Journal of Bone and Joint Surgery, American Volume最新文献

Background: The aims of this study were to evaluate the timing and trend of venous thromboembolism (VTE) prophylaxis initiation following surgical intervention, and the impact of VTE prophylaxis timing on the occurrence of VTE complications, across North American trauma centers in patients with complete traumatic cervical spinal cord injury (SCI).

Methods: This retrospective, observational cohort study utilized data from the American College of Surgeons (ACS) Trauma Quality Improvement Program (TQIP) from 2013 to 2020. We identified surgically treated patients with complete traumatic cervical SCI. Patient variables included age, sex, race, insurance coverage, and comorbidity status. Outcomes of interest included time to VTE prophylaxis following surgery and the occurrence of VTE complications. Mixed-effect regression models were constructed to evaluate the adjusted estimate for each outcome accounting for patient-, injury-, and hospital-level covariates.

Results: The study included 5,325 patients treated across 463 trauma centers. The mean age in the cohort was 46.7 ± 18.9 years, with male predominance (81.1%). Race was predominantly White (62.3%) and Black (23.0%). The mean time to VTE prophylaxis initiation was 90 ± 112 hours, and the median time was 65 hours (interquartile range, 39 to 105 hours). The annual trend of VTE prophylaxis initiation after surgery was a decrease by 5.2 hours per year over the 8-year study interval. This was associated with an annual reduction of 6.2% in the odds of VTE complication occurrence. Multivariable mixed-effect regression models demonstrated a significant reduction in time to VTE prophylaxis (mean difference, -3.7 hours per year [95% confidence interval [CI], -5.3 to -2.1 hours per year]; p < 0.001) and VTE complications (odds ratio, 0.93 per year [95% CI, 0.88 to 0.98 per year]; p = 0.01) over the study period, after adjustment.

Conclusions: This analysis provides insight into VTE prophylaxis practice patterns following surgery for complete cervical SCI across North American trauma centers from 2013 to 2020. The timing of VTE prophylaxis initiation consistently decreased, which appeared to be associated with a significant reduction found in VTE complications.

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

➢ Humeral head anatomy affects the tension and mechanics of the glenohumeral joint. Thus, aiming for anatomic reconstruction can help to avoid negative consequences of component malpositioning (such as "overstuffing") on soft-tissue tension and impingement-free range of motion.➢ The most common method to assess humeral head reconstruction is comparing the prosthetic humeral articular surface with the "perfect circle" incorporating the lateral cortex of the greater tuberosity, the medial greater tuberosity, and the medial calcar at the anatomic neck. Although this method is quick and helpful in assessing multiple parameters, it is important to also compare the radius of curvature, assess traditional measurements of humeral head anatomy or glenohumeral thickness, and consider that non-anatomic sizing may be used to achieve tension goals.➢ There is no consistent evidence of superior humeral head reconstruction quality with stemless, short-stem, or standard-length humeral components, suggesting that surgical technique and familiarity with an implant system remain most important.➢ Although stemless and short-stem components offer versatility in recreating pre-arthritic anatomy, their use places emphasis on having a reproducible technique for humeral neck osteotomy depth and inclination. Some techniques include careful osteophyte resection to visualize the true anatomic neck, the use of an intramedullary guide, and intraoperative assessment with fluoroscopy.➢ Although small deviations from pre-arthritic anatomy do not appear to affect clinical outcome, center-of-rotation deviations of exceeding 3 to 4 mm from the perfect circle have been associated with an inferior clinical outcome.

Background: Patients who have undergone corrective surgery for adolescent idiopathic scoliosis (AIS), especially those with a major lumbar curve, may have persistent postoperative coronal imbalance (PCI) due to an insufficient ability to compensate for lumbar curve overcorrection. However, the optimal amount of curve correction required to prevent PCI remains uncertain. Therefore, this study aimed to evaluate the use of the intraoperative crossbar coronal-balancing technique as a strategy to minimize the risk of PCI in patients with AIS with a major lumbar curve (Lenke type-5 and 6 curves), and to confirm that the tilt angle of the lowest instrumented vertebra (LIV), intraoperatively and at the final follow-up, could be predicted from the preoperative supine right-side-bending (RSB) radiograph that was used to guide the correction.

Methods: This study involved 39 patients with Lenke 5 or 6 AIS who underwent posterior spinal fusion and had a minimum 2-year follow-up. The median age was 14 years, 15% were male, and all were of Malaysian ethnicity: 84.6% Chinese, 12.8% Malay, and 2.6% Indian. The LIV tilt angle measured on the preoperative supine RSB radiograph, adjusted according to the pelvic obliquity (PO) measured on the erect radiograph (α angle), was used as a guide for the intraoperative LIV tilt angle (β angle). Following curve correction, the crossbar was centered over the sacrum intraoperatively. The position of the C7 vertebra was then assessed relative to the crossbar, and the amount of correction was adjusted to ensure that the proximal portion of the crossbar bisected the C7 vertebra under fluoroscopy. Outcomes included the coronal balance distance (CBD) and the LIV tilt angle at the final follow-up (δ angle).

Results: Only 2 (5.1%) of the patients in the cohort had PCI at the final follow-up. At that time, the mean CBD was -6.6 ± 9.2 mm and the mean δ angle was -12.4° ± 4.8°. There were no significant differences between the α and β angles (p = 0.799) or between the α and δ angles (p = 0.705). The α angle correlated strongly with the β angle (ρ = 0.707) and the δ angle (ρ = 0.730, p < 0.001).

Conclusions: The intraoperative crossbar coronal-balancing technique was shown to be an effective method to minimize the risk of PCI in patients with AIS with a major lumbar curve. Guided by the α angle measured preoperatively, this approach may help facilitate the determination of the optimal intraoperative LIV tilt angle (β), which corresponds to the LIV tilt angle at the final folow-up (δ).

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

Background: Wear debris is a known contributor to orthopaedic implant failure, particularly in joint arthroplasty. The wear characteristics of spinal total disc replacement (TDR) remain under-investigated. Spinal TDRs have been shown to produce wear particles that elicit strong inflammatory reactions. Submicron debris, in particular, is associated with osteolysis and implant loosening. Viscoelastic TDR (VTDR) devices have emerged to address these risks.

Methods: Five AxioMed Freedom Lumbar Disc (FLD) devices underwent 30 million cycles (10 million each in flexion-extension, lateral bending, and axial rotation) of wear testing in phosphate-buffered saline solution at 37°C using an MTS servohydraulic system. Wear fluid samples were collected every 5 million cycles and analyzed using scanning electron microscopy and laser diffraction. A 30-million device cycle count simulates 240 years of lumbar bending. Wear rates were calculated in milligrams per million cycles (mg/MC). Comparative data for CHARITÉ (DePuy Synthes) and prodisc L (Centinel Spine) discs were obtained from the United States Food and Drug Administration (FDA) Summary of Safety and Effectiveness Data.

Results: The AxioMed device showed a mean wear rate of 1.7 mg/MC, in comparison to 5.7 mg/MC for the prodisc L. The number-average particle diameter was 1.9 μm, with a mass-average particle diameter of 49 μm, which was notably larger than those reportedly produced by the CHARITÉ (0.2 μm) and prodisc L (0.4 μm) devices, which is promising because larger particles (>1.0 μm) are less likely to induce inflammatory responses. No mechanical failures were observed during the 30 million cycles.

Conclusions: The AxioMed 1-piece VTDR device demonstrated a lower wear rate and larger, less biologically reactive, particles compared with articulating TDRs, suggesting a reduced risk of osteolysis and longer implant lifespan. No mechanical failures were observed, even after each 10-million-cycle interval, which simulates approximately 80 years of lumbar-bending motions. This study focused on particle size; further work is warranted to characterize composition and particle burden.

Clinical relevance: This 1-piece VTDR may offer a safer and more durable alternative for motion-preserving lumbar spine surgery. Further clinical and retrieval studies are warranted.