High Accuracy of Intra-articular Needle Position during Anterior Landmark Guided Glenohumeral Injections.

OBJECTIVES: Image-guided ultrasound or fluoroscopic glenohumeral injections have high accuracy rates, but require training, equipment, cost, and radiation exposure (fluoroscopy). In contrast, landmark-guided glenohumeral injections do not require additional subspecialist referral or equipment. An optimal technique would be safe, accurate, and have few barriers to implementation. The purpose of this study was to define the accuracy of glenohumeral needle placement via an anterior landmark-guided approach as assessed by direct arthroscopic visualization. METHODS: A consecutive series of adult patients undergoing shoulder arthroscopy in the beach chair position were included in this study. Demographic and procedural data were collected. Time required to perform the injection, precise location of the needle-tip, and factors that affected accuracy of injection were also assessed. RESULTS: A standardized anterior landmark-guided glenohumeral joint injection was performed in the operating room prior to surgery and location of the needle tip was documented by arthroscopic visualization with a low complication profile and few barriers to implementation. A total of 81 patients were enrolled. Successful intra-articular glenohumeral needle placement by Sports Medicine and Shoulder/elbow fellowship trained orthopaedic surgeons was confirmed in 93.8% (76/81) of patients. Average time to complete the procedure was 24.8 seconds. There were no patient-related variables associated with non-intra-articular injection in the cohort. CONCLUSIONS: This study demonstrated a technique of anterior landmark-guided glenohumeral injection has an accuracy of 93.8% and requires less than 30 seconds to perform. This method is safe, yields similar accuracy to image-guided procedures with improved cost-and time-efficiency, and less radiation exposure. No patient-related factors were associated with inaccurate needle placement. Anterior landmark-guided glenohumeral injections may be utilized with confidence by providers in the clinical setting. LEVEL OF EVIDENCE: Level 5.

Augmented Ulnar Collateral Ligament Repair With Structural Bioinductive Scaffold: A Biomechanical Study.

BACKGROUND: Elbow ulnar collateral ligament (UCL) repair with suture brace augmentation shows good time-zero biomechanical strength and a more rapid return to play compared with UCL reconstruction. However, there are concerns about overconstraint or stress shielding with nonabsorbable suture tape. Recently, a collagen-based bioinductive absorbable structural scaffold has been approved by the Food and Drug Administration for augmentation of soft tissue repair. PURPOSE/HYPOTHESIS: This study aimed to assess the initial biomechanical performance of UCL repair augmented with this scaffold. We hypothesized that adding the bioinductive absorbable structural scaffold to primary UCL repair would impart additional time-zero restraint to the valgus opening. STUDY DESIGN: Controlled laboratory study. METHODS: Eight cadaveric elbow specimens-from midforearm to midhumerus-were utilized. In the native state, elbows underwent valgus stress testing at 30o, 60o, and 90o of flexion, with a cyclical valgus rotational torque. Changes in valgus rotation from 2- to 5-N·m torque were recorded as valgus gapping. Testing was then performed in 4 states: (1) native intact UCL-with dissection through skin, fascia, and muscle down to an intact UCL complex; (2) UCL-transected-distal transection of the ligament off the sublime tubercle; (3) augmented repair with bioinductive absorbable scaffold; and (4) repair alone without scaffold. The order of testing of repair states was alternated to account for possible plastic deformation during testing. RESULTS: The UCL-transected state showed the greatest increase in valgus gapping of all states at all flexion angles. Repair alone showed similar valgus gapping to that of the UCL-transected state at 30° (P = .62) and 60° of flexion (P = .11). Bioinductive absorbable scaffold-augmented repair showed less valgus gapping compared with repair alone at all flexion angles (P = .021, P = .024, and P = .024 at 30°, 60°, and 90°, respectively). Scaffold-augmented repair showed greater gapping compared with the native state at 30° (P = .021) and 90° (P = .039) but not at 60° of flexion (P = .059). There was no difference when testing augmented repair or repair alone first. CONCLUSION: UCL repair augmented with a bioinductive, biocomposite absorbable structural scaffold imparts additional biomechanical strength to UCL repair alone, without overconstraint beyond the native state. Further comparative studies are warranted. CLINICAL RELEVANCE: As augmented primary UCL repair becomes more commonly performed, use of an absorbable bioinductive scaffold may allow for improved time-zero mechanical strength, and thus more rapid rehabilitation, while avoiding long-term overconstraint or stress shielding.

An All-Suture-Based Technique for Meniscal Repair Is Cost-Effective in Comparison to Partial Meniscectomy for Horizontal Cleavage Tears.

Purpose: To determine the cost-effectiveness of meniscal repair (MR) using an all-suture-based technique when compared to partial meniscectomy (PM) for horizontal cleavage tears (HCTs) from a payor's perspective in the United States. Methods: A state-transition model and cost-utility analysis were developed from a US payor's perspective to project treatment costs and quality-adjusted life-years (QALYs) in a cohort of 35-year-old patients without osteoarthritis at baseline and presenting with either a lateral or medial HCT. Two outpatient costing perspectives were used, namely ambulatory surgical centers (ASCs) and hospitals. The state-transition model had 7 health states with transition probabilities, costs, and utilities obtained from the existing literature. Cost-effectiveness was assessed using a willingness-to-pay threshold of $100,000/QALY, and sensitivity analysis considered the effects of parameter uncertainty on model results. MR failure rates were focused on an all-suture-based technique; however, in a separate scenario, this study considered effectiveness data from various MR techniques and devices. Results: MR dominated PM over a lifetime horizon, increasing QALYs by 0.43 per patient and decreasing the cost by $12,227 per patient within a hospital setting (and by $12,570 within an ASC). MR with an all-suture-based technique continued to be the dominant treatment when age at primary treatment was varied between 30 and 60 years. Sensitivity analysis showed that MR was not cost-effective in year 1, was cost-effective from year 2, and was cost-saving from year 6 onward from both ASC and hospital perspectives. Probabilistic sensitivity analysis found that MR was cost-effective over a lifetime horizon in 99% of 10,000 iterations on base-case analysis. Conclusions: Using a lifetime horizon, this study found that from a payor's perspective, MR is a cost-saving intervention when compared with PM in patients with an HCT. Level of Evidence: Level III, economic analysis.

High Tibial Osteotomy in Knee Reconstruction and Joint Preservation.

High tibial osteotomy is a dynamic operation, used as an effective procedure in both joint preservation and knee stability. Applications and indications are expanding, with good results in the treatment of malalignment associated with arthrosis, knee instability, meniscus deficiency or transplants, and/or cartilage restoration. Appropriate patient selection and preoperative planning are critical to achieving good outcomes after surgery. Coronal and sagittal plane corrections made through the proximal tibia can effectively alter joint mechanics creating a more favorable environment for cartilage, meniscus, and ligamentous structures about the knee. Advancing techniques and technologies have allowed for more precise planning and execution of osteotomies.

Infra-patellar fat pad-derived mesenchymal stem cells maintain their chondrogenic differentiation potential after arthroscopic harvest with blood-product supplementation.

PURPOSE: Mesenchymal stem cells/medicinal signaling cells (MSCs) possess therapeutic potential and are used in regenerative orthopaedics. The infra-patellar fat pad (IFP) is partially resected during knee arthroscopy (KASC) and contains MSCs. Heat, irrigation, and mechanical stress during KASC may decrease MSC's therapeutic potential. This study assessed MSCs' regenerative potential after arthroscopic IFP harvest and potential effects of two blood products (BP) (platelet-rich plasma (PRP), hyperacute serum (HAS)) on MSCs' viability and chondrogenic differentiation capacity. METHODS: IFP was arthroscopically harvested, isolated, and counted (n = 5). Flow cytometry was used to assess cell viability via staining with annexin V/7-AAD and stemness markers via staining for CD90, CD73, and CD105. MSCs were incubated with blood products, and metabolic activity was determined via an XTT assay. Deposition of cartilage extracellular matrix was determined in histologic sections of chondrogenically differentiated 3D pellet cultures via staining with Alcian Blue. Expression of cartilage-specific genes (SOX9, MMP3/13, ACAN, COL1/2) was analyzed via quantitative PCR. RESULTS: MSC isolation from IFP yielded 2.66*106 ± 1.49*106 viable cells from 2.7 (0.748) g of tissue. MSC markers (CD 90/105/73) were successfully detected and annexin V staining showed 81.5% viable cells. XTT showed increased metabolic activity. Within the BP groups, this increase was significant (days 0-14, p < 0.05). PCR showed expression of cartilage-specific genes in each group. COL2 (p < 0.01) as well as ACAN (p < 0.001) expression levels were significantly higher in the HAS group. Histology showed successful differentiation. CONCLUSION: Arthroscopic harvest of IFP-MSCs yields sufficient cells with maintained regenerative potential and viability. Blood products further enhance MSCs' viability.

Experts Achieve Consensus on a Majority of Statements Regarding Platelet-Rich Plasma Treatments for Treatment of Musculoskeletal Pathology.

PURPOSE: To establish consensus statements on platelet-rich plasma (PRP) for the treatment of musculoskeletal pathologies. METHODS: A consensus process on the treatment of PRP using a modified Delphi technique was conducted. Thirty-five orthopaedic surgeons and sports medicine physicians participated in these consensus statements on PRP. The participants were composed of representatives of the Biologic Association, representing 9 international orthopaedic and musculoskeletal professional societies invited due to their active interest in the study of orthobiologics. Consensus was defined as achieving 80% to 89% agreement, strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. RESULTS: There was consensus on 62% of statements about PRP. CONCLUSIONS: (1) PRP should be classified based on platelet count, leukocyte count, red blood count, activation method, and pure-plasma versus fibrin matrix; (2) PRP characteristics for reporting in research studies are platelet count, leukocyte count, neutrophil count, red blood cell count, total volume, the volume of injection, delivery method, and the number of injections; (3) the prognostic factors for those undergoing PRP injections are age, body mass index, severity/grade of pathology, chronicity of pathology, prior injections and response, primary diagnosis (primary vs postsurgery vs post-trauma vs psoriatic), comorbidities, and smoking; (4) regarding age and body mass index, there is no minimum or maximum, but clinical judgment should be used at extremes of either; (5) the ideal dose of PRP is undetermined; and (6) the minimal volume required is unclear and may depend on the pathology. LEVEL OF EVIDENCE: Level V, expert opinion.

MRI of patellar stabilizers: Anatomic visibility, inter-reader reliability, and intra-reader reproducibility of primary and secondary ligament anatomy.

OBJECTIVE: To compare MRI features of medial and lateral patellar stabilizers in patients with and without patellar instability. METHODS: Retrospective study of 196 patients (mean age, 33.1 ± 18.5 years; 119 women) after diagnosis of patellar instability (cohort-1, acute patellar dislocation; cohort-2, chronic patellar maltracking) or no patellar instability (cohort-3, acute ACL rupture; cohort-4, chronic medial meniscus tear). On MRI, four medial and four lateral stabilizers were evaluated for visibility and injury by three readers independently. Inter- and intra-reader agreement was determined. RESULTS: Medial and lateral patellofemoral ligaments (MPFL and LPFL) were mostly or fully visualized in all cases (100%). Of the secondary patellar stabilizers, the medial patellotibial ligament was mostly or fully visualized in 166 cases (84.7%). Other secondary stabilizers were mostly or fully visualized in only a minority of cases (range, 0.5-32.1%). Injury scores for all four medial stabilizers were higher in patients with acute patellar dislocation than the other 3 cohorts (p < .05). Visibility inter- and intra-reader agreement was good for medial stabilizers (κ 0.61-0.78) and moderate-to-good for lateral stabilizers (κ 0.40-0.72). Injury inter- and intra-reader agreement was moderate-to-excellent for medial stabilizers (κ 0.43-0.90) and poor-to-moderate for lateral stabilizers (κ 0-0.50). CONCLUSION: The MPFL and LPFL were well visualized on MRI while the secondary stabilizers were less frequently visualized. The secondary stabilizers were more frequently visualized medially than laterally, and patellotibial ligaments were more frequently visualized compared to the other secondary stabilizers. Injury to the medial stabilizers was more common with acute patellar dislocation than with chronic patellar maltracking or other knee injuries.

Identifying patients with opioid use disorder using International Classification of Diseases (ICD) codes: Challenges and opportunities.

BACKGROUND AND AIMS: International Classification of Diseases (ICD) diagnosis codes are often used in research to identify patients with opioid use disorder (OUD), but their accuracy for this purpose is not fully evaluated. This study describes application of ICD-10 diagnosis codes for opioid use, dependence and abuse from an electronic health record (EHR) data extraction using data from the clinics' OUD patient registries and clinician/staff EHR entries. DESIGN: Cross-sectional observational study. SETTING: Four rural primary care clinics in Washington and Idaho, USA. PARTICIPANTS: 307 patients. MEASUREMENTS: This study used three data sources from each clinic: (1) a limited dataset extracted from the EHR, (2) a clinic-based registry of patients with OUD and (3) the clinician/staff interface of the EHR (e.g. progress notes, problem list). Data source one included records with six commonly applied ICD-10 codes for opioid use, dependence and abuse: F11.10 (opioid abuse, uncomplicated), F11.20 (opioid dependence, uncomplicated), F11.21 (opioid dependence, in remission), F11.23 (opioid dependence with withdrawal), F11.90 (opioid use, unspecified, uncomplicated) and F11.99 (opioid use, unspecified with unspecified opioid-induced disorder). Care coordinators used data sources two and three to categorize each patient identified in data source one: (1) confirmed OUD diagnosis, (2) may have OUD but no confirmed OUD diagnosis, (3) chronic pain with no evidence of OUD and (4) no evidence for OUD or chronic pain. FINDINGS: F11.10, F11.21 and F11.99 were applied most frequently to patients who had clinical diagnoses of OUD (64%, 89% and 79%, respectively). F11.20, F11.23 and F11.90 were applied to patients who had a diagnostic mix of OUD and chronic pain without OUD. The four clinics applied codes inconsistently. CONCLUSIONS: Lack of uniform application of ICD diagnosis codes make it challenging to use diagnosis code data from EHR to identify a research population of persons with opioid use disorder.

The NICHD Fetal 3D Study: A Pregnancy Cohort Study of Fetal Body Composition and Volumes.

There's a paucity of robust normal fractional limb and organ volume standards from a large and diverse ethnic population. The Fetal 3D Study was designed to develop research and clinical applications for fetal soft tissue and organ volume assessment. The NICHD Fetal Growth Studies (2009-2013) collected 2D and 3D fetal volumes. In the Fetal 3D Study (2015-2019), sonographers performed longitudinal 2D and 3D measurements for specific fetal anatomic structures in research ultrasounds of singletons and dichorionic twins. The primary aim was to establish standards for fetal body composition and organ volumes, overall and by maternal race/ethnicity, and determine if these standards vary for twins versus singletons. We describe study design, methods and details about reviewer training. Basic characteristics of this cohort, with their corresponding distributions of fetal 3D measurements by anatomic structure, are summarized. This investigation is responsive to critical data gaps in understanding serial changes in fetal subcutaneous fat, lean body mass and organ volume in association with pregnancy complications. In the future, this cohort can answer critical questions regarding the potential influence of maternal characteristics, lifestyle factors, nutrition, and biomarker and chemical data on longitudinal measures of fetal subcutaneous fat, lean body mass and organ volumes.

A modified Delphi consensus statement on patellar instability: part II.

Aims: The aim of this study was to establish consensus statements on medial patellofemoral ligament (MPFL) reconstruction, anteromedialization tibial tubercle osteotomy, trochleoplasty, and rehabilitation and return to sporting activity in patients with patellar instability, using the modified Delphi process. Methods: This was the second part of a study dealing with these aspects of management in these patients. As in part I, a total of 60 surgeons from 11 countries contributed to the development of consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered unanimous. Results: Of 41 questions and statements on patellar instability, none achieved unanimous consensus, 19 achieved strong consensus, 15 achieved consensus, and seven did not achieve consensus. Conclusion: Most statements reached some degree of consensus, without any achieving unanimous consensus. There was no consensus on the use of anchors in MPFL reconstruction, and the order of fixation of the graft (patella first versus femur first). There was also no consensus on the indications for trochleoplasty or its effect on the viability of the cartilage after elevation of the osteochondral flap. There was also no consensus on postoperative immobilization or weightbearing, or whether paediatric patients should avoid an early return to sport.

Editorial Commentary: Evaluation of Patellofemoral Instability Is Complex and Multifactorial.

The work-up of patellofemoral instability is complex and multifactorial. Patient factors (i.e., age, activity demand, goals/expectations), clinical presentation (pain, instability, or both), and physical examination (i.e., J-sign, apprehension into flexion), must be correlated with imaging findings (radiographs, magnetic resonance imaging, computed tomography) and anatomic risk factors, including patella alta, trochlear dysplasia, patellar tilt, lateralized force vector, valgus, femoral anteversion, and tibial torsion. Thus, developing a standard battery of reliable and reproducible radiographic measures of patellofemoral instability is a challenge. Imaging cut-offs provide insight into relative risk of recurrent instability. We still fall short in using imaging parameters to predict when to operate, what procedure(s) to perform, and how the patient might do. Future directions include the use of artificial intelligence and 3-dimensional measurements to help simplify a complex problem.

Association of Hip Dysplasia With Trochlear Dysplasia in Skeletally Mature Patients.

Background: Developmental dysplasia of the hip (DDH) and trochlear dysplasia (TD) are distinct pathologies with several important features in common. In addition to shared risk factors, both forms of dysplasia cause abnormal joint kinematics and force transmission, predisposing patients to pain, injuries to cartilage and soft tissue stabilizers, and ultimately arthritis. Purpose: To evaluate for an association between hip dysplasia and TD in skeletally mature patients with symptomatic hip dysplasia. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 48 patients with DDH who underwent periacetabular osteotomy were compared with 48 sex-matched patients who underwent hip arthroscopy for femoroacetabular impingement (FAI) between July 2014 and February 2021. All patients were skeletally mature. The Tönnis angle and lateral center-edge angle were measured on preoperative pelvis radiographs. Femoral version, trochlear depth, lateral trochlear inclination (LTI), tibial tubercle-trochlear groove distance (TTTG-d), and posterior lateral condylar angle (PLCA) were measured on preoperative magnetic resonance imaging scans of the symptomatic hip and ipsilateral knee. Continuous variables were compared between the patient groups using 2-sample t tests. Interobserver reliability was measured using the intraclass correlation coefficient. Results: Patients with DDH demonstrated a reduced trochlear depth compared with patients with FAI (3.6 vs 4.6 mm; P < .001). There were no differences between groups in femoral anteversion, LTI, TTTG-d, or PLCA. Two (4.2%) patients with FAI and 17 (35.4%) patients with DDH had a trochlear depth <3 mm (P < .001). One (2.1%) patient with FAI and 7 (14.6%) patients with DDH had an LTI <11° (P = .027). There was no difference between groups in frequency of a convex proximal trochlea, patient-reported ipsilateral knee pain, or ipsilateral knee procedures. Conclusion: Patients with DDH had reduced trochlear depth compared with patients with FAI, demonstrating a higher incidence of dysplastic trochlear features that may predispose patients to patellofemoral joint disease. Further research is needed to determine whether screening at-risk patients and treating TD will help to prevent symptomatic patellofemoral disease.

The Principles of Knee Joint Preservation: Operative Treatment Strategies.

➤ Joint alignment, meniscal status, and ligament stability are codependent factors involved in knee joint preservation, and any injury or imbalance can impact the knee articular cartilage status and can result in adverse clinical outcomes.➤ Cartilage preservation procedures in the knee will not result in optimal outcomes if there is joint malalignment, meniscal deficiency, or ligamentous instability.➤ Lower-extremity varus or valgus malalignment is a risk factor for the failure of an anterior cruciate ligament (ACL) reconstruction. It represents an indication for a high tibial osteotomy or distal femoral osteotomy in the setting of failed ACL reconstruction, and may even be considered in patients who have an initial ACL injury and severe malalignment.➤ An elevated posterior tibial slope increases the risk of failure of ACL reconstruction, whereas a decreased posterior tibial slope increases the risk of failure of posterior cruciate ligament reconstruction.

Discordant pathologic diagnoses of myelodysplastic neoplasms and their implications for registries and therapies.

Myelodysplastic neoplasms (MDS) are a collection of hematopoietic disorders with widely variable prognoses and treatment options. Accurate pathologic diagnoses present challenges because of interobserver variability in interpreting morphology and quantifying dysplasia. We compared local clinical site diagnoses with central, adjudicated review from 918 participants enrolled in the ongoing National Heart, Lung, and Blood Institute National MDS Natural History Study, a prospective observational cohort study of participants with suspected MDS or MDS/myeloproliferative neoplasms (MPNs). Locally, 264 (29%) were diagnosed as having MDS, 15 (2%) MDS/MPN overlap, 62 (7%) idiopathic cytopenia of undetermined significance (ICUS), 0 (0%) acute myeloid leukemia (AML) with <30% blasts, and 577 (63%) as other. Approximately one-third of cases were reclassified after central review, with 266 (29%) diagnosed as MDS, 45 (5%) MDS/MPN overlap, 49 (5%) ICUS, 15 (2%) AML with <30%, and 543 (59%) as other. Site miscoding errors accounted for more than half (53%) of the local misdiagnoses, leaving a true misdiagnosis rate of 15% overall, 21% for MDS. Therapies were reported in 37% of patients, including 43% of patients with MDS, 49% of patients with MDS/MPN, and 86% of patients with AML with <30% blasts. Treatment rates were lower (25%) in cases with true discordance in diagnosis compared with those for whom local and central diagnoses agreed (40%), and receipt of inappropriate therapy occurred in 7% of misdiagnosed cases. Discordant diagnoses were frequent, which has implications for the accuracy of study-related and national registries and can lead to inappropriate therapy. This trial was registered at www.clinicaltrials.gov as #NCT05074550.

Maternal asthma in relation to infant size and body composition.

Background: Asthma affects 10% of pregnancies and may influence offspring health, including infant size and body composition, through hypoxic and inflammatory pathways. Objective: We sought to determine associations between maternal asthma and asthma phenotypes during pregnancy and infant size and body composition. Methods: The B-WELL-Mom study (2015-19) is a prospective cohort of 418 pregnant persons with and without asthma recruited in the first trimester of pregnancy from 2 US obstetric clinics. Exposures were maternal self-reported active asthma (n = 311) or no asthma (n = 107), and asthma phenotypes were classified on the bases of atopy, onset, exercise induced, control, severity, symptomology, and exacerbations. Outcomes were infant weight, length, head circumference, and skinfold measurements at birth and postnatal follow-up, as well as fat and lean mass assessed by air displacement plethysmography at birth. Adjusted multivariable linear regression examined associations of maternal asthma and asthma phenotypes with infant outcomes. Results: Offspring were born at a mean ± SD of 38 ± 2.3 weeks' gestation and were 18 ± 2.2 weeks of age at postnatal follow-up. Infants of participants with asthma had a mean ± SD fat mass of 11.0 ± 4.2%, birth weight of 3045.8 ± 604.3 g, and postnatal follow-up weight of 6696.4 ± 964.2 g, which were not different from infants of participants without asthma (respectively, ß [95% confidence interval]: -0.1 [-1.4, 1.3], -26.7 [-156.9, 103.4], and 107.5 [-117.3, 332.3]). Few associations were observed between asthma or asthma phenotypes and infant size or body composition. Conclusions: In a current obstetric cohort, maternal asthma during pregnancy was not associated with differential infant size or body composition.

Bifocal avulsion fracture and fixation of the patellar tendon: a case report.

Acute distal patella tendon avulsion from the tibial tubercle (TT) is a relatively rare injury that is usually described in the adolescents or elderly population in their 7th or 8th decades. Bifocal avulsion fractures of the patella tendon from the TT and the distal pole of the patella are exceptionally rare in adults. In this case report, we present a 52-year-old healthy old male who was treated for bifocal avulsion of the patellar tendon with open reduction and internal fixation augmented with two ULTRATAPE sutures. To our knowledge, this is the first case report to describe this injury in a healthy middle-aged patient.

Biomechanical Forces of the Lateral Knee Joint Following Meniscectomy and Meniscus Transplantation in Pediatric Cadavers.

INTRODUCTION: Lateral meniscus transplantation successfully treats symptomatic meniscus deficiency in children. Although clinical outcomes are well-characterized, joint forces in meniscus-deficient and transplant states are unknown. The purpose of this study was to characterize contact area (CA) and contact pressures (CP) of transplanted lateral meniscus in pediatric cadavers. We hypothesize that (1) compared with the intact state, meniscectomy will decrease femorotibial CA and increase CP, and increase contact pressure (CP) and (2) compared with the meniscectomy state, meniscus transplantation will improve contact biomechanics toward the intact meniscus state. METHODS: Pressure-mapping sensors were inserted underneath the lateral meniscus of eight cadaver knees aged 8 to 12 years. CA and CP on the lateral tibial plateau were measured in the intact, meniscectomy, and transplant states each at 0°, 30°, and 60° of knee flexion. Meniscus transplant was anchored with transosseous pull-out sutures and sutured to the joint capsule with vertical mattresses. The effects of meniscus states and flexion angle on CA and CP were measured by a two-way analysis of variance repeated measures model. One-way analysis of variance measured pairwise comparisons between meniscus states. RESULTS: Regarding CA, at 0°, no differences between the groups reached significance. Meniscectomy reduced CA at 30° ( P = 0.043) and 60° ( P = 0.001). Transplant and intact states were comparable at 30°. At 60°, transplant significantly increased CA ( P = 0.04). Regarding contact pressure, the average pressure increased with meniscectomy at all angles of flexion (0° P = 0.025; 30° P = 0.021; 60° P = 0.016) and decreased with transplant relative to respective intact values. Peak pressure increased with meniscectomy at 30° ( P = 0.009) and 60° ( P = 0.041), but only reached intact comparable values at 60°. Pairwise comparisons support restoration of average CP with transplant, but not peak CP. DISCUSSION: Pediatric meniscus transplantation improves average CP and CA more than peak CP, but does not completely restore baseline biomechanics. Net improvements in contact biomechanics after transplant, relative to the meniscectomy state, support meniscus transplant. STUDY DESIGN: Descriptive laboratory study, Level III.

Knee MRI: Meniscus Roots, Ramps, Repairs, and Repercussions.

Menisci play an essential role in maintaining normal pain-free function of the knee. While there are decades of MRI literature on the tears involving the meniscus body and horns, there is now a surge in knowledge regarding injuries at the meniscus roots and periphery. The authors briefly highlight new insights into meniscus anatomy and then summarize recent developments in the understanding of meniscus injuries that matter, emphasizing meniscus injuries at the root and peripheral (eg, ramp) regions that may be missed easily at MRI and arthroscopy. Root and ramp tears are important to diagnose because they may be amenable to repair. However, if these tears are left untreated, ongoing pain and accelerated cartilage degeneration may ensue. The posterior roots of the medial and lateral menisci are most commonly affected by injury, and each of these injuries is associated with distinctive clinical profiles, MRI findings, and tear patterns. Specific diagnostic pitfalls can make the roots challenging to evaluate, including MRI artifacts and anatomic variations. As with root tears, MRI interpretation and orthopedic treatment have important differences for injuries at the medial versus lateral meniscus (LM) periphery (located at or near the meniscocapsular junction). Medially, ramp lesions typically occur in the setting of an anterior cruciate ligament rupture and are generally classified into five patterns. Laterally, the meniscocapsular junction may be injured in association with tibial plateau fractures, but disruption of the popliteomeniscal fascicles may also result in a hypermobile LM. Updated knowledge of the meniscus root and ramp tears is crucial in optimizing diagnostic imaging before repair and understanding the clinical repercussions. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available in the Online Learning Center.