Risk factors associated with delayed and aseptic nonunion following tibial diaphyseal fractures managed with intramedullary nailing

Anti-Microbial Drug Metronidazole Promotes Fracture Healing: Enhancement in the Bone Regenerative Efficacy of the Drug by a Biodegradable Sustained-Release In Situ Gel Formulation

Nitroimidazoles comprise a class of broad-spectrum anti-microbial drugs with efficacy against parasites, mycobacteria, and anaerobic Gram-positive and Gram-negative bacteria. Among these drugs, metronidazole (MTZ) is commonly used with other antibiotics to prevent infection in open fractures. However, the effect of MTZ on bone remains understudied. In this paper, we evaluated six nitroimidazole drugs for their impact on osteoblast differentiation and identified MTZ as having the highest osteogenic effect. MTZ enhanced bone regeneration at the femur osteotomy site in osteopenic ovariectomized (OVX) rats at the human equivalent dose. Moreover, in OVX rats, MTZ significantly improved bone mass and strength and improved microarchitecture compared to the vehicle-treated rats, which was likely achieved by an osteogenic mechanism attributed to the stimulation of the Wnt pathway in osteoblasts. To mitigate the reported neurological and genotoxic effects of MTZ, we designed an injectable sustained-release in situ gel formulation of the drug that improved fracture healing efficacy by 3.5-fold compared to oral administration. This enhanced potency was achieved through a significant increase in the circulating half-life and bioavailability of MTZ. We conclude that MTZ exhibits osteogenic effects, further accentuated by our sustained-release delivery system, which holds promise for enhancing bone regeneration in open fractures.

RISK FACTORS AT NON-UNION OF TIBIAL FRACTURE TREATED WITH INTRAMEDULLARY NAIL

Objective

Identify the predictors associated with delayed union at 6 months and non-union at 12 months in tibial shaft fractures treated with intramedullary nailing (IMN).

Methods

This retrospective longitudinal study included a cohort of 218 patients who sustained tibial shaft fractures and received IMN between January 2015 and March 2022. We gathered data on a range of risk factors, including patient demographics, trauma intensity, associated injuries, fracture characteristics, soft tissue injuries, comorbidities, addictions, and treatment-specific factors. We employed logistic bivariate regression analysis to explore the factors predictive of delayed union and non-union.

Results

At the 6-month follow-up, the incidence of delayed union was 28.9%. Predictors for delayed union included flap coverage, high-energy trauma, open fractures, the use of external fixation as a staged treatment, the percentage of cortical contact in simple type fractures, RUST score, and postoperative infection. After 12 months, the non-union rate was 15.6%.

Conclusion

the main predictors for non-union after IMN of tibial shaft fractures are related to the trauma energy. Furthermore, the initial treatment involving external fixation and postoperative infection also correlated with non-union. Level of Evidence III; Retrospective Longitudinal Study.

Approach to Tibial Shaft Nonunions: Diagnosis and Management

The tibia is the most common long bone at risk for nonunion with an annual incidence ranging from 12% to 19%. This topic continues to be an area of research as management techniques constantly evolve. A foundational knowledge of the fundamental concepts, etiology, and risk factors for nonunions is crucial for success. Treatment of tibial shaft nonunions often requires a multidisciplinary effort. This article provides guidance based on the most recent literature that can be used to aid the treating provider in the diagnosis, workup, and management of tibial shaft nonunions.

Outcome Following Intramedullary Nailing of Tibial Diaphyseal Fractures: Suprapatellar Nail Insertion Results in Superior Radiographic Parameters But No Difference in Mid-Term Function

BACKGROUND

The primary aim of this study was to compare the radiographic parameters (nail insertion-point accuracy [NIPA] and fracture malalignment) of patients who had undergone tibial intramedullary nailing via the suprapatellar (SP) and infrapatellar (IP) approaches. The secondary aims were to compare clinical outcomes and patient-reported outcomes (PROs) between these approaches.

METHODS

All adult patients with an acute tibial diaphyseal fracture who underwent intramedullary nailing at a single level-I trauma center over a 4-year period (2017 to 2020) were retrospectively identified. The nailing approach (SP or IP) was at the treating surgeon's discretion. Intraoperative and immediate postoperative radiographs were reviewed to assess NIPA (mean distance from the optimal insertion point) and malalignment (≥5°). Medical records and radiographs were reviewed to evaluate the rates of malunion, nonunion, and other postoperative complications. The Oxford and Lysholm Knee Scores (OKS and LKS) and patient satisfaction (0 = completely dissatisfied, 100 = completely satisfied) were obtained via a postal survey at a minimum of 1 year postoperatively.

RESULTS

The cohort consisted of 219 consecutive patients (mean age, 48 years [range, 16 to 90 years], 51% [112] male). There were 61 patients (27.9%) in the SP group and 158 (72.1%) in the IP group. The groups did not differ in baseline demographic or injury-related variables. SP nailing was associated with superior coronal NIPA (p < 0.001; 95% confidence interval [CI] for IP versus SP, 1.17 to 3.60 mm) and sagittal NIPA (p < 0.001; 95% CI, 0.23 to 0.97 mm) and with a reduced rate of malalignment (3% [2 of 61] versus 11% [18 of 158] for IP; p = 0.030). PROs were available for 118 of 211 patients (56%; 32 of 58 in the SP group and 86 of 153 in the IP group) at a mean of 3 years (range, 1.2 to 6.5 years). There was no difference between the SP and IP groups in mean OKS (36.5 versus 39.6; p = 0.246), LKS (71.2 versus 73.5; p = 0.696), or satisfaction scores (81.4 versus 79.9; p = 0.725).

CONCLUSIONS

Compared with IP nailing, SP nailing of tibial shaft fractures was associated with superior NIPA and a reduced rate of intraoperative malalignment but not of malunion at healing. However, the superior NIPA may not be clinically important. Furthermore, there were no differences in PROs at mid-term follow-up.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Ketorolac and bone healing: a review of the basic science and clinical literature

Although the efficacy of ketorolac in pain management and the short duration of use align well with current clinical practice guidelines, few studies have specifically evaluated the impact of ketorolac on bony union after fracture or surgery. The purpose of this study was to review the current basic science and clinical literature on the use of ketorolac for pain management after fracture and surgery and the subsequent risk of delayed union or nonunion. Animal studies demonstrate a dose-dependent risk of delayed union in rodents treated with high doses of ketorolac for 4 weeks or greater; however, with treatment for 7 days or low doses, there is no evidence of risk of delayed union or nonunion. Current clinical evidence has also shown a dose-dependent increased risk of pseudoarthrosis and nonunion after post-operative ketorolac administration in orthopedic spine surgery. However, other orthopedic subspecialities have not demonstrated increased risk of delayed union or nonunion with the use of peri-operative ketorolac administration. While evidence exists that long-term ketorolac use may represent risks with regard to fracture healing, insufficient evidence currently exists to recommend against short-term ketorolac use that is limited to the peri-operative period. LEVEL OF EVIDENCE V: Narrative Review.

Functional outcome after nonoperative management of minimally displaced greater tuberosity fractures and predictors of poorer patient experience

The outcomes following nonoperative management of minimally displaced greater tuberosity (GT) fractures, and the factors which influence patient experience, remain poorly defined. We assessed the early patient-derived outcomes following these injuries and examined the effect of a range of demographic- and injury-related variables on these outcomes. In total, 101 patients (53 female, 48 male) with a mean age of 50.9 years (19 to 76) with minimally displaced GT fractures were recruited to a prospective observational cohort study. During the first year after injury, patients underwent experiential assessment using the Disabilities of the Arm, Shoulder and Hand (DASH) score and assessment of associated injuries using MRI performed within two weeks of injury. The primary outcome was the one-year DASH score. Multivariate analysis was used to assess the effect of patient demographic factors, complications, and associated injuries, on outcome. The mean DASH score improved from 42.3 (SD 9.6) at six weeks post-injury, to 19.5 (SD 14.3) at one-year follow-up (p < 0.001), but outcomes were mixed, with 30 patients having a DASH score > 30 at one year. MRI revealed a range of associated injuries, with a full-thickness rotator cuff tear present in 19 patients (19%). Overall, 11 patients (11%) developed complications requiring further operative intervention; 20 patients (21%) developed post-traumatic secondary shoulder stiffness. Multivariate analysis revealed a high-energy mechanism (p = 0.009), tobacco consumption (p = 0.033), use of mobility aids (p = 0.047), a full-thickness rotator cuff tear (p = 0.002), and the development of post-traumatic secondary shoulder stiffness (p = 0.035) were independent predictors of poorer outcome. The results of nonoperative management of minimally displaced GT fractures are heterogeneous. While many patients have satisfactory early outcomes, a substantial subgroup fare much worse. There is a high prevalence of rotator cuff injuries and post-traumatic shoulder stiffness, and their presence is associated with poorer patient experience. Furthermore, patients who have a high-energy injury, smoke, or use walking aids, have worse outcomes.

Bone Healing Gone Wrong: Pathological Fracture Healing and Non-Unions-Overview of Basic and Clinical Aspects and Systematic Review of Risk Factors

Bone healing is a multifarious process involving mesenchymal stem cells, osteoprogenitor cells, macrophages, osteoblasts and -clasts, and chondrocytes to restore the osseous tissue. Particularly in long bones including the tibia, clavicle, humerus and femur, this process fails in 2-10% of all fractures, with devastating effects for the patient and the healthcare system. Underlying reasons for this failure are manifold, from lack of biomechanical stability to impaired biological host conditions and wound-immanent intricacies. In this review, we describe the cellular components involved in impaired bone healing and how they interfere with the delicately orchestrated processes of bone repair and formation. We subsequently outline and weigh the risk factors for the development of non-unions that have been established in the literature. Therapeutic prospects are illustrated and put into clinical perspective, before the applicability of biomarkers is finally discussed.

Fracture Healing in the Setting of Endocrine Diseases, Aging, and Cellular Senescence

More than 2.1 million age-related fractures occur in the United States annually, resulting in an immense socioeconomic burden. Importantly, the age-related deterioration of bone structure is associated with impaired bone healing. Fracture healing is a dynamic process which can be divided into four stages. While the initial hematoma generates an inflammatory environment in which mesenchymal stem cells and macrophages orchestrate the framework for repair, angiogenesis and cartilage formation mark the second healing period. In the central region, endochondral ossification favors soft callus development while next to the fractured bony ends, intramembranous ossification directly forms woven bone. The third stage is characterized by removal and calcification of the endochondral cartilage. Finally, the chronic remodeling phase concludes the healing process. Impaired fracture healing due to aging is related to detrimental changes at the cellular level. Macrophages, osteocytes, and chondrocytes express markers of senescence, leading to reduced self-renewal and proliferative capacity. A prolonged phase of "inflammaging" results in an extended remodeling phase, characterized by a senescent microenvironment and deteriorating healing capacity. Although there is evidence that in the setting of injury, at least in some tissues, senescent cells may play a beneficial role in facilitating tissue repair, recent data demonstrate that clearing senescent cells enhances fracture repair. In this review, we summarize the physiological as well as pathological processes during fracture healing in endocrine disease and aging in order to establish a broad understanding of the biomechanical as well as molecular mechanisms involved in bone repair.

Treatment of tibial shaft nonunion with a retained nail in morbidly obese patients

PURPOSE

Morbid obesity is a rising worldwide health problem. Tibial shaft nonunion with retained intramedullary nail (IMN) in the morbidly obese is a challenging orthopaedic problem. Prolonged immobilization carries a significant risk of complications. This study aimed to investigate whether decortication and cancellous bone grafting with the application of a circular external fixator (CEF) over the preexisting IMN can achieve fracture union and avoid serious complications.

METHODS

We retrospectively reviewed 27 consecutive morbidly obese patients treated for tibial diaphysis aseptic nonunion after failed IMN. All cases were treated with osteoperiosteal decortication, cancellous bone grafting, and fixation with CEF over the IMN. Peri-operative multidisciplinary patient evaluation included internal medicine, cardiology, chest, vascular surgery, and anesthesia consultations. The union rate, bone results, functional results, and complications were recorded.

RESULTS

The mean age of the patients was 37.9 years. The mean BMI was 45.8. Sixteen cases (59.3%) were treated for hypertrophic nonunion, while 11 cases (40.7%) were treated for atrophic nonunion. Seven cases (25.9%) had open initial injury, 14 cases (51.9%) had associated comorbidities, and seven cases (25.9%) were smokers. Twenty-six cases united. The mean time to union was 5.2 months. Bone results and functional results were good to excellent in 96.3% of the cases. We recorded 25 complications in 21 patients. However, most of the complications were minor.

CONCLUSION

Decortication and cancellous bone grafting with the application of CEF over the preexisting nail is a safe and reliable treatment method for aseptic tibial shaft nonunion with retained IMN in morbidly obese patients.