Knee Pain Research Articles

Open wedge high tibial osteotomy alters patellofemoral joint kinematics: A multibody simulation study.

Changes in lower limb alignment after open-wedge high tibial osteotomy (owHTO) influence joint kinematics. The aim of this study was to investigate the morphological and kinematic changes of the knee joint, in particular the patellofemoral joint, using a multibody simulation model. OwHTO with an open tibial wedge of 6-12 mm (1 mm intervals) was virtually performed on each of 13 three-dimensional (3D) computer-aideddesign models (CAD models) derived from computer tomography scans of full-leg cadaver specimens. For each owHTO, an individual biomechanical simulation model was built and knee flexion from 5° to 100° was simulated using a multibody simulation model of the native knee. Morphologic and alignment parameters as well as tibiofemoral and patellofemoral kinematic parameters were evaluated. Almost linear changes in tibial tuberosity trochlea groove(TT-TG) (0.42 mm/1 mm wedge height) were observed which led to pathological values (TT-TG > 20 mm) in 3 out of 13 knees. Furthermore, a 6 mm increase in osteotomy wedge height increased lateral patellofemoral rotation by 0.8° (range: 0.39° to 1.11°) and led to a lateral patellar translation of 0.8 mm (range: 0.37-3.11 mm) on average. Additionally, valgisation led to a medial translation of the tibia and a decrease in the degree of tibial internal rotation during knee flexion of approximately 0.3°/1 mm increase in osteotomy wedge height. The increase in TT-TG and the biomechanical effects observed influence patellofemoral tracking, which may increase retropatellar pressure and are potential risk factors for the development of anterior knee pain.

Prosthetic joint infection caused by Mediterraneibacter gnavus following total knee arthroplasty, challenges in anaerobic bacteria identification

BackgroundMediterraneibacter gnavus is a Gram positive, non-sporulated, obligate anaerobe diplococci. It was first described in 1974 by Moore et al. (under the name Ruminococcus gnavus) from faeces and contents of the gastrointestinal tract of humans. It is a relatively common member of the human gut microbiota, nevertheless its role as a pathogenic bacterium has not been completely elucidated yet and it seems to depend on numerous factors, including those of the host. Here we present a case of prosthetic joint infection following total knee arthroplasty by M. gnavus.Case presentationA 74 years old patient was admitted to the emergency department presenting with acute onset of left knee pain and swelling 20 days after total left knee arthroplasty. Follow-up revealed erythema and oedema without signs of fluctuation or purulent discharge from the surgical wound and elevated inflammatory reactants. Synovial fluid was taken for bacterial culture and antibiotic treatment with ceftazidime and daptomycin was established. Examination of the synovial fluid revealed abundant polymorphonuclear leucocytes, without visualizing bacteria. After four days of incubation, anaerobic culture exhibit growth of small, grey, umbilicated colonies in pure culture on Schaedler agar. The microorganism was identified as R. gnavus by MALDI-TOF (Bruker Daltonics) and M. gnavus by 16S ribosomal bacterial sequencing. The isolated showed susceptibility to the most commonly used anaerobicidal antibiotics except for clindamycin. Surgical treatment and infection source control included DAIR (debridement, antibiotics, and implant retention) and vacuum assisted therapy. The patient was discharged after six weeks with a 3-month course of oral amoxicillin as consolidation therapy. Subsequent follow-up revealed adequate wound healing with no signs of infection.ConclusionsMediterraneibacter gnavus have been reported as the causal microorganism in a range of human infections, nevertheless its identification remains challenging. Infection of prosthetic joints by anaerobic microorganisms is uncommon and is not considered in its empirical antibiotic treatment, thus, correct and swift identification of anaerobic bacteria in these cases is paramount.

Relationship between patellar resurfacing and postoperative anterior knee pain in total knee arthroplasty

Aims: To retrospectively demonstrate the effect of patellar resurfacing (PR) on the clinical and functional outcomes of total knee arthroplasty (TKA). Methods: The files of 257 patients who presented to our clinic between 2013 and 2022 and underwent TKA due to the diagnosis of grade IV gonarthrosis were screened retrospectively. Thirty-two patients were excluded due to not attending regular follow-up, receiving steroid treatment, or being morbidly obese. The sample consisted of 225 patients, of whom 123 underwent PR (Group A) and 102 did not undergo PR (Group B). The Sperner classification was used to evaluate the level of patellar arthrosis. The effect of PR on postoperative clinical and functional outcomes in patients undergoing TKA was investigated using the WOMAC knee functional scoring and Visual Analog Scale (VAS) for clinical and functional evaluation at six, 12, and 24 months postoperatively. Results: The presence of anterior knee pain wasstatistically significantly lower in Group A than in Group B (p=0.0001). There was no statistically significant difference between the comorbidity distributions of the groups. The preoperative-to-postoperative changes in the mean VAS and WOMAC scores were statistically significantly higher in Group A compared to Group B (p=0.0001 for both). Conclusion: The implementation of PR in TKA may vary depending on countries, clinics, and even surgeons. In the current study, PR was found to contribute positively to the clinical and functional outcomes of patients by preventing complications such as anterior knee pain that may develop due to patellar arthrosis in the postoperative period.

Psychosocial Interventions to Reduce Post operative Pain in Total Knee Arthroplasty: A Systematic Review

Background: Total knee arthroplasty (TKA) is a common surgical remedy for patients with end-stage osteoarthritis. Although TKA is generally effective, a significant number of patients experience chronic post-surgical pain. Psychosocial interventions have increasingly become an area of interest in pain management following surgical procedures. Purpose: We aimed to evaluate the impact of pre-operative, peri-operative, and post-operative psychosocial interventions on reducing the likelihood of developing chronic pain after TKA. Methods: We performed a systematic review following the Cochrane guidelines and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. A comprehensive search strategy was employed using PubMed, Embase, and Cochrane Central Register of Controlled Trials. Inclusion criteria were (1) patients undergoing; (2) pain outcome assessed ≥1 month post-operatively; (3) prospective and longitudinal study design (eg, randomized controlled trial, experimental non-randomized trial, cohort, case-control studies with measurement of exposure prior to outcome); (4) English language; and (5) psychosocial intervention (cognitive-behavioral, biopsychosocial, dialectical behavioral, psychoeducation, mindfulness, meditation, psychotherapy, relaxation, mind-body therapies, hypnosis). Exclusion criteria were non-primary literature (eg, review articles), non–peer-reviewed studies, and conference proceedings. The methodological quality of included studies was assessed using Cochrane’s tool for Risk of Bias 2 (RoB 2), the methodological index for non-randomized studies (MINORS), and the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I). Results: Of 4297 studies reviewed with title and abstract, 4160 were excluded. Of the remaining 137 studies that underwent full-text review, 122 were excluded using the same inclusion and exclusion criteria, and 15 studies were included. Our review indicates a variable but positive impact of psychosocial interventions, such as pre-operative education, relaxation techniques, and cognitive-behavioral therapy, on post-TKA pain. Of the 15 included studies, 9 studies found that psychosocial interventions reduced post-TKA pain. Our review also suggests that cognitive-behavioral therapy may aid in reducing kinesiophobia, pain catastrophizing, and knee pain intensity. For the 12 randomized studies, the risk of bias was deemed “high” concerns for 3 studies, “some” concerns for 5 studies, and “low” concerns for 4 studies. For the 3 non-randomized studies, the risk of bias was deemed “moderate” due to confounding bias. Conclusions: This systematic review of level-I and level-II studies found that the integration of psychosocial interventions into care protocols for TKA offers benefits including improved patient satisfaction and quality of life and reduced health care costs. Limitations include heterogeneity in intervention types and outcomes measured and the varying levels of risk of bias across studies, which may affect the generalizability of the findings. The findings support a broader adoption of holistic, patient-centered approaches in pain management after TKA, emphasizing the importance of psychological well-being for optimal patient outcomes. However, the evidence is limited and constitutes a strong impetus for the further study of these interventions.

The influence of pain catastrophizing on pain and function after knee arthroplasty in knee osteoarthritis

Pain catastrophizing is an exaggerated focus on pain sensations. It may be an independent factor influencing pain and functional outcomes of knee arthroplasty. We aimed to evaluate the association between pre-operative pain catastrophizing with pain and function outcomes up to one year after knee arthroplasty. We used data from a cohort study of patients undergoing primary knee arthroplasty (either total or unicompartmental arthroplasty) for knee osteoarthritis. Pain catastrophizing was assessed pre-operatively using the Pain Catastrophizing scale (PCS). Other baseline variables included demographics, body mass index, radiographic severity, anxiety, depression, and knee pain and function assessed using the Western Ontario and McMaster University Index (WOMAC). Patients completed the WOMAC at 6- and 12-months after arthroplasty. WOMAC pain and function scores were converted to interval scale and the association of PCS and changes of WOMAC pain and function were evaluated in generalized linear regression models with adjustment with confounding variables. Of the 1136 patients who underwent arthroplasty (70% female, 84% Chinese, 92% total knee arthroplasty), 1102 and 1089 provided data at 6- and 12-months post-operatively. Mean (± SD) age of patients was 65.9 (± 7.0) years. PCS was associated with a change in WOMAC pain at both 6-months and 12-months (β = − 0.04, 95% confidence interval: − 0.06, − 0.02; P < 0.001) post-operatively after adjustment in multivariable models; as well as change in WOMAC function at 6-months and 12-months. In this large cohort study, pre-operative pain catastrophizing was associated with lower improvements in pain and function at 6-months and 12-months after arthroplasty.

Association of physical activity trajectories over 8 years and risk of knee replacement: data from the osteoarthritis initiative

BackgroundTo identify physical activity (PA) trajectories in adults with or at risk of knee osteoarthritis and to evaluate the association of PA trajectories with incident knee replacement (KR).MethodsThis study used data from the Osteoarthritis Initiative. The Physical Activity Scale for the Elderly and the KR were assessed annually from baseline to 9 years. Individuals were included if they did not undergo KR surgery at baseline and had data on PA at ≥ 1 visit before KR. Latent class growth mixture Modeling was used to identify the optimal trajectories of PA before KR. Log-binomial regression models were used to assess the association between PA trajectories and the risk of KR. Data analyses were conducted in all individuals and those with radiographic osteoarthritis (ROA) and significant knee pain (Western Ontario and McMaster Osteoarthritis Index pain score of ≥ 5 on a 0–20 scale) at baseline, respectively.ResultsOf 4731 participants (mean age 61.1 years, 58.5% female), four distinct and slightly declined PA trajectories were identified. Compared to individuals with a “Low” PA trajectory, those with “Medium-low”, “Medium-high”, or “High” PA trajectories were not significantly associated with the risk of KR (risk ratios: 0.97–1.19, all p > 0.05). Similar PA trajectories and associations with the risk of KR were observed in the subgroups of individuals with radiographic osteoarthritis and those with significant knee pain at baseline, respectively.ConclusionIn participants with or at risk of knee osteoarthritis, PA slightly declines over time and may play no role in the risk of KR.

Closed-Loop Infraslow Brain-Computer Interface can Modulate Cortical Activity and Connectivity in Individuals With Chronic Painful Knee Osteoarthritis: A Secondary Analysis of a Randomized Placebo-Controlled Clinical Trial.

Introduction. Chronic pain is a percept due to an imbalance in the activity between sensory-discriminative, motivational-affective, and descending pain-inhibitory brain regions. Evidence suggests that electroencephalography (EEG) infraslow fluctuation neurofeedback (ISF-NF) training can improve clinical outcomes. It is unknown whether such training can induce EEG activity and functional connectivity (FC) changes. A secondary data analysis of a feasibility clinical trial was conducted to determine whether EEG ISF-NF training can significantly alter EEG activity and FC between the targeted cortical regions in people with chronic painful knee osteoarthritis (OA). Methods. A parallel, two-arm, double-blind, randomized, sham-controlled clinical trial was conducted. People with chronic knee pain associated with OA were randomized to receive sham NF training or source-localized ratio ISF-NF training protocol to down-train ISF bands at the somatosensory (SSC), dorsal anterior cingulate (dACC), and uptrain pregenual anterior cingulate cortices (pgACC). Resting state EEG was recorded at baseline and immediate post-training. Results. The source localization mapping demonstrated a reduction (P = .04) in the ISF band activity at the left dorsolateral prefrontal cortex (LdlPFC) in the active NF group. Region of interest analysis yielded significant differences for ISF (P = .008), slow (P = .007), beta (P = .043), and gamma (P = .012) band activities at LdlPFC, dACC, and bilateral SSC. The FC between pgACC and left SSC in the delta band was negatively correlated with pain bothersomeness in the ISF-NF group. Conclusion. The EEG ISF-NF training can modulate EEG activity and connectivity in individuals with chronic painful knee osteoarthritis, and the observed EEG changes correlate with clinical pain measures.

Neuritis ossificans mimicking a malignancy in a child: case report and literature review.

We present the case of a child with neuritis ossificans after acute trauma, treated conservatively. The aim of the review is to compare several parameters in this disease. Emphasis is placed on the clinical-radiological features distinguishing neuritis ossificans from malignancy to avoid unnecessary biopsy and surgery.A literature review was performed. Only 18 cases were described. Except for one, all describe adults, and none had acute trauma. Nearly all were treated surgically.Our 13-year-old patient presented with posterior knee pain after trauma. MRI demonstrated a mass within the tibial nerve with oedema, some lymph nodes and increased avidity on 18fluoro-2-deoxyglucose-positron emission tomography. These findings can be reactive but also associated with malignancy. However, eggshell-like calcifications in the periphery of the mass were seen on CT. Biopsy and resection were proposed. Follow-up visits over the next weeks showed remarkable clinical improvement. Wait-and-scan was advised after international discussion. Follow-up imaging after 2months showed resolution of the oedema and volume reduction of the mass, suggesting a benign pathology. Diagnosis of neuritis ossificans was proposed based on the clinical and radiological features. There was a favorable course with no complaints after twomonths. Imaging after sevenmonths showed an almost complete regression.Neuritis ossificans should be considered within a painfull (mono)neuropathy. The initial inflammatory phase may mimic malignancy, misleading clinicians toward biopsy or surgery with the risk of nerve damage. As seen in our case, neuritis ossificans can be a self-limiting process. Therefore, conservative therapy should be considered with a wait-and-scan approach.

Synovial hemangioma presenting with chronic painful infrapatellar mass: a case report

BackgroundSynovial hemangiomas are rare benign vascular anomalies surrounded by a synovial lining and were first described by Bouchut in 1856. These neoplasms can develop in the intra-articular region, resulting in effusions and knee pain. However, their cause remains unknown. Prompt diagnosis and intervention are critical to prevent chondral damage. Histopathological examination is used to achieve the diagnosis, which is often delayed because of a lack of specific clinical signs. This report describes a unique case in which a painful infrapatellar mass was diagnosed as a synovial hemangioma. The absence of typical magnetic resonance imaging (MRI) findings highlights the importance of arthroscopic excision for diagnosis and symptom relief.Case presentationA 20-year-old woman presented with persistent anterior left knee pain that became exacerbated when she climbed stairs. Despite previous pain management and physical therapy, she developed a painful lump beneath her patella that worsened over time. She had also undergone arthrocentesis, but this did not relieve her pain. Physical examination revealed a palpable, immobile 5-cm mass along the patellar tendon with limited knee flexion and extension and normal ligament stability. T1-weighted fat-saturated MRI of the left knee with gadolinium-based contrast revealed a lobulated intra-articular mass in Hoffa’s fat pad that resembled a soft tissue chondroma. A biopsy of the mass was performed to provide histopathological evidence, confirming the benign nature of the mass. The subsequent excisional arthroscopy, combined with incision enlargement for mass removal, confirmed the histopathologic diagnosis of synovial hemangioma based on the presence of numerous dilated blood vessels and venous proliferation within sections of the synovium. Recovery was complete, and no residual tumor was detected on follow-up MRI after 1 year.ConclusionThis case study emphasizes the importance of arthroscopic excision over open surgery for patients with synovial hemangioma. The minimally invasive nature of arthroscopy combined with the well-encapsulated nature and location of the mass facilitates complete resection.

Improving biological and mechanical properties of bioprinted PCL-alginate-chondrocyte scaffolds for patellofemoral cartilage tissue regeneration

In this study, polycaprolactone (PCL) scaffolds have been employed as structural framework scaffolds for patellofemoral cartilage tissue regeneration. The biomechanical and biological properties of different scaffolds were investigated by varying alginate concentrations and the number of scaffold layers. Patellofemoral cartilage defects result in knee pain and reduced mobility, and they are usually treated with conventional methods, often with limited success. Generally, tissue-engineered PCL-alginate scaffolds fabricated by bioprinting technology show promise for enhanced cartilage regeneration due to the biocompatibility and mechanical stability of PCL. In addition, alginate is known for its cell encapsulation capabilities and for promoting cell viability. Biological and morphological assessments, utilizing water contact angle, cell adhesion tests, MTT assays, and scanning electron microscopy (SEM), informed the selection of the optimized scaffold. Comparative analyses between the initial optimal scaffolds with the same chemical composition also included flexural and compression tests and fracture surface observations using SEM. The controlled integration of PCL and alginate offers a hybrid approach, that assembles the mechanical strength of PCL and the bioactive properties of alginate for tissue reconstruction potential. This study aims to identify the most effective scaffold composition for patellofemoral articular cartilage tissue engineering, emphasizing cell viability, structural morphology, and mechanical integrity. The results showed that the optimum biomechanical and biological properties of scaffolds were obtained with a 10% alginate concentration in the monolayer of PCL structure. The findings contribute to regenerative medicine by advancing the understanding of functional tissue constructs, bringing us closer to addressing articular cartilage defects and related clinical challenges.

Item generation for a new patient-reported outcome measure: The non-traumatic anterior knee pain (AKP)-YOUTH scale

BackgroundNon-traumatic anterior knee pain affects one in every five adolescents. Despite the commonality of the condition, there are no patient-reported outcome measures developed specifically for this population. The aim of this study was to identify domains and develop a preliminary item bank for adolescents with non-traumatic anterior knee pain. ParticipantsTwenty-one adolescents with anterior knee pain participated in semi-structured interviews which explored their experience of living with knee pain. Following thematic analysis, we generated an item bank based on the domains which emerged from the impact their knee pain had on their daily life. Ten clinical experts provided input on the preliminary item bank via an online survey. Cognitive interviews were conducted using the think-aloud approach with ten adolescents to evaluate the comprehensibility and face validity of the items. ResultsFrom the interviews we identified four overarching domains where adolescents were impacted by their knee pain: knee symptoms, limitations in physical activity/sport, limitations in social activities, and emotional impact of pain. Eighteen items were initially developed and expanded to 23 following clinical expert input. The cognitive interviews with adolescents demonstrated that the items were comprehensive, understandable, and relevant for adolescents. ConclusionThis study developed an item bank of 23 items. These spanned four domains of impact for adolescents with anterior knee pain. The items had good face validity and were deemed relevant and understandable for adolescents with knee pain. Further steps are needed to validate and reduce the items for the non-traumatic anterior knee pain (AKP)-YOUTH scale.

A novel methodology utilizing microchip implants to monitor individual activity and body temperature for assessing knee pain in group-housed rats

The pain assessment in animals is challenging as they cannot verbally express the site and severity of pain. In this study, we tried a small implantable actimeter, “Nanotag”, to monitor spontaneous locomotor activity and body temperature in animals suffering from a chemical-induced rat knee arthritis as compared to naïve and steroid-treated rats. Nanotag could detect the decrease in locomotor activity quickly after the arthritis induction and anti-inflammation analgesic treatment by intra-articular injection of steroid significantly improved locomotor activity. These changes were in the same line with those of a conventional knee pain evaluation method (incapacitance test). Nanotag can be utilized as the non-interventional, continuous, and completely objective monitoring the amount of pain in rat knee arthritis model. This traditional yet innovative method may be universally applicable to various pain models and species, making it a worthwhile device for research across diverse fields.

Increased nerve growth factor expression and osteoclast density are associated with subchondral bone marrow lesions in osteoarthritic knees

ObjectivesSubchondral bone marrow lesions (BMLs) detected on magnetic resonance imaging in knee osteoarthritis (OA) are associated with knee pain, though the mechanisms remain unknown. Increased nerve growth factor (NGF) expression and osteoclast density in subchondral bone appear to be the key features associated with bone pain in knee OA. Therefore, we aimed to identify associations among NGF, osteoclasts, and BMLs in knee OA. MethodsTwenty tibial plateaus were obtained from patients undergoing total knee arthroplasty for medial knee OA with BMLs at the medial tibial plateau (MTP). Osteochondral tissue samples from the weight-bearing part of the MTP, with and without BML, and from the weight-bearing part of the lateral tibial plateau (LTP), without BML, were collected. NGF expression and density of osteoclasts were compared among the three osteochondral tissue types. ResultsMTP bone with BMLs exhibited significantly higher NGF expression in bone marrow space and osteochondral channel, and higher osteoclast density than MTP bone without BML and LTP bone. The mean differences in NGF-positive area in the bone marrow space and the percentage of NGF-positive channels between MTP bones with and without BML were 9.0% (95% confidence interval [CI]: 5.9–12.1%) and 23.1% (95% CI: 11.3–35.0%), respectively. The difference in osteoclast density between MTP bones with and without BML was 0.6 osteoclasts per mm (95% CI: 0.3–0.9 osteoclasts per mm). ConclusionsIncreased NGF expression and osteoclast density are associated with subchondral BMLs in knee OA, contribute to understanding the mechanisms underlying BML-related bone pain in knee OA.

Reliable prediction of implant size and axial alignment in AI-based 3D preoperative planning for total knee arthroplasty

The size and axial alignment of prostheses, when planned during total knee replacement (TKA) are critical for recovery of knee function and improvement of knee pain symptoms. This research aims to study the effect of artificial intelligence (AI)-based preoperative three dimensional (3D) planning technology on prosthesis size and axial alignment planning in TKA, and to compare its advantages with two dimensional (2D) X-ray template measurement technology. A total of 60 patients with knee osteoarthritis (KOA) who underwent TKA for the first time were included in the AI (n = 30) and 2D (n = 30) groups. The preoperative and postoperative prosthesis size, femoral valgus correction angle (VCA) and hip-knee-ankle angle (HKA) were recorded and compared between the two groups. The results of the University of Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and the American Knee Association Score (AKS) were evaluated before surgery, 3 months, 6 months, and 12 months after surgery. The accuracy of prosthesis size, VCA and HKA prediction in AI group was significantly higher than that in 2D group (P < 0.05). The WOMAC and AKS scores in AI group at 3 months, 6 months and 12 months after surgery were better than those in 2D group (P < 0.05). Both groups showed significant improvement in WOMAC and AKS scores at 12 months follow-up. AI-based preoperative 3D planning technique has more reliable planning effect for prosthesis size and axial alignment in TKA.

The painful knee in children

Knee pain is one of the most common reasons for medical consultation for musculoskeletal problems in the paediatric population. The aetiology is of very variable origin and necessitates aprecise assessment. In addition to athorough anamnesis, clinical and imaging examination methods, as well as laboratory diagnostics are of utmost importance to establish aproper diagnosis and an adequate treatment regimen. This chapter summarises the current diagnostic algorithm for dealing with knee pain in children and adolescents.

Prevalence of Musculoskeletal Disorders in Railway Employees: A Survey Study

Background: Work-related musculoskeletal disorders (WMSD) related with repetitive and demanding working conditions continue to represent one of the biggest problems in industrialized countries. The railway employees have high possibility of showing musculoskeletal pain due to repetitive motions, lifting heavy loads, awkward posture which leads to bending and twisting injuries and static posture for long duration during. Aim and Objective: To determine the prevalence and risk factors of musculoskeletal disorders in railway employees. Methodology: The study was conducted among 100 railway employees. The data was collected using self-administered Questionnaire, Nordic Musculoskeletal Questionnaire and Perceived Stress Scale. Both male and female employees having at least 1 year of experience were includes. Result and Conclusion: the 12-month prevalence of musculoskeletal disorders among railway employees was 79%. Low back pain (26.6%) was found to be most prevalent followed by neck pain (22.8%) and knee pain (20.3%). The Gangmans/trackmans and Sahayaks were identified to have maximum impact which led to WMSDs. The occurrence of MSD was associated with factors such as age, nature of work, working hours, lifting, and lowering heavy loads, working at pace set by machine and prolonged standing. Thus, education about ergonomics and body posture awareness would be instrumented in prevention of MSDs, thus are recommended. Keywords: Prevalence, Musculoskeletal Disorders, Risk Factors, Railway Employees.

Does Patellar Height Influence Range of Motion and Anterior Knee Pain after Distal Femur Endoprosthesis Reconstruction?

Objectives: This study aims to evaluate the patellar height changes after distal femur (DF) endoprosthetic replacement (EPR) and its impact on anterior knee pain (AKP) and range of motion (ROM). Methods: A retrospective review of three institutions' databases was performed. The patellar height was determined using the modified Insall-Salvati ratio (MIS), the Blackburne-Peel (BP) and the Caton-Deschamps (CD) indexes. Data regarding AKP and ROM were collected. Results: A total of 199 patients were included. The mean age at presentation was 37.9 ± 23.1 years. The mean one-year follow-up MIS, BP and CD were 1.52 (sd: 0.41), 0.82 (sd: 0.33) and 0.93 (sd: 0.33). Patellar height decreased significantly compared to the pre-operative values according to all three scores (p < 0.001). AKP was reported by 34 (17.1%) patients at 1 year follow-up. Patients with patella baja (MIS < 1.2) or pseudo patella baja (CD < 0.6) had a higher incidence of AKP (p = 0.037 and p = 0.024, respectively). The mean flexion ROM was 91°, with a direct correlation with patellar height (MIS p = 0.020, BP p = 0.036 and CD p = 0.036). Conclusion: The restoration of the native position of the joint line in DF EPR is important to maintain optimal patellofemoral biomechanics. Despite surgeons' tendency toward a reduction in patellar height with respect to pre-operative values, an increase in patellar height might help to achieve better knee flexion and reduce AKP.

Disease-modifying rdHSV-CA8* non-opioid analgesic gene therapy treats chronic osteoarthritis pain by activating Kv7 voltage-gated potassium channels.

Chronic pain is common in our population, and most of these patients are inadequately treated, making the development of safer analgesics a high priority. Knee osteoarthritis (OA) is a primary cause of chronic pain and disability worldwide, and lower extremity OA is a major contributor to loss of quality-adjusted life-years. In this study we tested the hypothesis that a novel JDNI8 replication-defective herpes simplex-1 viral vector (rdHSV) incorporating a modified carbonic anhydrase-8 transgene (CA8*) produces analgesia and treats monoiodoacetate-induced (MIA) chronic knee pain due to OA. We observed transduction of lumbar DRG sensory neurons with these viral constructs (vHCA8*) (~40% of advillin-positive cells and ~ 50% of TrkA-positive cells colocalized with V5-positive cells) using the intra-articular (IA) knee joint (KJ) route of administration. vHCA8* inhibited chronic mechanical OA knee pain induced by MIA was dose- and time-dependent. Mechanical thresholds returned to Baseline by D17 after IA KJ vHCA8* treatment, and exceeded Baseline (analgesia) through D65, whereas negative controls failed to reach Baseline responses. Weight-bearing and automated voluntary wheel running were improved by vHCA8*, but not negative controls. Kv7 voltage-gated potassium channel-specific inhibitor XE-991 reversed vHCA8*-induced analgesia. Using IHC, IA KJ of vHCA8* activated DRG Kv7 channels via dephosphorylation, but negative controls failed to impact Kv7 channels. XE-991 stimulated Kv7.2-7.5 and Kv7.3 phosphorylation using western blotting of differentiated SH-SY5Y cells, which was inhibited by vHCA8* but not by negative controls. The observed prolonged dose-dependent therapeutic effects of IA KJ administration of vHCA8* on MIA-induced chronic KJ pain due to OA is consistent with the specific activation of Kv7 channels in small DRG sensory neurons. Together, these data demonstrate for the first-time local IA KJ administration of vHCA8* produces opioid-independent analgesia in this MIA-induced OA chronic pain model, supporting further therapeutic development.

Decision-making in unicompartmental knee arthroplasty using radiological parameters in South Asian populations

Background: Many patients who visit orthopedic surgeons mainly complained of knee pain, which is often diagnosed as osteoarthritis affecting the medial compartment, whereas the lateral compartment and patello-femoral joint remain relatively unaffected. AIM: This study aimed to establish criteria for patient selection and validate an evidence-based approach for selecting candidates for unicompartmental knee arthroplasty (UKA). Key considerations in patient selection for UKA include identifying the presence of bone-on-bone osteoarthritis in the medial compartment, ensuring a functionally normal anterior cruciate ligament, maintaining full-thickness cartilage in the lateral compartment, verifying a functionally normal medial collateral ligament, and confirming the absence of severe damage lateral to the patello-femoral joint. MATERIALS AND METHODS: From a consecutive cohort of 390 patients with medial knee pain, preoperative radiographs of bilateral knee including anteroposterior/lateral/Rosenberg/20° valgus stress views were collected, and results were tabulated. Patients were categorized into appropriate groups. The suitability for UKA was determined based on the Oxford radiological decision aid, history, examination, and radiographic assessment including stress radiographs. RESULTS: The Oxford radiological decision aid demonstrated 92% sensitivity and 88% specificity. According to the radiographic assessment, 49% of the knees were considered suitable for Oxford UKA (OUKA), whereas 51% were deemed unsuitable. Among the 51 knees identified as unsuitable for OUKA, 40% did not meet one radiographic criterion, 38% did not meet two criteria, 22% did not meet three criteria, and 1% did not meet four criteria. CONCLUSION: The Oxford radiographic decision aid safely and reliably identifies the appropriate patients for meniscal-bearing UKA and achieves good results in this population. The widespread use of this radiological decision aid should improve the results of UKA.

Skeletal Muscle Composition, Power, and Mitochondrial Energetics in Older Men and Women With Knee Osteoarthritis.

Our objective was to investigate the overall and sex-specific relationships between the presence and severity of knee osteoarthritis (KOA) and muscle composition, power, and energetics in older adults. Male and female patients (n = 655, mean ± SD age 76.1 ± 4.9 years; 57% female) enrolled in the Study of Muscle, Mobility, and Aging completed standing knee radiographs and knee pain assessments. Participants were divided into three groups using Kellgren-Lawrence grade (KLG) of KOA severity (0-1, 2, or 3-4). Outcome measures included whole-body muscle mass, thigh fat-free muscle (FFM) volume and muscle fat infiltration (MFI), leg power, specific power (power normalized to muscle volume), and muscle mitochondrial energetics. Overall, the presence and severity of KOA is associated with greater MFI, lower leg power and specific power, and reduced oxidative phosphorylation (P trend < 0.036). Sex-specific analysis revealed reduced energetics only in female patients with KOA (P trend < 0.007) compared to female patients without KOA. In models adjusted for age, sex, race, nonsteroidal anti-inflammatory drug administration, site or technician, physical activity, height, and participants with abdominal adiposity with KLG 3 to 4 had greater MFI (mean 0.008%, 95% confidence interval [CI] 0.004%-0.011%) and lower leg power (mean -51.56 W, 95% CI -74.03 to -29.10 W) and specific power (mean -5.38 W/L, 95% CI -7.31 to -3.45 W/L) than those with KLG 0 to 1. No interactions were found between pain and KLG status. Among those with KOA, MFI and oxidative phosphorylation were associated with thigh FFM volume, leg power, and specific power. Muscle health is associated with the presence and severity of KOA and differs by sex. Although muscle composition and power are lower in both male and female patients with KOA, regardless of pain status, mitochondrial energetics is reduced only in female patients.