Meniscal extrusion consensus statement: A collaborative survey within the Meniscus International Network (MenIN) Study Group.

PURPOSE: The purpose of the present study was to perform a survey administered to members of the Meniscus International Network (MenIN) Study Group, seeking to delineate the most contentious aspects of meniscal extrusion classification and provide a foundation for new, more comprehensive definitions and treatments for these pathologies. METHODS: MenIN Study Group is a group of international experts treating and performing research on meniscus pathology and treatment. All MenIN Study Group members were asked to complete a survey aimed at establishing criteria for the optimal classification system for meniscal extrusion. Data obtained from the completed questionnaires were transferred into a spreadsheet and then analysed. All responses are presented as counts, percentages or means. RESULTS: Forty-seven (85.5%) MenIN Study Group members completed the survey and were included in this analysis. Key aspects recommended for inclusion in a comprehensive classification system for meniscal extrusion included laterality (93.6%), anatomical location (76.6%), patient age (76.6%), body mass index (BMI) (68.1%) and aetiology (68.1%). For classifying meniscal extrusion, 53.2% considered the distance in millimetres from the tibial plateau's outer margin as the most reliable measurement technique on imaging. Preferences for imaging modalities varied, with 44.7% favouring weight-bearing magnetic resonance imaging (MRI) and 36.2% opting for weight-bearing ultrasound due to its greater availability. Respondents advocated for a classification system addressing stability or progression of meniscal extrusion (66%), reducibility (53.2%), potential progression of knee osteoarthritis (OA) (83%), influencing treatment approaches (83%), a gradation system (83%), consideration of dynamic factors (66%), association with clinical outcomes and prognosis (76.6%) and investigation around centralization procedures (57.4%). CONCLUSIONS: In conclusion, the findings of this survey shed light on the global perspectives regarding meniscal extrusion classification. It was generally felt that a new classification of extrusion measured on MRI scans at the mid-tibial plateau should be developed, which considers factors such as laterality, anatomical location, age, BMI and aetiology. Additionally, the results support the integration of dynamic factors and clinical outcomes in MRI-based classifications to inform treatment approaches. LEVEL OF EVIDENCE: Level IV.

Inflammatory synovial biomarkers and state of the tibiofemoral joint in the post-surgical settings: a narrative review.

Background and Objective: Knee surgery attempts to restore the native biomechanics of the knee, improve stability, and decrease the progression of osteoarthritis (OA). However, despite improvements in surgical techniques, tissue degradation and OA are common after knee surgery, occurring in higher rates in surgical knees compared to non-surgical knees. The aim of this study is to analyze previous literature to determine which synovial fluid biomarkers contribute to knee tissue degradation and decrease patient outcomes in the post-surgical setting of the knee. Methods: A narrative review of relevant literature was performed in July 2023. Studies reporting on synovial biomarkers associated with the post-surgical knee were included. Key Content and Findings: The literature reported that proinflammatory synovial biomarkers cause cartilage degradation and turnover which eventually leads to OA. The associated biomarkers are typically present prior to physical symptoms so understanding which one's correlate to OA is important for potential therapeutic treatments in the future. Studying the preoperative, early postoperative, and late postoperative synovial biomarkers will allow physicians to develop an improved understanding of how these biomarkers progress and correlate to knee tissue degradation and OA. This understanding could lead to further developments into potential treatment options. Research into inhibiting or reversing these inflammatory biomarkers to slow the progression of knee tissue degradation has already begun and has reported some promising results but is currently limited in scope. Conclusions: Synovial fluid biomarkers in the post-surgical knee setting may contribute to decreased patient outcomes and the progression of knee tissue degradation. There is no current consensus on which of these biomarkers are the most detrimental or associated with decreased patient outcomes. With an improved understanding of the individual biomarkers, potential personalized therapeutic treatment could be used by physicians in the future to improve patient outcomes after surgery.

The effect of nonsteroidal anti-inflammatory drug use on soft tissue and bone healing in the knee: a systematic review.

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used to mitigate pain and inflammation associated with musculoskeletal conditions; however, there is conflicting data on the adverse effects of these drugs on tissue and bone healing. The objective of this study was to investigate the effect of NSAIDs on the healing of knee, soft tissue, and bone. Methods: A systematic literature search was conducted across PubMed/MEDLINE, Excerpta Medical Database (Embase)/Ovid, and the Cochrane Central Register of Controlled Trials databases. Clinical, animal, and in vitro studies on the effect of NSAIDs on knee healing were included. Risk of bias assessment was performed using the Cochrane bias assessment tool and Methodological Index for Non-Randomized Studies scoring system for included clinical studies, and the Systematic Review Center for Laboratory Animal Experimentation assessment tool for all included animal studies. General study population characteristics, interventions used, NSAIDs utilized, outcome measures, and study results were analyzed using descriptive statistics. Results: Fifteen articles met the inclusion criteria. Of the 15 studies, there were three clinical, ten animal, and two in vitro studies. In clinical studies, nonselective cyclooxygenase (COX) inhibitors and selective COX-2 inhibitors did not cause a significant increase in failure of anterior cruciate ligament (ACL) reconstructions or meniscal repairs with NSAID administration pre-, peri-, or post-operatively in comparison to placebo or no NSAID administration. Among animal studies assessing COX-2 inhibitor effects on soft tissue, healing was impaired (2/4), delayed but unaffected (1/4), or unaffected (1/4). In animal studies assessing COX-1 inhibitors, ligament healing was either increased (1/4), unaffected (2/4), or impaired (1/4). Meanwhile, administration of non-selective COX inhibitors in animals did not affect soft tissue (3/3) and cartilage (1/1) healing. Two in vitro studies identified a negative outcome on patellar tendon and ACL cell proliferation or viability after non-selective COX inhibition and variable results after selective COX-2 inhibition. Conclusions: Animal studies on postoperative NSAID use after knee surgery suggest that administration of selective and nonselective COX-2 inhibitors may impair healing of soft tissue, bone and tendon-to-bone; however, further clinical studies are needed to better characterize dose and duration dependent risks of NSAIDs.

Effect of anti-inflammatory treatments on patient outcomes and concentrations of inflammatory modulators in the post-surgical and post-traumatic tibiofemoral joint setting: a narrative review.

Background and Objective: There are several anti-inflammatory therapeutic options that can be used in the context of post-surgical and post-traumatic knee settings. Each of these options carries with it certain benefits, as well as potential issues depending on the duration and administration of each therapy. An understanding of how these anti-inflammatory drugs modulate various biomarkers of inflammation is also necessary in understanding how they can affect patient and objective outcomes following acute knee injury or surgery. This review covers the many traditional therapeutic options that have been used in treating knee injuries, as well as some natural therapeutics that have shown anti-inflammatory properties. Methods: A current review of the literature was conducted and synthesized into this narrative review. Key Content and Findings: Many traditional anti-inflammatory therapeutics have been shown to be beneficial in both post-traumatic and post-surgical tibiofemoral joint settings at reducing inflammation and improving patient outcomes. However, many of these treatments have risks associated with them, which becomes problematic with prolonged, repeated administration. Natural anti-inflammatory compounds may also have some benefit as adjunctive treatment options in these settings. Conclusions: There are multiple different therapeutic options that can be used in acute knee settings, but the specific mechanism of injury or surgical context should be weighed when determining the best clinical approach.

Acute Anterior Cruciate Ligament Reconstruction Performed Within 10 Days of Injury Does Not Increase Risk of Postoperative Arthrofibrosis: A Systematic Review and Meta-analysis.

BACKGROUND: The optimal timing of anterior cruciate ligament (ACL) reconstruction (ACLR) remains a controversial topic. Previous reviews have demonstrated that there are no differences between early and delayed ACLR; however, these studies have been limited by heterogeneous definitions of acute ACL injury. PURPOSE: To evaluate postoperative patient functional outcomes and risk for arthrofibrosis after acute arthroscopic ACLR performed ≤10 days after injury. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: A systematic review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using multiple medical databases. Inclusion criteria were studies that evaluated postoperative range of motion outcomes for patients undergoing ACLR ≤10 days after initial ACL injury. For included comparative studies comparing patient groups undergoing ACLR ≤10 days and patients undergoing "delayed" ACLR after ≥3 weeks of initial injury, quantitative analysis was performed to assess for differences in postoperative arthrofibrosis, reoperation rates, and patient-reported outcomes between groups. DerSimonian-Laird binary random-effects models were constructed to quantitatively describe the association between the ACLR time period and patient outcomes by generating effect estimates in the form of odds ratios with 95% CIs. Qualitative analysis was performed to describe variably reported patient outcomes and the risk of arthrofibrosis after ACLR for noncomparative studies. RESULTS: Screening yielded 6 full-text articles with 448 patients who underwent ACLR (296 ACLR <10 days, 152 ACLR >3 weeks), with a pooled mean age of 28.1 years. For studies amenable to quantitative analysis, there were no significant differences between ACLR performed ≤10 days and ACLR performed at the 3-week point or after in terms of postoperative stiffness (3 studies; odds ratio, 1.27; P = .508), Tegner scores (2 studies; mean difference, -0.056; P = .155), or reoperation for stiffness (3 studies; odds ratio, 0.869; P = .462). The overall incidence of postoperative arthrofibrosis after 12 months of follow-up was 11 of 296 (3.7%) for ACLRs performed ≤10 days versus 6 of 152 (3.9%) for those performed at the 3-week point or after. CONCLUSION: ACLR performed ≤10 days after the inciting injury does not increase the risk of postoperative arthrofibrosis and demonstrates similar patient-reported outcomes compared with ACLR performed at the 3-week point or after.

Anterior Referencing versus Posterior Referencing in Primary Total Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials.

(1) Background: The purpose of this study was to perform a systematic review and meta-analysis of studies comparing clinical and radiographic outcomes between anterior referencing (AR) and posterior referencing (PR) systems in total knee arthroplasty (TKA). (2) Methods: This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, MEDLINE, Scopus, and Cochrane Central databases were searched in August 2022. Data extracted for quantitative analysis included the Knee Society Score (KSS), the Western Ontario and McMaster University (WOMAC) index, knee ROM, posterior condylar offset (PCO), and the posterior condylar offset ratio (PCOR). The methodological quality of the included studies was assessed using the Modified Newcastle-Ottawa Quality Assessment. Randomized controlled trials were assessed with version 2 of the risk of bias tool (RoB2), recommended by the Cochrane Collaboration. (3) Results: For the meta-analysis, five comparative studies met the eligibility criteria. There were 584 patients in all, 294 of whom had AR TKA and 290 of whom had PR TKA. Three studies with 181 and 179 cases in the AR and PR groups, respectively, had reported preoperative KSS. A statistically significant difference was found favoring the PR group. (p = 0.01). The same cases' postoperative range of motion was documented, and a statistically significant difference was discovered in favor of the AR group. Postoperative PCO was described in four studies in 243 and 241 cases in the AR and PR TKA groups, respectively, and a statistically significant difference was found with a higher postoperative PCO in the PR group (p = 0.003). Postoperative PCOR was calculated in two studies in the same cases in the AR and PR TKA groups and a statistically significant difference was found with a higher postoperative PCOR in the PR group (p = 0.002). (4) Conclusion: Anterior referencing for TKA may result in improved knee ROM postoperatively, while posterior referencing may produce larger PCO and PCOR on postoperative imaging. However, no significant differences were noted in clinical outcomes between the AR and PR groups at final follow-up.

A Minimally Invasive Technique for Harvesting Quadriceps Tendon Autograft With a Bone Plug for Anterior Cruciate Ligament Reconstruction.

Anterior cruciate ligament reconstruction (ACLR) with quadriceps tendon (QT) was first described decades ago. Recent studies have demonstrated superior graft characteristics (diameter, strength, and stiffness) and reduced postoperative morbidity. However, limited instrumentation options currently available to surgeons allow for minimally invasive QT harvest with a bone plug. As an alternative to traditional QT harvest techniques, we describe a surgical technique allowing for minimally invasive QT autograft harvest with a bone plug (QuadVantage Technologies, Inc). This approach can offer technical advantages, including efficiency of graft harvest, reproducibility of procedure, and more consistent graft sizes.

Perioperative Gabapentin May Reduce Opioid Requirement for Early Postoperative Pain in Patients Undergoing Anterior Cruciate Ligament Reconstruction: A Systematic Review of Randomized Controlled Trials.

PURPOSE: To evaluate the efficacy of perioperative gabapentin or pregabalin treatment on postoperative pain and opioid requirement reduction in patients undergoing anterior cruciate ligament reconstruction (ACLR). METHODS: A systematic review of randomized control trials was conducted evaluating the effect of gabapentin or pregabalin on postoperative pain and opioid requirement for patients undergoing ACLR. The primary outcomes assessed were postoperative pain scores and opioid requirements. Secondary outcomes were complications, side effects, dosage, and timing of intervention. RESULTS: The initial search query identified 151 studies and 6 studies were included after full-text articles were reviewed. Three studies investigated the use of gabapentin and three studies investigated pregabalin. All three gabapentin studies reported significantly decreased or equivalent pain scores while also significantly reducing or removing total opioid consumption compared to control groups. Pregabalin demonstrated inconsistent efficacy for pain control and opioid consumption parameters across three studies. One study (pregabalin, n = 1) reported significantly increased incidence of dizziness with pregabalin compared to placebo. CONCLUSIONS: There is moderate evidence demonstrating that preoperative gabapentin may be safe and effective in reducing postoperative pain and opioid consumption after ACLR. Gabapentin may be considered when employed as part of a multimodal analgesia regimen; however, the optimal protocol has yet to be determined. Currently, there is limited evidence demonstrating the efficacy of pregabalin on pain and opioid consumption in the setting of ACLR. LEVEL OF EVIDENCE: Level I, systematic review of Level I Studies.

Preclinical Use of FGF-18 Augmentation for Improving Cartilage Healing Following Surgical Repair: A Systematic Review.

OBJECTIVE: To evaluate the efficacy of fibroblast growth factor-18 (FGF-18) augmentation for improving articular cartilage healing following surgical repair in preclinical (in vivo) animal models. DESIGN: A systematic review was performed evaluating the efficacy of FGF-18 augmentation with cartilage surgery compared with cartilage surgery without FGF-18 augmentation in living animal models. Eligible intervention groups were FGF-18 treatment in conjunction with orthopedic procedures, including microfracture, osteochondral auto/allograft transplantation, and cellular-based repair. Outcome variables were: International Cartilage Repair Society (ICRS) score, modified O'Driscoll histology score, tissue infill score, qualitative histology, and adverse events. Descriptive statistics were recorded and summarized for each included study. RESULTS: In total, 493 studies were identified and 4 studies were included in the final analysis. All studies were randomized controlled trials evaluating in vivo use of recombinant human FGF-18 (rhFGF-18). Animal models included ovine (n = 3) and equine (n = 1), with rhFGF-18 use following microfracture (n = 3) or osteochondral defect repair (n = 1). The rhFGF-18 was delivered via intra-articular injection (n = 2), collagen membrane scaffold (n = 1), or both (n = 1). All studies reported significant, positive improvements in cartilage defect repair with rhFGF-18 compared with controls based on ICRS score (n = 4), modified O'Driscoll score (n = 4), tissue infill (n = 3), and expression of collagen type II (n = 4) (P < 0.05). No adverse events were reported with the intra-articular administration of this growth factor, indicating short-term safety and efficacy of rhFGF-18 in vivo. CONCLUSION: This systematic review provides evidence that rhFGF-18 significantly improves cartilage healing at 6 months postoperatively following microfracture or osteochondral defect repair in preclinical randomized controlled trials.

Self-Assembly Culture Model for Engineering Musculoskeletal Tissues.

The goal of a self-assembly tissue engineering is to create functional tissue following a natural cell-driven process that mirrors natural development. This approach to tissue engineering has tremendous potential for the development of reparative strategies to treat musculoskeletal injuries and diseases, especially for articular cartilage which has poor regenerative capacity. Additionally, many bioengineering and culture methods fail to maintain the chondrocyte phenotype and contain the correct matrix composition in the long term. Existing cartilage-engineering approaches have been developed, but many approaches involve complicated culture techniques and require foreign substances and biomaterials as scaffolds. While these scaffold-based approaches have numerous advantages, such as an instant or rapid creation of biomechanical properties, they frequently result in dedifferentiation of cells in part, due to the adherence to foreign scaffold materials. In this chapter, we describe a novel approach of developing a scaffold-less cartilage-like biomaterial, using the simple principle that cells at high density bear a capacity to coalesce when they cannot attach to any culture substrate. We refer to the biomaterial formed as a cartilage tissue equivalent or CTA and have published to describe their characteristics and utility in high-throughput drug screening. The method is described to generate reproducible cartilage analogs using a specialized high-density suspension culture technique using a hydrogel poly-2-hydroxyethyl methacrylate (polyHEMA) coating of a culture dish. We have demonstrated that this approach can rapidly form biomass of chondrocytes that over time becomes very synthetically active producing a cartilage-like extracellular matrix that closely mimics the biochemical and biomechanical characteristics of native articular cartilage. The culture approach can also be used to form CTA from other than articular cartilage-derived chondrocytes as well as mesenchymal stem cells (MSCs) (while differentiating MSCs into chondrocytes). Some of the advantages are phenotype stability, reproducible CTA size, and biomechanical and biochemical characteristics similar to natural cartilage.

Biomechanical comparison of anterior cruciate ligament reconstruction fixation methods and implications on clinical outcomes.

Anterior cruciate ligament reconstruction (ACLR) is one of the more common surgeries encountered by orthopaedic surgeons, which has its inherent challenges due to the complex anatomy and biomechanical properties required to reproduce the function and stability of the native ACL. Multiple biomechanical factors from graft choice and tunnel placement to graft tensioning and fixation methods are vital in achieving a successful clinical outcome. Common methods of ACLR graft fixation in both the primary and revision setting are classified into compression/interference, suspensory, or hybrid fixation strategies with multiple adjunct methods of fixation. The individual biomechanical properties of these implants are crucial in facilitating early post-operative rehabilitation, while also withstanding the shear and tensile forces to avoid displacement and early graft failure during graft osseointegration. Implants within these categories include the use of interference screws (IFSs), as well as suspensory fixation with a button, posts, surgical staples, or suture anchors. Outcomes of comparative studies across the various fixation types demonstrate that compression fixation can decrease graft-tunnel motion, tunnel widening, and graft creep, at the risk of damage to the graft by IFSs and graft slippage. Suspensory fixation allows for a minimally invasive approach while allowing similar cortical apposition and biomechanical strength when compared to compression fixation. However, suspensory fixation is criticized for the risk of tunnel widening and increased graft-tunnel motion. Several adjunct fixation methods, including the use of posts, suture-anchors, and staples, offer biomechanical advantages over compression or suspensory fixation methods alone, through a second form of fixation in a second plane of motion. Regardless of the method or implant chosen for fixation, technically secure fixation is paramount to avoid displacement of the graft and allow for appropriate integration of the graft into the bone tunnel. While no single fixation technique has been established as the gold standard, a thorough understanding of the biomechanical advantages and disadvantages of each fixation method can be used to determine the optimal ACLR fixation method through an individualized patient approach.

Anatomy of the anterior cruciate ligament and the common autograft specimens for anterior cruciate ligament reconstruction.

A thorough understanding of the anatomical properties of the native anterior cruciate ligament (ACL), as well as the native specimens that are most commonly considered as viable autograft choices for anterior cruciate ligament reconstruction (ACLR), is warranted for continuing to pursue the best-possible graft choice for patients undergoing ACLR. While a wide variety of graft choices remain available to the operating surgeon, choosing the correct graft choice remains a consideration and discussion with patients on the pros and cons of each option. This article combines a review of the current literature on the quantitative and qualitative anatomy of the native ACL and common autograft specimens with the expert consensus of the senior author on the surgically-pertinent anatomy of these structures. The purpose of this article is to review the anatomy pertaining to the native ACL, along with the distal anatomy of the hamstring tendons, patellar tendon and quadriceps tendon (QT). Multiple tendinous and ligamentous structures exist around the knee that serve as viable candidates for use as autologous grafts for ACLR, and the anatomy of these distal extents of these structures are discussed thoroughly, including bony attachments, quantitative and relational anatomy, cross sectional area, and histological features of these structures.

Evolution of anterior cruciate ligament reconstruction & graft choice: a review.

The surgical treatment of anterior cruciate ligament (ACL) injuries dates back over 100 years from the present day [2022]. While open repair of the torn ACL was popularized in the early 1900s, the first ACL reconstructions utilized the fascia lata as a graft and other extra-articular stabilizing techniques. The first free tendon graft reported for ACL reconstructions was the quadriceps tendon (QT) in the 1930s, followed by the hamstrings tendon (HT), and then the patellar tendon. With improved understanding of the ACL anatomy and biomechanics and the invention of the arthroscope, ACL reconstruction evolved from open procedures to arthroscopic. Similarly, with the help of many surgeon-scientists who reported patient outcomes following ACL reconstruction with various techniques, graft choice evolved with the hamstrings and patellar tendon grafts becoming the dominant and preferred choice of both surgeons and patients. In present day, we see a resurgence of one of the original grafts reported, the QT, as well as primary ACL repair. Future research will result in continued advancements of ACL surgical techniques and graft harvesting, which will allow the orthopedic community (including patients and surgeons) to benefit from such innovations and advanced technologies.

Biomarkers for Osteoarthritis Diseases.

Growing evidence has revealed the pivotal role of inflammatory biomarkers in the pathogenesis of osteoarthritis. There is significant interest in the prognostic value of select biomarkers, given the potential for early identification and treatment of patients at risk of osteoarthritis prior to the development of irreversible clinical disease. Clinical trials of novel therapeutics that disrupt the inflammatory pathways of osteoarthritis are also ongoing. The purpose of this review is to summarize the current literature on key biomarkers within the context of osteoarthritis pathogenesis, clinical symptom development, and treatment capabilities. Multiple recent studies have established biomarkers that signal the existence of osteoarthritis pathology and the development of clinical symptomology. However, prior to implementation in clinical practice, additional research is required to precisely define the prognostic value for numerous biomarkers and standardize their measurement. Biomarker-driven investigations represent a promising avenue for the early diagnosis and treatment of osteoarthritis.

Femur Length is Correlated with Isometric Quadriceps Strength in Post-Operative Patients.

BACKGROUND: Few existing studies have examined the relationship between lower extremity bone length and quadriceps strength. PURPOSE/HYPOTHESIS: To evaluate the relationship between lower extremity, tibia and femur lengths, and isometric quadriceps strength in patients undergoing knee surgery. The null hypothesis was that there would be no correlation between lower extremity length and isometric quadriceps strength. STUDY DESIGN: Cross-sectional study. METHODS: Patients with full-length weightbearing radiographs that underwent isometric quadriceps strength testing after knee surgery were included. Using full-length weightbearing radiographs, limb length was measured from the ASIS to the medial malleolus; femur length was measured from the center of the femoral head to the joint line; tibia length was measured from the center of the plateau to the center of the plafond. Isometric quadriceps strength was measured using an isokinetic dynamometer. Pearson's correlation coefficient was used to report the correlation between radiographic limb length measurements. A Bonferroni correction was utilized to reduce the probability of a Type 1 error. RESULTS: Forty patients (26 males, 14 females) with an average age of 25.8 years were included. The average limb, femur, and tibia lengths were not significantly different between operative and non-operative limbs (p>0.05). At an average of 5.8±2.5 months postoperatively, the peak torque (156.6 vs. 225.1 Nm), average peak torque (151.6 vs. 216.7 Nm), and peak torque to bodyweight (2.01 vs 2.89 Nm/Kg) were significantly greater in the non-surgical limb (p<0.01). Among ligament reconstructions there was a significant negative correlation between both limb length and strength deficit (r= -0.47, p=0.03) and femur length and strength deficit (r= -0.51, p=0.02). The average strength deficit was 29.6% among the entire study population; the average strength deficit was 37.7% among knee ligament reconstructions. For the non-surgical limb, femur length was significantly correlated with peak torque (r = 0.43, p = 0.048). CONCLUSION: Femur length was significantly correlated with the isometric quadriceps peak torque for non-surgical limbs. Additionally, femur length and limb length were found to be negatively correlated with quadriceps strength deficit among ligament reconstruction patients. A combination of morphological features and objective performance metrics should be considered when developing individualized rehabilitation and strength programs.

Posterior Tibial Slope in Patients With Torn ACL Reconstruction Grafts Compared With Primary Tear or Native ACL: A Systematic Review and Meta-analysis.

Background: Increased posterior tibial slope (PTS) is a risk factor for anterior cruciate ligament (ACL) rupture and failure of ACL reconstruction (ACLR) grafts. Purpose: The purpose was to conduct a systematic review of literature on PTS measurements and to conduct a meta-analysis of comparable PTS measurements based on a patient's ACL status. It was hypothesized that patients with torn ACLR grafts would have significantly larger medial and lateral PTS compared with patients with native ACLs or those who underwent primary ACLR. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included were studies that reported medial and/or lateral PTS measurements, those that reported PTS measurements based on ACL status (ie, intact ACL, primary ACL tear, failed ipsilateral ACLR, or revision ACLR), and those that reported their specific PTS measurement technique. Average PTS measurements, measurement location (medial or lateral tibial plateau) and technique, imaging modality used, and ACL status were extracted from each study. Data were pooled using DerSimonian and Laird random-effects models, and results were compared using the Altman interaction test. Results: The literature search identified 1705 studies, of which 82 (N = 12,971 patients) were included. There were 4028 patients in the intact ACL group (31%), 7405 in the primary ACLR group (57%), and 1538 in the failed ACLR group (12%). Measurements were obtained from lateral radiographs in 31 studies (38%), from magnetic resonance imaging in 47 studies (57%), and from computed tomography in 4 studies (5%). The failed ACLR group had a significantly larger lateral PTS (9.55°; 95% CI, 8.47°-10.63°) than either the primary ACL tear (7.13°; 95% CI, 6.58°-7.67°) or intact ACL (5.57°; 95% CI, 5.03°-6.11°) groups (P < .001 for both). The failed ACLR group also had a significantly larger medial PTS (9.05°; 95% CI, 7.80°-10.30°) than the primary (6.24°; 95% CI, 5.71°-6.78°) or intact ACL (6.28°; 95% CI, 5.21°-7.35°) groups (P < .001 for both). Conclusion: Both lateral and medial PTS measurements were greater in patients who had failed previous ACLR than those with a primary ACL tear or an intact native ACL. The lateral PTS of patients with primary ACL tears was greater than those with an intact native ACL.

Improved Accuracy of Coronal Alignment Can Be Attained Using 3D-Printed Patient-Specific Instrumentation for Knee Osteotomies: A Systematic Review of Level III and IV Studies.

PURPOSE: To evaluate the accuracy and precision of postoperative coronal plane alignment using 3D-printed patient-specific instrumentation (PSI) in the setting of proximal tibial or distal femoral osteotomies. METHODS: A systematic review evaluating the accuracy of 3D-printed PSI for coronal plane alignment correcting knee osteotomies was performed. The primary outcomes were accuracy of coronal plane limb alignment correction and number of correction outliers. Secondary variables were duration of surgery, number of intraoperative fluoroscopic images, complications, cost, and clinical outcomes (as applicable). RESULTS: Ninety-three studies were identified, and 14 were included in the final analysis. Overall, mean postoperative deviation from target correction ranged from 0.3° to 1° for all studies using hip-knee angle measurements and 2.3% to 4.9% for all studies using weight-bearing line measurements. The incidence of correction outliers was assessed in 8 total studies and ranged from 0 to 25% (total n = 10 knees) of patients corrected with 3D-printed PSI. Osteotomies performed with 3D-printed cutting guides or wedges demonstrated significantly shorter operative times (P < .05) and fewer intraoperative fluoroscopic images (P < .05) than control groups in four case control studies. CONCLUSION: Patients undergoing distal femoral osteotomy or proximal tibial osteotomy procedures with 3D-printed patient-specific cutting guides and wedges had highly accurate coronal plane alignment with a low rate of outliers. Patients treated with 3D printed PSI also demonstrated significantly shorter operative times and decreased intraoperative fluoroscopy when compared to conventional techniques. LEVEL OF EVIDENCE: Level IV, systematic review of Level III-IV studies.

Acute Intervention With Selective Interleukin-1 Inhibitor Therapy May Reduce the Progression of Posttraumatic Osteoarthritis of the Knee: A Systematic Review of Current Evidence.

PURPOSE: To evaluate the efficacy of selective interleukin (IL)-1 inhibitor therapy in the reduction of posttraumatic osteoarthritis (PTOA) progression following knee ligament or meniscal injury. METHODS: A systematic review was conducted evaluating the disease-modifying efficacy of selective IL-1 inhibition in the setting of knee PTOA. RESULTS: The literature search identified 364 articles and 11 studies were included (n = 10 preclinical, n = 1 clinical). Drug delivery in preclinical studies was administered using IL-1Ra-encoded helper-dependent adenovirus particles (n = 3), synovial cells transfected with an IL-1Ra-encoded retroviral vector (n = 3), or varying chemical compositions of nonviral microcapsule gene carriers (n = 4). Intervention with selective IL-1 inhibitor therapy within 2 weeks of injury provided the greatest protective benefits in reducing the progression of PTOA regardless of drug delivery methodology in preclinical models. The majority of studies reported significantly better cartilage integrity and reduction in lesion size in animals treated with gene therapy with the greatest effects seen in those treated within 5 to 7 days of injury. CONCLUSIONS: Early intervention with selective IL-1 inhibitor therapy were effective in reducing proinflammatory IL-1ß levels in the acute and subacute phases following traumatic knee injury in preclinical animal model studies, while significantly reducing cartilage damage, lesion size, and PTOA progression at short-term follow-up. However, it was found that the effect of these therapies diminished over time. CLINICAL RELEVANCE: Acute, intra-articular injection of selective IL-1 inhibitors may reduce PTOA progression, supporting the need for additional basic and clinical investigation.