Rates of interlock screw back-out are high with the retrograde femoral nailing advanced system for distal femur fractures.

PURPOSE: The retrograde femoral nailing advanced (RFNA) system (DePuy synthes) is a commonly used implant for the fixation of low distal femur and periprosthetic fractures. There is concern that the rate of distal interlock screw back-out may be higher for the RFNA compared to other nails (ON). The purpose of this study was to evaluate the incidence of interlock screw back-out and associated screw removal for RFNA versus ON, along with associated risk factors. METHODS: A retrospective comparative study of patients who underwent retrograde nailing for a distal femur fracture at an academic level one trauma center was performed. The incidence of distal interlock screw back-out and need for screw removal were compared for RFNA versus a propensity score matched cohort who received other nails. RESULTS: One hundred and ten patients underwent retrograde nailing with the RFNA for a distal femur fracture from 2015 to 2022 (average age: 66, BMI: 32, 52.7% smokers, 54.5% female, 61.8%). There was a significantly higher rate of interlock back-out in the RFNA group compared to the ON (27 patients, 24.5% vs 12 patients, 10.9%, p = 0.01), which occurred 6.3 weeks postoperatively. Screw removal rates for back-out were not significantly different for the RFNA group versus ON (8 patients, 7.3% vs 3 patients, 2.7%, p = 0.12). CONCLUSION: In this retrospective comparative study of distal femur fractures treated with retrograde nailing, the RFNA implant was associated with an increased risk of distal interlock screw back-out compared to other nails.

Statistical fragility analysis of reported outcomes associated with surgical management of acetabular labral pathology.

INTRODUCTION: The purpose of this study was to analyse the robustness of comparative research that evaluated arthroscopic labral reconstruction versus other surgical management of labral pathology. Key measures of statistical fragility include the fragility index and fragility quotient.ß. METHODS: 12 comparative studies that evaluated the use of arthroscopic labral reconstruction were included in this study. Particular attention was placed on evaluating trends, either statistically significant or not, of functional improvement, complication rates, need for total hip arthroplasty (THA) and revision rates with associated p-values. The analysis involved in this study was the Fragility Index, which is the median number of events required to change the statistical significance of a particular outcome, thus changing the study conclusions. Fragility quotient was calculated for each study as the fragility index divided by sample size. RESULTS: Of the 12 studies that were included for analysis, there were a total of 25 reported outcomes, 8 of which were statistically significant (p < 0.05). The statistical fragility for the significant outcomes were 2.5 (interquartile range [IQR]: 1.5-3.5), whereas the median statistical fragility for insignificant results was 6 (IQR 4-9). The overall fragility index was 4 (IQR 3-7). The median of fragility quotients was 0.04 (IQR 0.01-0.07). CONCLUSIONS: This study demonstrated that comparative research regarding arthroscopic techniques of labral reconstruction may not be as statistically stable as previously hoped. In many of the reported outcomes, particularly the ones that were statistically significant, only a small percentage of event changes was required to change the significance of the study conclusions. This fragility is worrisome, since clinical decisions that rely on these reported outcomes may have a significant impact on long-term patient outcomes. It is, therefore, crucial to optimise patient outcomes by incorporating past literature and reported outcomes.

The dynamic microenvironment associated with metastatic bone disease: Current concepts.

Patients with bone metastases may experience debilitating pain, neurological conditions, increased risk of pathological fractures, and death. A deeper understanding of the bone microenvironment, the molecular biology of cancer types prone to metastasis, and how bone physiology promotes cancer growth, may help to uncover targeted treatment options. The purpose of this paper is to outline the current concepts relevant to topics including bone remodeling, angiogenesis, and immunomodulation as it relates to metastatic bone disease.

The Antepsoas (ATP) Surgical Corridor for Lumbar and Lumbosacral Arthrodesis: A Radiographic, Anatomic, and Surgical Investigation.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To investigate the size of prepsoas surgical corridors, developed between the iliopsoas and prespinal vessels, at all disk levels between L1 and S1 granted by left and right lateral antepsoas (ATP) approaches. Secondary aims include evaluation of presurgery radiographic prepsoas windows between L1 and S1 with respect to the intraoperative findings. SUMMARY OF BACKGROUND DATA: The ATP technique is an evolving alternative to the transpsoas and direct anterior exposures for lumbar fusion. However, the vascular morphometric data of the ATP approach remain underexplored, especially at L5-S1. MATERIALS AND METHODS: Patients indicated for ATP lumbar-lumbosacral fusion between September 2018 and February 2020 were enrolled (n=121). Data were collected prospectively, including the following (in mm): intraoperative manual measurements of the premobilization psoas-vessel (pre-PV) window, the final postmobilization psoas-vessel (post-PV) window, and the preoperative radiographic psoas-to-vessel distance at the respective studied disk levels. RESULTS: A total of 121 patients (75 female, mean age: 55.3 yr, 81.8% right-sided approach) underwent a total of 279 levels of spinal fusion. Irrespective of the ATP access laterality, we noted ample postmobilization psoas-vessel (post-PV differential) corridors: largest at L4-L5 (36-38 mm) followed by L5-S1 (31-35 mm), L3-L4 (32-33 mm), L2-L3 (28-30 mm), and L1-L2 (20-24 mm). Similarly, the relative increases of the psoas-vessel corridors (post-PV and pre-PV differentials, averaged: 31 mm at L5-S1, 32 mm at L4-L5, 26 mm at L3-L4, 25 mm at L2-L3, and 14 mm at L1-L2) were also significant in both lateral approaches. In right flank approaches, the right vascular structures projected more dorsally compared with left-sided vasculature ( P <0.05). CONCLUSION: The ATP access offers generous bilateral prepsoas surgical windows to L1-S1 intervertebral disks, allowing for a safe anterior column release, decompression, instrumentation, and fusion.

The Role of Minimally Invasive Percutaneous Pedicle Screw Fixation for the Management of Spinal Metastatic Disease.

OBJECTIVE: Optimal surgical management of spinal metastatic disease remains controversial. Skip and diffuse spinal lesions, patient frailty, and the need for timely adjuvant chemoradiation complicate surgical decision-making. Minimally invasive percutaneous pedicle screw fixation (MIPSF) is an attractive concept that can confer stability and allow early postoperative mobilization. To date, outcomes of the MIPSF technique remain under-investigated. METHODS: A single-center retrospective review of patients undergoing percutaneous instrumentation for multilevel spinal metastatic disease between January 2012 and October 2020 was performed. Twenty-four patients were identified, and their primary tumor diagnoses, modified Tokuhashi scores, Spine Instability Neoplastic Scores, neurologic functions, pain scores, and procedure types were noted. Of these patients, 17 underwent fixation of 6 or more levels (L-MIPSF), whereas 7 underwent fixation of <6 levels (S-MIPSF). All patients had screw-and-rod constructs placed percutaneously using bi-planar fluoroscopy guidance. Patients undergoing corpectomy, multilevel laminectomies, or open posterior instrumentation were excluded. RESULTS: Improvement in pain and neurological function was noted in nearly all patients who underwent MIPSF. Average skin incision-to-closing time was 130 minutes, and standard deviation of 55 minutes. Likewise, the average estimated operative blood loss was 402 mL, and standard deviation of 388 mL. Only one patient required hardware revision due to proximal loss of fixation. Two patients required mini-open decompression procedures due to tumor recurrence at different levels than the index pathology. CONCLUSIONS: Multilevel minimally invasive spinal fixation is feasible in patients with diffuse spinal metastasis. The percutaneous nature of the technique minimizes dissection, blood loss, and operative times. Early outcomes of MIPSF are promising and demonstrate utility in avoiding multiple subsequent procedures in a cohort of deconditioned patients.

Pseudarthrosis Following Lumbar and Lumbosacral Fusion Using the Antepsoas Technique.

STUDY DESIGN: Retrospective case-control study. OBJECTIVE: The aim of this study was to evaluate the prevalence of pseudarthrosis following antepsoas (ATP) lumbar and lumbosacral fusions. SUMMARY OF BACKGROUND DATA: Pseudarthrosis is a feared complication following spinal fusions and may affect their clinical outcomes. To date there are no sufficient data on the fusion rate following ATP lumbar and lumbosacral arthrodesis. METHODS: This is a retrospective review of 220 patients who underwent lumbar minimally invasive antepsoas (MIS-ATP) fusions between January 2008 and February 2019 who have at least 1-year postoperative computed tomography (CT) follow-up scans. Fusion was graded using CT scans imaging and adopting a 1-4 grading scale (1, definitely fused; 2, likely fused; 3, likely not fused; 4, definitely not fused/nonunion). Grades 3 or 4 indicate pseudarthrosis. RESULTS: A total of 220 patients (average age: 66 years, 82 males (37.2%), and 127 (57.7%) smokers) were included. Eight patients (3.6%) developed pseudarthrosis. A total of 693 discs were addressed using the ATP approach. Of those, 681 (98.3%) were considered fused (641 levels [92.5%] were "definitely fused" and 40 levels [5.8%] were "Likely fused") and 12 discs (1.7%) developed pseudarthrosis (seven levels [1.0%] were "likely not fused" and five levels (0.7%) were "definitely not fused"). The highest rate of pseudarthrosis was found at L5-S1 (4.8%) compared to the L1-L5 discs (0-2%). Of 127 smokers, six developed pseudarthrosis (odds ratio = 2.3, P = 0.3). The fusion rates were 95.3% and 97.8% for smokers and nonsmokers, respectively. Of the eight patients who developed pseudarthrosis, only four (50%) were symptomatic, of whom two (25%) required revision surgery. Both of these patients were smokers. The overall revision rate due to pseudarthrosis was 0.9% (two of 220 patients). CONCLUSION: The MIS-ATP technique results in a high fusion rate (96.4% of patients; 98.3% of levels). Pseudarthrosis was noted mostly at the L5-S1 discs and in smokers.Level of Evidence: 4.