Gout As a Predictor of Total Knee Arthroplasty Outcomes and Costs.

Gout is the most common inflammatory arthritis and affects approximately 4% of the U.S. population. As the prevalence of gout and the number of total knee arthroplasties (TKAs) performed continue to increase, the literature on TKA in patients with gout remains scant. The purpose of this study was to evaluate the outcomes of patients with gout following TKA at a population level, that is, how patient with gout fair after TKA. We hypothesized that patients with gout have higher rates of complications and higher costs compared with controls. A case-control study was designed to evaluate two cohorts of Medicare patients who underwent TKA whose only distinguishing feature was the presence or absence of gout. Matching was performed to decrease confounding at a 1:1 ratio based on age, gender, and Charlson comorbidity index (CCI), (10-year survival predictor). The Medicare standard analytical files were queried through International Classification of Disease and current procedural terminology codes. A total of 15,238 patients were evaluated with 7,619 in each cohort. There were no age, gender, or CCI differences and 57.4% were females. Day of surgery and 90-day post-surgery costs were both significantly greater in those with gout (p < 0.001 for both). Multivariate analysis revealed that gout patients had increased odds of infection (odds ratio [OR] 1.229, p = 0.019), cardiac arrest (OR 1.354, p = 0.002), pneumonia (OR 1.161, p < 0.001), hematoma (OR 1.204, p = 0.002), and development of capsulitis (OR 1.208, p = 0.012). Nonetheless these patients had a decreased risk of pulmonary emboli (OR 0.835, p = 0.016). Our results support our hypothesis that patients with gout have higher rates of postoperative complications and increased day of surgery and 90-day costs of care after TKA. Given the high prevalence of gout in the United States, additional study on the utility of preoperative gout optimization for TKA patients is warranted. The level of evidence of this study is III, and it is a retrospective case-control study.

Pharmacologic Recruitment of Endogenous Neural Stem/Progenitor Cells for the Treatment of Spinal Cord Injury.

STUDY DESIGN: Laboratory study using a rat T9 contusion model of spinal cord injury. OBJECTIVE: This study aims to examine whether a combinatory treatment of Pioglitazone (PGZ) and granulocyte colony-stimulating factor (GCSF) can support neural stem/progenitor cells (NSPCs) directly and provide a sustainable microenvironment through immunomodulatory mechanisms. SUMMARY OF BACKGROUND DATA: Neuroinflammation plays a crucial role in the progression of spinal cord injury (SCI) and hinders NSPC-mediated repair and regeneration. Broad acting drugs that mitigate inflammation and support NSPC proliferation have not been tested together in SCI research models. METHODS: Isolated NSPCs were treated with vehicle control, PGZ, GCSF, or both PGZ and GSCF for 24 hours and stained with proliferation marker Ki67. Adult female Sprague-Dawley rats sustained moderate-to-severe contusion-based SCI at T9 and were administered either vehicle control, PGZ, GCSF, or both PGZ and GCSF treatments. RESULTS: Immunocytochemistry revealed that cultured NSPCs treated with both drugs produced higher numbers of actively proliferating cells and total cell numbers. ELISA on spinal cord tissue lysates at 1, 3, and 7 days post-injury (DPI) demonstrated that animals treated with PGZ, GCSF, or combination therapy showed significantly higher doublecortin levels at 7 DPI compared to control animals (P < 0.05). Immunohistochemistry of injured tissue at 3, 7, and 14 DPI revealed no difference of ependymal NSPC proliferation between groups, but showed a significant decrease in lesion size with combination therapy compared to controls. Functional recovery was assessed by the Basso, Beattie, Bresnahan locomotor rating scale. Animals treated with both drugs had significantly higher levels of function at 1 (P < 0.001), 3 (P < 0.001), 7 (P < 0.05), and 14 (P < 0.05) DPI compared to controls. CONCLUSION: These results indicate that PGZ and GCSF treatment synergistically enhance NSPCs numbers and improve functional recovery after SCI. Our findings support an immunomodulatory strategy to recruit native NSPCs as a potential acute care intervention for SCI.Level of Evidence: N/A.

Post-operative Outcomes and Survivorship for Shoulder Arthroplasty following Glenohumeral Tumor Resection.

A paucity of data exists for post-operative complications and survivorship in patients undergoing resection arthroplasty procedures for treatment of glenohumeral tumors. This study investigates patient and tumor characteristics, 90-day and long-term post-operative complications, and overall survivorship following glenohumeral tumor resection arthroplasty procedures. This single-center retrospective review identified 13 patients, with mean age of 51.6 ± 15.7 years, mean body mass index of 26.5 ± 6.4 kg/m2, and mean Charlson Comorbidity Index of 4.9 ± 2.4, who underwent shoulder arthroplasty procedures for glenohumeral tumors, most commonly for chondrosarcoma (n = 5) and metastatic disease (n = 3). Nine patients (69.2%) underwent revision surgeries at a median of 677 days, most commonly for prosthesis instability, dislocation (n=4) or aseptic loosening (n = 3). Seven patients (53.8%) were deceased at a median of 593.6 days. Resection arthroplasty in the treatment of glenohumeral tumors demonstrates low rates of complications during the global period but are fraught with long-term complications. This data provides pertinent information to pre-operatively counsel patients on post-operative expectations. (Journal of Surgical Orthopaedic Advances 31(4):248-251, 2022).

Keratin Biomaterials Improve Functional Recovery in a Rat Spinal Cord Injury Model.

STUDY DESIGN: Laboratory study using a rat T9 contusion model of spinal cord injury (SCI). OBJECTIVE: The purpose of this study was to evaluate which method of delivery of soluble keratin biomaterials would best support functional restoration through the macrophage polarization paradigm. SUMMARY OF BACKGROUND DATA: SCI is a devastating neurologic event with complex pathophysiological mechanisms that currently has no cure. After injury, macrophages and resident microglia are key regulators of inflammation and tissue repair exhibiting phenotypic and functional plasticity. Keratin biomaterials have been demonstrated to influence macrophage polarization and promote the M2 anti-inflammatory phenotype that attenuates inflammatory responses. METHODS: Anesthetized female Lewis rats were subjected to moderate T9 contusion SCI and randomly divided into: no therapy (control group), an intrathecally injected keratin group, and a keratin-soaked sponge group (n = 11 in all groups). Functional recovery assessments were obtained at 3- and 6-weeks post-injury (WPI) using gait analysis performed with the DigiGait Imaging System treadmill and at 1, 3, 7, 14, 21, 28, 35, and 42 days post-injury by the Basso, Beattie, Bresnahan (BBB) locomotor rating scale. Histology and immunohistochemistry of serial spinal cord sections were performed to assess injury severity and treatment efficacy. RESULTS: Compared to control rats, applying keratin materials after injury improved functional recovery in certain gait parameters and overall trended toward significance in BBB scores; however, no significant differences were observed with tissue analysis between groups at 6 WPI. CONCLUSION: Results suggest that keratin biomaterials support some locomotor functional recovery and may alter the acute inflammatory response by inducing macrophage polarization following SCI. This therapy warrants further investigation into treatment of SCI.Level of Evidence: N/A.

Clinical presentation, imaging findings, and arthroscopic features in skeletally immature and mature adolescent hip patients: a comparative double-cohort retrospective study.

The purpose of this study was to evaluate differences in clinical presentation and extent of surgery required based on skeletal maturity between two cohorts of adolescent hip arthroscopy patients. We hypothesized that skeletal immaturity would be associated with a lower frequency of pincer impingement and a decreased need for surgical acetabuloplasty. A database of 1481 hip arthroscopies performed by a single orthopaedic surgeon between 2008 and 2016 was queried. Patients ≤18 years of age with femoroacetabular impingement were divided into two groups based on Risser score: Risser 1-4 (skeletally immature) or Risser 5 (skeletally mature). Groups were compared with respect to presentation, diagnosis, and arthroscopic procedures performed. Eighty-eight skeletally immature and 49 skeletally mature patients were included. Mixed impingement was more common in skeletally mature patients than immature (67.3% vs. 48.9%, P = 0.037). Skeletal maturity was associated with a significantly increased probability of undergoing acetabuloplasty (odds ratio = 4.6, 95% confidence interval 1.4-15.5; P = 0.014). Extent of chondral degeneration was similar between groups. Our findings support the hypothesis that skeletally immature hips undergo acetabuloplasty less frequently and demonstrate similar chondromalacia compared with a skeletally mature cohort. These results suggest that arthroscopic treatment for impingement-associated hip pain may be a reasonable option to consider for symptomatic skeletally immature patients who have completed a structured course of nonoperative treatment. Additional longitudinal outcomes data are needed to clarify the natural history of impingement-associated hip pain in younger populations and whether hip arthroscopy delays progression of osteoarthritis in these patients.

The modified anterior ellipsoidal cap titanium cable tension band for comminuted patellar fractures.

PURPOSE: The purpose of this study was to assess the outcomes in a series of patients, who underwent cerclage and figure-of-eight tension band wiring using a single titanium cable for comminuted patellar fractures. METHODS: We describe a modified tension band technique using a single titanium cable to create an ellipsoidal cap structure that combines the circumferential and figure-of-eight wrapping in the fixation of closed Association for the Study of Internal Fixation/Orthopaedic Trauma Association 34C2 and 34C3 patellar fractures. We retrospectively reviewed 25 patients (16 males and 9 females, mean age 54 years) who underwent the described fixation technique between 2015 and 2017. Postoperative function was evaluated using the Böstman score. RESULTS: At the mean follow-up of 25 months (range 17-39 months), the mean Böstman score was 27.3 ± 2.6 points (range 23-30). Eighteen patients (72%) had excellent results (score ≥28); seven patients (28%) had good results (score 20-27); and no patients had an unsatisfactory result (score < 20). All surgical incisions healed without major wound complications. Two patients reported minor complications (soft tissue irritation, cellulitis). No patients demonstrated loss of reduction or implant failure during the follow-up period. CONCLUSION: The modified anterior ellipsoidal cap tension band using a single titanium cable created an effective tension band structure in the treatment of comminuted patella fractures. It is a simple operative technique that produced a stable fixation construct, which allowed early functional rehabilitation and weight-bearing with a high rate of excellent outcomes at 2 years after surgery.

Biomechanical Evaluation of Interfragmentary Compression of Lag Screw Versus Positional Screw at Different Angles of Fixation.

OBJECTIVES: To compare the compressive force achieved and retained with the lag versus positional screw technique at various angles of screw application. METHODS: Sixty humeral sawbones were stratified into 6 groups based on the technique (lag or positional) and fixation angle (30, 60, or 90 degrees relative to the fracture plane). A sensor was placed between fragments to record compressive force. Absolute screw force is the final screw force. Normalized force is the final screw force minus force generated by reduction forceps. Retained force is the quotient of absolute force relative to reduction forceps force. RESULTS: Lag screws attained higher force than positional at 60 degrees (absolute force 41% higher, P = 0.041; normalized force 1300% higher, P = 0.008; retained force 60% higher, P = 0.008) and 90 degrees (absolute force 86% higher, P = 0.006; normalized force 730% higher, P = 0.005; retained force 70% higher, P = 0.011), but not at 30 degrees. For lag screws, compressive force was similar at 60 and 90 degrees (absolute force P = 0.174, normalized force P = 0.364, and retained force P = 0.496), but not 30 degrees. For positional screws, no difference was found between the 3 angles of fixation for absolute force (P = 0.059). Normalized force and retained force were similar at 60 and 90 degrees (P = 0.944 and P = 0.725, respectively), but not 30 degrees. CONCLUSIONS: Lag screw technique compressive force was superior to positional screw technique at 60 and 90 degrees. Comparison of force at angles of 60 and 90 degrees showed no significant difference for both techniques. Indicating 30 degrees deviation from perfect technique is tolerated without significant decrease in compressive force.

Evaluation of Percutaneous Intradiscal Amniotic Suspension Allograft in a Rabbit Model of Intervertebral Disc Degeneration.

STUDY DESIGN: A laboratory study using a rabbit annular puncture model of intervertebral disc degeneration (IDD). OBJECTIVE: The aims of this study were to assess whether an amniotic suspension allograft (ASA) containing particulated human amnion and amniotic fluid derived cells regains intervertebral disc height and morphology and improves histologic scoring in a rabbit model of IDD. SUMMARY OF BACKGROUND DATA: In contrast to current surgical interventions for IDD, in which the primary goal is to relieve symptomatic pain, one novel strategy involves the direct injection of anabolic cytokines. Current therapies for IDD are limited by both the short half-life of therapeutic proteins and general decline in anabolic cell populations. METHODS: Intervertebral discs in New Zealand white rabbits were punctured using 18-gauge needle under fluoroscopic guidance. Four weeks post-puncture, two groups of rabbits were injected with either ASA or a vehicle/sham control, while a third group was untreated. Weekly radiographs were obtained for 12 weeks to assess disc height index (DHI). Magnetic resonance imaging (MRI) T2 relaxation time was evaluated at weeks 4 and 12 to assess morphological changes. Histologic sections were evaluated on a semi-quantitative grading scale. RESULTS: Before treatment at week 4, DHIs and normalized T2 relaxation times between the three groups were not significantly different. At week 12, ASA-treated rabbits exhibited significantly greater DHIs and MRI T2 relaxation times than vehicle and untreated control groups. The ASA group had higher mean histologic score than the vehicle group, which demonstrated extensive fiber disorganization and delamination with reduced proteoglycan staining on histology. CONCLUSION: Minimally invasive intervention with intradiscal injection of ASA was successful in reducing IDD in a reproducible rabbit model, with significant improvement in disc height and morphology when compared with vehicle and untreated control groups on radiographic and MRI analyses. LEVEL OF EVIDENCE: N/A.

Short-term safety and effectiveness of a second-generation motion-guided total knee system.

BACKGROUND: Modern knee prostheses are designed to more closely replicate normal knee kinematics. The JOURNEY II Bi-Cruciate Stabilized Total Knee System (Smith & Nephew Inc., Memphis, TN) is a second-generation motion-guided knee system that demonstrates axial rotation patterns during flexion, which resemble those of the normal knee. The aim of this study was to assess the short-term safety and effectiveness of this system in standard clinical practice. METHODS: A total of 186 subjects (209 primary total knee arthroplasties [TKAs]) were enrolled at 12 U.S. sites. Subjects were operated on between December 2011 and October 2013 and followed for 24 months. Radiographic, clinical, and patient-reported outcome data were collected at 6-, 12-, and 24-month postoperatively. RESULTS: At 24-month follow-up, the average objective Knee Society Score was 96.20 (standard deviation [SD] = 6.63), the average satisfaction score was 35.22 (SD = 6.63), the average expectation score was 10.91 (SD = 3.16), and the average functional activities score was 81.49 (SD = 14.65). On a 0-10 scale, pain level for walking was 0.79 (SD = 1.51) and 1.50 (SD = 1.97) for climbing stairs or inclines. The cumulative incidence of reoperation at 2-year follow-up was 1.48% (95% confidence interval [CI] 0.48%-4.52%). Ten TKAs in 7 patients were treated with closed manipulations for stiffness. Iliotibial band syndrome was reported in 2 TKAs. Two deep infections occurred, 1 requiring reoperation. No dislocations occurred in the study cohort. CONCLUSIONS: In short-term follow-up, the JOURNEY II Bi-Cruciate Stabilized Guided Motion Total Knee System appears to be a safe and effective device for TKA.

Ascorbic Acid and Its Clinical Role in Orthopaedic Surgery.

Ascorbic acid (vitamin C) is an essential micronutrient with evidence supporting its role in bone formation, tissue repair, and collagen production. Its clinical importance to the field of orthopaedic surgery has yet to be fully defined. Several observational studies have shown improved bone density and reduced hip fracture risk with supplementation. Its effect on bone fracture and soft tissue injury has been promising in animal models, but is not adequately studied in human trials. Results have been mixed concerning its role in chondroprotection and osteoarthritis treatment. Evidence suggesting reduced incidence of complex regional pain syndrome following distal radius fracture when treated with adjuvant ascorbic acid has prompted much debate but has received an endorsement of moderate support from the American Academy of Orthopaedic Surgeons. Given its potential benefits, low cost, and safety profile, ascorbic acid supplementation warrants consideration by orthopaedic surgeons in the treatment of a variety of musculoskeletal injuries (Journal of Surgical Orthopaedic Advances 27(4):261-268, 2018).

A chronically-denervated versus a freshly-harvested autograft for nerve repair in rats.

OBJECTIVES: Autologous nerve grafting remains the gold standard for repair of peripheral nerve injuries. Its use, however, is limited by donor nerve availability and donor site morbidity. This is especially problematic after failure of an initial autograft that requires a repeat nerve graft, resulting in a second surgical site with associated morbidity. Based on the molecular differences in nerve degeneration in the proximal and distal segments after transection, we hypothesized that a chronically-denervated proximal stump may be viable for autologous nerve repair. METHODS: 20 Sprague-Dawley rats underwent right sciatic nerve excision and sural nerve transection. After 8 weeks, nerve repair was performed by harvesting the proximal segment of the sural nerve (n=10) or a fresh sural nerve (n=10) from the contralateral hind limb. Electrophysiological changes were analyzed to compare the fresh and denervated grafts. RESULTS: Electrophysiological testing demonstrated higher compound motor action potential in the denervated group compared to the fresh autograft group, however this difference was not statistically significant (p=0.117). CONCLUSION: The proximal segment of a chronically-denervated sural nerve can be as effective as a fresh sural nerve for autologous repair of peripheral nerve injuries in a rodent model.