Threshold-Responsive Colorimetric Sensing System for the Continuous Monitoring of Gases.

Colorimetric sensors are widely used because of their inherent advantages including accuracy, rapid response, ease-of-use, and low costs; however, they usually lack reusability, which precludes the continuous use of a single sensor. We have developed a threshold-responsive colorimetric system that enables repeated analyte measurements by a single colorimetric sensor. The threshold responsive algorithm automatically adjusts the sensor exposure time to the analyte and measurement frequency according to the sensor response. The system registers the colorimetric sensor signal change rate, prevents the colorimetric sensor from reaching saturation, and allows the sensor to fully regenerate before the next measurement is started. The system also addresses issues common to colorimetric sensors, including the response time and range of detection. We demonstrate the benefits and feasibility of this novel system, using colorimetric sensors for ammonia and carbon dioxide gases for continuous monitoring of up to (at least) 60 detection cycles without signs of analytical performance degradation of the sensors.

Sacroiliac joint fusion navigation: how accurate is pin placement?

OBJECTIVE: Sacroiliac joint (SIJ) fusion utilizing intraoperative navigation requires a standard reference frame, which is often placed using a percutaneous pin. Proper placement ensures the correct positioning of SIJ fusion implants. There is currently no grading scheme for evaluation of pin placement into the pelvis. The purpose of this study was to evaluate the occurrence of ideal percutaneous pin placement into the posterior ilium during navigated SIJ fusion. METHODS: After IRB approval was obtained, electronic medical records and intraoperative computed tomography images of patients who underwent navigated SIJ fusion by the senior author between October 2013 and January 2020 were reviewed. A pin placement grading scheme and the definition of "ideal" placement were developed by the authors and deemed acceptable by fellow attending surgeons. Six attending surgeons completed two rounds of pin placement grading, and statistical analysis was conducted. RESULTS: Of 90 eligible patients, 73.3% had ideal pin placement, 17.8% medial/lateral breach, and 8.9% complete miss. Male patients were 3.7 times more likely to have ideal placement than females (p < 0.05). There was no relationship between BMI, SIJ fusion laterality, or pin placement laterality and ideal placement. Interobserver reliability was 0.72 and 0.70 in the first and second rounds, respectively, and defined as "substantial agreement." Intraobserver reliability ranged from 0.74 (substantial agreement) to 0.92 (almost perfect agreement). CONCLUSIONS: Nonideal pin placement occurred in 26.7% of cases, but a true "miss" into the sacrum was rare. Ideal pin placement was more likely in males and was not associated with BMI, SIJ fusion laterality, or pin placement laterality. The grading scheme developed has high intraobserver and interobserver reliability, indicating that it is reproducible and can be used for future studies. When placing percutaneous pins, surgeons must be aware of factors that can decrease placement accuracy, regardless of location.

Arthroscopic Lysis of Adhesions for the Stiff Total Knee Arthroplasty.

Background: Arthroscopic lysis of adhesions is a treatment option for patients with painful, stiff knees as a result of arthrofibrosis following knee arthroplasty, in whom prior manipulation under anesthesia (MUA) has failed. Typically, nonoperative treatment in these patients has also failed, including aggressive physiotherapy, stretching, dynamic splinting, and various pain-management measures or medications. Range of motion in these patients is often suboptimal, and any gains in flexibility will likely have hit a plateau over many months. The goal of performing lysis of adhesions is to increase the range of motion in patients with knee stiffness following total knee arthroplasty, as well as to reduce pain and restore physiologic function of the knee, enabling activities of daily living. Description: This is a straightforward surgical technique that can be performed in a single stage. The preoperative range of motion is documented after induction of general anesthesia. The procedure begins with the establishment of standard medial and lateral parapatellar arthroscopic portals. A blunt trocar is introduced into the knee, and blunt, manual lysis of adhesions is performed in the suprapatellar pouch and the medial and lateral gutters with use of a sweeping motion after piercing and perforating the scarred adhesive bands or capsular tissue. Next, the arthroscope is inserted into the knee, and a diagnostic arthroscopy is performed. Bands of fibrous tissue are released and resected with use of electrocautery and a 4.0-mm arthroscopic shaver. Next, the posterior cruciate ligament (PCL) is visualized in full flexion. If PCL tightness is observed, the PCL can be released from its femoral origin until the flexion gap is increased. This portion of the procedure can include either partial or full release of the PCL, as indicated. Next, the arthroscope is removed and the ipsilateral hip is flexed to 90° for a standard MUA. Gentle force is applied to the proximal aspect of the tibia, and the knee is flexed. After completing the MUA, immediate post-intervention range of motion of the knee is documented, and the patient is provided with a continuous passive motion (CPM) machine set to the maximum flexion and extension achieved in the operating room. Alternatives: Nonoperative treatment of a stiff knee following total knee arthroplasty is well documented in the current literature. Range of motion has been shown to increase in patients undergoing proper pain management, aggressive physical therapy, and closed MUA in the acute postoperative setting. Additionally, more severe cases of established arthrofibrosis despite prior MUA can be treated with an open lysis of adhesions1-3. Rationale: Arthroscopic lysis of adhesions with PCL release versus resection has been well described previously. This procedure has been shown to benefit patients in whom initial nonoperative treatment has failed. Additionally, this procedure is not limited to the immediate acute postoperative period like standard MUA3. To our knowledge, no technique video has been published outlining arthroscopic lysis of adhesions for a stiff knee following total knee arthroplasty. Expected Outcomes: This procedure has been shown to provide an immediate and lasting improvement in the flexion and extension arc of the knee, as well as improved functional outcomes. Patients should be educated that improvements gained in the operating room must be sustained through physical therapy. In a study of 32 patients who underwent arthroscopic lysis of adhesions for moderately severe arthrofibrosis following a total knee arthroplasty, Jerosch and Aldawoudy reported a mean postoperative flexion of 119° in the operating room and 97° at the time of the latest follow-up. Eight patients with extensor lag showed improvement from 27° to 4°. Average Knee Society scores improved from 70 points preoperatively to 86 points at the time of the latest follow-up4. Their article showed that arthroscopic treatment of stiffness following total knee arthroplasty is a safe and effective form of treatment. Important Tips: Perform manual lysis of adhesions with a trocar prior to inserting the arthroscope in order to improve visualization and access.Utilize all portals and accessory portals interchangeably in order to improve access.Prescribe physical therapy with or without CPM machine immediately following surgery in order to maintain correction.Utilize pump inflow in order to help distend the tightened capsule.Protect the prosthetic surface from scratches during portal establishment.Loss of flexion implies scarring in the suprapatellar pouch and/or intercondylar notch, or PCL tightness.Loss of extension implies a tight posterior capsule, posterior osteophytes, or scarring of the PCL stump.A motorized shaver is the best tool for treatment of dense fibrous tissue, but be sure not to scratch metal total knee components. Acronyms and Abbreviations: TKA = total knee arthroplastyROM = range of motionCT = computed tomographyMRI = magnetic resonance imagingESR = erythrocyte sedimentation rateCRP = C-reactive protein.

Prospective Trial of Neutrophil/Lymphocyte Ratio and Other Blood Counts as Biomarkers of Survival among Patients with High-Grade Soft Tissue Sarcomas Treated with Pegylated Liposomal Doxorubicin and Ifosfamide.

Several studies have reported an association between levels of circulating blood cells, in particular the neutrophil to lymphocyte ratio (absolute neutrophil count (ANC)/absolute lymphocyte count (ALC)) and outcomes in patients with cancer. In the current study, the association between lymphocyte, neutrophil, monocyte, and platelet counts and survival was examined in a prospective trial of preoperative pegylated-liposomal doxorubicin and ifosfamide for high-grade soft-tissue sarcomas. A statistically significant association between overall survival, but not progression free-survival, was observed with the ANC/ALC ratio at a cutoff value of ≥2 and a statistically significant trend using a cutoff of ≥5. Our results suggest that a balance between the lymphocyte count and the number of circulating myeloid cells that can suppress lymphocyte function may be predictive of survival in patients with soft-tissue sarcomas. Future research should therefore examine the role of lymphocyte-myeloid cell balance in sarcoma biology.

Optical coherence tomography for surgical margin evaluation of excised canine cutaneous and subcutaneous tumours.

Currently, intraoperative tumour margin imaging is not routinely utilized in veterinary medicine. Optical coherence tomography (OCT) allows for real-time assessment of tissue morphology of 1-2 mm depth. The aims of this study were (1) to compare the histologic and OCT features of excised canine skin and subcutaneous specimens, and (2) to determine the diagnostic accuracy of OCT for surgical margin evaluation. The authors hypothesized that OCT imaging would correlate well with histopathology and that OCT would be sensitive for detection of incomplete margins. Eighty dogs were prospectively enrolled. Tumours were excised, and the surgical margins were imaged using a spectral domain OCT system. The tumour type and completeness of excision were determined by histopathology. Nine blinded observers received training in OCT image interpretation and were then given a set of OCT images and videos. The observers assigned each image/video a grade from 1 (no tumour) to 4 (tumour) and the results were compared to histopathology. The overall median sensitivity and specificity of OCT imaging for detection of incomplete margins were 86.7% and 84.6%, respectively. A potential limitation is that observers had varied experience with OCT image interpretation, ranging from no prior experience to participating in a previous OCT project. OCT is sensitive for detection of incomplete margins and could be a promising real-time surgical margin imaging modality. Further study is needed to evaluate intraoperative applications of OCT and its impact on tumour recurrence and long-term outcome.

Prospective Trial of Monocyte Count as a Biomarker of Hand-Foot Syndrome Among Patients With Soft Tissue Sarcomas Treated With Pegylated Liposomal Doxorubicin and Ifosfamide.

Pegylated liposomal doxorubicin (PLD) is widely used and can be used for prolonged periods, with the limiting toxicity usually being hand-foot syndrome (HFS). The pharmacokinetics of PLD is variable between patients, leading to variability in the risk of developing HFS. Dosing based on body surface area does not decrease variability in PLD clearance; thus, other predictive markers could be useful. The peripheral blood absolute monocyte count (AMC) has been suggested as a possible marker of both reticuloendothelial system function and PLD pharmacokinetics. The present study examined the AMC as a potential predictive biomarker in a prospective trial of pre-operative PLD combined with ifosfamide in soft tissue sarcomas (STSs). While our results suggest a relationship between pre-treatment AMC and PLD-induced HFS, the association did not reach statistical significance. The clinical utility of the AMC as a predictor of PLD-induced HFS appears limited, at least when given with ifosfamide.

Sliding Hip Screw and Side Plate for Intertrochanteric Hip Fractures.

For stable intertrochanteric hip fractures, treatment commonly involves the use of a sliding hip screw. Intertrochanteric hip fractures are increasingly common as the population ages and lives longer. More than 250,000 hip fractures occur per year in the United States1. The mortality rate within the first year following operative treatment ranges from 14% to 27.3%2,3. Early surgical repair within 48 hours of injury is associated with a lower risk of mortality2,4,5. The goals of surgical treatment are restoration of coronal plane alignment without varus angulation and early patient mobilization. Description: The sliding hip screw procedure can be divided into (1) preoperative planning; (2) patient positioning; (3) C-arm setup; (4) closed reduction of fracture; (5) sterile preparation and draping; (6) lateral hip approach; (7) guide pin insertion; (8) triple-reaming the proximal aspect of the femur; (9) sliding hip screw insertion into the femoral neck and head; (10) side plate insertion, engaging the sliding hip screw, and fixation to the femur; (11) lag compression screw insertion (if appropriate); and (12) final fluoroscopic images and wound closure. Alternatives: Intertrochanteric hip fractures must be surgically treated to avoid morbidity and increased risk of mortality. Nonoperative treatment is occasionally indicated in nonambulatory patients or those with high perioperative risk. If treated surgically, a common alternative implant option includes the intramedullary nail. Finally, for severely comminuted fractures or failed internal fixation, total hip arthroplasty may be necessary. Rationale: Sliding hip screws are as effective as intramedullary nails and often less costly6. In general, the quality of fracture reduction is more critical than the choice of implant7. A prospective study found no significant difference in walking ability with either sliding hip screws or intramedullary nails for stable intertrochanteric fractures8. Expected Outcomes: By 6 months, the majority of fractures will have healed; according to a prospective randomized study, 91% of stable fractures and 85% of unstable fractures had achieved radiographic union by that time9. Another study showed radiographically healed fractures in all 106 patients treated with sliding hip screws at median follow-up of 13.6 months8. Important Tips: Watch out for comminution of the greater or lesser trochanter, which may require supplemental fixation.Prior to completely reflecting the vastus lateralis muscle, control the bleeding from any perforators with use of 2-0 silk ties. This prevents recurrent bleeding, which often occurs if only cautery is utilized to coagulate these vessels.Utilize a 4.5-mm drill hole in the lateral cortex of the femur in order to allow for minor adjustments of the anterior femoral neck guide pin; otherwise, the pin will be held tightly and continue to be bound in the same direction by the lateral cortex on repeated attempts.If the guide pin is inadvertently withdrawn along with the reamer after reaming, a lag screw may be placed backward in the newly reamed hole and the guide pin passed back through the lag screw to reposition it.Extracapsular hip fractures should be carefully scrutinized for signs of instability, such as lateral wall comminution or reverse obliquity. The fracture may displace posteriorly when the patient is supine on the fracture table.While placing the guidewire, multiple entry attempts can weaken the lateral cortex and propagate the fracture into the subtrochanteric region.Superior placement of the lag screw results in poor tip-apex distance and a higher chance of screw cut-out.Be careful to prevent guidewire penetration into the hip joint.Loss of reduction or femoral head malrotation may occur during lag screw insertion. Acronyms & Abbreviations: AP = anteroposteriorfx's = fracturesIMN = intramedullary nailIV = intravenousPDS = polydioxanone sutureSHS = sliding hip screwTFL = tensor fascia lata.

Core Decompression and Bone Marrow Aspiration Concentrate Grafting for Osteonecrosis of the Femoral Head.

BACKGROUND: Core decompression (CD) with bone marrow aspiration concentrate (BMAC) is a technique that may improve outcomes in osteonecrosis of the femoral head (ONFH). The primary aim of this study was to evaluate the radiographic progression free survival (PFS) of CD augmented with BMAC. Secondary aims were to determine the survivorship with conversion (CFS) to total hip arthroplasty (THA) as an endpoint, determine prognostic factors, and characterize the cellular quality of the BMAC. METHODS: A retrospective cohort study of 61 femoral heads (40 patients) was performed. Patient demographics, comorbidities, BMI, smoking status, etiology, location and extent of ONFH were recorded. The primary endpoint was radiographic progression of ONFH and secondarily, conversion to THA. Additional aims were to determine predictive factors for progression and report the cellular characteristics of the BMAC. Data obtained were compared to the results of a prior randomized controlled trial comparing CD alone versus CD with polymethylmethacrylate cement (PMMA) augmentation. RESULTS: Radiographic PFS of CD with BMAC at 2 and 5 years was 78.3% and 53.3%, respectively. The risk of progression was lower in the CD with BMAC group compared to CD alone (HR0.45, p = 0.03), however this difference no longer remained statistically significant on multivariate analysis. Conversion to total hip arthroplasty free survival (CFS) of CD with BMAC at both 2 and 5 years was 72.1% and 54.6%, respectively with no differences compared to the control groups (CD alone, CD and PMMA). The predictive factors for progression were obesity (BMI ≥ 30) and the extent of the disease as quantified by either percentage involvement, necrotic index or modified necrotic index. CONCLUSIONS: No differences in PFS or CFS between CD with BMAC compared to CD alone or CD with PMMA were identified. Independent statistically significant predictors of progression-free survival or conversion to THA are BMI ≥ 30 and the extent of ONFH. Further research with an adequately powered randomized controlled trial is needed. LEVEL OF EVIDENCE: 3.

The 2021 Association Research Circulation Osseous Classification for Early-Stage Osteonecrosis of the Femoral Head to Computed Tomography-Based Study.

BACKGROUND: The Association Research Circulation Osseous developed a novel classification for early-stage (precollapse) osteonecrosis of the femoral head (ONFH). We hypothesized that the novel classification is more reliable and valid when compared to previous 3 classifications: Steinberg, modified Kerboul, and Japanese Investigation Committee classifications. METHODS: In the novel classification, necrotic lesions were classified into 3 types: type 1 is a small lesion, where the lateral necrotic margin is medial to the femoral head apex; type 2 is a medium-sized lesion, with the lateral necrotic margin being between the femoral head apex and the lateral acetabular edge; and type 3 is a large lesion, which extends outside the lateral acetabular edge. In a derivation cohort of 40 early-stage osteonecrotic hips based on computed tomography imaging, reliabilities were evaluated using kappa coefficients, and validities to predict future femoral head collapse by chi-squared tests and receiver operating characteristic curve analyses. The predictability for future collapse was also evaluated in a validation cohort of 104 early-stage ONFH. RESULTS: In the derivation cohort, interobserver reliability (k = 0.545) and intraobserver agreement (63%-100%) of the novel method were higher than the other 3 classifications. The novel classification system was best able to predict future collapse (P < .05) and had the best discrimination between non-progressors and progressors in both the derivation cohort (area under the curve = 0.692 [0.522-0.863], P < .05) and the validation cohort (area under the curve = 0.742 [0.644-0.841], P = 2.46 × 10-5). CONCLUSION: This novel classification is a highly reliable and valid method of those examined. Association Research Circulation Osseous recommends using this method as a unified classification for early-stage ONFH. LEVEL OF EVIDENCE: Level III, diagnostic study.

Comparison of Prophylactic Intravenous Antibiotic Regimens After Endoprosthetic Reconstruction for Lower Extremity Bone Tumors: A Randomized Clinical Trial.

IMPORTANCE: The use of perioperative, prophylactic, intravenous antibiotics is standard practice to reduce the risk of surgical site infection after oncologic resection and complex endoprosthetic reconstruction for lower extremity bone tumors. However, evidence guiding the duration of prophylactic treatment remains limited. OBJECTIVE: To assess the effect of a 5-day regimen of postoperative, prophylactic, intravenous antibiotics compared with a 1-day regimen on the rate of surgical site infections within 1 year after surgery. DESIGN, SETTING, AND PARTICIPANTS: This randomized clinical superiority trial was performed at 48 clinical sites in 12 countries from January 1, 2013, to October 29, 2019. The trial included patients with a primary bone tumor or a soft tissue sarcoma that had invaded the femur or tibia or oligometastatic bone disease of the femur or tibia with expected survival of at least 1 year who required surgical management by excision and endoprosthetic reconstruction. A total of 611 patients were enrolled, and 7 were excluded for ineligibility. INTERVENTIONS: A 1- or 5-day regimen of postoperative prophylactic intravenous cephalosporin (cefazolin or cefuroxime) that began within 8 hours after skin closure and was administered every 8 hours thereafter. Those randomized to the 1-day regimen received identical saline doses every 8 hours for the remaining 4 days; patients, care providers, and outcomes assessors were blinded to treatment regimen. MAIN OUTCOMES AND MEASURES: The primary outcome in this superiority trial was a surgical site infection (superficial incisional, deep incisional, or organ space) classified according to the criteria established by the Centers for Disease Control and Prevention within 1 year after surgery. Secondary outcomes included antibiotic-related complications, unplanned additional operations, oncologic and functional outcomes, and mortality. RESULTS: Of the 604 patients included in the final analysis (mean [SD] age, 41.2 [21.9] years; 361 [59.8%] male; 114 [18.9%] Asian, 43 [7.1%] Black, 34 [5.6%] Hispanic, 15 [2.5%] Indigenous, 384 [63.8%] White, and 12 [2.0%] other), 293 were randomized to a 5-day regimen and 311 to a 1-day regimen. A surgical site infection occurred in 44 patients (15.0%) allocated to the 5-day regimen and in 52 patients (16.7%) allocated to the 1-day regimen (hazard ratio, 0.93; 95% CI, 0.62-1.40; P = .73). Antibiotic-related complications occurred in 15 patients (5.1%) in the 5-day regimen and in 5 patients (1.6%) allocated to the 1-day regimen (hazard ratio, 3.24; 95% CI, 1.17-8.98; P = .02). Other secondary outcomes did not differ significantly between treatment groups. CONCLUSIONS AND RELEVANCE: This randomized clinical trial did not confirm the superiority of a 5-day regimen of postoperative intravenous antibiotics over a 1-day regimen in preventing surgical site infections after surgery for lower extremity bone tumors that required an endoprosthesis. The 5-day regimen group had significantly more antibiotic-related complications. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01479283.

Extensile Anterior and Posterior Knee Exposure for Complete Synovectomy of Diffuse Tenosynovial Giant Cell Tumor (Pigmented Villonodular Synovitis).

Diffuse tenosynovial giant cell tumor (TGCT), also known as pigmented villonodular synovitis, is a benign, neoplastic disease of the synovium that can lead to joint destruction, osteoarthritis, and long-term morbidity1,2. Often, there is extra-articular involvement in the intercondylar notch and posterior soft tissues. A complete anterior and posterior synovectomy of the knee is indicated for treating diffuse TGCT when the anterior and posterior compartments of the knee joint are involved. Additionally, either an anterior or posterior synovectomy may be performed when the TGCT is limited to 1 compartment of the knee. Although an anterior synovectomy is relatively straightforward technically, a posterior synovectomy is challenging because of the presence of the neurovascular and muscular structures, which limit access, and because of the infrequency of the procedure. Description: The surgical technique for open anterior and posterior knee synovectomy is performed under 1 anesthetic via separate exposures with the patient initially supine and then prone. In cases of focal TGCT, in which both the anterior and posterior compartments are involved, either an anterior or posterior approach can be utilized in isolation to target the affected compartment. The anterior approach is performed via anteromedial parapatellar arthrotomy, with care to preserve the meniscal attachments and ligaments. Once the suprapatellar pouch is visualized, all tissue deep to the quadriceps muscle and tendon, extending around to the femoral periosteum, is excised en bloc. Attention is then turned to the undersurface of the patella, fat pad, distal aspect of the femur, and proximal aspect of the tibia. The tumor may be embedded within the fat pad and must be removed. Any tumor remnants within the medial or lateral gutter or beneath the menisci are excised with use of a standard or pituitary rongeur or curets. The quadriceps tendon, subcutaneous tissue, and skin are closed over a deep drain, and the patient is turned prone and re-prepared for the posterior approach. The posterior synovectomy utilizes an S-shaped incision either superolateral to inferomedial or superomedial to inferolateral, depending on the location of the TGCT. The popliteal artery and vein and the tibial and common peroneal nerves are identified, mobilized, and protected during retraction. This step requires ligating the geniculate and other small branches of the popliteal artery and vein. To expose the posterior femoral condyle, the medial and/or lateral heads of the gastrocnemius must be tagged and released by dividing the myotendinous origin from the posterior aspect of the femur at the proximal extent of the condyle. Alternatives: Although surgical resection is the primary treatment for TGCT, nonsurgical alternatives include radiation therapy (either external beam or radiosynoviorthesis) and the use of pharmacologic agents. Radiation therapy is associated with complications such as irreversible skin changes, arthrofibrosis, arthritis, osteonecrosis, and radiation-induced sarcoma1,2. Systemic agents such as tyrosine kinase inhibitors (e.g., nilotinib and imatinib) or agents targeting the CSF-1 (colony-stimulating factor-1) pathway (e.g., pexidartinib and emactuzumab) are active against TGCT. The agents are typically employed in recurrent, advanced, and unresectable situations in which surgical morbidity would outweigh the therapeutic benefit2. Aside from open synovectomy, arthroscopic synovectomy-usually anterior-has been utilized by some centers. Rationale: To our knowledge, there is no Level-I study indicating the superiority of 1 surgical technique over the other treatments for diffuse TGCT. Anterior arthroscopic synovectomy, in isolation, for diffuse TGCT has demonstrated recurrence rates as high as 92% to 94%1. Recent studies comparing anterior and posterior open and arthroscopic synovectomy have demonstrated mixed results, are limited by being retrospective, and are subject to selection bias because of the open synovectomy being selected for more extensive disease2,3. The mixed results may a result of variation in both tumor size and location about the knee joint2. The benefit of an open anterior and posterior synovectomy is that it can provide optimal exposure for large and extra-articular tumor masses that would not be accessible using an arthroscopic approach and allows for complete, gross total excision without morsellization of the tumor. The surgeon must be familiar and facile with vascular dissection techniques, even if the soft tissues surrounding the vascular structures are preserved as much as possible, in an effort to minimize postoperative edema4. Expected Outcomes: Open anterior and posterior synovectomy provides improved exposure for large and extra-articular tumor masses and has a 5-year recurrence-free survival of 29% to 33%5-7. Pain associated with diffuse TGCT has been demonstrated to improve in 59% of cases, with swelling reported to improve by 72% in patients following surgical intervention7. No significant difference has been reported when comparing open versus arthroscopic synovectomy in terms of arthritic progression, with 8% of patients progressing to a total knee arthroplasty at a mean follow-up of 40 months3. Important Tips: Careful preoperative planning is crucial: note all locations of posteriorly located tumor on magnetic resonance imaging and in relation to anatomic landmarks and neurovascular structures in order to guide dissection.It can be advantageous to have multiple blunt retractor options available when dissecting in tight spaces.Be prepared for vessel ligation with free ties, vessel clips, and additional clamps.The technical ability to dissect and mobilize the popliteal vessels is essential, but this step can be tedious.At the time of incision, preserve the integrity of the popliteal fascia to facilitate a good closure later, as this step avoids the herniation of tissues in the popliteal fossa. Because this fascial tissue is fragile, the use of a monofilament rather than braided suture in addition to the placement of far-near-near-far-type figure-of-8 sutures minimizes the risk of tearing the fascia during reapproximation.To ease retraction of the soft tissues, slightly flex the knee to relax the hamstring and other muscles and neurovascular structures. This will also reduce the risk of a postoperative nerve palsy.Although separate instruments for the anterior and posterior portions of the procedure are not necessary, separate drapes, gown, and gloves and other preoperative preparation should be readied in advance for the second portion of the procedure in order to save operative time. Acronyms & Abbreviations: PVNS = pigmented villonodular synovitisROM = range of motionMRI = magnetic resonance imagingGastroc = gastrocnemiusPDS = polydioxanone sutureCAM = controlled ankle motionASA = acetylsalicylic acid (aspirin).

Diagnostic accuracy of optical coherence tomography for surgical margin assessment of feline injection-site sarcoma.

The invasive, locally aggressive nature of feline injection-site sarcomas (FISSs) poses a unique challenge for surgeons to obtain complete margins with surgical excision. Optical coherence tomography (OCT), an imaging technology that uses light waves to generate real-time views of tissue architecture, provides an emerging solution to this dilemma by allowing fast, high-resolution scanning of surgical margins. The purpose of this study was to use OCT to assess surgical margins of FISS and to evaluate the diagnostic accuracy of OCT for detecting residual cancer using six evaluators of varying experience. Five FISSs were imaged with OCT to create a training set of OCT images that were compared with histopathology. Next, 25 FISSs were imaged with OCT prior to histopathology. Six evaluators of varying experience participated in a training session on OCT imaging after which each of the evaluators was given a dataset that included OCT images and videos to score on a scale from cancerous to non-cancerous. Diagnostic accuracy statistics were calculated. The overall sensitivity and specificity for classification of OCT images by evaluators were 78.9% and 77.6%, respectively. Correct classification rate of OCT images was associated with experience, while individual sensitivities and specificities had more variation between experience groups. This study demonstrates the ability of evaluators to correctly classify OCT images with overall low levels of experience and training and also illustrates areas where increased training can improve accuracy of evaluators in interpretation of OCT surgical margin images.

Osteonecrosis of the Femoral Head: an Updated Review of ARCO on Pathogenesis, Staging and Treatment.

Non-traumatic osteonecrosis of the femoral head (ONFH) usually affects adults younger than 50 years and frequently leads to femoral head collapse and subsequent arthritis of the hip. It is becoming more prevalent along with increasing use of corticosteroids for the adjuvant therapy of leukemia and other myelogenous diseases as well as management of organ transplantation. This review updated knowledge on the pathogenesis, classification criteria, staging system, and treatment of ONFH.

Diagnosis and Treatment of Femoral Head Osteonecrosis: A Protocol for Development of Evidence-Based Clinical Practice Guidelines.

INTRODUCTION: There are many treatment options for patients who have osteonecrosis of the femoral head (ONFH) and management strategies vary widely both among and within individual countries. Although many researchers have attempted to elucidate the optimal strategies for managing this disease, the lack of large-scale randomized control trials and the lack of agreement on disease staging have curtailed the development of clear-cut guidelines. MATERIALS AND METHODS: The Association Research Circulation Osseous (ARCO) group sought to address three questions for the management of patients who have ONFH: 1) What imaging studies are most sensitive and specific for the diagnostic evaluation of patients who have ONFH?; 2) What is the best treatment strategy for preventing disease progression in patients who have pre-collapse lesions?; and 3) What is the best treatment strategy for patients who have post-collapse disease? The Patient, Intervention, Comparison, and Outcome (PICO) format was used to formulate the search strategy for each research question. A systematic review will be performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. ARCO participants have been allocated to three groups, each representing one of the PICO questions. After qualitative and quantitative analysis of the data extracted from studies pertaining to each of the three research questions, a set of evidence-based clinical practice guidelines will be proposed for the management of patients who have ONFH. DISCUSSION: It is not always clear which treatment method is optimal for the management of ONFH. Thus, many surgeons have developed and performed various procedures based on patient-specific factors. As there is no consensus on the optimal treatment for various stages of disease, it was clear that developing evidence-based clinical practice guidelines would provide more structure and uniformity to management of these patients. Therefore, the results of this systematic review will lead to the development guidelines that may improve patient-care strategies and result in better outcomes for patients who have ONFH.

ARCO Consensus on the Pathogenesis of Non-traumatic Osteonecrosis of the Femoral Head.

Osteonecrosis of the femoral head (ONFH) is a devastating disease frequently leading to femoral head collapse and hip arthritis. Specifically, non-traumatic ONFH primarily affects young and middle-aged adults. Although compromised local circulation of the femoral head seems to be pathognomonic for the disease, the pathogenesis is perplexing and continues to be an area of scrutiny and research. Comprehension of the pathogenesis is of crucial importance for developing and guiding treatments for the disease. Therefore, we provide an up-to-date consensus on the pathogenesis of non-traumatic ONFH.

Levels of Urgency for Orthopaedic Procedures: Reliability and Adoption of a Consensus-driven Classification.

INTRODUCTION: The current COVID-19 disease pandemic has delayed nonurgent orthopaedic procedures to adequately care for those affected by the severe acute respiratory syndrome coronavirus 2, resulting in a backlog in orthopaedic surgical care. As the capacity for orthopaedic surgeries expands or contracts, allocation of limited resources in a manner that adequately reflects medical necessity and urgency is paramount. An orthopaedic surgery-specific prioritization schema with proven reliability is lacking. The primary aim of this study was to assess the reliability of a newly developed prioritization list used for the phased reinstatement of orthopaedic surgical procedures during the COVID-19 pandemic and afterward. The secondary aim was to report its implementation. METHODS: A consensus-based, orthopaedic surgery-specific, tiered prioritization list reflecting various levels of urgency was created by a committee of orthopaedic surgeons covering all subspecialties and representing academic, multispecialty, and private community practices. Reliability was tested for 63 randomized cases representing all orthopaedic subspecialties. Four raters evaluated the cases independently at two separate time points, at least one week apart. Fleiss kappa was used to assess intrarater and interrater agreement. Implementation were assessed by surveying both surgeons and the surgery scheduling administrative personnel at each surgical facility within a large health system for any adoption issues. RESULTS: Case distributions within tiers 1, 2, 3, and 4 were 35%, 14%, 27%, and 24%, respectively. Interrater agreement ranged from 0.63 (95% confidence interval [CI] 0.57 to 0.69) to 0.72 (95% CI 0.66 to 0.78) for the ratings. Intrarater reliability ranged from 0.62 to 1.0. The highest levels of agreement were in tiers 1, 4, and the subspecialties oncology and foot/ankle. The time from development to full scale adoption and implementation by all orthopaedic surgeons was rapid. DISCUSSION: This tiered prioritization list for orthopaedic procedures is both adoptable and reliable during the phased reinstatement of procedures during the COVID-19 pandemic and afterward. Further refinements may enhance utility. LEVELS OF EVIDENCE: Reliability study: Level I (Evid Based Spine Care J 2014 October;5(2):166. doi: 10.1055/s-0034-1394106).