Experimental and finite element analysis studies of a reduction-force reducing traction method for pelvic fracture surgeries

Innovative development of robot reduction system in geriatric pelvic fractures: A single-center case series in Beijing, China

Displaced fragility fractures of the pelvis (FFP) pose significant challenges in orthopaedic trauma, owing to patient comorbidities, deteriorating bone quality, and surgical complexities. Despite technological advancements, no robotic methods have been documented for displaced FFP management. To address this, we introduced an advanced robot-assisted fracture reduction system, comprising a tracking device, path planning software, and robotic arms. This study evaluated fifteen consecutive patients with displaced FFP (average age 80.4 ± 9.1 years), who underwent robot-assisted reduction and internal fixation (RARIF) between January 2022 and May 2023. All were categorized as Rommens FFP type III, with a median time of 6 days (range 4-11) from injury to surgery. Operative times averaged 165 ± 44 min, with median blood loss of 50 mL. Postoperative radiographs showed all patients achieved excellent or good reductions as per Matta criteria, marking a 100 % success rate. A 6-month follow-up revealed an average modified Majeed score of 81.4, with 85.7 % of patients rated excellent or good. All fractures healed without complications. Leveraging our intelligent system, RARIF proves to be a safe and effective approach for displaced FFP, facilitating postoperative pain alleviation and early mobilization despite compromised health and bone conditions. This approach may revolutionize the management of FFP in an increasingly aging population, signaling a significant shift in therapeutic strategies. Translational Potential of this Article: Elderly patients with displaced FFP often present complex surgical challenges due to comorbidities and poor bone quality, complicating reduction procedures and often leading to ineffective fixation. Addressing these challenges, we have developed an innovative robot-assisted fracture reduction system, offering a practical alternative to conventional methods. This system optimizes the applied force and direction during the reduction process, thereby reducing the needs for manual and repetitive attempts. Our report, detailing the successful implementation of this technique in 15 FFP cases, signifies a considerable leap forward in the field of orthopaedic surgery. This technique notably benefits the elderly population, a group traditionally marginalized in receiving care for complex orthopedic conditions.

Intelligent robot-assisted fracture reduction system for the treatment of unstable pelvic fractures

BACKGROUND

Precise and minimally invasive closed reduction is the premise of minimally invasive internal fixation. This paper aims to explore the safety and efficacy of a robot-assisted fracture reduction system (RAFR) in the treatment of pelvic fractures and to analyze its clinical advantages and existing problems.

METHODS

The RAFR system intelligently designed the optimal reduction path and target position based on a preoperative three-dimensional(3D) CT scan of the patient. The reduction robotic arm automatically reduced the affected hemipelvis according to the pre-planned reduction path.

RESULTS

The average residual displacement was the 6.65 ± 3.59 mm. According to Matta's criteria, there were 7 excellent, 10 good, and 3 fair, and the excellent and good rate was 85%. No postoperative complications occurred.

CONCLUSION

In our study, the RAFR system could complete accurate and minimally invasive closed reduction for most patients with unstable pelvic fractures, which could achieve good fracture reduction quality and short-term efficacy.

Sagittal support rather than medial cortical support matters in geriatric intertrochanteric fracture: A finite element analysis study

Hip fracture, increasing exponentially with age, is osteoporosis's most severe clinical consequence. Intertrochanteric fracture, one of the main types of hip fracture, is associated with higher mortality and morbidity. The current research hotspots lay in improving the treatment effect and optimizing the secondary stability after intertrochanteric fracture surgery. Cortex buttress reduction is a widely accepted method for treating intertrochanteric fracture by allowing the head-neck fragment to slide and rigidly contact the femoral shaft's cortex. Medial cortical support is considered a more effective option in treating young patients. However, osteo-degenerations features, including bone weakness and cortical thickness thinning, affect the performance of cortex support in geriatric intertrochanteric fracture treatment. Literature focusing on the age-specific difference in cortex performance in the fractured hip is scarce. We hypothesized that this osteo-19 degenerative feature affects the performance of cortex support in treating intertrochanteric fractures between the young and the elderly. We established twenty models for the old and the young with intertrochanteric fractures and performed static and dynamic simulations under one-legged stance and walking cycle conditions. The von Mises stress and displacement on the femur, proximal femoral nail anti-rotation (PFNA) implant, fracture plane, and the cutting volume of cancellous bone of the femur were compared. It was observed that defects in the anterior and posterior cortical bone walls significantly increase the stress on the PFNA implant, the displacement of the fracture surface, and cause a greater volume of cancellous bone to be resected. We concluded that ensuring the integrity and alignment of the anterior and posterior cortical bones is essential for elderly patients, and sagittal support is recommended. This finding suggests that the treatment method for intertrochanteric fracture may differ, considering the patient's age difference.

Biomechanical characteristics of arteries during pelvic fracture reduction and dynamic simulation analysis

During robot-assisted reduction of pelvic fracture, blood vessels are susceptible to tensile and shear forces, making them prone to injury. Considering the impact of pelvic reduction on the risk of arterial injury, the biomechanical characteristics of arteries during the pelvic fracture reduction process are studied, and a refined coupled composite model of the damaged pelvic structure is established. Dynamic simulations of pelvic fracture reduction are conducted based on the planned reduction path. The simulation results show that during the reduction process, when the affected side is rotated, the stress and strain of the artery are maximum, particularly at the locations of the iliac common artery, internal iliac artery, and the superior gluteal artery arch endure significant stress and strain. After reduction, the maximum stress is observed in the right superior gluteal artery, and the maximum strain occurs at the intersection of the right iliac common artery. The stretch ratio of both the left and right iliac common arteries is considerable. Therefore, it can be concluded that the superior gluteal artery and the internal iliac artery are prone to injury, particularly the segment from the origin of the superior gluteal artery to its passage around the greater sciatic notch. After reduction, substantial traction on the iliac common artery, which makes it more susceptible to deformation, carries a risk of arterial rupture and aneurysm formation. This study provides a reference for planning the safe reduction path of pelvic fracture surgery and improving safety.

Biomechanical analysis of pelvic holding pathways and strategies for use of the steinmann pin in pelvic fracture reduction

Pelvic fracture is the most serious bone trauma and has the highest mortality and disability rate. Surgical treatment of pelvic fracture is very challenging for surgeons. Minimally invasive close reduction of pelvic fracture is considered the most difficult operation due to the complex pelvic morphology and abundant soft tissue anatomy, both of which increase the difficulty of pelvic fracture reduction. The most challenging aspect of such surgery is how to hold the pelvic bone and effectively transmit the reduction force to the bone. Therefore, a safe and effective pelvic holding pathway for reduction is necessary for pelvic fracture operations. Existing research on the pelvic holding pathway addresses anatomical position and dimension. Few studies have focused on biomechanical properties or on surgical techniques related to these pathways. This paper studies the three holding pathways that are most commonly used in clinical practice. The most effective force direction for each holding pathway is identified through finite element modeling. Pathway 1 is suitable for internal rotation operation and open/close-book operation of the pelvis; Pathway 2 is suitable for translation of the fractured pelvis toward the sacrum and internal pelvic rotation operations; Pathway 3 is suitable for pulling and lifting of the fractured pelvis against gravity and open/close-book operation of the pelvis. In addition, we find through our simulation that the use of a combined holding strategy can reduce the reduction force during the reduction process. We compared the performances of the 2-pin combined holding strategy (2P-CH) and the 3-pin combined strategy (3P-CH). During translational reduction, 2P-CH and 3P-CH showed little difference in pelvic reduction force. However, in rotational reduction, 3P-CH shows advantages. It has less reduction force and the least combined muscle resistance. It can also maximize the displacement of the iliac crest under the same conditions. The results of this study can be applied to surgical planning and to the development of robot-assisted surgery systems in selecting holding pathways and operation strategies for fractured pelvis.

Robot-Assisted Autonomous Reduction of a Displaced Pelvic Fracture: A Case Report and Brief Literature Review

Displaced pelvic fracture is among the most complicated fractures in traumatic orthopedics, with high mortality and morbidity. Reduction is considered a complex procedure as well as a key part in surgical treatment. However, few robotic techniques have been employed in the reduction of pelvic fracture, despite the rapid advancement of technologies. Recently, we designed a robot surgery system specialized in the autonomous reduction of displaced pelvic fracture and applied it in the true patient for the first time. In this paper, we report its successful clinical debut in the surgery of a displaced pelvic fracture. Total surgery time was 110 min and an anatomic reduction was achieved. We then present a brief overview of the literature about reduction techniques in pelvic fracture and introduce related principles involved in our robot-assisted reduction system.