TKA planning CT.

METHODS

Sixty-eight TKA patients with pre-operative LLR and planning CTs were included. Three observers measured the LDFA, MPTA and aHKA three times on each modality and intra-observer and inter-observer reliability was calculated. Statistical analysis was undertaken with Pearson's r and the Bland-Altman test.

RESULTS

Mean intra-observer coefficient of repeatability (COR) for LLR vs. CT: MPTA 3.50° vs. 1.73°, LDFA 2.93° vs. 2.00° and aHKA 2.88° vs. 2.57° for CT. Inter-observer COR for LLR vs. CT: MPTA 2.74° vs. 1.28°, LDFA 2.31° vs. 1.92°, aHKA 3.56° vs. 2.00°. Mean intra-observer Pearson's r for MPTA was 0.93 for LLR and 0.94 for CT, LDFA 0.90 for LLR and 0.91 for CT and aHKA 0.92 for LLR and 0.94 for CT. Inter-observer Pearson's r for LLR compared to CT: MPTA 0.93 vs. 0.97, LDFA 0.91 vs. 0.90, aHKA 0.91 and 0.95.

CONCLUSION

When compared to LLR, CT measurements of MPTA, LDFA and aHKA are more reproducible and have a good correlation with LLR measurement. CT overcomes difficulties with positioning, rotation, habitus and contractures when assessing coronal plane alignment and may obviate the need for LLRs.

Ultrasound evaluations and guided procedures of the painful joint arthroplasty

The purpose of this article is to describe the use of ultrasound for the diagnosis and treatment of painful joint arthroplasty. Ultrasound plays a crucial role in the diagnosis of the painful joint arthroplasty, especially given its unique dynamic capabilities, convenience, and high resolution. Ultrasound guidance is also instrumental for procedures in both diagnosing and in select cases, treating the painful joint arthroplasty. Topics to be discussed in this article include trends in arthroplasty placement, benefits of the use of ultrasound overall, and ultrasound evaluation of periprosthetic joint infections. We will also review the sonographic findings with dissociated/displaced components and adverse reaction to metallic debris including metallosis, trunnionosis, and metal-on-metal pseudotumors. Additionally, we will discuss ultrasound evaluation of tendon pathologies with arthroplasties, including dynamic maneuvers to evaluate for tendon impingement/snapping. Finally, we will cover ultrasound-guided joint arthroplasty injection indications and precautions. KEY POINTS: • Ultrasound is preferred over MRI in patients with joint arthroplasty and plays a crucial role in diagnosis, especially given its unique dynamic capabilities, convenience and high resolution. • It is especially beneficial for US-guided aspiration in periprosthetic joint infections; effectively used to evaluate periprosthetic fluid collections, facilitating differentiation between abscesses and aseptic collections, and tracking sinus tracts. • Recently, the diagnosis of periprosthetic joint infections has shifted focus to biomarkers in the periprosthetic fluid, specifically α-defensin, which has a high sensitivity and specificity for diagnosing infection. • Cutibacterium acnes is a major pathogen responsible for shoulder arthroplasty infections, often presenting with normal laboratory values and since slow growing, must be kept for a minimum of 14 days.

Imaging in Hip Arthroplasty Management-Part 1: Templating: Past, Present and Future

Hip arthroplasty is a frequently used procedure with high success rates. Its main indications are primary or secondary advanced osteoarthritis, due to acute fracture, osteonecrosis of the femoral head, and hip dysplasia. The goals of HA are to reduce pain and restore normal hip biomechanics, allowing a return to the patient’s normal activities. To reach those goals, the size of implants must suit, and their positioning must meet, quality criteria, which can be determined by preoperative imaging. Moreover, mechanical complications can be influenced by implant size and position, and could be avoided by precise preoperative templating. Templating used to rely on standard radiographs, but recently the use of EOS^® imaging and CT has been growing, given the 3D approach provided by these methods. However, there is no consensus on the optimal imaging work-up, which may have an impact on the outcomes of the procedure. This article reviews the current principles of templating, the various imaging techniques used for it, as well as their advantages and drawbacks, and their expected results.