Suspected gluteal compartment syndrome: Etiology predicts clinical course, outcomes and resource utilization.

Background: Gluteal Compartment Syndrome (GCS) is a rare subtype of acute compartment syndrome (ACS), complex to diagnose and potentially fatal if left untreated. The incidence of ACS is estimated to be 7.3 per 100,000 in males and 0.7 per 100,000 in females [1-3]. Given its rare occurrence, the incidence of GCS is not well reported. In the case of GCS, the most common etiologies are surgical positioning, prolonged immobilization secondary to substance use or loss of consciousness, and traumatic injury. Clinical findings are pulselessness, pallor, parasthesia, paralysis, and most notably pain out of proportion. Swift diagnosis and treatment are imperative to reduce morbidity and mortality, however the ideal management of GCS is difficult to ascertain given the rare occurrence and variable presentation. Methods: Orthopaedic trauma database at a level 1 trauma center was reviewed to identify patients for whom the orthopaedic service was consulted due to suspicion of gluteal compartment syndrome. This yielded 11 patients between 2011 and 2019. Patients with a measured ΔP greater than 30 upon initial consultation and with a concerning exam requiring monitoring were included. Patient demographics, comorbidities, GCS etiology, laboratory values, physical exam findings, pain scores (0-10) and patient outcomes were collected via chart review. Patient demographic and injury characteristics were summarized using descriptive statistics. Results: Prolonged immobilization patients had worse outcomes including longer hospital stays (40.5 days) compared to trauma patients (4.5 days). All adverse medical outcomes recorded including acute renal failure, prolonged neuropathic pain, cardiopulmonary dysfunction were exclusively experienced by prolonged immobilization patients. Conclusions: Our descriptive study demonstrates the bimodal distribution of GCS patients based on etiology. Prolonged immobilization patients have a longer hospital course and more complications. Our study confirms prior reports and provides information that can be used to counsel patients and families appropriately about treatment and recovery following GCS. Level of evidence: IV. Study type: Epidemiological.

Outcomes of the Latarjet procedure in female patients: A case series and matched-pair analysis.

Background: The objective of this study was to retrospectively report on the outcomes of female patients undergoing the Latarjet procedure. Methods: Female patients undergoing the Latarjet procedure with minimum 1 year follow-up were identified and contacted to obtain Numeric Pain Rating Scale (NPRS), Subjective Shoulder Value (SSV), and return to sport (RTS) data. Eligible females were then matched 1:1 with a male counterpart based on laterality and age (± 3 years), and outcomes compared. Results: A total of 20 female patients with a mean follow-up of 73.8 months reported postoperative NPRS and SSV scores of 2.2 ± 2.3 and 69.3 ± 22.0, respectively. Of the nine athletes, 3 (33%) reported a successful RTS at a mean of 9 months. Four patients (20.0%) required reoperation at a mean of 27.1 months. The matched analysis demonstrated similar NPRS scores between male and female patients and a trend towards lower SSV scores and rates of RTS. Conclusion: At mid-term follow-up female patients reported pain levels similar to female-specific literature reports, but overall low subjective shoulder function and RTS. Compared to propensity-matched males, females reported similar levels of pain, lower shoulder function, and lower rates of RTS, however, differences did not reach statistical significance. Level of Evidence: IV, retrospective case series.

Clinical and radiographic outcomes of the modified McLaughlin procedure for locked posterior dislocation of the shoulder: a systematic review.

Background: Multiple treatment options for locked posterior dislocation of the shoulder (LPDS) have been described, including the modified McLaughlin procedure. The purpose of this review, therefore, was to perform a systematic review of the literature to synthesize the available data reporting on the clinical and radiographic outcomes of patients undergoing the modified McLaughlin procedure for the treatment of LPDS. Methods: A systematic review of the PubMed Central, MEDLINE, Embase, Scopus, Web of Science, and Cochrane Library databases from inception through January 2023 was performed. Outcomes studies reporting on clinical and radiographic outcomes in patients undergoing the modified McLaughlin procedure for LPDS were included. Postoperative complications and episodes of recurrent instability were noted. Results: A total of 1322 studies were initially identified, of which 9 were deemed eligible for inclusion in our review. Among included studies, a total of 97 shoulders (96 patients) with a mean age of 37.7 years (range, 26-51) were identified. The most common mechanisms of injury included trauma, seizure, and electrocution. Reverse Hill-Sachs lesions ranged in size from 20% to 50% of the humeral head articular surface. At final follow-up, the weighted mean University of California at Los Angeles shoulder score, Constant-Murley Score, American Shoulder and Elbow Surgeons shoulder score, and visual analog scale for pain score were 29 (range, 27-31), 75 (range, 65-92), 92 (range, 83-98), and 1.9 (range, 1-2.4), respectively. Postoperative Constant-Murley Score and University of California at Los Angeles scores were highest in the one study reporting exclusively on treatment during the acute period. Weighted mean postoperative forward flexion, abduction, external rotation, and internal rotation were 154° (range, 102-176), 144° (range, 118-171), 64° (range, 44-84), and 47° (range, 42-56), respectively. Osteointegration of the lesser tuberosity was noted in all patients at the final follow-up. Postoperative complications occurred in one patient (1.0% of cohort); a screw migration successfully treated with operative removal. Recurrent instability was noted in two epileptic patients (2.1% of cohort). Conclusion: The literature surrounding the use of the modified McLaughlin procedure for LPDS remains sparse. This review demonstrates that this procedure is associated with favorable clinical and radiographic outcomes with overall low rates of complication and recurrent instability, especially when the time from injury to surgery is minimized. These findings illustrate that in patients presenting with LPDS and a reverse Hill-Sachs lesion between 20% and 50% of the humeral head articular surface, the modified McLaughlin procedure is a safe and effective treatment option.

Outcomes of Humerus Nonunion Surgery in Patients With Initial Operative Fracture Fixation.

OBJECTIVES: To describe outcomes following humerus aseptic nonunion surgery in patients whose initial fracture was treated operatively and to identify risk factors for nonunion surgery failure in the same population. DESIGN: Retrospective case series. SETTING: Eight, academic, level 1 trauma centers. PATIENTS SELECTION CRITERIA: Patients with aseptic humerus nonunion (OTA/AO 11 and 12) after the initial operative management between 1998 and 2019. OUTCOME MEASURES AND COMPARISONS: Success rate of nonunion surgery. RESULTS: Ninety patients were included (56% female; median age 50 years; mean follow-up 21.2 months). Of 90 aseptic humerus nonunions, 71 (78.9%) united following nonunion surgery. Thirty patients (33.3%) experienced 1 or more postoperative complications, including infection, failure of fixation, and readmission. Multivariate analysis found that not performing revision internal fixation during nonunion surgery (n = 8; P = 0.002) and postoperative de novo infection (n = 9; P = 0.005) were associated with an increased risk of recalcitrant nonunion. Patient smoking status and the use of bone graft were not associated with differences in the nonunion repair success rate. CONCLUSIONS: This series of previously operated aseptic humerus nonunions found that more than 1 in 5 patients failed nonunion repair. De novo postoperative infection and failure to perform revision internal fixation during nonunion surgery were associated with recalcitrant nonunion. Smoking and use of bone graft did not influence the success rate of nonunion surgery. These findings can be used to give patients a realistic expectation of results and complications following humerus nonunion surgery. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Are Orthopaedic Trauma Surgeons Appropriately Compensated for Treating Acetabular Fractures? An Analysis of Operative Times and Relative Value Units.

OBJECTIVES: To evaluate the work relative value units (RVUs) attributed per minute of operative time (wRVU/min) in fixation of acetabular fractures, evaluate surgical factors that influence wRVU/min, and compare wRVU/min with other procedures. DESIGN: Retrospective. SETTING: Level 1 academic center. PATIENT SELECTION CRITERIA: Two hundred fifty-one operative acetabular fractures (62 A, B, C) from 2015 to 2021. OUTCOME MEASURES AND COMPARISONS: Work relative value unit per minute of operative time for each acetabular current procedural terminology (CPT) code. Surgical approach, patient positioning, total room time, and surgeon experience were collected. Comparison wRVU/min were collected from the literature. RESULTS: The mean wRVU per surgical minute for each CPT code was (1) CPT 27226 (isolated wall fracture): 0.091 wRVU/min, (2) CPT 27227 (isolated column or transverse fracture): 0.120 wRVU/min, and (3) CPT 27228 (associated fracture types): 0.120 wRVU/min. Of fractures with single approaches, anterior approaches generated the least wRVU/min (0.091 wRVU/min, P = 0.0001). Average nonsurgical room time was 82.1 minutes. Surgeon experience ranged from 3 to 26 years with operative time decreasing as surgeon experience increased ( P = 0.03). As a comparison, the wRVU/min for primary and revision hip arthroplasty have been reported as 0.26 and 0.249 wRVU/min, respectively. CONCLUSIONS: The wRVUs allocated per minute of operative time for acetabular fractures is less than half of other reported hip procedures and lowest for isolated wall fractures. There was a significant amount of nonsurgical room time that should be accounted for in compensation models. This information should be used to ensure that orthopaedic trauma surgeons are being appropriately supported for managing these fractures. LEVEL OF EVIDENCE: Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Outcomes After Hallux Interphalangeal Joint Arthrodesis.

BACKGROUND: Hallux interphalangeal joint arthrodesis (HIPJA) is indicated for a variety of pathologies. Despite high nonunion rates, techniques remain unchanged. The aim of this study is to examine nonunion and complication rates and describe risk factors for treatment failure. METHODS: A query of an institutional database was performed to identify all patients undergoing HIPJA procedure over a 10-year period. Records were reviewed to the procedure, evaluate patient factors, indications, and radiographic/clinical arthrodesis. Radiographic union was defined as 2 cortical continuations or bridging at the arthrodesis site, absence of hardware failure, and the absence of lytic gapping of the arthrodesis. Clinical fibrous union was defined as radiographic nonunion with painless toe range of motion and physical examination consistent with fusion across the interphalangeal joint. RESULTS: Two hundred twenty-seven primary HIPJA procedures were identified. Our cohort demonstrated a 25.5% nonunion rate (58/227) and 21.1% reoperation rate (48/227). Patients with diabetes were at higher risk for nonunion (P = .014), but no significant differences were identified based on smoking status or diagnosis of inflammatory arthritis. No difference was seen between implant groups: single screw, multiple screws, screw plus other fixation, nonscrew fixation. Patients with prior hallux metatarsophalangeal joint arthrodesis did not have a significantly higher nonunion rate than patients without prior first metatarsophalangeal joint arthrodesis. Patients diagnosed with radiographic nonunion were at higher risk for reoperation (P < .0001). CONCLUSION: Our cohort represents the largest single-center series of HIPJA procedures published to date. We found relatively high nonunion and reoperation rates with standard current techniques. LEVEL OF EVIDENCE: Level III, retrospective case series.

Orthopaedic Trauma Never Sleeps: Resource Allocation Even During a Non-trauma Crisis.

This study aimed to describe hospital resource utilization of an orthopaedic trauma service and the injury epidemiology during the 2019-2020 coronavirus pandemic to help plan future non-trauma crises. A retrospective chart review was performed on adult patients > 18 years of age who presented to our Level I Trauma Center for musculoskeletal trauma from March 30, 2020 to May 8, 2020 (stay-at-home order) and from March 30, 2019 to May 8, 2019 (comparison group). There were 182 patient encounters and 274 fractures in the 2020 stay-at-home period, and there were 210 patient encounters and 337 fractures in the 2019 control group. There was no statistical difference found comparing the proportion of patient encounters in the stay-at-home period to the control period (p > 0.05). The similar volume of consultations and surgeries justifies maintenance of standard resource allocation. (Journal of Surgical Orthopaedic Advances 32(2):102-106, 2023).

Opioid-Free Analgesia Provides Pain Control Following Thumb Carpometacarpal Joint Arthroplasty.

BACKGROUND: We hypothesized that an opioid-free (OF), multimodal pain management pathway for thumb carpometacarpal (CMC) joint arthroplasty would not have inferior pain control compared with that of a standard opioid-containing (OC) pathway. METHODS: This was a single-center, randomized controlled clinical trial of patients undergoing primary thumb CMC joint arthroplasty. Patients were randomly allocated to either a completely OF analgesic pathway or a standard OC analgesic pathway. Patients in both cohorts received a preoperative brachial plexus block utilizing 30 mL of 0.5% ropivacaine that was administered via ultrasound guidance. The OF group was given a combination of cryotherapy, anti-inflammatory medications, acetaminophen, and gabapentin. The OC group was only given cryotherapy and opioid-containing medication for analgesia. Patient-reported pain was assessed with use of a 0 to 10 numeric rating scale at 24 hours, 2 weeks, and 6 weeks postoperatively. We compared the demographics, opioid-related side effects, patient satisfaction, and Veterans RAND 12-Item Health Survey (VR-12) results between these 2 groups. RESULTS: At 24 hours postoperatively, pain scores in the OF group were statistically noninferior to, and lower than, those in the OC group (median, 2 versus 4; p = 0.008). Pain scores continued to differ significantly at 2 weeks postoperatively (median, 2 versus 4; p = 0.001) before becoming more similar at 6 weeks (p > 0.05). No difference was found between groups with respect to opioid-related side effects, patient satisfaction, or VR-12 results. CONCLUSIONS: A completely opioid-free perioperative protocol is effective for the treatment of pain following thumb CMC joint arthroplasty in properly selected patients. LEVEL OF EVIDENCE: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Thoracic Outlet Syndrome Secondary to Vascular Insufficiency from Congenital Pseudarthrosis of the Clavicle: A Case Report.

CASE: An 18-year-old woman with a history of congenital pseudarthrosis of the clavicle (CPC) presented with episodes of right upper extremity ischemia. Vascular studies demonstrated an extensive thrombus with complete occlusion of the brachial artery. She underwent urgent thrombectomy. Subsequently, she underwent first rib resection and scalenectomy as well as pseudarthrosis takedown and fixation. Postoperatively, she returned to Division I collegiate soccer with complete symptomatic resolution. CONCLUSION: We report a case of arterial thoracic outlet syndrome secondary to CPC.

Feasibility of Nerve Transfer to Palmaris Longus in Forearm-Level TMR: Anatomic Study and Clinical Series.

BACKGROUND: Targeted muscle re-innervation (TMR) is increasingly being used for treatment of postamputation pain and myoelectric prosthesis (MYP) control. Palmaris longus (PL) is a potential target following transradial amputation. The purpose of this study was to determine the branching pattern of the median nerve (MN) as it pertains to the PL motor branch entry point (MEP) and to present clinical results of patients who had PL used as a target. METHODS: Eight cadaveric arms were dissected and branching patterns of the MN were documented. Additionally, we reviewed adult patients from a prospectively collected database who underwent TMR using PL. We recorded patient-reported outcomes and signal strength generated by the PL. RESULTS: The average distance from the medial epicondyle to PL MEP was 53 mm. All palmaris motor branches passed through a chiasm within the flexor digitorum superficialis muscle belly, which was a mean of 18 mm away from the MN proper. Patients with long-term follow-up reported an average Pain visual analog scale of 3.3 and Disabilities of the Arm, Shoulder and Hand of 46.2. All but one patient were using an MYP, and all generated at least 10 mV of signal from the PL, which is ample signal for surface electrode detection and MYP control. There were no postoperative neuromas and only one patient-reported postoperative phantom limb pain. CONCLUSIONS: Palmaris longus is a suitable target for TMR. Our objective measurements and anatomic relationships may help surgeons consistently find the PL's motor branch. Our series of patients reveal sufficient signal strength and acceptable clinical outcomes following TMR using the PL.

Revision total elbow arthroplasty using intramedullary strut allograft for aseptic loosening of the humeral stem.

Total elbow arthroplasty (TEA) has become a well-accepted treatment option for many pathologies of the elbow joint. Its use in distal humerus fractures in elderly patients has become increasingly popular and has good clinical results. However, with the aging population and the increasing number of TEAs performed, so comes the potential for an increasing number of revision TEA cases. Revision TEA can be extremely challenging. In addition to the technical difficulties of safe exposure and implant removal, reimplantation of a cemented humeral component with loss of bone stock can be a challenging step in this procedure. The purpose of this article was to describe a novel technique to address aseptic loosening of the humeral stem and loss of humeral bone stock with revision of the humeral component using a long-stemmed cemented implant and intramedullary allograft fibular strut bone grafting.

Intraoperative and Early (90-Day) Postoperative Complications and Associated Variables with Multiligamentous Knee Reconstruction: 15-year Experience from a Single Academic Institution.

PURPOSE: We sought to determine the rate of intraoperative and early postoperative (90-day) complications of multiligamentous knee reconstruction surgeries, both medical and surgical, and associated variables from the 15-year experience of a single academic institution. METHODS: Patients treated at a single academic institution between 2005 and 2019 who underwent multiligament knee surgery were identified. Inclusion criteria included intervention with 2+ ligament reconstructions performed concurrently, and more than 90 days postoperative follow-up. Exclusion criteria included revision ligamentous knee surgery. Patient demographics, mechanism of injury, and associated injuries of patients with intraoperative and postoperative complications, time from injury to multiligamentous knee reconstruction, and surgical data, including tourniquet time, procedure time, and type of procedures performed were retrospectively recorded. RESULTS: 301 knees in 296 patients met the eligibility criteria. There were 11 intraoperative complications in 9 knees (rate of 3%) and 136 postoperative complications in 90 knees (rate of 30%). Shorter time from injury to date of surgery was associated with arthrofibrosis (P = .001) and superficial wound infections (P = .015). Concurrent head injuries were associated with less complications (P = .029). Procedural time >300 minutes was associated with intraoperative blood transfusions (P > .05), deep infections (P = .003) and arthrofibrosis (P = .012). Inside-out meniscal repair was associated with superficial and deep infections (P = .006 and .0004). Tibial-based posterolateral corner (PLC) reconstruction was associated with symptomatic hardware (P = .037) and arthrofibrosis (P = .019) in comparison with fibular-based PLC reconstruction. Posterior cruciate ligament (PCL) reconstruction was associated with deep infections (P = .015), arthrofibrosis (P = .003), and postoperative blood transfusions (P = .018). CONCLUSION: Our 15-year data reveal there is a low intraoperative complication rate and high early postoperative complication rate with multiligamentous knee surgery. Surgeons should be wary of the increased intraoperative and postoperative complications associated with longer procedure times, inside-out meniscal repair, tibia-based PLC reconstruction, PCL reconstruction, and shorter time to surgery. LEVEL OF EVIDENCE: Case series: IV.

Age and socioeconomic status affect access to telemedicine at an urban level 1 trauma center.

OBJECTIVES: Despite clinical and economic advantages, routine utilization of telemedicine remains uncommon. The purpose of this study was to examine potential disparities in access and utilization of telehealth services during the rapid transition to virtual clinic during the coronavirus pandemic. DESIGN: Retrospective chart review. SETTING: Outpatient visits (in-person, telephone, virtual-Doxy.me) over a 7-week period at a Level I Trauma Center orthopaedic clinic. INTERVENTION: Virtual visits utilizing the Doxy.me platform. MAIN OUTCOME MEASURES: Accessing at least 1 virtual visit ("Virtual") or having telephone or in-person visits only ("No virtual"). METHODS: All outpatient visits (in-person, telephone, virtual) during a 7-week period were tracked. At the end of the 7-week period, the electronic medical record was queried for each of the 641 patients who had a visit during this period for the following variables: gender, ethnicity, race, age, payer source, home zip code. Data were analyzed for both the total number of visits (n = 785) and the total number of unique patients (n = 641). Patients were identified as accessing at least 1 virtual visit ("Virtual") or having telephone or in-person visits only ("No virtual"). RESULTS: Weekly totals demonstrated a rapid increase from 0 to greater than 50% virtual visits by the third week of quarantine with sustained high rates of virtual visits throughout the study period. Hispanic and Black/African American patients were able to access virtual care at similar rates to White/Caucasian patients. Patients of ages 65 to 74 and 75+ accessed virtual care at lower rates than patients ≤64 (P = .003). No difference was found in rates of virtual care between payer sources. A statistically significant difference was found between patients from different zip codes (P = .028). CONCLUSION: A rapid transition to virtual clinic can be performed at a level 1 trauma center, and high rates of virtual visits can be maintained. However, disparities in access exist and need to be addressed.

Establishing a common language for lumbar transforaminal epidural steroid injections.

BACKGROUND: Patients presenting to spine surgeons for lumbar radiculopathy often undergo initial conservative treatment including medications, therapy, and lumbar transforaminal epidural steroid injections. Despite a growing number of spinal injections performed, there is a lack of available data regarding the occurrence of wrong-site injections. However, when examined, the discrepancies between ordering level and level of epidural steroid injection performed are immense. To aid with this issue, we propose that instead of ordering a lumbar transforaminal epidural steroid injections at a given level, it should be ordered to address a specific nerve root with laterality. This has the potential to reduce wrong-site procedures and improve patient outcomes. METHODS: Retrospective chart review of 60 patients at a private orthopaedic spine practice under the care of spine surgeons or physician assistants over a 1-year period. The progress note, injection order form, procedure note, and procedural fluoroscopy were reviewed. If there were inconsistencies between one or more of these steps, it was deemed a failure. Results were analyzed to assess for any differences in outcomes between the two groups. We calculated our sample size prior to the study and powered it at 90%; descriptive statistics, Chi-square, Fisher's exact test, Student's t-test, and Wilcoxon rank sum tests were used where appropriate utilizing SAS v9.4. RESULTS: Thirty-seven patients (37/60, 61.6%) were considered a failure. There were no failures when ordering an S1 nerve root injection. We identified one wrong-site procedure and one wrong-level order that was identified and corrected by the interventionalist. CONCLUSIONS: There were multiple inconsistencies identified at various steps in the injection ordering process. This indicates a need to standardize the language used in this process to avoid wrong-site procedures. There were no inconsistencies in ordering an S1 injection, likely because this injection could only be ordered at the nerve root. It is also critical to utilize and save a localization film to ensure accuracy and accountability. We propose indicating the affected nerve root in all cases rather than the level of disc pathology would avoid confusion.

Surgical Re-entry Strategy Following COVID-19 Pandemic: A Tiered and Balanced Approach.

Following the Presidential declaration of a national emergency, many health care organizations adhered to recommendations from the Centers for Medicare and Medicaid (CMS) as well as the American College of Surgeons (ACS) to postpone elective surgical cases. The transition to only emergent and essential urgent surgical cases raises the question, how and when will hospitals and surgery centers resume elective cases? As a large health care system providing multispecialty tertiary/quaternary care with across the Southeast United States, a collaborative approach to resuming elective surgery is critical. Numerous surgical societies have outlined a tiered approach to resuming elective surgery. The majority of these guidelines are suggestions which place the responsibility of making decisions about re-entry strategy on individual health care systems and practitioners, taking into account the local case burden, projected case surge, and availability of resources and personnel. This paper reviews challenges and solutions related to the resumption of elective surgeries and returning to the pre-COVID-19 surgical volume within an integrated health care system that actively manages 18 facilities, 111 operating rooms, and an annual operative volume exceeding 123,000 cases. We define the impact of COVID-19 across our surgical departments and outline the staged re-entry approach that is being taken to resume surgery within the health care system.

The Size of Intramedullary Fixation Affects Endochondral-Mediated Angiogenesis During Fracture Repair.

OBJECTIVES: To explore the effect of intramedullary pin size on the biology of a healing fracture, specifically endochondral angiogenesis. We hypothesized that fracture fixation with a smaller pin would permit greater interfragmentary strain resulting in increased total amount of vascular endothelial growth factor within the callus and greater angiogenesis compared to fixation with a larger pin. METHODS: Transverse mid-shaft femur fractures in 8-week-old mice were fixed with either a 23-gauge (G) or 30-G pin. Differences in interfragmentary strain at the fracture site were estimated between cohorts. A combination of histology, gene expression, serial radiography, and microcomputed tomography with and without vascular contrast agent were used to assess fracture healing and vascularity for each cohort. RESULTS: Larger soft-tissue callus formation increased vascular endothelial growth factor-A expression, and a corresponding increase in vascular volume was observed in the higher strain, 30-G cohort. Radiographic analysis demonstrated earlier hard callus formation with greater initial interfragmentary strain, similar rates of union between pin size cohorts, yet delayed callus remodeling in mice with the larger pin size. CONCLUSIONS: These findings suggest that the stability conferred by an intramedullary nail influences endochondral angiogenesis at the fracture.

The cost of hydrocephalus: a cost-effectiveness model for evaluating surgical techniques.

In BriefThe authors analyzed the costs associated with the three different procedures used to treat hydrocephalus in the pediatric population. They believe this study highlights the importance of patient-specific treatment decisions that are based on etiology and previous intervention. The patient-specific medical characteristics are a driving force in the cost of care.

Autologous chondrocyte grafting promotes bone formation in the posterolateral spine.

BACKGROUND CONTEXT: Pseudarthrosis following spinal fusion remains problematic despite modern surgical and grafting techniques. In surgical spinal fusion, new bone forms via intramembranous and endochondral ossification, with endochondral ossification occurring in the hypoxic zones of the fusion bed. During bone development and fracture healing, the key cellular mediator of endochondral ossification is the hypertrophic chondrocyte given its ability to function in hypoxia and induce neovascularization and ossification. We therefore hypothesize that hypertrophic chondrocytes may be an effective bone graft alternative. PURPOSE: Spinal fusion procedures have increased substantially; yet 5% to 35% of all spinal fusions may result in pseudoarthrosis. Pseudoarthrosis may occur because of implant failure, infection, or biological failure, among other reasons. Advances in surgical techniques and bone grafting have improved fusion; however pseudarthrosis rates remain unacceptably high. Thus, the goal of this study is to investigate hypertrophic chondrocytes as a potential biological graft alternative. METHODS: Using a validated murine fracture model, hypertrophic chondrocytes were harvested from fracture calluses and transplanted into the posterolateral spines of identical mice. New bone formation was assessed by X-ray, microcomputed tomography (µCT), and in vivo fluorescent imaging. Results were compared against a standard iliac crest bone graft and a sham surgery control group. Funding for this work was provided by the Department of Orthopaedics and Rehabilitation, the OREF (Grant #16-150), and The Caitlin Lovejoy Fund. RESULTS: Radiography, µCT, and in vivo fluorescent imaging demonstrated that hypertrophic chondrocytes promoted bone formation at rates equivalent to iliac crest autograft. Additionally, µCT analysis demonstrated similar fusion rates in a subset of mice from the iliac crest and hypertrophic chondrocyte groups. CONCLUSIONS: This proof-of-concept study indicates that hypertrophic chondrocytes can promote bone formation comparable to iliac crest bone graft. These findings provide the foundation for future studies to investigate the potential therapeutic use of hypertrophic chondrocytes in spinal fusion.

Bone Fracture Acute Phase Response-A Unifying Theory of Fracture Repair: Clinical and Scientific Implications.

Bone fractures create five problems that must be resolved: bleeding, risk of infection, hypoxia, disproportionate strain, and inability to bear weight. There have been enormous advancements in our understanding of the molecular mechanisms that resolve these problems after fractures, and in best clinical practices of repairing fractures. We put forth a modern, comprehensive model of fracture repair that synthesizes the literature on the biology and biomechanics of fracture repair to address the primary problems of fractures. This updated model is a framework for both fracture management and future studies aimed at understanding and treating this complex process. This model is based upon the fracture acute phase response (APR), which encompasses the molecular mechanisms that respond to injury. The APR is divided into sequential stages of "survival" and "repair." Early in convalescence, during "survival," bleeding and infection are resolved by collaborative efforts of the hemostatic and inflammatory pathways. Later, in "repair," avascular and biomechanically insufficient bone is replaced by a variable combination of intramembranous and endochondral ossification. Progression to repair cannot occur until survival has been ensured. A disproportionate APR-either insufficient or exuberant-leads to complications of survival (hemorrhage, thrombosis, systemic inflammatory response syndrome, infection, death) and/or repair (delayed- or non-union). The type of ossification utilized for fracture repair is dependent on the relative amounts of strain and vascularity in the fracture microenvironment, but any failure along this process can disrupt or delay fracture healing and result in a similar non-union. Therefore, incomplete understanding of the principles herein can result in mismanagement of fracture care or application of hardware that interferes with fracture repair. This unifying model of fracture repair not only informs clinicians how their interventions fit within the framework of normal biological healing but also instructs investigators about the critical variables and outputs to assess during a study of fracture repair.