Risk factors for knee osteoarthritis after traumatic knee injury: a systematic review and meta-analysis of randomised controlled trials and cohort studies for the OPTIKNEE Consensus

Quadriceps motor unit properties following ACL reconstruction are associated with corticospinal excitability and motor cortex activations

Quadriceps weakness is a primary concern following anterior cruciate ligament reconstruction (ACLR), and neuroimaging studies have revealed higher motor inhibition and structural atrophy of the corticospinal tract. To investigate the contributions of supraspinal mechanisms underlying spinal motoneuron impairments and quadriceps weakness, this study explored the firing patterns of motor units (MUs) in the vastus medialis muscle following ACLR. Twenty individuals with primary ACLR and 20 matched controls performed a unilateral knee extension torque-control task at 50% of maximal voluntary effort. High-density electromyographic activity of the vastus medialis muscle was decomposed into constituent MU action potentials. Electroencephalography was used to localize cortical activity to sensory and motor brain regions. Active motor thresholds were acquired using transcranial magnetic stimulation. We compared motor unit properties, cortical activity, and corticospinal excitability between groups and limbs using mixed-effects models and Cohen's d effect sizes. Participants with ACLR had weaker quadriceps compared with contralateral and control limbs. Strength deficits were accompanied by recruitment of larger MUs with lower firing rates in the involved limb. Those with ACLR also had lower corticospinal excitability and lower contralateral hemisphere motor cortex activations during quadriceps contractions. Lower corticospinal excitability and lower activations in the sensory and motor cortices were weakly associated with smaller MU action potential amplitudes, whereas group was not. Larger, slower-firing quadriceps MUs are recruited at lower absolute and mass-normalized recruitment thresholds, but not relative recruitment thresholds after ACLR. Lower corticospinal excitability and motor cortex activity were associated with the recruitment of smaller MUs irrespective of ACLR.NEW & NOTEWORTHY Individuals with anterior cruciate ligament reconstruction (ACLR) exhibited earlier recruitment of larger MUs with lower firing rates at both absolute and mass-normalized recruitment thresholds in their involved limb when compared with contralateral and control limbs. Individuals with ACLR had lower corticospinal excitability and lower contralateral hemisphere motor cortex activations, which were weakly associated with lower firing rates as larger motor units were recruited. Reduced excitatory cortical drive may contribute to quadriceps motor unit impairments and persistent quadriceps weakness after ACLR.

Posttraumatic Arthritis After Anterior Cruciate Ligament Injury: Machine Learning Comparison Between Surgery and Nonoperative Management

BACKGROUND

Nonoperative and operative management techniques after anterior cruciate ligament (ACL) injury are both appropriate treatment options for selected patients. However, the subsequent development of posttraumatic knee osteoarthritis (PTOA) remains an area of active study.

PURPOSE

To compare the risk of PTOA between patients treated without surgery and with ACL reconstruction (ACLR) after primary ACL disruption using a machine learning causal inference model.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A geographic database identified patients undergoing ACLR between 1990 and 2016 with minimum 7.5-year follow-up. Variables collected include age, sex, body mass index, activity level, occupation, relevant comorbid diagnoses, radiographic findings, injury characteristics, and clinical course. Treatment effects of ACLR on the development of PTOA and progression to total knee arthroplasty (TKA) were analyzed with machine learning models (MLMs) in a causal inference estimator (targeted maximum likelihood estimation, TMLE), while controlling for confounders.

RESULTS

The study included 1194 patients with a minimum follow-up of 7.5 years, among whom 974 underwent primary reconstruction and 220 underwent nonoperative treatment. A total of 215 (22%) patients developed symptomatic PTOA in the ACLR group compared with 140 (64%) in the nonoperative treatment group (P < .001), whereas 25 (3%) patients underwent TKA in the ACLR group compared with 50 (23%) in the nonoperative treatment group (P < .001). Patients in the ACLR group had delayed TKA compared with patients in the nonoperative treatment group (193.4 vs 166.0 months, respectively; P = .02). TMLE evaluation revealed that reconstruction decreased the risk of PTOA by 11% (95% CI, 8%-13%; P < .001) compared with nonoperative treatment but did not demonstrate a significant effect on the rate of progression to TKA. Survival analysis with random forest algorithm demonstrated significant delay to the onset of PTOA as well as time to progression of TKA in patients undergoing ACLR. Additional risk factors for the development of PTOA, irrespective of treatment, included older age at injury, greater body mass index, total number of arthroscopic knee surgeries, and residual laxity at follow-up.

CONCLUSION

MLMs in a causal inference estimator found ACLR to exert a significant treatment effect in reducing the rate of development of PTOA by 11% compared with nonoperative treatment. ACLR also delayed the onset of PTOA and progression to TKA.

A review of recent advances in tissue engineering scaffolds for meniscus repair

The meniscus, a critical load-bearing structure between the femur and the tibia, plays a key role in the functioning of the knee joint by distributing mechanical stress and minimizing friction. A brief overview of the anatomical characteristics and biomechanical functions of the meniscus is provided in this review, followed by a discussion of recent developments in tissue engineering scaffolds for meniscus repair over the past five years. The classification of scaffolds is based on the materials with an analysis of their respective advantages and limitations. The challenges associated with meniscal tissue engineering are summarized and potential research directions are proposed to guide the development of more effective regenerative strategies.

Osteoarthritis after major combat trauma: the Armed Services Trauma Rehabilitation Outcome Study

Objective

To investigate the differences in clinical and radiographic knee OA markers between injured and uninjured UK service personnel.

Methods

This study was a cross-sectional analysis, 8 years post-injury, of a prospective cohort study. The Knee Injury and Osteoarthritis Outcome Scores (KOOS), radiographic Kellgren and Lawrence (KL) scores and Osteoarthritis Research Society International scores (joint space narrowing, sclerosis, osteophytes) were obtained from 565 uninjured and 579 matched (on sex, age, rank, regiment and role on deployment) major combat injured participants from the Armed Services Trauma Rehabilitation Outcome study; 35 had a knee injury and 142 had an amputation without knee injury. Kruskal-Wallis tests were used to compare between groups for KOOS and radiographic measures. A multiple logistic regression was performed on the effects of injury on radiographic features.

Results

The mean age at injury was 25.7 years (s.d. 5.2). Injured participants demonstrated worse KOOS values for pain {median 89 [interquartile range (IQR) 72-100] vs 94 [83-100]} and symptoms [median 80 (IQR 60-90) vs 85 (70-95), P < 0.001] and higher scores for radiographic variables than uninjured participants. Injured non-amputated/non-knee-injured participants had worse KOOS values than uninjured participants [pain: 92 (IQR 75-100) vs 94 (83-100); symptoms: 80 (IQR 60-90) vs 85 (70-95), P < 0.01]. Knee-injured participants had worse KOOS values [pain: 67 (IQR 55-85), symptoms: 55 (IQR 35-73), P < 0.001] than all subgroups and worse radiographic measures than injured non-amputated participants. KL score (≥1) and sclerosis were worse for amputees than injured non-amputated participants. Amputees had 4.04-fold increased odds (95% CI 2.45, 6.65) vs uninjured participants and knee-injured participants had 4.06-fold increased odds (95% CI 1.89-8.74) than uninjured participants of knee osteoarthritis (KOA; KL ≥1). Injured participants (without knee injury/amputation) had 1.74-fold (95% CI 1.27, 2.69) increased odds of KOA than uninjured participants.

Conclusion

Major combat trauma (in addition to knee injury or amputation) has a substantial effect on the development of KOA.

Effect of intramuscular vs intra-articular betamethasone injection on pain and inflammatory factors among patients with severe traumatic knee osteoarthritis

OBJECTIVE

The aim of this study was to comprehensively investigate the clinical efficacy of intraoperative local joint injection and intramuscular injection of betamethasone in patients with severe traumatic knee osteoarthritis (KOA).

METHODS

80 patients with severe traumatic KOA undergoing total knee arthroplasty were retrospectively recruited and rolled into S1 group (intra-articular injection of ropivacaine + betamethasone and isotonic saline mixture at joint incision), S2 group (muscle local injection of betamethasone before incision closure, simultaneously intra-articular injection of ropivacaine + isotonic saline mixture at joint incision), and D group (intra-articular injection of ropivacaine + isotonic saline mixture at the joint incision). Visual analog scale (VAS) score, serum inflammatory factors (IFs), hospital for special surgery (HSS)score, Pittsburgh sleep quality index (PSQI), and adverse reaction events (AREs) were analyzed.

RESULTS

Pain scores of patients in all three groups decreased drastically over time on postoperative days (PDs) 1, 2, and 3, with the scores in S1 and S2 groups markedly inferior to D group (P < 0.05). HSS scores of patients in S1 and S2 groups at postoperative months 1, 3, and 6 were considerably superior to those in D group (P < 0.05). PSQI scores of patients in S1 and S2 groups at postoperative months 1, 3, and 6 were notably inferior to those in D group (P < 0.05).

CONCLUSION

Both intraoperative local joint injection and muscle injection of betamethasone are effective in patients with severe traumatic KOA.

Knee muscle strength and movement biomechanics in individuals with and without knee pain after anterior cruciate ligament reconstruction: A cross-sectional study

PURPOSE

Anterior cruciate ligament injury increases the risk of knee osteoarthritis, possibly via early onset of knee pain and changes in musculoskeletal function. This study compared knee muscle strength and movement biomechanics during walking and forward lunge between individuals with and without knee pain after anterior cruciate ligament reconstruction.

METHODS

Cross-sectional study including participants at least 3 years post anterior cruciate ligament reconstruction, aged 18-40 at the time of surgery, and body mass index ≤30. Symptomatic participants were defined by a knee pain score (reconstructed knee) of ≥3 on a 0-10 scale during activities of daily living in the past week. Asymptomatic participants were defined by a pain score of 0. Maximal isometric quadriceps and hamstring muscle strength (Nm/kg) and 3D walking, and forward lunge movement biomechanics were measured.

RESULTS

A total of 122 participants (30% females) were included: 33 symptomatic and 89 asymptomatic (average age: 33.7, range 23.7-51.3 years). The average post-surgery time was 6 (range 3-10) years. The symptomatic group exhibited lower isometric quadriceps and hamstring strength with mean group differences (95% confidence interval [CI]) of 0.33 (0.10 to 0.56) Nm/kg and 0.19 (0.07 to 0.31) Nm/kg, respectively. There were no important group differences in the walking and forward lunge movement biomechanics.

CONCLUSIONS

Symptomatic individuals with anterior cruciate ligament reconstruction demonstrated weaker knee muscles compared to their asymptomatic counterparts. The comparable walking and forward lunge biomechanics suggest that knee pain has no substantial impact on movement biomechanics up to 10 years post-surgery.

LEVEL OF EVIDENCE

Level III.

What Do Women (With Serious Knee Injury) Want to Know About Knee Health? Identifying Research Priorities With a Consumer Advisory Group

OBJECTIVES: To (1) establish a women's knee health consumer advisory group (CAG) via an evidence-informed process and (2) identify the CAG's research priorities to inform future projects. DESIGN: Mixed-methods priority-setting study. METHODS: The CAG was established, grounded in a participatory action research approach and using the Patient Engagement in Research Framework, to inform a 4-phase process: (1) understand, (2) plan, (3) undertake, and (4) evaluate. We identified the CAG's priorities for knee health research via a mixed-methods approach using the nominal group technique (NGT). We adopted a constructivist epistemology, using reflexive thematic analysis to construct codes and themes inductively. RESULTS: Six women (mean age of 35 years) joined the CAG, generating, reviewing, and discussing 70 ideas during NGT phases 1 to 3. We constructed 14 codes, grouped into 3 key themes: (1) best practice management and support for serious knee injury and rehabilitation, (2) social and gendered factors; and (3) physical, psychological, and personal factors. Voting and ranking (NGT phases 3-6) revealed the CAG's highest priority for future research was "Knowledge of, and access to specialised knee rehabilitation and practitioners." CONCLUSION: Establishing a CAG was an achievable and novel approach to identifying consumer priorities to enhance women's knee health outcomes. Women wanted improved access to information and best-practice care via genuine therapeutic relationships with practitioners who understand the gendered-social rehabilitation environment. J Orthop Sports Phys Ther 2025;55(2):1-14. Epub 15 January 2025. doi:10.2519/jospt.2025.12869.

Strength Setbacks: The Impact of Youth Sport-Related Knee Joint Injuries on Thigh Muscle Strength. A 24-Month Prospective Cohort Study

OBJECTIVE: To compare injured and uninjured limb knee extensor and flexor peak torque between youth who experienced a sport-related, traumatic knee joint injury and comparable uninjured youth, at baseline (≤4 months of injury) and semiannually for 2 years. Differences by injury type and sex were also explored. DESIGN: Prospective cohort study. METHODS: Bilateral knee extensor and flexor concentric isokinetic peak torque at 90° per second was assessed semiannually in 186 youth (106 injured, 80 controls) for 2 years. Between-group differences in strength over time were estimated with generalized estimating equations (95% confidence interval [CI]). Confounding was controlled using inverse probability weighting. Strength differences between those with anterior cruciate ligament (ACL) tears and those with non-ACL tear injuries as well as between male and female participants were explored. RESULTS: Compared to uninjured controls, injured limb knee extensor strength was lowest at baseline (-37.1 Nm; 95% CI, -45.3 to -28.9) and 6-month follow-up (-13.3 Nm; 95% CI, -20.4 to -6.2), with minimal strength gain beyond the 12-month follow-up (1.7 Nm; 95% CI, -14.3 to 17.6). Knee flexor strength of the injured limb was lowest at baseline (-24.6 Nm; 95% CI, -31.5 to -17.8), and there was minimal strength gain beyond 6 months (2.3 Nm; 95% CI, -7.7 to 12.3). The average residual deficit was similar to the knee extensors (10% to 11%) at 24 months. Exploratory analysis suggested no difference based on injury type or sex. CONCLUSION: Injured limb knee extensor and flexor weakness was present after different youth sport-related knee joint injuries. Strength deficits peaked early after injury, improved over time, and plateaued after 12 months, with lingering deficits at 24 months. Thigh muscle strength trajectory was similar across injury types and sex. J Orthop Sports Phys Ther 2025;55(2):1-11. Epub 20 December 2024. doi:10.2519/jospt.2024.12663.

High failure rate in meniscal repair when preceding anterior cruciate ligament reconstruction: An analysis of two-stage surgery for concomitant ACL injury and traumatic meniscus tear

PURPOSE

To investigate the failure rate, predictive factors associated with failure and clinical outcomes after a two-stage surgery; meniscus repair followed by subsequent anterior cruciate ligament (ACL) reconstruction (ACLR).

METHODS

Patients with a concomitant traumatic meniscus tear and ACL injury who underwent a two-stage surgery between January 2015 and January 2021 were identified. The primary outcome was meniscal repair failure, defined as a reoperation (re-repair or resection). A Cox-regression analysis was used in order to analyse factors associated with meniscal repair failure within 3 years after the primary surgery for a meniscal repair. Secondary outcomes were range of motion (ROM), anterior knee laxity and the Knee Injury and Osteoarthritis Outcome Score (KOOS) at 1- and 2-year follow-up. The thresholds of patient acceptable symptom state (PASS), treatment failure (TF) and minimum important change (MIC) were applied to KOOS4 (mean score of the KOOS Pain, Symptoms, Sports/Rec and QoL subscales).

RESULTS

A total of 150 patients were included. The meniscal repair failure rate after 3 years was 36.7%. Failure of meniscal repair was significantly associated with a time interval >1 year between the meniscal repair to the ACLR (hazard ratio [HR] = 2.5; 95% confidence interval [CI] = 1.2-5.5; p < 0.01), medial meniscus repair (HR = 2.3; 95% CI = 1.6-3.4; P < 0.01), and female sex (HR = 1.42; 95% CI = 1.0-1.9; p = 0.01). The age of the patient was not associated with meniscal repair failure. At the 6-month follow-up, most patients (72.5%) showed less than 2 mm of knee laxity; four patients (6.7%) experienced loss of extension and four patients (1.7%) experienced loss of flexion. On the KOOS4, at the 2-year follow-up, PASS was achieved in 53.4%, TF occurred in 1.7%, and MIC was reached in 36.4% of patients.

CONCLUSION

The meniscus repair failure rate after the staged procedure was 36.7% at 3 years. A longer time interval from meniscal repair to ACLR, medial meniscus repair, and female sex were associated with an increased risk of meniscal repair failure. Age was not associated with meniscal repair failure.

LEVEL OF EVIDENCE

Level IV case series retrospective study.

Effect of baseline values on inpatient rehabilitation outcomes after total knee arthroplasty: a retrospective observational study

OBJECTIVE

To compare inpatient rehabilitation outcomes after total knee arthroplasty (TKA) between groups with different baseline scores.

DESIGN

A retrospective observational study.

SUBJECTS

Patients with knee osteoarthritis who have previously undergone unilateral TKA.

METHODS

Patients participated in 3-week inpatient rehabilitation following TKA and were assessed for patient-reported outcome measures (PROMs), which included the Numeric Pain Rating Scale (NPRS), the Health Assessment Questionnaire (HAQ), the European Quality of Life 5 Dimensions 5 Level Version (EQ-5D-5L), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Furthermore, mobility scores for the range of motion (ROM) and the Timed Up and Go (TUG) test were recorded at the beginning and the end of rehabilitation. Patients were divided into quartile groups based on their initial examination scores.

RESULTS

329 patients were enrolled in the study. The study population consisted mostly of female patients (63.8% vs 36.2%) with a mean age of 68.25 (SD 9.24) years. The personalized 21-day in rehabilitation programme was safe for all patients and had no dropouts. Patients with better PROMs scores at T1 did not have the same potential for improvement in PROMs but showed effective improvement in mobility (η² = 0.103 for changes in the WOMAC vs η²=0.502 for changes in the TUG test).

CONCLUSION

Regardless of the baseline scores, all patients presented significant improvements in both subjective and objective measures. Age and baseline PROMs or mobility scores did not have a significant effect on score development.

Therapeutic Controlled Release Strategies for Human Osteoarthritis

Osteoarthritis is a progressive, irreversible debilitating whole joint disease that affects millions of people worldwide. Despite the availability of various options (non-pharmacological and pharmacological treatments and therapy, orthobiologics, and surgical interventions), none of them can definitively cure osteoarthritis in patients. Strategies based on the controlled release of therapeutic compounds via biocompatible materials may provide powerful tools to enhance the spatiotemporal delivery, expression, and activities of the candidate agents as a means to durably manage the pathological progression of osteoarthritis in the affected joints upon convenient intra-articular (injectable) delivery while reducing their clearance, dissemination, or side effects. The goal of this review is to describe the current knowledge and advancements of controlled release to treat osteoarthritis, from basic principles to applications in vivo using therapeutic recombinant molecules and drugs and more innovatively gene sequences, providing a degree of confidence to manage the disease in patients in a close future.

Early Intervention With Boiogito to Suppress Knee Osteoarthritis Progression: An Experimental Approach Using a Medial Meniscus Instability Rat Model

Background Knee osteoarthritis (KOA) is a prevalent and chronic condition characterized by swelling, pain, and limited range of motion of the knee due to degenerative changes in joint structures, leading to impairment in performing daily activities. Although conservative treatments, such as exercise therapy and nonsteroidal anti-inflammatory drugs are employed, there are few effective therapeutic options for preventing disease progression. During early KOA, there is osteoclast proliferation in the subchondral bone, disruption in cartilage homeostasis, elevation of matrix metalloproteinase-13 (MMP-13) levels, and reduction in tissue inhibitors of matrix metalloproteinase-1 (TIMP-1) levels. Boiogito (BOT), which is a traditional Japanese medicinal formula, attenuates KOA progression, however, its effects when administered after KOA progression remain unclear. This study aimed to assess the therapeutic efficacy of BOT in preventing KOA progression in a rat model by focusing on its effects on motor function, subchondral bone turnover, and cartilage degradation in relation to the timing of administration. Methods A rat KOA model was created by destabilizing the medial meniscus (DMM). Rats were divided into Sham, DMM, DMM + BOT (0w, BOT administered immediately post-surgery), and DMM + BOT (3w, BOT administered 3 weeks post-surgery) groups. BOT was included in the diet at 1% (w/w). Motor function was evaluated biweekly by a treadmill running test, while structural changes in the knee were assessed by measuring the medial meniscus extrusion ratio (MMER) using computed tomography (CT). Histological and immunohistochemical analyses were conducted to evaluate joint degeneration via the Osteoarthritis Research Society International (OARSI) score, osteoclast numbers in subchondral bone through tartrate-resistant acid phosphatase (TRAP) staining, and MMP-13/TIMP-1 ratios in articular cartilage. Results Treadmill testing revealed that the DMM + BOT (0w) had significantly higher running speeds compared with the DMM and DMM + BOT (3w) groups. In all groups that underwent DMM surgery, the MMER was not significantly different. Histological assessments showed that the DMM + BOT (0w) group had lower OARSI scores and reduced osteoclast numbers in the subchondral bone compared with the DMM group. Immunohistochemical analysis showed a significant reduction in MMP-13 expression and MMP-13/TIMP-1 ratios in the DMM + BOT (0w) group, whereas the DMM + BOT (3w) group showed limited efficacy compared with the early intervention. Conclusion Early administration of BOT attenuates KOA progression by preserving motor function, reducing subchondral bone turnover, and mitigating cartilage degradation. These findings highlight the importance of early intervention with BOT to achieve optimal therapeutic outcomes in KOA.

Osteoarthritis year in review 2024: Biology

Osteoarthritis (OA) research is a fast-growing and extremely wide field, in which a substantial increase in knowledge has been achieved over the last year. It covers many different topics, however, a PubMed search using the terms 'osteoarthritis' and 'biology' resulted in only a limited number of studies that were published between April 2023 and April 2024. In order to identify OA-relevant studies that focus on mechanistic studies of biological processes at the tissue, cellular, and molecular level, the following keywords were included as search terms: tissue interactions, single cell sequencing, transcriptomics, extracellular matrix, signaling, ion channels, and pain. The final selection of publications presented in this 'year in review' was influenced by the personal preferences of the authors, and eventually three larger key themes emerged: 1) Joint tissue interactions covering meniscus, subchondral bone, fat tissue, synovium, and synovial fluid. 2) Degeneration of the cartilage extracellular matrix and generation of bioactive fragments. 3) Receptors, ion channels, signaling pathways, and cellular metabolism. Many of the studies summarized here identified novel potential targets for OA treatment, and promising results were already obtained addressing these targets in different animal models. It will be exciting to see which findings can be translated into future clinical studies and eventually lead to novel treatment approaches for human OA.

Twenty year analysis of professional men's rugby union knee injuries from the English premiership shows high rates and burden

OBJECTIVES

To determine the rates, severity and burden of knee injuries in professional male rugby union from the English Premiership.

METHODS

Injury and exposure data were captured over 20 seasons using a prospective cohort design. Knee injury incidence, days' absence and burden were recorded for each injury type and by pitch surface type for match and training.

RESULTS

The rate of knee injury in matches was 9.8/1000 hours (95% CIs 9.3-10.3). Mean days lost were 50 (95% CI 46 to 53) in matches and 51 (95% CI 44 to 57) in training. In matches, medial collateral ligament injuries were the most common, while anterior cruciate ligament (ACL) injuries had the highest mean severity and burden. There was no significant change in the count of knee injuries over time; however, average severity increased significantly (annual change: 2.18 days (95% CI 1.60 to 2.77); p<0.001). The incidence of match knee injury was 44% higher on artificial pitches than grass pitches (incidence rate ratio: 1.44 (95% CI 1.21 to 1.69); p<0.01), with no significant difference in severity between surfaces. In matches, the tackle was the event most commonly associated with knee injuries for all diagnoses, except ACL injuries (running). In training, running was a more common injury event than the tackle.

CONCLUSION

Knee injuries in matches are common and severe in English professional men's rugby union. Despite an increased focus on player conditioning and injury prevention throughout the study period, rates of knee injury remained stable, and resulting days' absence increased. New strategies for the prevention of knee injuries should be considered a priority.

Posttraumatic hyperalgesia and associated peripheral sensitization after temporomandibular joint injury in mice

ABSTRACT

Temporomandibular disorder (TMD) is the most prevalent painful condition in the craniofacial area. Recent studies have suggested that external or intrinsic trauma to the temporomandibular joint (TMJ) is associated with the onset of painful TMD in patients. Here, we investigated the effects of TMJ trauma through forced-mouth opening (FMO) in mice to determine pain behaviors and peripheral sensitization of trigeminal nociceptors in both sexes. Forced-mouth opening increased mechanical pain as assessed by the von Frey test, with spontaneous pain-like behaviors assessed using the mouse grimace scale and anxiety-like behaviors assessed using the open-field test. Changes in pain-like behaviors were not different between male and female mice. However, in vivo GCaMP Ca2+ imaging of intact trigeminal ganglia (TG) showed modality- and sex-dependent changes. Forced-mouth opening increased spontaneous Ca2+ responses and mechanical hypersensitivity of TG neurons compared to the sham group, which was more pronounced in male mice. Forced-mouth opening also increased Ca2+ responses evoked by cold, heat, and capsaicin stimuli, which was not different between the sexes. In retrogradely labeled trigeminal TMJ afferents, FMO induced an increase in small-sized neuronal proportions with increased colocalization with calcitonin gene-related peptides and transient receptor potential vanilloid subtype 1, which was modestly sex dependent. These results suggest that TMJ injury leads to persistent posttraumatic hyperalgesia associated with peripheral sensitization of trigeminal nociceptors with distinct sex dependency.

Association of serum biomarkers with radiographic knee osteoarthritis, knee pain and function in a young, male, trauma-exposed population - Findings from the ADVANCE study

OBJECTIVE

The ArmeD SerVices TrAuma RehabilitatioN OutComE (ADVANCE) study is investigating long-term combat-injury outcomes; this sub-study aims to understand the association of osteoarthritis (OA) biomarkers with knee radiographic OA (rOA), pain and function in this high-risk population for post-traumatic OA.

DESIGN

ADVANCE compares combat-injured participants with age, rank, deployment and job-role frequency-matched uninjured participants. Post-injury immunoassay-measured serum biomarkers, knee radiographs, Knee Injury and Osteoarthritis Outcome Scale, and six-minute walk tests are reported. The primary analysis, adjusted for age, body mass, socioeconomic status, and ethnicity, was to determine any differences in biomarkers between those with/without combat injury, rOA and pain. Secondary analyses were performed to compare post-traumatic/idiopathic OA, painful/painfree rOA and injury patterns.

RESULTS

A total of 1145 male participants were recruited, aged 34.1 ± 5.4, 8.9 ± 2.2 years post-injury (n = 579 trauma-exposed, of which, traumatic-amputation n = 161) or deployment (n = 566 matched). Cartilage oligomeric matrix protein (COMP) was significantly higher in the combat-injured group compared to uninjured (p = 0.01). Notably, COMP was significantly lower in the traumatic-amputation group compared to non-amputees (p < 0.001), decreasing relative to number of amputations (p < 0.001). Leptin was higher (p = 0.005) and adiponectin lower (p = 0.017) in those with v without knee pain, associated with an increased risk of 22% and 17% for pain, and 46% and 34% for painful rOA, respectively. There were no significant differences between trauma-exposed and unexposed participants with rOA.

CONCLUSIONS

The most notable findings of this large, unique study are the similarities between those with rOA regardless of trauma-exposure, the injury-pattern and traumatic-amputation-associated differences in COMP, and the relationship between adipokines and pain.

The Molecular Mechanism Investigation of HBP-A Slows Down Meniscus Hypertrophy and Mineralisation by the Damage Mechanical Model

HBP-A is the main active component of a traditional Chinese medicine Huaizhen Yanggan Capsule, for the remarkable treatment of knee osteoarthritis (KOA). This study aimed to elucidate the ameliorative effect of HBP-A on meniscus hypertrophy and mineralisation in KOA and the molecular mechanism of its action. An Hartley guinea pig model of KOA that underwent anterior cruciate ligament transection (ACLT) and a model of rat primary meniscus fibrochondrocytes (PMFs) were used to investigate the ameliorative effect of HBP-A on meniscal hypertrophy and calcification and its signal transduction mechanism of action. The results show that Guinea pig's meniscus width, as well as the area of meniscus calcification and meniscus and articular cartilage injury score, were significantly reduced in the HBP-A intervention group compared to the ACLT group. The expression levels of mtrix metalloproteinase 13 (MMP13), runt-related transcription factor 2 (Runx2), Indian hedgehog (Ihh), alkaline phosphatase (ALP), and ankylosis homologue (ANKH) at the protein and gene level significantly decreased in the HBP-A intervention group compared to the ACLT group. In vitro study, apoptosis, hypertrophy, and calcification of rat PMFs after 10% stretch force were significantly improved with HBP-A intervention. Western blot and RT-qPCR showed that hypertrophy, calcification, and p38 MAPK signalling pathway-related markers of PMFs were incredibly depressed in the HBP-A intervention group compared to the 10% stretch force group. In conclusion, HBP-A can slow down meniscus hypertrophy and mineralisation induced by abnormal mechanical loading, and its mechanism of action may be through the p38-MAPK signalling pathway.

β2-adrenoceptors kick osteoarthritis - Time to rethink prevention and therapy

Although, during the past decades, substantial advances emerged in identifying major local and systemic factors contributing to initiation and progression of osteoarthritis (OA), some neuroendocrine mechanisms are still not understood or even neglected when thinking about novel therapeutic options. One of which is the sympathetic nervous system that exhibits various OA-promoting effects in different tissues of the joint. Interestingly, the β2-adrenoceptor (AR) mediates the majority of these effects as demonstrated by several in vitro, in vivo as well as in clinical studies. This review article does not only summarize studies of the past two decades demonstrating that the β2-AR plays an OA-promoting role in different tissues of the joint but also aims to encourage the reader to think about next-level research to discover novel and innovative preventive and/or therapeutic strategies targeting the β2-AR in OA.

Anterior Cruciate Ligament Reconstruction and Concomitant Focal Cartilage Lesions: A Systematic Review and Meta-Analysis of Prognosis after Surgical Treatment

OBJECTIVE

To synthesize available evidence on the impact of concomitant focal cartilage lesions and their surgical treatment on clinical outcomes in the setting of anterior cruciate ligament (ACL)-reconstruction at short (6-36 months) and midterm (3-8 years) follow-up.

DESIGN

Original level 1 or 2 studies comparing any patient-reported or objective outcomes in ACL-reconstructed patients (1) with and without concomitant focal cartilage lesion(s) or (2) after any type of cartilage surgical treatment were considered for inclusion. Systematic searches were conducted in MEDLINE via Ovid, Cochrane Library, EMBASE via OvidSP, and Web of Science.

RESULTS

In meta-analysis performed across 6 studies (n=8,789 patients), we discovered with very low certainty, the correlation of concomitant any-thickness cartilage lesions and worse Patient-Reported Outcome Measure scores (PROMS) at cumulative short to mid, (pooled standardized mean difference (psmd) = -0.36; 95% confidence interval (CI) -0.62 to -0.10), short (psmd = -0.43; 95% CI = -0.94 to 0.08), and midterm (psmd = -0.22; 95% CI -0.43 to 0.00). Full-thickness lesions predicted worse PROMS with moderate certainty at cumulative short-midterm (psmd = -0.32; 95% CI = -0.41 to -0.23) and low certainty at both short (psmd = -0.45; 95% CI -0.83 to -0.07) and midterm (psmd = -0.30; 95% CI -0.38 to -0.22). In 4 studies for each outcome, mixed results were reported on osteoarthritis (OA) and reoperation rates.

CONCLUSIONS

As the main finding, concomitant full-thickness cartilage lesions in ACL-reconstructed patients are a predictor of worse PROMS in the cumulative short to midterm. Correlations of any-thickness lesions or different cartilage treatments with short- or midterm PROMS, OA, or reoperation rates were either with very low certainty, unmeasured, or with mixed results.

Knee joint pathology and efferent pathway dysfunction: Mapping muscle inhibition from motor cortex to muscle force

BACKGROUND

Dysfunction in efferent pathways after knee pathology is tied to long-term impairments in quadriceps and hamstrings muscle performance, daily function, and health-related quality of life. Understanding the underlying etiology is crucial for effective treatment and prevention of poor outcomes, such as post-traumatic osteoarthritis or joint replacement.

OBJECTIVES

To synthesize recent evidence of efferent pathway dysfunction (i.e., motor cortex, motor units) among individuals with knee pathology.

DESIGN

Commentary.

METHOD

We summarize the current literature investigating the motor cortex, corticospinal tract, and motoneuron pool in individuals with three common knee pathologies: anterior cruciate ligament (ACL) injury, anterior knee pain (AKP), and knee osteoarthritis (OA). To offer a complete perspective, we draw from studies applying a range of neuroimaging and neurophysiologic techniques.

RESULTS

Adaptations within the motor cortices, corticospinal tract, and motoneuron pool are present in those with knee pathology and underline impairments in quadriceps and hamstrings muscle function. Each pathology has evidence of altered motor system excitability and reduced volitional muscle activation and force-generating capacity, but few impairments were common across ACL injury, AKP, and OA studies. These findings underscore the central role of the motor cortex and motor unit behavior in the long-term outcomes of individuals with knee pathology.

CONCLUSIONS

Adaptations in the efferent pathways underlie persistent muscle dysfunction across three common knee pathologies. This review provides an overview of these changes and summarizes key findings from neurophysiology and neuroimaging studies, offering direction for future research and clinical application in the rehabilitation of joint injuries.

Ankle, knee and concussion concerns: Unveiling injury patterns in highly trained South African netball players

OBJECTIVES

To describe the rate and type of netball injuries sustained during women's university-level tournament matches in South Africa.

DESIGN

Descriptive epidemiological study.

SETTING

Three editions of the women's Varsity Netball tournament (2021-23).

PARTICIPANTS

Student-athletes representing nine university women's teams.

MAIN OUTCOME MEASURES

Medical attention match injuries prospectively recorded by team medical staff. Injuries were classified according to the 2020 consensus statement, with the addition of "concussion" as a separate pathology type. The main outcomes are reported as incidence (injuries per 1000h; 95% confidence intervals - CIs), burden (days lost per 1000h; 95%CIs), and frequency (% of all injuries).

RESULTS

Sixty-three injuries were recorded from 48 different players (58.8 per 1000h; 45.2-75.3) and the overall injury burden was 401 days per 1000h (364-440). Injury incidence by pathology type was highest for joint sprains (28.9 per 1000h), tendinopathies (7.5 per 1000h), and concussions (4.7 per 1000h). Joint sprains to the ankle accounted for 49% of the overall estimated days lost.

CONCLUSIONS

Ankle joint sprains should be the primary target of injury risk reduction programmes in highly trained netball players. Concussions were reported and efforts should be made to increase awareness among players, coaches and medical staff.

The effect of depression status on osteoarthritis: A powerful two-step Mendelian randomization study

Osteoarthritis (OA) is a common degenerative disease that affects millions of individuals worldwide.

OBJECTIVE

There is no conclusive epidemiological evidence regarding the relationship between OA, depression, and whole-body fat mass. In this study, we conducted a two-step Mendelian randomization analysis to determine the causal relationships between them.

DESIGN

The published summary-level data are from genome-wide association studies (GWAS). Our study included 357,957 samples and 10,828,862 SNPs. Finally, the outcome GWAS data for OA came from a GWAS on the genetic architecture of OA using UK Biobank data. This study included 50,508 samples and 15,845,511 SNPs. We used five different modes of analysis, including inverse variance weighted meta-analysis (IVW), MR-Egger regression, weighted median, simple mode, and weighted mode, to explore causal relationships.

RESULTS

We found a positive correlation between depression and body fat mass, with depression leading to body fat mass an increase in (IVW result: p = 3.39E-07, OR (95 % CI) =2.16 (1.61, 2.90)). We also found a positive correlation between body fat mass and OA, with body fat mass increasing the risk of OA (IVW result: p = 1.65E-33, OR (95 % CI) = 1.98 (1.77, 2.21). Body fat mass played an important role as a mediator in the causal relationship between depression and OA, with approximately 14 % of the risk of OA caused by depression being mediated by body fat mass.

CONCLUSIONS

Our study offers reliable evidence that depression has a detrimental impact on the risk of OA. Future research can support these associations from improving depressed effect, including social, biological, and behavioral factors, to reduce the risk of chronic diseases such as osteoarthritis. And we identified high-risk variation of alleles which associated with OA and depression can be used to predict disease and provide a basis for clinical intervention and treatment of OA.

Prevention of Post-Traumatic Osteoarthritis in the Military: Relevance of OPTIKNEE and Osteoarthritis Action Alliance recommendations

Musculoskeletal injury (MSKI) is the most common reason for short-term occupational limitation and subsequent medically related early departure from the military. MSKI-related medical discharge/separation occurs when service personnel are unable to perform their roles due to pain or functional limitations associated with long-term conditions, including osteoarthritis (OA). There is a clear link between traumatic knee injuries, such as anterior cruciate ligament or meniscal, and the development of post-traumatic OA (PTOA). Notably, PTOA is the leading cause of disability following combat injury. Primary injury prevention strategies exist within the military, with interventions focused on conditioning, physical health and leadership. However, not every injury can be prevented, and there is a need to develop secondary prevention to mitigate or reduce the risk of PTOA following an MSKI. Two international collaborative groups, OPTIKNEE and OA Action Alliance, recently produced rigorous evidence-based consensus statements for the secondary prevention of OA following a traumatic knee injury, including consensus definitions and clinical and research recommendations. These recommendations focus on patient-centred lifespan interventions to optimise joint health and prevent lost decades of care. This article aims to describe their relevance and applicability to the military population and outline some of the challenges associated with service life that need to be considered for successful integration into military care pathways and research studies.

Causal impact of statins on susceptibility to osteoarthritis: insights from a two-sample Mendelian randomization analysis

BACKGROUND

Osteoarthritis is a widely prevalent cause of pain and disability among older adults. It is an incurable condition, and most treatments are aimed at alleviating symptoms.

AIM

This study aimed to investigate the impact of statins on osteoarthritis by using a two-sample Mendelian randomization approach, using genetic variants associated with statin use as instrumental variables.

METHOD

Information on single nucleotide polymorphisms associated with statin medication was obtained from the FinnGen study, and data on osteoarthritis were sourced from the UK Biobank. The inverse variance weighted method was used as the primary analytical approach for the Mendelian randomization analysis. Sensitivity analyses were conducted to evaluate horizontal pleiotropy and heterogeneity. To examine the genetic relationship between statins and osteoarthritis, linkage disequilibrium score regression-based estimates were used.

RESULTS

Mendelian randomization analysis indicated a positive effect of statin use on the treatment of osteoarthritis (odds ratio 0.951, 95% confidence interval 0.914-0.99, p < 0.05). This conclusion was supported by various Mendelian randomization methods. Sensitivity analyses revealed no significant directional pleiotropy or influential single nucleotide polymorphisms that could compromise the overall causal inference. Linkage disequilibrium score regression-based estimates suggested a modest genetic correlation between statin use and osteoarthritis (Rg = 0.098, Se = 0.034, p < 0.05), thus reinforcing the robustness of the Mendelian randomization analysis.

CONCLUSION

Statins reduce the risk of osteoarthritis, aligning with the results of observational studies. Further research is essential to validate these results and explore the underlying mechanisms in detail.

A New Tissue Engineering Strategy to Promote Tendon-bone Healing: Regulation of Osteogenic and Chondrogenic Differentiation of Tendon-derived Stem Cells

In the field of sports medicine, repair surgery for anterior cruciate ligament (ACL) and rotator cuff (RC) injuries are remarkably common. Despite the availability of relatively effective treatment modalities, outcomes often fall short of expectations. This comprehensive review aims to thoroughly examine current strategies employed to promote tendon-bone healing and analyze pertinent preclinical and clinical research. Amidst ongoing investigations, tendon-derived stem cells (TDSCs), which have comparatively limited prior exploration, have garnered increasing attention in the context of tendon-bone healing, emerging as a promising cell type for regenerative therapies. This review article delves into the potential of combining TDSCs with tissue engineering methods, with ACL reconstruction as the main focus. It comprehensively reviews relevant research on ACL and RC healing to address the issues of graft healing and bone tunnel integration. To optimize tendon-bone healing outcomes, our emphasis lies in not only reconstructing the original microstructure of the tendon-bone interface but also achieving proper bone tunnel integration, encompassing both cartilage and bone formation. In this endeavor, we thoroughly analyze the transcriptional and molecular regulatory variables governing TDSCs differentiation, incorporating a retrospective analysis utilizing single-cell sequencing, with the aim of unearthing relevant signaling pathways and processes. By presenting a novel strategy rooted in TDSCs-driven osteogenic and chondrogenic differentiation for tendon-bone healing, this study paves the way for potential future research avenues and promising therapeutic applications. It is anticipated that the findings herein will contribute to advancing the field of tendon-bone healing and foster the exploration of TDSCs as a viable option for regenerative therapies in the future.

Exploring the Causal Relationship between Ibuprofen Use and Osteoarthritis Risk: A Mendelian Randomization Study

This study explored the potential causal relationship between ibuprofen (IBU) use and the risk of developing osteoarthritis, a prevalent joint disorder characterized by pain and stiffness. We conducted a two-sample MR analysis using four distinct OA GWAS datasets as outcomes and single-nucleotide polymorphisms (SNPs) associated with IBU metabolism as exposures. The inverse variance weighted (IVW) and weighted median methods were utilized to assess the causal association by meta-analysis, while pleiotropy and heterogeneity were evaluated using MR-Egger regression and Cochran's Q statistics. The MR analysis provided strong evidence for a causal association between IBU use and an increased risk of OA. A meta-analysis of the IVW and weighted median results across all datasets demonstrated an OR = 1.116 (95% CI = 1.063-1.170) and an OR = 1.110 (95% CI = 1.041-1.184). The consistency of the results obtained from different methods enhanced the reliability of the findings. Low pleiotropy and minimal heterogeneity were observed, further validating the results. The study supports a causal link between IBU use and an increased risk of OA, suggesting that IBU may accelerate the progression of OA while relieving symptoms. These findings highlight the importance of cautious use of IBU in clinical practice, especially considering its potential impact on long-term joint health.

Knowledge mapping and bibliometric analysis of medical knee magnetic resonance imaging for knee osteoarthritis (2004-2023)

Objectives

Magnetic resonance imaging (MRI) is increasingly used to detect knee osteoarthritis (KOA). In this study, we aimed to systematically examine the global research status on the application of medical knee MRI in the treatment of KOA, analyze research hotspots, explore future trends, and present results in the form of a knowledge graph.

Methods

The Web of Science core database was searched for studies on medical knee MRI scans in patients with KOA between 2004 and 2023. CiteSpace, SCImago Graphica, and VOSviewer were used for the country, institution, journal, author, reference, and keyword analyses.

Results

A total of 2,904 articles were included. The United States and Europe are leading countries. Boston University is the main institution. Osteoarthritis and cartilage is the main magazine. The most frequently cocited article was "Radiological assessment of osteoarthrosis". Guermazi A was the author with the highest number of publications and total references. The keywords most closely linked to MRI and KOA were "cartilage", "pain", and "injury".

Conclusions

The application of medical knee MRI in KOA can be divided into the following parts: (1). MRI was used to assess the relationship between the characteristics of local tissue damage and pathological changes and clinical symptoms. (2).The risk factors of KOA were analyzed by MRI to determine the early diagnosis of KOA. (3). MRI was used to evaluate the efficacy of multiple interventions for KOA tissue damage (e.g., cartilage defects, bone marrow edema, bone marrow microfracture, and subchondral bone remodeling). Artificial intelligence, particularly deep learning, has become the focus of research on MRI applications for KOA.

A Comparison of Proximal Patellar Realignment vs. Medial Patellofemoral Ligament Reconstruction: A Review of the Literature

» Patellar instability is challenging to address, and although there are many surgical options, proximal patellar realignment (PPR) and medial patellofemoral ligament (MPFL) reconstruction are both used-recently, the MPFL reconstruction has become more popularized.» Both procedures have demonstrated similar recurrent dislocation rates and rates of arthritic progression.» PPR is a cost-efficient procedure using just suture alone as compared with MPFL reconstruction, which uses different grafts and methods of fixation.» PPR has demonstrated durable results, with a lower overall complication rate, much of which is caused by the MPFL reconstruction having unique complications due to fixation methods.» The PPR is a beneficial procedure and should still be considered when dealing with patellar instability.

Validity, Agreement and Reliability of the ForceFrame Dynamometer in Patients with Anterior Cruciate Ligament Injury

Background

Restoring maximal muscle strength of the knee extensors (KE) and knee flexors (KF) following anterior cruciate ligament (ACL) injury and ACL reconstruction is of great importance to reduce the re-injury rate after ACL reconstruction and to reduce the risk of knee osteoarthritis. Therefore, it is essential that clinicians and healthcare providers use valid and reliable measures to assess knee muscle strength to ensure a safe return to sport.

Purpose

To evaluate the reliability (test-retest reliability, inter-tester reliability and test-retest agreement) and validity (concurrent validity, convergent validity and ForceFrame (FF) vs. isokinetic dynamometer (ID) agreement) of the ForceFrame (FF) dynamometer during isometric testing of the knee extensors and flexors.

Study Design

Cross-sectional study.

Material and Methods

Twenty-seven participants with ACL injury or reconstruction were recruited for participation in this study. maximal voluntary isometric contration (MVIC) of the knee extensors and flexors was tested on two separate days. Day one included validity assessments with FF, a gold-standard ID and a handheld dynamometer (HHD). Day two included reliability assessments with FF performed by two assessors. Main outcome measures were day-to-day test-retest reliability and agreement and inter-tester reliability of FF, and concurrent validity (FF vs. an ID and a HHD). Reliability was tested as test-retest and inter-tester reliability using interclass correlation coefficient (ICC), while agreement was tested using Bland & Altman plots with limits of agreement (LOA), standard error of measurement (SEM) and smallest detectable change (SDC). Concurrent validity between FF, ID, and HHD was assessed using Pearson's correlations and mean difference was evaluated by Bland & Altman plots.

Results

Twenty-seven participants (10 females, 17 males) with a median age of 25 years (range 19-60) were included in this study. There was a good day-to-day test-retest reliability for MVIC of KE (ICC=0.77, CI95:0.48-0.90) and KF (ICC=0.83, CI95:0.61-0.92) and excellent inter-tester reliability for MVIC of KE (ICC=0.97, CI95:0.94-0.98) and KF (ICC=0.93, 95CI:0.85-0.97). Standard error of measurement (SEM) was 8% and 9%, while the smallest detectable change (SDC) was 22% and 27% for KE and KF, respectively. FF showed fair concurrent validity compared to ID for KE (r=0.56), poor concurrent validity for knee flexors (KF (r=0.24) and compared to HHD a moderate correlation for KE (r=0.74) and poor correlation for KF (r=0.12). Bland & Altman plots between FF and the ID showed a mean difference of -0.51 Nm/kg for KE and -0.32Nm/kg for KF.

Conclusions

FF can be used to obtain reliable and valid results to assess MVIC of the KE, but not the KF. It should be noted that absolute results produced by the FF may be considered an underestimation of actual MVIC. The test position to assess KF in FF does not appear to be optimal, and different test-positions may be considered.

Level of evidence

Level 3.

Cartilage compositional MRI-a narrative review of technical development and clinical applications over the past three decades

Articular cartilage damage and degeneration are among hallmark manifestations of joint injuries and arthritis, classically osteoarthritis. Cartilage compositional MRI (Cart-C MRI), a quantitative technique, which aims to detect early-stage cartilage matrix changes that precede macroscopic alterations, began development in the 1990s. However, despite the significant advancements over the past three decades, Cart-C MRI remains predominantly a research tool, hindered by various technical and clinical hurdles. This paper will review the technical evolution of Cart-C MRI, delve into its clinical applications, and conclude by identifying the existing gaps and challenges that need to be addressed to enable even broader clinical application of Cart-C MRI.

Can tests of physical fitness predict traumatic knee injury in youth female athletes? A prospective cohort study

OBJECTIVES

To compile a battery of test including various aspects of physical fitness that could be used on the field and to assess whether any of these tests are associated with future traumatic knee injuries in youth female team sports athletes.

DESIGN

Prospective cohort.

SETTING

Sport setting.

PARTICIPANTS

Female athletes (n = 117, age 15-19 years), from Swedish sport high schools, active in soccer, handball, or floorball.

MAIN OUTCOME MEASURES

Differences in pre-injury tests values of 11 physical fitness tests in injured versus non-injured athletes, assessed as number of traumatic knee injuries over one season.

RESULTS

28 athletes sustained 34 traumatic knee injuries. Athletes who sustained an injury had a shorter distance on the Yo-Yo IR1 test at baseline than those without an injury (mean difference -193 m, CI -293- -65 m). None of the other tests, assessed for muscular strength, endurance, power, flexibility and dynamic knee valgus, differed between injured and non-injured athletes.

CONCLUSIONS

Youth female athletes with lower intermittent endurance capacity, assessed with the Yo-Yo IR1, seemed to be at greater risk of traumatic knee injury. Neither hop performance, flexibility, dynamic knee valgus nor isolated strength tests at baseline could distinguish between injured and non-injured youth female athletes at follow-up.

Efficacy of a Novel Telehealth Application in Health Behavior Modification and Symptomology in Military Service Members at Risk for Post-traumatic Osteoarthritis

INTRODUCTION

Mobile applications (apps) may be beneficial to promote self-management strategies to mitigate the risk of developing post-traumatic osteoarthritis in military members following a traumatic knee injury. This study investigated the efficacy of a mobile app in facilitating behavior modification to improve function and symptomology among military members.

MATERIALS AND METHODS

This is a preliminary pre and post hoc analysis of a randomized control trial. The MARX scale, Intermittent and Constant Osteoarthritis Pain (ICOAP) questionnaire, and the Knee Injury and Osteoarthritic Outcome Score Readiness to Manage Osteoarthritis Questionnaire were completed at baseline, 6-week, 6-month, and 12-month follow-up. Participants in the treatment arm completed the System Usability Scale. Data were analyzed using descriptive statistics, the Wilcoxon sum of ranks test, the Wilcoxon signed-rank test, and Cohen's d effect size.

RESULTS

A total of 28 participants were included. Between-group differences for baseline and 6-week follow-up were significantly improved in the injured knee ICOAP constant pain score for the treatment group (treatment: -4.2 ± 12, 95% CI: -11.5, 3.1; control: 5.5 ± 9.9, 95% CI: 0.9, 10.1; P = .035, effect size = 0.905). Within-group differences for baseline and 6-week follow-up demonstrated a significant decline in the injured knee ICOAP constant pain score among the control group (signed-rank: 16.0, P = .031, Cohen's d = 0.339). No other significant differences were observed. A good System Usability Scale score for usability was found (76.6 ± 8.8).

CONCLUSIONS

These results indicate that the mobile app is easy to use and may contribute to improved constant pain symptomology for patients at risk for post-traumatic osteoarthritis.

Surgical Therapy and Tissue Engineering for Meniscal Repair

Meniscal damage is one of the prevalent causes of knee pain, swelling, instability, and functional compromise, frequently culminating in osteoarthritis (OA). Timely and appropriate interventions are crucial to relieve symptoms and prevent or delay the onset of OA. Contemporary surgical treatments include total or partial meniscectomy, meniscal repair, allograft meniscal transplantation, and synthetic meniscal implants, but each presents its specific limitations. Recently, regenerative medicine and tissue engineering have emerged as promising fields, offering innovative prospects for meniscal regeneration and repair. This review delineates current surgical methods, elucidating their specific indications, advantages, and disadvantages. Concurrently, it delves into state-of-the-art tissue engineering techniques aimed at the functional regenerative repair of meniscus. Recommendations for future research and clinical practice are also provided.

Patient and Operative Risk Factors for Osteoarthritis After Primary Anterior Cruciate Ligament Reconstruction: A Cohort Study of 41,976 Patients

BACKGROUND

The reported incidence of posttraumatic knee osteoarthritis (PTOA) after primary anterior cruciate ligament reconstruction (ACLR) varies considerably. Further, there are gaps in identifying which patients are at risk for PTOA after ACLR and whether there are modifiable factors.

PURPOSE

To (1) determine the incidence of PTOA in a primary ACLR cohort and (2) identify patient and perioperative factors associated with the development of PTOA after primary ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data from the Kaiser Permanente ACLR Registry were used to conduct a cohort study. Patients who had undergone primary ACLR without a previous diagnosis of osteoarthritis were identified (2009-2020). The crude incidence of PTOA was calculated using the Aalen-Johansen estimator with a multistate model. The association of patient and operative factors with the development of PTOA after primary ACLR was modeled as a time to event using multistate Cox proportional hazards regression. Models stratified by age (<22 and ≥22 years) were also conducted because of the effect modification of age.

RESULTS

The study sample included 41,976 cases of primary ACLR. The incidence of PTOA was 1.7%, 5.1%, and 13.6% at 2, 5, and 10 year follow-ups, respectively. Risk factors for PTOA that were consistently identified in the overall cohort and age-stratified groups included a body mass index ≥30 versus <30 and an allograft or quadriceps tendon autograft versus a hamstring tendon autograft. Patients presenting with knee pain after ACLR were further identified when considering postoperative factors. Other risk factors for PTOA in the overall cohort included age ≥22 versus <22 years, bone-patellar tendon-bone autograft versus hamstring tendon autograft, hypertension, cartilage injury, meniscal injury, revision after primary ACLR with concomitant meniscal/cartilage surgery, multiligament injury, other activity at the time of injury compared with sport, and tibial tunnel drilling technique rather than the anteromedial portal.

CONCLUSION

Knee pain after ACLR may be an early sign of PTOA. Surgeons should consider the adverse associations of a higher body mass index and an allograft or quadriceps tendon autograft with the development of PTOA, as these were factors identified with a higher risk, regardless of a patient's age at the time of primary ACLR.

Osteoarthritis in the UK Armed Forces: a review of its impact, treatment and future research

Within the UK Armed Forces, musculoskeletal injuries account for over half of all medical downgrades and discharges. Data from other Armed Forces show that osteoarthritis (OA), more common in military personnel, is likely to contribute to this, both in its primary form and following injury (post-traumatic OA, PTOA), which typically presents in the third or fourth decade. OA is not a progressive 'wear and tear' disease, as previously thought, but a heterogenous condition with multiple aetiologies and modulators, including joint damage, abnormal morphology, altered biomechanics, genetics, low-grade inflammation and dysregulated metabolism. Currently, clinical diagnosis, based on symptomatic or radiological criteria, is followed by supportive measures, including education, exercise, analgesia, potentially surgical intervention, with a particular focus on exercise rehabilitation within the UK military. Developments in OA have led to a new paradigm of organ failure, with an emphasis on early diagnosis and risk stratification, prevention strategies (primary, secondary and tertiary) and improved aetiological classification using genotypes and phenotypes to guide management, with the introduction of biological markers (biomarkers) potentially having a role in all these areas. In the UK Armed Forces, there are multiple research studies focused on OA risk factors, epidemiology, biomarkers and effectiveness of different interventions. This review aims to highlight OA, especially PTOA, as an important diagnosis to consider in serving personnel, outline current and future management options, and detail current research trends within the Defence Medical Services.

Concurrent Joint Contact in Anterior Cruciate Ligament Injury induces cartilage micro-injury and subchondral bone sclerosis, resulting in knee osteoarthritis

Objective

Anterior Cruciate Ligament (ACL) injury initiates post-traumatic osteoarthritis (PTOA) via two distinct processes: initial direct contact injury of the cartilage surface during ACL injury, and secondary joint instability due to the ACL deficiency. Using the well-established Compression-induced ACL rupture method (ACL-R) and a novel Non-Compression ACL-R model, we aimed to reveal the individual effects of cartilage compression and joint instability on PTOA progression after ACL injury in mice.

Design

Twelve-week-old C57BL/6J male were randomly divided to three experimental groups: Compression ACL-R, Non-Compression ACL-R, and Intact. Following ACL injury, we performed joint laxity testing and microscopic analysis of the articular cartilage surface at 0 days, in vivo optical imaging of matrix-metalloproteinase (MMP) activity at 3 and 7 days, and histological and microCT analysis at 0, 7, 14, and 28 days.

Results

The Compression ACL-R group exhibited a significant increase of cartilage roughness immediately after injury compared with the Non-Compression group. At 7 days, the Compression group exhibited increased MMP-induced fluorescence intensity and MMP-13 positive cell ratio of chondrocytes. Moreover, histological cartilage degeneration was observable in the Compression group at the same time point. Sclerosis of tibial subchondral bone in the Compression group was more significantly developed than in the Non-Compression group at 28 days.

Conclusions

Both Compression and Non-Compression ACL injury initiated PTOA progression due to joint instability. However, joint contact during ACL rupture also caused initial micro-damage on the cartilage surface and initiated early MMP activity, which could accelerate PTOA progression compared to ACL injury without concurrent joint contact.

Adiposity and cartilage lesions following ACL reconstruction

OBJECTIVE

To determine if global, central, or peripheral adiposity is associated with prevalent and worsening cartilage lesions following anterior cruciate ligament reconstruction (ACLR).

METHODS

In 107 individuals one-year post-ACLR, adiposity was assessed globally (body mass index), centrally (waist circumference), and peripherally (knee subcutaneous adipose tissue thickness) from magnetic resonance imaging (MRI). Tibiofemoral and patellofemoral cartilage lesions were assessed from knee MRIs at 1- and 5-years post-ACLR. Poisson regression evaluated the relation of adiposity with prevalent and worsening tibiofemoral and patellofemoral cartilage lesions adjusting for age, sex, and activity level.

RESULTS

The prevalence ratios of adiposity with tibiofemoral (presence in 49%) and patellofemoral (44%) cartilage lesions ranged from 0.99 to 1.03. Adiposity was more strongly associated with longitudinal changes in tibiofemoral (worsening in 21%) and patellofemoral (44%) cartilage lesions. One-unit increase in global (kg/m2), central (cm), and peripheral (mm) adiposity was associated with a higher risk of worsening tibiofemoral cartilage lesions by 17% (risk ratios [95% confidence interval (CI)]: 1.17 [1.09 to 1.23]), 5% (1.05 [1.02 to 1.08]), and 9% (1.09 [1.03 to 1.16]), and patellofemoral cartilage lesions by 5% (1.05 [1.00 to 1.12]), 2% (1.02 [1.00 to 1.04]) and 2% (1.02 [1.00 to 1.04]), respectively.

CONCLUSION

Greater adiposity was a risk factor for worsening cartilage lesions up to 5 years post-ACLR. Clinical interventions aimed at mitigating excess adiposity may be beneficial in preventive approaches for early post-traumatic osteoarthritis.

Mechanical loading and orthobiologic therapies in the treatment of post-traumatic osteoarthritis (PTOA): a comprehensive review

The importance of mechanical loading and its relationship to orthobiologic therapies in the treatment of post-traumatic osteoarthritis (PTOA) is beginning to receive attention. This review explores the current efficacy of orthobiologic interventions, notably platelet-rich plasma (PRP), bone marrow aspirate (BMA), and mesenchymal stem/stromal cells (MSCs), in combating PTOA drawing from a comprehensive review of both preclinical animal models and human clinical studies. This review suggests why mechanical joint loading, such as running, might improve outcomes in PTOA management in conjunction with orthiobiologic administration. Accumulating evidence underscores the influence of mechanical loading on chondrocyte behavior and its pivotal role in PTOA pathogenesis. Dynamic loading has been identified as a key factor for optimal articular cartilage (AC) health and function, offering the potential to slow down or even reverse PTOA progression. We hypothesize that integrating the activation of mechanotransduction pathways with orthobiologic treatment strategies may hold a key to mitigating or even preventing PTOA development. Specific loading patterns incorporating exercise and physical activity for optimal joint health remain to be defined, particularly in the clinical setting following joint trauma.

Meniscal Repair With Iliotibial Band Grafting and Collagen Membrane Wrapping Augmentation

This work contains a description of the modified Henning operation. This technique can be proven especially useful in difficult cases of damaged meniscus (complex injuries). It consists of three stages: stable suturing of the meniscus, placement of the graft from the iliotibial band on the meniscus, and covering the graft with a collagen membrane. Stitching the meniscus provides initial stabilization, the graft from the iliotibial band provides scaffolding for the reconstructed tissue, and the collagen membrane provides biological stimulation for healing.

Toward designing human intervention studies to prevent osteoarthritis after knee injury: A report from an interdisciplinary OARSI 2023 workshop

Objective

The global impact of osteoarthritis is growing. Currently no disease modifying osteoarthritis drugs/therapies exist, increasing the need for preventative strategies. Knee injuries have a high prevalence, distinct onset, and strong independent association with post-traumatic osteoarthritis (PTOA). Numerous groups are embarking upon research that will culminate in clinical trials to assess the effect of interventions to prevent knee PTOA despite challenges and lack of consensus about trial design in this population. Our objectives were to improve awareness of knee PTOA prevention trial design and discuss state-of-the art methods to address the unique opportunities and challenges of these studies.

Design

An international interdisciplinary group developed a workshop, hosted at the 2023 Osteoarthritis Research Society International Congress. Here we summarize the workshop content and outputs, with the goal of moving the field of PTOA prevention trial design forward.

Results

Workshop highlights included discussions about target population (considering risk, homogeneity, and possibility of modifying osteoarthritis outcome); target treatment (considering delivery, timing, feasibility and effectiveness); comparators (usual care, placebo), and primary symptomatic outcomes considering surrogates and the importance of knee function and symptoms other than pain to this population.

Conclusions

Opportunities to test multimodal PTOA prevention interventions across preclinical models and clinical trials exist. As improving symptomatic outcomes aligns with patient and regulator priorities, co-primary symptomatic (single or aggregate/multidimensional outcome considering function and symptoms beyond pain) and structural/physiological outcomes may be appropriate for these trials. To ensure PTOA prevention trials are relevant and acceptable to all stakeholders, future research should address critical knowledge gaps and challenges.

Chondrocyte-Targeted Delivery System of Sortase A-Engineered Extracellular Vesicles Silencing MMP13 for Osteoarthritis Therapy

Targeted drug delivery and the reduction of off-target effects are crucial for the promising clinical application of nucleic acid drugs. To address this challenge, a new approach for treating osteoarthritis (OA) that accurately delivers antisense oligonucleotides (ASO) targeting matrix metalloproteinase-13 (ASO-MMP13) to chondrocytes, is developed. Small extracellular vesicles (exos) are ligated with chondrocyte affinity peptide (CAP) using Sortase A and subsequently incubated with cholesterol-modified ASO-MMP13 to construct a chondrocyte-targeted drug delivery exo (CAP-exoASO). Compared with exos without CAP (ExoASO), CAP-exoASOs attenuate IL-1β-induced chondrocyte damage and prolong the retention time of ASO-MMP13 in the joint without distribution in major organs following intra-articular injection. Notably, CAP-exoASOs decrease MMP13 expression (P < 0.001) and upregulate COL2A1 expression (P = 0.006), resulting in reorganization of the cartilage matrix and alleviation of progression in the OA model. Furthermore, the Osteoarthritis Research Society International (OARSI) score of articular cartilage tissues treated with CAP-exoASO is comparable with that of healthy rats (P = 0.148). A mechanistic study demonstrates that CAP-exoASO may reduce inflammation by suppressing the IL-17 and TNF signaling pathways. Based on the targeted delivery effect, CAP-exoASOs successfully accomplish cartilage repair and have considerable potential for development as a promising therapeutic modality for satisfactory OA therapy.

Functional meniscus reconstruction with biological and biomechanical heterogeneities through topological self-induction of stem cells

Meniscus injury is one of the most common sports injuries within the knee joint, which is also a crucial pathogenic factor for osteoarthritis (OA). The current meniscus substitution products are far from able to restore meniscal biofunctions due to the inability to reconstruct the gradient heterogeneity of natural meniscus from biological and biomechanical perspectives. Here, inspired by the topology self-induced effect and native meniscus microstructure, we present an innovative tissue-engineered meniscus (TEM) with a unique gradient-sized diamond-pored microstructure (GSDP-TEM) through dual-stage temperature control 3D-printing system based on the mechanical/biocompatibility compatible high Mw poly(ε-caprolactone) (PCL). Biologically, the unique gradient microtopology allows the seeded mesenchymal stem cells with spatially heterogeneous differentiation, triggering gradient transition of the extracellular matrix (ECM) from the inside out. Biomechanically, GSDP-TEM presents excellent circumferential tensile modulus and load transmission ability similar to the natural meniscus. After implantation in rabbit knee, GSDP-TEM induces the regeneration of biomimetic heterogeneous neomeniscus and efficiently alleviates joint degeneration. This study provides an innovative strategy for functional meniscus reconstruction. Topological self-induced cell differentiation and biomechanical property also provides a simple and effective solution for other complex heterogeneous structure reconstructions in the human body and possesses high clinical translational potential.

No effect of dislocation status at arrival in emergency department on outcome of knee joint dislocations

PURPOSE

Knee dislocation is a rare but severe injury of the lower extremities. The aim of this study was to report on the epidemiology, diagnostics and treatment of such injuries and to identify negative predictors of clinical outcomes.

METHODS

This retrospective analysis included all knee dislocations treated at a Level I Trauma Centre in Germany between 2009 and 2021. Medical records were categorised, collected and analysed in a standardised manner. A follow-up visit 1 year after the injury focused on limitations in knee mobility.

RESULTS

A total of 120 knee dislocations were included in the study. 29.3% of patients presented to the emergency department with a dislocated joint, and 17.5% (n = 21) had a neurovascular lesion. At follow-up 12 months after the injury, 65.8% of the patients reported limitations in the range of motion, and 11.7% (n = 14) reported severe limitations in daily activities. Site infections due to surgery occurred in 3.3% of patients. Increased body weight (r = 0.294; p < 0.001 and r = 0.259; p = 0.004), an increased body mass index above 25 kg/m2 (body mass index, r = 0.296; p < 0.001 and r = 0.264; p = 0.004) and deficits in peripheral perfusion as well as sensory and motor function (r = 0.231; p = 0.040 and r = -0.192; p = 0.036) were found to be negative predictive factors for clinical outcome. For posttraumatic neurovascular injury, lack of peripheral perfusion, insufficient sensory and motor function (r = -0.683; p < 0.0001), as well as a higher Schenck grade (r = 0.320; p = 0.037), were identified as independent risk factors. The status of dislocation at the site of the accident and on arrival at the emergency department had no impact on the outcome or neurovascular injury.

CONCLUSION

Knee dislocation is a rare injury with a high rate of severe complications such as neurovascular lesions. In particular, the initial status of neurovascular structures and injury classification showed a relevant negative correlation with the posttraumatic status of nerves and vessels. In particular, patients with these characteristics need close monitoring to prevent negative long-term consequences.

LEVEL OF EVIDENCE

Level III.

Identification of eight genes associated with recurrent patellar dislocation

The inheritance of recurrent patellar dislocation (RPD) is known, but the susceptible gene remains unidentified. Here, we performed the first whole exome sequencing (WES) cohort study to identify the susceptible genes. The results showed eight genes were associated with this disease. Notably, the carboxypeptidase D (CPD) gene showed the highest relevance based on its gene function and tissue expression. Single-cell sequencing results indicate that the CPD gene is involved in the pathophysiological process of RPD through granulocytes. Implicated pathways include nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and Wnt/β-catenin signaling, potentially influencing CPD's role in RPD pathogenesis. This study identified the susceptible gene and investigates the potential pathogenesis of RPD, which provided a new prospect for the understanding of RPD. Besides, it would offer the theoretical basis for disease prevention and genetic counseling.

Editorial Commentary: Meniscal Allograft Transplantation Results in Both Pain Relief and Chondroprotection

Meniscal allograft transplantation (MAT) effectively alleviates symptoms of the meniscus deficiency. Thus, MAT is a widely accepted and recommended treatment for individuals with unicompartmental pain due to meniscus deficiency. Long-term follow-up studies have indicated that MAT yields favorable clinical outcomes, demonstrating high survivorship and low rates of serious complications. In addition, the ability of MAT to function akin to the native meniscus and shield the knee cartilage from osteoarthritis has been a subject of ongoing investigation, and recent direct magnetic resonance imaging evidence shows long-term chondroprotection following MAT. Cartilage lesions worsen during the meniscus deficiency period. Consequently, delaying MAT until patients become more symptomatic may lead to poor outcomes and low graft survivorship due to concomitant cartilage lesions. These findings prompt a reevaluation of the purpose and timing of MAT decisions for meniscectomy patients, suggesting a more proactive approach to recommending MAT, particularly for patients at high risk of postmeniscectomy syndrome and osteoarthritis progression.

Prognostic model to predict the incidence of radiographic knee osteoarthritis

OBJECTIVE

Early diagnosis of knee osteoarthritis (KOA) in asymptomatic stages is essential for the timely management of patients using preventative strategies. We develop and validate a prognostic model useful for predicting the incidence of radiographic KOA (rKOA) in non-radiographic osteoarthritic subjects and stratify individuals at high risk of developing the disease.

METHODS

Subjects without radiographic signs of KOA according to the Kellgren and Lawrence (KL) classification scale (KL=0 in both knees) were enrolled in the OA initiative (OAI) cohort and the Prospective Cohort of A Coruña (PROCOAC). Prognostic models were developed to predict rKOA incidence during a 96-month follow-up period among OAI participants based on clinical variables and serum levels of the candidate protein biomarkers APOA1, APOA4, ZA2G and A2AP. The predictive capability of the biomarkers was assessed based on area under the curve (AUC), and internal validation was performed to correct for overfitting. A nomogram was plotted based on the regression parameters. Model performance was externally validated in the PROCOAC.

RESULTS

282 participants from the OAI were included in the development dataset. The model built with demographic, anthropometric and clinical data (age, sex, body mass index and WOMAC pain score) showed an AUC=0.702 for predicting rKOA incidence during the follow-up. The inclusion of ZA2G, A2AP and APOA1 data significantly improved the model's sensitivity and predictive performance (AUC=0.831). The simplest model, including only clinical covariates and ZA2G and A2AP serum levels, achieved an AUC=0.826. Both models were internally cross-validated. Predictive performance was externally validated in an independent dataset of 100 individuals from the PROCOAC (AUC=0.713).

CONCLUSION

A novel prognostic model based on common clinical variables and protein biomarkers was developed and externally validated to predict rKOA incidence over a 96-month period in individuals without any radiographic signs of disease. The resulting nomogram is a useful tool for stratifying high-risk populations and could potentially lead to personalised medicine strategies for treating OA.