CT of Periarticular Adult Knee Fractures: Classification and Management Implications.

Periarticular knee fractures, which include fractures of the distal femur, tibial plateau, and patella, account for 5%-10% of musculoskeletal injuries encountered in trauma centers and emergency rooms. These injuries are frequently complex, with articular surface involvement. Surgical principles center on reconstruction of the articular surface as well as restoration of limb length, alignment, and rotation to reestablish functional knee biomechanics. Fixation principles are guided by fracture morphology, and thus, CT with multiplanar reformats and volume rendering is routinely used to help plan surgical intervention. Fractures involving the distal femur, tibial plateau, and patella have distinct management considerations. This comprehensive CT primer of periarticular knee fractures promotes succinct and clinically relevant reporting as well as optimized communication with orthopedic trauma surgeon colleagues by tying fracture type and key CT findings with surgical decision making. Fracture patterns are presented within commonly employed fracture classification systems, rooted in specific biomechanical principles. Fracture typing of distal femur fractures and patellar fractures is performed using Arbeitsgemeinschaft für Osteosynthesefragen/Orthopedic Trauma Association (AO/OTA) classification schemes. Tibial plateau fractures are graded using the Schatzker system, informed by a newer explicitly CT-based three-column concept. For each anatomic region, the fracture pattern helps determine the surgical access required, whether bone grafting is warranted, and the choice of hardware that achieves suitable functional outcomes while minimizing the risk of articular collapse and accelerated osteoarthritis. Emphasis is also placed on recognizing bony avulsive patterns that suggest ligament injury to help guide stress testing in the early acute period. ©RSNA, 2024 Supplemental material is available for this article.

Modified Lightbulb Non-Vascularized Bone Grafting Technique for Osteonecrosis of the Femoral Head.

Multiple techniques for non-vascularized bone grafting for the treatment of femoral head osteonecrosis have been proposed with varying degrees of success. The success of these procedures may be improved with the use of ancillary growth and differentiation factors. The trephine (Phemister) technique allows for limited decompression of the femoral head through two percutaneous tunnels, while the direct approach through the femoral head ("trapdoor" technique) may result in damage to the articular cartilage. Herein we provide our modified "lightbulb" technique to decompress the femoral head through a window at the femoral head-neck junction that provides excellent, direct access to the osteonecrotic lesion. Adjuvant, non-vascularized bone graft, comprised of bone marrow aspiration concentrate (BMAC) and open matrix bone graft (MagnetOs Flex Matrix, Kuros Bioscience, Bilthoven, Netherlands) is a unique fibrillar and flexible structure that provides bone induction and further structural support to create a favorable environment for bone formation and healing. This is a straight-forward, hip-preserving, surgical technique that may be used for symptomatic management to delay, or potentially obviate, the need for total hip arthroplasty in patients who have medium- to large-sized or early-collapse lesions of the femoral head.

Surgical Technique: Core Decompression of Femoral Head Osteonecrosis with Bone Marrow Aspirate Concentrate.

Osteonecrosis of the femoral head is a progressive and potentially debilitating disorder that is responsive to core decompression, especially in early-stage disease. This is typically accomplished through use of an 8 to 10mm trephine or multiple, small-diameter percutaneous drilling. Use of the large diameter trephine is associated with risk of fracture and may not allow healing across large gaps. Here, we present a technique for core decompression using percutaneous drilling that allows bone marrow aspiration concentrate to be introduced. We used the aspirate needle to decompress the femoral head osteonecrotic lesion, followed by the administration of bone marrow aspirate concentrate. This is a straightforward procedure that can be used with low risk for patient morbidity.

Mako® Robotic-Arm Assisted Total Hip Arthroplasty: Avoiding Impingement with Updated THA Software.

The use of robotic-assisted total hip arthroplasty and three-dimensional computed tomography scan-based templating has become increasingly popular over the last 10 years. However, proper planning and execution are vital to producing optimal patient outcomes. In order to achieve these outcomes, the robotic-assisted system requires training, familiarity, and experience. The goal of this article is to provide clear and condensed examples of preoperative planning, as well as adjustments that one can make to avoid impingement. The surgical technique for robotic-assisted total hip arthroplasty is also briefly discussed. Examples will be given using the latest computed tomography (CT) scan-based robotic platform for osteoarthritic hips, with specific examples of various cases of impingement that might be encountered by the surgeon and how to ultimately avoid this problem when performing the arthroplasty. This article, through case histories, will discuss the various principles and adjustments that can be made to place components in the ideal location based on individual anatomy.

Does Fracture Pattern Really Predict Displacement of LC1 Sacral Fractures?

BACKGROUND: Operative management of minimally displaced lateral compression type-1 (LC1) pelvic ring injuries remains controversial. We aimed to assess the proportion of LC1 pelvic fractures that displaced following nonoperative management as a function of specific ring fracture patterns, and we quantified the magnitude of this displacement. METHODS: A retrospective review of the billing registry of a level-I trauma center was performed. Two hundred and seventy-three patients with a high-energy LC1 pelvic ring fracture and <5 mm of sacral displacement were included. The fracture pattern was characterized with use of computed tomography (CT) scans and radiographs. Absolute and interval pelvic ring displacement were quantified with use of previously described methodology. RESULTS: Thirty-five pelvic ring injuries (13%) were displaced. The rate of displacement was 31% (15 of 49) for LC1 injuries involving a complete sacral fracture and bilateral ramus fractures, 12% (7 of 58) for injuries involving a complete sacral fracture and a unilateral ramus fracture, and 10% (5 of 52) for injuries involving an incomplete sacral fracture and bilateral ramus fractures. In displaced injuries, the average interval displacement was 4.2 mm (95% confidence interval [CI], 1.8 to 6.8) and the final displacement was 9.9 mm ± 4.2 mm. CONCLUSIONS: Our study suggests that fracture characteristics can be used to predict the likelihood of displacement of LC1 fractures that are treated without surgery. To our knowledge, the present study is the first to describe the magnitude of displacement that may occur in association with LC1 pelvic ring injuries that are treated nonoperatively; however, further studies are needed to determine the clinical impact of this displacement. LEVEL OF EVIDENCE: Diagnostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Stacked Titanium Metaphyseal Cones for Reconstruction of Large Tibial Defects in Revision Knee Arthroplasty.

Failed total knee arthroplasties with large bone defects are increasing rapidly because of the growing population of young, active patients undergoing primary total knee arthroplasty. There are limited options when tibial metaphyseal bone loss is so extensive that a tibial component with augments and thickest available polyethylene cannot fill flexion and extension gaps once the femoral component is appropriately positioned. Previously, allograft or megaprostheses would be required. However, allografts require contouring and fixation and may not incorporate into surrounding bone. Most endoprostheses do not osseointegrate and are associated with high risk of failure. To our knowledge, we are the first to describe stacked porous titanium cones for reconstruction of massive tibial metaphyseal defects, a straightforward technique with standard revision implants highly likely to osseointegrate.

Normal Ranges of Upper Extremity Length, Circumference, and Rate of Growth in the Pediatric Population.

Background: Upper extremity length and circumference abnormalities are present in a number of conditions in the pediatric population. In most cases, upper limb hypoplasia and hypertrophy are diagnosed when one limb appears substantially different from the other during physical examination. However, occasionally when this discrepancy exists, it can be difficult to determine which limb is the abnormal one. The purpose of this study was to establish normal values for upper extremity length, circumference, and rate of growth in children aged 0 to 17 years. Methods: In all, 377 participants had 4 measurements taken of each upper extremity: upper arm length, upper arm circumference, forearm length, and forearm circumference. Statistical analysis was performed to identify differences and rates of growth. Results: Mean values for arm and forearm length and circumference for each age, 0 to 17 years, were established. The determination of a child's expected arm length is dependent on his or her height, age, and sex, while the calculation of a child's expected forearm length depends on his or her weight, age, and sex. Male and female arms and forearms have similar growth rates of lengths and circumferences. No significant differences were found between right and left extremities for each of the 4 measurements taken. Conclusions: Contralateral limbs can be used for comparison of length and circumference of the arm and forearm in cases of unilateral upper extremity abnormality. The establishment of normal values for upper extremity length, circumference, and growth rate will be a useful diagnostic tool for upper extremity hypoplasia and hypertrophy.