Corticosteroid Injections within 2 weeks Following Knee Arthroscopy is Associated with Increased Infection Risk.

PURPOSE: We quantified the risk of 90-day postoperative infection following arthroscopy, stratified by specific time intervals of corticosteroid injection (CSI) postoperatively (0-2 weeks, 2-4 weeks, 4-6 weeks, and 6-8 weeks). METHODS: A national, all-payer database was queried. In the primary and secondary analyses, the main outcome was infection at 90-days. Infection was defined by documentation of a septic knee or surgical-site infection according to International Classification of Disease (ICD) Ninth Revision (9) and Tenth Revision (10) codes, and Current Procedure Terminology (CPT) codes. RESULTS: In the multivariable regression, the odds ratio (OR) of postoperative infection at 90-days was greater in the CSI injections within 0-<2 weeks (OR 3.31, 95% CI 1.85-5.92, P<0.001) and 2-<4 weeks (OR 2.72 95% CI 1.57-4.71, P=0.003) cohorts in comparison to the control group. When comparing CSI administered within 0-2 weeks to CSI administered within 2-4 weeks, there was a greater odds of postoperative infection (OR 2.50) at 90-days following arthroscopy. CONCLUSION: CSI given within 2 weeks following knee arthroscopy increases the risk of postoperative infection the greatest whereas CSI given with 4 weeks increases the risk but to a lesser degree.

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.

Synergistic effects of robotic surgery and IPACK nerve block on reduction of opioid consumption in total knee arthroplasty.

Background: There are numerous strategies to combat postoperative analgesia and expedite recovery after total knee arthroplasty (TKA). The purpose of this study was to determine opioid consumption, length of stay, and functional outcomes after robotic versus standard TKA in the setting of various regional pain modalities. Methods: A consecutive series of patients treated with unilateral primary robotic or standard TKA from January 2018-February 2021 were retrospectively identified. Regional pain modalities included peri-articular injection (PAI), adductor canal block (ACB), and infiltration between popliteal artery and capsule of knee (IPACK). Patient demographics, operative/perioperative variables, and postoperative function were recorded. Daily opiate consumption was calculated as morphine milligram equivalents (MME). Multivariate regression was performed to control for age, sex, and race. Results: After review, 283 patients (177 Females; 106 Males) were included. Robotic TKA patients received IPACK + ACB (36), while standard TKA patients received either ACB (45), IPACK + ACB (167), or PAI (35). Daily inpatient opioid consumption in the standard IPACK + ACB (p = 0.02) and robotic IPACK + ACB groups (p = 0.0001) was significantly lower compared to standard ACB. When combined with IPACK block, robotic procedures synergistically lowered opiate consumption (p = 0.004) compared to standard procedures and led to earlier discharge (p = 0.003). The robotic IPACK + ACB cohort also demonstrated improved early ambulation compared to standard ACB, (p = 0.05), whereas the same benefit was not seen for patients who received IPACK during standard TKA. Conclusions: The utilization of IPACK block decreases inpatient postoperative opioid requirements following TKA. Robotic TKA and IPACK block appeared to have a synergistic effect on opioid consumption and postoperative recovery.

Learning curve for active robotic total knee arthroplasty.

PURPOSE: Total Knee Arthroplasty (TKA) procedures incorporate technology in an attempt to improve outcomes. The Active Robot (ARo) performs a TKA with automated resections of the tibia and femur in efforts to optimize bone cuts. Evaluating the Learning Curve (LC) is essential with a novel tool. The purpose of this study was to assess the associated LC of ARo for TKA. METHODS: A multi-center prospective FDA cohort study was conducted from 2017 to 2018 including 115 patients that underwent ARo. Surgical time of the ARo was defined as Operative time (OT), segmented as surgeon-dependent time (patient preparation and registration) and surgeon-independent time (autonomous bone resection by the ARo). An average LC for all surgeons was computed. Complication rates and patient-reported outcome (PRO) scores were recorded and examined to evaluate for any LC trends in these patient related factors. RESULTS: The OT for the cases 10-12 were significantly quicker than the OT time of cases 1-3 (p < 0.028), at 36.5 ± 7.4 down from 49.1 ± 17 min. CUSUM and confidence interval analysis of the surgeon-dependent time showed different LCs for each surgeon, ranging from 12 to 19 cases. There was no difference in device related complications or PRO scores over the study timeframe. CONCLUSION: Active Robotic total knee arthroplasty is associated with a short learning curve of 10-20 cases. The learning curve was associated with the surgical time dedicated to the robotic specific portion of the case. There was no learning curve-associated device-related complications, three-dimensional component position, or patient-reported outcome scores. LEVEL OF EVIDENCE: Level II.

Safe and effective use of active robotics for TKA: Early results of a multicenter study.

BACKGROUND: A novel active robotic system for total knee arthroplasty (TKA) performs automated milling of bone surfaces. Study objectives were to assess system safety and effectiveness in a US population. METHODS: A multicenter clinical trial was conducted, following 115 patients for at least 6-months. A pre-defined list of robot-related adverse events was used to evaluate safety. Efficacy was assessed radiographically comparing planned versus achieved coronal limb alignment. RESULTS: No pre-defined adverse events occurred and postoperative limb alignment more than ±3° from plan occurred in 11.2 % of cases. CONCLUSION: Active robotics for TKA is safe and effective as demonstrated in this trial.

Active Robotic Total Knee Arthroplasty (TKA): Initial Experience with the TSolution One ® TKA System.

Several recent advances, including the use of robotic devices, have been explored to improve outcomes in total knee arthroplasty (TKA). The TSolution One ® Total Knee Application (THINK Surgical, Inc., Fremont, CA, USA) introduces an active robotic device that supports an open implant platform and CT-based preoperative planning workflow, and requires minimal surgeon intervention for making bone cuts. Our experience was part of a multi-center, prospective, non-randomized trial assessing the safety and effectiveness of this active robotic system for TKA. Each patient underwent a preoperative CT-scan, which was uploaded to proprietary planning software. The surgeon reviewed the software-generated 3D digital model, selected the appropriate implants and generated a final preoperative plan. Intra-operatively, a standard medial parapatellar approach was used. The leg was then rigidly attached to the robot via fixation pins, and registration markers were placed in the tibia and femur. Landmark registration was performed to inform the robot of the knee's position in space and to confirm the robot's ability to execute the preoperative plan. Next, the robot performed femoral and tibial cuts using a cutter in a sequential fashion along a defined cut-path. The robot was then removed from the operative field and the surgeon completed the procedure by removing marginal bone and performing final balancing and implantation in the usual fashion. The TSolution One® Total Knee Application is a computer-assisted device that potentially allows a surgeon to make more accurate cuts and to determine optimal implant position based on the patient's specific anatomy. It is the only active robotic system currently available. In this manuscript, we describe the operative technique and workflow involved in performing this surgery and offer insight on optimizing safety and efficiency as we introduce new technologies to the operating theater. We also present two cases performed by the senior author to further demonstrate technical aspects of the procedure.

Human ex vivo 3D bone model recapitulates osteocyte response to metastatic prostate cancer.

Prostate cancer (PCa) is the second leading cause of cancer deaths among American men. Unfortunately, there is no cure once the tumor is established within the bone niche. Although osteocytes are master regulators of bone homeostasis and remodeling, their role in supporting PCa metastases remains poorly defined. This is largely due to a lack of suitable ex vivo models capable of recapitulating the physiological behavior of primary osteocytes. To address this need, we integrated an engineered bone tissue model formed by 3D-networked primary human osteocytes, with conditionally reprogrammed (CR) primary human PCa cells. CR PCa cells induced a significant increase in the expression of fibroblast growth factor 23 (FGF23) by osteocytes. The expression of the Wnt inhibitors sclerostin and dickkopf-1 (Dkk-1), exhibited contrasting trends, where sclerostin decreased while Dkk-1 increased. Furthermore, alkaline phosphatase (ALP) was induced with a concomitant increase in mineralization, consistent with the predominantly osteoblastic PCa-bone metastasis niche seen in patients. Lastly, we confirmed that traditional 2D culture failed to reproduce these key responses, making the use of our ex vivo engineered human 3D bone tissue an ideal platform for modeling PCa-bone interactions.

Ex vivo replication of phenotypic functions of osteocytes through biomimetic 3D bone tissue construction.

Osteocytes, residing as 3-dimensionally (3D) networked cells in bone, are well known to regulate bone and mineral homeostasis and have been recently implicated to interact with cancer cells to influence the progression of bone metastases. In this study, a bone tissue consisting of 3D-networked primary human osteocytes and MLO-A5 cells was constructed using: (1) the biomimetic close-packed assembly of 20-25µm microbeads with primary cells isolated from human bone samples and MLO-A5 cells and (2) subsequent perfusion culture in a microfluidic device. With this 3D tissue construction approach, we replicated ex vivo, for the first time, the mechanotransduction function of human primary osteocytes and MLO-A5 cells by correlating the effects of cyclic compression on down-regulated SOST and DKK1 expressions. Also, as an example of using our ex vivo model to evaluate therapeutic agents, we confirmed previously reported findings that parathyroid hormone (PTH) decreases SOST and increases the ratio of RANKL and OPG. In comparison to other in vitro models, our ex vivo model: (1) replicates the cell density, phenotype, and functions of primary human osteocytes and MLO-A5 cells and (2) thus provides a clinically relevant means of studying bone diseases and metastases.

Hypoxic Three-Dimensional Cellular Network Construction Replicates Ex Vivo the Phenotype of Primary Human Osteocytes.

Osteocytes are deeply embedded in the mineralized matrix of bone and are nonproliferative, making them a challenge to isolate and maintain using traditional in vitro culture methods without sacrificing their inimitable phenotype. We studied the synergistic effects of two microenvironmental factors that are vital in retaining, ex vivo, the phenotype of primary human osteocytes: hypoxia and three-dimensional (3D) cellular network. To recapitulate the lacunocanalicular structure of bone tissue, we assembled and cultured primary human osteocytic cells with biphasic calcium phosphate microbeads in a microfluidic perfusion culture device. The 3D cellular network was constructed by the following: (1) the inhibited proliferation of cells entrapped by microbeads, biomimetically resembling lacunae, and (2) the connection of neighboring cells by dendrites through the mineralized, canaliculi-like interstitial spaces between the microbeads. We found that hypoxia synergistically and remarkably upregulated the mature osteocytic gene expressions of the 3D-networked cells, SOST (encoding sclerostin) and FGF23 (encoding fibroblast growth factor 23), by several orders of magnitude in comparison to those observed from two-dimensional and normoxic culture controls. Intriguingly, hypoxia facilitated the self-assembly of a nonproliferating, osteoblastic monolayer on the surface of the 3D-networked cells, replicating the osteoblastic endosteal cell layer found at the interface between native bone and bone marrow tissues. Our ability to replicate, with hypoxia, the strong expressions of these mature osteocytic markers, SOST and FGF23, is important since these (1) could not be significantly produced in vitro and (2) are new important targets for treating bone diseases. Our findings are therefore expected to facilitate ex vivo studies of human bone diseases using primary human bone cells and enable high-throughput evaluation of potential bone-targeting therapies with clinical relevance.

Incidental Asymptomatic Fibular Stress Fractures Presenting as Varus Knee Osteoarthritis: A Case Report.

Stress fractures are often missed, especially in unusual clinical settings. We report on 2 patients who presented to our orthopedic surgery clinic with incidental findings of asymptomatic proximal fibular tension side stress fractures in severe longstanding varus osteoarthritic knees. Initial plain films demonstrated an expansile deformity of the proximal fibular shaft, and differential diagnosis included a healed or healing fracture versus possible neoplasm. Magnetic resonance imaging with and without gadolinium was utilized to rule out the latter prior to planned total knee arthroplasty.

Ex vivo construction of human primary 3D-networked osteocytes.

A human bone tissue model was developed by constructing ex vivo the 3D network of osteocytes via the biomimetic assembly of primary human osteoblastic cells with 20-25µm microbeads and subsequent microfluidic perfusion culture. The biomimetic assembly: (1) enabled 3D-constructed cells to form cellular network via processes with an average cell-to-cell distance of 20-25µm, and (2) inhibited cell proliferation within the interstitial confine between the microbeads while the confined cells produced extracellular matrix (ECM) to form a mechanically integrated structure. The mature osteocytic expressions of SOST and FGF23 genes became significantly higher, especially for SOST by 250 folds during 3D culture. The results validate that the bone tissue model: (1) consists of 3D cellular network of primary human osteocytes, (2) mitigates the osteoblastic differentiation and proliferation of primary osteoblast-like cells encountered in 2D culture, and (3) therefore reproduces ex vivo the phenotype of human 3D-networked osteocytes. The 3D tissue construction approach is expected to provide a clinically relevant and high-throughput means for evaluating drugs and treatments that target bone diseases with in vitro convenience.