Rapamycin Inhibits Senescence and Improves Immunomodulatory Function of Mesenchymal Stem Cells Through IL-8 and TGF-β Signaling

Mesenchymal stromal cells (MSCs) grown in high-density monolayers (sheets) are promising vehicles for numerous bioengineering applications. When MSC sheets are maintained in prolonged cultures, they undergo rapid senescence, limiting their downstream efficacy. Although rapamycin is a potential agent that can inhibit senescence in cell cultures, no study has investigated rapamycin's effect on MSCs grown in high-density culture and its effect on downstream target gene expression. In this study, placental-derived MSCs (PMSCs) were seeded at high density to generate PMSC sheets in 24 hours and were then treated with rapamycin or vehicle for up to 7 days. Autophagy activity, cell senescence and apoptosis, cell size and granularity, and senescence-associated cytokines (IL-6 and IL-8) were analyzed. Differential response in gene expression were assessed via microarray analysis. Rapamycin significantly increased PMSC sheet autophagy activity, inhibited cellular senescence, decreased cell size and granularity at all timepoints. Rapamycin also significantly decreased the number of cells in late apoptosis at day 7 of sheet culture, as well as caspase 3/7 activity at all timepoints. Notably, while rapamycin decreased IL-6 secretion, increased IL-8 levels were observed at all timepoints. Microarray analysis further confirmed the upregulation of IL-8 transcription, as well as provided a list of 396 genes with 2-fold differential expression, where transforming growth factor-β (TGF-β) signaling were identified as important upregulated pathways. Rapamycin both decreased senescence and has an immunomodulatory action of PMSCs grown in sheet culture, which will likely improve the chemotaxis of pro-healing cells to sites of tissue repair in future bioengineering applications.

Biomechanical Comparison of All-Suture, All-Inside Meniscus Repair Devices in a Human Cadaveric Meniscus Model

OBJECTIVE

Newer all-suture, all-inside meniscus repair devices utilize soft suture anchors. The purpose of this study was to compare the biomechanical performance of 4 meniscus repair devices in human cadaver menisci: the JuggerStitch (all-suture, all-inside), the FiberStitch (all-suture, all-inside), a polyether ether ketone (PEEK) all-inside, and an inside-out device.

DESIGN

Forty human cadaver menisci were tested after creating 20 mm longitudinal tears in the posterior meniscus. Each knee was randomized to 1 of 4 meniscus repair groups: JuggerStitch (all-suture, all-inside), FiberStitch (all-suture, all-inside), FAST-FIX 360 (PEEK-based anchor all-inside), and inside-out (with BroadbandTM tape meniscus needles). For each meniscus, 2 devices were used to prepare vertical mattress repair construct. The specimens were tested by pre-conditioning 20 cycles between 5 N and 30 N and then the tear diastasis was measured, followed by distraction to failure phase after imposing a displacement at a rate of 0.5 mm/s.

RESULTS

Ten menisci were tested in each of the 4 groups. After pre-conditioning, there was no significant difference in the gap formation among groups (P = 0.212). The average failure load for the JuggerStitch, FiberStitch, PEEK all-inside, and inside-out was 384 N, 311 N, 207 N, and 261 N, respectively, with a significant difference between groups (P = 0.034). Post hoc analysis showed the JuggerStitch failure load was higher than the PEEK all-inside and inside-out (P = 0.005, and P = 0.045, respectively). There was no significant difference between the failure load of the JuggerStitch and FiberStitch (P = 0.225).

CONCLUSION

The JuggerStitch all-suture device, FiberStitch all-suture device, PEEK all-inside, and inside-out devices have similar biomechanical properties for gapping and stiffness. The JuggerStitch all-suture, all-inside device has superior failure load compared with the PEEK all-inside and inside-out repair for longitudinal meniscus tear repair.

The Joystick Method: A Mini Open Technique for Repairing Patellar Osteochondral Fractures With Concomitant Medial Patellofemoral Ligament Reconstruction

Fixation of osteochondral fractures after patellar dislocation is typically done using an open approach due to the location of the defect. This is traditionally performed through a medial parapatellar arthrotomy to allow adequate visualization. By using the joystick method, adequate visualization is achieved with a smaller arthrotomy. Careful placement of the joystick in the planned anchor site of the medial patellofemoral ligament reconstruction reduces the number of drill sites in the patella.

Are luggage scales a viable alternative to hand-held dynamometers for the measurement of shoulder scaption strength?

Background

The accurate and reliable measurement of muscle strength is a valuable tool in most medical practices. The use of dynamometers allows for objective muscle strength assessment. Even so, dynamometry has its limitations due to increased cost and inconvenience in the clinic. Isokinetic dynamometers, the gold standard, are typically very large and expensive. However, smaller hand-held dynamometers are a cheaper and more efficient alternative. Hand-held dynamometers have been shown to demonstrate comparable reliability to the more expensive isokinetic dynamometers, despite their reduced cost and ease of use. Even though hand-held dynamometers are cheaper and more convenient to use in the clinical setting, their price tag is still burdensome for most medical practices, commonly costing $1000 or more. The aim of this study is to assess the reliability of luggage scales vs. dynamometers for measuring shoulder scaption strength.

Methods

One hand-held dynamometer was compared to two luggage scales using a set-up intended to mimic clinical testing. The set-up consisted of each device being tethered to the floor with the opposite end tied to a length of paracord that had been placed through a shoulder-height pulley and fastened to a flat plate used to hold the weight. In total, ten trials were completed, where a 2.3 kg (5 lb), 4.5 kg (10 lb), and 11.3 kg (25 lb). weight was measured by each device. Analysis of variance was used to compare the numerical data for the three groups.

Results

Our results indicate that there were no significant differences in the force measurements between each device (P = .99). The average force measurements between the three dynamometers were: 2.3 kg trial: 2.3 kg, 2.4 kg, and 2.2 kg; 4.5 kg trial: 4.5 kg, 4.6 kg, and 4.5 kg ; and 11.3 kg trial: 11.4 kg, 11.3 kg, and 11.4 kg. for the digital dynamometer, digital luggage scale, and the analog luggage scale, respectively. Subgroup analysis showed there was also no difference in force measurements between the 3 devices for the 2.3 kg, 4.5 kg, and 11.3 kg. trials (P = .14, P = .49, and P = .40, respectively).

Conclusion

Our data demonstrates that two inexpensive luggage scales showed no statistically significant differences in measurements compared to an expensive hand-held dynamometer. Utilization of luggage scales to measure shoulder scaption strength should yield similar results to handheld dynamometers. This may be an alternative, objective measure of manual muscle strength that is both efficient and economical.

Arthroscopic Simulation-Based Training of Orthopaedic Surgery Residents: Past, Present, and Future

Simulation-based training is required by many medical specialties. Barriers, however, have prevented widespread implementation of simulators for arthroscopic training. The advantages of arthroscopic simulator-based training of residents include decreased errors, decreased cost of training, and improved patient care. Before an educational program can focus on the type of simulator, it is essential to have a validated curriculum and framework for how to use those simulators. One of the most validated systems is called proficiency-based progression training. Proficiency-based progression is essentially a paradigm in which basic skills must be mastered and demonstrated via objective evaluation, before moving on to more advanced skills. There are a variety of different validation methods and tools that have been described, with the Arthroscopic Surgical Skill Evaluation Tool being the most widely used tool. It is essential that any simulator has evidence and validation that it will ultimately improve surgical skills in the operating room. In the future, emerging technologies such as virtual reality, augmented reality, and three-dimensional printing will likely play a major role in the creation of newer simulators and may improve access to residents throughout the world.

Comparison of ChatGPT-3.5, ChatGPT-4, and Orthopaedic Resident Performance on Orthopaedic Assessment Examinations

INTRODUCTION

Artificial intelligence (AI) programs have the ability to answer complex queries including medical profession examination questions. The purpose of this study was to compare the performance of orthopaedic residents (ortho residents) against Chat Generative Pretrained Transformer (ChatGPT)-3.5 and GPT-4 on orthopaedic assessment examinations. A secondary objective was to perform a subgroup analysis comparing the performance of each group on questions that included image interpretation versus text-only questions.

METHODS

The ResStudy orthopaedic examination question bank was used as the primary source of questions. One hundred eighty questions and answer choices from nine different orthopaedic subspecialties were directly input into ChatGPT-3.5 and then GPT-4. ChatGPT did not have consistently available image interpretation, so no images were directly provided to either AI format. Answers were recorded as correct versus incorrect by the chatbot, and resident performance was recorded based on user data provided by ResStudy.

RESULTS

Overall, ChatGPT-3.5, GPT-4, and ortho residents scored 29.4%, 47.2%, and 74.2%, respectively. There was a difference among the three groups in testing success, with ortho residents scoring higher than ChatGPT-3.5 and GPT-4 ( P < 0.001 and P < 0.001). GPT-4 scored higher than ChatGPT-3.5 ( P = 0.002). A subgroup analysis was performed by dividing questions into question stems without images and question stems with images. ChatGPT-3.5 was more correct (37.8% vs. 22.4%, respectively, OR = 2.1, P = 0.033) and ChatGPT-4 was also more correct (61.0% vs. 35.7%, OR = 2.8, P < 0.001), when comparing text-only questions versus questions with images. Residents were 72.6% versus 75.5% correct with text-only questions versus questions with images, with no significant difference ( P = 0.302).

CONCLUSION

Orthopaedic residents were able to answer more questions accurately than ChatGPT-3.5 and GPT-4 on orthopaedic assessment examinations. GPT-4 is superior to ChatGPT-3.5 for answering orthopaedic resident assessment examination questions. Both ChatGPT-3.5 and GPT-4 performed better on text-only questions than questions with images. It is unlikely that GPT-4 or ChatGPT-3.5 would pass the American Board of Orthopaedic Surgery written examination.

Improved Outcomes After Reinforced Radial Meniscus Repair Augmented With Bone Marrow Aspirate Concentrate

Purpose

To assess clinical outcomes of patients who have undergone surgical repair of radial meniscal tears with reinforced suture bar (rebar) technique augmented with bone marrow aspirate concentrate.

Methods

This is a retrospective study of a single fellowship-trained sports medicine surgeon's experience on all patients who underwent a reinforced repair (rebar) of a radial meniscus tear from November 2016 to 2018, with a minimum of 12-month follow-up. Lysholm scores, IKDC (International Knee Documentation Committee) Subjective Knee Form scores, and Tegner scale were collected postoperatively at periods for at least 1 year and retrospectively studied.

Results

Patients were followed for an average of 36.3 ± 25.0 months [range: 12.0-69.0 months]. Pain scores improved from 6.1 ± 2.1 to 0.4 ± 1.4 at 1 year (P < .001). IKDC Subjective Knee Form scores improved from 63 ± 26 to 90 ± 13 (P = .021). Lysholm scores improved from 64 ± 28 to 94 ± 9 (P = .025). Based on a calculated minimal clinical important difference (MCID) of 1.5, 100% of patients had improvement above the MCID. In addition, 88% of patients had a 1-year IKDC Subjective Knee Form score above the patient acceptable symptomatic state. Preoperative Tegner activity scale improved from 3 ± 1.5 to 8 ± 2.6 (P = .007). Patients returned to their preinjury activity with little difference in the Tegner activity scale when we compared preinjury and 1-year postoperative (8.1 ± 1.3 vs 8.0 ± 2.6 respectively, P = .317).

Conclusions

The rebar repair technique for radial meniscus tears, with bone marrow aspirate concentrate augmentation, showed improved outcomes in both pain and function at minimum follow-up of 12 months. Patients were able to return to a high preinjury activity level by 1 year, and 100% of patients had improvement above the MCID and 88% met patient acceptable symptomatic state.

Level of Evidence

Level IV, therapeutic case series.

Hormone Replacement Therapy Does Not Eliminate Risk Factors for Joint Complications following Total Joint Arthroplasty: A Matched Cohort Study

Aging causes a reduction in testosterone and estrogen, which is linked to diminished bone mineral density. Hormone replacement therapy and its effect on the outcome of joint arthroplasties is unclear. The purpose of this study was to analyze the impact of testosterone replacement therapy (TRT) and estrogen replacement therapy (ERT) on the medical and joint outcomes of total hip (THA) and total knee arthroplasties (TKA). A retrospective cohort study was conducted using the PearlDiver database. Patients who received TRT or ERT perioperatively were matched to controls. Rates of 90-day medical complications and 2-year joint complications were queried. Patients who received TRT had an increased risk of revision, periprosthetic joint infection, and pooled joint complications within 2 years following a THA and increased rates of septic and aseptic revisions, and aseptic loosening after TKA compared to the control cohort. Patients receiving ERT had increased rates of aseptic loosening and pooled joint complications within 2 years following THA and increased rates of all-cause revisions and pooled joint complications after TKA. Patients who received TRT demonstrated significantly higher rates of revision rates and PJI. Patients who received perioperative ERT were significantly more likely to have increased risks of revision rates and joint infections.

Compressibility of Osteochondral Autograft Transfer Donor Grafts: A Comparison of Different Donor Regions and How Much Shortening Occurs of Plugs After Impaction

Background

Osteochondral autograft transfer (OAT) is a useful technique for full-thickness cartilage lesions of the distal femur. Various techniques recommend harvesting a plug 2 mm longer than the recipient hole to allow for graft impaction. Grafts with limited compressibility may not sit flush when impacted.

Purpose

To compare the compressibility/shortening of OAT donor plug regions from the distal femur of human cadaveric knees after impaction.

Study Design

Controlled laboratory study.

Methods

A total of 20 cadaveric knees (mean age, 70.3 ± 8.4 years) were divided into 4 donor regions: medial intercondylar (IC) notch, lateral IC notch, medial trochlea, and lateral trochlea. Each region was subdivided into 4 zones: far superior (FSZ), middle superior (MSZ), middle inferior (MIZ), and far inferior (FIZ). A total of 320 grafts (6-mm diameter, 15-mm depth) were extracted, and a custom-built machine was used to strike the graft 5 times using a predetermined energy of 0.11 J. The graft length was measured initially and after each impact. Statistical analysis of the compressibility for each of the 4 regions and all 16 zones was performed utilizing analysis of variance, with post hoc testing using the Fisher's least significant difference.

Results

Compression in the lateral IC notch, medial IC notch, medial trochlea, and lateral trochlea was 2.4 ± 1.5, 2.1 ± 0.7, 3.1 ± 2.2, and 2.1 ± 0.6 mm, respectively, with significant differences between the 4 regions (P < .01) and the most compression in the medial trochlea (P < .01). Subgroup analysis showed that the lateral trochlea had higher compressibility for FIZ versus MIZ (P = .02) and the lateral IC notch had higher compressibility for FSZ versus FIZ and MIZ (P < .05 for both).

Conclusion

Compressibility varied between OAT donor sites in the distal femur. OAT donor grafts showed the highest compressibility in the medial trochlea (3.1 mm) and lateral IC notch FSZ (3.0 mm).

Clinical Relevance

The lateral trochlea, medial IC notch, and the lower zones of the lateral IC notch grafts should not be oversized more than 2 mm in length, as these grafts may not compress adequately.

COVID-19 Physician Burnout: Louisiana's Workforce Vulnerability and Strategies for Mitigation

Background: Louisiana is historically one of the lowest-performing states in terms of health outcomes in the United States. Hurricane Katrina led to a decrease in available health care resources, with a larger impact on resources for those living below the poverty line. Subsequently, the coronavirus disease 2019 (COVID-19) pandemic has been shown to have had disproportionately large impacts on minority communities, uninsured populations, and rural communities-all of which are found in Louisiana. Methods: This review focuses on the unique challenges of health care in Louisiana, the influence of COVID-19 on physician burnout, and methods of reducing work exhaustion for those in the health care field. Results: A national survey showed that physician satisfaction decreased from June 29, 2021, through September 26, 2021, compared to before the pandemic. A critical component in the provision of the essential services of public health is the ability to build and sustain a clinically skilled and diverse physician workforce. Maintaining well-being and retaining the physician workforce are prerequisites to the equitable provision of access to health care services. Conclusion: Maintaining one's own wellness is critical to occupational sustainability, particularly when unique stressors such as those encountered during the COVID-19 pandemic are present. The future of a vital health care system depends on physicians maintaining healthy habits and seeking help when burnout symptoms are recognized, both at the individual and institutional level.

Earlier Return to Light Duty Is Associated With Successful Return to Full Duty of Workers’ Compensation Patients Treated With Shoulder Arthroscopic Surgery

Purpose

To evaluate Workers’ Compensation (WC) patients who underwent arthroscopic shoulder surgery for workplace shoulder injuries and to determine whether there was an association between earlier return to light duty and earlier return to full duty.

Methods

After receiving institutional review board approval, we performed a retrospective chart review of all WC patients treated with shoulder arthroscopic surgery by 2 senior authors between 2011 and 2018. The patients were divided into 2 groups: Group 1 went back to light-duty work within the first 100 days after surgery, whereas group 2 performed light-duty work after 100 days or performed no light-duty work. The primary outcomes included the length of time from surgery to light-duty work and the length of time from surgery to return to the full-duty work level.

Results

A total of 59 patients met the inclusion criteria. There was a moderate correlation between the number of days at which the patients were released to light duty and the days they were able to be released to full duty (r = 0.35). In group 1 (light duty ≤ 100 days), 18 patients (75%) went back to full duty, whereas only 16 patients (46%) in group 2 were able to return to full-duty work (P = .025).

Conclusions

Earlier return to light duty is associated with earlier return to full duty after shoulder arthroscopic surgery in patients with a Workers’ Compensation claim. Additionally, WC patients who returned to early light duty in the first 100 days postoperatively had a higher rate of return to full duty than did patients who did not return to early light duty.

Level of Evidence

Level III, case-control study.

Medial Transmalleolar Portal Technique for Ankle Arthroscopic Headless Screw Fixation of Talar Osteochondritis Dissecans Lesions

This article describes a technique for arthroscopic fixation of an osteochondritis dissecans (OCD) lesion of the medial talar dome with headless compression screws. This technique involves creation of a medial transmalleolar portal using a guide and drill. The medial transmalleolar portal grants perpendicular access for screw fixation of OCD lesions in addition to the potential for osteochondral autograft transplantation (OAT). Advantages include access to the medial talar dome without performing a medial malleolar osteotomy. After completion of OCD fixation, an inverted osteochondral plug can be used to backfill the portal.

Improved Radiation Exposure Monitoring of Orthopaedic Residents After Institution of a Personalized Lead Protocol

Background:

Radiation exposure of orthopaedic residents should be accurately monitored to monitor and mitigate risk. The purpose of this study was to determine whether a personalized lead protocol (PLP) with a radiation monitoring officer would improve radiation exposure monitoring of orthopaedic surgery residents.

Materials and Methods:

This was a retrospective case-control study of 15 orthopaedic surgery residents monitored for radiation exposure during a 2-year period (March 2017 until February 2019). During the first 12-month period (phase 1), residents were given monthly radiation dosimeter badges and instructed to attach them daily to the communal lead aprons hanging outside the operating rooms. During the second 12-month period (phase 2), a PLP (PLP group) was instituted in which residents were given lead aprons embroidered with their individual names. A radiation safety officer was appointed who placed the badges monthly on all lead aprons and collected them at the end of the month, whereas faculty ensured residents wore their personalized lead apron. Data collected included fluoroscopy use time and radiation dosimeter readings during all orthopaedic surgeries in the study period.

Results:

There were 1,252 orthopaedic surgeries using fluoroscopy during phase 1 in the control group and 1,269 during phase 2 in the PLP group. The total monthly fluoroscopy exposure time for all cases averaged 190 minutes during phase 1 and 169 minutes during phase 2, with no significant difference between the groups (p < 0.45). During phase 1, 73.1% of the dosimeters reported radiation exposure, whereas during phase 2, 88.7% of the dosimeters reported radiation exposure (p < 0.001). During phase 1, the average monthly resident dosimeter exposure reading was 7.26 millirems (mrem) ± 37.07, vs. 19.00 mrem ± 51.16 during phase 2, which was significantly higher (p < 0.036).

Conclusions:

Institution of a PLP increased the compliance and exposure readings of radiation dosimeter badges for orthopaedic surgery residents, whereas the actual monthly fluoroscopy time did not change. Teaching hospitals should consider implementing a PLP to more accurately monitor exposure.

Level of Evidence:

3.

Ideal Donor Site for Osteochondral Autografting of the Distal Femur Using Radius of Curvature: A 3-Dimensional High-Resolution Scanner Comparison

OBJECTIVE

To compare radius of curvature (RoC) of distal femur osteochondral autograft transfer (OAT) donor sites from the intercondylar notch and trochlear ridge with recipient sites on the distal and posterior condyles and evaluate differences between recipient sites.

DESIGN

Nineteen cadaveric femurs were scanned with a 3-dimensional high-resolution sensor. Donor regions included the lateral (LTR) and medial trochlear ridges (MTR), and the lateral (LICN) and medial intercondylar notch (MICN). Recipient regions analyzed were the distal medial (DMFC), posterior medial (PMFC), distal lateral (DLFC), and posterior lateral femur condyle (PLFC). Six-millimeter OAT grafts were simulated, and average RoC of all regions was compared using an analysis of variance. Post hoc testing was performed using Fisher's least significant difference.

RESULTS

We found no significant differences in RoC of the LICN compared with all 4 recipient sites (P = 0.19, 0.97, 0.11, and 0.75 for DLFC, PLFC, DMFC, and PMFC, respectively) or the LTR and MTR to the posterior condyles (LTR vs. PLFC and PMFC; P = 0.72, 0.47, MTR vs. PLFC and PMFC P = 0.39, 0.22, respectively). Significant differences were found for RoC of the MICN compared with each recipient site (P < 0.001) and between distal and posterior femoral condyles (DLFC vs. PLFC, P = 0.016; DMFC vs. PMFC, P = 0.023).

CONCLUSION

The LICN is the ideal donor option for all recipient sites on the femoral condyles with respect to RoC of 6-mm OAT plugs. The MTR and LTR were acceptable donor sources for the posterior condyles, while the MICN was a poor match for all recipient sites. Additionally, the distal femur condyle and posterior femur condyle have different RoCs.

The Ideal Cortical Button Location on the Lateral Femur for Anterior Cruciate Ligament Suspensory Fixation is 30 mm Proximal to the Lateral Epicondyle

Purpose

To determine the ideal location for anterior cruciate ligament (ACL) suspensory cortical button placement on the lateral femur with the highest failure load and to establish the relationship of tunnel diameter and cortical thickness on load to failure.

Methods

Computed tomography (CT) data were obtained from 45 cadaveric distal femurs. A Cartesian coordinate system was established along the lateral femur with the lateral epicondyle (LE) as a reference point. Locations 0, 20 and 30 mm from the LE along lines 0°, 25°, 50°, and 75° posterioproximal from the axial plane were created. Tunnels connecting from each location to the center of the ACL footprint were simulated. Cortical thickness and long axis diameter of the oval cortical holes were determined for each location. Based on the CT data, custom drill guides were created and used to drill 4.5 mm tunnels at each lateral femur location to the ACL footprint on the cadaver femurs. Cortical buttons were placed at each location and pulled using a servohydraulic testing system. The correlation of tunnel diameter and cortical thickness to button failure load were analyzed using a regression analysis.

Results

Significant differences were found for failure load (P<.0001) and cortical thickness between the locations tested (P<.0001). The location 30 mm proximal from the LE and 75⁰ from the axial plane had the highest failure load of 573 N. A regression analysis (R² = .15) indicated that the cortical thickness was significantly correlated with load to failure (P <.0001), whereas the long-axis diameter was not (P = .33).

Conclusion

The ideal cortical button location on the lateral femur for ACL suspensory fixation was located 30 mm proximal from the lateral epicondyle, based on this area’s high failure load. Oblique tunnel drilling of this proximal location may cause a larger long-axis diameter cortical hole, but the cortex is also thicker, which is more closely correlated with failure load.

Clinical Relevance

Different ACL suspensory cortical button locations on the lateral femur have different failure loads based on the cortical thickness of the bone supporting the button. It is important for surgeons to understand which drilling techniques place the button in a proximal and posterior location, especially if the bone quality of the patient is of concern.

Arthroscopic Fixation of Knee Femoral Condyle Osteochondritis Dissecans Fragment With Bone Marrow Aspirate Concentrate

This article reviews a technique for arthroscopic fixation of an osteochondritis dissecans fragment with bone marrow aspirate concentrate augmentation. This technique involves safe harvest of bone marrow arthroscopically from the intercondylar notch, proper preparation and debridement of the parent bone, reduction of the progeny osteochondritis dissecans fragment, insertion of the bone marrow aspirate concentrate, and placement of multiple headless compression screws for fixation.

Nitinol Memory Rods Versus Titanium Rods: A Biomechanical Comparison of Posterior Spinal Instrumentation in a Synthetic Corpectomy Model

STUDY DESIGN

Biomechanical investigation.

OBJECTIVE

To compare the biomechanical performance of nitinol memory metal rods and titanium rods when used as posterior spinal instrumentation in a synthetic model.

METHODS

Biomechanical testing was performed using ultra-high-molecular-weight polyethylene blocks. Nineteen spinal constructs were created to allow comparison of 5.5-mm nitinol rods with 5.5-mm titanium rods. Static compression and rotational testing were performed on an Instron 8874 and Instron 4202 at 37°C to simulate body temperature.

RESULTS

The average titanium construct stiffness under static compression or bending was 47.2 ± 9.1 N/mm while nitinol's stiffness averaged 48.9 ± 12.4 N/mm (P = .83). During axial rotation testing, the nitinol rod system showed no torsional stiffness difference from the titanium system: 0.95 ± 0.03 Nm/deg versus 0.96 ± 0.17 Nm/deg, respectively (P = 0.91). There was a statistically significant difference between the average torsional yield point for the titanium constructs (14.4 ± 1.6 Nm/deg) and nitinol constructs (21.3 ± 0.8 Nm/deg) (P = .004). The torsional toughness of the nitinol constructs was also statistically greater than the titanium rods: 473 GN/m³ versus 784 GN/m³ (P = .0006). There was no statistically significant difference between the nitinol group sustaining a higher number of fatigue cycles until failure and the titanium group (181 660 cycles vs 64 104 cycles, respectively, P = .22).

CONCLUSIONS

This study provides biomechanical evidence that nitinol rods used in a posterior construct are comparable to titanium rods with regard to compression and have increased torsional failure load and torsional toughness. While nitinol trended toward superior fatigue resistance, there was no significant difference in nitinol versus titanium construct fatigue resistance.

Biomechanical Analysis of Patellar Tendon Repair With Knotless Suture Anchor Tape Versus Transosseous Suture

Background

Patellar tendon ruptures have routinely been repaired with transosseous suture tunnels. The use of knotless suture anchors for repair has been suggested as an alternative.

Purpose

To compare the load to failure and gap formation of patellar tendon repair at the inferior pole of the patella with knotless suture anchor tape versus transosseous sutures. A secondary objective was to investigate whether either technique shows an association between bone density and load to failure.

Study Design

Controlled laboratory study.

Methods

A total of 20 human tibias with attached patellar and quadriceps tendons were sharply incised at the bone-tendon junction at the inferior pole of the patella. A total of 10 tendons were repaired using 2 knotless suture anchors in the inferior pole of the patella and a single suture tape with 2 core sutures. The other 10 tendons were repaired using No. 2 suture passed through 3 transosseous tunnels. A distracting force was then applied through the suture in the quadriceps tendon. Gap distance through load cycling at the repair site and maximum load at repair failure were then measured. Bone density was measured using computed tomography scanning.

Results

No difference was found in the mean load to failure of knotless patellar tendon repair versus transosseous suture repair (367.6 ± 112.2 vs 433.9 ± 99 N, respectively; P = .12). After 250 cycles, the mean repair site gap distance was 0.85 ± 0.45 mm for the knotless patellar tendon repair versus 2.94 ± 2.03 mm for the transosseous suture repair (P = .03). A small correlation, although not statistically significant, was found between bone density and load to failure for the knotless tape repair (R ² = 0.228; P = .66). No correlation was found between bone density and load to failure for the transosseous repair (R ² = 0.086; P = .83).

Conclusion

Suture tape repair with knotless anchors for repair of patellar tendon rupture has comparable load to failure with less gap formation than transosseous suture repair. There is a small correlation between bone density and failure load for knotless anchor repair, which may benefit from further investigation.

Clinical Relevance

Using knotless suture anchors for patellar tendon rupture repair would allow for a smaller incision, less dissection, and likely shorter operating time.

Bucket-Handle Meniscus Repair in a Below-Knee Amputee: A Case Report

CASE

We report a case of a right knee lateral bucket-handle meniscal tear repair in a 25-year-old woman bilateral below-knee amputee. At the 4-year follow-up, the patient was ambulatory in a prosthesis with a successful outcome.

CONCLUSION

Meniscus repair in below-knee amputees requires careful evaluation and surgical management. Specific consideration should be given to evaluating limb alignment, maintaining the stump integrity, surgical technique, modified bracing, and rehabilitation. This case report demonstrates that bucket-handle meniscus repair can be successful in a below-knee amputee.

Synovial fluid leukocyte cell count before versus after administration of antibiotics in patients with septic arthritis of a native joint

BACKGROUND

Antibiotics have been shown to affect the accuracy of cultures; so antibiotics are held prior to obtaining cultures intra-operatively. No study has evaluated the effects of antibiotics on synovial fluid leukocyte cell count. The purpose of the current study is to compare the leukocyte cell count of native joints with septic arthritis when antibiotics have been given before aspiration and when no antibiotics have been given prior to aspiration.

METHODS

This study was performed at a community hospital and a level 1 urban trauma hospital after IRB approval from both institutions from July 2007 to July 2017. Inclusion criteria comprised of a diagnosis of septic arthritis with positive cultures and a recorded arthrocentesis with cell count performed. Patients with septic arthritis were identified using ICD-9 codes 711.00-711.99 and ICD-10 codes M00 - M02. A retrospective chart review was performed and data was collected. Patients were placed into one of two groups. Group 1 received no antibiotics for two weeks prior to arthrocentesis, group 2 received antibiotics within 24 h prior to arthrocentesis. Demographic information, cell count number and differential, and blood lab values were collected. Timing data was also collected on timing of admission, antibiotics, joint irrigation, and discharge from the inpatient setting.

RESULTS

There were 81 patients meeting final inclusion criteria. The average cell count for the group which received antibiotics (n = 30) was 40,408 ± 29,433 while the average cell count for the group receiving no antibiotics (n = 51) was 93,824 ± 73,875 (p < .0001). The average length of stay was not significantly different between the antibiotic group versus no antibiotic group (14.0 days vs 12.1 days p = .4). The time from admission to arthrocentesis and admission to washout was longer for the antibiotic group versus no antibiotic group (p = .004 and p = .002, respectively).

CONCLUSION

When antibiotics are given prior to arthrocentesis of a septic joint, there is an associated lower synovial fluid leukocyte count compared to when no antibiotics are given prior.

LEVEL OF EVIDENCE

Level III.

Adapting Orthopaedic Surgery Training Programs During the COVID-19 Pandemic and Future Directions

The COVID-19 pandemic swept across the world, altering the structure and existence of graduate medical education programs across all disciplines. Orthopaedic residency programs can adapt during these unprecedented times to continue providing meaningful education to trainees and to continue providing high-quality patient care, all while keeping both residents and patients safe from disease. The purpose of this review was to evaluate the literature and describe evidence-based changes that can be made in an orthopaedic residency program to ensure patient and resident safety while sustaining the principles of graduate medical education during the COVID-19 pandemic. We describe measures that can be enacted now or during future pandemics, including workforce and occupational modifications, personal protective equipment, telemedicine, online didactic education, resident wellness, return to elective surgery, and factors affecting medical students and fellows. After a review of these strategies, programs can make changes for sustainable improvements and adapt to be ready for second-wave events or future pandemics.

Level of Evidence

Level V.

Notch Signaling in Osteogenesis, Osteoclastogenesis, and Angiogenesis

Skeletal tissue development and regeneration in mammals are intricate, multistep, and highly regulated processes. Various signaling pathways have been implicated in the regulation of these processes, including Notch. Notch signaling is a highly conserved, intercellular signaling pathway that regulates cell proliferation and differentiation, determines cell fate decision, and participates in cellular process in embryonic and adult tissue. Here, we review recent data showing the regulation of Notch signaling in osteogenesis, osteoclastogenesis, and angiogenesis. These processes are cell-context-dependent via direct or indirect mechanisms. Furthermore, Notch signaling may be highly beneficial for efficient coupling of osteogenesis and angiogenesis for tissue engineering and skeletal repair, which is critical to develop clinically therapeutic options.

Critical Analysis of the Lever Test for Diagnosis of Anterior Cruciate Ligament Insufficiency

PURPOSE

To critically analyze the "lever test" in detecting anterior cruciate ligament (ACL) tears and to compare its accuracy with the Lachman, anterior drawer (AD), and pivot shift tests.

METHODS

From June 2014 to June 2015, 91 subjects were analyzed. Inclusion criteria were subjects aged 16 to 60 years, presenting after a knee injury with subjective swelling, or an objective effusion and an uninjured normal contralateral knee for comparison. Exclusion criteria included previous knee ligamentous reconstruction, fracture of the distal femur or proximal tibia, bilateral knee injuries, or known cruciate ligament tear. The Lachman, AD, pivot shift, and lever tests were performed in the office by 2 board-certified orthopaedic surgeons with patient awake. Examiners were blinded to the presence or absence of ACL injury. Magnetic resonance imaging was used to determine injury. Sensitivity, specificity, and accuracy were evaluated for all 4 tests. Accuracy was compared using χ-square and receiver operator curves.

RESULTS

Average subject age was 28 ± 11 years (61 males, 30 females). Seventy-one (79%) had ACL tears diagnosed by magnetic resonance imaging. The sensitivity, specificity, and accuracy of the lever test were 83%, 80%, and 82%, respectively. Accuracy was not statistically different from the Lachman, AD, and pivot shift tests (P = .78, .99, .07, respectively). Subanalyses were performed based on the presence of another ligament tear, timing of injury, and the presence of a meniscus tear. Although the groups were smaller and thus underpowered, the results were reported. Neither the presence of another ligament tear nor the timing of the injury affected accuracy (P = .62 and P = .47); however, the presence of a meniscus tear decreased its accuracy (P = .003).

CONCLUSIONS

The lever test showed high sensitivity, specificity, and overall accuracy in the detection of ACL tears. The accuracy of the lever test was not significantly different from the Lachman, AD, or pivot shift tests.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Prevalence of Low Bone Mineral Density in Younger Versus Older Women With Distal Radius Fractures

Although distal radius fractures (DRFs) are the most common fractures among younger women, few studies have examined bone health in this age group. We compared bone mineral density (BMD) of younger women (35-50 years) and older women (>50 years) treated for DRFs. Between January 2005 and August 2010, our orthopedic service obtained dual-energy x-ray absorptiometry scans from 128 women with DRFs (47 were 35-50 years old; 81 were older than 50 years). According to the World Health Organization classification system, 43% of the younger patients were osteopenic, and 6% were osteoporotic. Mean femoral neck BMD was 0.91 for the younger group and 0.80 for the older group (P < .05); t scores were -0.87 and -1.65, respectively (P < .05). The difference in femoral neck z scores between the younger and older patients was not statistically different: -0.69 and -0.67, respectively (P = .92). A notable proportion of younger patients with DRFs have osteopenia or osteoporosis. The similarity in z scores among younger and older women with DRFs and among patient groups differentiated by mechanism of injury suggests that any younger or older woman with a DRF should have her BMD evaluated and treated as appropriate.